package sms

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"

	openapi "github.com/alibabacloud-go/darabonba-openapi/v2/client"
	dysmsapi20170525 "github.com/alibabacloud-go/dysmsapi-20170525/v3/client"
	tea "github.com/alibabacloud-go/tea/tea"
)

// Config holds Aliyun SMS configuration.
type Config struct {
	AccessKeyID     string
	AccessKeySecret string
	SignName        string
	TemplateCode    string
	Endpoint        string // default: dysmsapi.aliyuncs.com
}

type Client struct {
	cfg    Config
	client *dysmsapi20170525.Client
}

// New creates an Aliyun SMS client. Does not send any request.
func New(cfg Config) (*Client, error) {
	if strings.TrimSpace(cfg.AccessKeyID) == "" || strings.TrimSpace(cfg.AccessKeySecret) == "" {
		return nil, errors.New("sms: access key not configured")
	}
	if strings.TrimSpace(cfg.SignName) == "" || strings.TrimSpace(cfg.TemplateCode) == "" {
		return nil, errors.New("sms: signName/templateCode not configured")
	}
	if strings.TrimSpace(cfg.Endpoint) == "" {
		cfg.Endpoint = "dysmsapi.aliyuncs.com"
	}

	oc := &openapi.Config{
		AccessKeyId:     tea.String(cfg.AccessKeyID),
		AccessKeySecret: tea.String(cfg.AccessKeySecret),
		Endpoint:        tea.String(cfg.Endpoint),
	}
	cli, err := dysmsapi20170525.NewClient(oc)
	if err != nil {
		return nil, err
	}
	return &Client{cfg: cfg, client: cli}, nil
}

// TemplateData matches the Java version: time/name/content
type TemplateData struct {
	Time    string `json:"time"`
	Name    string `json:"name"`
	Content string `json:"content"`
	Alert   string `json:"alert"`
}

// Send sends the template message to one or more phone numbers.
// name/content/alert/msgTime map to template ${name}, ${content}, ${alert}, ${time}.
func (c *Client) Send(ctx context.Context, name, content, alert, msgTime string, phones []string) error {
	if len(phones) == 0 {
		return errors.New("sms: empty phone list")
	}
	payload := TemplateData{Time: msgTime, Name: name, Content: content, Alert: alert}
	b, _ := json.Marshal(payload)
	param := string(b)

	// Aliyun supports multiple comma-separated numbers, but keep batches small if needed.
	joined := strings.Join(phones, ",")
	req := &dysmsapi20170525.SendSmsRequest{
		PhoneNumbers:  tea.String(joined),
		SignName:      tea.String(c.cfg.SignName),
		TemplateCode:  tea.String(c.cfg.TemplateCode),
		TemplateParam: tea.String(param),
	}

	// Execute request
	resp, err := c.client.SendSms(req)
	if err != nil {
		return err
	}
	code := tea.StringValue(resp.Body.Code)
	if strings.ToUpper(code) != "OK" {
		return fmt.Errorf("sms: send failed code=%s message=%s requestId=%s", code, tea.StringValue(resp.Body.Message), tea.StringValue(resp.Body.RequestId))
	}
	return nil
}