#!/usr/bin/env node
// @ts-nocheck

import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = path.dirname(fileURLToPath(import.meta.url));

const SCOPES = new Set(['aggressive']);

function usage() {
  console.error(
    [
      'Usage: cleanup-copilot-history.mjs [options]',
      '',
      'Options:',
      '  --audit-dir <path>           Audit directory used as completion boundary context.',
      '  --completion-cutoff <iso>    Delete targets with mtime at or before this timestamp.',
      '  --scope <scope>              Cleanup scope. Supported: aggressive. Default: aggressive',
      '  --quarantine-dir <path>      Override quarantine root directory.',
      '  --repo-root <path>           Override repository root.',
      '  --execute                    Perform cleanup. Default is dry-run.',
      '  --help                       Show this help text.',
    ].join('\n'),
  );
}

function parseArgs(argv) {
  const options = {
    auditDir: '',
    completionCutoff: '',
    execute: false,
    scope: 'aggressive',
    repoRoot: path.resolve(__dirname, '../..'),
    quarantineDir: path.join(
      os.homedir(),
      '.copilot-resources-state',
      'quarantine',
      'copilot-history-cleanup',
    ),
  };

  for (let index = 0; index < argv.length; index += 1) {
    const arg = argv[index];
    if (arg === '--help' || arg === '-h') {
      usage();
      process.exit(0);
    }
    if (arg === '--audit-dir') {
      options.auditDir = path.resolve(argv[index + 1] ?? '');
      index += 1;
      continue;
    }
    if (arg === '--completion-cutoff') {
      options.completionCutoff = argv[index + 1] ?? '';
      index += 1;
      continue;
    }
    if (arg === '--scope') {
      options.scope = argv[index + 1] ?? options.scope;
      index += 1;
      continue;
    }
    if (arg === '--quarantine-dir') {
      options.quarantineDir = path.resolve(argv[index + 1] ?? options.quarantineDir);
      index += 1;
      continue;
    }
    if (arg === '--repo-root') {
      options.repoRoot = path.resolve(argv[index + 1] ?? options.repoRoot);
      index += 1;
      continue;
    }
    if (arg === '--execute') {
      options.execute = true;
      continue;
    }

    throw new Error(`Unknown argument: ${arg}`);
  }

  if (!SCOPES.has(options.scope)) {
    throw new Error(`Unsupported scope: ${options.scope}`);
  }

  return options;
}

function ensureDir(dirPath) {
  fs.mkdirSync(dirPath, { recursive: true });
}

function safeStat(filePath) {
  try {
    return fs.statSync(filePath);
  } catch {
    return null;
  }
}

function listDirs(rootPath) {
  if (!fs.existsSync(rootPath)) {
    return [];
  }

  return fs.readdirSync(rootPath, { withFileTypes: true })
    .filter((entry) => entry.isDirectory())
    .map((entry) => path.join(rootPath, entry.name));
}

function findLatestAuditDir(repoRoot) {
  const auditRoot = path.join(repoRoot, '.local', 'audits');
  const dirs = [];

  for (const firstLevel of listDirs(auditRoot)) {
    if (safeStat(path.join(firstLevel, 'selection-manifest.tsv'))) {
      dirs.push(firstLevel);
      continue;
    }

    for (const secondLevel of listDirs(firstLevel)) {
      if (safeStat(path.join(secondLevel, 'selection-manifest.tsv'))) {
        dirs.push(secondLevel);
      }
    }
  }

  let latest = null;
  for (const dirPath of dirs) {
    const stat = safeStat(dirPath);
    if (!stat) {
      continue;
    }
    if (!latest || stat.mtimeMs > latest.mtimeMs) {
      latest = { path: dirPath, mtimeMs: stat.mtimeMs };
    }
  }

  return latest?.path ?? null;
}

function resolveCutoffMs(options, auditDir) {
  if (options.completionCutoff) {
    const parsed = Date.parse(options.completionCutoff);
    if (Number.isNaN(parsed)) {
      throw new Error(`Invalid --completion-cutoff timestamp: ${options.completionCutoff}`);
    }
    return parsed;
  }

  const summaryPath = path.join(auditDir, 'promotion-summary.md');
  const summaryStat = safeStat(summaryPath);
  if (summaryStat) {
    return summaryStat.mtimeMs;
  }

  const auditStat = safeStat(auditDir);
  if (auditStat) {
    return auditStat.mtimeMs;
  }

  return Date.now();
}

function normalizePath(filePath) {
  return path.resolve(filePath);
}

function pathIsInside(candidatePath, parentPath) {
  const relativePath = path.relative(parentPath, candidatePath);
  return relativePath === '' || (!relativePath.startsWith('..') && !path.isAbsolute(relativePath));
}

function collectAuditRunTargets(repoRoot, currentAuditDir, cutoffMs) {
  const auditRoot = path.join(repoRoot, '.local', 'audits');
  const candidates = [];

  for (const firstLevel of listDirs(auditRoot)) {
    const nested = listDirs(firstLevel);
    if (safeStat(path.join(firstLevel, 'selection-manifest.tsv'))) {
      nested.push(firstLevel);
    }

    for (const runDir of nested) {
      const manifestPath = path.join(runDir, 'selection-manifest.tsv');
      if (!safeStat(manifestPath)) {
        continue;
      }

      const normalizedRunDir = normalizePath(runDir);
      if (normalizedRunDir === currentAuditDir) {
        continue;
      }

      const runStat = safeStat(runDir);
      if (!runStat) {
        continue;
      }

      if (runStat.mtimeMs > cutoffMs) {
        continue;
      }

      candidates.push({
        path: normalizedRunDir,
        category: 'audit-run',
        reason: 'Historical audit run older than completion cutoff.',
        mtimeMs: runStat.mtimeMs,
      });
    }
  }

  return candidates;
}

function collectWorkspaceTargets(cutoffMs) {
  const workspaceRoot = path.join(
    os.homedir(),
    'Library',
    'Application Support',
    'Code',
    'User',
    'workspaceStorage',
  );

  const relativeTargets = [
    'chatSessions',
    'chatEditingSessions',
    path.join('GitHub.copilot-chat', 'transcripts'),
    path.join('GitHub.copilot-chat', 'chat-session-resources'),
  ];

  const candidates = [];

  for (const workspaceDir of listDirs(workspaceRoot)) {
    for (const relativeTarget of relativeTargets) {
      const absoluteTarget = path.join(workspaceDir, relativeTarget);
      const targetStat = safeStat(absoluteTarget);
      if (!targetStat || !targetStat.isDirectory()) {
        continue;
      }

      if (targetStat.mtimeMs > cutoffMs) {
        continue;
      }

      candidates.push({
        path: normalizePath(absoluteTarget),
        category: 'workspace-history',
        reason: 'Copilot or chat history artifact older than completion cutoff.',
        mtimeMs: targetStat.mtimeMs,
      });
    }
  }

  return candidates;
}

function dedupeNestedTargets(targets) {
  const sorted = [...targets].sort((left, right) => left.path.localeCompare(right.path));
  const result = [];

  for (const target of sorted) {
    const parentAlreadySelected = result.some((existing) => pathIsInside(target.path, existing.path));
    if (!parentAlreadySelected) {
      result.push(target);
    }
  }

  return result;
}

function formatBytes(bytes) {
  const units = ['B', 'KB', 'MB', 'GB', 'TB'];
  let value = Number(bytes) || 0;
  let unitIndex = 0;
  while (value >= 1024 && unitIndex < units.length - 1) {
    value /= 1024;
    unitIndex += 1;
  }
  return `${value.toFixed(unitIndex === 0 ? 0 : 2)} ${units[unitIndex]}`;
}

function measureSize(filePath) {
  const stat = safeStat(filePath);
  if (!stat) {
    return 0;
  }
  if (stat.isFile()) {
    return stat.size;
  }
  if (!stat.isDirectory()) {
    return 0;
  }

  let total = 0;
  const entries = fs.readdirSync(filePath, { withFileTypes: true });
  for (const entry of entries) {
    const childPath = path.join(filePath, entry.name);
    if (entry.isDirectory()) {
      total += measureSize(childPath);
    } else if (entry.isFile()) {
      const childStat = safeStat(childPath);
      total += childStat?.size ?? 0;
    }
  }

  return total;
}

function quarantineRelativePath(targetPath) {
  const relativeToRoot = path.relative(path.parse(targetPath).root, targetPath);
  return relativeToRoot.replace(/:/g, '_');
}

function moveToQuarantine(targetPath, quarantineRoot) {
  const destinationPath = path.join(quarantineRoot, quarantineRelativePath(targetPath));
  ensureDir(path.dirname(destinationPath));

  try {
    fs.renameSync(targetPath, destinationPath);
  } catch (error) {
    if (error?.code !== 'EXDEV') {
      throw error;
    }
    fs.cpSync(targetPath, destinationPath, { recursive: true });
    fs.rmSync(targetPath, { recursive: true, force: true });
  }

  return destinationPath;
}

function writeQuarantineManifest(quarantineRunDir, results) {
  const manifestPath = path.join(quarantineRunDir, 'manifest.json');
  const rows = results
    .filter((result) => result.status === 'quarantined' && result.destination)
    .map((result) => ({
      originalPath: result.path,
      quarantinePath: result.destination,
      bytes: result.bytes,
      reason: result.reason,
    }));
  fs.writeFileSync(manifestPath, `${JSON.stringify({ createdAt: new Date().toISOString(), rows }, null, 2)}\n`, 'utf8');
  return manifestPath;
}

function writeSummary({
  auditDir,
  execute,
  scope,
  cutoffMs,
  quarantineRunDir,
  targets,
  results,
  totalBytes,
}) {
  const summaryPath = path.join(auditDir, 'cleanup-summary.md');
  const lines = [
    '# Copilot History Cleanup Summary',
    '',
    `- Generated: ${new Date().toISOString()}`,
    `- Mode: ${execute ? 'execute' : 'dry-run'}`,
    `- Scope: ${scope}`,
    `- Completion cutoff: ${new Date(cutoffMs).toISOString()}`,
    `- Targets discovered: ${targets.length}`,
    `- Targets processed: ${results.filter((entry) => entry.status === 'quarantined').length}`,
    `- Targets skipped: ${results.filter((entry) => entry.status === 'skipped').length}`,
    `- Targets failed: ${results.filter((entry) => entry.status === 'failed').length}`,
    `- Estimated bytes affected: ${formatBytes(totalBytes)}`,
    `- Quarantine directory: ${quarantineRunDir}`,
    '',
    '## Results',
    '',
  ];

  if (results.length === 0) {
    lines.push('- None');
  } else {
    for (const result of results) {
      const sizeText = result.bytes > 0 ? ` (${formatBytes(result.bytes)})` : '';
      const destinationText = result.destination ? ` -> ${result.destination}` : '';
      lines.push(`- [${result.status}] ${result.path}${sizeText}${destinationText}`);
      if (result.message) {
        lines.push(`  - ${result.message}`);
      }
      if (result.reason) {
        lines.push(`  - Reason: ${result.reason}`);
      }
    }
  }

  fs.writeFileSync(summaryPath, `${lines.join('\n')}\n`, 'utf8');
  return summaryPath;
}

export function runCleanup(rawOptions) {
  const options = {
    ...rawOptions,
    repoRoot: path.resolve(rawOptions.repoRoot),
    auditDir: rawOptions.auditDir ? path.resolve(rawOptions.auditDir) : '',
    quarantineDir: path.resolve(rawOptions.quarantineDir),
  };

  const auditDir = options.auditDir || findLatestAuditDir(options.repoRoot);
  if (!auditDir) {
    throw new Error('No audit directory was found. Run the audit first or pass --audit-dir.');
  }

  const currentAuditDir = normalizePath(auditDir);
  const cutoffMs = resolveCutoffMs(options, currentAuditDir);
  const discoveredTargets = dedupeNestedTargets([
    ...collectAuditRunTargets(options.repoRoot, currentAuditDir, cutoffMs),
    ...collectWorkspaceTargets(cutoffMs),
  ]);

  const runLabel = new Date().toISOString().replace(/[:.]/g, '-');
  const quarantineRunDir = path.join(options.quarantineDir, runLabel);
  const results = [];
  let totalBytes = 0;

  if (options.execute) {
    ensureDir(quarantineRunDir);
  }

  for (const target of discoveredTargets) {
    const bytes = measureSize(target.path);
    totalBytes += bytes;

    if (!options.execute) {
      results.push({
        status: 'skipped',
        path: target.path,
        bytes,
        reason: target.reason,
        message: 'Dry-run: no changes were applied.',
      });
      continue;
    }

    try {
      const destination = moveToQuarantine(target.path, quarantineRunDir);
      results.push({
        status: 'quarantined',
        path: target.path,
        destination,
        bytes,
        reason: target.reason,
      });
    } catch (error) {
      results.push({
        status: 'failed',
        path: target.path,
        bytes,
        reason: target.reason,
        message: error?.message || String(error),
      });
    }
  }

  let manifestPath = '';
  if (options.execute) {
    manifestPath = writeQuarantineManifest(quarantineRunDir, results);
  }

  const summaryPath = writeSummary({
    auditDir: currentAuditDir,
    execute: options.execute,
    scope: options.scope,
    cutoffMs,
    quarantineRunDir,
    targets: discoveredTargets,
    results,
    totalBytes,
  });

  return {
    auditDir: currentAuditDir,
    cutoffIso: new Date(cutoffMs).toISOString(),
    targetsDiscovered: discoveredTargets.length,
    processed: results.filter((entry) => entry.status === 'quarantined').length,
    failed: results.filter((entry) => entry.status === 'failed').length,
    summaryPath,
    manifestPath,
    quarantineRunDir,
  };
}

function main() {
  const options = parseArgs(process.argv.slice(2));
  const result = runCleanup(options);

  console.log('Copilot history cleanup complete.');
  console.log(`Audit directory: ${result.auditDir}`);
  console.log(`Completion cutoff: ${result.cutoffIso}`);
  console.log(`Targets discovered: ${result.targetsDiscovered}`);
  console.log(`Targets quarantined: ${result.processed}`);
  console.log(`Targets failed: ${result.failed}`);
  console.log(`Quarantine directory: ${result.quarantineRunDir}`);
  if (result.manifestPath) {
    console.log(`Manifest: ${result.manifestPath}`);
  }
  console.log(`Summary: ${result.summaryPath}`);
}

const isMainModule = process.argv[1] && path.resolve(process.argv[1]) === fileURLToPath(import.meta.url);
if (isMainModule) {
  main();
}