package config

import (
	"fmt"
	"os"
	"strconv"
)

type Config struct {
	// Server
	Port    string
	BaseURL string

	// R2
	R2AccountID       string
	R2AccessKeyID     string
	R2SecretAccessKey  string
	R2BucketName      string
	R2Endpoint        string

	// Limits
	MaxUploadSize     int64 // bytes
	DefaultExpiryDays int   // 0 = no default expiry

	// Rate limiting
	RateLimit   float64 // requests per second per IP
	RateBurst   int

	// Database
	DBPath string
}

func Load() (*Config, error) {
	c := &Config{
		Port:    getEnv("PORT", "8080"),
		BaseURL: getEnv("BASE_URL", "http://localhost:8080"),

		R2AccountID:      os.Getenv("R2_ACCOUNT_ID"),
		R2AccessKeyID:    os.Getenv("R2_ACCESS_KEY_ID"),
		R2SecretAccessKey: os.Getenv("R2_SECRET_ACCESS_KEY"),
		R2BucketName:     getEnv("R2_BUCKET_NAME", "uploads"),

		DBPath: getEnv("DB_PATH", "/data/upload.db"),
	}

	c.R2Endpoint = fmt.Sprintf("https://%s.r2.cloudflarestorage.com", c.R2AccountID)

	maxSize, err := strconv.ParseInt(getEnv("MAX_UPLOAD_SIZE", "5368709120"), 10, 64) // 5GB default
	if err != nil {
		return nil, fmt.Errorf("invalid MAX_UPLOAD_SIZE: %w", err)
	}
	c.MaxUploadSize = maxSize

	c.DefaultExpiryDays, _ = strconv.Atoi(getEnv("DEFAULT_EXPIRY_DAYS", "0"))

	rateLimit, _ := strconv.ParseFloat(getEnv("RATE_LIMIT", "2"), 64)
	c.RateLimit = rateLimit
	c.RateBurst, _ = strconv.Atoi(getEnv("RATE_BURST", "5"))

	if c.R2AccountID == "" || c.R2AccessKeyID == "" || c.R2SecretAccessKey == "" {
		return nil, fmt.Errorf("R2_ACCOUNT_ID, R2_ACCESS_KEY_ID, and R2_SECRET_ACCESS_KEY are required")
	}

	return c, nil
}

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