import { Injectable } from '@nestjs/common';
import Database from 'better-sqlite3';
import fs from 'fs';
import path from 'path';
import { MigrationRunner } from './migration-runner';

@Injectable()
export class DbService {
  private db: Database.Database;

  constructor() {
    // Use unified database for all settings/configuration
    // Find project root by traversing up from current directory until we find the root package.json
    let projectRoot = process.cwd();
    while (projectRoot !== path.dirname(projectRoot)) {
      if (fs.existsSync(path.join(projectRoot, 'package.json'))) {
        try {
          const pkg = JSON.parse(
            fs.readFileSync(path.join(projectRoot, 'package.json'), 'utf-8'),
          );
          if (pkg.name === 'watch-finished-turbo') {
            break;
          }
        } catch (e) {
          // ignore
        }
      }
      projectRoot = path.dirname(projectRoot);
    }

    const rootDataPath = path.resolve(projectRoot, 'data/database.db');

    // Ensure the directory exists
    const dir = path.dirname(rootDataPath);

    if (!fs.existsSync(dir)) {
      fs.mkdirSync(dir, { recursive: true });
    }

    try {
      this.db = new Database(rootDataPath);

      // Run migrations
      const migrationsDir = path.resolve(projectRoot, 'data/migrations');
      const migrationRunner = new MigrationRunner(this.db, migrationsDir);
      migrationRunner.applyPendingMigrations();
    } catch (error) {
      console.error('Failed to open database:', error);
      console.error('Database path:', rootDataPath);
      console.error('Directory exists:', fs.existsSync(dir));
      console.error(
        'Directory permissions:',
        fs.statSync(dir).mode.toString(8),
      );
      throw error;
    }
  }

  /**
   * Get the database instance for direct queries
   */
  getDb(): Database.Database {
    return this.db;
  }

  // List all files
  listAllFiles() {
    return this.db.prepare('SELECT * FROM files').all();
  }

  // List all files for a dataset
  listFilesForDataset(dataset: string) {
    return this.db
      .prepare('SELECT * FROM files WHERE dataset = ?')
      .all(dataset);
  }

  /**
   * Delete file records older than X days (autoExpireDays from settings)
   * @param days Days to keep (optional, overrides settings)
   */
  deleteExpiredFiles(days?: number): number {
    // Fallback to 180 if no settings available
    const keepDays = days || 180;
    const cutoff = new Date(
      Date.now() - keepDays * 24 * 60 * 60 * 1000,
    ).toISOString();
    const stmt = this.db.prepare('DELETE FROM files WHERE date < ?');
    const info = stmt.run(cutoff);
    return info.changes;
  }

  /**
   * Migrate legacy JSON files to the SQLite database.
   * @param opts Options for migration.
   * @param dbOverride Optional override for db instance.
   */
  migrateJsonToSqlite(
    opts: { datasets?: string[]; dataDir?: string } = {},
    dbOverride?: Database.Database,
  ) {
    const datasets = opts.datasets || [
      'movies',
      'tvshows',
      'kids',
      'pr0n',
      'sports',
    ];
    const dataDir = opts.dataDir || path.join(process.cwd(), 'legacy/data');
    const dbInstance = dbOverride || this.db;

    dbInstance.exec(`
      CREATE TABLE IF NOT EXISTS files (
        dataset TEXT,
        input TEXT,
        output TEXT,
        date TEXT,
        status TEXT DEFAULT 'pending',
        PRIMARY KEY (dataset, input)
      );
    `);

    const insert = dbInstance.prepare(
      'INSERT INTO files (dataset, input, output, date) VALUES (?, ?, ?, ?)',
    );
    for (const dataset of datasets) {
      const filePath = path.join(dataDir, `${dataset}.json`);
      if (!fs.existsSync(filePath)) continue;
      const json = JSON.parse(fs.readFileSync(filePath, 'utf8'));
      if (!json.files || !Array.isArray(json.files)) continue;
      for (const rec of json.files) {
        insert.run(
          dataset,
          rec.input || null,
          rec.output || null,
          rec.date || null,
        );
      }
    }
  }

  // Duplicate file review helpers
  clearDuplicateGroups() {
    this.db.prepare('DELETE FROM duplicate_files').run();
  }

  getDuplicateGroup(id: number) {
    const row = this.db
      .prepare('SELECT * FROM duplicate_files WHERE id = ?')
      .get(id) as
      | {
          id: number;
          dataset: string;
          destination: string;
          hash: string;
          size: number;
          files: string;
          status: string;
          note?: string;
          created_at: string;
          reviewed_at?: string;
        }
      | undefined;

    if (!row) return undefined;
    return { ...row, files: this.safeParseFiles(row.files) };
  }

  getDuplicateGroupByKey(
    dataset: string,
    destination: string,
    hash: string,
    size: number,
  ) {
    const row = this.db
      .prepare(
        'SELECT * FROM duplicate_files WHERE dataset = ? AND destination = ? AND hash = ? AND size = ?',
      )
      .get(dataset, destination, hash, size) as
      | {
          id: number;
          dataset: string;
          destination: string;
          hash: string;
          size: number;
          files: string;
          status: string;
          note?: string;
          created_at: string;
          reviewed_at?: string;
        }
      | undefined;

    if (!row) return undefined;
    return { ...row, files: this.safeParseFiles(row.files) };
  }

  saveDuplicateGroup(entry: {
    dataset: string;
    destination: string;
    hash: string;
    size: number;
    files: string[];
  }) {
    const existing = this.getDuplicateGroupByKey(
      entry.dataset,
      entry.destination,
      entry.hash,
      entry.size,
    );

    // Do not re-flag entries that were manually reviewed/ignored
    if (existing && existing.status === 'reviewed') {
      return existing;
    }

    const filesJson = JSON.stringify(entry.files);

    if (existing) {
      this.db
        .prepare(
          `UPDATE duplicate_files
           SET files = ?, size = ?, status = 'pending', note = note, reviewed_at = NULL
           WHERE id = ?`,
        )
        .run(filesJson, entry.size, existing.id);
      return {
        ...existing,
        files: entry.files,
        size: entry.size,
        status: 'pending',
      };
    }

    const result = this.db
      .prepare(
        `INSERT INTO duplicate_files (dataset, destination, hash, size, files)
         VALUES (?, ?, ?, ?, ?)`,
      )
      .run(entry.dataset, entry.destination, entry.hash, entry.size, filesJson);

    return {
      ...entry,
      id: result.lastInsertRowid as number,
      status: 'pending',
      note: null,
    };
  }

  listDuplicateGroups(status?: string, dataset?: string) {
    let query = 'SELECT * FROM duplicate_files';
    const params: any[] = [];

    if (status) {
      query += ' WHERE status = ?';
      params.push(status);
    }

    if (dataset) {
      query += status ? ' AND dataset = ?' : ' WHERE dataset = ?';
      params.push(dataset);
    }

    query += ' ORDER BY created_at DESC';

    const rows = this.db.prepare(query).all(...params) as Array<{
      id: number;
      dataset: string;
      destination: string;
      hash: string;
      size: number;
      files: string;
      status: string;
      note?: string;
      created_at: string;
      reviewed_at?: string;
    }>;

    return rows.map((row) => ({
      ...row,
      files: this.safeParseFiles(row.files),
    }));
  }

  markDuplicateGroup(
    id: number,
    status: 'pending' | 'reviewed' | 'purged',
    note?: string,
  ) {
    return this.db
      .prepare(
        `UPDATE duplicate_files
         SET status = ?, note = COALESCE(?, note), reviewed_at = CURRENT_TIMESTAMP
         WHERE id = ?`,
      )
      .run(status, note || null, id);
  }

  updateDuplicateGroupFiles(
    id: number,
    files: string[],
    status?: 'pending' | 'reviewed' | 'purged',
    note?: string,
  ) {
    return this.db
      .prepare(
        `UPDATE duplicate_files
         SET files = ?,
             status = COALESCE(?, status),
             note = COALESCE(?, note),
             reviewed_at = CASE WHEN ? IS NOT NULL THEN CURRENT_TIMESTAMP ELSE reviewed_at END
         WHERE id = ?`,
      )
      .run(
        JSON.stringify(files),
        status || null,
        note || null,
        status || null,
        id,
      );
  }

  deleteDuplicateGroup(id: number) {
    return this.db.prepare('DELETE FROM duplicate_files WHERE id = ?').run(id);
  }

  private safeParseFiles(value: string): string[] {
    try {
      const parsed = JSON.parse(value);
      return Array.isArray(parsed) ? parsed : [];
    } catch {
      return [];
    }
  }

  findFile(dataset: string, file: string) {
    return this.db
      .prepare('SELECT * FROM files WHERE dataset = ? AND input = ?')
      .get(dataset, file);
  }

  setFile(dataset: string, file: string, payload: any) {
    const existing = this.findFile(dataset, file) as
      | {
          dataset: string;
          input: string;
          output?: string;
          date?: string;
          status?: string;
          hash?: string;
          file_size?: number;
        }
      | undefined;

    const outputValue =
      payload && payload.output !== undefined
        ? payload.output
        : (existing?.output ?? null);

    const statusValue =
      payload && payload.status !== undefined
        ? payload.status
        : (existing?.status ?? 'pending');

    const dateValue =
      payload && payload.date !== undefined
        ? new Date(payload.date).toISOString()
        : existing?.date || new Date().toISOString();

    const hashValue =
      payload && payload.hash !== undefined
        ? payload.hash
        : (existing?.hash ?? null);

    const fileSizeValue =
      payload && payload.file_size !== undefined
        ? payload.file_size
        : (existing?.file_size ?? null);

    if (existing) {
      this.db
        .prepare(
          `UPDATE files
           SET output = COALESCE(?, output),
               date = COALESCE(?, date),
               status = COALESCE(?, status),
               hash = COALESCE(?, hash),
               file_size = COALESCE(?, file_size)
           WHERE dataset = ? AND input = ?`,
        )
        .run(
          outputValue,
          dateValue,
          statusValue,
          hashValue,
          fileSizeValue,
          dataset,
          file,
        );
    } else {
      this.db
        .prepare(
          'INSERT INTO files (dataset, input, output, date, status, hash, file_size) VALUES (?, ?, ?, ?, ?, ?, ?)',
        )
        .run(
          dataset,
          file,
          outputValue,
          dateValue,
          statusValue,
          hashValue,
          fileSizeValue,
        );
    }

    return this.findFile(dataset, file);
  }

  removeFile(dataset: string, file: string, soft = true) {
    if (soft) {
      this.db
        .prepare(
          'UPDATE files SET status = ?, date = ? WHERE dataset = ? AND input = ?',
        )
        .run('deleted', new Date().toISOString(), dataset, file);
    } else {
      this.db
        .prepare('DELETE FROM files WHERE dataset = ? AND input = ?')
        .run(dataset, file);
    }
  }

  clearAllFiles() {
    this.db.prepare('DELETE FROM files').run();
  }

  getAllFiles(dataset: string) {
    return this.db
      .prepare('SELECT * FROM files WHERE dataset = ?')
      .all(dataset);
  }

  getDeletedOlderThan(dataset: string, isoDate: string) {
    return this.db
      .prepare('SELECT * FROM files WHERE dataset = ? AND date < ?')
      .all(dataset, isoDate);
  }

  // Task CRUD methods
  getAllTasks() {
    return this.db
      .prepare('SELECT * FROM tasks ORDER BY created_at DESC')
      .all();
  }

  getPendingTasks(limit: number = 10) {
    return this.db
      .prepare(
        'SELECT * FROM tasks WHERE status = ? ORDER BY priority DESC, created_at ASC LIMIT ?',
      )
      .all('pending', limit);
  }

  getTaskById(id: number) {
    return this.db.prepare('SELECT * FROM tasks WHERE id = ?').get(id);
  }

  getTaskByInput(input: string) {
    return this.db.prepare('SELECT * FROM tasks WHERE input = ?').get(input);
  }

  createTask(task: {
    type: string;
    status?: string;
    progress?: number;
    dataset?: string;
    input?: string;
    output?: string;
    preset?: string;
    priority?: number;
    error_message?: string;
    retry_count?: number;
    max_retries?: number;
  }) {
    const result = this.db
      .prepare(
        `INSERT INTO tasks (type, status, progress, dataset, input, output, preset, priority, retry_count, max_retries, error_message)
                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      )
      .run(
        task.type,
        task.status || 'pending',
        task.progress || 0,
        task.dataset || null,
        task.input || null,
        task.output || null,
        task.preset || null,
        task.priority || 0,
        task.retry_count || 0,
        task.max_retries || null,
        task.error_message || null,
      );
    return { id: result.lastInsertRowid, ...task };
  }

  deleteTask(id: number) {
    return this.db.prepare('DELETE FROM tasks WHERE id = ?').run(id);
  }

  updateTask(
    id: number,
    updates: {
      status?: string;
      progress?: number;
      dataset?: string;
      input?: string;
      output?: string;
      preset?: string;
      priority?: number;
      error_message?: string;
      retry_count?: number;
      max_retries?: number;
    },
  ) {
    const setParts = [];
    const values = [];

    if (updates.status !== undefined) {
      setParts.push('status = ?');
      values.push(updates.status);
    }

    if (updates.progress !== undefined) {
      setParts.push('progress = ?');
      values.push(updates.progress);
    }

    if (updates.dataset !== undefined) {
      setParts.push('dataset = ?');
      values.push(updates.dataset);
    }

    if (updates.input !== undefined) {
      setParts.push('input = ?');
      values.push(updates.input);
    }

    if (updates.output !== undefined) {
      setParts.push('output = ?');
      values.push(updates.output);
    }

    if (updates.preset !== undefined) {
      setParts.push('preset = ?');
      values.push(updates.preset);
    }

    if (updates.priority !== undefined) {
      setParts.push('priority = ?');
      values.push(updates.priority);
    }

    if (updates.error_message !== undefined) {
      setParts.push('error_message = ?');
      values.push(updates.error_message);
    }

    if (updates.retry_count !== undefined) {
      setParts.push('retry_count = ?');
      values.push(updates.retry_count);
    }

    if (updates.max_retries !== undefined) {
      setParts.push('max_retries = ?');
      values.push(updates.max_retries);
    }

    if (setParts.length > 0) {
      setParts.push('updated_at = CURRENT_TIMESTAMP');
      values.push(id);

      this.db
        .prepare(`UPDATE tasks SET ${setParts.join(', ')} WHERE id = ?`)
        .run(...values);
    }

    return this.db.prepare('SELECT * FROM tasks WHERE id = ?').get(id);
  }

  // Task maintenance methods
  deleteTasksByStatus(status: string, olderThanDays?: number) {
    let query = 'DELETE FROM tasks WHERE status = ?';
    const params = [status];

    if (olderThanDays !== undefined) {
      query += ` AND created_at < datetime('now', '-${olderThanDays} days')`;
    }

    return this.db.prepare(query).run(...params);
  }

  deleteTasksOlderThan(days: number) {
    return this.db
      .prepare(
        `DELETE FROM tasks WHERE created_at < datetime('now', '-${days} days')`,
      )
      .run();
  }

  getTaskStats() {
    const stats = this.db
      .prepare(
        `
        SELECT
          status,
          COUNT(*) as count,
          MIN(created_at) as oldest,
          MAX(created_at) as newest
        FROM tasks
        GROUP BY status
      `,
      )
      .all();

    const total = this.db
      .prepare('SELECT COUNT(*) as total FROM tasks')
      .get() as { total: number };

    return {
      total: total.total,
      byStatus: stats,
    };
  }

  archiveOldTasks(daysOld: number = 30): { changes?: number } {
    // Create archive table if it doesn't exist
    this.db.exec(`
      CREATE TABLE IF NOT EXISTS tasks_archive (
        id INTEGER PRIMARY KEY,
        type TEXT NOT NULL,
        status TEXT NOT NULL,
        progress REAL DEFAULT 0,
        dataset TEXT,
        input TEXT,
        output TEXT,
        preset TEXT,
        priority INTEGER DEFAULT 0,
        retry_count INTEGER DEFAULT 0,
        max_retries INTEGER,
        error_message TEXT,
        created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
        updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
        archived_at DATETIME DEFAULT CURRENT_TIMESTAMP
      )
    `);

    // Move old completed/failed tasks to archive
    const insertResult = this.db
      .prepare(
        `
      INSERT INTO tasks_archive
      SELECT *, CURRENT_TIMESTAMP as archived_at
      FROM tasks
      WHERE status IN ('completed', 'failed', 'skipped')
      AND created_at < datetime('now', '-${daysOld} days')
    `,
      )
      .run();

    // Delete archived tasks from main table
    const deleteResult = this.db
      .prepare(
        `
      DELETE FROM tasks
      WHERE status IN ('completed', 'failed', 'skipped')
      AND created_at < datetime('now', '-${daysOld} days')
    `,
      )
      .run();

    return { changes: insertResult.changes };
  }

  // Purge all tasks from the database
  purgeAllTasks() {
    const result = this.db.prepare('DELETE FROM tasks').run();
    return result;
  }

  // ============================================================
  // Hash-based duplicate detection methods
  // ============================================================

  /**
   * Store a destination file with its hash and size
   */
  storeDestinationFile(
    dataset: string,
    destinationPath: string,
    hash: string,
    fileSize: number,
  ) {
    // Use destination_path as both input and destination_path for consistency with indexing worker
    // This prevents duplicates by using the (dataset, input) primary key
    const existing = this.db
      .prepare('SELECT * FROM files WHERE dataset = ? AND input = ?')
      .get(dataset, destinationPath) as
      | {
          dataset: string;
          input: string | null;
          output: string | null;
          destination_path: string;
          hash: string | null;
          file_size: number | null;
        }
      | undefined;

    const now = new Date().toISOString();

    if (existing) {
      this.db
        .prepare(
          `UPDATE files
           SET destination_path = ?, hash = ?, file_size = ?, date = ?
           WHERE dataset = ? AND input = ?`,
        )
        .run(destinationPath, hash, fileSize, now, dataset, destinationPath);
    } else {
      // Use destination_path as input for the primary key
      this.db
        .prepare(
          `INSERT INTO files (dataset, input, destination_path, hash, file_size, date, status)
           VALUES (?, ?, ?, ?, ?, ?, 'indexed')`,
        )
        .run(dataset, destinationPath, destinationPath, hash, fileSize, now);
    }
  }

  /**
   * Find duplicate files by hash and size
   */
  findDuplicatesByHash(
    hash: string,
    fileSize: number,
    dataset?: string,
  ): Array<{
    dataset: string;
    input: string | null;
    output: string | null;
    destination_path: string | null;
    hash: string;
    file_size: number;
    date: string;
    status: string;
  }> {
    let query = 'SELECT * FROM files WHERE hash = ? AND file_size = ?';
    const params: any[] = [hash, fileSize];

    if (dataset) {
      query += ' AND dataset = ?';
      params.push(dataset);
    }

    return this.db.prepare(query).all(...params) as Array<{
      dataset: string;
      input: string | null;
      output: string | null;
      destination_path: string | null;
      hash: string;
      file_size: number;
      date: string;
      status: string;
    }>;
  }

  /**
   * Get all duplicates from the view
   */
  getAllDuplicates(dataset?: string) {
    let query = 'SELECT * FROM file_duplicates';
    const params: any[] = [];

    if (dataset) {
      query += ' WHERE dataset = ?';
      params.push(dataset);
    }

    return this.db.prepare(query).all(...params) as Array<{
      hash: string;
      file_size: number;
      dataset: string;
      file_count: number;
      file_paths: string;
    }>;
  }

  /**
   * Get files in a destination that need hash indexing
   */
  getDestinationFilesWithoutHash(dataset: string, destinationPath?: string) {
    let query = `
      SELECT * FROM files 
      WHERE dataset = ? 
        AND destination_path IS NOT NULL 
        AND hash IS NULL
    `;
    const params: any[] = [dataset];

    if (destinationPath) {
      query += ' AND destination_path LIKE ?';
      params.push(`${destinationPath}%`);
    }

    return this.db.prepare(query).all(...params);
  }

  /**
   * Remove all destination file entries (for re-indexing)
   */
  clearDestinationFiles(dataset: string, destinationPath?: string) {
    let query =
      'DELETE FROM files WHERE dataset = ? AND destination_path IS NOT NULL';
    const params: any[] = [dataset];

    if (destinationPath) {
      query += ' AND destination_path LIKE ?';
      params.push(`${destinationPath}%`);
    }

    const result = this.db.prepare(query).run(...params);
    return result.changes;
  }

  /**
   * Get count of indexed destination files
   */
  getDestinationFileCount(dataset: string, destinationPath?: string) {
    let query =
      'SELECT COUNT(*) as count FROM files WHERE dataset = ? AND destination_path IS NOT NULL';
    const params: any[] = [dataset];

    if (destinationPath) {
      query += ' AND destination_path LIKE ?';
      params.push(`${destinationPath}%`);
    }

    const result = this.db.prepare(query).get(...params) as { count: number };
    return result.count;
  }

  /**
   * Update hash and file_size for a file after processing
   * Used by handbrake service after encoding completes
   */
  updateFileHash(
    dataset: string,
    filePath: string,
    hash: string,
    fileSize: number,
  ) {
    const now = new Date().toISOString();
    const stmt = this.db.prepare(`
      UPDATE files
      SET hash = ?, file_size = ?, date = ?
      WHERE dataset = ? AND input = ?
    `);
    return stmt.run(hash, fileSize, now, dataset, filePath);
  }

  /**
   * Remove duplicate file entries
   * Removes:
   * 1. Legacy duplicates where input = NULL and a matching entry with input = destination_path exists
   * 2. Multiple entries with the same output path (keeps the most recent)
   * 3. Multiple entries with the same destination_path (keeps the most recent)
   */
  removeDuplicateFileEntries() {
    let totalRemoved = 0;

    // 1. Remove legacy duplicates (input IS NULL)
    const deleteLegacyStmt = this.db.prepare(`
      DELETE FROM files
      WHERE input IS NULL
      AND destination_path IS NOT NULL
      AND EXISTS (
        SELECT 1 FROM files f2
        WHERE f2.dataset = files.dataset
        AND f2.input = files.destination_path
        AND f2.destination_path = files.destination_path
      )
    `);
    const legacyResult = deleteLegacyStmt.run();
    totalRemoved += legacyResult.changes;

    // 2. Remove duplicate entries with same output path (keep most recent)
    const deleteOutputDupsStmt = this.db.prepare(`
      DELETE FROM files
      WHERE rowid NOT IN (
        SELECT MAX(rowid)
        FROM files
        WHERE output IS NOT NULL
        GROUP BY dataset, output
      )
      AND output IS NOT NULL
    `);
    const outputDupsResult = deleteOutputDupsStmt.run();
    totalRemoved += outputDupsResult.changes;

    // 3. Remove duplicate entries with same destination_path (keep most recent)
    const deleteDestDupsStmt = this.db.prepare(`
      DELETE FROM files
      WHERE rowid NOT IN (
        SELECT MAX(rowid)
        FROM files
        WHERE destination_path IS NOT NULL
        GROUP BY dataset, destination_path
      )
      AND destination_path IS NOT NULL
    `);
    const destDupsResult = deleteDestDupsStmt.run();
    totalRemoved += destDupsResult.changes;

    return totalRemoved;
  }
}