import { existsSync, readdirSync, rmSync, statSync } from 'node:fs';
import path from 'node:path';

import type { CleanupHistoryInput, CleanupProcessPlanInput } from '../types.js';
import { defaultHistoryRoots } from '../core/constants.js';
import { resolveInsideRoot, resolveProject, toPosix, workspaceRoot } from '../core/workspace.js';
export function createCleanupProcessPlan(input: CleanupProcessPlanInput): Record<string, unknown> {
  const project = resolveProject(input.project);
  const escapedProjectPath = project.path.replaceAll('\\', '\\\\');
  const portFilters = (input.ports || []).map((port) => ({
    command: `Get-NetTCPConnection -LocalPort ${port} -ErrorAction SilentlyContinue | Select-Object -ExpandProperty OwningProcess -Unique`,
    port,
  }));

  return {
    commands: [
      `Get-CimInstance Win32_Process | Where-Object { $_.CommandLine -like '*${escapedProjectPath}*' -and $_.Name -match 'node|pnpm|npm|yarn' } | Select-Object ProcessId,Name,CommandLine`,
      '确认命中进程只属于本次验证后，再用 Stop-Process -Id <pid> 结束。',
      ...portFilters.map((item) => item.command),
    ],
    notes: [
      '先按项目路径筛选，再按端口交叉确认。',
      '不要批量结束与本次验证无关的 Node 进程。',
      '页面测试结束后清理浏览器和 Vite/Nest 进程，避免内存累积。',
    ],
    project,
  };
}

interface HistoryEntry {
  lastWriteTime: string;
  mtimeMs: number;
  name: string;
  path: string;
  relativePath: string;
  type: 'directory' | 'file';
}

const workspaceRootPreservedNames = new Set([
  'backup',
  'db-sync',
  'deploy',
  'exports',
  'live2d-pio',
  'logs',
  'playwright-mcp',
  'subagents',
  'test-artifacts',
  'test-logs',
  'tmp',
  'verify',
]);

const live2dPioPreservedNames = new Set([
  '.venv',
  'moc-reconstruction',
  'moc-runtime',
  'probe-source-wordpress-parity',
  'runtime-export-moc-driven',
  'runtime-publish',
  'sources',
  'vendor',
]);

/**
 * Builds the directory names that represent generated artifact categories under
 * `.kt-workspace`; test artifact templates stay in place because KT page and
 * business test flows use them as local scaffolding inputs.
 *
 * @param rootRelativePath - Cleanup root relative to the KT workspace.
 * @returns Category names that cleanup should skip when pruning `.kt-workspace`.
 */
function buildPreservedNames(rootRelativePath: string): Set<string> {
  const preservedNames = new Set<string>();

  if (rootRelativePath === '.kt-workspace') {
    for (const name of workspaceRootPreservedNames) {
      preservedNames.add(name);
    }
  }
  if (rootRelativePath === '.kt-workspace/test-artifacts') {
    preservedNames.add('_templates');
  }
  if (rootRelativePath === '.kt-workspace/live2d-pio') {
    for (const name of live2dPioPreservedNames) {
      preservedNames.add(name);
    }
  }

  return preservedNames;
}

/**
 * Finds the latest write time anywhere inside one history entry.
 *
 * Windows does not reliably update a directory's own mtime when an existing
 * descendant file is rewritten, so cleanup ordering must include descendant
 * activity or it can delete a currently active evidence tree.
 *
 * @param entryPath - File or directory being ranked for retention.
 * @param isDirectory - Whether the entry may contain nested artifacts.
 * @returns Latest mtime in milliseconds across the entry and its descendants.
 */
function getLatestEntryMtimeMs(entryPath: string, isDirectory: boolean): number {
  let latestMtimeMs = statSync(entryPath).mtimeMs;
  if (!isDirectory) return latestMtimeMs;

  for (const child of readdirSync(entryPath, { withFileTypes: true })) {
    const childPath = path.join(entryPath, child.name);
    latestMtimeMs = Math.max(
      latestMtimeMs,
      getLatestEntryMtimeMs(childPath, child.isDirectory()),
    );
  }
  return latestMtimeMs;
}

function listHistoryEntries(rootPath: string, preservedNames: Set<string>): HistoryEntry[] {
  if (!existsSync(rootPath)) return [];

  return readdirSync(rootPath, { withFileTypes: true })
    .filter((item) => !preservedNames.has(item.name))
    .map((item) => {
      const entryPath = path.join(rootPath, item.name);
      const isDirectory = item.isDirectory();
      const mtimeMs = getLatestEntryMtimeMs(entryPath, isDirectory);

      return {
        lastWriteTime: new Date(mtimeMs).toISOString(),
        mtimeMs,
        name: item.name,
        path: entryPath,
        relativePath: toPosix(path.relative(workspaceRoot, entryPath)),
        type: isDirectory ? ('directory' as const) : ('file' as const),
      };
    })
    .sort((a, b) => b.mtimeMs - a.mtimeMs);
}

export function cleanupHistoryArtifacts(input: CleanupHistoryInput = {}): Record<string, unknown> {
  const keep = Math.max(0, Math.min(input.keep ?? 3, 50));
  const dryRun = input.dryRun ?? true;
  const roots = (input.roots?.length ?? 0) > 0 ? input.roots! : [...defaultHistoryRoots];
  const result = {
    deleted: [] as Array<Omit<HistoryEntry, 'mtimeMs' | 'path'>>,
    dryRun,
    keep,
    preserved: [] as Array<Omit<HistoryEntry, 'mtimeMs' | 'path'>>,
    roots: [] as Array<{
      candidates: number;
      deleteCount: number;
      keepCount: number;
      preservedNames: string[];
      root: string;
    }>,
    skipped: [] as Array<{
      reason: string;
      root: string;
    }>,
  };

  for (const root of roots) {
    const rootPath = resolveInsideRoot(root);
    const rootRelativePath = toPosix(path.relative(workspaceRoot, rootPath)) || '.';

    if (!existsSync(rootPath)) {
      result.skipped.push({
        reason: 'not_exists',
        root: rootRelativePath,
      });
      continue;
    }

    const preservedNames = buildPreservedNames(rootRelativePath);
    const entries = listHistoryEntries(rootPath, preservedNames);
    const preserved = entries.slice(0, keep);
    const deleting = entries.slice(keep);

    result.roots.push({
      candidates: entries.length,
      deleteCount: deleting.length,
      keepCount: preserved.length,
      preservedNames: Array.from(preservedNames),
      root: rootRelativePath,
    });
    result.preserved.push(...preserved.map(({ mtimeMs, path: _path, ...entry }) => entry));

    for (const entry of deleting) {
      if (!dryRun) {
        rmSync(entry.path, {
          force: true,
          recursive: true,
        });
      }
      const { mtimeMs, path: _path, ...publicEntry } = entry;
      result.deleted.push(publicEntry);
    }
  }

  return result;
}

export function parseCliCleanupArgs(args: string[]): CleanupHistoryInput {
  const keepArg = args.find((arg) => arg.startsWith('--keep='));
  const rootsArg = args.find((arg) => arg.startsWith('--roots='));

  return {
    dryRun: !(args.includes('--execute') || args.includes('--no-dry-run')),
    keep: keepArg ? Number.parseInt(keepArg.split('=')[1], 10) : 3,
    roots: rootsArg ? rootsArg.split('=')[1].split(',').filter(Boolean) : [...defaultHistoryRoots],
  };
}