package config

import (
	"fmt"
	"log/slog"
	"os"
	"strconv"
	"strings"
)

type Config struct {
	AppEnv            string
	LogLevel          slog.Level
	BackendAddr       string
	ConsoleProxyAddr  string
	WorkerConcurrency int
	DatabaseURL       string
	DatabaseDirectURL string
	SupabaseURL       string
	SupabaseJWKSURL   string
	SupabaseIssuer    string
	SupabaseJWTSecret string
	RedisAddr         string
	AppSiteURL        string
}

func Load() (Config, error) {
	logLevel, err := parseLogLevel(getenv("LOG_LEVEL", "info"))
	if err != nil {
		return Config{}, err
	}

	workerConcurrency, err := intFromEnv("WORKER_CONCURRENCY", 5)
	if err != nil {
		return Config{}, err
	}
	if workerConcurrency < 1 {
		return Config{}, fmt.Errorf("WORKER_CONCURRENCY must be greater than 0")
	}

	return Config{
		AppEnv:            getenv("APP_ENV", "development"),
		LogLevel:          logLevel,
		BackendAddr:       getenv("BACKEND_ADDR", ":8080"),
		ConsoleProxyAddr:  getenv("CONSOLE_PROXY_ADDR", ":8081"),
		WorkerConcurrency: workerConcurrency,
		DatabaseURL:       os.Getenv("DATABASE_URL"),
		DatabaseDirectURL: os.Getenv("DATABASE_DIRECT_URL"),
		SupabaseURL:       os.Getenv("SUPABASE_URL"),
		SupabaseJWKSURL:   os.Getenv("SUPABASE_JWKS_URL"),
		SupabaseIssuer:    os.Getenv("SUPABASE_ISSUER"),
		SupabaseJWTSecret: os.Getenv("SUPABASE_JWT_SECRET"),
		RedisAddr:         getenv("REDIS_ADDR", "localhost:6379"),
		AppSiteURL:        getenv("APP_SITE_URL", "http://localhost:5173"),
	}, nil
}

func getenv(key, fallback string) string {
	if value := strings.TrimSpace(os.Getenv(key)); value != "" {
		return value
	}
	return fallback
}

func intFromEnv(key string, fallback int) (int, error) {
	raw := strings.TrimSpace(os.Getenv(key))
	if raw == "" {
		return fallback, nil
	}

	value, err := strconv.Atoi(raw)
	if err != nil {
		return 0, fmt.Errorf("%s must be an integer: %w", key, err)
	}
	return value, nil
}

func parseLogLevel(raw string) (slog.Level, error) {
	switch strings.ToLower(strings.TrimSpace(raw)) {
	case "debug":
		return slog.LevelDebug, nil
	case "info":
		return slog.LevelInfo, nil
	case "warn", "warning":
		return slog.LevelWarn, nil
	case "error":
		return slog.LevelError, nil
	default:
		return slog.LevelInfo, fmt.Errorf("LOG_LEVEL must be one of debug, info, warn, error")
	}
}