package version_manifest

import (
	"encoding/json"
	"fmt"
	"time"
)

// VersionManifestUrl is a URL to a version manifest JSON file of version 2.
const VersionManifestUrl = "https://launchermeta.mojang.com/mc/game/version_manifest_v2.json"

// VersionType is telling if it is a stable release or an intermedialry snapshot.
type VersionType string

const (
	// VersionTypeSnapshot is an unstable intermediary version of a game.
	VersionTypeSnapshot VersionType = "snapshot"
	// VersionTypeRelease is a stable release version of a game.
	VersionTypeRelease VersionType = "release"
)

// Version holds an information about a particular version.
type Version struct {
	Id          string      `json:"id"`
	Type        VersionType `json:"type"`
	Url         string      `json:"url"`
	Time        time.Time   `json:"time"`
	ReleaseTime time.Time   `json:"releaseTime"`
	Sha1        string      `json:"sha1"`
}

// VersionManifest holds an array of all game versions, also a latest metadata
// that holds the latest release and snapshot.
type VersionManifest struct {
	Latest struct {
		Release  string `json:"release"`
		Snapshot string `json:"snapshot"`
	} `json:"latest"`
	Versions []Version `json:"versions"`
}

// New returns a new VersionManifest that holds info on every
// known Minecraft version.
func New(data []byte) (*VersionManifest, error) {
	vm := &VersionManifest{}
	if err := json.Unmarshal(data, vm); err != nil {
		return nil, err
	}
	return vm, nil
}

// GetLatest returns a latest release or snapshot depending on a type provided.
func (vm *VersionManifest) GetLatest(typ VersionType) (Version, error) {
	var version string
	switch typ {
	case VersionTypeSnapshot:
		version = vm.Latest.Snapshot
	case VersionTypeRelease:
		version = vm.Latest.Release
	default:
		return Version{}, fmt.Errorf("version type %s doesn't exist", typ)
	}
	return vm.Get(version)
}

// Get returns a specific version of Minecraft.
func (vm *VersionManifest) Get(version string) (Version, error) {
	for _, v := range vm.Versions {
		if v.Id == version {
			return v, nil
		}
	}
	return Version{}, fmt.Errorf("version %s not found", version)
}