Server/project/src/loaders/PreAkiModLoader.ts

import { execSync } from "child_process";
import os from "os";
import path from "path";
import semver from "semver";
import { DependencyContainer, inject, injectable } from "tsyringe";
import { ConfigTypes } from "../models/enums/ConfigTypes";
import { IPreAkiLoadMod } from "../models/external/IPreAkiLoadMod";
import { IPreAkiLoadModAsync } from "../models/external/IPreAkiLoadModAsync";
import { ICoreConfig } from "../models/spt/config/ICoreConfig";
import { IModLoader } from "../models/spt/mod/IModLoader";
import { IPackageJsonData } from "../models/spt/mod/IPackageJsonData";
import { ILogger } from "../models/spt/utils/ILogger";
import { ConfigServer } from "../servers/ConfigServer";
import { LocalisationService } from "../services/LocalisationService";
import { ModCompilerService } from "../services/ModCompilerService";
import { JsonUtil } from "../utils/JsonUtil";
import { VFS } from "../utils/VFS";
import { BundleLoader } from "./BundleLoader";
import { ModTypeCheck } from "./ModTypeCheck";

@injectable()
export class PreAkiModLoader implements IModLoader
{
    protected static container: DependencyContainer;

    protected readonly basepath = "user/mods/";
    protected readonly modOrderPath = "user/mods/order.json";
    protected order: Record<string, number> = {};
    protected imported: Record<string, IPackageJsonData> = {};
    protected akiConfig: ICoreConfig;
    protected serverDependencies: Record<string, string>;
    protected skippedMods: string[] = [];

    constructor(
        @inject("WinstonLogger") protected logger: ILogger,
        @inject("VFS") protected vfs: VFS,
        @inject("JsonUtil") protected jsonUtil: JsonUtil,
        @inject("ModCompilerService") protected modCompilerService: ModCompilerService,
        @inject("BundleLoader") protected bundleLoader: BundleLoader,
        @inject("LocalisationService") protected localisationService: LocalisationService,
        @inject("ConfigServer") protected configServer: ConfigServer,
        @inject("ModTypeCheck") protected modTypeCheck: ModTypeCheck
    )
    {
        this.akiConfig = this.configServer.getConfig<ICoreConfig>(ConfigTypes.CORE);

        const packageJsonPath: string = path.join(__dirname, "../../package.json");
        this.serverDependencies = JSON.parse(this.vfs.readFile(packageJsonPath)).dependencies;
    }

    public async load(container: DependencyContainer): Promise<void>
    {
        if (globalThis.G_MODS_ENABLED)
        {
            PreAkiModLoader.container = container;
            await this.importMods();
            await this.executeMods(container);
        }
    }

    /**
     * Returns a list of mods with preserved load order
     * @returns Array of mod names in load order
     */
    public getImportedModsNames(): string[]
    {
        return Object.keys(this.imported);
    }

    public getImportedModDetails(): Record<string, IPackageJsonData>
    {
        return this.imported;
    }

    public getModPath(mod: string): string
    {
        return `${this.basepath}${mod}/`;
    }

    protected async importMods(): Promise<void>
    {
        if (!this.vfs.exists(this.basepath))
        {
            // no mods folder found
            this.logger.info(this.localisationService.getText("modloader-user_mod_folder_missing"));
            this.vfs.createDir(this.basepath);
            return;
        }

        let mods: string[] = this.vfs.getDirs(this.basepath);
        
        this.logger.info(this.localisationService.getText("modloader-loading_mods", mods.length));

        // Mod order
        if (!this.vfs.exists(this.modOrderPath)) 
        {
            this.logger.info(this.localisationService.getText("modloader-mod_order_missing"));

            // Write file with empty order array to disk
            this.vfs.writeFile(this.modOrderPath, this.jsonUtil.serializeAdvanced({order: []}, null, 4));
        }
        else 
        {
            const modOrder = this.vfs.readFile(this.modOrderPath, { encoding: "utf8" });
            try 
            {
                this.jsonUtil.deserialize<any>(modOrder).order.forEach((mod: string, index: number) => 
                {
                    this.order[mod] = index;
                });
            }
            catch (error) 
            {
                this.logger.error(this.localisationService.getText("modloader-mod_order_error"));
            }
        }

        // Used to check all errors before stopping the load execution
        let errorsFound = false;

        // Validate and remove broken mods from mod list
        const brokenMods: string[] = this.getBrokenMods(mods);
        mods = mods.filter( ( mod ) => !brokenMods.includes( mod ) );

        const modPackageData = this.getModsPackageData(mods);
        this.checkForDuplicateMods(modPackageData);
        for (const modFolderName in modPackageData)
        {
            const modToValidate = modPackageData[modFolderName];

            // if the mod has library dependencies check if these dependencies are bundled in the server, if not install them
            if (modToValidate.dependencies && Object.keys(modToValidate.dependencies).length > 0 && !this.vfs.exists(`${this.basepath}${modFolderName}/node_modules`)) 
            {
                this.autoInstallDependencies(`${this.basepath}${modFolderName}`, modToValidate);
            }

            // Returns if any mod dependency is not satisfied
            if (!this.areModDependenciesFulfilled(modToValidate, modPackageData))
            {
                errorsFound = true;
            }

            // Returns if at least two incompatible mods are found
            if (!this.isModCompatible(modToValidate, modPackageData))
            {
                errorsFound = true;
            }

            // Returns if mod isnt compatible with this verison of aki
            if (!this.isModCombatibleWithAki(modToValidate))
            {
                errorsFound = true;
            }
        }

        if (errorsFound)
        {
            this.logger.error(this.localisationService.getText("modloader-no_mods_loaded"));
            return;
        }

        // sort mod order
        const missingFromOrderJSON = {};
        const sortedMods = mods.sort((prev, next) => this.sortMods(prev, next, missingFromOrderJSON));

        // log the missing mods from order.json
        Object.keys(missingFromOrderJSON).forEach((missingMod) => (this.logger.debug(this.localisationService.getText("modloader-mod_order_missing_from_json", missingMod))));

        // add mods
        for (const mod of sortedMods)
        {
            await this.addMod(mod);
        }
    }

    protected sortMods(prev: string, next: string, missingFromOrderJSON: Record<string, boolean>): number
    {
        const previndex = this.order[prev];
        const nextindex = this.order[next];
        
        // mod is not on the list, move the mod to last
        if (previndex === undefined) 
        {
            missingFromOrderJSON[prev] = true;

            return 1;
        }
        else if (nextindex === undefined) 
        {
            missingFromOrderJSON[next] = true;

            return -1;
        }

        return previndex - nextindex;
    }

    /**
     * Check for duplicate mods loaded, show error if any
     * @param modPackageData Dictionary of mod package.json data
     */
    protected checkForDuplicateMods(modPackageData: Record<string, IPackageJsonData>): void
    {
        const modNames = [];
        for (const modKey in modPackageData)
        {
            const mod = modPackageData[modKey];
            modNames.push(`${mod.author}-${mod.name}`);
        }
        const dupes = this.getDuplicates(modNames);
        if (dupes?.length > 0)
        {
            this.logger.error(this.localisationService.getText("modloader-x_duplicates_found", dupes.join(",")));
        }
    }

    /**
     * Check for and return duplicate strings inside an array
     * @param stringArray Array to check for duplicates
     * @returns string array of duplicates, empty if none found
     */
    protected getDuplicates(stringArray: string[]): string[]
    {
        return stringArray.filter((s => v => s.has(v) || !s.add(v))(new Set));
    }

    /**
     * Get an array of mods with errors that prevent them from working with SPT
     * @param mods mods to validate
     * @returns Mod names as array
     */
    protected getBrokenMods(mods: string[]): string[]
    {
        const brokenMods: string[] = [];
        for (const mod of mods)
        {
            if (!this.validMod(mod))
            {
                brokenMods.push(mod);
            }
        }

        return brokenMods;
    }

    /**
     * Get packageJson data for mods
     * @param mods mods to get packageJson for
     * @returns dictionary <modName - package.json>
     */
    protected getModsPackageData(mods: string[]): Record<string, IPackageJsonData>
    {
        const loadedMods: Record<string, IPackageJsonData> = {};
        for (const mod of mods)
        {
            loadedMods[mod] = this.jsonUtil.deserialize(this.vfs.readFile(`${this.getModPath(mod)}/package.json`));
        }

        return loadedMods;
    }


    protected isModCombatibleWithAki(mod: IPackageJsonData): boolean
    {
        const akiVersion = this.akiConfig.akiVersion;
        const modName = `${mod.author}-${mod.name}`;

        // Error and prevent loading If no akiVersion property exists
        if (!mod.akiVersion)
        {
            this.logger.error(this.localisationService.getText("modloader-missing_akiversion_field", modName));
            return false;
        }

        // Error and prevent loading if akiVersion property is not a valid semver string
        if (!(semver.valid(mod.akiVersion) || semver.validRange(mod.akiVersion)))
        {
            this.logger.error(this.localisationService.getText("modloader-invalid_akiversion_field", modName));
            return false;
        }

        // Warn and allow loading if semver is not satisfied
        if (!semver.satisfies(akiVersion, mod.akiVersion))
        {
            this.logger.warning(this.localisationService.getText("modloader-outdated_akiversion_field", modName));
            return true;
        }

        return true;
    }

    protected async executeMods(container: DependencyContainer): Promise<void>
    {
        // sort mods load order
        const source = this.sortModsLoadOrder();

        // import mod classes
        for (const mod of source)
        {

            if ("main" in this.imported[mod])
            {
                const filepath = `${this.getModPath(mod)}${this.imported[mod].main}`;
                // import class
                const modFilePath = `${process.cwd()}/${filepath}`;

                // eslint-disable-next-line @typescript-eslint/no-var-requires
                const requiredMod = require(modFilePath);

                if (!this.modTypeCheck.isPostV3Compatible(requiredMod.mod))
                {
                    this.logger.error(this.localisationService.getText("modloader-mod_incompatible", mod));
                    delete this.imported[mod];
                    return;
                }

                if (this.modTypeCheck.isPreAkiLoadAsync(requiredMod.mod))
                {
                    try 
                    {
                        await (requiredMod.mod as IPreAkiLoadModAsync).preAkiLoadAsync(container);
                        globalThis[mod] = requiredMod;
                    }
                    catch (err) 
                    {
                        this.logger.error(this.localisationService.getText("modloader-async_mod_error", `${err?.message ?? ""}\n${err.stack ?? ""}`));
                    }
                }

                if (this.modTypeCheck.isPreAkiLoad(requiredMod.mod))
                {
                    (requiredMod.mod as IPreAkiLoadMod).preAkiLoad(container);
                    globalThis[mod] = requiredMod;
                }
            }
        }
    }

    public sortModsLoadOrder(): string[]
    {
        // if loadorder.json exists: load it, otherwise generate load order
        if (this.vfs.exists(`${this.basepath}loadorder.json`))
        {
            return this.jsonUtil.deserialize(this.vfs.readFile(`${this.basepath}loadorder.json`));
        }
        else
        {
            return Object.keys(this.getLoadOrder(this.imported));
        }
    }

    protected async addMod(mod: string): Promise<void>
    {
        const modPath = this.getModPath(mod);
        const packageData = this.jsonUtil.deserialize<IPackageJsonData>(this.vfs.readFile(`${modPath}/package.json`));

        if (this.skippedMods.includes(packageData.name))
        {
            this.logger.warning(this.localisationService.getText("modloader-skipped_mod", {name: packageData.name, author: packageData.author}));
            return;
        }

        const isBundleMod = packageData.isBundleMod ?? false;

        if (isBundleMod)
        {
            this.bundleLoader.addBundles(modPath);
        }

        const typeScriptFiles = this.vfs.getFilesOfType(`${modPath}src`, ".ts");

        if (typeScriptFiles.length > 0)
        {
            if (globalThis.G_MODS_TRANSPILE_TS)
            {
                // compile ts into js if ts files exist and globalThis.G_MODS_TRANSPILE_TS is set to true
                await this.modCompilerService.compileMod(mod, modPath, typeScriptFiles);
            }
            else
            {
                // rename the mod entry point to .ts if it's set to .js because G_MODS_TRANSPILE_TS is set to false
                packageData.main = (packageData.main as string).replace(".js", ".ts");
            }
        }

        // add mod to imported list
        this.imported[mod] = {...packageData, dependencies: packageData.modDependencies};
        this.logger.info(this.localisationService.getText("modloader-loaded_mod", {name: packageData.name, version: packageData.version, author: packageData.author}));
    }

    protected autoInstallDependencies(modPath: string, pkg: IPackageJsonData): void
    {
        const dependenciesToInstall: [string, string][] = Object.entries(pkg.dependencies);

        let depIdx = 0;
        for (const [depName, depVersion] of dependenciesToInstall)
        {
            // currently not checking for version mismatches, but we could check it, just don't know what we would do afterwards, some options would be:
            // 1 - throw an error
            // 2 - use the server's version (which is what's currently happening by not checking the version)
            // 3 - use the mod's version (don't know the reprecursions this would have, or if it would even work)

            // if a dependency from the mod exists in the server dependencies we can safely remove it from the list of dependencies to install since it already comes bundled in the server.
            if (this.serverDependencies[depName])
            {
                dependenciesToInstall.splice(depIdx, 1);
            }
            depIdx++;
        }

        //if the mod has no extra dependencies return as there's nothing that needs to be done.
        if (dependenciesToInstall.length === 0)
        {
            return;
        }

        //if this feature flag is set to false, we warn the user he has a mod that requires extra dependencies and might not work, point them in the right direction on how to enable this feature.
        if (!this.akiConfig.features.autoInstallModDependencies)
        {
            this.logger.warning(this.localisationService.getText("modloader-installing_external_dependencies_disabled", {
                name: pkg.name,
                author: pkg.author,
                configPath: path.join(globalThis.G_RELEASE_CONFIGURATION ? "Aki_Data/Server/configs" : "assets/configs", "core.json"),
                configOption: "autoInstallModDependencies"
            }));

            this.skippedMods.push(pkg.name);
            return;
        }

        //temporarily rename package.json because otherwise npm, pnpm and any other package manager will forcefully download all packages in dependencies without any way of disabling this behavior
        this.vfs.rename(`${modPath}/package.json`, `${modPath}/package.json.bak`);
        this.vfs.writeFile(`${modPath}/package.json`, "{}");

        this.logger.info(this.localisationService.getText("modloader-installing_external_dependencies", {name: pkg.name, author: pkg.author}));

        const pnpmPath = path.join(process.cwd(), (globalThis.G_RELEASE_CONFIGURATION ? "Aki_Data/Server/@pnpm/exe" : "node_modules/@pnpm/exe"), (os.platform() === "win32" ? "pnpm.exe" : "pnpm"));
        let command: string = `${pnpmPath} install `;
        command += dependenciesToInstall.map(([depName, depVersion]) => `${depName}@${depVersion}`).join(" ");
        execSync(command, { cwd: modPath });

        // delete the new blank package.json then rename the backup back to the original name
        this.vfs.removeFile(`${modPath}/package.json`);
        this.vfs.rename(`${modPath}/package.json.bak`, `${modPath}/package.json`);
    }

    protected areModDependenciesFulfilled(pkg: IPackageJsonData, loadedMods: Record<string, IPackageJsonData>): boolean
    {
        if (!pkg.modDependencies)
        {
            return true;
        }

        const modName = `${pkg.author}-${pkg.name}`;

        for (const [modDependency, requiredVersion ] of Object.entries(pkg.modDependencies))
        {
            // Raise dependency version incompatible if the dependency is not found in the mod list
            if (!(modDependency in loadedMods))
            {
                this.logger.error(this.localisationService.getText("modloader-missing_dependency", {mod: modName, modDependency: modDependency}));
                return false;
            }

            if (!semver.satisfies(loadedMods[modDependency].version, requiredVersion))
            {
                this.logger.error(this.localisationService.getText("modloader-outdated_dependency", {mod: modName, modDependency: modDependency, currentVersion: loadedMods[modDependency].version, requiredVersion: requiredVersion}));
                return false;
            }
        }

        return true;
    }

    protected isModCompatible(mod: IPackageJsonData, loadedMods: Record<string, IPackageJsonData>): boolean
    {
        const incompatbileModsList = mod.incompatibilities;
        if (!incompatbileModsList)
        {
            return true;
        }

        for (const incompatibleModName of incompatbileModsList)
        {
            // Raise dependency version incompatible if any incompatible mod is found
            if (incompatibleModName in loadedMods)
            {
                this.logger.error(this.localisationService.getText("modloader-incompatible_mod_found", {author: mod.author, modName: mod.name, incompatibleModName: incompatibleModName}));
                return false;
            }
        }

        return true;
    }

    /**
     * Validate a mod passes a number of checks
     * @param modName name of mod in /mods/ to validate
     * @returns true if valid
     */
    protected validMod(modName: string): boolean
    {
        const modPath = this.getModPath(modName);

        const modIsCalledBepinEx = modName.toLowerCase() === "bepinex";
        const modIsCalledUser = modName.toLowerCase() === "user";
        const modIsCalledSrc = modName.toLowerCase() === "src";
        const modIsCalledDb = modName.toLowerCase() === "db";
        const hasBepinExFolderStructure = this.vfs.exists(`${modPath}/plugins`);
        const containsDll = this.vfs.getFiles(`${modPath}`).find(x => x.includes(".dll"));

        if (modIsCalledSrc || modIsCalledDb || modIsCalledUser)
        {
            this.logger.error(this.localisationService.getText("modloader-not_correct_mod_folder", modName));
            return false;
        }

        if (modIsCalledBepinEx || hasBepinExFolderStructure || containsDll)
        {
            this.logger.error(this.localisationService.getText("modloader-is_client_mod", modName));
            return false;
        }

        // Check if config exists
        if (!this.vfs.exists(`${modPath}/package.json`))
        {
            this.logger.error(this.localisationService.getText("modloader-missing_package_json", modName));
            return false;
        }

        // Validate mod
        const config = this.jsonUtil.deserialize<IPackageJsonData>(this.vfs.readFile(`${modPath}/package.json`));
        const checks = ["name", "author", "version", "license"];
        let issue = false;

        for (const check of checks)
        {
            if (!(check in config))
            {
                this.logger.error(this.localisationService.getText("modloader-missing_package_json_property", {modName: modName, prop: check}));
                issue = true;
            }
        }

        if (!semver.valid(config.version))
        {
            this.logger.error(this.localisationService.getText("modloader-invalid_version_property", modName));
            issue = true;
        }

        if ("main" in config)
        {
            if (config.main.split(".").pop() !== "js") // expects js file as entry
            {
                this.logger.error(this.localisationService.getText("modloader-main_property_not_js", modName));
                issue = true;
            }


            if (!this.vfs.exists(`${modPath}/${config.main}`))
            {

                // If TS file exists with same name, dont perform check as we'll generate JS from TS file
                const tsFileName = config.main.replace(".js", ".ts");
                const tsFileExists = this.vfs.exists(`${modPath}/${tsFileName}`);

                if (!tsFileExists)
                {
                    this.logger.error(this.localisationService.getText("modloader-main_property_points_to_nothing", modName));
                    issue = true;
                }
            }
        }

        if (config.incompatibilities && !Array.isArray(config.incompatibilities))
        {
            this.logger.error(this.localisationService.getText("modloader-incompatibilities_not_string_array", modName));
            issue = true;
        }

        return !issue;
    }

    protected getLoadOrderRecursive(mod: string, result: Record<string, string>, visited: Record<string, string>): void
    {
        // validate package
        if (mod in result)
        {
            return;
        }

        if (mod in visited)
        {
            // front: white, back: red
            this.logger.error(this.localisationService.getText("modloader-cyclic_dependency"));

            // additional info
            this.logger.debug(this.localisationService.getText("modloader-checking_mod", mod));
            this.logger.debug(`${this.localisationService.getText("modloader-checked")}:`);
            this.logger.debug(result);
            this.logger.debug(`${this.localisationService.getText("modloader-visited")}:`);
            this.logger.debug(visited);

            // wait for input
            process.exit(1);
        }

        // check dependencies
        const config = this.imported[mod];

        if (typeof config === "undefined")
        {
            this.logger.error(this.localisationService.getText("modloader-missing_dependency"));
            throw new Error(this.localisationService.getText("modloader-error_parsing_mod_load_order"));
        }

        const dependencies: Record<string, string> = config.dependencies || {};

        visited[mod] = config.version;

        for (const dependency in dependencies)
        {
            this.getLoadOrderRecursive(dependency, result, visited);
        }

        delete visited[mod];

        // fully checked package
        result[mod] = config.version;
    }

    protected getLoadOrder(mods: Record<string, IPackageJsonData>): Record<string, string>
    {
        const result: Record<string, string> = {};
        const visited: Record<string, string> = {};

        for (const mod in mods)
        {
            if (mods[mod][0] in result)
            {
                continue;
            }

            this.getLoadOrderRecursive(mod, result, visited);
        }

        return result;
    }

    public getContainer(): DependencyContainer
    {
        if (PreAkiModLoader.container)
        {
            return PreAkiModLoader.container;
        }
        else
        {
            throw new Error(this.localisationService.getText("modloader-dependency_container_not_initalized"));
        }
    }
}