import idb from 'idb';

var dbPromise = idb.open('test-db', 4, function (upgradeDb) {

    switch (upgradeDb.oldVersion) {

        case 0:

            // keyval store is already created at version 1

            var keyValStore = upgradeDb.createObjectStore('keyval');

            keyValStore.put("world", "hello");

        case 1:

            // new version

            upgradeDb.createObjectStore('people', {keyPath: 'name'});

        case 2:

            var peopleStore = upgradeDb.transaction.objectStore('people');

            peopleStore.createIndex('animal', 'favoriteAnimal');

        case 3:

            var peopleStore = upgradeDb.transaction.objectStore('people');

            peopleStore.createIndex('age', 'age');

    }

});

// read "hello" in "keyval"

dbPromise.then(function (db) {

    var tx = db.transaction('keyval'); // Open a transaction

    var keyValStore = tx.objectStore('keyval'); // read the store

    return keyValStore.get('hello'); // get value by key

}).then(function (val) {

    console.log('The value of "hello" is:', val);

});

dbPromise.then(function (db) {

    var tx = db.transaction('people', 'readwrite');

    var peopleStore = tx.objectStore('people');

    peopleStore.put({

        name: "John", // name is the key

        age: 23,

        favoriteAnimal: 'cat'

    });

    peopleStore.put({

        name: "Joe", // name is the key

        age: 21,

        favoriteAnimal: 'cat'

    });

    peopleStore.put({

        name: "Jie", // name is the key

        age: 22,

        favoriteAnimal: 'dog'

    });

    peopleStore.put({

        name: "Jay", // name is the key

        age: 24,

        favoriteAnimal: 'dog'

    });

    return tx.complete;

}).then(function () {

    console.log("People are added");

});

dbPromise.then(function (db) {

    var tx = db.transaction('people', 'readwrite');

    var peopleStore = tx.objectStore('people');

    var ageIndex = peopleStore.index('age');

    return ageIndex.openCursor();

}).then(function (cursor) {

    if (!cursor) return;

    return cursor.advance(1); // skip the first person

}).then(function logPerson(cursor) {

    if(cursor.value.name == "Jie"){

        cursor.delete(); // delete

    }

    if(cursor.value.name == "Jay"){

        console.log("Cursor at:", cursor.value.name);

        var joe = cursor.value;

        joe.favoriteAnimal = "Bird";

        cursor.update(joe); // update

    }

    return cursor.continue().then(logPerson);

}).then(function () {

    console.log("DONE");

});