// Copyright 2024 PingCAP, Inc.
//
// 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.

// This package is defined to return image of components
package image

import (
	"fmt"

	"github.com/distribution/reference"
)

const (
	PD      Untagged = "pingcap/pd"
	TiDB    Untagged = "pingcap/tidb"
	TiKV    Untagged = "pingcap/tikv"
	TiFlash Untagged = "pingcap/tiflash"

	// TODO: use versioned image
	PrestopChecker Tagged = "pingcap/prestop-checker:latest"
)

// Tagged is image with image tag
type Tagged string

// Untagged is image without image tag
type Untagged string

// Note: img must be validated before calling Version
func (t Tagged) Image(img *string) string {
	image := string(t)
	if img != nil {
		image = *img
	}

	return image
}

// Note: img must be validated before calling Version
func (t Untagged) Image(img *string, version string) string {
	image := string(t)
	if img != nil {
		image = *img
	}
	s, err := withVersion(image, version)
	if err != nil {
		panic(err)
	}

	return s
}

func withVersion(img, version string) (string, error) {
	named, exist, err := validate(img)
	if err != nil {
		return "", err
	}
	if !exist {
		return img, nil
	}

	tagged, err := reference.WithTag(named, version)
	if err != nil {
		return "", fmt.Errorf("cannot override version: %w", err)
	}
	return tagged.String(), nil
}

func Validate(img string) error {
	_, _, err := validate(img)
	return err
}

func validate(img string) (_ reference.Named, isNamed bool, _ error) {
	repo, err := reference.Parse(img)
	if err != nil {
		return nil, false, err
	}

	if _, ok := repo.(reference.Tagged); ok {
		return nil, false, nil
	}

	if _, ok := repo.(reference.Digested); ok {
		return nil, false, nil
	}

	named, ok := repo.(reference.Named)
	if !ok {
		return nil, false, fmt.Errorf("reference is not named")
	}

	return named, true, nil
}