// Set isolated DB path before import to protect production data
process.env.DB_PATH = "./data/test-isolated.sqlite";

import { test, expect, beforeEach, afterEach, afterAll } from "bun:test";
import { Database } from "bun:sqlite";
import { unlinkSync, existsSync, mkdirSync } from "node:fs";
import { initializeDatabase } from "../../src/db/db";

// Type-safe helpers for database query results
interface DbTable {
  name: string;
}

interface DbVersion {
  user_version?: number;
}

interface DbJournalMode {
  journal_mode?: string;
}

interface DbColumnInfo {
  name: string;
  type?: string;
}

interface DbUser {
  id?: number;
  email?: string;
}

interface DbCount {
  count: number;
}

interface DbTest {
  test: number;
}

function queryAllTables(database: Database): DbTable[] {
  return database
    .query("SELECT name FROM sqlite_master WHERE type='table' ORDER BY name")
    .all() as DbTable[];
}

function getDbVersion(database: Database): number | undefined {
  const result = database.query("PRAGMA user_version").get() as DbVersion;
  return result.user_version;
}

function getJournalMode(database: Database): string | undefined {
  const result = database.query("PRAGMA journal_mode").get() as DbJournalMode;
  return result.journal_mode;
}

function getColumnInfo(database: Database, table: string): DbColumnInfo[] {
  return database.query(`PRAGMA table_info(${table})`).all() as DbColumnInfo[];
}

// Test database initialization and migration paths
let testDbPath: string;
let testDb: Database;

beforeEach(() => {
  mkdirSync("./data", { recursive: true });
  testDbPath = `./data/test-db-${Date.now()}.sqlite`;
  testDb = new Database(testDbPath, { create: true });
  // Now uses the real initialization logic from db.ts
  initializeDatabase(testDb);
});

afterEach(() => {
  if (testDb) {
    testDb.close();
  }
  if (existsSync(testDbPath)) {
    unlinkSync(testDbPath);
  }
  if (existsSync(`${testDbPath}-wal`)) {
    try {
      unlinkSync(`${testDbPath}-wal`);
    } catch (err) {
      // WAL file cleanup error - log but don't fail test
      if (err instanceof Error && err.message.includes("ENOENT")) {
        // File already gone, which is fine
      }
    }
  }
  if (existsSync(`${testDbPath}-shm`)) {
    try {
      unlinkSync(`${testDbPath}-shm`);
    } catch (err) {
      // SHM file cleanup error - log but don't fail test
      if (err instanceof Error && err.message.includes("ENOENT")) {
        // File already gone, which is fine
      }
    }
  }
});

afterAll(() => {
  // Cleanup of the isolated test database after the test run
  if (existsSync("./data/test-isolated.sqlite")) {
    unlinkSync("./data/test-isolated.sqlite");
  }
  if (existsSync("./data/test-isolated.sqlite-wal")) {
    try {
      unlinkSync("./data/test-isolated.sqlite-wal");
    } catch (err) {
      // WAL file cleanup error - log but don't fail test
      if (err instanceof Error && err.message.includes("ENOENT")) {
        // File already gone, which is fine
      }
    }
  }
  if (existsSync("./data/test-isolated.sqlite-shm")) {
    try {
      unlinkSync("./data/test-isolated.sqlite-shm");
    } catch (err) {
      // SHM file cleanup error - log but don't fail test
      if (err instanceof Error && err.message.includes("ENOENT")) {
        // File already gone, which is fine
      }
    }
  }
});

test("db initializes and creates tables on first run", () => {
  const tables = queryAllTables(testDb);
  expect(tables.length).toBeGreaterThanOrEqual(3);
  expect(tables.map((t) => t.name)).toContain("users");
  expect(tables.map((t) => t.name)).toContain("jobs");
  expect(tables.map((t) => t.name)).toContain("file_names");
  expect(getDbVersion(testDb)).toBe(1);
});

test("db handles migration from version 0 to version 1", () => {
  testDb.close();
  const migrateDbPath = `./data/test-db-migrate-${Date.now()}.sqlite`;
  const migrateDb = new Database(migrateDbPath, { create: true });

  // Simulates a real v0 database state
  migrateDb.exec(`
    CREATE TABLE IF NOT EXISTS users (
                                       id INTEGER PRIMARY KEY AUTOINCREMENT,
                                       email TEXT NOT NULL,
                                       password TEXT NOT NULL
    );
    CREATE TABLE IF NOT EXISTS file_names (
                                            id INTEGER PRIMARY KEY AUTOINCREMENT,
                                            job_id INTEGER NOT NULL,
                                            file_name TEXT NOT NULL,
                                            output_file_name TEXT NOT NULL,
                                            FOREIGN KEY (job_id) REFERENCES jobs(id)
      );
    CREATE TABLE IF NOT EXISTS jobs (
                                      id INTEGER PRIMARY KEY AUTOINCREMENT,
                                      user_id INTEGER NOT NULL,
                                      date_created TEXT NOT NULL,
                                      FOREIGN KEY (user_id) REFERENCES users(id)
      );
    PRAGMA user_version = 0;
  `);

  // Now runs the real migration logic from db.ts
  initializeDatabase(migrateDb);

  expect(getDbVersion(migrateDb)).toBe(1);
  const columnInfo = getColumnInfo(migrateDb, "file_names");
  expect(columnInfo.map((c) => c.name)).toContain("status");

  migrateDb.close();
  if (existsSync(migrateDbPath)) unlinkSync(migrateDbPath);
  if (existsSync(`${migrateDbPath}-wal`)) unlinkSync(`${migrateDbPath}-wal`);
  if (existsSync(`${migrateDbPath}-shm`)) unlinkSync(`${migrateDbPath}-shm`);
});

test("db enables WAL mode", () => {
  expect(getJournalMode(testDb)?.toLowerCase()).toBe("wal");
});

test("db module exports a working database instance", () => {
  expect(testDb).toBeTruthy();
  const tables = queryAllTables(testDb);
  expect(tables.length).toBeGreaterThanOrEqual(3);
  const tableNames = tables.map((t) => t.name);
  expect(tableNames).toContain("users");
  expect(tableNames).toContain("jobs");
  expect(tableNames).toContain("file_names");
});

test("db has correct schema with status column", () => {
  // Verify file_names table has the status column (created during initialization)
  const columns = getColumnInfo(testDb, "file_names");
  const columnNames = columns.map((c) => c.name);
  expect(columnNames).toContain("status");
  expect(columnNames).toContain("job_id");
  expect(columnNames).toContain("file_name");
  expect(columnNames).toContain("output_file_name");
});

test("db version is set to 1", () => {
  // Verify that PRAGMA user_version is set (as per db.ts initialization)
  expect(getDbVersion(testDb)).toBe(1);
});

test("db has WAL mode enabled", () => {
  // Verify that WAL mode is enabled (as per db.ts last step)
  expect(getJournalMode(testDb)?.toLowerCase()).toBe("wal");
});

test("db can insert and query data", () => {
  // Test that the database is functional
  // Insert a test user
  const stmt = testDb.prepare("INSERT INTO users (email, password) VALUES (?, ?)");
  const result = stmt.run("test@example.com", "hashedpassword");
  // Verify that the insert happened (run() returns result object)
  expect(result).toBeTruthy();

  // Query the inserted user
  const user = testDb
    .query("SELECT * FROM users WHERE email = ?")
    .get("test@example.com") as DbUser;
  expect(user).toBeTruthy();
  expect(user.email).toBe("test@example.com");

  // Cleanup
  testDb.query("DELETE FROM users WHERE email = ?").run("test@example.com");
});

test("db initialization creates all three tables if missing", () => {
  // Get the current tables to verify the initialization worked
  const tables = queryAllTables(testDb);

  // The initialization in db.ts creates these three tables
  const expectedTables = ["file_names", "jobs", "users"];
  const actualTableNames = tables.map((t) => t.name).sort();

  // Verify all expected tables exist (this validates the initialization path)
  for (const expectedTable of expectedTables) {
    expect(actualTableNames).toContain(expectedTable);
  }

  // Verify the initial version pragma was set during initialization
  expect(getDbVersion(testDb)).toBe(1);
});

test("db.ts migration logic correctly handles version upgrades", () => {
  // The migration path in db.ts checks for version 0 and upgrades to version 1
  // We verify this by checking that:
  // 1. Current version is 1 (set during init or migration)
  expect(getDbVersion(testDb)).toBe(1);

  // 2. The status column exists (added by migration if version was 0)
  const columns = getColumnInfo(testDb, "file_names");
  const statusColumn = columns.find((c) => c.name === "status");
  expect(statusColumn).toBeTruthy();
  expect(statusColumn?.type).toBe("TEXT");
});

test("db.ts correctly sets WAL mode for performance", () => {
  // The db.ts runs PRAGMA journal_mode = WAL; at the end
  // This is important for concurrent access and performance
  expect(getJournalMode(testDb)?.toUpperCase()).toBe("WAL");
});

test("db initialization handles the case where sqlite_master query returns false", () => {
  // This test validates the logic path: if (!db.query(...).get()) {...}
  // In a fresh database, there are no tables, so the query returns falsy
  // and the CREATE TABLE statements execute.
  // We verify this by checking that the expected tables were created:
  const tableQuery = testDb.query("SELECT COUNT(*) as count FROM sqlite_master WHERE type='table'");
  const result = tableQuery.get() as DbCount;

  // A freshly initialized db.ts should have created at least 3 tables
  expect(result.count).toBeGreaterThanOrEqual(3);
});

test("db.ts uses correct file path and creates in data directory", () => {
  // db.ts creates Database at "./data/mydb.sqlite"
  // We can't directly check the path, but we verify the DB is functional
  // and that operations work, which implies it's in the correct location

  // Try an operation that requires the DB to be properly initialized
  const result = testDb.query("SELECT 1 as test").get() as DbTest;
  expect(result.test).toBe(1);

  // Verify the DB directory structure is correct by checking table structure
  const tableInfo = getColumnInfo(testDb, "users");
  expect(tableInfo.length).toBeGreaterThan(0);
});