// Package common 提供各业务端共用的鉴权、资源、钱包和账户范围能力。
package common

import (
	"fmt"
	"regexp"
	"strings"
	"time"

	"git.apinb.com/bsm-sdk/core/crypto/token"
	"git.apinb.com/bsm-sdk/core/env"
	"git.apinb.com/bsm-sdk/core/errcode"
	"git.apinb.com/bsm-sdk/core/infra"
	sdkmiddleware "git.apinb.com/bsm-sdk/core/middleware"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/config"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/impl"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/models"
	"github.com/gin-gonic/gin"
	redis "github.com/redis/go-redis/v9"
)

var phonePattern = regexp.MustCompile(`^1[3-9]\d{9}$`)

var ErrVerificationUnavailable = errcode.NewError(2410, "短信验证服务尚未配置")

var verificationPurposes = map[string]struct{}{
	"login": {}, "register": {}, "reset_login_password": {}, "set_payment_password": {},
	"reset_payment_password": {}, "bind_bank": {}, "unbind_bank": {},
}

type verificationValue struct {
	Code    string `json:"code"`
	Phone   string `json:"phone"`
	Purpose string `json:"purpose"`
	Client  string `json:"client"`
}

// ValidPhone 判断手机号是否符合中国大陆手机号格式。
func ValidPhone(phone string) bool { return phonePattern.MatchString(strings.TrimSpace(phone)) }

// SendVerificationCode 创建一次性验证码。Mock 模式的验证码只保存在 Redis，不返回给客户端。
func SendVerificationCode(client string) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		var request struct {
			Phone   string `json:"phone" binding:"required"`
			Purpose string `json:"purpose" binding:"required"`
		}
		if ctx.ShouldBindJSON(&request) != nil || !ValidPhone(request.Phone) {
			infra.Response.Error(ctx, errcode.ErrInvalidArgument)
			return
		}
		if _, ok := verificationPurposes[request.Purpose]; !ok {
			infra.Response.Error(ctx, errcode.ErrInvalidArgument)
			return
		}
		if !config.Spec.Global.MockVerificationEnabled {
			infra.Response.Error(ctx, ErrVerificationUnavailable)
			return
		}
		if impl.RedisService == nil || impl.RedisService.Client == nil {
			infra.Response.Error(ctx, errcode.ErrRedis)
			return
		}
		phone := strings.TrimSpace(request.Phone)
		throttleKey := impl.RedisService.BuildKey("client-verification-throttle", client, phone)
		var sent bool
		if impl.RedisService.Get(throttleKey, &sent) == nil && sent {
			infra.Response.Error(ctx, errcode.ErrInvalidArgument)
			return
		}
		requestIdentity := models.NewIdentity()
		value := verificationValue{Code: config.Spec.Global.MockVerificationCode, Phone: phone, Purpose: request.Purpose, Client: client}
		ttl := time.Duration(config.Spec.Global.VerificationTTLSeconds) * time.Second
		if err := impl.RedisService.Set(verificationKey(requestIdentity), value, ttl); err != nil {
			infra.Response.Error(ctx, err)
			return
		}
		_ = impl.RedisService.Set(throttleKey, true, time.Duration(config.Spec.Global.VerificationSendIntervalSeconds)*time.Second)
		infra.Response.Success(ctx, gin.H{"request_identity": requestIdentity, "expires_in": config.Spec.Global.VerificationTTLSeconds,
			"delivery_mode": "mock", "delivery_status": "not_sent", "retry_after": config.Spec.Global.VerificationSendIntervalSeconds})
	}
}

// VerifyCode 校验并消费验证码。
func VerifyCode(client, phone, purpose, requestIdentity, code string) bool {
	if !config.Spec.Global.MockVerificationEnabled || requestIdentity == "" || code == "" || impl.RedisService == nil || impl.RedisService.Client == nil {
		return false
	}
	key := verificationKey(requestIdentity)
	result, err := consumeVerificationCode.Run(impl.RedisService.Ctx, impl.RedisService.Client,
		[]string{key}, client, strings.TrimSpace(phone), purpose, code).Int()
	return err == nil && result == 1
}

// 一次性验证码在Redis内完成校验和消费，两个并发请求只能有一个成功。
var consumeVerificationCode = redis.NewScript(`
local raw = redis.call('GET', KEYS[1])
if not raw then return 0 end
local ok, value = pcall(cjson.decode, raw)
if not ok or type(value) ~= 'table' then return 0 end
if value.client ~= ARGV[1] or value.phone ~= ARGV[2] or value.purpose ~= ARGV[3] or value.code ~= ARGV[4] then return 0 end
redis.call('DEL', KEYS[1])
return 1
`)

func verificationKey(identity string) string {
	return impl.RedisService.BuildKey("client-verification", identity)
}

// IssueToken 签发严格区分 user_app 和 service_app 的 JWT。
func IssueToken(identity, client, role string, extend map[string]string) (string, error) {
	return token.New(env.Runtime.JwtSecretKey).GenerateJwt(0, identity, client, role, nil, extend)
}

// RequireClient 验证客户端种类，阻止后台令牌跨端调用。
func RequireClient(client string) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		claims, err := sdkmiddleware.ParseAuth(ctx)
		if err != nil || claims.Client != client {
			infra.Response.Error(ctx, errcode.ErrPermissionDenied)
			ctx.Abort()
			return
		}
		ctx.Next()
	}
}

// UserAccount 返回当前启用的用户账户。
func UserAccount(ctx *gin.Context) (models.UserAccount, bool) {
	claims, err := sdkmiddleware.ParseAuth(ctx)
	if err != nil {
		infra.Response.Error(ctx, err)
		return models.UserAccount{}, false
	}
	var account models.UserAccount
	if impl.DBService.Where("identity = ? AND status = ?", claims.Identity, 1).First(&account).Error != nil {
		infra.Response.Error(ctx, errcode.ErrPermissionDenied)
		return models.UserAccount{}, false
	}
	return account, true
}

// StaffAccount 返回当前启用的工作人员账户。
func StaffAccount(ctx *gin.Context) (models.StaffAccount, bool) {
	claims, err := sdkmiddleware.ParseAuth(ctx)
	if err != nil {
		infra.Response.Error(ctx, err)
		return models.StaffAccount{}, false
	}
	var account models.StaffAccount
	if impl.DBService.Where("identity = ? AND status = ?", claims.Identity, 1).First(&account).Error != nil {
		infra.Response.Error(ctx, errcode.ErrPermissionDenied)
		return models.StaffAccount{}, false
	}
	return account, true
}

// RecordNo 生成便于检索的业务流水号。
func RecordNo(prefix string) string {
	return fmt.Sprintf("%s%d", prefix, time.Now().UnixNano())
}