package repository

import (
	"context"
	"errors"

	"gorm.io/gorm"

	"github.com/dhao2001/mygo/internal/model"
)

// FileRepository provides access to file records.
type FileRepository interface {
	Create(ctx context.Context, file *model.File) error
	FindByID(ctx context.Context, id string) (*model.File, error)
	FindByUserID(ctx context.Context, userID string, offset, limit int) ([]model.File, int64, error)
	FindByParentID(ctx context.Context, userID string, parentID *string) ([]model.File, error)
	Update(ctx context.Context, file *model.File) error
	Delete(ctx context.Context, id string) error
}

type fileRepository struct {
	db *gorm.DB
}

// NewFileRepository creates a FileRepository backed by GORM.
func NewFileRepository(db *gorm.DB) FileRepository {
	return &fileRepository{db: db}
}

func (r *fileRepository) Create(ctx context.Context, file *model.File) error {
	result := r.db.WithContext(ctx).Create(file)
	if result.Error != nil {
		if isDuplicateKeyError(result.Error) {
			return model.ErrDuplicate
		}
		return result.Error
	}
	return nil
}

func (r *fileRepository) FindByID(ctx context.Context, id string) (*model.File, error) {
	var file model.File
	result := r.db.WithContext(ctx).First(&file, "id = ?", id)
	if errors.Is(result.Error, gorm.ErrRecordNotFound) {
		return nil, model.ErrNotFound
	}
	if result.Error != nil {
		return nil, result.Error
	}
	return &file, nil
}

func (r *fileRepository) FindByUserID(ctx context.Context, userID string, offset, limit int) ([]model.File, int64, error) {
	var files []model.File
	var total int64

	if err := r.db.WithContext(ctx).Model(&model.File{}).Where("user_id = ?", userID).Count(&total).Error; err != nil {
		return nil, 0, err
	}

	result := r.db.WithContext(ctx).Where("user_id = ?", userID).Offset(offset).Limit(limit).Find(&files)
	if result.Error != nil {
		return nil, 0, result.Error
	}

	return files, total, nil
}

func (r *fileRepository) FindByParentID(ctx context.Context, userID string, parentID *string) ([]model.File, error) {
	var files []model.File
	result := r.db.WithContext(ctx).Where("user_id = ? AND parent_id IS ?", userID, parentID).Find(&files)
	if result.Error != nil {
		return nil, result.Error
	}
	return files, nil
}

func (r *fileRepository) Update(ctx context.Context, file *model.File) error {
	result := r.db.WithContext(ctx).Save(file)
	if result.Error != nil {
		return result.Error
	}
	return nil
}

func (r *fileRepository) Delete(ctx context.Context, id string) error {
	result := r.db.WithContext(ctx).Delete(&model.File{}, "id = ?", id)
	if result.Error != nil {
		return result.Error
	}
	return nil
}