package auth

import (
	"context"
	"errors"
	"fmt"

	"perms-system-server/internal/consts"
	"perms-system-server/internal/middleware"
	userModel "perms-system-server/internal/model/user"
	"perms-system-server/internal/response"
	"perms-system-server/internal/svc"
	"perms-system-server/internal/types"
	"perms-system-server/internal/util"

	"github.com/zeromicro/go-zero/core/limit"
	"github.com/zeromicro/go-zero/core/logx"
	"golang.org/x/crypto/bcrypt"
)

type ChangePasswordLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewChangePasswordLogic(ctx context.Context, svcCtx *svc.ServiceContext) *ChangePasswordLogic {
	return &ChangePasswordLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

// ChangePassword 修改密码。已登录用户验证原密码后设置新密码，同时递增 tokenVersion 使所有已签发令牌失效，强制重新登录。
func (l *ChangePasswordLogic) ChangePassword(req *types.ChangePasswordReq) error {
	if msg := util.ValidatePassword(req.NewPassword); msg != "" {
		return response.ErrBadRequest(msg)
	}

	userId := middleware.GetUserId(l.ctx)

	if l.svcCtx.TokenOpLimiter != nil {
		code, _ := l.svcCtx.TokenOpLimiter.Take(fmt.Sprintf("chpwd:%d", userId))
		if code == limit.OverQuota {
			return response.ErrTooManyRequests("操作过于频繁，请稍后再试")
		}
	}

	user, err := l.svcCtx.SysUserModel.FindOne(l.ctx, userId)
	if err != nil {
		return response.ErrNotFound("用户不存在")
	}

	if user.Status != consts.StatusEnabled {
		return response.ErrForbidden("账号已被冻结")
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(req.OldPassword)); err != nil {
		logx.WithContext(l.ctx).Infof("change-password old-password mismatch userId=%d", userId)
		return response.ErrBadRequest("原密码错误")
	}

	if req.OldPassword == req.NewPassword {
		return response.ErrBadRequest("新密码不能与原密码相同")
	}

	hashed, err := bcrypt.GenerateFromPassword([]byte(req.NewPassword), bcrypt.DefaultCost)
	if err != nil {
		return err
	}

	if err := l.svcCtx.SysUserModel.UpdatePassword(l.ctx, userId, string(hashed), consts.MustChangePasswordNo); err != nil {
		// 审计 M-R10-4：与 UpdateUserLogic / UpdateRoleLogic / UpdateUserStatusLogic 口径对齐，
		// 把乐观锁失败显式映射成 409，避免 raw error 被 rest 框架兜成 500、前端错把"并发冲突"
		// 当作系统故障处理，告警看板也不会把这类事件归到 5xx 噪声池。
		if errors.Is(err, userModel.ErrUpdateConflict) {
			return response.ErrConflict("密码已被其他会话修改，请刷新后重试")
		}
		return err
	}

	l.svcCtx.UserDetailsLoader.Clean(l.ctx, userId)
	return nil
}