package main

import (
	"database/sql"
	"fmt"
	"log"
	"os"

	_ "github.com/lib/pq"
)

var db *sql.DB

// InitDB initializes the database connection (legacy function)
func InitDB() error {
	// Get database URL from environment variable
	dbURL := os.Getenv("DATABASE_URL")
	if dbURL == "" {
		// Default for local development
		dbURL = "postgres://postgres:password@localhost:5432/counter_db?sslmode=disable"
	}
	return initDBWithURL(dbURL)
}

// InitDBWithConfig initializes the database connection with configuration
func InitDBWithConfig(config *Config) error {
	return initDBWithURL(config.DatabaseURL)
}

// initDBWithURL initializes the database connection with a specific URL
func initDBWithURL(dbURL string) error {

	var err error
	db, err = sql.Open("postgres", dbURL)
	if err != nil {
		return fmt.Errorf("failed to open database: %w", err)
	}

	// Test the connection
	if err = db.Ping(); err != nil {
		return fmt.Errorf("failed to ping database: %w", err)
	}

	log.Println("✅ Database connection established successfully")
	return nil
}

// CreateTables creates the necessary database tables
func CreateTables() error {
	queries := []string{
		`CREATE TABLE IF NOT EXISTS users (
			id SERIAL PRIMARY KEY,
			username VARCHAR(50) UNIQUE NOT NULL,
			email VARCHAR(255) UNIQUE NOT NULL,
			password VARCHAR(255) NOT NULL,
			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
		)`,
		`CREATE TABLE IF NOT EXISTS counters (
			id SERIAL PRIMARY KEY,
			user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
			name VARCHAR(100) NOT NULL,
			description TEXT,
			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
			updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
		)`,
		`CREATE TABLE IF NOT EXISTS counter_entries (
			id SERIAL PRIMARY KEY,
			counter_id INTEGER REFERENCES counters(id) ON DELETE CASCADE,
			value INTEGER NOT NULL,
			date DATE NOT NULL,
			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
		)`,
		`CREATE INDEX IF NOT EXISTS idx_counters_user_id ON counters(user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_counter_entries_counter_id ON counter_entries(counter_id)`,
		`CREATE INDEX IF NOT EXISTS idx_counter_entries_date ON counter_entries(date)`,
	}

	for _, query := range queries {
		if _, err := db.Exec(query); err != nil {
			return fmt.Errorf("failed to execute query: %w", err)
		}
	}

	log.Println("✅ Database tables created successfully")
	return nil
}

// GetDB returns the database connection
func GetDB() *sql.DB {
	return db
}