package handler

import (
	"context"
	"io"
	"os"

	"gitea.loveuer.com/loveuer/cluster/internal/database"
	"gitea.loveuer.com/loveuer/cluster/internal/model"
	"gitea.loveuer.com/loveuer/cluster/internal/rerr"

	"github.com/google/uuid"
	"gorm.io/gorm"
)

type uploadHandlerImpl struct{}

// NewUploadHandler creates a new upload handler
func NewUploadHandler() UploadHandler {
	return &uploadHandlerImpl{}
}

func (u *uploadHandlerImpl) UploadId() string {
	return uuid.New().String()
}

func (u *uploadHandlerImpl) Write(ctx context.Context, sessionID string, r io.Reader, start, end int) (int, *rerr.RepositoryError) {
	// Get upload session
	var session model.RegistryUploadSession
	if err := database.DB.Where("session_id = ?", sessionID).First(&session).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return 0, &rerr.RepositoryError{
				Status:  404,
				Code:    "BLOB_UPLOAD_UNKNOWN",
				Message: "upload session not found",
			}
		}
		return 0, rerr.ErrInternal(err)
	}

	// Open file for writing
	file, err := os.OpenFile(session.Path, os.O_WRONLY|os.O_CREATE, 0644)
	if err != nil {
		return 0, rerr.ErrInternal(err)
	}
	defer file.Close()

	// Seek to start position
	if _, err := file.Seek(int64(start), 0); err != nil {
		return 0, rerr.ErrInternal(err)
	}

	// Write data
	n, err := io.CopyN(file, r, int64(end-start+1))
	if err != nil && err != io.EOF {
		return 0, rerr.ErrInternal(err)
	}

	// Update session size
	session.Size = int64(start) + n
	if err := database.DB.Save(&session).Error; err != nil {
		return 0, rerr.ErrInternal(err)
	}

	return int(n), nil
}

func (u *uploadHandlerImpl) Done(ctx context.Context, blobHandler BlobHandler, sessionID string, r io.Reader, contentLength int, repo string, h model.Hash) *rerr.RepositoryError {
	// Get upload session
	var session model.RegistryUploadSession
	if err := database.DB.Where("session_id = ?", sessionID).First(&session).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return &rerr.RepositoryError{
				Status:  404,
				Code:    "BLOB_UPLOAD_UNKNOWN",
				Message: "upload session not found",
			}
		}
		return rerr.ErrInternal(err)
	}

	// Read from the uploaded file instead of the request body
	file, err := os.Open(session.Path)
	if err != nil {
		return rerr.ErrInternal(err)
	}
	defer file.Close()

	// Store blob
	if err := blobHandler.Put(ctx, repo, h, file); err != nil {
		return rerr.ErrInternal(err)
	}

	// Clean up upload session
	os.Remove(session.Path)
	database.DB.Delete(&session)

	return nil
}