package user

import (
	"context"
	"time"

	"perms-system-server/internal/consts"
	authHelper "perms-system-server/internal/logic/auth"
	"perms-system-server/internal/middleware"
	"perms-system-server/internal/model/userrole"
	"perms-system-server/internal/response"
	"perms-system-server/internal/svc"
	"perms-system-server/internal/types"

	"github.com/zeromicro/go-zero/core/logx"
	"github.com/zeromicro/go-zero/core/stores/sqlx"
)

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

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

// BindRoles 绑定用户角色。对指定用户在当前产品下做角色全量覆盖（diff 后批量新增/删除），支持权限级别校验防止越权分配。
func (l *BindRolesLogic) BindRoles(req *types.BindRolesReq) error {
	caller := middleware.GetUserDetails(l.ctx)
	if caller == nil {
		return response.ErrUnauthorized("未登录")
	}

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

	productCode := middleware.GetProductCode(l.ctx)
	if err := authHelper.CheckManageAccess(l.ctx, l.svcCtx, req.UserId, productCode, authHelper.WithPrefetchedTarget(targetUser)); err != nil {
		return err
	}

	member, err := l.svcCtx.SysProductMemberModel.FindOneByProductCodeUserId(l.ctx, productCode, req.UserId)
	if err != nil {
		return response.ErrBadRequest("目标用户不是当前产品的成员")
	}
	if member.Status != consts.StatusEnabled {
		return response.ErrBadRequest("目标用户的成员资格已被禁用")
	}

	roleIds := req.RoleIds
	if len(roleIds) > 0 {
		seen := make(map[int64]bool, len(roleIds))
		uniqueIds := make([]int64, 0, len(roleIds))
		for _, id := range roleIds {
			if !seen[id] {
				seen[id] = true
				uniqueIds = append(uniqueIds, id)
			}
		}
		roleIds = uniqueIds
	}

	if len(roleIds) > 0 {
		roles, err := l.svcCtx.SysRoleModel.FindByIds(l.ctx, roleIds)
		if err != nil {
			return err
		}
		if int64(len(roles)) != int64(len(roleIds)) {
			return response.ErrBadRequest("包含无效的角色ID")
		}
		for _, r := range roles {
			if r.ProductCode != productCode {
				return response.ErrBadRequest("不能绑定其他产品的角色")
			}
			if r.Status != consts.StatusEnabled {
				return response.ErrBadRequest("不能绑定已禁用的角色")
			}
			if err := authHelper.GuardRoleLevelAssignable(l.ctx, l.svcCtx, caller, r.PermsLevel); err != nil {
				return err
			}
		}
	}

	existingRoleIds, err := l.svcCtx.SysUserRoleModel.FindRoleIdsByUserIdForProduct(l.ctx, req.UserId, productCode)
	if err != nil {
		return err
	}

	existingSet := make(map[int64]bool, len(existingRoleIds))
	for _, id := range existingRoleIds {
		existingSet[id] = true
	}
	newSet := make(map[int64]bool, len(roleIds))
	for _, id := range roleIds {
		newSet[id] = true
	}

	var toAdd []int64
	for _, id := range roleIds {
		if !existingSet[id] {
			toAdd = append(toAdd, id)
		}
	}
	var toRemove []int64
	for _, id := range existingRoleIds {
		if !newSet[id] {
			toRemove = append(toRemove, id)
		}
	}

	if len(toAdd) == 0 && len(toRemove) == 0 {
		l.svcCtx.UserDetailsLoader.Clean(l.ctx, req.UserId)
		return nil
	}

	if err := l.svcCtx.SysUserRoleModel.TransactCtx(l.ctx, func(ctx context.Context, session sqlx.Session) error {
		if err := l.svcCtx.SysUserRoleModel.DeleteByUserIdAndRoleIdsTx(ctx, session, req.UserId, toRemove); err != nil {
			return err
		}
		if len(toAdd) > 0 {
			now := time.Now().Unix()
			data := make([]*userrole.SysUserRole, 0, len(toAdd))
			for _, roleId := range toAdd {
				data = append(data, &userrole.SysUserRole{
					UserId:     req.UserId,
					RoleId:     roleId,
					CreateTime: now,
					UpdateTime: now,
				})
			}
			return l.svcCtx.SysUserRoleModel.BatchInsertWithTx(ctx, session, data)
		}
		return nil
	}); err != nil {
		return err
	}

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