package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"

	"codeberg.org/woodpecker-plugins/go-plugin"
	"github.com/rs/zerolog/log"
	"github.com/urfave/cli/v2"
)

type Settings struct {
	Token     string
	ImageName string
	Tag       string
	Region    string
}

type Plugin struct {
	*plugin.Plugin
	Settings *Settings
}

func (p *Plugin) Flags() []cli.Flag {
	return []cli.Flag{
		&cli.StringFlag{
			Name:        "token",
			Usage:       "Token for the Scaleway API",
			EnvVars:     []string{"PLUGIN_TOKEN"},
			Destination: &p.Settings.Token,
		},
		&cli.StringFlag{
			Name:        "image-name",
			Usage:       "The image from which the tag should be deleted",
			EnvVars:     []string{"PLUGIN_IMAGE_NAME"},
			Destination: &p.Settings.ImageName,
		},
		&cli.StringFlag{
			Name:        "tag",
			Usage:       "The tag that should be deleted",
			EnvVars:     []string{"PLUGIN_TAG"},
			Destination: &p.Settings.Tag,
		},
		&cli.StringFlag{
			Name:        "region",
			Usage:       "The Scaleway region the registry exists",
			EnvVars:     []string{"PLUGIN_REGION"},
			Destination: &p.Settings.Region,
		},
	}
}

func (p *Plugin) Execute(ctx context.Context) error {
	missingFlags := requiredFlags(p.Settings)
	if len(missingFlags) != 0 {
		log.Error().Msg("following flags are missing:")
		for _, errMsg := range missingFlags {
			log.Error().Msg("-" + errMsg)
		}
		return errors.New("missing required flags")
	}
	log.Info().Msg("start")
	token := p.Settings.Token
	region := p.Settings.Region
	imageName := p.Settings.ImageName
	log.Debug().Msg("get image id")
	imageId, err := getImageId(region, imageName, token)
	if err != nil {
		return fmt.Errorf("get image id: %w", err)
	}
	tagName := p.Settings.Tag
	log.Debug().Msg("get tag id")
	tagId, err := getImageTagId(region, tagName, imageId, token)
	if err != nil {
		return fmt.Errorf("get tag id: %w", err)
	}
	log.Debug().Msg("delete image id")
	err = deleteImageTagById(region, tagId, token)
	if err != nil {
		return fmt.Errorf("delete tag id: %w", err)
	}
	log.Info().Msg("finish")
	return nil
}

func requiredFlags(settings *Settings) []string {
	var errorList []string
	if settings.ImageName == "" {
		errorList = append(errorList, "image-name")
	}
	if settings.Tag == "" {
		errorList = append(errorList, "tag")
	}
	if settings.Region == "" {
		errorList = append(errorList, "region")
	}
	if settings.Token == "" {
		errorList = append(errorList, "token")
	}
	return errorList
}

func main() {
	p := &Plugin{
		Settings: &Settings{},
	}

	p.Plugin = plugin.New(plugin.Options{
		Name:        "Scaleway Delete Image Plugin",
		Description: "Automatically delete image tags from Scaleway registry",
		Flags:       p.Flags(),
		Execute:     p.Execute,
	})

	p.Run()
}

type ImagesResponse struct {
	Images []Image `json:"images"`
}

type Image struct {
	Id string `json:"id"`
}

func getImageId(region, imageName, token string) (string, error) {
	url := fmt.Sprintf("https://api.scaleway.com/registry/v1/regions/%s/images?name=%s", region, imageName)
	res, err := doRequest(http.MethodGet, url, token)
	if err != nil {
		return "", fmt.Errorf("get request for image id: %w", err)
	}
	defer closeLogger(res.Body)
	if res.StatusCode != 200 {
		return "", fmt.Errorf("expected status code 200 but got: %d", res.StatusCode)
	}

	body, err := io.ReadAll(res.Body)
	if err != nil {
		return "", fmt.Errorf("reading response body for image id: %w", err)
	}
	var imagesResponse ImagesResponse
	err = json.Unmarshal(body, &imagesResponse)
	if err != nil {
		return "", fmt.Errorf("unmarshal body for image id: %w", err)
	}
	if len(imagesResponse.Images) != 1 {
		return "", fmt.Errorf("expected 1 image but found '%d' with the name: %s", len(imagesResponse.Images), imageName)
	}

	return imagesResponse.Images[0].Id, nil
}

type TagsResponse struct {
	Tags []Tag `json:"tags"`
}

type Tag struct {
	Id string `json:"id"`
}

func getImageTagId(region, tagName, imageId, token string) (string, error) {
	url := fmt.Sprintf("https://api.scaleway.com/registry/v1/regions/%s/images/%s/tags?name=%s", region, imageId, tagName)
	res, err := doRequest(http.MethodGet, url, token)
	if err != nil {
		return "", fmt.Errorf("get request tag id: %w", err)
	}
	defer closeLogger(res.Body)
	if res.StatusCode != 200 {
		return "", fmt.Errorf("expected status code 200 but got: %d", res.StatusCode)
	}

	body, err := io.ReadAll(res.Body)
	if err != nil {
		return "", fmt.Errorf("reading response body for tag id: %w", err)
	}
	var tagsResponse TagsResponse
	err = json.Unmarshal(body, &tagsResponse)
	if err != nil {
		return "", fmt.Errorf("unmarshal body for tag id: %w", err)
	}
	if len(tagsResponse.Tags) != 1 {
		return "", fmt.Errorf("expected 1 but found '%d' with name: %s", len(tagsResponse.Tags), tagName)
	}

	return tagsResponse.Tags[0].Id, nil
}

func deleteImageTagById(region, tagId, token string) error {
	url := fmt.Sprintf("https://api.scaleway.com/registry/v1/regions/%s/tags/%s", region, tagId)
	res, err := doRequest(http.MethodDelete, url, token)
	if err != nil {
		return fmt.Errorf("deleting tag id: %w", err)
	}
	defer closeLogger(res.Body)
	if res.StatusCode != 200 {
		return fmt.Errorf("expected status code 200 but got: %d", res.StatusCode)
	}

	return nil
}

func closeLogger(closer io.Closer) {
	err := closer.Close()
	if err != nil {
		log.Warn().Msgf("closing io operation: %s", err.Error())
	}
}

func doRequest(method, url, token string) (*http.Response, error) {
	req, err := http.NewRequest(method, url, nil)
	if err != nil {
		return nil, fmt.Errorf("building request: %w", err)
	}
	req.Header.Set("X-Auth-Token", token)

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("making request: %w", err)
	}
	return res, nil
}