// convert our markdown documentation files
// to 'static' html/ejs partials:
// while this is a bit inconvenient (you need to restart
// the server everytime you want to see
// md changes), it is more efficient in
// that we aren't converting MD -> ejs
// on EVERY request
const showdown = require('showdown'),
    showdownHighlight = require("showdown-highlight"),
    fs = require('fs'),
    mkdirp = require('mkdirp'),
    recipeInputDir = './recipes/',
    recipeOutputDir = './views/partials/md/recipes/',
    recipeListGeneratedOutputDir = './views/partials/generated/',
    projectClassMap = {
        h1: 'display-1' //tag type : class to add to all tags of that type (class="display-1" added to all <h1>)
    };
const { assert } = require('console');


function addClassToTag(text, classMap) {
    var modifiedText = text;
    Object.keys(classMap).forEach(function (key) {
        var regex = new RegExp(`<(${key})(.*?)>`, 'g');
        matcher = regex.exec(modifiedText);

        // only proceed if we found a match, and the class we add isn't already on the tag somehow
        while (matcher != null && !matcher[2].includes(classMap[key])) {
            // add the class content WHILE preserving any other properties already in the tag!
            console.log("adding class content in: " + matcher[0]);

            var restOfTag = matcher[2];
            modifiedText = modifiedText.replace(matcher[0], `<${key} class="${classMap[key]}" ${restOfTag}>`);

            matcher = regex.exec(modifiedText);
        }
    });
    return modifiedText;
}

// handles adding classes to specific
// tag types automatically in project writeups
const projectsAddHeaderClass = {
    type: 'output', // when it's triggered -> output is at the very end when text is html
    filter: text => { return addClassToTag(text, projectClassMap); }
};

function convertRecipeMarkdown(inputDir, outputDir) {
    var md = require('markdown-it')()
        .use(require('markdown-it-hashtag'));

    md.renderer.rules.hashtag_open = function (tokens, idx) {
        var tagName = tokens[idx].content.toLowerCase();
        return '<a href="/recipe_navigator?tag=' + tagName + '"><span class="badge bg-secondary">';
    }

    md.renderer.rules.hashtag_close = function () { return '</span></a>'; }

    // This is a hardcoded markdown header section number to html file name
    //
    // Example.md:
    // """
    // ... maybe some other header info here   -| - exported as filename-title.ejs
    // # Delicious Recipe Name                 -|
    // Catch phrase or yield        -|
    //                               | - exported as filename-subtitle
    // image of the food             |
    //                              -|
    // ## Ingredients              -|
    //  ... ingredients table, etc  | - exported as filename-ingredients.ejs
    //                             -|
    // ## Instructions
    // """
    //
    // NOTE: these titles are HARDCODED in recipe_template.ejs!
    const mdSectionHtmlTitles = [
        'title',
        // 'subtitle',
        'ingredients',
        'instructions',
    ]

    mkdirp.sync(outputDir);
    fs.readdir(inputDir, (err, files) => {
        files.forEach(file => {
            if (!file.endsWith('.md')) {
                return;
            }
            let fileNameNoExtension = file.slice(0, -3);
            console.log('converting: ' + fileNameNoExtension);
            fs.readFile(inputDir + file, 'utf8', (err, data) => {
                if (err) {
                    console.error(err);
                    return;
                }

                var ingredientTableRegex = new RegExp(`^(\\|?.*?)\\|(.*?)(\\|.*?\\|.*?)\n`, `gm`);
                var ingredientDashCheck = new RegExp("^\-+$");
                ingredientTableMatcher = ingredientTableRegex.exec(data);
                while (ingredientTableMatcher != null) {
                    meas = ingredientTableMatcher[1];
                    let unit = ingredientTableMatcher[2].toLowerCase().trim();
                    if (unit != "unit" && unit && !ingredientDashCheck.test(unit)) {
                        meas += unit + " ";
                    }
                    data = data.replace(ingredientTableMatcher[0], `${meas}${ingredientTableMatcher[3]}\n`);
                    ingredientTableMatcher = ingredientTableRegex.exec(data);
                }
                ingredientTableMatcher = ingredientTableRegex.exec(data);
                while (ingredientTableMatcher != null) {
                    meas = ingredientTableMatcher[1];
                    let unit = ingredientTableMatcher[2].toLowerCase().trim();
                    if (unit != "unit" && unit && !ingredientDashCheck.test(unit)) {
                        meas += unit + " ";
                    }
                    data = data.replace(ingredientTableMatcher[0], `${meas}${ingredientTableMatcher[3]}\n`);
                    ingredientTableMatcher = ingredientTableRegex.exec(data);
                }

                let tokens = md.parse(data)

                let sections = []
                sections.push([]); // start off the array and put everything before and including the first header in title
                let numSections = 0;
                for (const token of tokens) {
                    if (token.type === 'heading_open') {
                        if (numSections == 0) {
                            numSections++;
                        }
                        else if (numSections < mdSectionHtmlTitles.length) {
                            numSections++;
                            sections.push([]);
                        }
                    }
                    sections[sections.length - 1].push(token)
                }

                assert(sections.length <= mdSectionHtmlTitles.length);

                // hardcode bootstrap class attribute to add to <table> tag in ingredients
                for (let ii = 0; ii < sections[1].length; ii++) {
                    if (sections[1][ii].type == 'table_open') {
                        sections[1][ii].attrs = [["class", "table table-striped table-sm table-hover"]];
                        break;
                    }
                }

                for (let ii = 0; ii < sections.length; ii++) {
                    let html = md.renderer.render(sections[ii], md.options);
                    // hardcode making images in the title section larger
                    if (ii == 0) {
                        var regex = new RegExp(`<img (.*?)>`, `g`);
                        matcher = regex.exec(html);
                        while (matcher != null && !matcher[1].includes("w-100")) {
                            var restOfTag = matcher[1];
                            html = html.replace(matcher[0], `<img class="w-100" ${restOfTag}>`);
                            matcher = regex.exec(html);
                        }
                    }
                    fs.writeFileSync(outputDir + fileNameNoExtension + '-' + mdSectionHtmlTitles[ii] + '.ejs', html, 'utf8');
                }
            });
        });
    });
}

function generateRecipeNavigatorList(recipeSrcDir, generatedOutputDir) {
    // generate a list of recipe links. While doing so generate an array
    // of unique hashtags found in all recipes
    mkdirp.sync(generatedOutputDir);
    let recipeListPartialOut = "";
    let allRecipeHashtags = [];
    fs.readdir(recipeSrcDir, (err, files) => {
        files.sort().forEach(file => {
            if (!file.endsWith('.md')) {
                return;
            }
            let fileNameNoExtension = file.slice(0, -3);

            const data = fs.readFileSync(recipeSrcDir + file, { encoding: 'utf8', flag: 'r' });

            // find all hashtags in the file
            var hashtagRegex = new RegExp(`#(\\w+)`, `g`);
            hashtagMatcher = hashtagRegex.exec(data);
            var recipeTags = []; // hashtags of the current recipe only
            while (hashtagMatcher != null) {
                var hashtag = hashtagMatcher[1].toLowerCase();
                if (!allRecipeHashtags.includes(hashtag)) {
                    allRecipeHashtags.push(hashtag);
                }
                if (!recipeTags.includes(hashtag)) {
                    recipeTags.push(hashtag);
                }
                hashtagMatcher = hashtagRegex.exec(data);
            }

            let combinedRecipeTags = "";
            if (recipeTags.length > 0) {
                combinedRecipeTags = recipeTags.join(",");
            }

            // get first recipe title from document
            var titleRegex = new RegExp(`#\\s+(.+)\\n`, `g`);
            titleMatcher = titleRegex.exec(data);
            var recipeTitle = fileNameNoExtension;
            if (titleMatcher != null) {
                recipeTitle = titleMatcher[1];
            }

            recipeListPartialOut += `<a href="recipes/${fileNameNoExtension}" class="list-group-item list-group-item-action" tags="${combinedRecipeTags}">${recipeTitle}</a>\n`;
        });

        // writeout the link list partial
        fs.writeFileSync(generatedOutputDir + "recipe-links.ejs", recipeListPartialOut, "utf-8");

        // now generate the  hashtag button list partial
        // TODO: in the future sort the list by number of hashtag hits (most -> least common)
        //      instead of alphabetically
        let tagListPartialOut = "";
        allRecipeHashtags.sort().forEach(hashtag => {
            tagListPartialOut += `<button type="button" class="btn btn-light btn-sm">${hashtag}</button>\n`;
        });
        fs.writeFileSync(generatedOutputDir + "recipe-tags.ejs", tagListPartialOut, "utf-8");
    });
}

convertRecipeMarkdown(recipeInputDir, recipeOutputDir);
generateRecipeNavigatorList(recipeInputDir, recipeListGeneratedOutputDir);