package curseforge

import (
	"errors"
	"fmt"
	"regexp"
	"strconv"

	"github.com/comp500/packwiz/core"
	"github.com/mitchellh/mapstructure"
	"github.com/skratchdot/open-golang/open"
	"github.com/urfave/cli"
)

func init() {
	core.Commands = append(core.Commands, cli.Command{
		Name:  "curseforge",
		Usage: "Manage curseforge-based mods",
		Subcommands: []cli.Command{{
			Name:    "install",
			Usage:   "Install a mod from a curseforge URL, slug or ID",
			Aliases: []string{"add", "get"},
			Action: func(c *cli.Context) error {
				return cmdInstall(core.FlagsFromContext(c), c.Args().Get(0), c.Args().Tail())
			},
		}, {
			Name:  "import",
			Usage: "Import an installed curseforge modpack",
			Action: func(c *cli.Context) error {
				return cmdImport(core.FlagsFromContext(c), c.Args().Get(0))
			},
		}, {
			Name: "open",
			// TODO: change semantics to "project" rather than "mod", as this supports texture packs and misc content as well
			Usage:   "Open the project page for a curseforge mod in your browser",
			Aliases: []string{"doc"},
			Action: func(c *cli.Context) error {
				return cmdDoc(core.FlagsFromContext(c), c.Args().Get(0))
			},
		}},
	})
	core.Updaters["curseforge"] = cfUpdater{}
}

var fileIDRegexes = [...]*regexp.Regexp{
	regexp.MustCompile("^https?:\\/\\/minecraft\\.curseforge\\.com\\/projects\\/(.+)\\/files\\/(\\d+)$"),
	regexp.MustCompile("^https?:\\/\\/(?:www\\.)?curseforge\\.com\\/minecraft\\/mc-mods\\/(.+)\\/download\\/(\\d+)$"),
}

func getFileIDsFromString(mod string) (bool, int, int, error) {
	for _, v := range fileIDRegexes {
		matches := v.FindStringSubmatch(mod)
		if matches != nil && len(matches) == 3 {
			modID, err := modIDFromSlug(matches[1])
			fileID, err := strconv.Atoi(matches[2])
			if err != nil {
				return true, 0, 0, err
			}
			return true, modID, fileID, nil
		}
	}
	return false, 0, 0, nil
}

var modSlugRegexes = [...]*regexp.Regexp{
	regexp.MustCompile("^https?:\\/\\/minecraft\\.curseforge\\.com\\/projects\\/([^\\/]+)$"),
	regexp.MustCompile("^https?:\\/\\/(?:www\\.)?curseforge\\.com\\/minecraft\\/mc-mods\\/([^\\/]+)$"),
	// Exact slug matcher
	regexp.MustCompile("^[a-z][\\da-z\\-]{0,127}$"),
}

func getModIDFromString(mod string) (bool, int, error) {
	// Check if it's just a number first
	modID, err := strconv.Atoi(mod)
	if err == nil && modID > 0 {
		return true, modID, nil
	}

	for _, v := range modSlugRegexes {
		matches := v.FindStringSubmatch(mod)
		if matches != nil {
			var slug string
			if len(matches) == 2 {
				slug = matches[1]
			} else if len(matches) == 1 {
				slug = matches[0]
			} else {
				continue
			}
			modID, err := modIDFromSlug(slug)
			if err != nil {
				return true, 0, err
			}
			return true, modID, nil
		}
	}
	return false, 0, nil
}

func createModFile(flags core.Flags, modInfo modInfo, fileInfo modFileInfo, index *core.Index) error {
	updateMap := make(map[string]map[string]interface{})
	var err error

	updateMap["curseforge"], err = cfUpdateData{
		ProjectID: modInfo.ID,
		FileID:    fileInfo.ID,
		// TODO: determine update channel
		ReleaseChannel: "beta",
	}.ToMap()
	if err != nil {
		return err
	}

	modMeta := core.Mod{
		Name:     modInfo.Name,
		FileName: fileInfo.FileName,
		Side:     core.UniversalSide,
		Download: core.ModDownload{
			URL: fileInfo.DownloadURL,
			// TODO: murmur2 hashing may be unstable in curse api, calculate the hash manually?
			// TODO: check if the hash is invalid (e.g. 0)
			HashFormat: "murmur2",
			Hash:       strconv.Itoa(fileInfo.Fingerprint),
		},
		Update: updateMap,
	}
	path := modMeta.SetMetaName(modInfo.Slug, flags)

	// If the file already exists, this will overwrite it!!!
	// TODO: Should this be improved?
	// Current strategy is to go ahead and do stuff without asking, with the assumption that you are using
	// VCS anyway.

	format, hash, err := modMeta.Write()
	if err != nil {
		return err
	}

	// TODO: send written data directly to index, instead of write+read?
	return index.RefreshFileWithHash(path, format, hash, true)
}

func cmdDoc(flags core.Flags, mod string) error {
	if len(mod) == 0 {
		return cli.NewExitError("You must specify a mod.", 1)
	}

	fmt.Println("Loading modpack...")
	pack, err := core.LoadPack(flags)
	if err != nil {
		return cli.NewExitError(err, 1)
	}
	index, err := pack.LoadIndex()
	if err != nil {
		return cli.NewExitError(err, 1)
	}
	resolvedMod, ok := index.FindMod(mod)
	if !ok {
		// TODO: should this auto-refresh???????
		return cli.NewExitError("You don't have this mod installed.", 1)
	}
	modData, err := core.LoadMod(resolvedMod)
	if err != nil {
		return cli.NewExitError(err, 1)
	}
	updateData, ok := modData.GetParsedUpdateData("curseforge")
	if !ok {
		return cli.NewExitError("This mod doesn't seem to be a curseforge mod!", 1)
	}
	cfUpdateData := updateData.(cfUpdateData)
	fmt.Println("Opening browser...")
	url := "https://minecraft.curseforge.com/projects/" + strconv.Itoa(cfUpdateData.ProjectID)
	err = open.Start(url)
	if err != nil {
		fmt.Println("Opening page failed, direct link:")
		fmt.Println(url)
	}

	return nil
}

type cfUpdateData struct {
	ProjectID      int    `mapstructure:"project-id"`
	FileID         int    `mapstructure:"file-id"`
	ReleaseChannel string `mapstructure:"release-channel"`
}

func (u cfUpdateData) ToMap() (map[string]interface{}, error) {
	newMap := make(map[string]interface{})
	err := mapstructure.Decode(u, &newMap)
	return newMap, err
}

type cfUpdater struct{}

func (u cfUpdater) ParseUpdate(updateUnparsed map[string]interface{}) (interface{}, error) {
	var updateData cfUpdateData
	err := mapstructure.Decode(updateUnparsed, &updateData)
	return updateData, err
}

type cachedStateStore struct {
	modInfo
	fileInfo modFileInfo
}

func (u cfUpdater) CheckUpdate(mods []core.Mod, mcVersion string) ([]core.UpdateCheck, error) {
	results := make([]core.UpdateCheck, len(mods))

	// TODO: make this batched
	for i, v := range mods {
		projectRaw, ok := v.GetParsedUpdateData("curseforge")
		if !ok {
			results[i] = core.UpdateCheck{Error: errors.New("couldn't parse mod data")}
			continue
		}
		project := projectRaw.(cfUpdateData)
		modInfoData, err := getModInfo(project.ProjectID)
		if err != nil {
			results[i] = core.UpdateCheck{Error: err}
			continue
		}

		updateAvailable := false
		fileID := project.FileID
		fileInfoObtained := false
		var fileInfoData modFileInfo

		for _, file := range modInfoData.GameVersionLatestFiles {
			// TODO: change to timestamp-based comparison??
			// TODO: manage alpha/beta/release correctly, check update channel?
			// Choose "newest" version by largest ID
			if file.GameVersion == mcVersion && file.ID > fileID {
				updateAvailable = true
				fileID = file.ID
			}
		}

		if !updateAvailable {
			results[i] = core.UpdateCheck{UpdateAvailable: false}
			continue
		}

		// The API also provides some files inline, because that's efficient!
		for _, file := range modInfoData.LatestFiles {
			if file.ID == fileID {
				fileInfoObtained = true
				fileInfoData = file
			}
		}

		if !fileInfoObtained {
			fileInfoData, err = getFileInfo(project.ProjectID, fileID)
			if err != nil {
				results[i] = core.UpdateCheck{Error: err}
				continue
			}
		}

		results[i] = core.UpdateCheck{
			UpdateAvailable: true,
			UpdateString:    v.FileName + " -> " + fileInfoData.FileName,
			CachedState:     cachedStateStore{modInfoData, fileInfoData},
		}
	}
	return results, nil
}

func (u cfUpdater) DoUpdate(mods []*core.Mod, cachedState []interface{}) error {
	// "Do" isn't really that accurate, more like "Apply", because all the work is done in CheckUpdate!
	for i, v := range mods {
		modState := cachedState[i].(cachedStateStore)

		v.FileName = modState.fileInfo.FileName
		v.Name = modState.Name
		v.Download = core.ModDownload{
			URL: modState.fileInfo.DownloadURL,
			// TODO: murmur2 hashing may be unstable in curse api, calculate the hash manually?
			// TODO: check if the hash is invalid (e.g. 0)
			HashFormat: "murmur2",
			Hash:       strconv.Itoa(modState.fileInfo.Fingerprint),
		}

		v.Update["curseforge"]["ProjectID"] = modState.ID
		v.Update["curseforge"]["FileID"] = modState.fileInfo.ID
	}

	return nil
}