var DIRTY_PREFIX = '__dt__';

var Cache = function () {

    this._contextId = 0;

    this._caches = [];

    this._context = {};
};

Cache.prototype = {

    use: function (contextId, documentSchema) {
        var caches = this._caches;
        if (!caches[contextId]) {
            caches[contextId] = {};

            if (documentSchema) {
                caches[contextId] = documentSchema();
            }
        }
        this._contextId = contextId;

        this._context = caches[contextId];
    },

    put: function (key, value) {
        this._context[key] = value;
    },

    get: function (key) {
        return this._context[key];
    },

    dirty: function (field) {
        field = field || '';
        var key = DIRTY_PREFIX + field;
        this.put(key, true);
    },

    dirtyAll: function (field) {
        field = field || '';
        var key = DIRTY_PREFIX + field;
        var caches = this._caches;
        for (var i = 0; i < caches.length; i++) {
            if (caches[i]) {
                caches[i][key] = true;
            }
        }
    },

    fresh: function (field) {
        field = field || '';
        var key = DIRTY_PREFIX + field;
        this.put(key, false);
    },

    freshAll: function (field) {
        field = field || '';
        var key = DIRTY_PREFIX + field;
        var caches = this._caches;
        for (var i = 0; i < caches.length; i++) {
            if (caches[i]) {
                caches[i][key] = false;
            }
        }
    },

    isDirty: function (field) {
        field = field || '';
        var key = DIRTY_PREFIX + field;
        var context = this._context;
        return  !context.hasOwnProperty(key)
            || context[key] === true;
    },

    deleteContext: function (contextId) {
        delete this._caches[contextId];
        this._context = {};
    },

    delete: function (key) {
        delete this._context[key];
    },

    clearAll: function () {
        this._caches = {};
    },

    getContext: function () {
        return this._context;
    },

    eachContext : function (cb, context) {
        var keys = Object.keys(this._caches);
        keys.forEach(function (key) {
            cb && cb.call(context, key);
        });
    },

    miss: function (key) {
        return ! this._context.hasOwnProperty(key);
    }
};

Cache.prototype.constructor = Cache;

export default Cache;