package database

import (
	"context"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

// DB holds the database connection pool
type DB struct {
	Pool *pgxpool.Pool
}

// Config holds database configuration
type Config struct {
	Host     string
	Port     string
	User     string
	Password string
	DBName   string
	SSLMode  string
}

// NewConfig creates a new database config from environment variables
func NewConfig() *Config {
	return &Config{
		Host:     getEnv("DB_HOST", "localhost"),
		Port:     getEnv("DB_PORT", "5432"),
		User:     getEnv("DB_USER", "postgres"),
		Password: getEnv("DB_PASSWORD", "postgres"),
		DBName:   getEnv("DB_NAME", "breakpilot"),
		SSLMode:  getEnv("DB_SSLMODE", "disable"),
	}
}

func getEnv(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}

// ConnectionString returns the PostgreSQL connection string
func (c *Config) ConnectionString() string {
	return fmt.Sprintf(
		"postgres://%s:%s@%s:%s/%s?sslmode=%s",
		c.User, c.Password, c.Host, c.Port, c.DBName, c.SSLMode,
	)
}

// New creates a new database connection
func New(ctx context.Context, cfg *Config) (*DB, error) {
	config, err := pgxpool.ParseConfig(cfg.ConnectionString())
	if err != nil {
		return nil, fmt.Errorf("failed to parse database config: %w", err)
	}

	// Configure connection pool
	config.MaxConns = 10
	config.MinConns = 2
	config.MaxConnLifetime = time.Hour
	config.MaxConnIdleTime = 30 * time.Minute

	pool, err := pgxpool.NewWithConfig(ctx, config)
	if err != nil {
		return nil, fmt.Errorf("failed to create connection pool: %w", err)
	}

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

	log.Printf("Connected to database %s on %s:%s", cfg.DBName, cfg.Host, cfg.Port)

	return &DB{Pool: pool}, nil
}

// Close closes the database connection pool
func (db *DB) Close() {
	if db.Pool != nil {
		db.Pool.Close()
	}
}

// RunMigrations executes all SQL migrations
func (db *DB) RunMigrations(ctx context.Context) error {
	// Try multiple paths for migration file
	migrationPaths := []string{
		"migrations/001_university_staff.sql",
		"../migrations/001_university_staff.sql",
		"../../migrations/001_university_staff.sql",
	}

	var content []byte
	var err error
	var foundPath string

	for _, path := range migrationPaths {
		absPath, _ := filepath.Abs(path)
		content, err = os.ReadFile(absPath)
		if err == nil {
			foundPath = absPath
			break
		}
	}

	if content == nil {
		return fmt.Errorf("failed to read migration file from any path: %w", err)
	}

	log.Printf("Running migrations from: %s", foundPath)

	// Execute migration
	_, err = db.Pool.Exec(ctx, string(content))
	if err != nil {
		return fmt.Errorf("failed to execute migration: %w", err)
	}

	log.Println("Database migrations completed successfully")
	return nil
}

// Health checks if the database is healthy
func (db *DB) Health(ctx context.Context) error {
	return db.Pool.Ping(ctx)
}