init

internal/billing/lemon.go

@@ -0,0 +1,234 @@
+package billing
+
+import (
+	"bytes"
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+)
+
+const lemonBaseURL = "https://api.lemonsqueezy.com/v1"
+
+type LemonClient struct {
+	apiKey        string
+	storeID       string
+	webhookSecret string
+	httpClient    *http.Client
+}
+
+func NewLemonClient() *LemonClient {
+	return &LemonClient{
+		apiKey:        os.Getenv("LEMON_API_KEY"),
+		storeID:       os.Getenv("LEMON_STORE_ID"),
+		webhookSecret: os.Getenv("LEMON_WEBHOOK_SECRET"),
+		httpClient:    &http.Client{},
+	}
+}
+
+func (c *LemonClient) IsConfigured() bool {
+	return c.apiKey != "" && c.storeID != ""
+}
+
+type CheckoutRequest struct {
+	StoreID         string            `json:"store_id"`
+	VariantID       string            `json:"variant_id"`
+	CustomPrice     *int              `json:"custom_price,omitempty"`
+	CheckoutOptions *CheckoutOptions  `json:"checkout_options,omitempty"`
+	CheckoutData    *CheckoutData     `json:"checkout_data,omitempty"`
+}
+
+type CheckoutOptions struct {
+	Embed bool `json:"embed,omitempty"`
+}
+
+type CheckoutData struct {
+	Email  string            `json:"email,omitempty"`
+	Name   string            `json:"name,omitempty"`
+	Custom map[string]string `json:"custom,omitempty"`
+}
+
+type CheckoutResponse struct {
+	Data struct {
+		ID         string `json:"id"`
+		Attributes struct {
+			URL string `json:"url"`
+		} `json:"attributes"`
+	} `json:"data"`
+}
+
+func (c *LemonClient) CreateCheckout(ctx context.Context, req *CheckoutRequest) (*CheckoutResponse, error) {
+	if req.StoreID == "" {
+		req.StoreID = c.storeID
+	}
+
+	payload := map[string]any{
+		"data": map[string]any{
+			"type":       "checkouts",
+			"attributes": req,
+			"relationships": map[string]any{
+				"store": map[string]any{
+					"data": map[string]any{"type": "stores", "id": req.StoreID},
+				},
+				"variant": map[string]any{
+					"data": map[string]any{"type": "variants", "id": req.VariantID},
+				},
+			},
+		},
+	}
+
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return nil, err
+	}
+
+	httpReq, err := http.NewRequestWithContext(ctx, "POST", lemonBaseURL+"/checkouts", bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+
+	httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
+	httpReq.Header.Set("Content-Type", "application/vnd.api+json")
+	httpReq.Header.Set("Accept", "application/vnd.api+json")
+
+	resp, err := c.httpClient.Do(httpReq)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("checkout creation failed (status %d): %s", resp.StatusCode, string(respBody))
+	}
+
+	var checkoutResp CheckoutResponse
+	if err := json.Unmarshal(respBody, &checkoutResp); err != nil {
+		return nil, err
+	}
+
+	return &checkoutResp, nil
+}
+
+func (c *LemonClient) CreateSubscriptionCheckout(ctx context.Context, variantID, email, name string, custom map[string]string) (string, error) {
+	req := &CheckoutRequest{
+		VariantID: variantID,
+		CheckoutData: &CheckoutData{
+			Email:  email,
+			Name:   name,
+			Custom: custom,
+		},
+		CheckoutOptions: &CheckoutOptions{Embed: true},
+	}
+
+	resp, err := c.CreateCheckout(ctx, req)
+	if err != nil {
+		return "", err
+	}
+
+	return resp.Data.Attributes.URL, nil
+}
+
+func (c *LemonClient) CreateDonationCheckout(ctx context.Context, variantID string, amountCents int, email, name, message string, custom map[string]string) (string, error) {
+	if custom == nil {
+		custom = make(map[string]string)
+	}
+	if message != "" {
+		custom["message"] = message
+	}
+
+	req := &CheckoutRequest{
+		VariantID:   variantID,
+		CustomPrice: &amountCents,
+		CheckoutData: &CheckoutData{
+			Email:  email,
+			Name:   name,
+			Custom: custom,
+		},
+		CheckoutOptions: &CheckoutOptions{Embed: true},
+	}
+
+	resp, err := c.CreateCheckout(ctx, req)
+	if err != nil {
+		return "", err
+	}
+
+	return resp.Data.Attributes.URL, nil
+}
+
+func (c *LemonClient) VerifyWebhook(payload []byte, signature string) bool {
+	if c.webhookSecret == "" {
+		return false
+	}
+
+	mac := hmac.New(sha256.New, []byte(c.webhookSecret))
+	mac.Write(payload)
+	expectedSig := hex.EncodeToString(mac.Sum(nil))
+
+	return hmac.Equal([]byte(signature), []byte(expectedSig))
+}
+
+type WebhookEvent struct {
+	Meta struct {
+		EventName  string            `json:"event_name"`
+		CustomData map[string]string `json:"custom_data"`
+	} `json:"meta"`
+	Data json.RawMessage `json:"data"`
+}
+
+type SubscriptionData struct {
+	ID         string `json:"id"`
+	Attributes struct {
+		CustomerID  int    `json:"customer_id"`
+		VariantName string `json:"variant_name"`
+		UserName    string `json:"user_name"`
+		UserEmail   string `json:"user_email"`
+		Status      string `json:"status"`
+		RenewsAt    string `json:"renews_at"`
+		FirstSubscriptionItem struct {
+			Price int `json:"price"`
+		} `json:"first_subscription_item"`
+	} `json:"attributes"`
+}
+
+type OrderData struct {
+	ID         string `json:"id"`
+	Attributes struct {
+		UserName  string `json:"user_name"`
+		UserEmail string `json:"user_email"`
+		TotalUsd  int    `json:"total_usd"`
+	} `json:"attributes"`
+}
+
+func (c *LemonClient) ParseWebhookEvent(payload []byte) (*WebhookEvent, error) {
+	var event WebhookEvent
+	if err := json.Unmarshal(payload, &event); err != nil {
+		return nil, err
+	}
+	return &event, nil
+}
+
+func (e *WebhookEvent) GetSubscriptionData() (*SubscriptionData, error) {
+	var data SubscriptionData
+	if err := json.Unmarshal(e.Data, &data); err != nil {
+		return nil, err
+	}
+	return &data, nil
+}
+
+func (e *WebhookEvent) GetOrderData() (*OrderData, error) {
+	var data OrderData
+	if err := json.Unmarshal(e.Data, &data); err != nil {
+		return nil, err
+	}
+	return &data, nil
+}