package repository

import (
	"metazone.cc/metalab/internal/model"

	"gorm.io/gorm"
)

// PostRepo 帖子数据访问
type PostRepo struct {
	db *gorm.DB
}

// NewPostRepo 构造函数
func NewPostRepo(db *gorm.DB) *PostRepo {
	return &PostRepo{db: db}
}

// Create 创建帖子
func (r *PostRepo) Create(post *model.Post) error {
	return r.db.Create(post).Error
}

// FindByID 按 ID 查找帖子
func (r *PostRepo) FindByID(id uint) (*model.Post, error) {
	var post model.Post
	err := r.db.First(&post, id).Error
	if err != nil {
		return nil, err
	}
	return &post, nil
}

// FindByIDWithAuthor 按 ID 查找帖子（含作者用户名）
func (r *PostRepo) FindByIDWithAuthor(id uint) (*model.Post, error) {
	var post model.Post
	err := r.db.Table("posts").
		Select("posts.*, users.username as author_name").
		Joins("LEFT JOIN users ON users.uid = posts.user_id").
		Where("posts.id = ?", id).
		First(&post).Error
	if err != nil {
		return nil, err
	}
	return &post, nil
}

// buildQuery 构建帖子查询公共部分（联表 + 未删除 + 关键词 + 可选状态过滤）
func (r *PostRepo) buildQuery(keyword, status string) *gorm.DB {
	query := r.db.Table("posts").
		Select("posts.*, users.username as author_name").
		Joins("LEFT JOIN users ON users.uid = posts.user_id").
		Where("posts.deleted_at IS NULL")

	if keyword != "" {
		like := "%" + keyword + "%"
		query = query.Where("posts.title LIKE ?", like)
	}
	if status != "" {
		query = query.Where("posts.status = ?", status)
	}
	return query
}

// FindPageable 分页查询帖子列表（仅 approved 状态，关键词模糊搜索标题）
func (r *PostRepo) FindPageable(keyword string, offset, limit int) ([]model.Post, int64, error) {
	query := r.buildQuery(keyword, model.PostStatusApproved)
	return r.pageResults(query, offset, limit)
}

// FindAdminPageable 管理后台分页查询（全状态筛选，待审置顶）
func (r *PostRepo) FindAdminPageable(keyword, status string, offset, limit int) ([]model.Post, int64, error) {
	query := r.buildQuery(keyword, status)
	return r.pageResultsAdmin(query, offset, limit)
}

// FindByUserID 分页查询某用户发布的帖子（仅 approved，含作者用户名）
func (r *PostRepo) FindByUserID(userID uint, offset, limit int) ([]model.Post, int64, error) {
	query := r.buildQuery("", model.PostStatusApproved).
		Where("posts.user_id = ?", userID)
	return r.pageResults(query, offset, limit)
}

// FindByUserIDAndStatus 分页查询某用户指定状态的帖子（空 status=全状态）
func (r *PostRepo) FindByUserIDAndStatus(userID uint, status string, offset, limit int) ([]model.Post, int64, error) {
	query := r.buildQuery("", status).
		Where("posts.user_id = ?", userID)
	return r.pageResults(query, offset, limit)
}

// FindPendingRevisions 查询有待审修订的帖子（approved 且 pending_body 不为空）
func (r *PostRepo) FindPendingRevisions(keyword string, offset, limit int) ([]model.Post, int64, error) {
	query := r.buildQuery(keyword, model.PostStatusApproved).
		Where("posts.pending_body != ''")
	return r.pageResults(query, offset, limit)
}

// pageResults 执行 Count + Offset/Limit + ORDER BY
func (r *PostRepo) pageResults(query *gorm.DB, offset, limit int) ([]model.Post, int64, error) {
	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	var posts []model.Post
	err := query.Order("posts.created_at DESC").
		Offset(offset).Limit(limit).Find(&posts).Error
	if err != nil {
		return nil, 0, err
	}
	return posts, total, nil
}

// pageResultsAdmin 管理后台分页：待审稿件（pending 或 修订待审）置顶优先
func (r *PostRepo) pageResultsAdmin(query *gorm.DB, offset, limit int) ([]model.Post, int64, error) {
	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	var posts []model.Post
	err := query.Order(`CASE WHEN posts.status = 'pending' OR (posts.status = 'approved' AND posts.pending_body != '') THEN 0 ELSE 1 END ASC, posts.created_at DESC`).
		Offset(offset).Limit(limit).Find(&posts).Error
	if err != nil {
		return nil, 0, err
	}
	return posts, total, nil
}

// Update 更新帖子
func (r *PostRepo) Update(post *model.Post) error {
	return r.db.Save(post).Error
}

// SoftDelete 软删除帖子
func (r *PostRepo) SoftDelete(id uint) error {
	return r.db.Delete(&model.Post{}, id).Error
}

// Restore 恢复软删除
func (r *PostRepo) Restore(id uint) error {
	result := r.db.Unscoped().Model(&model.Post{}).Where("id = ?", id).Update("deleted_at", nil)
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return gorm.ErrRecordNotFound
	}
	return nil
}
