package config

import (
	"os"
	"path/filepath"
	"strings"
)

// Config holds runtime settings for the RCS backend.
type Config struct {
	Addr          string
	DataDir       string
	DBPath        string
	ScreenshotDir string
	APIKey        string
	ImgurClientID string
	// PublicBaseURL is the canonical public origin (e.g. https://rcs.example.com).
	PublicBaseURL string
	// TrustProxy honors X-Forwarded-Proto / X-Forwarded-Host when behind a reverse proxy.
	TrustProxy bool
}

// Load reads configuration from environment variables with sensible defaults.
func Load() Config {
	dataDir := envOr("RCS_DATA_DIR", "data")
	dbPath := envOr("RCS_DB_PATH", filepath.Join(dataDir, "rcs.db"))
	screenshotDir := filepath.Join(dataDir, "screenshots")

	return Config{
		Addr:          envOr("RCS_ADDR", "127.0.0.1:8080"),
		DataDir:       dataDir,
		DBPath:        dbPath,
		ScreenshotDir: screenshotDir,
		APIKey:        os.Getenv("RCS_API_KEY"),
		ImgurClientID: os.Getenv("IMGUR_CLIENT_ID"),
		PublicBaseURL: strings.TrimRight(os.Getenv("RCS_PUBLIC_BASE_URL"), "/"),
		TrustProxy:    envTruthy("RCS_TRUST_PROXY"),
	}
}

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

func envTruthy(key string) bool {
	switch strings.ToLower(strings.TrimSpace(os.Getenv(key))) {
	case "1", "true", "yes", "on":
		return true
	default:
		return false
	}
}