import { spawn } from "child_process";
import http from "http";
import https from "https";
import { URL } from "url";
import path from "path";
import fs from "fs";
import { prisma } from "@repo/db/client";

const MIGRATIONS_DIR = path.resolve(__dirname, "../../../../packages/db/prisma/migrations");

async function applyMissingMigrations() {
  let folders: string[];
  try {
    folders = fs.readdirSync(MIGRATIONS_DIR)
      .filter((name) => fs.statSync(path.join(MIGRATIONS_DIR, name)).isDirectory())
      .sort();
  } catch {
    console.warn("Could not read migrations directory, skipping post-sync migration.");
    return;
  }

  let applied: Set<string>;
  try {
    const rows = await prisma.$queryRaw<{ migration_name: string }[]>`
      SELECT migration_name FROM "_prisma_migrations" WHERE finished_at IS NOT NULL
    `;
    applied = new Set(rows.map((r: { migration_name: string }) => r.migration_name));
  } catch {
    applied = new Set();
  }

  for (const folder of folders) {
    if (applied.has(folder)) continue;
    const sqlFile = path.join(MIGRATIONS_DIR, folder, "migration.sql");
    if (!fs.existsSync(sqlFile)) continue;
    const sql = fs.readFileSync(sqlFile, "utf8");
    try {
      await prisma.$executeRawUnsafe(sql);
      console.log(`Applied migration: ${folder}`);
    } catch (err: any) {
      console.warn(`Migration ${folder} had errors (may already be applied):`, err.message);
    }
  }
}

export function runNetworkSync(sourceUrl: string, apiKey: string): Promise<void> {
  return new Promise((resolve, reject) => {
    let targetUrl: URL;
    try {
      targetUrl = new URL("/api/database-management/network-backup", sourceUrl);
    } catch {
      return reject(new Error(`Invalid source URL: ${sourceUrl}`));
    }

    const client = targetUrl.protocol === "https:" ? https : http;

    const req = client.get(
      targetUrl.href,
      { headers: { "x-network-backup-key": apiKey } },
      async (res) => {
        if (res.statusCode !== 200) {
          res.resume();
          return reject(
            new Error(`Source returned HTTP ${res.statusCode}: ${res.statusMessage}`)
          );
        }

        // Drop and recreate the public schema
        try {
          await prisma.$executeRawUnsafe(`DROP SCHEMA public CASCADE`);
          await prisma.$executeRawUnsafe(`CREATE SCHEMA public`);
        } catch (err: any) {
          res.destroy();
          return reject(new Error(`Failed to reset schema: ${err.message}`));
        }

        const psql = spawn(
          "psql",
          [
            "-h", process.env.DB_HOST || "localhost",
            "-U", process.env.DB_USER || "postgres",
            process.env.DB_NAME || "dental_db",
          ],
          { env: { ...process.env, PGPASSWORD: process.env.DB_PASSWORD } }
        );

        let stderr = "";
        psql.stderr.on("data", (d) => (stderr += d.toString()));
        psql.on("error", (err) => reject(new Error(`Failed to start psql: ${err.message}`)));

        psql.on("close", async (code) => {
          if (code !== 0) {
            return reject(new Error(`psql exited ${code}: ${stderr}`));
          }
          try {
            await prisma.$disconnect();
            await prisma.$connect();
          } catch (_) {}
          try {
            await applyMissingMigrations();
          } catch (err) {
            console.error("applyMissingMigrations failed after network sync:", err);
          }
          resolve();
        });

        res.pipe(psql.stdin);
      }
    );

    req.on("error", (err) => reject(new Error(`Network request failed: ${err.message}`)));
    req.setTimeout(120_000, () => {
      req.destroy();
      reject(new Error("Network backup request timed out after 120s"));
    });
  });
}