package config

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"
	"os"
	"path/filepath"

	"github.com/joho/godotenv"
)

type Config struct {
	Port          string
	GinMode       string
	DataDir       string
	SessionSecret string
	MySQLHost     string
	MySQLPort     string
	MySQLUser     string
	MySQLPassword string
	MySQLDatabase string
}

func Load() *Config {
	// Load .env file if present (ignore error if missing)
	godotenv.Load()

	cfg := &Config{
		Port:          getEnv("PORT", "8080"),
		GinMode:       getEnv("GIN_MODE", "debug"),
		DataDir:       getEnv("DATA_DIR", "data"),
		SessionSecret: getEnv("SESSION_SECRET", ""),
		MySQLHost:     getEnv("MYSQL_HOST", "127.0.0.1"),
		MySQLPort:     getEnv("MYSQL_PORT", "3306"),
		MySQLUser:     getEnv("MYSQL_USER", "root"),
		MySQLPassword: getEnv("MYSQL_PASSWORD", ""),
		MySQLDatabase: getEnv("MYSQL_DATABASE", "pr_helper"),
	}
	// Generate random session secret if not provided
	if cfg.SessionSecret == "" {
		b := make([]byte, 32)
		rand.Read(b)
		cfg.SessionSecret = hex.EncodeToString(b)
	}
	// Ensure data directories exist
	os.MkdirAll(cfg.DataDir, 0o755)
	os.MkdirAll(filepath.Join(cfg.DataDir, "repos"), 0o755)
	return cfg
}

// MySQLDSN returns the MySQL Data Source Name for go-sql-driver/mysql.
func (c *Config) MySQLDSN() string {
	return fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local",
		c.MySQLUser, c.MySQLPassword, c.MySQLHost, c.MySQLPort, c.MySQLDatabase)
}

func (c *Config) ReposDir() string {
	return filepath.Join(c.DataDir, "repos")
}

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