const buildUtils = require("./buildutils");
const fs = require("fs");
const path = require("path");
const crypto = require("crypto");
const { BUILD_VARIANTS } = require("./build_variants");

function computeIntegrityHash(fullPath, algorithm = "sha256") {
    const file = fs.readFileSync(fullPath);
    const hash = crypto.createHash(algorithm).update(file).digest("base64");
    return algorithm + "-" + hash;
}

/**
 * PROVIDES (per <variant>)
 *
 * html.<variant>.dev
 * html.<variant>.prod
 */
function gulptasksHTML($, gulp, buildFolder) {
    const commitHash = buildUtils.getRevision();
    async function buildHtml({
        googleAnalytics = false,
        standalone = false,
        integrity = true,
        enableCachebust = true,
    }) {
        function cachebust(url) {
            if (enableCachebust) {
                return buildUtils.cachebust(url, commitHash);
            }
            return url;
        }

        const hasLocalFiles = standalone;

        return gulp
            .src("../src/html/" + (standalone ? "index.standalone.html" : "index.html"))
            .pipe(
                $.dom(
                    /** @this {Document} **/ function () {
                        const document = this;

                        // Append css
                        const css = document.createElement("link");
                        css.rel = "stylesheet";
                        css.type = "text/css";
                        css.media = "none";
                        css.setAttribute("onload", "this.media='all'");
                        css.href = cachebust("main.css");
                        if (integrity) {
                            css.setAttribute(
                                "integrity",
                                computeIntegrityHash(path.join(buildFolder, "main.css"))
                            );
                        }
                        document.head.appendChild(css);

                        // Google analytics
                        if (googleAnalytics) {
                            const tagManagerScript = document.createElement("script");
                            tagManagerScript.src =
                                "https://www.googletagmanager.com/gtag/js?id=UA-165342524-1";
                            tagManagerScript.setAttribute("async", "");
                            document.head.appendChild(tagManagerScript);

                            const initScript = document.createElement("script");
                            initScript.textContent = `
                        window.dataLayer = window.dataLayer || [];
                        function gtag(){dataLayer.push(arguments);}
                        gtag('js', new Date());
                        gtag('config', 'UA-165342524-1', { anonymize_ip: true });
                        `;
                            document.head.appendChild(initScript);
                        }

                        // Do not need to preload in app or standalone
                        if (!hasLocalFiles) {
                            // Preload essentials
                            const preloads = ["fonts/GameFont.woff2"];

                            preloads.forEach(src => {
                                const preloadLink = document.createElement("link");
                                preloadLink.rel = "preload";
                                preloadLink.href = cachebust("res/" + src);
                                if (src.endsWith(".woff2")) {
                                    preloadLink.setAttribute("crossorigin", "anonymous");
                                    preloadLink.setAttribute("as", "font");
                                } else {
                                    preloadLink.setAttribute("as", "image");
                                }
                                document.head.appendChild(preloadLink);
                            });
                        }

                        const loadingSvg = `background-image: url("data:image/svg+xml;base64,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")`;

                        const loadingCss = `
                    @font-face {
                        font-family: 'GameFont';
                        font-style: normal;
                        font-weight: normal;
                        font-display: swap;
                        src: url('${cachebust("res/fonts/GameFont.woff2")}') format('woff2');
                    }

                    #ll_fp {
                        font-family: GameFont;
                        font-size: 14px;
                        position: fixed;
                        z-index: -1;
                        top: 0;
                        left: 0;
                        opacity: 0.05;
                    }

                    #ll_p {
                        display: flex;
                        position: fixed;
                        z-index: 99999;
                        top: 0;
                        left: 0;
                        right: 0;
                        bottom: 0;
                        justify-content:
                        center;
                        align-items: center;
                    }

                    #ll_p > div {
                        position: absolute;
                        text-align: center;
                        bottom: 40px;
                        left: 20px;
                        right: 20px;
                        color: #393747;
                        font-family: 'GameFont', sans-serif;
                        font-size: 20px;
                    }

                    #ll_p > span {
                        width: 60px;
                        height: 60px;
                        display: inline-flex;
                        background: center center / contain no-repeat;
                        ${loadingSvg};
                    }
                `;

                        const style = document.createElement("style");
                        style.setAttribute("type", "text/css");
                        style.textContent = loadingCss;
                        document.head.appendChild(style);

                        // Append loader, but not in standalone (directly include bundle there)
                        if (standalone) {
                            const bundleScript = document.createElement("script");
                            bundleScript.type = "text/javascript";
                            bundleScript.src = "bundle.js";
                            if (integrity) {
                                bundleScript.setAttribute(
                                    "integrity",
                                    computeIntegrityHash(path.join(buildFolder, "bundle.js"))
                                );
                            }
                            document.head.appendChild(bundleScript);
                        } else {
                            const loadJs = document.createElement("script");
                            loadJs.type = "text/javascript";
                            let scriptContent = "";
                            scriptContent += `var bundleSrc = '${cachebust("bundle.js")}';\n`;
                            scriptContent += `var bundleSrcTranspiled = '${cachebust(
                                "bundle-transpiled.js"
                            )}';\n`;

                            if (integrity) {
                                scriptContent +=
                                    "var bundleIntegrity = '" +
                                    computeIntegrityHash(path.join(buildFolder, "bundle.js")) +
                                    "';\n";
                                scriptContent +=
                                    "var bundleIntegrityTranspiled = '" +
                                    computeIntegrityHash(path.join(buildFolder, "bundle-transpiled.js")) +
                                    "';\n";
                            } else {
                                scriptContent += "var bundleIntegrity = null;\n";
                                scriptContent += "var bundleIntegrityTranspiled = null;\n";
                            }

                            scriptContent += fs.readFileSync("./bundle-loader.js").toString();
                            loadJs.textContent = scriptContent;
                            document.head.appendChild(loadJs);
                        }

                        const bodyContent = `
                <div id="ll_fp">_</div>
                <div id="ll_p">
                    <span></span>
                    <div>${hasLocalFiles ? "Loading" : "Downloading"} Game Files</div >
                </div >
                `;

                        document.body.innerHTML = bodyContent;
                    }
                )
            )
            .pipe(
                $.htmlmin({
                    caseSensitive: true,
                    collapseBooleanAttributes: true,
                    collapseInlineTagWhitespace: true,
                    collapseWhitespace: true,
                    preserveLineBreaks: true,
                    minifyJS: true,
                    minifyCSS: true,
                    quoteCharacter: '"',
                    useShortDoctype: true,
                })
            )
            .pipe($.htmlBeautify())
            .pipe($.rename("index.html"))
            .pipe(gulp.dest(buildFolder));
    }

    for (const variant in BUILD_VARIANTS) {
        const data = BUILD_VARIANTS[variant];
        gulp.task("html." + variant + ".dev", () => {
            return buildHtml({
                googleAnalytics: false,
                standalone: data.standalone,
                integrity: false,
                enableCachebust: false,
            });
        });
        gulp.task("html." + variant + ".prod", () => {
            return buildHtml({
                googleAnalytics: !data.standalone,
                standalone: data.standalone,
                integrity: true,
                enableCachebust: !data.standalone,
            });
        });
    }
}

module.exports = {
    gulptasksHTML,
};