/* global CodeMirror window document Set */
/* eslint-disable no-implicit-globals */

// CodeMirror
var editor = CodeMirror.fromTextArea(document.getElementById('code'), {
    lineNumbers: true,
    styleActiveLine: true,
    matchBrackets: true,
    theme: 'pastel-on-dark',
    lineWrapping: true
});

// CodeMirror theme selector
var input = document.getElementById('select-theme');

var font_data;
var filters = {
    'style': false,
    'rendering': false,
    'liga': false,
    'zerostyle': false,
    'author': 'all',
    'name': ''
};

function selectTheme() {
    var theme = 'monokai';

    if (input.selectedIndex > -1) {
        theme = input.options[input.selectedIndex].innerHTML;
    }
    editor.setOption('theme', theme);
    document.cookie = 'theme=' + theme + ';max-age=172800';
}

// ProgrammingFonts font selector
function selectFont() {
    var font = window.location.hash.substring(1);
    var status_msg = document.querySelector('footer .subtitle');
    var code_mirror = document.querySelector('.CodeMirror');

    if (! font) {
        font = 'cartograph';
        status_msg.innerHTML = 'Test drive all the programming fonts!';
    } else if (typeof font_data !== 'undefined') {
        status_msg.innerHTML = 'Test drive <a rel="external" href="' + font_data[font].website + '">' + font_data[font].name + '!</a>';
    }

    if (typeof font_data !== 'undefined' && font_data[font].rendering === 'bitmap') {
        code_mirror.classList.add('no-smooth');
    } else {
        code_mirror.classList.remove('no-smooth');
    }

    if (font === 'input') {
        code_mirror.style.fontFamily = 'Input Mono, monospace';
        code_mirror.querySelectorAll('pre, textarea').forEach(function(element){
            element.style.fontFamily = 'Input Mono, monospace';
        });
    } else {
        code_mirror.style.fontFamily = font + ', monospace';
        code_mirror.querySelectorAll('pre, textarea').forEach(function(element){
            element.style.fontFamily = font + ', monospace';
        });
    }

    document.querySelectorAll('#select-font [data-alias]').forEach(function(element) {
        element.classList.remove('active');
    });
    document.querySelectorAll('#select-font [data-alias=\'' + font + '\']').forEach(function(element) {
        element.classList.add('active');
    });

    document.cookie = 'font=' + font + ';max-age=172800';
}

window.onhashchange = selectFont;

function setSize() {
    var size = document.getElementById('size').value;

    document.querySelector('.CodeMirror').style.fontSize = size + 'px';
    document.cookie = 'size=' + size + ';max-age=172800';
}
function setSpacing() {
    var spacing = document.getElementById('spacing').value;

    document.querySelector('.CodeMirror').style.lineHeight = spacing;
    document.cookie = 'spacing=' + spacing + ';max-age=172800';
}
function selectLanguage() {
    var lang = document.getElementById('select-language').value;

    editor.setOption('mode', lang.toLowerCase());
    document.cookie = 'language=' + lang + ';max-age=172800';
}
function setCounter(amount) {
    var counter_element = document.querySelector('h1 a:first-child');
    if (amount === 1) {
        counter_element.innerHTML = amount + ' Programming Font';
    } else {
        counter_element.innerHTML = amount + ' Programming Fonts';
    }
}

function applyFilters() {
    var count = 0;

    Object.keys(filters).forEach(function(filter) {
        var button = document.querySelector('button[value="' + filter + '"]');
        if (! button) {
            return;
        }
        if (filters[filter]) {
            button.classList.add('selected');
            button.querySelectorAll('svg').forEach(function(image){
                image.classList.remove('selected');
            });
            button.querySelector('svg[alt="' + filters[filter] + '"]').classList.add('selected');
        } else {
            button.classList.remove('selected');
            button.querySelectorAll('svg').forEach(function(image){
                image.classList.remove('selected');
            });
        }
    });

    document.querySelectorAll('.entry[data-alias]').forEach(function(element) {
        var data = font_data[element.dataset.alias];
        if (
            (!filters.style || data.style === filters.style) &&
            (!filters.rendering || data.rendering === filters.rendering) &&
            (!filters.liga || data.ligatures === false && filters.liga === 'no' || data.ligatures === true && filters.liga === 'yes') &&
            (!filters.zerostyle || data.zerostyle === filters.zerostyle) &&
            (filters.author === 'all' || data.author === filters.author) &&
            (!filters.name || data.name.toLowerCase().indexOf(filters.name) > -1)
        ) {
            element.classList.remove('filtered-out');
            count++;
        } else {
            element.classList.add('filtered-out');
        }
    });

    setCounter(count);
}

function renderSelectList() {
    var icon = '<svg class="octicon" viewBox="0 0 12 14" version="1.1" width="12" height="14" aria-hidden="true"><path fill-rule="evenodd" d="M11 10h1v3c0 .55-.45 1-1 1H1c-.55 0-1-.45-1-1V3c0-.55.45-1 1-1h3v1H1v10h10v-3zM6 2l2.25 2.25L5 7.5 6.5 9l3.25-3.25L12 8V2H6z"></path></svg>';
    var pinIcon = '<svg class="octicon octicon-pin" viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M10 1.2V2l.5 1L6 6H2.2c-.44 0-.67.53-.34.86L5 10l-4 5 5-4 3.14 3.14a.5.5 0 0 0 .86-.34V10l3-4.5 1 .5h.8c.44 0 .67-.53.34-.86L10.86.86a.5.5 0 0 0-.86.34z"></path></svg>';
    var favoritesMap = {};
    var favorites = [];
    var ajax = new XMLHttpRequest();

    document.getElementById('select-font').innerHTML = '';

    try {
        favorites = JSON.parse(localStorage.getItem('favorites')) || [];
        favoritesMap = favorites.reduce(function(acc, alias) {
            acc[alias] = true;
            return acc;
        }, {});
    } catch (err) {
        // eslint-disable-next-line no-console
        console.error('could not render favorites', err);
    }

    ajax.onreadystatechange = function() {
        var fonts = [];
        var authors = [];
        if (ajax.readyState === 4 && ajax.status === 200) {
            font_data = ajax.response;

            Object.keys(font_data).forEach(function(key){
                var v= font_data[key];
                v.alias = key;
                fonts.push(v);
                if (authors.indexOf(v.author) < 0) {
                    authors.push(v.author);
                }
            });
        }

        authors.sort();
        fonts.sort(function(a, b) {
            if (favoritesMap[a.alias] && !favoritesMap[b.alias]) {return -1;}
            if (!favoritesMap[a.alias] && favoritesMap[b.alias]) {return 1;}
            if (a.name.toLowerCase() < b.name.toLowerCase()) {return -1;}
            if (a.name.toLowerCase() > b.name.toLowerCase()) {return 1;}
            return 0;
        });

        authors.forEach(function(author) {
            var option = document.createElement('option');
            option.innerHTML = author;
            document.getElementById('authors-list').querySelector('.other').appendChild(option);
        });

        fonts.forEach(function(v) {
            var option = document.createElement('div');

            option.classList.add('entry');
            if (favoritesMap[v.alias]) {
                option.classList.add('pinned');
            }

            option.setAttribute('data-alias', v.alias);
            option.innerHTML = '<a href="#' + v.alias + '" data-style="' + v.style + '">' +
                '<span class="name">' + v.name + '</span>' +
                '<span class="details">' + v.year + ' — ' + v.author + '</span>' +
                '</a>' +
                '<a class="favoritelink" onclick="toggleFavorite(\'' + v.alias + '\')">' +
                    pinIcon +
                '</a>' +
                '<a class="website" href="' + v.website + '" rel="external"> <span>Website</span>' + icon + '</a>';

            document.getElementById('select-font').appendChild(option);
        });

        selectFont();
        applyFilters();
    };
    ajax.responseType = 'json';
    ajax.open('GET', 'fonts.json', true);
    ajax.send();
}

// eslint-disable-next-line no-unused-vars
function toggleFavorite(alias) {
    var favorites = [];
    try {
        favorites = JSON.parse(localStorage.getItem('favorites')) || [];
        if (favorites.indexOf(alias) > -1) {
            favorites = favorites.filter(function(v) {
                return v !== alias;
            });
        } else {
            favorites.push(alias);
        }
        localStorage.setItem('favorites', JSON.stringify(Array.from(new Set(favorites))));
    } catch (err) {
        // eslint-disable-next-line no-console
        console.error('could not save favorite', err);
    }
    renderSelectList();
    return false;
}

function walk(direction) {
    var activeEntry = document.querySelector('.entry.active');
    var target = null;
    var next = direction === 'up' ? activeEntry.previousElementSibling : activeEntry.nextElementSibling;

    while (target === null) {
        if (next) {
            if (next.matches('.entry:not(.filtered-out)')) {
                target = next;
            } else {
                next = direction === 'up' ? next.previousElementSibling : next.nextElementSibling;
            }
        } else {
            target = false;
        }
    }

    function isVisible(el) {
        var offset = document.getElementById('filters').getBoundingClientRect().height;
        var container = document.querySelector('section.select-list').getBoundingClientRect().height;
        if (direction === 'up') {
            if (el.getBoundingClientRect().top < offset) {
                return false;
            }
        } else {
            if (el.getBoundingClientRect().bottom > offset + container) {
                return false;
            }
        }

        return true;
    }

    if (target) {
        target.querySelector('a').click();
        if (!isVisible(target)){
            target.scrollIntoView();
        }
    }
}

function increaseFontSize() {
    var sizeEl = document.getElementById('size');
    sizeEl.value = Number(sizeEl.value) + 1;
    sizeEl.onchange();
}

function decreaseFontSize() {
    var sizeEl = document.getElementById('size');
    sizeEl.value = Number(sizeEl.value) - 1;
    sizeEl.onchange();
}

function toggleFilter(filter) {
    // cycle through the possible values for each filter
    // and set the filters[filter] value,
    // or at the end of the cycle set it to false
    var options = {
        'style': [false, 'sans', 'serif'],
        'rendering': [false, 'vector', 'bitmap'],
        'liga': [false, 'yes', 'no'],
        'zerostyle': [false, 'slashed', 'dotted', 'empty'],
    };

    var current_index = options[filter].indexOf(filters[filter]);
    var next = current_index + 1;
    if (next < options[filter].length) {
        filters[filter] = options[filter][next];
    } else {
        filters[filter] = options[filter][0];
    }

    applyFilters();
}

window.addEventListener('DOMContentLoaded', function() {
    var cookieValueSpacing = document.cookie.replace(/(?:(?:^|.*;\s*)spacing\s*=\s*([^;]*).*$)|^.*$/, '$1');
    var cookieValueSize = document.cookie.replace(/(?:(?:^|.*;\s*)size\s*=\s*([^;]*).*$)|^.*$/, '$1');
    var cookieValueTheme = document.cookie.replace(/(?:(?:^|.*;\s*)theme\s*=\s*([^;]*).*$)|^.*$/, '$1');
    var cookieValueLanguage = document.cookie.replace(/(?:(?:^|.*;\s*)language\s*=\s*([^;]*).*$)|^.*$/, '$1');

    if (cookieValueSpacing !== '') {
        document.getElementById('spacing').value = cookieValueSpacing;
    }
    if (cookieValueSize !== '') {
        document.getElementById('size').value = cookieValueSize;
    }
    if (cookieValueTheme !== '') {
        document.getElementById('select-theme').value = cookieValueTheme;
    }
    if (cookieValueLanguage !== '') {
        document.getElementById('select-language').value = cookieValueLanguage;
    }

    renderSelectList();
    selectTheme();
    setSize();
    setSpacing();
    selectLanguage();

    function walkThemes(direction) {
        var select = document.getElementById('select-theme');
        var current = select.selectedOptions[0];
        var next;
        if (current) {
            next = direction === 'up' ? current.previousElementSibling : current.nextElementSibling;
        }
        if (next) {
            select.value = next.value;
        }
        selectTheme();
    }

    document.getElementById('theme-next').onclick = function() {
        walkThemes('down');
    };

    document.getElementById('theme-previous').onclick = function() {
        walkThemes('up');
    };

    document.getElementById('filters').querySelectorAll('button').forEach(function(button){
        button.onclick = function(event) {
            event.preventDefault();
            event.stopPropagation();
            toggleFilter(button.value);
        };
    });

    document.getElementById('authors-list').onchange = function(event) {
        filters.author = event.target.value;
        applyFilters();
    };

    document.getElementById('name-search').onkeyup = function(event) {
        filters.name = event.target.value.toLowerCase();
        applyFilters();
    };

    document.querySelector('.select-list').onkeyup = function(event) {
        if (event.ctrlKey || event.altKey || event.metaKey || event.shiftKey) {
            return;
        }
        if (event.key === 'ArrowUp') {
            event.preventDefault();
            event.stopPropagation();
            walk('up');
        } else if (event.key === 'ArrowDown') {
            event.preventDefault();
            event.stopPropagation();
            walk('down');
        }
    };

    document.body.addEventListener('keydown', function(event) {
        if (event.ctrlKey || event.metaKey) {
            if (event.key === '-') {
                event.preventDefault();
                event.stopPropagation();
                decreaseFontSize();
            } else if (event.key === '=') {
                event.preventDefault();
                event.stopPropagation();
                increaseFontSize();
            }
        }
    });
});