package catalogue

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"strings"
	"time"

	"coopcloud.tech/abra/config"
	"coopcloud.tech/abra/web"
	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing"
)

type Image struct {
	Image  string `json:"image"`
	Rating string `json:"rating"`
	Source string `json:"source"`
	URL    string `json:"url"`
}

// Feature represents a JSON struct for a recipes features
type Feature struct {
	Backups     string `json:"backups"`
	Email       string `json:"email"`
	Healthcheck string `json:"healthcheck"`
	Image       Image  `json:"image"`
	Status      int    `json:"status"`
	Tests       string `json:"tests"`
}

// Tag represents a git tag
type Tag = string
type Service = string
type ServiceMeta struct {
	Digest string `json:"digest"`
	Image  string `json:"image"`
	Tag    string `json:"tag"`
}

// App reprents an App in the abra catalogue
type App struct {
	Category      string                          `json:"category"`
	DefaultBranch string                          `json:"default_branch"`
	Description   string                          `json:"description"`
	Features      Feature                         `json:"features"`
	Icon          string                          `json:"icon"`
	Name          string                          `json:"name"`
	Repository    string                          `json:"repository"`
	Versions      map[Tag]map[Service]ServiceMeta `json:"versions"`
	Website       string                          `json:"website"`
}

// EnsureExists checks the app has been cloned locally
func (a App) EnsureExists() error {
	appDir := path.Join(config.ABRA_DIR, "apps", strings.ToLower(a.Name))
	if _, err := os.Stat(appDir); os.IsNotExist(err) {
		url := fmt.Sprintf("%s/%s.git", config.REPOS_BASE_URL, a.Name)
		_, err := git.PlainClone(appDir, false, &git.CloneOptions{URL: url, Tags: git.AllTags})
		if err != nil {
			return err
		}
	}
	return nil
}

// EnsureVersion checks if an given version is used for the app
func (a App) EnsureVersion(version string) error {
	appDir := path.Join(config.ABRA_DIR, "apps", strings.ToLower(a.Name))

	repo, err := git.PlainOpen(appDir)
	if err != nil {
		return err
	}

	tags, err := repo.Tags()
	if err != nil {
		return nil
	}

	var tagRef plumbing.ReferenceName
	if err := tags.ForEach(func(ref *plumbing.Reference) (err error) {
		if ref.Name().Short() == version {
			tagRef = ref.Name()
		}
		return nil
	}); err != nil {
		return err
	}

	if tagRef.String() == "" {
		return fmt.Errorf("%s is not available?", version)
	}

	worktree, err := repo.Worktree()
	if err != nil {
		return err
	}

	opts := &git.CheckoutOptions{Branch: tagRef, Keep: true}
	if err := worktree.Checkout(opts); err != nil {
		return err
	}

	return nil
}

// LatestVersion returns the latest version of the app
func (a App) LatestVersion() string {
	var latestVersion string
	for tag := range a.Versions {
		// apps.json versions are sorted so the last key is latest
		latestVersion = tag
	}
	return latestVersion
}

type Name = string
type AppsCatalogue map[Name]App

// Flatten converts AppCatalogue to slice
func (a AppsCatalogue) Flatten() []App {
	apps := make([]App, 0, len(a))
	for name := range a {
		apps = append(apps, a[name])
	}
	return apps
}

type ByAppName []App

func (a ByAppName) Len() int      { return len(a) }
func (a ByAppName) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByAppName) Less(i, j int) bool {
	return strings.ToLower(a[i].Name) < strings.ToLower(a[j].Name)
}

var appsCatalogueURL = "https://apps.coopcloud.tech"

func appsCatalogueFSIsLatest() (bool, error) {
	httpClient := &http.Client{Timeout: web.Timeout}
	res, err := httpClient.Head(appsCatalogueURL)
	if err != nil {
		return false, err
	}

	lastModified := res.Header["Last-Modified"][0]
	parsed, err := time.Parse(time.RFC1123, lastModified)
	if err != nil {
		return false, err
	}
	info, err := os.Stat(config.APPS_JSON)
	if err != nil {
		if os.IsNotExist(err) {
			return false, nil
		}
		return false, err
	}

	localModifiedTime := info.ModTime().Unix()
	remoteModifiedTime := parsed.Unix()

	if localModifiedTime < remoteModifiedTime {
		return false, nil
	}

	return true, nil
}

func ReadAppsCatalogue() (AppsCatalogue, error) {
	apps := make(AppsCatalogue)

	appsFSIsLatest, err := appsCatalogueFSIsLatest()
	if err != nil {
		return nil, err
	}

	if !appsFSIsLatest {
		if err := readAppsCatalogueWeb(&apps); err != nil {
			return nil, err
		}
		return apps, nil
	}

	if err := readAppsCatalogueFS(&apps); err != nil {
		return nil, err
	}

	return apps, nil
}

func readAppsCatalogueFS(target interface{}) error {
	appsJSONFS, err := ioutil.ReadFile(config.APPS_JSON)
	if err != nil {
		return err
	}
	if err := json.Unmarshal(appsJSONFS, &target); err != nil {
		return err
	}
	return nil
}

func readAppsCatalogueWeb(target interface{}) error {
	if err := web.ReadJSON(appsCatalogueURL, &target); err != nil {
		return err
	}

	appsJSON, err := json.MarshalIndent(target, "", "    ")
	if err != nil {
		return err
	}

	if err := ioutil.WriteFile(config.APPS_JSON, appsJSON, 0644); err != nil {
		return err
	}

	return nil
}

func VersionsOfService(recipe, serviceName string) ([]string, error) {
	catl, err := ReadAppsCatalogue()
	if err != nil {
		return nil, err
	}

	app, ok := catl[recipe]
	if !ok {
		return nil, fmt.Errorf("recipe '%s' does not exist?", recipe)
	}

	versions := []string{}
	alreadySeen := make(map[string]bool)
	for version := range app.Versions {
		appVersion := app.Versions[version][serviceName].Tag
		if _, ok := alreadySeen[appVersion]; !ok {
			alreadySeen[appVersion] = true
			versions = append(versions, appVersion)
		}
	}

	return versions, nil
}