#!/usr/bin/env node

import fs from 'node:fs';
import path from 'node:path';
import process from 'node:process';

const ROOT_DIR = path.resolve(import.meta.dirname, '..');
const STATE_DIR = path.join(ROOT_DIR, 'state', 'subagent-delivery-watchdog');

function parseArgs(argv) {
  const args = {
    compact: false,
    input: null,
    help: false,
  };

  for (let i = 0; i < argv.length; i += 1) {
    const token = argv[i];

    if (token === '--compact') {
      args.compact = true;
      continue;
    }

    if (token === '--help' || token === '-h') {
      args.help = true;
      continue;
    }

    if (token === '--input') {
      args.input = argv[i + 1] ?? null;
      i += 1;
      continue;
    }

    if (token.startsWith('--input=')) {
      args.input = token.slice('--input='.length) || null;
      continue;
    }
  }

  return args;
}

function printHelp() {
  const lines = [
    'Usage: node scripts/subagent_delivery_watchdog.mjs [--compact] [--input <path>]',
    '',
    'Minimal CLI skeleton for the subagent delivery watchdog.',
  ];
  process.stdout.write(`${lines.join('\n')}\n`);
}

function tryReadInput(inputPath) {
  if (!inputPath) {
    return {
      path: null,
      exists: false,
      bytes: 0,
      preview: '',
    };
  }

  try {
    const content = fs.readFileSync(inputPath, 'utf8');
    return {
      path: inputPath,
      exists: true,
      bytes: Buffer.byteLength(content, 'utf8'),
      preview: content.slice(0, 200),
      content,
    };
  } catch (error) {
    return {
      path: inputPath,
      exists: false,
      bytes: 0,
      preview: '',
      error: error instanceof Error ? error.message : String(error),
    };
  }
}

function tryParseJson(content) {
  if (typeof content !== 'string' || content.length === 0) {
    return null;
  }

  try {
    return JSON.parse(content);
  } catch {
    return null;
  }
}

function writeDispatchReceiptState(payload) {
  if (!payload || typeof payload !== 'object') {
    return null;
  }

  const { runId, childSessionKey, dispatchAt, expectedBy } = payload;

  if (![runId, childSessionKey, dispatchAt, expectedBy].every((value) => typeof value === 'string' && value.length > 0)) {
    return null;
  }

  fs.mkdirSync(STATE_DIR, { recursive: true });

  const statePath = path.join(STATE_DIR, `${runId}.json`);
  const dispatchRecord = {
    runId,
    childSessionKey,
    dispatchAt,
    expectedBy,
  };

  fs.writeFileSync(statePath, `${JSON.stringify(dispatchRecord, null, 2)}\n`, 'utf8');

  return {
    statePath,
    record: dispatchRecord,
  };
}

function main() {
  const args = parseArgs(process.argv.slice(2));

  if (args.help) {
    printHelp();
    process.exit(0);
  }

  const input = tryReadInput(args.input);
  const inputPayload = input.exists ? tryParseJson(input.content) : null;
  const dispatchWrite = writeDispatchReceiptState(inputPayload);

  if ('content' in input) {
    delete input.content;
  }

  const response = {
    ok: true,
    tool: 'subagent_delivery_watchdog',
    version: 'skeleton-v2',
    mode: 'dispatch-receipt-write',
    args: {
      compact: args.compact,
      input: args.input,
    },
    input,
    result: {
      status: 'not_implemented',
      message: 'Dispatch receipt write is implemented; status recompute remains pending.',
      records: dispatchWrite ? [dispatchWrite.record] : [],
      dispatchReceiptWrite: dispatchWrite,
    },
  };

  const spacing = args.compact ? 0 : 2;
  process.stdout.write(`${JSON.stringify(response, null, spacing)}\n`);
}

main();