/**
 * WebkitSQLiteAdaptor
 * ===================
 * Sqlite implementation for Lawnchair.
 *
 */
var WebkitSQLiteAdaptor = function(options) {
    for (var i in LawnchairAdaptorHelpers) {
        this[i] = LawnchairAdaptorHelpers[i];
    }
    this.init(options);
};


WebkitSQLiteAdaptor.prototype = {
    init:function(options) {
        var that = this;
        var merge = that.merge;
        var opts = (typeof arguments[0] == 'string') ? {table:options} : options;

        // default properties
        this.name       = merge('Lawnchair', opts.name      );
        this.version    = merge('1.0',       opts.version   );
        this.table      = merge('field',     opts.table     );
        this.display    = merge('shed',      opts.display   );
        this.max        = merge(65536,       opts.max       );
        this.db         = merge(null,        opts.db        );

        // default sqlite callbacks
        this.onError = function(){};
        this.onData  = function(){};

        if("onError" in opts) {
            this.onError = opts.onError;
        }

        // error out on shit browsers
        if (!window.openDatabase)
            throw('Lawnchair, "This browser does not support sqlite storage."');

        // instantiate the store
        this.db = openDatabase(this.name, this.version, this.display, this.max);

        // create a default database and table if one does not exist
        this.db.transaction(function(tx) {
            tx.executeSql("SELECT COUNT(*) FROM " + that.table, [], function(){}, function(tx, error) {
                that.db.transaction(function(tx) {
                    tx.executeSql("CREATE TABLE "+ that.table + " (id NVARCHAR(32) UNIQUE PRIMARY KEY, value TEXT, timestamp REAL)", [], function(){}, that.onError);
                });
            });
        });
    },
    save:function(obj, callback) {
        var that = this;

        var update = function(id, obj, callback) {
            that.db.transaction(function(t) {
                t.executeSql(
                    "UPDATE " + that.table + " SET value=?, timestamp=? WHERE id=?",
                    [that.serialize(obj), that.now(), id],
                    function() {
                        if (callback != undefined) {
                            obj.key = id;
                            callback(obj);
                        }
                    },
                    that.onError
                );
            });
        };
        var insert = function(obj, callback) {
            that.db.transaction(function(t) {
                var id = (obj.key == undefined) ? that.uuid() : obj.key;
                delete(obj.key);
                t.executeSql(
                    "INSERT INTO " + that.table + " (id, value,timestamp) VALUES (?,?,?)",
                    [id, that.serialize(obj), that.now()],
                    function() {
                        if (callback != undefined) {
                            obj.key = id;
                            callback(obj);
                        }
                    },
                    that.onError
                );
            });
        };
        if (obj.key == undefined) {
            insert(obj, callback);
        } else {
            this.get(obj.key, function(r) {
                var isUpdate = (r != null);

                if (isUpdate) {
                    var id = obj.key;
                    delete(obj.key);
                    update(id, obj, callback);
                } else {
                    insert(obj, callback);
                }
            });
        }
    },
    get:function(key, callback) {
        var that = this;
        this.db.transaction(function(t) {
            t.executeSql(
                "SELECT value FROM " + that.table + " WHERE id = ?",
                [key],
                function(tx, results) {
                    if (results.rows.length == 0) {
                        callback(null);
                    } else {
                        var o = that.deserialize(results.rows.item(0).value);
                        o.key = key;
                        callback(o);
                    }
                },
                this.onError
            );
        });
    },
    all:function(callback) {
        var cb = this.terseToVerboseCallback(callback);
        var that = this;
        this.db.transaction(function(t) {
            t.executeSql("SELECT * FROM " + that.table, [], function(tx, results) {
                if (results.rows.length == 0 ) {
                    cb([]);
                } else {
                    var r = [];
                    for (var i = 0, l = results.rows.length; i < l; i++) {
                        var raw = results.rows.item(i).value;
                        var obj = that.deserialize(raw);
                        obj.key = results.rows.item(i).id;
                        r.push(obj);
                    }
                    cb(r);
                }
            },
            that.onError);
        });
    },
    remove:function(keyOrObj, callback) {
        var that = this;
        this.db.transaction(function(t) {
            t.executeSql(
                "DELETE FROM " + that.table + " WHERE id = ?",
                [(typeof keyOrObj == 'string') ? keyOrObj : keyOrObj.key],
                callback || that.onData,
                that.onError
            );
        });
    },
    nuke:function(callback) {
        var that = this;
        this.db.transaction(function(tx) {
            tx.executeSql(
                "DELETE FROM " + that.table,
                [],
                callback || that.onData,
                that.onError
            );
        });
    }
};