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    if (theme === null || theme === undefined) { theme = 'light'; }

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    // Syntax highlighting Configuration
    hljs.configure({
        tabReplace: '    ', // 4 spaces
        languages: [],      // Languages used for auto-detection
    });
    
    if (window.ace) {
        // language-rust class needs to be removed for editable
        // blocks or highlightjs will capture events
        $('code.editable').removeClass('language-rust');

        $('code').not('.editable').each(function(i, block) {
            hljs.highlightBlock(block);
        });
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    function set_theme(theme) {
        let ace_theme;
        
        if (theme == 'coal' || theme == 'navy') {
            $("[href='ayu-highlight.css']").prop('disabled', true);
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        $('body').removeClass().addClass(theme);
    }


    // Hide Rust code lines prepended with a specific character
    var hiding_character = "#";

    $("code.language-rust").each(function(i, block){

        var code_block = $(this);
        var pre_block = $(this).parent();
        // hide lines
        var lines = code_block.html().split("\n");
        var first_non_hidden_line = false;
        var lines_hidden = false;

        for(var n = 0; n < lines.length; n++){
            if($.trim(lines[n])[0] == hiding_character){
                if(first_non_hidden_line){
                    lines[n] = "<span class=\"hidden\">" + "\n" + lines[n].replace(/(\s*)# ?/, "$1") + "</span>";
                }
                else {
                    lines[n] = "<span class=\"hidden\">" + lines[n].replace(/(\s*)# ?/, "$1") + "\n"  +  "</span>";
                }
                lines_hidden = true;
            }
            else if(first_non_hidden_line) {
                lines[n] = "\n" + lines[n];
            }
            else {
                first_non_hidden_line = true;
            }
        }
        code_block.html(lines.join(""));

        // If no lines were hidden, return
        if(!lines_hidden) { return; }

        // add expand button
        pre_block.prepend("<div class=\"buttons\"><i class=\"fa fa-expand\"></i></div>");

        pre_block.find("i").click(function(e){
            if( $(this).hasClass("fa-expand") ) {
                $(this).removeClass("fa-expand").addClass("fa-compress");
                pre_block.find("span.hidden").removeClass("hidden").addClass("unhidden");
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            else {
                $(this).removeClass("fa-compress").addClass("fa-expand");
                pre_block.find("span.unhidden").removeClass("unhidden").addClass("hidden");
            }
        });
    });

    // Process playpen code blocks
    $(".playpen").each(function(block){
        var pre_block = $(this);
        // Add play button
        var buttons = pre_block.find(".buttons");
        if( buttons.length === 0 ) {
            pre_block.prepend("<div class=\"buttons\"></div>");
            buttons = pre_block.find(".buttons");
        }
        buttons.prepend("<i class=\"fa fa-play play-button\"></i>");
        buttons.prepend("<i class=\"fa fa-copy clip-button\"><i class=\"tooltiptext\"></i></i>");

        let code_block = pre_block.find("code").first();
        if (window.ace && code_block.hasClass("editable")) {
            buttons.prepend("<i class=\"fa fa-history reset-button\"></i>");
        }

        buttons.find(".play-button").click(function(e){
            run_rust_code(pre_block);
        });
        buttons.find(".clip-button").mouseout(function(e){
            hideTooltip(e.currentTarget);
        });
        buttons.find(".reset-button").click(function() {
            if (!window.ace) { return; }
            let editor = window.ace.edit(code_block.get(0));
            editor.setValue(editor.originalCode);
            editor.clearSelection();
        });
    });

    var clipboardSnippets = new Clipboard('.clip-button', {
        text: function(trigger) {
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            let playpen = $(trigger).parents(".playpen");
            let code_block = playpen.find("code").first();

            if (window.ace && code_block.hasClass("editable")) {
                let editor = window.ace.edit(code_block.get(0));
                return editor.getValue();
            } else {
                return code_block.get(0).textContent;
            }
        }
    });
    clipboardSnippets.on('success', function(e) {
            e.clearSelection();
            showTooltip(e.trigger, "Copied!");
    });
    clipboardSnippets.on('error', function(e) {
            showTooltip(e.trigger, "Clipboard error!");
    });
});

function hideTooltip(elem) {
    elem.firstChild.innerText="";
    elem.setAttribute('class', 'fa fa-copy clip-button');
}

function showTooltip(elem, msg) {
    elem.firstChild.innerText=msg;
    elem.setAttribute('class', 'fa fa-copy tooltipped');
}

function sidebarToggle() {
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        store.set('sidebar', 'visible');
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        html.removeClass("sidebar-visible").addClass("sidebar-hidden");
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        if($("#sidebar").position().left === 0){
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            store.set('sidebar', 'hidden');
        } else {
            html.addClass("sidebar-visible");
            store.set('sidebar', 'visible');
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}

function run_rust_code(code_block) {
    var result_block = code_block.find(".result");
    if(result_block.length === 0) {
        code_block.append("<code class=\"result hljs language-bash\"></code>");
        result_block = code_block.find(".result");
    }

    let text;

    let inner_code_block = code_block.find("code").first();
    if (window.ace && inner_code_block.hasClass("editable")) {
        let editor = window.ace.edit(inner_code_block.get(0));
        text = editor.getValue();
    } else {
        text = inner_code_block.text();
    }

    var params = {
        version: "stable",
        optimize: "0",
        code: text,
    };

    if(text.indexOf("#![feature") !== -1) {
        params.version = "nightly";
    }

    result_block.text("Running...");

    $.ajax({
        url: "https://play.rust-lang.org/evaluate.json",
        method: "POST",
        crossDomain: true,
        dataType: "json",
        contentType: "application/json",
        data: JSON.stringify(params),
        timeout: 15000,
        success: function(response){
            result_block.text(response.result);
        },
        error: function(qXHR, textStatus, errorThrown){
            result_block.text("Playpen communication " + textStatus);
        },
    });
}