import { Injectable, OnModuleInit } from '@nestjs/common';
import Database from 'better-sqlite3';
import * as fs from 'fs';
import { config, dbPath } from '../config';

export interface RunRow {
  id: string;
  original_filename: string;
  status: 'pending' | 'running' | 'done' | 'error';
  created_at: string;
  finished_at: string | null;
  params_json: string | null;
  report_json: string | null;
  log: string;
  error: string | null;
}

@Injectable()
export class DatabaseService implements OnModuleInit {
  private db!: Database.Database;

  onModuleInit() {
    fs.mkdirSync(config.dataDir, { recursive: true });
    this.db = new Database(dbPath());
    this.db.pragma('journal_mode = WAL');
    this.db.exec(`
      CREATE TABLE IF NOT EXISTS runs (
        id TEXT PRIMARY KEY,
        original_filename TEXT NOT NULL,
        status TEXT NOT NULL,
        created_at TEXT NOT NULL,
        finished_at TEXT,
        params_json TEXT,
        report_json TEXT,
        log TEXT NOT NULL DEFAULT '',
        error TEXT
      );
    `);
  }

  insert(row: Pick<RunRow, 'id' | 'original_filename' | 'status' | 'created_at' | 'params_json'>) {
    this.db
      .prepare(
        `INSERT INTO runs (id, original_filename, status, created_at, params_json, log) VALUES (?, ?, ?, ?, ?, '')`,
      )
      .run(row.id, row.original_filename, row.status, row.created_at, row.params_json);
  }

  updateStatus(id: string, status: RunRow['status']) {
    this.db.prepare(`UPDATE runs SET status = ? WHERE id = ?`).run(status, id);
  }

  appendLog(id: string, line: string) {
    this.db.prepare(`UPDATE runs SET log = log || ? WHERE id = ?`).run(`[${new Date().toISOString()}] ${line}\n`, id);
  }

  complete(id: string, reportJson: string) {
    this.db
      .prepare(`UPDATE runs SET status = 'done', report_json = ?, finished_at = ? WHERE id = ?`)
      .run(reportJson, new Date().toISOString(), id);
  }

  fail(id: string, error: string) {
    this.db.prepare(`UPDATE runs SET status = 'error', error = ?, finished_at = ? WHERE id = ?`).run(error, new Date().toISOString(), id);
  }

  get(id: string): RunRow | undefined {
    return this.db.prepare(`SELECT * FROM runs WHERE id = ?`).get(id) as RunRow | undefined;
  }

  list(): RunRow[] {
    return this.db.prepare(`SELECT * FROM runs ORDER BY created_at DESC`).all() as RunRow[];
  }

  remove(id: string) {
    this.db.prepare(`DELETE FROM runs WHERE id = ?`).run(id);
  }
}