DaQuirm/nexus

var nx = {
    Mapping: require('./mapping')
};

nx.Binding = function (source, target, conversion) {
    this.source = source;
    this.target = target;
    this.locked = false;
    this.conversion = conversion;
};

nx.Binding.prototype.convert = function (value, oldValue) {
    if (typeof this.conversion !== 'undefined') {
        if (this.conversion instanceof nx.Mapping) {
            return this.conversion.map(value, this.target.value);
        } else if (typeof this.conversion === 'function') {
            return this.conversion(value, oldValue);
        }
    } else {
        return value;
    }
};

nx.Binding.prototype.sync = function (value, oldValue) {
    if (this.locked) {
        return;
    }
    var targets;
    if (typeof this.target === 'function') {
        targets = this.target(value, oldValue);
        if (Array.isArray(targets)) {
            targets.forEach(function (target) {
                target.value = this.convert(value, oldValue);
            }, this);
        } else {
            targets.value = this.convert(value, oldValue);
        }
    } else {
        this.target.value = this.convert(value, oldValue);
    }
};

nx.Binding.prototype.pair = function (binding) {
    this.twin = binding;
    binding.twin = this;
};

nx.Binding.prototype.lock = function () {
    this.locked = true;
};

nx.Binding.prototype.unlock = function () {
    this.locked = false;
};

nx.Binding.prototype.unbind = function () {
    delete this.source.bindings[this.index];
};

module.exports = nx.Binding;