// ========= 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. =========

import {
  IOResult,
  ResourceName,
  command,
  gunzip,
  materialize,
  readStdinAsync,
  specOf,
  type ByteSource,
  type CommandFnResult,
  type CommandOpts,
  type PathSpec,
} from '@struktoai/mirage-core'
import { stream as diskStream } from '../../../core/disk/stream.ts'
import type { DiskAccessor } from '../../../accessor/disk.ts'

const ENC = new TextEncoder()

async function zcatCommand(
  accessor: DiskAccessor,
  paths: PathSpec[],
  texts: string[],
  opts: CommandOpts,
): Promise<CommandFnResult> {
  let raw: Uint8Array
  if (paths.length > 0 && paths[0] !== undefined) {
    raw = await materialize(diskStream(accessor, paths[0]))
  } else {
    const stdinBytes = await readStdinAsync(opts.stdin)
    if (stdinBytes === null) {
      return [null, new IOResult({ exitCode: 1, stderr: ENC.encode('zcat: missing input\n') })]
    }
    raw = stdinBytes
  }
  const out = await gunzip(raw)
  const result: ByteSource = out
  return [result, new IOResult()]
}

export const DISK_ZCAT = command({
  name: 'zcat',
  resource: ResourceName.DISK,
  spec: specOf('zcat'),
  fn: zcatCommand,
})
