var xmlUtil = require('raptor-xml/util');
var escapeXml = xmlUtil.escapeXml;
var escapeXmlAttr = xmlUtil.escapeXmlAttr;
var runtime = require('./raptor-templates'); // Circular dependnecy, but that is okay
var extend = require('raptor-util').extend;

function attr(context, name, value, escapeXml) {
    if (value === null || value === true) {
        value = '';
    } else if (value === undefined || value === false || typeof value === 'string' && value.trim() === '') {
        return;
    } else {
        value = '="' + (escapeXml === false ? value : escapeXmlAttr(value)) + '"';
    }
    context.write(' ' + name + value);
}

function notEmpty(o) {
    if (Array.isArray(o) === true) {
        return o.length !== 0;
    }
    return o;
}

module.exports = {
    fv: function (array, callback) {
        if (!array) {
            return;
        }
        if (!array.forEach) {
            array = [array];
        }
        var i = 0;
        var len = array.length;
        var loopStatus = {
                getLength: function () {
                    return len;
                },
                isLast: function () {
                    return i === len - 1;
                },
                isFirst: function () {
                    return i === 0;
                },
                getIndex: function () {
                    return i;
                }
            };
        for (; i < len; i++) {
            var o = array[i];
            callback(o || '', loopStatus);
        }
    },
    f: require('raptor-util').forEach,
    fl: function (array, func) {
        if (array != null) {
            if (!Array.isArray(array)) {
                array = [array];
            }
            func(array, 0, array.length);
        }
    },
    fp: function (o, func) {
        if (!o) {
            return;
        }
        for (var k in o) {
            if (o.hasOwnProperty(k)) {
                func(k, o[k]);
            }
        }
    },
    e: function (o) {
        return !notEmpty(o);
    },
    ne: notEmpty,
    x: escapeXml,
    xa: escapeXmlAttr,
    nx: function (str) {
        return {
            toString: function () {
                return str;
            }
        };
    },

    /* Helpers that require a context below: */
    t: function (context, handler, props, body, namespacedProps) {
        if (!props) {
            props = {};
        }
        props._tag = true;
        if (body) {
            props.invokeBody = body;
        }
        if (namespacedProps) {
            extend(props, namespacedProps);
        }

        var func;
        if (typeof handler === 'function') {
            func = handler;
        } else {
            func = handler.process || handler.render;
        }

        func.call(handler, props, context);
    },
    c: function (context, func) {
        var output = context.captureString(func);
        return {
            toString: function () {
                return output;
            }
        };
    },
    a: function(context, _attrs) {
        if (arguments.length !== 2) {
            attr.apply(context, arguments);
        } else if (_attrs) {
            for (var attrName in _attrs) {
                if (_attrs.hasOwnProperty(attrName)) {
                    attr(context, attrName, _attrs[attrName]);
                }
            }
        }
    },
    i: function(context, path, data, require) {
        if (typeof require === 'function') {
            path = require.resolve(path);
        }
        runtime.render(path, data, context);
        return this;
    }
};