const gulp = require('gulp');
const fs = require('fs-extra');
const path = require('path');
const chalk = require('chalk');
const stringify = require('json-stringify-pretty-compact');
const typescript = require('typescript');

const ts = require('gulp-typescript');

const argv = require('yargs').argv;

function getManifest() {
    const json = {};

    if (fs.existsSync('src')) {
        json.root = 'src';
    } else {
        json.root = 'dist';
    }

    const modulePath = path.join(json.root, 'module.json');

    if (fs.existsSync(modulePath)) {
        json.file = fs.readJSONSync(modulePath);
        json.name = 'module.json';
    } else {
        return;
    }

    return json;
}

/**
 * TypeScript transformers
 * @returns {typescript.TransformerFactory<typescript.SourceFile>}
 */
function createTransformer() {
    /**
     * @param {typescript.Node} node
     */
    function shouldMutateModuleSpecifier(node) {
        if (!typescript.isImportDeclaration(node) && !typescript.isExportDeclaration(node)) return false;
        if (node.moduleSpecifier === undefined) return false;
        if (!typescript.isStringLiteral(node.moduleSpecifier)) return false;
        if (!node.moduleSpecifier.text.startsWith('./') && !node.moduleSpecifier.text.startsWith('../')) return false;
        if (path.extname(node.moduleSpecifier.text) !== '') return false;
        return true;
    }

    /**
     * Transforms import/export declarations to append `.js` extension
     * @param {typescript.TransformationContext} context
     */
    function importTransformer(context) {
        return (node) => {
            /**
             * @param {typescript.Node} node
             */
            function visitor(node) {
                if (shouldMutateModuleSpecifier(node)) {
                    if (typescript.isImportDeclaration(node)) {
                        const newModuleSpecifier = typescript.createLiteral(`${node.moduleSpecifier.text}.js`);
                        return typescript.updateImportDeclaration(
                            node,
                            node.decorators,
                            node.modifiers,
                            node.importClause,
                            newModuleSpecifier,
                        );
                    } else if (typescript.isExportDeclaration(node)) {
                        const newModuleSpecifier = typescript.createLiteral(`${node.moduleSpecifier.text}.js`);
                        return typescript.updateExportDeclaration(
                            node,
                            node.decorators,
                            node.modifiers,
                            node.exportClause,
                            newModuleSpecifier,
                        );
                    }
                }
                return typescript.visitEachChild(node, visitor, context);
            }

            return typescript.visitNode(node, visitor);
        };
    }

    return importTransformer;
}

const tsConfig = ts.createProject('tsconfig.json', {
    getCustomTransformers: (_program) => ({
        after: [createTransformer()],
    }),
});

/********************/
/*		BUILD		*/
/********************/

/**
 * Build TypeScript
 */
function buildTS() {
    return gulp.src('src/**/*.ts').pipe(tsConfig()).pipe(gulp.dest('dist'));
}

/**
 * Copy static files
 */
async function copyFiles() {
    const statics = ['lang', 'module.json'];
    try {
        for (const file of statics) {
            if (fs.existsSync(path.join('src', file))) {
                await fs.copy(path.join('src', file), path.join('dist', file));
            }
        }
        return Promise.resolve();
    } catch (err) {
        Promise.reject(err);
    }
}

/**
 * Watch for changes for each build step
 */
function buildWatch() {
    gulp.watch('src/**/*.ts', { ignoreInitial: false }, buildTS);
    gulp.watch(
        ['src/fonts', 'src/lang', 'src/templates', 'src/*.json', 'src/packs'],
        { ignoreInitial: false },
        copyFiles,
    );
}

/********************/
/*		CLEAN		*/
/********************/

/**
 * Remove built files from `dist` folder
 * while ignoring source files
 */
async function clean() {
    const name = path.basename(path.resolve('.'));
    const files = [];

    // If the project uses TypeScript
    if (fs.existsSync(path.join('src', 'module', `${name}.ts`))) {
        files.push('lang', 'module', `${name}.js`, 'module.json');
    }

    console.log(' ', chalk.yellow('Files to clean:'));
    console.log('   ', chalk.blueBright(files.join('\n    ')));

    // Attempt to remove the files
    try {
        for (const filePath of files) {
            await fs.remove(path.join('dist', filePath));
        }
        return Promise.resolve();
    } catch (err) {
        Promise.reject(err);
    }
}

/********************/
/*		LINK		*/
/********************/

/**
 * Link build to User Data folder
 */
async function linkUserData() {
    const name = path.basename(path.resolve('.'));
    const config = fs.readJSONSync('foundryconfig.json');

    let destDir;
    try {
        if (
            fs.existsSync(path.resolve('.', 'dist', 'module.json')) ||
            fs.existsSync(path.resolve('.', 'src', 'module.json'))
        ) {
            destDir = 'modules';
        } else {
            throw Error(`Could not find ${chalk.blueBright('module.json')}`);
        }

        let linkDir;
        if (config.dataPath) {
            if (!fs.existsSync(path.join(config.dataPath, 'Data')))
                throw Error('User Data path invalid, no Data directory found');

            linkDir = path.join(config.dataPath, 'Data', destDir, name);
        } else {
            throw Error('No User Data path defined in foundryconfig.json');
        }

        if (argv.clean || argv.c) {
            console.log(chalk.yellow(`Removing build in ${chalk.blueBright(linkDir)}`));

            await fs.remove(linkDir);
        } else if (!fs.existsSync(linkDir)) {
            console.log(chalk.green(`Copying build to ${chalk.blueBright(linkDir)}`));
            await fs.symlink(path.resolve('./dist'), linkDir);
        }
        return Promise.resolve();
    } catch (err) {
        Promise.reject(err);
    }
}

/*********************/
/*		PACKAGE		 */
/*********************/

/**
 * Update version and URLs in the manifest JSON
 */
function updateManifest(cb) {
    const packageJson = fs.readJSONSync('package.json');
    const packageLockJson = fs.readJSONSync('package-lock.json');
    const manifest = getManifest();

    if (!manifest) cb(Error(chalk.red('Manifest JSON not found')));

    try {
        const version = argv.update || argv.u;

        /* Update version */

        const versionMatch = /^(\d{1,}).(\d{1,}).(\d{1,})$/;
        const currentVersion = manifest.file.version;
        let targetVersion = '';

        if (!version) {
            cb(Error('Missing version number'));
        }

        if (versionMatch.test(version)) {
            targetVersion = version;
        } else {
            targetVersion = currentVersion.replace(versionMatch, (substring, major, minor, patch) => {
                console.log(substring, Number(major) + 1, Number(minor) + 1, Number(patch) + 1);
                if (version === 'major') {
                    return `${Number(major) + 1}.0.0`;
                } else if (version === 'minor') {
                    return `${major}.${Number(minor) + 1}.0`;
                } else if (version === 'patch') {
                    return `${major}.${minor}.${Number(patch) + 1}`;
                } else {
                    return '';
                }
            });
        }

        if (targetVersion === '') {
            return cb(Error(chalk.red('Error: Incorrect version arguments.')));
        }

        if (targetVersion === currentVersion) {
            return cb(Error(chalk.red('Error: Target version is identical to current version.')));
        }
        console.log(`Updating version number to '${targetVersion}'`);

        packageJson.version = targetVersion;
        packageLockJson.version = targetVersion;
        manifest.file.version = targetVersion;

        /* Update URL */
        const result = `https://git.f3l.de/ghost/${packageJson.name}/-/jobs/artifacts/${targetVersion}/download?job=build`;

        manifest.file.download = result;

        const prettyProjectJson =
            stringify(manifest.file, {
                maxLength: 40,
                indent: 4,
            }) + '\n';

        fs.writeJSONSync('package.json', packageJson, { spaces: 4 });
        fs.writeJSONSync('package-lock.json', packageLockJson, { spaces: 4 });
        fs.writeFileSync(path.join(manifest.root, manifest.name), prettyProjectJson, 'utf8');

        return cb();
    } catch (err) {
        cb(err);
    }
}

const execBuild = gulp.parallel(buildTS, copyFiles);

exports.build = gulp.series(clean, execBuild);
exports.watch = buildWatch;
exports.clean = clean;
exports.link = linkUserData;
exports.updateManifest = updateManifest;