// TODO(jwall): Use RequireJS http://requirejs.org/docs/jquery.html
if (typeof dynamicbible == "undefined") {
    dynamicbible = {};
}

// dynamicbible.db implements a basic wrapper for IndexedDB databases.
// See http://www.w3.org/TR/IndexedDB/ for more details about the
// IDB* interfaces referenced below.
dynamicbible.db = {
    version: 1,
    dbName: "localdata",
    stores: ['settings', 'verselists'],
    debug: false,
    // Initialize database. If debug is true then logging will be turned on.
    Init: function(debug) {
        var self = this;
        self.debug = debug;
        self.Session(
            function(e) {
                self.debug && console.log("Database Init complete");
            });
        return self;
    },
    // Internal method not for external use.
    handleError: function(e) {
        this.debug && console.log("Error: ", e);
    },
    // Internal method not for external use.
    handleUpdate: function(e) {
        var db = e.target.result;
        e.target.transaction.onerror = this.handleError;
        for (i in this.stores) {
            if (db.objectStoreNames.contains(this.stores[i])) {
                // TODO(jwall): handle this more gracefully?
                db.deleteObjectStore(this.stores[i]);
            }
            var store = db.createObjectStore(this.stores[i],
                                             {keyPath: "key"});
        }
    },
    // Do operations on an open database.
    // ops is expected to be a function taking an IDBDatabase object
    // as a parameter.
    Session: function(ops) {
        var self = this;
        var req = indexedDB.open(this.dbname, this.version);
        // HandleUpgrades
        req.onupgradeneeded = function(e) {
          self.handleUpdate(e);
        };
        req.onsuccess = function(e) {
          ops(e.target.result);
        };
    },
    // Do operations on an open transaction scoped to the list of stores.
    // ops is expected to be a function taking an IDBTransation object
    // as a parameter.
    // type is an optional transaction type. values should be one of the
    // following: readonly or readwrite
    Transaction: function(stores, ops, type) {
        var self = this;
        var transType = type || "readonly";
        self.debug && console.log(
            "running", transType, "transaction on stores",
            stores);
        self.Session(
            function(db) {
                // Figure this api out.
                var trans = db.transaction(stores, transType);
                ops(trans);
            });
    },
    // Get a key from the the object store.
    // success is expected to be a function taking an IDBRequest object
    // as a parameter.
    // error is optional and expected to be a function taking an IDBRequest
    // object as a parameter.
    Get: function(storeName, key, success, error) {
        var self = this;
        self.Transaction(
            [storeName], function(trans) {
                var store = trans.objectStore(storeName);
                var req = store.get(key);
                req.onsuccess = success;
                req.onerror = error || self.handleError;
            });
    },
    // Store or update a key with data in an object store.
    // success is expected to be a function taking an IDBRequest object
    // as a parameter.
    // error is optional and expected to be a function taking an IDBRequest
    // object as a parameter.
    Update: function(storeName, key, data, success, error) {
        var self = this;
        self.Transaction(
            [storeName], function(trans) {
                var store = trans.objectStore(storeName);
                var req = store.put({"key": key, "data": data});
                req.onsuccess = success;
                req.onerror = error || self.handleError;
            }, "readwrite");
    },
    // Delete a key from an object store.
    // success is expected to be a function taking an IDBRequest object
    // as a parameter.
    // error is optional and expected to be a function taking an IDBRequest
    // object as a parameter.
    Delete: function(storeName, key, success, error) {
        var self = this;
        self.Transaction(
            [storeName], function(trans) {
                var store = trans.objectStore(storeName);
                var req = store.delete(key);
                req.onsuccess = success;
                req.onerror = error || self.handleError;
            }, "readwrite");
    },
    // Query a range of values from an object store.
    // range is expected to be an IDBKeyRange.
    // success is expected to be a function taking an IDBRequest object
    // as a parameter.
    // error is optional and expected to be a function taking an IDBRequest
    // object as a parameter.
    Query: function(storeName, range, success, error) {
        var self = this;
        self.Transaction(
            [storeName], function(trans) {
                var store = trans.objectStore(storeName);
                var req = store.openCursor(range);
                req.onsuccess = success;
                req.onerror = error || self.handleError;
            });
    }
};