import crypto from 'node:crypto';
import fs from 'node:fs';
import fsPromises from 'node:fs/promises';
import path from 'node:path';
import {
  UPLOAD_ZONE_CODES,
  resolveUserWorkspaceRoot,
  resolveZoneDir,
} from './user-space.mjs';
import { resolveAssetWorkspaceRelativePath } from './mindspace-workspace-path.mjs';
import { assetInternals } from './mindspace-assets.mjs';
import { runBasicFileScan } from './mindspace-scan.mjs';
import { buildWorkspaceStorageKey } from './workspace-storage.mjs';

const SKIP_FILENAMES = new Set(['index.html', '.tkmindhints', '.goosehints', '.ls_output']);
const SKIP_ZONE_DIR_NAMES = new Set([
  'node_modules',
  '.venv',
  '.venv2',
  '__pycache__',
  '.git',
  'dist',
  'build',
  '.next',
  'target',
  'backend',
  'frontend',
]);
/** 子目录内常见的项目/脚手架文件，不同步到 OA 资产库 */
const NESTED_SKIP_BASENAMES = new Set([
  'README.md',
  'requirements.txt',
  'package.json',
  'package-lock.json',
  'pnpm-lock.yaml',
  'yarn.lock',
]);

function asNumber(value) {
  return Number(value ?? 0);
}

function generatedArtifactKindForMime(mimeType, filename) {
  const normalizedMime = String(mimeType ?? '').toLowerCase();
  const normalizedName = String(filename ?? '').toLowerCase();
  if (normalizedMime.startsWith('image/')) return 'generated_image';
  if (normalizedName.endsWith('.docx') || normalizedName.endsWith('.doc')) return 'docx';
  if (normalizedName.endsWith('.pdf')) return 'pdf';
  return 'generated_file';
}

function workspaceAssetDownloadUrl(assetId) {
  return `/api/mindspace/v1/assets/${encodeURIComponent(assetId)}/download`;
}

function scanOptionsForWorkspaceFile(categoryCode, filename, mimeType) {
  const normalizedName = String(filename ?? '').toLowerCase();
  if (
    categoryCode === 'public' &&
    mimeType === 'text/html' &&
    normalizedName.endsWith('.html')
  ) {
    return { htmlActiveContentPolicy: 'sandbox_warn' };
  }
  return {};
}

function assetStatusForScan(scan) {
  return scan.scanStatus === 'blocked' ? 'quarantined' : 'ready';
}

function versionStatusForScan(scan) {
  return scan.scanStatus === 'blocked' ? 'blocked' : scan.scanStatus;
}

export function normalizeWorkspaceRelativePath(relativePath) {
  const normalized = String(relativePath ?? '')
    .normalize('NFKC')
    .trim()
    .replace(/\\/g, '/');
  if (!normalized || normalized.startsWith('/') || normalized.includes('\0')) return null;
  const parts = normalized.split('/').filter(Boolean);
  if (parts.some((part) => part === '.' || part === '..')) return null;
  if (parts.some((part) => part.startsWith('.'))) return null;
  return parts.join('/').slice(0, 255);
}

export function shouldSyncWorkspaceFilename(filename) {
  const relativePath = normalizeWorkspaceRelativePath(filename);
  if (!relativePath) return false;
  const basename = path.posix.basename(relativePath);
  if (!basename || basename.startsWith('.')) return false;
  if (SKIP_FILENAMES.has(basename)) return false;
  if (basename.endsWith('.thumbnail.svg')) return false;
  if (basename.endsWith('.sh')) return false;
  if (relativePath.includes('/') && NESTED_SKIP_BASENAMES.has(basename)) return false;
  return assetInternals.expectedMimeType(basename) !== null;
}

async function walkWorkspaceZoneDir(zoneDir, relativePrefix, files) {
  let entries;
  try {
    entries = await fsPromises.readdir(zoneDir, { withFileTypes: true });
  } catch {
    return;
  }
  for (const entry of entries) {
    if (entry.name.startsWith('.')) continue;
    const absolutePath = path.join(zoneDir, entry.name);
    if (entry.isDirectory()) {
      if (SKIP_ZONE_DIR_NAMES.has(entry.name)) continue;
      const nextPrefix = relativePrefix ? `${relativePrefix}/${entry.name}` : entry.name;
      await walkWorkspaceZoneDir(absolutePath, nextPrefix, files);
      continue;
    }
    if (!entry.isFile()) continue;
    const filename = relativePrefix ? `${relativePrefix}/${entry.name}` : entry.name;
    if (!shouldSyncWorkspaceFilename(filename)) continue;
    const stat = await fsPromises.stat(absolutePath);
    files.push({
      filename,
      absolutePath,
      sizeBytes: stat.size,
      mtimeMs: stat.mtimeMs,
    });
  }
}

export async function listWorkspaceZoneFiles(workspaceRoot, categoryCode) {
  if (!UPLOAD_ZONE_CODES.includes(categoryCode)) return [];
  const zoneDir = resolveZoneDir(workspaceRoot, categoryCode);
  const files = [];
  await walkWorkspaceZoneDir(zoneDir, '', files);
  return files;
}

export function createWorkspaceAssetSync({
  pool,
  storageRoot,
  h5Root,
  maxFileBytes,
  idFactory,
  conversationPackageRegistry = null,
}) {
  void storageRoot;
  const loadExistingAssets = async (userId, categoryId) => {
    const [rows] = await pool.query(
      `SELECT a.id, a.original_filename, a.checksum, a.size_bytes, a.current_version_id, a.status
       FROM h5_assets a
       WHERE a.user_id = ? AND a.category_id = ? AND a.status <> 'deleted'`,
      [userId, categoryId],
    );
    return new Map(rows.map((row) => [row.original_filename, row]));
  };

  /** Skip re-importing workspace files the user already deleted (checksum unchanged). */
  const loadDeletedWorkspaceChecksums = async (userId, categoryId) => {
    const [rows] = await pool.query(
      `SELECT original_filename, checksum
       FROM h5_assets
       WHERE user_id = ? AND category_id = ? AND status = 'deleted' AND source_type = 'workspace'`,
      [userId, categoryId],
    );
    const byFilename = new Map();
    for (const row of rows) {
      const checksums = byFilename.get(row.original_filename) ?? new Set();
      checksums.add(row.checksum);
      byFilename.set(row.original_filename, checksums);
    }
    return byFilename;
  };

  const importWorkspaceFile = async (userId, category, file, buffer) => {
    const conn = await pool.getConnection();
    try {
      await conn.beginTransaction();
      const [spaces] = await conn.query(
        `SELECT id, quota_bytes, used_bytes, reserved_bytes, status
         FROM h5_user_spaces
         WHERE id = ? AND user_id = ?
         LIMIT 1
         FOR UPDATE`,
        [category.space_id, userId],
      );
      const space = spaces[0];
      if (!space || space.status !== 'active') {
        throw Object.assign(new Error('用户空间不可用'), { code: 'space_unavailable' });
      }
      const available =
        asNumber(space.quota_bytes) - asNumber(space.used_bytes) - asNumber(space.reserved_bytes);
      if (available < buffer.length) {
        throw Object.assign(new Error('剩余空间不足'), { code: 'quota_exceeded' });
      }

      const detectedMimeType = assetInternals.detectMimeType(buffer, file.filename);
      if (!detectedMimeType) {
        throw Object.assign(new Error('无法确认文件类型'), { code: 'unsupported_file_type' });
      }

      const scan = runBasicFileScan(buffer, {
        filename: file.filename,
        mimeType: detectedMimeType,
        ...scanOptionsForWorkspaceFile(category.category_code, file.filename, detectedMimeType),
      });
      const assetStatus = assetStatusForScan(scan);
      const versionScanStatus = versionStatusForScan(scan);
      const checksum = crypto.createHash('sha256').update(buffer).digest('hex');
      const assetId = idFactory();
      const versionId = idFactory();
      const finalStorageKey = buildWorkspaceStorageKey(
        userId,
        category.category_code,
        file.filename,
      );

      const now = Date.now();
      const visibility = category.category_code === 'public' ? 'public_candidate' : 'private';
      const indexedWorkspacePath = resolveAssetWorkspaceRelativePath({
        categoryCode: category.category_code,
        originalFilename: file.filename,
      });
      await conn.query(
        `INSERT INTO h5_assets
         (id, user_id, space_id, category_id, asset_type, mime_type, original_filename,
          display_name, workspace_relative_path, current_version_id, size_bytes, checksum, risk_level, visibility,
          status, source_type, created_at, updated_at)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'workspace', ?, ?)`,
        [
          assetId,
          userId,
          category.space_id,
          category.id,
          assetInternals.assetTypeForMime(detectedMimeType),
          detectedMimeType,
          file.filename,
          path.basename(file.filename, path.extname(file.filename)) || file.filename,
          indexedWorkspacePath,
          versionId,
          buffer.length,
          checksum,
          scan.riskLevel,
          visibility,
          assetStatus,
          now,
          now,
        ],
      );
      await conn.query(
        `INSERT INTO h5_asset_versions
         (id, asset_id, version_no, storage_key, size_bytes, checksum, mime_type,
          created_by, change_note, scan_status, created_at)
         VALUES (?, ?, 1, ?, ?, ?, ?, ?, '从工作区同步', ?, ?)`,
        [
          versionId,
          assetId,
          finalStorageKey,
          buffer.length,
          checksum,
          detectedMimeType,
          userId,
          versionScanStatus,
          now,
        ],
      );
      await conn.query(
        `UPDATE h5_user_spaces SET used_bytes = used_bytes + ?, updated_at = ?
         WHERE id = ? AND user_id = ?`,
        [buffer.length, now, category.space_id, userId],
      );
      await conn.commit();
      return {
        action: 'imported',
        assetId,
        filename: file.filename,
        checksum,
        mimeType: detectedMimeType,
        sizeBytes: buffer.length,
        storageKey: finalStorageKey,
        categoryCode: category.category_code,
      };
    } catch (error) {
      await conn.rollback();
      throw error;
    } finally {
      conn.release();
    }
  };

  const updateWorkspaceFile = async (userId, category, existing, file, buffer) => {
    const conn = await pool.getConnection();
    try {
      await conn.beginTransaction();
      const [spaces] = await conn.query(
        `SELECT id, quota_bytes, used_bytes, reserved_bytes, status
         FROM h5_user_spaces
         WHERE id = ? AND user_id = ?
         LIMIT 1
         FOR UPDATE`,
        [category.space_id, userId],
      );
      const space = spaces[0];
      if (!space || space.status !== 'active') {
        throw Object.assign(new Error('用户空间不可用'), { code: 'space_unavailable' });
      }
      const sizeDelta = buffer.length - asNumber(existing.size_bytes);
      const available =
        asNumber(space.quota_bytes) - asNumber(space.used_bytes) - asNumber(space.reserved_bytes);
      if (sizeDelta > 0 && available < sizeDelta) {
        throw Object.assign(new Error('剩余空间不足'), { code: 'quota_exceeded' });
      }

      const detectedMimeType = assetInternals.detectMimeType(buffer, file.filename);
      if (!detectedMimeType) {
        throw Object.assign(new Error('无法确认文件类型'), { code: 'unsupported_file_type' });
      }
      const scan = runBasicFileScan(buffer, {
        filename: file.filename,
        mimeType: detectedMimeType,
        ...scanOptionsForWorkspaceFile(category.category_code, file.filename, detectedMimeType),
      });
      const assetStatus = assetStatusForScan(scan);
      const versionScanStatus = versionStatusForScan(scan);
      const checksum = crypto.createHash('sha256').update(buffer).digest('hex');
      const [versionRows] = await conn.query(
        `SELECT COALESCE(MAX(version_no), 0) AS max_version
         FROM h5_asset_versions
         WHERE asset_id = ?`,
        [existing.id],
      );
      const versionNo = asNumber(versionRows[0]?.max_version) + 1;
      const versionId = idFactory();
      const finalStorageKey = buildWorkspaceStorageKey(
        userId,
        category.category_code,
        file.filename,
      );

      const now = Date.now();
      const indexedWorkspacePath = resolveAssetWorkspaceRelativePath({
        categoryCode: category.category_code,
        originalFilename: file.filename,
      });
      await conn.query(
        `UPDATE h5_assets
         SET current_version_id = ?, size_bytes = ?, checksum = ?, mime_type = ?,
             asset_type = ?, risk_level = ?, status = ?, workspace_relative_path = ?, updated_at = ?
         WHERE id = ? AND user_id = ?`,
        [
          versionId,
          buffer.length,
          checksum,
          detectedMimeType,
          assetInternals.assetTypeForMime(detectedMimeType),
          scan.riskLevel,
          assetStatus,
          indexedWorkspacePath,
          now,
          existing.id,
          userId,
        ],
      );
      await conn.query(
        `INSERT INTO h5_asset_versions
         (id, asset_id, version_no, storage_key, size_bytes, checksum, mime_type,
          created_by, change_note, scan_status, created_at)
         VALUES (?, ?, ?, ?, ?, ?, ?, ?, '工作区文件更新', ?, ?)`,
        [
          versionId,
          existing.id,
          versionNo,
          finalStorageKey,
          buffer.length,
          checksum,
          detectedMimeType,
          userId,
          versionScanStatus,
          now,
        ],
      );
      if (sizeDelta !== 0) {
        await conn.query(
          `UPDATE h5_user_spaces SET used_bytes = GREATEST(0, used_bytes + ?), updated_at = ?
           WHERE id = ? AND user_id = ?`,
          [sizeDelta, now, category.space_id, userId],
        );
      }
      await conn.commit();
      return {
        action: 'updated',
        assetId: existing.id,
        filename: file.filename,
        checksum,
        mimeType: detectedMimeType,
        sizeBytes: buffer.length,
        storageKey: finalStorageKey,
        categoryCode: category.category_code,
      };
    } catch (error) {
      await conn.rollback();
      throw error;
    } finally {
      conn.release();
    }
  };

  const registerWorkspaceArtifactForConversation = async (userId, source, result, now = Date.now()) => {
    const sessionId = String(source?.sessionId ?? source?.sourceSessionId ?? '').trim();
    if (!conversationPackageRegistry || !sessionId || !result?.assetId) return null;
    try {
      const packageRecord = await conversationPackageRegistry.ensurePackage({
        userId,
        sessionId,
        title: source?.title ?? null,
        now,
      });
      const artifact = await conversationPackageRegistry.recordArtifact({
        id: `ca_workspace_${result.assetId}`,
        packageId: packageRecord.id,
        artifactKind: generatedArtifactKindForMime(result.mimeType, result.filename),
        role: 'assistant',
        assetId: result.assetId,
        messageId: source?.messageId ?? source?.sourceMessageId ?? null,
        displayName: result.filename,
        mimeType: result.mimeType,
        sizeBytes: result.sizeBytes,
        storageKey: result.storageKey,
        canonicalUrl: workspaceAssetDownloadUrl(result.assetId),
        sortOrder: now,
        now,
      });
      await conversationPackageRegistry.writeManifestForSession({ userId, sessionId });
      return artifact;
    } catch (error) {
      console.warn('[MindSpace] workspace conversation artifact registration failed:', error?.message ?? error);
      return null;
    }
  };

  const syncCategory = async (userId, categoryCode, source = {}, { onlyRelativePaths = null } = {}) => {
    if (!h5Root) return { imported: 0, updated: 0, skipped: 0 };
    const workspaceRoot = resolveUserWorkspaceRoot(h5Root, { id: userId });
    let files = await listWorkspaceZoneFiles(workspaceRoot, categoryCode);
    if (onlyRelativePaths != null) {
      const allowed = new Set(
        onlyRelativePaths
          .map((item) => normalizeWorkspaceRelativePath(item))
          .filter(Boolean),
      );
      files = files.filter((file) =>
        allowed.has(normalizeWorkspaceRelativePath(`${categoryCode}/${file.filename}`)),
      );
    }
    const [categories] = await pool.query(
      `SELECT c.id, c.space_id, c.category_code
       FROM h5_space_categories c
       WHERE c.user_id = ? AND c.category_code = ?
       LIMIT 1`,
      [userId, categoryCode],
    );
    const category = categories[0];
    if (!category) return { imported: 0, updated: 0, skipped: 0 };

    const existingByName = await loadExistingAssets(userId, category.id);
    const deletedWorkspaceChecksums = await loadDeletedWorkspaceChecksums(userId, category.id);
    let imported = 0;
    let updated = 0;
    let skipped = 0;

    for (const file of files) {
      if (file.sizeBytes <= 0 || file.sizeBytes > maxFileBytes) {
        skipped += 1;
        continue;
      }
      const buffer = await fsPromises.readFile(file.absolutePath);
      const checksum = crypto.createHash('sha256').update(buffer).digest('hex');
      if (deletedWorkspaceChecksums.get(file.filename)?.has(checksum)) {
        skipped += 1;
        continue;
      }
      const existing = existingByName.get(file.filename);
      if (existing?.checksum === checksum) {
        skipped += 1;
        continue;
      }
      if (existing) {
        const result = await updateWorkspaceFile(userId, category, existing, file, buffer);
        await registerWorkspaceArtifactForConversation(userId, source, result);
        existing.checksum = checksum;
        updated += 1;
      } else {
        const result = await importWorkspaceFile(userId, category, file, buffer);
        await registerWorkspaceArtifactForConversation(userId, source, result);
        existingByName.set(file.filename, { checksum });
        imported += 1;
      }
    }
    return { imported, updated, skipped };
  };

  const syncUserWorkspace = async (
    userId,
    { categoryCode, sourceSessionId, sourceMessageId, title, onlyRelativePaths = null } = {},
  ) => {
    const codes = categoryCode ? [categoryCode] : UPLOAD_ZONE_CODES;
    let imported = 0;
    let updated = 0;
    let skipped = 0;
    const source = { sessionId: sourceSessionId, messageId: sourceMessageId, title };
    for (const code of codes) {
      const result = await syncCategory(userId, code, source, { onlyRelativePaths });
      imported += result.imported;
      updated += result.updated;
      skipped += result.skipped;
    }
    return { imported, updated, skipped };
  };

  return { syncUserWorkspace, syncCategory, listWorkspaceZoneFiles };
}

export const workspaceSyncInternals = {
  generatedArtifactKindForMime,
  workspaceAssetDownloadUrl,
};

export function startWorkspaceAssetSyncWatcher({ publishRoot, syncUserWorkspaceByDirKey }) {
  if (!publishRoot || !syncUserWorkspaceByDirKey) return () => {};

  const pending = new Map();
  const schedule = (dirKey, categoryCode) => {
    const key = `${dirKey}:${categoryCode ?? 'all'}`;
    const existing = pending.get(key);
    if (existing) clearTimeout(existing);
    pending.set(
      key,
      setTimeout(() => {
        pending.delete(key);
        void syncUserWorkspaceByDirKey(dirKey, categoryCode ? { categoryCode } : {}).catch(() => {});
      }, 600),
    );
  };

  const watchZoneDir = (dirKey, zoneDir, categoryCode) => {
    try {
      fs.watch(
        zoneDir,
        { recursive: true },
        (_event, filename) => {
          if (!filename) {
            schedule(dirKey, categoryCode);
            return;
          }
          const normalized = String(filename).replace(/\\/g, '/');
          if (shouldSyncWorkspaceFilename(normalized)) {
            schedule(dirKey, categoryCode);
          }
        },
      );
    } catch {
      // ignore unsupported watch targets
    }
  };

  const attachUser = async (dirKey) => {
    const userDir = path.join(publishRoot, dirKey);
    try {
      await fsPromises.access(userDir);
    } catch {
      return;
    }
    for (const categoryCode of UPLOAD_ZONE_CODES) {
      watchZoneDir(dirKey, resolveZoneDir(userDir, categoryCode), categoryCode);
    }
  };

  for (const entry of fs.readdirSync(publishRoot, { withFileTypes: true })) {
    if (!entry.isDirectory() || entry.name === 'wiki' || entry.name.startsWith('.')) continue;
    void attachUser(entry.name);
  }

  try {
    fs.watch(publishRoot, (_event, filename) => {
      if (!filename) return;
      const userDir = path.join(publishRoot, filename);
      if (fs.existsSync(userDir) && fs.statSync(userDir).isDirectory()) {
        void attachUser(filename);
      }
    });
  } catch {
    // ignore
  }

  return () => {
    for (const timer of pending.values()) clearTimeout(timer);
    pending.clear();
  };
}