import { createHash } from "node:crypto";
import fs from "node:fs";
import net from "node:net";
import os from "node:os";
import path from "node:path";
import { afterEach, describe, expect, it } from "vitest";
import postgres from "postgres";
import {
  applyPendingMigrations,
  ensurePostgresDatabase,
  inspectMigrations,
} from "./client.js";

type EmbeddedPostgresInstance = {
  initialise(): Promise<void>;
  start(): Promise<void>;
  stop(): Promise<void>;
};

type EmbeddedPostgresCtor = new (opts: {
  databaseDir: string;
  user: string;
  password: string;
  port: number;
  persistent: boolean;
  initdbFlags?: string[];
  onLog?: (message: unknown) => void;
  onError?: (message: unknown) => void;
}) => EmbeddedPostgresInstance;

const tempPaths: string[] = [];
const runningInstances: EmbeddedPostgresInstance[] = [];

async function getEmbeddedPostgresCtor(): Promise<EmbeddedPostgresCtor> {
  const mod = await import("embedded-postgres");
  return mod.default as EmbeddedPostgresCtor;
}

async function getAvailablePort(): Promise<number> {
  return await new Promise((resolve, reject) => {
    const server = net.createServer();
    server.unref();
    server.on("error", reject);
    server.listen(0, "127.0.0.1", () => {
      const address = server.address();
      if (!address || typeof address === "string") {
        server.close(() => reject(new Error("Failed to allocate test port")));
        return;
      }
      const { port } = address;
      server.close((error) => {
        if (error) reject(error);
        else resolve(port);
      });
    });
  });
}

async function createTempDatabase(): Promise<string> {
  const dataDir = fs.mkdtempSync(path.join(os.tmpdir(), "paperclip-db-client-"));
  tempPaths.push(dataDir);
  const port = await getAvailablePort();
  const EmbeddedPostgres = await getEmbeddedPostgresCtor();
  const instance = new EmbeddedPostgres({
    databaseDir: dataDir,
    user: "paperclip",
    password: "paperclip",
    port,
    persistent: true,
    initdbFlags: ["--encoding=UTF8", "--locale=C"],
    onLog: () => {},
    onError: () => {},
  });
  await instance.initialise();
  await instance.start();
  runningInstances.push(instance);

  const adminUrl = `postgres://paperclip:paperclip@127.0.0.1:${port}/postgres`;
  await ensurePostgresDatabase(adminUrl, "paperclip");
  return `postgres://paperclip:paperclip@127.0.0.1:${port}/paperclip`;
}

async function migrationHash(migrationFile: string): Promise<string> {
  const content = await fs.promises.readFile(
    new URL(`./migrations/${migrationFile}`, import.meta.url),
    "utf8",
  );
  return createHash("sha256").update(content).digest("hex");
}

afterEach(async () => {
  while (runningInstances.length > 0) {
    const instance = runningInstances.pop();
    if (!instance) continue;
    await instance.stop();
  }
  while (tempPaths.length > 0) {
    const tempPath = tempPaths.pop();
    if (!tempPath) continue;
    fs.rmSync(tempPath, { recursive: true, force: true });
  }
});

describe("applyPendingMigrations", () => {
  it(
    "applies an inserted earlier migration without replaying later legacy migrations",
    async () => {
      const connectionString = await createTempDatabase();

      await applyPendingMigrations(connectionString);

      const sql = postgres(connectionString, { max: 1, onnotice: () => {} });
      try {
        const richMagnetoHash = await migrationHash("0030_rich_magneto.sql");

        await sql.unsafe(
          `DELETE FROM "drizzle"."__drizzle_migrations" WHERE hash = '${richMagnetoHash}'`,
        );
        await sql.unsafe(`DROP TABLE "company_logos"`);
      } finally {
        await sql.end();
      }

      const pendingState = await inspectMigrations(connectionString);
      expect(pendingState).toMatchObject({
        status: "needsMigrations",
        pendingMigrations: ["0030_rich_magneto.sql"],
        reason: "pending-migrations",
      });

      await applyPendingMigrations(connectionString);

      const finalState = await inspectMigrations(connectionString);
      expect(finalState.status).toBe("upToDate");

      const verifySql = postgres(connectionString, { max: 1, onnotice: () => {} });
      try {
        const rows = await verifySql.unsafe<{ table_name: string }[]>(
          `
            SELECT table_name
            FROM information_schema.tables
            WHERE table_schema = 'public'
              AND table_name IN ('company_logos', 'execution_workspaces')
            ORDER BY table_name
          `,
        );
        expect(rows.map((row) => row.table_name)).toEqual([
          "company_logos",
          "execution_workspaces",
        ]);
      } finally {
        await verifySql.end();
      }
    },
    20_000,
  );
});