/**
 * Data Routes
 *
 * Handles data retrieval operations: observations, summaries, prompts, stats, processing status.
 * All endpoints use direct database access via domain services.
 */

import express, { Request, Response } from 'express';
import path from 'path';
import { readFileSync, statSync, existsSync } from 'fs';
import { homedir } from 'os';
import { getPackageRoot } from '../../../../shared/paths.js';
import { getWorkerPort } from '../../../../shared/worker-utils.js';
import { PaginationHelper } from '../../PaginationHelper.js';
import { DatabaseManager } from '../../DatabaseManager.js';
import { SessionManager } from '../../SessionManager.js';
import { SSEBroadcaster } from '../../SSEBroadcaster.js';
import type { WorkerService } from '../../../worker-service.js';
import { BaseRouteHandler } from '../BaseRouteHandler.js';

export class DataRoutes extends BaseRouteHandler {
  constructor(
    private paginationHelper: PaginationHelper,
    private dbManager: DatabaseManager,
    private sessionManager: SessionManager,
    private sseBroadcaster: SSEBroadcaster,
    private workerService: WorkerService,
    private startTime: number
  ) {
    super();
  }

  setupRoutes(app: express.Application): void {
    // Pagination endpoints
    app.get('/api/observations', this.handleGetObservations.bind(this));
    app.get('/api/summaries', this.handleGetSummaries.bind(this));
    app.get('/api/prompts', this.handleGetPrompts.bind(this));

    // Fetch by ID endpoints
    app.get('/api/observation/:id', this.handleGetObservationById.bind(this));
    app.post('/api/observations/batch', this.handleGetObservationsByIds.bind(this));
    app.get('/api/session/:id', this.handleGetSessionById.bind(this));
    app.get('/api/prompt/:id', this.handleGetPromptById.bind(this));

    // Metadata endpoints
    app.get('/api/stats', this.handleGetStats.bind(this));
    app.get('/api/projects', this.handleGetProjects.bind(this));

    // Processing status endpoints
    app.get('/api/processing-status', this.handleGetProcessingStatus.bind(this));
    app.post('/api/processing', this.handleSetProcessing.bind(this));
  }

  /**
   * Get paginated observations
   */
  private handleGetObservations = this.wrapHandler((req: Request, res: Response): void => {
    const { offset, limit, project } = this.parsePaginationParams(req);
    const result = this.paginationHelper.getObservations(offset, limit, project);
    res.json(result);
  });

  /**
   * Get paginated summaries
   */
  private handleGetSummaries = this.wrapHandler((req: Request, res: Response): void => {
    const { offset, limit, project } = this.parsePaginationParams(req);
    const result = this.paginationHelper.getSummaries(offset, limit, project);
    res.json(result);
  });

  /**
   * Get paginated user prompts
   */
  private handleGetPrompts = this.wrapHandler((req: Request, res: Response): void => {
    const { offset, limit, project } = this.parsePaginationParams(req);
    const result = this.paginationHelper.getPrompts(offset, limit, project);
    res.json(result);
  });

  /**
   * Get observation by ID
   * GET /api/observation/:id
   */
  private handleGetObservationById = this.wrapHandler((req: Request, res: Response): void => {
    const id = this.parseIntParam(req, res, 'id');
    if (id === null) return;

    const store = this.dbManager.getSessionStore();
    const observation = store.getObservationById(id);

    if (!observation) {
      this.notFound(res, `Observation #${id} not found`);
      return;
    }

    res.json(observation);
  });

  /**
   * Get observations by array of IDs
   * POST /api/observations/batch
   * Body: { ids: number[], orderBy?: 'date_desc' | 'date_asc', limit?: number, project?: string }
   */
  private handleGetObservationsByIds = this.wrapHandler((req: Request, res: Response): void => {
    const { ids, orderBy, limit, project } = req.body;

    if (!ids || !Array.isArray(ids)) {
      this.badRequest(res, 'ids must be an array of numbers');
      return;
    }

    if (ids.length === 0) {
      res.json([]);
      return;
    }

    // Validate all IDs are numbers
    if (!ids.every(id => typeof id === 'number' && Number.isInteger(id))) {
      this.badRequest(res, 'All ids must be integers');
      return;
    }

    const store = this.dbManager.getSessionStore();
    const observations = store.getObservationsByIds(ids, { orderBy, limit, project });

    res.json(observations);
  });

  /**
   * Get session by ID
   * GET /api/session/:id
   */
  private handleGetSessionById = this.wrapHandler((req: Request, res: Response): void => {
    const id = this.parseIntParam(req, res, 'id');
    if (id === null) return;

    const store = this.dbManager.getSessionStore();
    const sessions = store.getSessionSummariesByIds([id]);

    if (sessions.length === 0) {
      this.notFound(res, `Session #${id} not found`);
      return;
    }

    res.json(sessions[0]);
  });

  /**
   * Get user prompt by ID
   * GET /api/prompt/:id
   */
  private handleGetPromptById = this.wrapHandler((req: Request, res: Response): void => {
    const id = this.parseIntParam(req, res, 'id');
    if (id === null) return;

    const store = this.dbManager.getSessionStore();
    const prompts = store.getUserPromptsByIds([id]);

    if (prompts.length === 0) {
      this.notFound(res, `Prompt #${id} not found`);
      return;
    }

    res.json(prompts[0]);
  });

  /**
   * Get database statistics (with worker metadata)
   */
  private handleGetStats = this.wrapHandler((req: Request, res: Response): void => {
    const db = this.dbManager.getSessionStore().db;

    // Read version from package.json
    const packageRoot = getPackageRoot();
    const packageJsonPath = path.join(packageRoot, 'package.json');
    const packageJson = JSON.parse(readFileSync(packageJsonPath, 'utf-8'));
    const version = packageJson.version;

    // Get database stats
    const totalObservations = db.prepare('SELECT COUNT(*) as count FROM observations').get() as { count: number };
    const totalSessions = db.prepare('SELECT COUNT(*) as count FROM sdk_sessions').get() as { count: number };
    const totalSummaries = db.prepare('SELECT COUNT(*) as count FROM session_summaries').get() as { count: number };

    // Get database file size and path
    const dbPath = path.join(homedir(), '.claude-mem', 'claude-mem.db');
    let dbSize = 0;
    if (existsSync(dbPath)) {
      dbSize = statSync(dbPath).size;
    }

    // Worker metadata
    const uptime = Math.floor((Date.now() - this.startTime) / 1000);
    const activeSessions = this.sessionManager.getActiveSessionCount();
    const sseClients = this.sseBroadcaster.getClientCount();

    res.json({
      worker: {
        version,
        uptime,
        activeSessions,
        sseClients,
        port: getWorkerPort()
      },
      database: {
        path: dbPath,
        size: dbSize,
        observations: totalObservations.count,
        sessions: totalSessions.count,
        summaries: totalSummaries.count
      }
    });
  });

  /**
   * Get list of distinct projects from observations
   * GET /api/projects
   */
  private handleGetProjects = this.wrapHandler((req: Request, res: Response): void => {
    const db = this.dbManager.getSessionStore().db;

    const rows = db.prepare(`
      SELECT DISTINCT project
      FROM observations
      WHERE project IS NOT NULL
      GROUP BY project
      ORDER BY MAX(created_at_epoch) DESC
    `).all() as Array<{ project: string }>;

    const projects = rows.map(row => row.project);

    res.json({ projects });
  });

  /**
   * Get current processing status
   * GET /api/processing-status
   */
  private handleGetProcessingStatus = this.wrapHandler((req: Request, res: Response): void => {
    const isProcessing = this.sessionManager.isAnySessionProcessing();
    const queueDepth = this.sessionManager.getTotalActiveWork(); // Includes queued + actively processing
    res.json({ isProcessing, queueDepth });
  });

  /**
   * Set processing status (called by hooks)
   * NOTE: This now broadcasts computed status based on active processing (ignores input)
   */
  private handleSetProcessing = this.wrapHandler((req: Request, res: Response): void => {
    // Broadcast current computed status (ignores manual input)
    this.workerService.broadcastProcessingStatus();

    const isProcessing = this.sessionManager.isAnySessionProcessing();
    const queueDepth = this.sessionManager.getTotalQueueDepth();
    const activeSessions = this.sessionManager.getActiveSessionCount();

    res.json({ status: 'ok', isProcessing });
  });

  /**
   * Parse pagination parameters from request query
   */
  private parsePaginationParams(req: Request): { offset: number; limit: number; project?: string } {
    const offset = parseInt(req.query.offset as string, 10) || 0;
    const limit = Math.min(parseInt(req.query.limit as string, 10) || 20, 100); // Max 100
    const project = req.query.project as string | undefined;

    return { offset, limit, project };
  }
}
