package integration

import (
	"context"
	"regexp"
	"strings"

	"github.com/go-kratos/kratos/v3/errors"
)

var (
	ErrSMSInvalid  = errors.BadRequest("SMS_INVALID", "短信参数无效")
	ErrSMSDisabled = errors.BadRequest("SMS_DISABLED", "短信渠道未配置或未启用")
	ErrSMSFailed   = errors.BadRequest("SMS_SEND_FAILED", "短信提交失败，请检查服务商配置和账户状态")
)

// SMSMessage carries one recipient and provider-specific template parameters.
type SMSMessage struct {
	Provider    string
	Phone       string
	NamedParams map[string]string
	Params      []string
}

type SMSResult struct {
	RequestID string
	MessageID string
}

type SMSSender interface {
	Send(context.Context, *SMSMessage) (*SMSResult, error)
}

type SMSUsecase struct{ sender SMSSender }

func NewSMSUsecase(sender SMSSender) *SMSUsecase { return &SMSUsecase{sender: sender} }

var smsPhonePattern = regexp.MustCompile(`^\+[1-9][0-9]{6,14}$`)

func ValidateSMSMessage(m *SMSMessage) error {
	if m == nil || (m.Provider != "aliyun" && m.Provider != "tencent") || !smsPhonePattern.MatchString(m.Phone) {
		return ErrSMSInvalid
	}
	// The Aliyun adapter uses the mainland China SendSms API.
	if m.Provider == "aliyun" && (!strings.HasPrefix(m.Phone, "+861") || len(m.Phone) != 14 || len(m.Params) != 0) {
		return errors.BadRequest("SMS_INVALID", "阿里云短信请使用 +86 开头的中国大陆手机号及对象格式模板参数")
	}
	if m.Provider == "tencent" && len(m.NamedParams) != 0 {
		return errors.BadRequest("SMS_INVALID", "腾讯云短信模板参数必须是按模板顺序排列的字符串数组")
	}
	if len(m.NamedParams) > 20 || len(m.Params) > 20 {
		return ErrSMSInvalid
	}
	for key, value := range m.NamedParams {
		if strings.TrimSpace(key) == "" || len(key) > 64 || len(value) > 500 {
			return ErrSMSInvalid
		}
	}
	for _, value := range m.Params {
		if len(value) > 500 {
			return ErrSMSInvalid
		}
	}
	return nil
}

func (uc *SMSUsecase) Send(ctx context.Context, m *SMSMessage) (*SMSResult, error) {
	if err := ValidateSMSMessage(m); err != nil {
		return nil, err
	}
	return uc.sender.Send(ctx, m)
}

func validateSMSConfig(provider string, values map[string]any) error {
	definition, ok := IntegrationDefinition(IntegrationKindSMS, provider)
	if !ok {
		return errors.BadRequest("SMS_PROVIDER_INVALID", "不支持的短信服务商")
	}
	for _, field := range definition.Fields {
		value, ok := values[field.Key].(string)
		if !ok || len(value) > 512 || (field.Required && strings.TrimSpace(value) == "") {
			return errors.BadRequest("SMS_CONFIG_INVALID", "请填写有效的"+field.Label)
		}
	}
	return nil
}