package feed

import (
	"fmt"
	"net/http"
	"strings"
)

type dockerHubRepositoryTagsResponse struct {
	Results []dockerHubRepositoryTagResponse `json:"results"`
}

type dockerHubRepositoryTagResponse struct {
	Name       string `json:"name"`
	LastPushed string `json:"tag_last_pushed"`
}

const dockerHubOfficialRepoTagURLFormat = "https://hub.docker.com/_/%s/tags?name=%s"
const dockerHubRepoTagURLFormat = "https://hub.docker.com/r/%s/tags?name=%s"
const dockerHubTagsURLFormat = "https://hub.docker.com/v2/namespaces/%s/repositories/%s/tags"
const dockerHubSpecificTagURLFormat = "https://hub.docker.com/v2/namespaces/%s/repositories/%s/tags/%s"

func fetchLatestDockerHubRelease(request *ReleaseRequest) (*AppRelease, error) {

	nameParts := strings.Split(request.Repository, "/")

	if len(nameParts) > 2 {
		return nil, fmt.Errorf("invalid repository name: %s", request.Repository)
	} else if len(nameParts) == 1 {
		nameParts = []string{"library", nameParts[0]}
	}

	tagParts := strings.SplitN(nameParts[1], ":", 2)

	var requestURL string

	if len(tagParts) == 2 {
		requestURL = fmt.Sprintf(dockerHubSpecificTagURLFormat, nameParts[0], tagParts[0], tagParts[1])
	} else {
		requestURL = fmt.Sprintf(dockerHubTagsURLFormat, nameParts[0], nameParts[1])
	}

	httpRequest, err := http.NewRequest("GET", requestURL, nil)

	if err != nil {
		return nil, err
	}

	if request.Token != nil {
		httpRequest.Header.Add("Authorization", "Bearer "+(*request.Token))
	}

	var tag *dockerHubRepositoryTagResponse

	if len(tagParts) == 1 {
		response, err := decodeJsonFromRequest[dockerHubRepositoryTagsResponse](defaultClient, httpRequest)

		if err != nil {
			return nil, err
		}

		if len(response.Results) == 0 {
			return nil, fmt.Errorf("no tags found for repository: %s", request.Repository)
		}

		tag = &response.Results[0]
	} else {
		response, err := decodeJsonFromRequest[dockerHubRepositoryTagResponse](defaultClient, httpRequest)

		if err != nil {
			return nil, err
		}

		tag = &response
	}

	var repo string
	var displayName string
	var notesURL string

	if len(tagParts) == 1 {
		repo = nameParts[1]
	} else {
		repo = tagParts[0]
	}

	if nameParts[0] == "library" {
		displayName = repo
		notesURL = fmt.Sprintf(dockerHubOfficialRepoTagURLFormat, repo, tag.Name)
	} else {
		displayName = nameParts[0] + "/" + repo
		notesURL = fmt.Sprintf(dockerHubRepoTagURLFormat, displayName, tag.Name)
	}

	return &AppRelease{
		Source:       ReleaseSourceDockerHub,
		NotesUrl:     notesURL,
		Name:         displayName,
		Version:      tag.Name,
		TimeReleased: parseRFC3339Time(tag.LastPushed),
	}, nil
}