// -----------------------------------------------------------------------------
// Permalink - Custom permalink and argparser
//
// Written in 2012 by Dominik Fässler
//
// To the extent possible under law, the author(s) have dedicated all copyright
// and related and neighboring rights to this software to the public domain
// worldwide. This software is distributed without any warranty.
//
// You should have received a copy of the CC0 Public Domain Dedication along
// with this software. If not, see
// <http://creativecommons.org/publicdomain/zero/1.0/>.
// -----------------------------------------------------------------------------


// -----------------------------------------------------------------------------
// Description
// -----------------------------------------------------------------------------
// The base OpenLayers.Control.Permalink can not handle dynamic layers. The
// solution was to introduce a 'layerId' for each layer. Now it is possible
// to change layer order without side effects.
//
// The 'layerId' is used to determine the position in the param string. So
// in the pattern 'BFFTFF', layers with id 1 and 4 are visible.
// -----------------------------------------------------------------------------


OpenSeaMap         = OpenLayers.Class(Object, {});
OpenSeaMap.Control = OpenLayers.Class(Object, {});


OpenSeaMap.Control.ArgParser = OpenLayers.Class(OpenLayers.Control.ArgParser, {
    configureLayers: function() {
        for (var i = 0, len = this.map.layers.length; i < len; i++) {
            var layer = this.map.layers[i];
            var id = layer.layerId || 0;
            if (id < 1) {
                // No layerId set -> ignore the layer
                continue;
            }
            if (this.layers.length < id) {
                // Setting for layer not in arguments
                continue;
            }
            var c = this.layers.charAt(id-1);
            if (c == 'B') {
                this.map.setBaseLayer(layer);
            } else if ((c == 'T') || (c == 'F')) {
                layer.setVisibility(c == 'T');
            }
        }
    }
});


OpenSeaMap.Control.Permalink = OpenLayers.Class(OpenLayers.Control.Permalink, {
    argParserClass: OpenSeaMap.Control.ArgParser,
    createParams: function(center, zoom, layers) {
        center = center || this.map.getCenter();

        var params = OpenLayers.Util.getParameters(this.base);

        if (center) {
            // Call parent method
            params = OpenLayers.Control.Permalink.prototype.createParams.apply(this, [center, zoom, layers]);

            // Override layers param
            layers = layers || this.map.layers;
            params.layers = '';
            for (var i = 0, len = layers.length; i < len; i++) {
                var layer = layers[i];
                var id = layer.layerId || 0;
                var flag;
                if (id < 1) {
                    // No layerId set -> ignore the layer
                    continue;
                }
                if (layer.isBaseLayer) {
                    flag = (layer == this.map.baseLayer) ? 'B' : '0';
                } else {
                    flag = (layer.getVisibility()) ? 'T' : 'F';
                }
                params.layers = this.setFlag(params.layers, flag, id);
            }
        }

        return params;
    },
    setFlag: function(config, flagValue, id) {
        // The layers can be in different order
        while (config.length < id) {
            // Fill with defaults
            config = config + 'F';
        }
        return config.substr(0, id-1) + flagValue + config.substr(id);
    }
});