package repository

import (
	"context"

	"with_you/internal/model"
	"with_you/internal/pkg/cursor"

	"gorm.io/gorm"
)

type TradeRepository interface {
	Create(ctx context.Context, item *model.TradeItem, imageUrls []string) error
	GetByID(ctx context.Context, id string) (*model.TradeItem, error)
	Update(ctx context.Context, item *model.TradeItem) error
	UpdateWithImages(ctx context.Context, item *model.TradeItem, imageUrls *[]string) error
	Delete(ctx context.Context, id string) error
	UpdateStatus(ctx context.Context, id string, status model.TradeItemStatus) error
	ListByCursor(ctx context.Context, tradeType *model.TradeType, category *model.TradeCategory, status *model.TradeItemStatus, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error)
	SearchByCursor(ctx context.Context, keyword string, tradeType *model.TradeType, category *model.TradeCategory, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error)
	ListByUserByCursor(ctx context.Context, userID string, status *model.TradeItemStatus, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error)
	IncrementViews(ctx context.Context, id string) error
	IncrementFavorites(ctx context.Context, id string) error
	DecrementFavorites(ctx context.Context, id string) error

	CreateFavorite(ctx context.Context, tradeItemID, userID string) error
	DeleteFavorite(ctx context.Context, tradeItemID, userID string) error
	IsFavorited(ctx context.Context, tradeItemID, userID string) (bool, error)
	IsFavoritedBatch(ctx context.Context, tradeItemIDs []string, userID string) (map[string]bool, error)
}

type tradeRepository struct {
	db *gorm.DB
}

func NewTradeRepository(db *gorm.DB) TradeRepository {
	return &tradeRepository{db: db}
}

func (r *tradeRepository) getDB(ctx context.Context) *gorm.DB {
	if tx := GetTxFromContext(ctx); tx != nil {
		return tx
	}
	return r.db
}

func (r *tradeRepository) Create(ctx context.Context, item *model.TradeItem, imageUrls []string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Create(item).Error; err != nil {
			return err
		}
		for i, url := range imageUrls {
			img := model.TradeImage{
				TradeItemID: item.ID,
				URL:          url,
				SortOrder:    i,
			}
			if err := tx.Create(&img).Error; err != nil {
				return err
			}
		}
		return nil
	})
}

func (r *tradeRepository) GetByID(ctx context.Context, id string) (*model.TradeItem, error) {
	db := r.getDB(ctx).WithContext(ctx)
	var item model.TradeItem
	if err := db.Preload("User").Preload("Images", func(db *gorm.DB) *gorm.DB {
		return db.Order("sort_order ASC")
	}).First(&item, "id = ?", id).Error; err != nil {
		return nil, err
	}
	return &item, nil
}

func (r *tradeRepository) Update(ctx context.Context, item *model.TradeItem) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Save(item).Error
}

func (r *tradeRepository) UpdateWithImages(ctx context.Context, item *model.TradeItem, imageUrls *[]string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Save(item).Error; err != nil {
			return err
		}
		if imageUrls != nil {
			if err := tx.Where("trade_item_id = ?", item.ID).Delete(&model.TradeImage{}).Error; err != nil {
				return err
			}
			for i, url := range *imageUrls {
				img := model.TradeImage{
					TradeItemID: item.ID,
					URL:          url,
					SortOrder:    i,
				}
				if err := tx.Create(&img).Error; err != nil {
					return err
				}
			}
		}
		return nil
	})
}

func (r *tradeRepository) Delete(ctx context.Context, id string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("trade_item_id = ?", id).Delete(&model.TradeImage{}).Error; err != nil {
			return err
		}
		if err := tx.Where("trade_item_id = ?", id).Delete(&model.TradeFavorite{}).Error; err != nil {
			return err
		}
		return tx.Delete(&model.TradeItem{}, "id = ?", id).Error
	})
}

func (r *tradeRepository) UpdateStatus(ctx context.Context, id string, status model.TradeItemStatus) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Model(&model.TradeItem{}).Where("id = ?", id).Update("status", status).Error
}

func (r *tradeRepository) ListByCursor(ctx context.Context, tradeType *model.TradeType, category *model.TradeCategory, status *model.TradeItemStatus, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error) {
	db := r.getDB(ctx).WithContext(ctx)
	query := db.Model(&model.TradeItem{})

	if tradeType != nil {
		query = query.Where("trade_type = ?", *tradeType)
	}
	if category != nil {
		query = query.Where("category = ?", *category)
	}
	defaultStatus := model.TradeItemActive
	if status != nil {
		defaultStatus = *status
	}
	query = query.Where("status = ?", defaultStatus)

	builder := cursor.NewBuilder(query, cursor.SortByCreatedAtDesc).
		WithCursor(req.Cursor, req.Direction).
		WithPageSize(req.PageSize)

	if builder.Error() != nil {
		return cursor.NewCursorPageResult([]*model.TradeItem{}, "", "", false), nil
	}

	var items []*model.TradeItem
	q := builder.Build().Preload("User").Preload("Images", func(db *gorm.DB) *gorm.DB {
		return db.Order("sort_order ASC")
	})
	if err := q.Find(&items).Error; err != nil {
		return nil, err
	}

	pageSize := builder.GetPageSize()
	hasMore := cursor.HasMore(len(items), pageSize)
	if hasMore {
		items = items[:pageSize]
	}

	var nextCursor, prevCursor string
	if len(items) > 0 {
		if hasMore {
			last := items[len(items)-1]
			nextCursor = cursor.NewCursor(cursor.FormatTime(last.CreatedAt), last.ID, cursor.SortByCreatedAtDesc).Encode()
		}
		first := items[0]
		prevCursor = cursor.NewCursor(cursor.FormatTime(first.CreatedAt), first.ID, cursor.SortByCreatedAtDesc).Encode()
	}

	return cursor.NewCursorPageResult(items, nextCursor, prevCursor, hasMore), nil
}

func (r *tradeRepository) SearchByCursor(ctx context.Context, keyword string, tradeType *model.TradeType, category *model.TradeCategory, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error) {
	db := r.getDB(ctx).WithContext(ctx)
	query := db.Model(&model.TradeItem{}).Where("status = ?", model.TradeItemActive)

	if tradeType != nil {
		query = query.Where("trade_type = ?", *tradeType)
	}
	if category != nil {
		query = query.Where("category = ?", *category)
	}
	if keyword != "" {
		searchPattern := "%" + keyword + "%"
		query = query.Where("title LIKE ? OR content LIKE ?", searchPattern, searchPattern)
	}

	builder := cursor.NewBuilder(query, cursor.SortByCreatedAtDesc).
		WithCursor(req.Cursor, req.Direction).
		WithPageSize(req.PageSize)

	if builder.Error() != nil {
		return cursor.NewCursorPageResult([]*model.TradeItem{}, "", "", false), nil
	}

	var items []*model.TradeItem
	q := builder.Build().Preload("User").Preload("Images", func(db *gorm.DB) *gorm.DB {
		return db.Order("sort_order ASC")
	})
	if err := q.Find(&items).Error; err != nil {
		return nil, err
	}

	pageSize := builder.GetPageSize()
	hasMore := cursor.HasMore(len(items), pageSize)
	if hasMore {
		items = items[:pageSize]
	}

	var nextCursor, prevCursor string
	if len(items) > 0 {
		if hasMore {
			last := items[len(items)-1]
			nextCursor = cursor.NewCursor(cursor.FormatTime(last.CreatedAt), last.ID, cursor.SortByCreatedAtDesc).Encode()
		}
		first := items[0]
		prevCursor = cursor.NewCursor(cursor.FormatTime(first.CreatedAt), first.ID, cursor.SortByCreatedAtDesc).Encode()
	}

	return cursor.NewCursorPageResult(items, nextCursor, prevCursor, hasMore), nil
}

func (r *tradeRepository) ListByUserByCursor(ctx context.Context, userID string, status *model.TradeItemStatus, req *cursor.PageRequest) (*cursor.CursorPageResult[*model.TradeItem], error) {
	db := r.getDB(ctx).WithContext(ctx)
	query := db.Model(&model.TradeItem{}).Where("user_id = ?", userID)

	if status != nil {
		query = query.Where("status = ?", *status)
	}

	builder := cursor.NewBuilder(query, cursor.SortByCreatedAtDesc).
		WithCursor(req.Cursor, req.Direction).
		WithPageSize(req.PageSize)

	if builder.Error() != nil {
		return cursor.NewCursorPageResult([]*model.TradeItem{}, "", "", false), nil
	}

	var items []*model.TradeItem
	q := builder.Build().Preload("User").Preload("Images", func(db *gorm.DB) *gorm.DB {
		return db.Order("sort_order ASC")
	})
	if err := q.Find(&items).Error; err != nil {
		return nil, err
	}

	pageSize := builder.GetPageSize()
	hasMore := cursor.HasMore(len(items), pageSize)
	if hasMore {
		items = items[:pageSize]
	}

	var nextCursor, prevCursor string
	if len(items) > 0 {
		if hasMore {
			last := items[len(items)-1]
			nextCursor = cursor.NewCursor(cursor.FormatTime(last.CreatedAt), last.ID, cursor.SortByCreatedAtDesc).Encode()
		}
		first := items[0]
		prevCursor = cursor.NewCursor(cursor.FormatTime(first.CreatedAt), first.ID, cursor.SortByCreatedAtDesc).Encode()
	}

	return cursor.NewCursorPageResult(items, nextCursor, prevCursor, hasMore), nil
}

func (r *tradeRepository) IncrementViews(ctx context.Context, id string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Model(&model.TradeItem{}).Where("id = ?", id).UpdateColumn("views_count", gorm.Expr("views_count + 1")).Error
}

func (r *tradeRepository) IncrementFavorites(ctx context.Context, id string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Model(&model.TradeItem{}).Where("id = ?", id).UpdateColumn("favorites_count", gorm.Expr("favorites_count + 1")).Error
}

func (r *tradeRepository) DecrementFavorites(ctx context.Context, id string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Model(&model.TradeItem{}).Where("id = ? AND favorites_count > 0", id).UpdateColumn("favorites_count", gorm.Expr("favorites_count - 1")).Error
}

func (r *tradeRepository) CreateFavorite(ctx context.Context, tradeItemID, userID string) error {
	db := r.getDB(ctx).WithContext(ctx)
	fav := model.TradeFavorite{
		TradeItemID: tradeItemID,
		UserID:      userID,
	}
	return db.Create(&fav).Error
}

func (r *tradeRepository) DeleteFavorite(ctx context.Context, tradeItemID, userID string) error {
	db := r.getDB(ctx).WithContext(ctx)
	return db.Where("trade_item_id = ? AND user_id = ?", tradeItemID, userID).Delete(&model.TradeFavorite{}).Error
}

func (r *tradeRepository) IsFavorited(ctx context.Context, tradeItemID, userID string) (bool, error) {
	db := r.getDB(ctx).WithContext(ctx)
	var count int64
	if err := db.Model(&model.TradeFavorite{}).Where("trade_item_id = ? AND user_id = ?", tradeItemID, userID).Count(&count).Error; err != nil {
		return false, err
	}
	return count > 0, nil
}

func (r *tradeRepository) IsFavoritedBatch(ctx context.Context, tradeItemIDs []string, userID string) (map[string]bool, error) {
	db := r.getDB(ctx).WithContext(ctx)
	result := make(map[string]bool, len(tradeItemIDs))
	if len(tradeItemIDs) == 0 {
		return result, nil
	}
	for _, id := range tradeItemIDs {
		result[id] = false
	}
	var favorites []model.TradeFavorite
	if err := db.Where("trade_item_id IN ? AND user_id = ?", tradeItemIDs, userID).Find(&favorites).Error; err != nil {
		return nil, err
	}
	for _, fav := range favorites {
		result[fav.TradeItemID] = true
	}
	return result, nil
}