package repository

import (
	"errors"

	"with_you/internal/model"

	"gorm.io/gorm"
)

type GroupJoinRequestRepository interface {
	Create(req *model.GroupJoinRequest) error
	GetByFlag(flag string) (*model.GroupJoinRequest, error)
	Update(req *model.GroupJoinRequest) error
	GetPendingByGroupAndTarget(groupID, targetUserID string, reqType model.GroupJoinRequestType) (*model.GroupJoinRequest, error)
	GetPendingByGroupAndTargets(groupID string, targetUserIDs []string, reqType model.GroupJoinRequestType) (map[string]bool, error)
}

type groupJoinRequestRepository struct {
	db *gorm.DB
}

func NewGroupJoinRequestRepository(db *gorm.DB) GroupJoinRequestRepository {
	return &groupJoinRequestRepository{db: db}
}

func (r *groupJoinRequestRepository) Create(req *model.GroupJoinRequest) error {
	return r.db.Create(req).Error
}

func (r *groupJoinRequestRepository) GetByFlag(flag string) (*model.GroupJoinRequest, error) {
	var req model.GroupJoinRequest
	if err := r.db.Where("flag = ?", flag).First(&req).Error; err != nil {
		return nil, err
	}
	return &req, nil
}

func (r *groupJoinRequestRepository) Update(req *model.GroupJoinRequest) error {
	return r.db.Save(req).Error
}

func (r *groupJoinRequestRepository) GetPendingByGroupAndTarget(groupID, targetUserID string, reqType model.GroupJoinRequestType) (*model.GroupJoinRequest, error) {
	var req model.GroupJoinRequest
	err := r.db.Where("group_id = ? AND target_user_id = ? AND request_type = ? AND status = ?",
		groupID, targetUserID, reqType, model.GroupJoinRequestStatusPending).
		Order("created_at DESC").
		First(&req).Error
	if err != nil {
		return nil, err
	}
	return &req, nil
}

func (r *groupJoinRequestRepository) GetPendingByGroupAndTargets(groupID string, targetUserIDs []string, reqType model.GroupJoinRequestType) (map[string]bool, error) {
	result := make(map[string]bool)
	if len(targetUserIDs) == 0 {
		return result, nil
	}
	var existingIDs []string
	err := r.db.Model(&model.GroupJoinRequest{}).
		Where("group_id = ? AND target_user_id IN ? AND request_type = ? AND status = ?",
			groupID, targetUserIDs, reqType, model.GroupJoinRequestStatusPending).
		Pluck("target_user_id", &existingIDs).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return result, nil
		}
		return nil, err
	}
	for _, id := range existingIDs {
		result[id] = true
	}
	return result, nil
}