import { getFoldersInFolder } from "../helpers/fs.helpers";
import path from "path";
import { VersionLinkerAction, VersionUnlinkFolderAction } from "renderer/services/version-folder-linker.service";
import { BSVersion } from "shared/bs-version.interface";
import { LocalMapsManagerService } from "./additional-content/maps/local-maps-manager.service";
import { BSLocalVersionService } from "./bs-local-version.service";
import { FolderLinkerService, LinkOptions } from "./folder-linker.service";
import { allSettled } from "../../shared/helpers/promise.helpers";

export class VersionFolderLinkerService {
    private static instance: VersionFolderLinkerService;

    public static getInstance(): VersionFolderLinkerService {
        if (!VersionFolderLinkerService.instance) {
            VersionFolderLinkerService.instance = new VersionFolderLinkerService();
        }
        return VersionFolderLinkerService.instance;
    }

    private readonly localVersion: BSLocalVersionService;
    private readonly folderLinker: FolderLinkerService;

    private constructor() {
        this.localVersion = BSLocalVersionService.getInstance();
        this.folderLinker = FolderLinkerService.getInstance();
    }

    private specialFolderOption(relativeFolder: string, options: LinkOptions): LinkOptions {
        if (relativeFolder.includes(LocalMapsManagerService.CUSTOM_LEVELS_FOLDER)) {
            return { ...options, intermediateFolder: LocalMapsManagerService.SHARED_MAPS_FOLDER };
        }

        if (relativeFolder.includes("UserData")) {
            return { ...options, backup: true };
        }

        return options ?? {};
    }

    private async isOtherVersionHaveFolderLinked(relativeFolder: string, ignorePath: string): Promise<boolean> {
        const versions = await this.localVersion.getInstalledVersions();
        const versionPaths = await allSettled(versions.map(version => this.localVersion.getVersionPath(version)));

        for (const versionPath of versionPaths) {
            const folderPath = this.relativeToFullPath(versionPath, relativeFolder);
            if (folderPath === ignorePath) {
                continue;
            }
            if (await this.folderLinker.isFolderSymlink(folderPath)) {
                return true;
            }
        }

        return false;
    }

    private relativeToFullPath(parentPath: string, relativePath: string): string {
        return path.join(parentPath, relativePath);
    }

    public async linkVersionFolder(action: VersionLinkerAction): Promise<void> {
        action.options = this.specialFolderOption(action.relativeFolder, action.options);
        const versionPath = await this.localVersion.getVersionPath(action.version);
        const folderPath = this.relativeToFullPath(versionPath, action.relativeFolder);
        return this.folderLinker.linkFolder(folderPath, action.options)
    }

    public async unlinkVersionFolder(action: VersionUnlinkFolderAction): Promise<void> {
        action.options = this.specialFolderOption(action.relativeFolder, action.options);

        const versionPath = await this.localVersion.getVersionPath(action.version);
        const folderPath = this.relativeToFullPath(versionPath, action.relativeFolder);

        action.options.moveContents = !(await this.isOtherVersionHaveFolderLinked(action.relativeFolder, folderPath));

        return this.folderLinker.unlinkFolder(folderPath, action.options);
    }

    public doAction(action: VersionLinkerAction): Promise<void> {
        if (action.type === "link") {
            return this.linkVersionFolder(action);
        }
        return this.unlinkVersionFolder(action as VersionUnlinkFolderAction);
    }

    public async isFolderLinked(version: BSVersion, relativeFolder: string): Promise<boolean> {
        if (!version) {
            return Promise.reject("no version provided");
        }
        const versionPath = await this.localVersion.getVersionPath(version);
        const folderPath = this.relativeToFullPath(versionPath, relativeFolder);
        return this.folderLinker.isFolderSymlink(folderPath);
    }

    public async getLinkedFolders(version: BSVersion, options?: { relative?: boolean; ignoreSymlinkTargetError?: boolean }): Promise<string[]> {
        const versionPath = await this.localVersion.getVersionPath(version);
        const [rootFolders, beatSaberDataFolders] = await Promise.all([getFoldersInFolder(versionPath, { ignoreSymlinkTargetError: options?.ignoreSymlinkTargetError }), getFoldersInFolder(path.join(versionPath, "Beat Saber_Data"), { ignoreSymlinkTargetError: options?.ignoreSymlinkTargetError })]);

        const linkedFolders = await Promise.all(
            [...rootFolders, ...beatSaberDataFolders].map(async folder => {
                if (!(await this.folderLinker.isFolderSymlink(folder))) {
                    return null;
                }
                return folder;
            })
        );

        if (options?.relative) {
            return linkedFolders.filter(folder => folder).map(folder => path.relative(versionPath, folder));
        }

        return linkedFolders.filter(folder => folder);
    }

    public async relinkAllVersionsFolders(): Promise<void> {
        const versions = await this.localVersion.getInstalledVersions();

        for (const version of versions) {
            const linkedFolders = await this.getLinkedFolders(version, { relative: true, ignoreSymlinkTargetError: true });
            const actions = linkedFolders.map(folder => ({ type: "link", version, relativeFolder: folder } as VersionLinkerAction));
            await Promise.all(actions.map(action => this.doAction(action)));
        }
    }
}