# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========

from mirage.accessor.langfuse import LangfuseAccessor
from mirage.cache.index import NULL_INDEX, IndexCacheStore
from mirage.core.langfuse._client import (fetch_dataset_items,
                                          fetch_dataset_runs, fetch_or_enoent,
                                          fetch_prompt, fetch_trace)
from mirage.core.langfuse.render import json_bytes, jsonl_bytes
from mirage.types import PathSpec
from mirage.utils.errors import enoent
from mirage.utils.key_prefix import mount_prefix_of


async def read(
    accessor: LangfuseAccessor,
    path: PathSpec,
    index: IndexCacheStore = NULL_INDEX,
) -> bytes:
    """Read a file as bytes.

    Args:
        accessor (LangfuseAccessor): langfuse accessor.
        path (str): resource-relative path.
        index (IndexCacheStore): index cache.
        prefix (str): mount prefix for virtual index keys.
    """
    virtual = path.virtual
    mount_prefix_of(path.virtual, path.resource_path)
    key = path.resource_path

    if any(p.startswith(".") for p in key.split("/")):
        raise enoent(virtual)

    parts = key.split("/")

    if parts[0] == "traces" and len(parts) == 2 and parts[1].endswith(".json"):
        trace_id = parts[1].removesuffix(".json")
        data = await fetch_or_enoent(fetch_trace(accessor.api, trace_id),
                                     virtual)
        return json_bytes(data)

    if (parts[0] == "sessions" and len(parts) == 3
            and parts[2].endswith(".json")):
        trace_id = parts[2].removesuffix(".json")
        data = await fetch_or_enoent(fetch_trace(accessor.api, trace_id),
                                     virtual)
        return json_bytes(data)

    if (parts[0] == "prompts" and len(parts) == 3
            and parts[2].endswith(".json")):
        prompt_name = parts[1]
        version = int(parts[2].removesuffix(".json"))
        data = await fetch_or_enoent(
            fetch_prompt(accessor.api, prompt_name, version), virtual)
        return json_bytes(data)

    if (parts[0] == "datasets" and len(parts) == 3
            and parts[2] == "items.jsonl"):
        dataset_name = parts[1]
        items = await fetch_or_enoent(
            fetch_dataset_items(accessor.api, dataset_name), virtual)
        return jsonl_bytes(items)

    if (parts[0] == "datasets" and len(parts) == 4 and parts[2] == "runs"
            and parts[3].endswith(".jsonl")):
        dataset_name = parts[1]
        run_name = parts[3].removesuffix(".jsonl")
        runs = await fetch_or_enoent(
            fetch_dataset_runs(accessor.api, dataset_name), virtual)
        matched = [r for r in runs if r.get("name") == run_name]
        if not matched:
            raise enoent(virtual)
        # A .jsonl path must render as line-delimited JSON, not an indented
        # document: readers that split on newlines (jq) otherwise choke on the
        # first bare brace.
        return jsonl_bytes(matched[:1])

    raise enoent(virtual)
