const path = require("path");
const { CleanWebpackPlugin } = require("clean-webpack-plugin");
const CopyPlugin = require("copy-webpack-plugin");
const Handlebars = require("handlebars");
const fs = require("fs");

const COLOR_KEYS = ["color", "bgColor", "fillcolor"];
const FRAGMENTS_PATH = "src/fragments";

// Transform the color names into colors defined in colors.mjs
const transformDataColors = async (data, path) => {
    const {getNamedColor} = await import('./src/colors.mjs');
    // if not json file, return
    if (!path.endsWith(".json")) {
        return data;
    }
    const parsedData = JSON.parse(data);
    // Change the color of the data
    const deepIterateAndSetColor = (key, val) => {
        if (val === null) {
            return null;
        }
        if (val == undefined) {
            return undefined;
        }
        if (Array.isArray(val)) {
            return val.map(item => deepIterateAndSetColor(key, item));
        }
        if (typeof val === "object") {
            return Object.entries(val).reduce((newObj, [key, value]) => {
                newObj[key] = deepIterateAndSetColor(key, value);
                return newObj;
            }, {});
        }
        if (COLOR_KEYS.includes(key)) {
            const [colorName, opacity, ...rest] = val.trim().split(/\s+/);
            const floatOpacity = parseFloat(opacity);
            const newColor = getNamedColor(colorName, floatOpacity);
            if (newColor !== undefined && rest.length === 0 && !isNaN(floatOpacity)) {
                console.log(`key: ${key} in file ${path} changed from ${val} to ${newColor}`);
                return newColor;
            } else {
                return val;
            }
        }
        return val;
    };
    return JSON.stringify(deepIterateAndSetColor(undefined, parsedData))
};


// Load the fragments from the fragments directory and caches it
const loadFragmentsMap = (() => {
    let cachedFragments = null;
    return async () => {
        if (cachedFragments === null) {
            cachedFragments = {};
            const walkDir = (dir, basePath = '') => {
                const files = fs.readdirSync(dir);
                files.forEach(file => {
                    const filePath = path.join(dir, file);
                    const relativePath = path.join(basePath, file);
                    if (fs.statSync(filePath).isDirectory()) {
                        walkDir(filePath, relativePath);
                    } else {
                        const dottedPath = relativePath.replace(/\\/g, '-').replace(/\//g, '-').replace(/\./g, '-');
                        cachedFragments[dottedPath] = fs.readFileSync(filePath, "utf8");
                    }
                });
            };
            walkDir(FRAGMENTS_PATH);
        }
        return cachedFragments;
    };
})();


const transformHandlebars = async (data, path) => {
    const fragments = await loadFragmentsMap();
    console.log(`Available fragments: ${Object.keys(fragments).join(', ')}`);
    // Load the template file
    const template = Handlebars.compile(data.toString('utf8'));
    const html = template(fragments);
    return html;
};

module.exports = {
    entry: {
        distill: "./src/distill.js",
        main: "./src/index.js",
    },
    output: {
        filename: "[name].bundle.js", // The output file
        path: path.resolve(__dirname, "dist"), // Output directory
    },
    module: {
        rules: [
            // { test: /\.css$/, use: ["style-loader", "css-loader"] },
            {
                test: /\.(js|mjs)$/,
                exclude: /node_modules/,
                use: {
                    loader: "babel-loader",
                    options: {
                        presets: ["@babel/preset-env"],
                    },
                },
            },
        ],
    },
    plugins: [
        new CleanWebpackPlugin(),
        new CopyPlugin({
            patterns: [
                {
                    from: "assets",
                    to: "assets",
                    transform: transformDataColors,
                },
                { from: "src/style.css", to: "style.css" },
                { from: "src/bibliography.bib", to: "bibliography.bib" },
                { 
                    from: "src/**/*.html.handlebars", 
                    to: ({context, absoluteFilename}) => {
                        const contextWithSrc = `${context}/src`;
                        const relativePath = absoluteFilename.replace(contextWithSrc, '').replace(/^\//, '');
                        const htmlPath = relativePath.replace(/\.handlebars$/, '');
                        return htmlPath;
                    },
                    transform: transformHandlebars, 
                    noErrorOnMissing: true
                },
            ],
        }),
    ],
    devtool: process.env.NODE_ENV === 'production' ? 'source-map' : 'eval-source-map',
    devServer: {
        static: "./dist", // Serve files from the 'dist' directory
        open: process.env.NODE_ENV !== 'production', // Automatically open the browser unless in production
        hot: process.env.NODE_ENV !== 'production', // Enable hot module replacement unless in production
    },
    mode: process.env.NODE_ENV === 'production' ? 'production' : 'development',
};

console.log(process.env.NODE_ENV)