// Copyright 2022 Linka Cloud  All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package d2vm

import (
	"context"
	"fmt"
	"io"
	"os"
	"path/filepath"

	"github.com/google/uuid"
	"github.com/sirupsen/logrus"

	"go.linka.cloud/d2vm/pkg/docker"
)

func Convert(ctx context.Context, img string, size int64, password string, output string, format string) error {
	imgUUID := uuid.New().String()
	tmpPath := filepath.Join(os.TempDir(), "d2vm", imgUUID)
	if err := os.MkdirAll(tmpPath, os.ModePerm); err != nil {
		return err
	}
	defer os.RemoveAll(tmpPath)

	logrus.Infof("inspecting image %s", img)
	r, err := FetchDockerImageOSRelease(ctx, img, tmpPath)
	if err != nil {
		return err
	}
	d, err := NewDockerfile(r, img, password)
	if err != nil {
		return err
	}
	logrus.Infof("docker image based on %s", d.Release.Name)
	p := filepath.Join(tmpPath, docker.FormatImgName(img))
	dir := filepath.Dir(p)
	f, err := os.Create(p)
	if err != nil {
		return err
	}
	defer f.Close()
	if err := d.Render(f); err != nil {
		return err
	}
	logrus.Infof("building kernel enabled image")
	if err := docker.Cmd(ctx, "image", "build", "-t", imgUUID, "-f", p, dir); err != nil {
		return err
	}
	defer docker.Cmd(ctx, "image", "rm", imgUUID)

	logrus.Infof("creating vm image")
	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", size, r, format)
	if err != nil {
		return err
	}
	defer b.Close()
	if err := b.Build(ctx); err != nil {
		return err
	}
	if err := os.RemoveAll(output); err != nil {
		return err
	}
	if err := MoveFile(filepath.Join(tmpPath, "disk0.qcow2"), output); err != nil {
		return err
	}
	return nil
}

func MoveFile(sourcePath, destPath string) error {
	inputFile, err := os.Open(sourcePath)
	if err != nil {
		return fmt.Errorf("failed to open source file: %s", err)
	}
	outputFile, err := os.Create(destPath)
	if err != nil {
		inputFile.Close()
		return fmt.Errorf("failed to open dest file: %s", err)
	}
	defer outputFile.Close()
	_, err = io.Copy(outputFile, inputFile)
	inputFile.Close()
	if err != nil {
		return fmt.Errorf("failed to write to output file: %s", err)
	}
	// The copy was successful, so now delete the original file
	err = os.Remove(sourcePath)
	if err != nil {
		return fmt.Errorf("failed to remove original file: %s", err)
	}
	return nil
}