package email

import (
	"bytes"
	"encoding/json"
	"errors"
	"net/http"
	"time"

	"github.com/spf13/viper"
)

type Client struct {
	apiKey string
	http   *http.Client
}

// Resend service client
func NewResendClient() (*Client, error) {
	key := viper.GetString("email.resend_api_key")
	if key == "" {
		return nil, errors.New("RESEND_API_KEY not set")
	}

	return &Client{
		apiKey: key,
		http: &http.Client{
			Timeout: 10 * time.Second,
		},
	}, nil
}

type sendEmailRequest struct {
	From    string   `json:"from"`
	To      []string `json:"to"`
	Subject string   `json:"subject"`
	HTML    string   `json:"html,omitempty"`
	Text    string   `json:"text,omitempty"`
}

type sendEmailResponse struct {
	ID string `json:"id"`
}

// Send email by resend API
func (c *Client) Send(to, subject, html string) (string, error) {
	reqBody := sendEmailRequest{
		From:    viper.GetString("email.from"),
		To:      []string{to},
		Subject: subject,
		HTML:    html,
	}

	body, err := json.Marshal(reqBody)
	if err != nil {
		return "", err
	}

	req, err := http.NewRequest(
		http.MethodPost,
		"https://api.resend.com/emails",
		bytes.NewReader(body),
	)
	if err != nil {
		return "", err
	}

	req.Header.Set("Authorization", "Bearer "+c.apiKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := c.http.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 300 {
		return "", errors.New("resend send failed")
	}

	var res sendEmailResponse
	if err := json.NewDecoder(resp.Body).Decode(&res); err != nil {
		return "", err
	}

	return res.ID, nil
}