/**
 * Database initialization script
 * Creates database and all required tables in PostgreSQL
 */

import postgres from "postgres";
import { readFileSync } from "fs";
import { join } from "path";

/**
 * Parse DATABASE_URL and extract components
 */
function parseDatabaseUrl(url: string): {
  protocol: string;
  user: string;
  password: string;
  host: string;
  port: string;
  database: string;
} {
  const match = url.match(
    /^postgresql:\/\/([^:]+):([^@]+)@([^:]+):(\d+)\/(.+)$/
  );
  if (!match) {
    throw new Error(
      "Invalid DATABASE_URL format. Expected: postgresql://user:password@host:port/database"
    );
  }
  return {
    protocol: "postgresql",
    user: match[1],
    password: match[2],
    host: match[3],
    port: match[4],
    database: match[5],
  };
}

async function initDatabase() {
  const dbUrl = process.env.DATABASE_URL;

  if (!dbUrl) {
    console.error("Error: DATABASE_URL environment variable is required");
    console.error("Please set it in your .env file or export it:");
    console.error(
      "  export DATABASE_URL=postgresql://user:password@host:port/database"
    );
    process.exit(1);
  }

  const dbConfig = parseDatabaseUrl(dbUrl);
  const targetDatabase = dbConfig.database;

  console.log(`Target database: ${targetDatabase}`);
  console.log(
    `Connecting to PostgreSQL server (${dbConfig.host}:${dbConfig.port})...`
  );

  // Connect to postgres database (default database) to create target database
  const adminUrl = `postgresql://${dbConfig.user}:${dbConfig.password}@${dbConfig.host}:${dbConfig.port}/postgres`;
  const adminSql = postgres(adminUrl);

  try {
    // Check if database exists
    const dbExists = await adminSql`
      SELECT 1 FROM pg_database WHERE datname = ${targetDatabase}
    `;

    if (dbExists.length === 0) {
      console.log(`Database "${targetDatabase}" does not exist. Creating...`);
      // Create database (escape database name to prevent SQL injection)
      // PostgreSQL identifiers are case-insensitive unless quoted, so we quote it
      const escapedDbName = `"${targetDatabase.replace(/"/g, '""')}"`;
      await (adminSql as any).unsafe(`CREATE DATABASE ${escapedDbName}`);
      console.log(`✓ Database "${targetDatabase}" created successfully`);
    } else {
      console.log(`✓ Database "${targetDatabase}" already exists`);
    }
  } catch (error) {
    const errorMessage = (error as Error).message;
    if (errorMessage.includes("already exists")) {
      console.log(`✓ Database "${targetDatabase}" already exists`);
    } else {
      console.error(`✗ Failed to create database: ${errorMessage}`);
      throw error;
    }
  } finally {
    await adminSql.end();
  }

  // Now connect to target database and create tables
  console.log(`\nConnecting to database "${targetDatabase}"...`);
  const sql = postgres(dbUrl);

  try {
    // Test connection
    await sql`SELECT 1`;
    console.log("✓ Connected to database");

    // Read schema file
    const schemaPath = join(process.cwd(), "src", "storage", "schema.sql");
    console.log(`Reading schema from ${schemaPath}...`);
    const schema = readFileSync(schemaPath, "utf-8");

    // Split by semicolons and execute each statement
    const statements = schema
      .split(";")
      .map((s) => s.trim())
      .filter((s) => s.length > 0 && !s.startsWith("--"));

    console.log(`Executing ${statements.length} SQL statements...`);

    for (const statement of statements) {
      if (statement) {
        try {
          // Use postgres.unsafe() to execute raw SQL
          await (sql as any).unsafe(statement);
          console.log(`✓ Executed: ${statement.substring(0, 50)}...`);
        } catch (error) {
          // Check if it's a "already exists" error (which is OK)
          const errorMessage = (error as Error).message;
          if (
            errorMessage.includes("already exists") ||
            errorMessage.includes("duplicate")
          ) {
            console.log(
              `⚠ Skipped (already exists): ${statement.substring(0, 50)}...`
            );
          } else {
            console.error(`✗ Error executing statement: ${errorMessage}`);
            console.error(`  Statement: ${statement.substring(0, 100)}...`);
            throw error;
          }
        }
      }
    }

    console.log("\n✓ Database initialization completed successfully!");
    console.log("\nTables created:");
    console.log("  - code_snippets");
    console.log("  - notes");
    console.log("  - tasks");
    console.log("  - baby_milestones");
    console.log("  - math_resources");
    console.log("  - game_wishlist");
  } catch (error) {
    console.error("\n✗ Database initialization failed:", error);
    process.exit(1);
  } finally {
    await sql.end();
  }
}

// Run initialization
initDatabase().catch((error) => {
  console.error("Fatal error:", error);
  process.exit(1);
});