// Copyright 2016 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package io.v.todos;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.VisibleForTesting;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

import java.util.List;

import io.v.todos.model.DataList;
import io.v.todos.model.ListMetadata;
import io.v.todos.model.ListSpec;
import io.v.todos.persistence.ListEventListener;
import io.v.todos.persistence.MainPersistence;
import io.v.todos.persistence.PersistenceFactory;

/**
 * MainActivity for Vanadium TODOs
 *
 * This activity shows a list of todo lists.
 * - Tap on a Todo List to launch its corresponding TodoListActivity.
 * - Swipe Left on a Todo List to delete it.
 * - Swipe Right in order to mark all of its Tasks as done.
 *
 * @author alexfandrianto
 */
public class MainActivity extends TodosAppActivity<MainPersistence, TodoListRecyclerAdapter> {
    // Snackoos are the code name for the list of todos.
    // These todos are backed up at the SNACKOOS child of the Firebase URL.
    // We use mMainList to track a custom sorted list of the stored values.
    static final String INTENT_SNACKOO_KEY = "snackoo key";
    private DataList<ListMetadata> mMainList = new DataList<>();

    private RecyclerView mRecyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getActionBar().setTitle(R.string.app_name);
        mEmptyView.setText(R.string.no_lists);

        // Set up the todo list adapter
        mAdapter = new TodoListRecyclerAdapter(mMainList, new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String fbKey = (String)view.getTag();

                Intent intent = new Intent(MainActivity.this, TodoListActivity.class);
                intent.putExtra(INTENT_SNACKOO_KEY, fbKey);
                startActivity(intent);
            }
        });

        mRecyclerView = (RecyclerView)findViewById(R.id.recycler);
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.setHasFixedSize(true);

        new ItemTouchHelper(new SwipeableTouchHelperCallback() {
            @Override
            public void onSwiped(final RecyclerView.ViewHolder viewHolder, final int direction) {
                String todoListKey = (String)viewHolder.itemView.getTag();
                if (direction == ItemTouchHelper.RIGHT) {
                    int position = mMainList.findIndexByKey(todoListKey);
                    if (position == -1) {
                        return;
                    }
                    ListMetadata l = mMainList.get(position);
                    if (l.canCompleteAll()) {
                        mPersistence.setCompletion(l, true);
                    } else if (l.numTasks > 0) {
                        mPersistence.setCompletion(l, false);
                    } else {
                        mAdapter.notifyItemChanged(position);
                    }
                } else if (direction == ItemTouchHelper.LEFT) {
                    mPersistence.deleteTodoList(todoListKey);
                }
            }
        }).attachToRecyclerView(mRecyclerView);

        new PersistenceInitializer<MainPersistence>(this) {
            @Override
            protected MainPersistence initPersistence() throws Exception {
                return PersistenceFactory.getMainPersistence(mActivity, createMainListener());
            }

            @Override
            protected void onSuccess(MainPersistence persistence) {
                mPersistence = persistence;
                setEmptyVisiblity();
            }
        }.execute(PersistenceFactory.mightGetMainPersistenceBlock());
    }

    // Creates a listener for this activity. Visible to tests to allow them to invoke the listener
    // methods directly.
    @VisibleForTesting
    ListEventListener<ListMetadata> createMainListener() {
        return new ListEventListener<ListMetadata>() {
            @Override
            public void onItemAdd(ListMetadata item) {
                int position = mMainList.insertInOrder(item);

                mAdapter.notifyItemInserted(position);
                setEmptyVisiblity();
            }

            @Override
            public void onItemUpdate(final ListMetadata item) {
                int start = mMainList.findIndexByKey(item.key);
                int end = mMainList.updateInOrder(item);

                if (start != end) {
                    mAdapter.notifyItemMoved(start, end);
                }

                // The change animation involves a cross-fade that, if interrupted
                // while another for the same item is already in progress, interacts
                // badly with ItemTouchHelper's swipe animator. The effect would be
                // a flicker of the intermediate ListMetadata view, then it fading
                // out to the latest view but X-translated off the screen due to the
                // swipe animator.
                //
                // We could queue up the next change after the current one, but it's
                // probably better just to rebind.
                TodoListViewHolder vh = (TodoListViewHolder) mRecyclerView
                        .findViewHolderForAdapterPosition(end);
                if (vh.itemView.getAlpha() < 1) {
                    mAdapter.bindViewHolder(vh, end);
                } else {
                    mAdapter.notifyItemChanged(end);
                }
            }

            @Override
            public void onItemDelete(String key) {
                int position = mMainList.removeByKey(key);

                mAdapter.notifyItemRemoved(position);
                setEmptyVisiblity();
            }
        };
    }

    public void initiateItemAdd(View view) {
        UIUtil.showAddDialog(this, "New Todo List", new UIUtil.DialogResponseListener() {
            @Override
            public void handleResponse(String response) {
                mPersistence.addTodoList(new ListSpec(response));
            }
        });
    }

    // The following methods are boilerplate for handling the Menu in the top right corner.
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}