$(document).ready(function() {
    var bitsyData = {};

    var palette = {
        background: {
            red: 62, 
            green: 43, 
            blue: 32,
        },
        tile: {
            red: 208, 
            green: 112, 
            blue: 56,
        },
        sprite: {
            red: 229, 
            green: 92, 
            blue: 68,
        }
    };

    var croptions = {
        url: 'https://i.imgur.com/ThQZ94v.jpg',
        viewport: {width: 128, height: 128, type: 'square'},
        boundary: {width: 256, height: 256},
        zoom: 0
    }

    var $croppie = $('#croppie');
    var croppie  = $croppie.croppie(croptions);

    function colourDifference(colour1, colour2) {
        difference = {};

        _.each(['red', 'green', 'blue'], function(key) {
            difference[key] = Math.abs(colour1[key] - colour2[key]);
        });

        // sum rgb differences
        return _.reduce(difference, function(sum, n) {
          return sum + n;
        }, 0);
    }

    function colourToHex(colour) {
        return '#' + Number(colour.red).toString(16) + Number(colour.green).toString(16) + Number(colour.blue).toString(16);
    }

    function hexToColour(hex) {
        var rgb = hex.match(/[\da-fA-F]{2}/g);

        return {
            red:   parseInt(rgb[0], 16),
            green: parseInt(rgb[1], 16),
            blue:  parseInt(rgb[2], 16),
        };
    }

    function getClosestColour(initialColour, colourOptions) {
        // ditch sprite colour as we're not using it atm
        delete colourOptions.sprite;

        _.each(palette, function(colour, name) {
            colourOptions[name].difference = colourDifference(initialColour, colour);
        });

        // lowest difference (closest) wins
        return _.first(_.sortBy(colourOptions, 'difference'));
    }

    function handleBitsyGameData() {
        bitsyData = {};

        var input = $('#bitsy-data').val();

        // get palettes
        var palettes = input.match(/PAL (.*)\s(NAME (.*)\s)?([0-9,]*[\s]){3}/g);

        bitsyData.palettes = {};
        
        _.each(palettes, function(palette, n) {
            var thisPalette = {};
            var name = "";

            if (palette.match(/NAME (.+)\n/)) {
                name = palette.match(/NAME (.+)\n/)[0].replace('NAME ', '');
            } else if (palette.match(/PAL (\d+)\n/)) {
                name = palette.match(/PAL (\d+)\n/)[0].replace("PAL", "palette");
            }

            var colours = palette.match(/\d+,\d+,\d+/g);

            colours = _.map(colours, function(colour) {
                var rgb = colour.split(',');

                return {red: rgb[0], green: rgb[1], blue: rgb[2]};
            });

            bitsyData.palettes[name] = {
                sortOrder:  n,
                background: colours[0],
                tile:       colours[1],
                sprite:     colours[2],
            }
        });

        // set palette to first imported palette and redraw
        palette = _.first(_.sortBy(bitsyData.palettes, 'sortOrder'));

        renderResult();

        // update palette picker
        $('tr.palette').remove();

        _.each(bitsyData.palettes, function(palette, name) {
            $('#palette tbody').append(
                '<tr class="palette">'
                  + '<td><input type="radio" name="palette" id="palette-' + name + '"></td>'
                  + '<td><label for="palette-' + name + '">' + name + '</label></td>'
                  + '<td><input type="color" name="background" value="' + colourToHex(palette.background) + '"></td>'
                  + '<td><input type="color" name="tile"       value="' + colourToHex(palette.tile)       + '"></td>'
                  + '<td><input type="color" name="sprite"     value="' + colourToHex(palette.sprite)     + '" disabled></td>'
              + '</tr>'
            );
        });

        $('tr.palette input[type="radio"]').eq(0).trigger('click');
    }

    function readFile(input) {
        if (input.files && input.files[0]) {
            var reader = new FileReader();
            
            reader.onload = function (e) {
                $croppie.croppie('bind', {
                    url: e.target.result,
                    zoom: 0
                });
            }
            
            reader.readAsDataURL(input.files[0]);
        }
    }

    var renderResult = _.debounce(function() {
        $croppie.croppie('result', {
            type: 'rawcanvas',
            size: 'viewport'
        }).then(function (result) {
            var imageData = result.getContext('2d').getImageData(0, 0, 128, 128);
            var rawData  = imageData.data;

            brightnessAdjustment = parseFloat($('#brightness').val());

            // for each pixel
            for (var i = 0; i < rawData.length; i += 4) {
                // this brightness adjustment is pretty crude but whatever
                var pixel = {
                    red:   Math.min(rawData[i    ] + brightnessAdjustment, 255),
                    green: Math.min(rawData[i + 1] + brightnessAdjustment, 255),
                    blue:  Math.min(rawData[i + 2] + brightnessAdjustment, 255),
                };

                var targetColour = getClosestColour(pixel, palette);

                rawData[i    ] = targetColour.red;
                rawData[i + 1] = targetColour.green;
                rawData[i + 2] = targetColour.blue;
            }

            document.getElementById('preview').getContext('2d').putImageData(imageData, 0, 0);  
        });
    }, 12);

    $croppie.on('update', renderResult);

    // make this not debounced but called every n milliseconds
    $('#brightness').on('change', renderResult);

    $('#brightness').on('dblclick', function() {
        $(this).val(0);
        renderResult();
    });

    $('label[for="brightness"]').on('click touchdown', function() {
        $('#brightness').trigger('dblclick');
    });

    $('#bitsy-data').on('change blur keyup', handleBitsyGameData);

    handleBitsyGameData();

    $('#imageUpload').on('change', function () {
        readFile(this);
    });

    $('#palette input').on('change', function() {
        // if this is a colour input, update the palette
        if ($(this).attr('type') === 'color') {
            palette[$(this).attr('name')] = hexToColour($(this).val());
        }

        // if this is a radio button, pick this palette
        if ($(this).attr('type') === 'radio') {
            palette.background = hexToColour($(this).closest('.palette').find('input[type="color"][name="background"]').val());
            palette.tile       = hexToColour($(this).closest('.palette').find('input[type="color"][name="tile"]').val());
        }

        renderResult();
    });
});