package payment

import (
	"fmt"
	"net/url"
	"os"
	"strings"
)

// WaffoConfig hosted checkout settings for pancake.waffo.ai // Logan.Li
type WaffoConfig struct {
	CheckoutURL         string
	StoreSlug           string
	ProductID           string
	ProductIDYearly     string
	ProductIDPerpetual  string
	Currency            string // fallback / default
	CurrencyYearly      string
	CurrencyPerpetual   string
	Environment         string
	SuccessURL          string
}

// LoadWaffoConfig reads WAFFO_* env vars (same names as OpsXShell legacy license-server). // Logan.Li
func LoadWaffoConfig() WaffoConfig {
	env := strings.TrimSpace(os.Getenv("WAFFO_ENVIRONMENT"))
	if env == "" {
		env = "test"
	}
	success := strings.TrimSpace(os.Getenv("SUCCESS_URL"))
	if success == "" {
		success = "opsxshell://pro/activated"
	}
	currency := strings.TrimSpace(os.Getenv("WAFFO_CURRENCY"))
	if currency == "" {
		currency = "CNY"
	}
	currencyYearly := strings.TrimSpace(os.Getenv("WAFFO_CURRENCY_YEARLY"))
	if currencyYearly == "" {
		currencyYearly = currency
	}
	currencyPerpetual := strings.TrimSpace(os.Getenv("WAFFO_CURRENCY_PERPETUAL"))
	if currencyPerpetual == "" {
		// 永久默认 USD（与 pancake 商品一致）；可用环境变量覆盖。 // Logan.Li
		if currency == "CNY" {
			currencyPerpetual = "USD"
		} else {
			currencyPerpetual = currency
		}
	}
	defaultProduct := strings.TrimSpace(os.Getenv("WAFFO_PRODUCT_ID"))
	yearly := strings.TrimSpace(os.Getenv("WAFFO_PRODUCT_ID_YEARLY"))
	perpetual := strings.TrimSpace(os.Getenv("WAFFO_PRODUCT_ID_PERPETUAL"))
	if yearly == "" {
		yearly = defaultProduct
	}
	if perpetual == "" {
		perpetual = defaultProduct
	}
	return WaffoConfig{
		CheckoutURL:        strings.TrimSpace(os.Getenv("WAFFO_CHECKOUT_URL")),
		StoreSlug:          strings.TrimSpace(os.Getenv("WAFFO_STORE_SLUG")),
		ProductID:          defaultProduct,
		ProductIDYearly:    yearly,
		ProductIDPerpetual: perpetual,
		Currency:           currency,
		CurrencyYearly:     currencyYearly,
		CurrencyPerpetual:  currencyPerpetual,
		Environment:        env,
		SuccessURL:         success,
	}
}

// BuildCheckoutURL returns a Waffo hosted checkout URL with order/device/email metadata. // Logan.Li
func BuildCheckoutURL(cfg WaffoConfig, orderNo, deviceID, email, returnURL, planType string) (string, error) {
	success := cfg.SuccessURL
	if strings.TrimSpace(returnURL) != "" {
		success = strings.TrimSpace(returnURL)
	}
	u, err := resolveBaseCheckoutURL(cfg, planType)
	if err != nil {
		return "", err
	}
	q := u.Query()
	if q.Get("successUrl") == "" {
		q.Set("successUrl", appendQuery(success, map[string]string{
			"orderNo":  orderNo,
			"deviceId": deviceID,
			"email":    email,
			"planType": planType,
		}))
	}
	if deviceID != "" {
		q.Set("deviceId", deviceID)
	}
	if orderNo != "" {
		q.Set("orderNo", orderNo)
	}
	if email != "" {
		q.Set("email", email)
	}
	if planType != "" {
		q.Set("planType", planType)
	}
	u.RawQuery = q.Encode()
	return u.String(), nil
}

func productIDForPlan(cfg WaffoConfig, planType string) string {
	switch strings.TrimSpace(planType) {
	case "yearly", "monthly":
		return cfg.ProductIDYearly
	case "perpetual", "lifetime":
		return cfg.ProductIDPerpetual
	default:
		if cfg.ProductIDPerpetual != "" {
			return cfg.ProductIDPerpetual
		}
		return cfg.ProductID
	}
}

func currencyForPlan(cfg WaffoConfig, planType string) string {
	switch strings.TrimSpace(planType) {
	case "yearly", "monthly":
		if cfg.CurrencyYearly != "" {
			return cfg.CurrencyYearly
		}
	case "perpetual", "lifetime":
		if cfg.CurrencyPerpetual != "" {
			return cfg.CurrencyPerpetual
		}
	}
	if cfg.Currency != "" {
		return cfg.Currency
	}
	return "CNY"
}

func checkoutTypeForPlan(planType string) string {
	// OpsXShell 包年 / 永久均为 Waffo onetime 商品（包年不再走 subscription）。 // Logan.Li
	_ = planType
	return "onetime"
}

func resolveBaseCheckoutURL(cfg WaffoConfig, planType string) (*url.URL, error) {
	// Prefer store + per-plan product IDs so yearly/perpetual map to different Waffo SKUs.
	productID := productIDForPlan(cfg, planType)
	if cfg.StoreSlug != "" && productID != "" {
		raw := fmt.Sprintf("https://pancake.waffo.ai/store/%s/product/%s", cfg.StoreSlug, productID)
		u, err := url.Parse(raw)
		if err != nil {
			return nil, err
		}
		q := u.Query()
		q.Set("type", checkoutTypeForPlan(planType))
		q.Set("currency", currencyForPlan(cfg, planType))
		if cfg.Environment == "test" {
			q.Set("test", "true")
		}
		u.RawQuery = q.Encode()
		return u, nil
	}
	if cfg.CheckoutURL != "" {
		return url.Parse(cfg.CheckoutURL)
	}
	return nil, fmt.Errorf("未配置 WAFFO_STORE_SLUG 与 WAFFO_PRODUCT_ID_YEARLY / WAFFO_PRODUCT_ID_PERPETUAL（或 WAFFO_CHECKOUT_URL）")
}

func appendQuery(raw string, values map[string]string) string {
	u, err := url.Parse(raw)
	if err != nil {
		return raw
	}
	q := u.Query()
	for k, v := range values {
		if v != "" {
			q.Set(k, v)
		}
	}
	u.RawQuery = q.Encode()
	return u.String()
}