// ========= 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,
  featherCat,
  command,
  materialize,
  specOf,
  type ByteSource,
  type CommandFnResult,
  type CommandOpts,
  type PathSpec,
} from '../../../../index.ts'
import { stream as s3Stream } from '../../../../core/s3/stream.ts'
import type { S3Accessor } from '../../../../accessor/s3.ts'

const ENC = new TextEncoder()

async function catFeatherCommand(
  accessor: S3Accessor,
  paths: PathSpec[],
  _texts: string[],
  _opts: CommandOpts,
): Promise<CommandFnResult> {
  if (paths.length === 0) {
    return [null, new IOResult({ exitCode: 1, stderr: ENC.encode('cat: missing operand\n') })]
  }
  const first = paths[0]
  if (first === undefined) return [null, new IOResult()]
  try {
    const raw = await materialize(s3Stream(accessor, first))
    const result = featherCat(raw)
    const out: ByteSource = result
    return [
      out,
      new IOResult({
        reads: { [first.stripPrefix]: raw },
        cache: [first.stripPrefix],
      }),
    ]
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err)
    return [
      null,
      new IOResult({
        exitCode: 1,
        stderr: ENC.encode(`cat: ${first.original}: failed to read as feather: ${msg}\n`),
      }),
    ]
  }
}

export const S3_CAT_FEATHER = command({
  name: 'cat',
  resource: ResourceName.S3,
  spec: specOf('cat'),
  filetype: '.feather',
  fn: catFeatherCommand,
})
