import "dotenv/config";
import { existsSync, readFileSync, readdirSync } from "node:fs";
import { join } from "node:path";

import { loadConfig } from "../src/config.js";
import { createLogger } from "../src/logger.js";
import { MySqlSessionStore } from "../src/sessions/mysql_store.js";
import type { SessionMessage, SessionMeta } from "../src/sessions/store.js";

interface SessionIndexFile {
  sessions?: Record<string, SessionMeta>;
}

const config = loadConfig();
const logger = createLogger(config.logLevel);
const dryRun = process.argv.includes("--dry-run");

async function main(): Promise<void> {
  const store = new MySqlSessionStore(config.mysql, logger);
  await store.init();

  let sessionCount = 0;
  let messageCount = 0;
  let skipped = 0;

  if (existsSync(config.sessionsFile)) {
    const parsed = JSON.parse(readFileSync(config.sessionsFile, "utf8")) as SessionIndexFile;
    const sessions = Object.values(parsed.sessions ?? {});
    for (const meta of sessions) {
      if (!meta.session_id) {
        skipped += 1;
        continue;
      }
      if (!dryRun) await store.upsertSession(meta);
      sessionCount += 1;
    }
  }

  if (existsSync(config.messagesDir)) {
    for (const file of readdirSync(config.messagesDir)) {
      if (!file.endsWith(".jsonl")) continue;
      const sessionId = file.slice(0, -".jsonl".length);
      const lines = readFileSync(join(config.messagesDir, file), "utf8").split("\n");
      for (const line of lines) {
        const trimmed = line.trim();
        if (!trimmed) continue;
        let message: SessionMessage;
        try {
          message = JSON.parse(trimmed) as SessionMessage;
        } catch {
          skipped += 1;
          continue;
        }
        if (!message.id || !message.session_id) {
          message.id = message.id || `${sessionId}-${messageCount}`;
          message.session_id = message.session_id || sessionId;
        }
        if (!dryRun) await store.insertMessage(message);
        messageCount += 1;
      }
    }
  }

  console.log(
    `${dryRun ? "[dry-run] " : ""}migrated sessions=${sessionCount} messages=${messageCount} skipped=${skipped}`,
  );
  await store.close();
}

main().catch((error) => {
  console.error("migration failed:", error);
  process.exit(1);
});