package github

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	ghErrors "github.com/github/github-mcp-server/pkg/errors"
	"github.com/github/github-mcp-server/pkg/inventory"
	"github.com/github/github-mcp-server/pkg/sanitize"
	"github.com/github/github-mcp-server/pkg/scopes"
	"github.com/github/github-mcp-server/pkg/translations"
	"github.com/github/github-mcp-server/pkg/utils"
	"github.com/google/go-github/v82/github"
	"github.com/google/jsonschema-go/jsonschema"
	"github.com/modelcontextprotocol/go-sdk/mcp"
	"github.com/shurcooL/githubv4"
)

// CloseIssueInput represents the input for closing an issue via the GraphQL API.
// Used to extend the functionality of the githubv4 library to support closing issues as duplicates.
type CloseIssueInput struct {
	IssueID          githubv4.ID             `json:"issueId"`
	ClientMutationID *githubv4.String        `json:"clientMutationId,omitempty"`
	StateReason      *IssueClosedStateReason `json:"stateReason,omitempty"`
	DuplicateIssueID *githubv4.ID            `json:"duplicateIssueId,omitempty"`
}

// IssueClosedStateReason represents the reason an issue was closed.
// Used to extend the functionality of the githubv4 library to support closing issues as duplicates.
type IssueClosedStateReason string

const (
	IssueClosedStateReasonCompleted  IssueClosedStateReason = "COMPLETED"
	IssueClosedStateReasonDuplicate  IssueClosedStateReason = "DUPLICATE"
	IssueClosedStateReasonNotPlanned IssueClosedStateReason = "NOT_PLANNED"
)

// fetchIssueIDs retrieves issue IDs via the GraphQL API.
// When duplicateOf is 0, it fetches only the main issue ID.
// When duplicateOf is non-zero, it fetches both the main issue and duplicate issue IDs in a single query.
func fetchIssueIDs(ctx context.Context, gqlClient *githubv4.Client, owner, repo string, issueNumber int, duplicateOf int) (githubv4.ID, githubv4.ID, error) {
	// Build query variables common to both cases
	vars := map[string]any{
		"owner":       githubv4.String(owner),
		"repo":        githubv4.String(repo),
		"issueNumber": githubv4.Int(issueNumber), // #nosec G115 - issue numbers are always small positive integers
	}

	if duplicateOf == 0 {
		// Only fetch the main issue ID
		var query struct {
			Repository struct {
				Issue struct {
					ID githubv4.ID
				} `graphql:"issue(number: $issueNumber)"`
			} `graphql:"repository(owner: $owner, name: $repo)"`
		}

		if err := gqlClient.Query(ctx, &query, vars); err != nil {
			return "", "", fmt.Errorf("failed to get issue ID")
		}

		return query.Repository.Issue.ID, "", nil
	}

	// Fetch both issue IDs in a single query
	var query struct {
		Repository struct {
			Issue struct {
				ID githubv4.ID
			} `graphql:"issue(number: $issueNumber)"`
			DuplicateIssue struct {
				ID githubv4.ID
			} `graphql:"duplicateIssue: issue(number: $duplicateOf)"`
		} `graphql:"repository(owner: $owner, name: $repo)"`
	}

	// Add duplicate issue number to variables
	vars["duplicateOf"] = githubv4.Int(duplicateOf) // #nosec G115 - issue numbers are always small positive integers

	if err := gqlClient.Query(ctx, &query, vars); err != nil {
		return "", "", fmt.Errorf("failed to get issue ID")
	}

	return query.Repository.Issue.ID, query.Repository.DuplicateIssue.ID, nil
}

// getCloseStateReason converts a string state reason to the appropriate enum value
func getCloseStateReason(stateReason string) IssueClosedStateReason {
	switch stateReason {
	case "not_planned":
		return IssueClosedStateReasonNotPlanned
	case "duplicate":
		return IssueClosedStateReasonDuplicate
	default: // Default to "completed" for empty or "completed" values
		return IssueClosedStateReasonCompleted
	}
}

// IssueFragment represents a fragment of an issue node in the GraphQL API.
type IssueFragment struct {
	Number     githubv4.Int
	Title      githubv4.String
	Body       githubv4.String
	State      githubv4.String
	DatabaseID int64

	Author struct {
		Login githubv4.String
	}
	CreatedAt githubv4.DateTime
	UpdatedAt githubv4.DateTime
	Labels    struct {
		Nodes []struct {
			Name        githubv4.String
			ID          githubv4.String
			Description githubv4.String
		}
	} `graphql:"labels(first: 100)"`
	Comments struct {
		TotalCount githubv4.Int
	} `graphql:"comments"`
}

// Common interface for all issue query types
type IssueQueryResult interface {
	GetIssueFragment() IssueQueryFragment
}

type IssueQueryFragment struct {
	Nodes    []IssueFragment `graphql:"nodes"`
	PageInfo struct {
		HasNextPage     githubv4.Boolean
		HasPreviousPage githubv4.Boolean
		StartCursor     githubv4.String
		EndCursor       githubv4.String
	}
	TotalCount int
}

// ListIssuesQuery is the root query structure for fetching issues with optional label filtering.
type ListIssuesQuery struct {
	Repository struct {
		Issues IssueQueryFragment `graphql:"issues(first: $first, after: $after, states: $states, orderBy: {field: $orderBy, direction: $direction})"`
	} `graphql:"repository(owner: $owner, name: $repo)"`
}

// ListIssuesQueryTypeWithLabels is the query structure for fetching issues with optional label filtering.
type ListIssuesQueryTypeWithLabels struct {
	Repository struct {
		Issues IssueQueryFragment `graphql:"issues(first: $first, after: $after, labels: $labels, states: $states, orderBy: {field: $orderBy, direction: $direction})"`
	} `graphql:"repository(owner: $owner, name: $repo)"`
}

// ListIssuesQueryWithSince is the query structure for fetching issues without label filtering but with since filtering.
type ListIssuesQueryWithSince struct {
	Repository struct {
		Issues IssueQueryFragment `graphql:"issues(first: $first, after: $after, states: $states, orderBy: {field: $orderBy, direction: $direction}, filterBy: {since: $since})"`
	} `graphql:"repository(owner: $owner, name: $repo)"`
}

// ListIssuesQueryTypeWithLabelsWithSince is the query structure for fetching issues with both label and since filtering.
type ListIssuesQueryTypeWithLabelsWithSince struct {
	Repository struct {
		Issues IssueQueryFragment `graphql:"issues(first: $first, after: $after, labels: $labels, states: $states, orderBy: {field: $orderBy, direction: $direction}, filterBy: {since: $since})"`
	} `graphql:"repository(owner: $owner, name: $repo)"`
}

// Implement the interface for all query types
func (q *ListIssuesQueryTypeWithLabels) GetIssueFragment() IssueQueryFragment {
	return q.Repository.Issues
}

func (q *ListIssuesQuery) GetIssueFragment() IssueQueryFragment {
	return q.Repository.Issues
}

func (q *ListIssuesQueryWithSince) GetIssueFragment() IssueQueryFragment {
	return q.Repository.Issues
}

func (q *ListIssuesQueryTypeWithLabelsWithSince) GetIssueFragment() IssueQueryFragment {
	return q.Repository.Issues
}

func getIssueQueryType(hasLabels bool, hasSince bool) any {
	switch {
	case hasLabels && hasSince:
		return &ListIssuesQueryTypeWithLabelsWithSince{}
	case hasLabels:
		return &ListIssuesQueryTypeWithLabels{}
	case hasSince:
		return &ListIssuesQueryWithSince{}
	default:
		return &ListIssuesQuery{}
	}
}

func fragmentToIssue(fragment IssueFragment) *github.Issue {
	// Convert GraphQL labels to GitHub API labels format
	var foundLabels []*github.Label
	for _, labelNode := range fragment.Labels.Nodes {
		foundLabels = append(foundLabels, &github.Label{
			Name:        github.Ptr(string(labelNode.Name)),
			NodeID:      github.Ptr(string(labelNode.ID)),
			Description: github.Ptr(string(labelNode.Description)),
		})
	}

	return &github.Issue{
		Number:    github.Ptr(int(fragment.Number)),
		Title:     github.Ptr(sanitize.Sanitize(string(fragment.Title))),
		CreatedAt: &github.Timestamp{Time: fragment.CreatedAt.Time},
		UpdatedAt: &github.Timestamp{Time: fragment.UpdatedAt.Time},
		User: &github.User{
			Login: github.Ptr(string(fragment.Author.Login)),
		},
		State:    github.Ptr(string(fragment.State)),
		ID:       github.Ptr(fragment.DatabaseID),
		Body:     github.Ptr(sanitize.Sanitize(string(fragment.Body))),
		Labels:   foundLabels,
		Comments: github.Ptr(int(fragment.Comments.TotalCount)),
	}
}

// IssueRead creates a tool to get details of a specific issue in a GitHub repository.
func IssueRead(t translations.TranslationHelperFunc) inventory.ServerTool {
	schema := &jsonschema.Schema{
		Type: "object",
		Properties: map[string]*jsonschema.Schema{
			"method": {
				Type: "string",
				Description: `The read operation to perform on a single issue.
Options are:
1. get - Get details of a specific issue.
2. get_comments - Get issue comments.
3. get_sub_issues - Get sub-issues of the issue.
4. get_labels - Get labels assigned to the issue.
`,
				Enum: []any{"get", "get_comments", "get_sub_issues", "get_labels"},
			},
			"owner": {
				Type:        "string",
				Description: "The owner of the repository",
			},
			"repo": {
				Type:        "string",
				Description: "The name of the repository",
			},
			"issue_number": {
				Type:        "number",
				Description: "The number of the issue",
			},
		},
		Required: []string{"method", "owner", "repo", "issue_number"},
	}
	WithPagination(schema)

	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "issue_read",
			Description: t("TOOL_ISSUE_READ_DESCRIPTION", "Get information about a specific issue in a GitHub repository."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_ISSUE_READ_USER_TITLE", "Get issue details"),
				ReadOnlyHint: true,
			},
			InputSchema: schema,
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			method, err := RequiredParam[string](args, "method")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			repo, err := RequiredParam[string](args, "repo")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			issueNumber, err := RequiredInt(args, "issue_number")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			pagination, err := OptionalPaginationParams(args)
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			client, err := deps.GetClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
			}

			gqlClient, err := deps.GetGQLClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub graphql client", err), nil, nil
			}

			switch method {
			case "get":
				result, err := GetIssue(ctx, client, deps, owner, repo, issueNumber)
				return result, nil, err
			case "get_comments":
				result, err := GetIssueComments(ctx, client, deps, owner, repo, issueNumber, pagination)
				return result, nil, err
			case "get_sub_issues":
				result, err := GetSubIssues(ctx, client, deps, owner, repo, issueNumber, pagination)
				return result, nil, err
			case "get_labels":
				result, err := GetIssueLabels(ctx, gqlClient, owner, repo, issueNumber)
				return result, nil, err
			default:
				return utils.NewToolResultError(fmt.Sprintf("unknown method: %s", method)), nil, nil
			}
		})
}

func GetIssue(ctx context.Context, client *github.Client, deps ToolDependencies, owner string, repo string, issueNumber int) (*mcp.CallToolResult, error) {
	cache, err := deps.GetRepoAccessCache(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
	}
	flags := deps.GetFlags(ctx)

	issue, resp, err := client.Issues.Get(ctx, owner, repo, issueNumber)
	if err != nil {
		return nil, fmt.Errorf("failed to get issue: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to get issue", resp, body), nil
	}

	if flags.LockdownMode {
		if cache == nil {
			return nil, fmt.Errorf("lockdown cache is not configured")
		}
		login := issue.GetUser().GetLogin()
		if login != "" {
			isSafeContent, err := cache.IsSafeContent(ctx, login, owner, repo)
			if err != nil {
				return utils.NewToolResultError(fmt.Sprintf("failed to check lockdown mode: %v", err)), nil
			}
			if !isSafeContent {
				return utils.NewToolResultError("access to issue details is restricted by lockdown mode"), nil
			}
		}
	}

	// Sanitize title/body on response
	if issue != nil {
		if issue.Title != nil {
			issue.Title = github.Ptr(sanitize.Sanitize(*issue.Title))
		}
		if issue.Body != nil {
			issue.Body = github.Ptr(sanitize.Sanitize(*issue.Body))
		}
	}

	minimalIssue := convertToMinimalIssue(issue)

	return MarshalledTextResult(minimalIssue), nil
}

func GetIssueComments(ctx context.Context, client *github.Client, deps ToolDependencies, owner string, repo string, issueNumber int, pagination PaginationParams) (*mcp.CallToolResult, error) {
	cache, err := deps.GetRepoAccessCache(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
	}
	flags := deps.GetFlags(ctx)

	opts := &github.IssueListCommentsOptions{
		ListOptions: github.ListOptions{
			Page:    pagination.Page,
			PerPage: pagination.PerPage,
		},
	}

	comments, resp, err := client.Issues.ListComments(ctx, owner, repo, issueNumber, opts)
	if err != nil {
		return nil, fmt.Errorf("failed to get issue comments: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to get issue comments", resp, body), nil
	}
	if flags.LockdownMode {
		if cache == nil {
			return nil, fmt.Errorf("lockdown cache is not configured")
		}
		filteredComments := make([]*github.IssueComment, 0, len(comments))
		for _, comment := range comments {
			user := comment.User
			if user == nil {
				continue
			}
			login := user.GetLogin()
			if login == "" {
				continue
			}
			isSafeContent, err := cache.IsSafeContent(ctx, login, owner, repo)
			if err != nil {
				return utils.NewToolResultError(fmt.Sprintf("failed to check lockdown mode: %v", err)), nil
			}
			if isSafeContent {
				filteredComments = append(filteredComments, comment)
			}
		}
		comments = filteredComments
	}

	minimalComments := make([]MinimalIssueComment, 0, len(comments))
	for _, comment := range comments {
		minimalComments = append(minimalComments, convertToMinimalIssueComment(comment))
	}

	return MarshalledTextResult(minimalComments), nil
}

func GetSubIssues(ctx context.Context, client *github.Client, deps ToolDependencies, owner string, repo string, issueNumber int, pagination PaginationParams) (*mcp.CallToolResult, error) {
	cache, err := deps.GetRepoAccessCache(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
	}
	featureFlags := deps.GetFlags(ctx)

	opts := &github.IssueListOptions{
		ListOptions: github.ListOptions{
			Page:    pagination.Page,
			PerPage: pagination.PerPage,
		},
	}

	subIssues, resp, err := client.SubIssue.ListByIssue(ctx, owner, repo, int64(issueNumber), opts)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to list sub-issues",
			resp,
			err,
		), nil
	}

	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to list sub-issues", resp, body), nil
	}

	if featureFlags.LockdownMode {
		if cache == nil {
			return nil, fmt.Errorf("lockdown cache is not configured")
		}
		filteredSubIssues := make([]*github.SubIssue, 0, len(subIssues))
		for _, subIssue := range subIssues {
			user := subIssue.User
			if user == nil {
				continue
			}
			login := user.GetLogin()
			if login == "" {
				continue
			}
			isSafeContent, err := cache.IsSafeContent(ctx, login, owner, repo)
			if err != nil {
				return utils.NewToolResultError(fmt.Sprintf("failed to check lockdown mode: %v", err)), nil
			}
			if isSafeContent {
				filteredSubIssues = append(filteredSubIssues, subIssue)
			}
		}
		subIssues = filteredSubIssues
	}

	r, err := json.Marshal(subIssues)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(r)), nil
}

func GetIssueLabels(ctx context.Context, client *githubv4.Client, owner string, repo string, issueNumber int) (*mcp.CallToolResult, error) {
	// Get current labels on the issue using GraphQL
	var query struct {
		Repository struct {
			Issue struct {
				Labels struct {
					Nodes []struct {
						ID          githubv4.ID
						Name        githubv4.String
						Color       githubv4.String
						Description githubv4.String
					}
					TotalCount githubv4.Int
				} `graphql:"labels(first: 100)"`
			} `graphql:"issue(number: $issueNumber)"`
		} `graphql:"repository(owner: $owner, name: $repo)"`
	}

	vars := map[string]any{
		"owner":       githubv4.String(owner),
		"repo":        githubv4.String(repo),
		"issueNumber": githubv4.Int(issueNumber), // #nosec G115 - issue numbers are always small positive integers
	}

	if err := client.Query(ctx, &query, vars); err != nil {
		return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "Failed to get issue labels", err), nil
	}

	// Extract label information
	issueLabels := make([]map[string]any, len(query.Repository.Issue.Labels.Nodes))
	for i, label := range query.Repository.Issue.Labels.Nodes {
		issueLabels[i] = map[string]any{
			"id":          fmt.Sprintf("%v", label.ID),
			"name":        string(label.Name),
			"color":       string(label.Color),
			"description": string(label.Description),
		}
	}

	response := map[string]any{
		"labels":     issueLabels,
		"totalCount": int(query.Repository.Issue.Labels.TotalCount),
	}

	out, err := json.Marshal(response)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(out)), nil

}

// ListIssueTypes creates a tool to list defined issue types for an organization. This can be used to understand supported issue type values for creating or updating issues.
func ListIssueTypes(t translations.TranslationHelperFunc) inventory.ServerTool {
	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "list_issue_types",
			Description: t("TOOL_LIST_ISSUE_TYPES_FOR_ORG", "List supported issue types for repository owner (organization)."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_LIST_ISSUE_TYPES_USER_TITLE", "List available issue types"),
				ReadOnlyHint: true,
			},
			InputSchema: &jsonschema.Schema{
				Type: "object",
				Properties: map[string]*jsonschema.Schema{
					"owner": {
						Type:        "string",
						Description: "The organization owner of the repository",
					},
				},
				Required: []string{"owner"},
			},
		},
		[]scopes.Scope{scopes.ReadOrg},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			client, err := deps.GetClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
			}
			issueTypes, resp, err := client.Organizations.ListIssueTypes(ctx, owner)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to list issue types", err), nil, nil
			}
			defer func() { _ = resp.Body.Close() }()

			if resp.StatusCode != http.StatusOK {
				body, err := io.ReadAll(resp.Body)
				if err != nil {
					return utils.NewToolResultErrorFromErr("failed to read response body", err), nil, nil
				}
				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to list issue types", resp, body), nil, nil
			}

			r, err := json.Marshal(issueTypes)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to marshal issue types", err), nil, nil
			}

			return utils.NewToolResultText(string(r)), nil, nil
		})
}

// AddIssueComment creates a tool to add a comment to an issue.
func AddIssueComment(t translations.TranslationHelperFunc) inventory.ServerTool {
	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "add_issue_comment",
			Description: t("TOOL_ADD_ISSUE_COMMENT_DESCRIPTION", "Add a comment to a specific issue in a GitHub repository. Use this tool to add comments to pull requests as well (in this case pass pull request number as issue_number), but only if user is not asking specifically to add review comments."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_ADD_ISSUE_COMMENT_USER_TITLE", "Add comment to issue"),
				ReadOnlyHint: false,
			},
			InputSchema: &jsonschema.Schema{
				Type: "object",
				Properties: map[string]*jsonschema.Schema{
					"owner": {
						Type:        "string",
						Description: "Repository owner",
					},
					"repo": {
						Type:        "string",
						Description: "Repository name",
					},
					"issue_number": {
						Type:        "number",
						Description: "Issue number to comment on",
					},
					"body": {
						Type:        "string",
						Description: "Comment content",
					},
				},
				Required: []string{"owner", "repo", "issue_number", "body"},
			},
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			repo, err := RequiredParam[string](args, "repo")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			issueNumber, err := RequiredInt(args, "issue_number")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			body, err := RequiredParam[string](args, "body")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			comment := &github.IssueComment{
				Body: github.Ptr(body),
			}

			client, err := deps.GetClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
			}
			createdComment, resp, err := client.Issues.CreateComment(ctx, owner, repo, issueNumber, comment)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to create comment", err), nil, nil
			}
			defer func() { _ = resp.Body.Close() }()

			if resp.StatusCode != http.StatusCreated {
				body, err := io.ReadAll(resp.Body)
				if err != nil {
					return utils.NewToolResultErrorFromErr("failed to read response body", err), nil, nil
				}
				return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create comment", resp, body), nil, nil
			}

			minimalResponse := MinimalResponse{
				ID:  fmt.Sprintf("%d", createdComment.GetID()),
				URL: createdComment.GetHTMLURL(),
			}

			r, err := json.Marshal(minimalResponse)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to marshal response", err), nil, nil
			}

			return utils.NewToolResultText(string(r)), nil, nil
		})
}

// SubIssueWrite creates a tool to add a sub-issue to a parent issue.
func SubIssueWrite(t translations.TranslationHelperFunc) inventory.ServerTool {
	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "sub_issue_write",
			Description: t("TOOL_SUB_ISSUE_WRITE_DESCRIPTION", "Add a sub-issue to a parent issue in a GitHub repository."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_SUB_ISSUE_WRITE_USER_TITLE", "Change sub-issue"),
				ReadOnlyHint: false,
			},
			InputSchema: &jsonschema.Schema{
				Type: "object",
				Properties: map[string]*jsonschema.Schema{
					"method": {
						Type: "string",
						Description: `The action to perform on a single sub-issue
Options are:
- 'add' - add a sub-issue to a parent issue in a GitHub repository.
- 'remove' - remove a sub-issue from a parent issue in a GitHub repository.
- 'reprioritize' - change the order of sub-issues within a parent issue in a GitHub repository. Use either 'after_id' or 'before_id' to specify the new position.
				`,
					},
					"owner": {
						Type:        "string",
						Description: "Repository owner",
					},
					"repo": {
						Type:        "string",
						Description: "Repository name",
					},
					"issue_number": {
						Type:        "number",
						Description: "The number of the parent issue",
					},
					"sub_issue_id": {
						Type:        "number",
						Description: "The ID of the sub-issue to add. ID is not the same as issue number",
					},
					"replace_parent": {
						Type:        "boolean",
						Description: "When true, replaces the sub-issue's current parent issue. Use with 'add' method only.",
					},
					"after_id": {
						Type:        "number",
						Description: "The ID of the sub-issue to be prioritized after (either after_id OR before_id should be specified)",
					},
					"before_id": {
						Type:        "number",
						Description: "The ID of the sub-issue to be prioritized before (either after_id OR before_id should be specified)",
					},
				},
				Required: []string{"method", "owner", "repo", "issue_number", "sub_issue_id"},
			},
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			method, err := RequiredParam[string](args, "method")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			repo, err := RequiredParam[string](args, "repo")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			issueNumber, err := RequiredInt(args, "issue_number")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			subIssueID, err := RequiredInt(args, "sub_issue_id")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			replaceParent, err := OptionalParam[bool](args, "replace_parent")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			afterID, err := OptionalIntParam(args, "after_id")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			beforeID, err := OptionalIntParam(args, "before_id")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			client, err := deps.GetClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
			}

			switch strings.ToLower(method) {
			case "add":
				result, err := AddSubIssue(ctx, client, owner, repo, issueNumber, subIssueID, replaceParent)
				return result, nil, err
			case "remove":
				// Call the remove sub-issue function
				result, err := RemoveSubIssue(ctx, client, owner, repo, issueNumber, subIssueID)
				return result, nil, err
			case "reprioritize":
				// Call the reprioritize sub-issue function
				result, err := ReprioritizeSubIssue(ctx, client, owner, repo, issueNumber, subIssueID, afterID, beforeID)
				return result, nil, err
			default:
				return utils.NewToolResultError(fmt.Sprintf("unknown method: %s", method)), nil, nil
			}
		})
}

func AddSubIssue(ctx context.Context, client *github.Client, owner string, repo string, issueNumber int, subIssueID int, replaceParent bool) (*mcp.CallToolResult, error) {
	subIssueRequest := github.SubIssueRequest{
		SubIssueID:    int64(subIssueID),
		ReplaceParent: github.Ptr(replaceParent),
	}

	subIssue, resp, err := client.SubIssue.Add(ctx, owner, repo, int64(issueNumber), subIssueRequest)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to add sub-issue",
			resp,
			err,
		), nil
	}

	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusCreated {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to add sub-issue", resp, body), nil
	}

	r, err := json.Marshal(subIssue)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(r)), nil

}

func RemoveSubIssue(ctx context.Context, client *github.Client, owner string, repo string, issueNumber int, subIssueID int) (*mcp.CallToolResult, error) {
	subIssueRequest := github.SubIssueRequest{
		SubIssueID: int64(subIssueID),
	}

	subIssue, resp, err := client.SubIssue.Remove(ctx, owner, repo, int64(issueNumber), subIssueRequest)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to remove sub-issue",
			resp,
			err,
		), nil
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to remove sub-issue", resp, body), nil
	}

	r, err := json.Marshal(subIssue)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(r)), nil
}

func ReprioritizeSubIssue(ctx context.Context, client *github.Client, owner string, repo string, issueNumber int, subIssueID int, afterID int, beforeID int) (*mcp.CallToolResult, error) {
	// Validate that either after_id or before_id is specified, but not both
	if afterID == 0 && beforeID == 0 {
		return utils.NewToolResultError("either after_id or before_id must be specified"), nil
	}
	if afterID != 0 && beforeID != 0 {
		return utils.NewToolResultError("only one of after_id or before_id should be specified, not both"), nil
	}

	subIssueRequest := github.SubIssueRequest{
		SubIssueID: int64(subIssueID),
	}

	if afterID != 0 {
		afterIDInt64 := int64(afterID)
		subIssueRequest.AfterID = &afterIDInt64
	}
	if beforeID != 0 {
		beforeIDInt64 := int64(beforeID)
		subIssueRequest.BeforeID = &beforeIDInt64
	}

	subIssue, resp, err := client.SubIssue.Reprioritize(ctx, owner, repo, int64(issueNumber), subIssueRequest)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to reprioritize sub-issue",
			resp,
			err,
		), nil
	}

	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to reprioritize sub-issue", resp, body), nil
	}

	r, err := json.Marshal(subIssue)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(r)), nil
}

// SearchIssues creates a tool to search for issues.
func SearchIssues(t translations.TranslationHelperFunc) inventory.ServerTool {
	schema := &jsonschema.Schema{
		Type: "object",
		Properties: map[string]*jsonschema.Schema{
			"query": {
				Type:        "string",
				Description: "Search query using GitHub issues search syntax",
			},
			"owner": {
				Type:        "string",
				Description: "Optional repository owner. If provided with repo, only issues for this repository are listed.",
			},
			"repo": {
				Type:        "string",
				Description: "Optional repository name. If provided with owner, only issues for this repository are listed.",
			},
			"sort": {
				Type:        "string",
				Description: "Sort field by number of matches of categories, defaults to best match",
				Enum: []any{
					"comments",
					"reactions",
					"reactions-+1",
					"reactions--1",
					"reactions-smile",
					"reactions-thinking_face",
					"reactions-heart",
					"reactions-tada",
					"interactions",
					"created",
					"updated",
				},
			},
			"order": {
				Type:        "string",
				Description: "Sort order",
				Enum:        []any{"asc", "desc"},
			},
		},
		Required: []string{"query"},
	}
	WithPagination(schema)

	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "search_issues",
			Description: t("TOOL_SEARCH_ISSUES_DESCRIPTION", "Search for issues in GitHub repositories using issues search syntax already scoped to is:issue"),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_SEARCH_ISSUES_USER_TITLE", "Search issues"),
				ReadOnlyHint: true,
			},
			InputSchema: schema,
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			result, err := searchHandler(ctx, deps.GetClient, args, "issue", "failed to search issues")
			return result, nil, err
		})
}

// IssueWrite creates a tool to create a new or update an existing issue in a GitHub repository.
// IssueWriteUIResourceURI is the URI for the issue_write tool's MCP App UI resource.
const IssueWriteUIResourceURI = "ui://github-mcp-server/issue-write"

func IssueWrite(t translations.TranslationHelperFunc) inventory.ServerTool {
	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "issue_write",
			Description: t("TOOL_ISSUE_WRITE_DESCRIPTION", "Create a new or update an existing issue in a GitHub repository."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_ISSUE_WRITE_USER_TITLE", "Create or update issue."),
				ReadOnlyHint: false,
			},
			Meta: mcp.Meta{
				"ui": map[string]any{
					"resourceUri": IssueWriteUIResourceURI,
					"visibility":  []string{"model", "app"},
				},
			},
			InputSchema: &jsonschema.Schema{
				Type: "object",
				Properties: map[string]*jsonschema.Schema{
					"method": {
						Type: "string",
						Description: `Write operation to perform on a single issue.
Options are:
- 'create' - creates a new issue.
- 'update' - updates an existing issue.
`,
						Enum: []any{"create", "update"},
					},
					"owner": {
						Type:        "string",
						Description: "Repository owner",
					},
					"repo": {
						Type:        "string",
						Description: "Repository name",
					},
					"issue_number": {
						Type:        "number",
						Description: "Issue number to update",
					},
					"title": {
						Type:        "string",
						Description: "Issue title",
					},
					"body": {
						Type:        "string",
						Description: "Issue body content",
					},
					"assignees": {
						Type:        "array",
						Description: "Usernames to assign to this issue",
						Items: &jsonschema.Schema{
							Type: "string",
						},
					},
					"labels": {
						Type:        "array",
						Description: "Labels to apply to this issue",
						Items: &jsonschema.Schema{
							Type: "string",
						},
					},
					"milestone": {
						Type:        "number",
						Description: "Milestone number",
					},
					"type": {
						Type:        "string",
						Description: "Type of this issue. Only use if the repository has issue types configured. Use list_issue_types tool to get valid type values for the organization. If the repository doesn't support issue types, omit this parameter.",
					},
					"state": {
						Type:        "string",
						Description: "New state",
						Enum:        []any{"open", "closed"},
					},
					"state_reason": {
						Type:        "string",
						Description: "Reason for the state change. Ignored unless state is changed.",
						Enum:        []any{"completed", "not_planned", "duplicate"},
					},
					"duplicate_of": {
						Type:        "number",
						Description: "Issue number that this issue is a duplicate of. Only used when state_reason is 'duplicate'.",
					},
				},
				Required: []string{"method", "owner", "repo"},
			},
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, req *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			method, err := RequiredParam[string](args, "method")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			repo, err := RequiredParam[string](args, "repo")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// When insiders mode is enabled and the client supports MCP Apps UI,
			// check if this is a UI form submission. The UI sends _ui_submitted=true
			// to distinguish form submissions from LLM calls.
			uiSubmitted, _ := OptionalParam[bool](args, "_ui_submitted")

			if deps.GetFlags(ctx).InsidersMode && clientSupportsUI(ctx, req) && !uiSubmitted {
				if method == "update" {
					issueNumber, numErr := RequiredInt(args, "issue_number")
					if numErr != nil {
						return utils.NewToolResultError("issue_number is required for update method"), nil, nil
					}
					return utils.NewToolResultText(fmt.Sprintf("Ready to update issue #%d in %s/%s. The user will review and confirm via the interactive form.", issueNumber, owner, repo)), nil, nil
				}
				return utils.NewToolResultText(fmt.Sprintf("Ready to create an issue in %s/%s. The user will review and confirm via the interactive form.", owner, repo)), nil, nil
			}

			title, err := OptionalParam[string](args, "title")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Optional parameters
			body, err := OptionalParam[string](args, "body")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Get assignees
			assignees, err := OptionalStringArrayParam(args, "assignees")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Get labels
			labels, err := OptionalStringArrayParam(args, "labels")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Get optional milestone
			milestone, err := OptionalIntParam(args, "milestone")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			var milestoneNum int
			if milestone != 0 {
				milestoneNum = milestone
			}

			// Get optional type
			issueType, err := OptionalParam[string](args, "type")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Handle state, state_reason and duplicateOf parameters
			state, err := OptionalParam[string](args, "state")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			stateReason, err := OptionalParam[string](args, "state_reason")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			duplicateOf, err := OptionalIntParam(args, "duplicate_of")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			if duplicateOf != 0 && stateReason != "duplicate" {
				return utils.NewToolResultError("duplicate_of can only be used when state_reason is 'duplicate'"), nil, nil
			}

			client, err := deps.GetClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GitHub client", err), nil, nil
			}

			gqlClient, err := deps.GetGQLClient(ctx)
			if err != nil {
				return utils.NewToolResultErrorFromErr("failed to get GraphQL client", err), nil, nil
			}

			switch method {
			case "create":
				result, err := CreateIssue(ctx, client, owner, repo, title, body, assignees, labels, milestoneNum, issueType)
				return result, nil, err
			case "update":
				issueNumber, err := RequiredInt(args, "issue_number")
				if err != nil {
					return utils.NewToolResultError(err.Error()), nil, nil
				}
				result, err := UpdateIssue(ctx, client, gqlClient, owner, repo, issueNumber, title, body, assignees, labels, milestoneNum, issueType, state, stateReason, duplicateOf)
				return result, nil, err
			default:
				return utils.NewToolResultError("invalid method, must be either 'create' or 'update'"), nil, nil
			}
		})
}

func CreateIssue(ctx context.Context, client *github.Client, owner string, repo string, title string, body string, assignees []string, labels []string, milestoneNum int, issueType string) (*mcp.CallToolResult, error) {
	if title == "" {
		return utils.NewToolResultError("missing required parameter: title"), nil
	}

	// Create the issue request
	issueRequest := &github.IssueRequest{
		Title:     github.Ptr(title),
		Body:      github.Ptr(body),
		Assignees: &assignees,
		Labels:    &labels,
	}

	if milestoneNum != 0 {
		issueRequest.Milestone = &milestoneNum
	}

	if issueType != "" {
		issueRequest.Type = github.Ptr(issueType)
	}

	issue, resp, err := client.Issues.Create(ctx, owner, repo, issueRequest)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to create issue",
			resp,
			err,
		), nil
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusCreated {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return utils.NewToolResultErrorFromErr("failed to read response body", err), nil
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to create issue", resp, body), nil
	}

	// Return minimal response with just essential information
	minimalResponse := MinimalResponse{
		ID:  fmt.Sprintf("%d", issue.GetID()),
		URL: issue.GetHTMLURL(),
	}

	r, err := json.Marshal(minimalResponse)
	if err != nil {
		return utils.NewToolResultErrorFromErr("failed to marshal response", err), nil
	}

	return utils.NewToolResultText(string(r)), nil
}

func UpdateIssue(ctx context.Context, client *github.Client, gqlClient *githubv4.Client, owner string, repo string, issueNumber int, title string, body string, assignees []string, labels []string, milestoneNum int, issueType string, state string, stateReason string, duplicateOf int) (*mcp.CallToolResult, error) {
	// Create the issue request with only provided fields
	issueRequest := &github.IssueRequest{}

	// Set optional parameters if provided
	if title != "" {
		issueRequest.Title = github.Ptr(title)
	}

	if body != "" {
		issueRequest.Body = github.Ptr(body)
	}

	if len(labels) > 0 {
		issueRequest.Labels = &labels
	}

	if len(assignees) > 0 {
		issueRequest.Assignees = &assignees
	}

	if milestoneNum != 0 {
		issueRequest.Milestone = &milestoneNum
	}

	if issueType != "" {
		issueRequest.Type = github.Ptr(issueType)
	}

	updatedIssue, resp, err := client.Issues.Edit(ctx, owner, repo, issueNumber, issueRequest)
	if err != nil {
		return ghErrors.NewGitHubAPIErrorResponse(ctx,
			"failed to update issue",
			resp,
			err,
		), nil
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read response body: %w", err)
		}
		return ghErrors.NewGitHubAPIStatusErrorResponse(ctx, "failed to update issue", resp, body), nil
	}

	// Use GraphQL API for state updates
	if state != "" {
		// Mandate specifying duplicateOf when trying to close as duplicate
		if state == "closed" && stateReason == "duplicate" && duplicateOf == 0 {
			return utils.NewToolResultError("duplicate_of must be provided when state_reason is 'duplicate'"), nil
		}

		// Get target issue ID (and duplicate issue ID if needed)
		issueID, duplicateIssueID, err := fetchIssueIDs(ctx, gqlClient, owner, repo, issueNumber, duplicateOf)
		if err != nil {
			return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "Failed to find issues", err), nil
		}

		switch state {
		case "open":
			// Use ReopenIssue mutation for opening
			var mutation struct {
				ReopenIssue struct {
					Issue struct {
						ID     githubv4.ID
						Number githubv4.Int
						URL    githubv4.String
						State  githubv4.String
					}
				} `graphql:"reopenIssue(input: $input)"`
			}

			err = gqlClient.Mutate(ctx, &mutation, githubv4.ReopenIssueInput{
				IssueID: issueID,
			}, nil)
			if err != nil {
				return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "Failed to reopen issue", err), nil
			}
		case "closed":
			// Use CloseIssue mutation for closing
			var mutation struct {
				CloseIssue struct {
					Issue struct {
						ID     githubv4.ID
						Number githubv4.Int
						URL    githubv4.String
						State  githubv4.String
					}
				} `graphql:"closeIssue(input: $input)"`
			}

			stateReasonValue := getCloseStateReason(stateReason)
			closeInput := CloseIssueInput{
				IssueID:     issueID,
				StateReason: &stateReasonValue,
			}

			// Set duplicate issue ID if needed
			if stateReason == "duplicate" {
				closeInput.DuplicateIssueID = &duplicateIssueID
			}

			err = gqlClient.Mutate(ctx, &mutation, closeInput, nil)
			if err != nil {
				return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "Failed to close issue", err), nil
			}
		}
	}

	// Return minimal response with just essential information
	minimalResponse := MinimalResponse{
		ID:  fmt.Sprintf("%d", updatedIssue.GetID()),
		URL: updatedIssue.GetHTMLURL(),
	}

	r, err := json.Marshal(minimalResponse)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal response: %w", err)
	}

	return utils.NewToolResultText(string(r)), nil
}

// ListIssues creates a tool to list and filter repository issues
func ListIssues(t translations.TranslationHelperFunc) inventory.ServerTool {
	schema := &jsonschema.Schema{
		Type: "object",
		Properties: map[string]*jsonschema.Schema{
			"owner": {
				Type:        "string",
				Description: "Repository owner",
			},
			"repo": {
				Type:        "string",
				Description: "Repository name",
			},
			"state": {
				Type:        "string",
				Description: "Filter by state, by default both open and closed issues are returned when not provided",
				Enum:        []any{"OPEN", "CLOSED"},
			},
			"labels": {
				Type:        "array",
				Description: "Filter by labels",
				Items: &jsonschema.Schema{
					Type: "string",
				},
			},
			"orderBy": {
				Type:        "string",
				Description: "Order issues by field. If provided, the 'direction' also needs to be provided.",
				Enum:        []any{"CREATED_AT", "UPDATED_AT", "COMMENTS"},
			},
			"direction": {
				Type:        "string",
				Description: "Order direction. If provided, the 'orderBy' also needs to be provided.",
				Enum:        []any{"ASC", "DESC"},
			},
			"since": {
				Type:        "string",
				Description: "Filter by date (ISO 8601 timestamp)",
			},
		},
		Required: []string{"owner", "repo"},
	}
	WithCursorPagination(schema)

	return NewTool(
		ToolsetMetadataIssues,
		mcp.Tool{
			Name:        "list_issues",
			Description: t("TOOL_LIST_ISSUES_DESCRIPTION", "List issues in a GitHub repository. For pagination, use the 'endCursor' from the previous response's 'pageInfo' in the 'after' parameter."),
			Annotations: &mcp.ToolAnnotations{
				Title:        t("TOOL_LIST_ISSUES_USER_TITLE", "List issues"),
				ReadOnlyHint: true,
			},
			InputSchema: schema,
		},
		[]scopes.Scope{scopes.Repo},
		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
			owner, err := RequiredParam[string](args, "owner")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}
			repo, err := RequiredParam[string](args, "repo")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Set optional parameters if provided
			state, err := OptionalParam[string](args, "state")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Normalize and filter by state
			state = strings.ToUpper(state)
			var states []githubv4.IssueState

			switch state {
			case "OPEN", "CLOSED":
				states = []githubv4.IssueState{githubv4.IssueState(state)}
			default:
				states = []githubv4.IssueState{githubv4.IssueStateOpen, githubv4.IssueStateClosed}
			}

			// Get labels
			labels, err := OptionalStringArrayParam(args, "labels")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			orderBy, err := OptionalParam[string](args, "orderBy")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			direction, err := OptionalParam[string](args, "direction")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// Normalize and validate orderBy
			orderBy = strings.ToUpper(orderBy)
			switch orderBy {
			case "CREATED_AT", "UPDATED_AT", "COMMENTS":
				// Valid, keep as is
			default:
				orderBy = "CREATED_AT"
			}

			// Normalize and validate direction
			direction = strings.ToUpper(direction)
			switch direction {
			case "ASC", "DESC":
				// Valid, keep as is
			default:
				direction = "DESC"
			}

			since, err := OptionalParam[string](args, "since")
			if err != nil {
				return utils.NewToolResultError(err.Error()), nil, nil
			}

			// There are two optional parameters: since and labels.
			var sinceTime time.Time
			var hasSince bool
			if since != "" {
				sinceTime, err = parseISOTimestamp(since)
				if err != nil {
					return utils.NewToolResultError(fmt.Sprintf("failed to list issues: %s", err.Error())), nil, nil
				}
				hasSince = true
			}
			hasLabels := len(labels) > 0

			// Get pagination parameters and convert to GraphQL format
			pagination, err := OptionalCursorPaginationParams(args)
			if err != nil {
				return nil, nil, err
			}

			// Check if someone tried to use page-based pagination instead of cursor-based
			if _, pageProvided := args["page"]; pageProvided {
				return utils.NewToolResultError("This tool uses cursor-based pagination. Use the 'after' parameter with the 'endCursor' value from the previous response instead of 'page'."), nil, nil
			}

			// Check if pagination parameters were explicitly provided
			_, perPageProvided := args["perPage"]
			paginationExplicit := perPageProvided

			paginationParams, err := pagination.ToGraphQLParams()
			if err != nil {
				return nil, nil, err
			}

			// Use default of 30 if pagination was not explicitly provided
			if !paginationExplicit {
				defaultFirst := int32(DefaultGraphQLPageSize)
				paginationParams.First = &defaultFirst
			}

			client, err := deps.GetGQLClient(ctx)
			if err != nil {
				return utils.NewToolResultError(fmt.Sprintf("failed to get GitHub GQL client: %v", err)), nil, nil
			}

			vars := map[string]any{
				"owner":     githubv4.String(owner),
				"repo":      githubv4.String(repo),
				"states":    states,
				"orderBy":   githubv4.IssueOrderField(orderBy),
				"direction": githubv4.OrderDirection(direction),
				"first":     githubv4.Int(*paginationParams.First),
			}

			if paginationParams.After != nil {
				vars["after"] = githubv4.String(*paginationParams.After)
			} else {
				// Used within query, therefore must be set to nil and provided as $after
				vars["after"] = (*githubv4.String)(nil)
			}

			// Ensure optional parameters are set
			if hasLabels {
				// Use query with labels filtering - convert string labels to githubv4.String slice
				labelStrings := make([]githubv4.String, len(labels))
				for i, label := range labels {
					labelStrings[i] = githubv4.String(label)
				}
				vars["labels"] = labelStrings
			}

			if hasSince {
				vars["since"] = githubv4.DateTime{Time: sinceTime}
			}

			issueQuery := getIssueQueryType(hasLabels, hasSince)
			if err := client.Query(ctx, issueQuery, vars); err != nil {
				return ghErrors.NewGitHubGraphQLErrorResponse(
					ctx,
					"failed to list issues",
					err,
				), nil, nil
			}

			// Extract and convert all issue nodes using the common interface
			var issues []*github.Issue
			var pageInfo struct {
				HasNextPage     githubv4.Boolean
				HasPreviousPage githubv4.Boolean
				StartCursor     githubv4.String
				EndCursor       githubv4.String
			}
			var totalCount int

			if queryResult, ok := issueQuery.(IssueQueryResult); ok {
				fragment := queryResult.GetIssueFragment()
				for _, issue := range fragment.Nodes {
					issues = append(issues, fragmentToIssue(issue))
				}
				pageInfo = fragment.PageInfo
				totalCount = fragment.TotalCount
			}

			// Create response with issues
			response := map[string]any{
				"issues": issues,
				"pageInfo": map[string]any{
					"hasNextPage":     pageInfo.HasNextPage,
					"hasPreviousPage": pageInfo.HasPreviousPage,
					"startCursor":     string(pageInfo.StartCursor),
					"endCursor":       string(pageInfo.EndCursor),
				},
				"totalCount": totalCount,
			}
			out, err := json.Marshal(response)
			if err != nil {
				return nil, nil, fmt.Errorf("failed to marshal issues: %w", err)
			}
			return utils.NewToolResultText(string(out)), nil, nil
		})
}

// parseISOTimestamp parses an ISO 8601 timestamp string into a time.Time object.
// Returns the parsed time or an error if parsing fails.
// Example formats supported: "2023-01-15T14:30:00Z", "2023-01-15"
func parseISOTimestamp(timestamp string) (time.Time, error) {
	if timestamp == "" {
		return time.Time{}, fmt.Errorf("empty timestamp")
	}

	// Try RFC3339 format (standard ISO 8601 with time)
	t, err := time.Parse(time.RFC3339, timestamp)
	if err == nil {
		return t, nil
	}

	// Try simple date format (YYYY-MM-DD)
	t, err = time.Parse("2006-01-02", timestamp)
	if err == nil {
		return t, nil
	}

	// Return error with supported formats
	return time.Time{}, fmt.Errorf("invalid ISO 8601 timestamp: %s (supported formats: YYYY-MM-DDThh:mm:ssZ or YYYY-MM-DD)", timestamp)
}