/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.messaging.ui.conversation;

import android.app.FragmentManager;
import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.widget.EditText;

import com.android.messaging.R;
import com.android.messaging.datamodel.binding.BindingBase;
import com.android.messaging.datamodel.binding.ImmutableBindingRef;
import com.android.messaging.datamodel.data.ConversationData;
import com.android.messaging.datamodel.data.ConversationData.ConversationDataListener;
import com.android.messaging.datamodel.data.ConversationData.SimpleConversationDataListener;
import com.android.messaging.datamodel.data.DraftMessageData;
import com.android.messaging.datamodel.data.DraftMessageData.DraftMessageSubscriptionDataProvider;
import com.android.messaging.datamodel.data.MessagePartData;
import com.android.messaging.datamodel.data.PendingAttachmentData;
import com.android.messaging.datamodel.data.SubscriptionListData.SubscriptionListEntry;
import com.android.messaging.ui.ConversationDrawables;
import com.android.messaging.ui.mediapicker.MediaPicker;
import com.android.messaging.ui.mediapicker.MediaPicker.MediaPickerListener;
import com.android.messaging.util.Assert;
import com.android.messaging.util.ImeUtil;
import com.android.messaging.util.ImeUtil.ImeStateHost;
import com.google.common.annotations.VisibleForTesting;

import java.util.Collection;

/**
 * Manages showing/hiding/persisting different mutually exclusive UI components nested in
 * ConversationFragment that take user inputs, i.e. media picker, SIM selector and
 * IME keyboard (the IME keyboard is not owned by Bugle, but we try to model it the same way
 * as the other components).
 */
public class ConversationInputManager implements ConversationInput.ConversationInputBase {
    /**
     * The host component where all input components are contained. This is typically the
     * conversation fragment but may be mocked in test code.
     */
    public interface ConversationInputHost extends DraftMessageSubscriptionDataProvider {
        void invalidateActionBar();
        void setOptionsMenuVisibility(boolean visible);
        void dismissActionMode();
        void selectSim(SubscriptionListEntry subscriptionData);
        void onStartComposeMessage();
        SimSelectorView getSimSelectorView();
        MediaPicker createMediaPicker();
        void showHideSimSelector(boolean show);
        int getSimSelectorItemLayoutId();
    }

    /**
     * The "sink" component where all inputs components will direct the user inputs to. This is
     * typically the ComposeMessageView but may be mocked in test code.
     */
    public interface ConversationInputSink {
        void onMediaItemsSelected(Collection<MessagePartData> items);
        void onMediaItemsUnselected(MessagePartData item);
        void onPendingAttachmentAdded(PendingAttachmentData pendingItem);
        void resumeComposeMessage();
        EditText getComposeEditText();
        void setAccessibility(boolean enabled);
    }

    private final ConversationInputHost mHost;
    private final ConversationInputSink mSink;

    /** Dependencies injected from the host during construction */
    private final FragmentManager mFragmentManager;
    private final Context mContext;
    private final ImeStateHost mImeStateHost;
    private final ImmutableBindingRef<ConversationData> mConversationDataModel;
    private final ImmutableBindingRef<DraftMessageData> mDraftDataModel;

    private final ConversationInput[] mInputs;
    private final ConversationMediaPicker mMediaInput;
    private final ConversationSimSelector mSimInput;
    private final ConversationImeKeyboard mImeInput;
    private int mUpdateCount;

    private final ImeUtil.ImeStateObserver mImeStateObserver = new ImeUtil.ImeStateObserver() {
        @Override
        public void onImeStateChanged(final boolean imeOpen) {
            mImeInput.onVisibilityChanged(imeOpen);
        }
    };

    private final ConversationDataListener mDataListener = new SimpleConversationDataListener() {
        @Override
        public void onConversationParticipantDataLoaded(ConversationData data) {
            mConversationDataModel.ensureBound(data);
        }

        @Override
        public void onSubscriptionListDataLoaded(ConversationData data) {
            mConversationDataModel.ensureBound(data);
            mSimInput.onSubscriptionListDataLoaded(data.getSubscriptionListData());
        }
    };

    public ConversationInputManager(
            final Context context,
            final ConversationInputHost host,
            final ConversationInputSink sink,
            final ImeStateHost imeStateHost,
            final FragmentManager fm,
            final BindingBase<ConversationData> conversationDataModel,
            final BindingBase<DraftMessageData> draftDataModel,
            final Bundle savedState) {
        mHost = host;
        mSink = sink;
        mFragmentManager = fm;
        mContext = context;
        mImeStateHost = imeStateHost;
        mConversationDataModel = BindingBase.createBindingReference(conversationDataModel);
        mDraftDataModel = BindingBase.createBindingReference(draftDataModel);

        // Register listeners on dependencies.
        mImeStateHost.registerImeStateObserver(mImeStateObserver);
        mConversationDataModel.getData().addConversationDataListener(mDataListener);

        // Initialize the inputs
        mMediaInput = new ConversationMediaPicker(this);
        mSimInput = new SimSelector(this);
        mImeInput = new ConversationImeKeyboard(this, mImeStateHost.isImeOpen());
        mInputs = new ConversationInput[] { mMediaInput, mSimInput, mImeInput };

        if (savedState != null) {
            for (int i = 0; i < mInputs.length; i++) {
                mInputs[i].restoreState(savedState);
            }
        }
        updateHostOptionsMenu();
    }

    public void onDetach() {
        mImeStateHost.unregisterImeStateObserver(mImeStateObserver);
        // Don't need to explicitly unregister for data model events. It will unregister all
        // listeners automagically on unbind.
    }

    public void onSaveInputState(final Bundle savedState) {
        for (int i = 0; i < mInputs.length; i++) {
            mInputs[i].saveState(savedState);
        }
    }

    @Override
    public String getInputStateKey(final ConversationInput input) {
        return input.getClass().getCanonicalName() + "_savedstate_";
    }

    public boolean onBackPressed() {
        for (int i = 0; i < mInputs.length; i++) {
            if (mInputs[i].onBackPressed()) {
                return true;
            }
        }
        return false;
    }

    public boolean onNavigationUpPressed() {
        for (int i = 0; i < mInputs.length; i++) {
            if (mInputs[i].onNavigationUpPressed()) {
                return true;
            }
        }
        return false;
    }

    public void resetMediaPickerState() {
        mMediaInput.resetViewHolderState();
    }

    public void showHideMediaPicker(final boolean show, final boolean animate) {
        showHideInternal(mMediaInput, show, animate);
    }

    /**
     * Show or hide the sim selector
     * @param show visibility
     * @param animate whether to animate the change in visibility
     * @return true if the state of the visibility was changed
     */
    public boolean showHideSimSelector(final boolean show, final boolean animate) {
        return showHideInternal(mSimInput, show, animate);
    }

    public void showHideImeKeyboard(final boolean show, final boolean animate) {
        showHideInternal(mImeInput, show, animate);
    }

    public void hideAllInputs(final boolean animate) {
        beginUpdate();
        for (int i = 0; i < mInputs.length; i++) {
            showHideInternal(mInputs[i], false, animate);
        }
        endUpdate();
    }

    /**
     * Toggle the visibility of the sim selector.
     * @param animate
     * @param subEntry
     * @return true if the view is now shown, false if it now hidden
     */
    public boolean toggleSimSelector(final boolean animate, final SubscriptionListEntry subEntry) {
        mSimInput.setSelected(subEntry);
        return mSimInput.toggle(animate);
    }

    public boolean updateActionBar(final ActionBar actionBar) {
        for (int i = 0; i < mInputs.length; i++) {
            if (mInputs[i].mShowing) {
                return mInputs[i].updateActionBar(actionBar);
            }
        }
        return false;
    }

    @VisibleForTesting
    boolean isMediaPickerVisible() {
        return mMediaInput.mShowing;
    }

    @VisibleForTesting
    boolean isSimSelectorVisible() {
        return mSimInput.mShowing;
    }

    @VisibleForTesting
    boolean isImeKeyboardVisible() {
        return mImeInput.mShowing;
    }

    @VisibleForTesting
    void testNotifyImeStateChanged(final boolean imeOpen) {
        mImeStateObserver.onImeStateChanged(imeOpen);
    }

    /**
     * returns true if the state of the visibility was actually changed
     */
    @Override
    public boolean showHideInternal(final ConversationInput target, final boolean show,
            final boolean animate) {
        if (!mConversationDataModel.isBound()) {
            return false;
        }

        if (target.mShowing == show) {
            return false;
        }
        beginUpdate();
        boolean success;
        if (!show) {
            success = target.hide(animate);
        } else {
            success = target.show(animate);
        }

        if (success) {
            target.onVisibilityChanged(show);
        }
        endUpdate();
        return true;
    }

    @Override
    public void handleOnShow(final ConversationInput target) {
        if (!mConversationDataModel.isBound()) {
            return;
        }
        beginUpdate();

        // All inputs are mutually exclusive. Showing one will hide everything else.
        // The one exception, is that the keyboard and location media chooser can be open at the
        // time to enable searching within that chooser
        for (int i = 0; i < mInputs.length; i++) {
            final ConversationInput currInput = mInputs[i];
            if (currInput != target) {
                // TODO : If there's more exceptions we will want to make this more
                // generic
                if (currInput instanceof ConversationMediaPicker &&
                        target instanceof ConversationImeKeyboard &&
                        mMediaInput.getExistingOrCreateMediaPicker() != null &&
                        mMediaInput.getExistingOrCreateMediaPicker().canShowIme()) {
                    // Allow the keyboard and location mediaPicker to be open at the same time,
                    // but ensure the media picker is full screen to allow enough room
                    mMediaInput.getExistingOrCreateMediaPicker().setFullScreen(true);
                    continue;
                }
                showHideInternal(currInput, false /* show */, false /* animate */);
            }
        }
        // Always dismiss action mode on show.
        mHost.dismissActionMode();
        // Invoking any non-keyboard input UI is treated as starting message compose.
        if (target != mImeInput) {
            mHost.onStartComposeMessage();
        }
        endUpdate();
    }

    @Override
    public void beginUpdate() {
        mUpdateCount++;
    }

    @Override
    public void endUpdate() {
        Assert.isTrue(mUpdateCount > 0);
        if (--mUpdateCount == 0) {
            // Always try to update the host action bar after every update cycle.
            mHost.invalidateActionBar();
        }
    }

    private void updateHostOptionsMenu() {
        mHost.setOptionsMenuVisibility(!mMediaInput.isOpen());
    }

    /**
     * Manages showing/hiding the media picker in conversation.
     */
    private class ConversationMediaPicker extends ConversationInput {
        public ConversationMediaPicker(ConversationInputBase baseHost) {
            super(baseHost, false);
        }

        private MediaPicker mMediaPicker;

        @Override
        public boolean show(boolean animate) {
            if (mMediaPicker == null) {
                mMediaPicker = getExistingOrCreateMediaPicker();
                setConversationThemeColor(ConversationDrawables.get().getConversationThemeColor());
                mMediaPicker.setSubscriptionDataProvider(mHost);
                mMediaPicker.setDraftMessageDataModel(mDraftDataModel);
                mMediaPicker.setListener(new MediaPickerListener() {
                    @Override
                    public void onOpened() {
                        handleStateChange();
                    }

                    @Override
                    public void onFullScreenChanged(boolean fullScreen) {
                        // When we're full screen, we want to disable accessibility on the
                        // ComposeMessageView controls (attach button, message input, sim chooser)
                        // that are hiding underneath the action bar.
                        mSink.setAccessibility(!fullScreen /*enabled*/);
                        handleStateChange();
                    }

                    @Override
                    public void onDismissed() {
                        // Re-enable accessibility on all controls now that the media picker is
                        // going away.
                        mSink.setAccessibility(true /*enabled*/);
                        handleStateChange();
                    }

                    private void handleStateChange() {
                        onVisibilityChanged(isOpen());
                        mHost.invalidateActionBar();
                        updateHostOptionsMenu();
                    }

                    @Override
                    public void onItemsSelected(final Collection<MessagePartData> items,
                            final boolean resumeCompose) {
                        mSink.onMediaItemsSelected(items);
                        mHost.invalidateActionBar();
                        if (resumeCompose) {
                            mSink.resumeComposeMessage();
                        }
                    }

                    @Override
                    public void onItemUnselected(final MessagePartData item) {
                        mSink.onMediaItemsUnselected(item);
                        mHost.invalidateActionBar();
                    }

                    @Override
                    public void onConfirmItemSelection() {
                        mSink.resumeComposeMessage();
                    }

                    @Override
                    public void onPendingItemAdded(final PendingAttachmentData pendingItem) {
                        mSink.onPendingAttachmentAdded(pendingItem);
                    }

                    @Override
                    public void onChooserSelected(final int chooserIndex) {
                        mHost.invalidateActionBar();
                        mHost.dismissActionMode();
                    }
                });
            }

            mMediaPicker.open(MediaPicker.MEDIA_TYPE_DEFAULT, animate);

            return isOpen();
        }

        @Override
        public boolean hide(boolean animate) {
            if (mMediaPicker != null) {
                mMediaPicker.dismiss(animate);
            }
            return !isOpen();
        }

        public void resetViewHolderState() {
            if (mMediaPicker != null) {
                mMediaPicker.resetViewHolderState();
            }
        }

        public void setConversationThemeColor(final int themeColor) {
            if (mMediaPicker != null) {
                mMediaPicker.setConversationThemeColor(themeColor);
            }
        }

        private boolean isOpen() {
            return (mMediaPicker != null && mMediaPicker.isOpen());
        }

        private MediaPicker getExistingOrCreateMediaPicker() {
            if (mMediaPicker != null) {
                return mMediaPicker;
            }
            MediaPicker mediaPicker = (MediaPicker)
                    mFragmentManager.findFragmentByTag(MediaPicker.FRAGMENT_TAG);
            if (mediaPicker == null) {
                mediaPicker = mHost.createMediaPicker();
                if (mediaPicker == null) {
                    return null;    // this use of ComposeMessageView doesn't support media picking
                }
                mFragmentManager.beginTransaction().replace(
                        R.id.mediapicker_container,
                        mediaPicker,
                        MediaPicker.FRAGMENT_TAG).commit();
            }
            return mediaPicker;
        }

        @Override
        public boolean updateActionBar(ActionBar actionBar) {
            if (isOpen()) {
                mMediaPicker.updateActionBar(actionBar);
                return true;
            }
            return false;
        }

        @Override
        public boolean onNavigationUpPressed() {
            if (isOpen() && mMediaPicker.isFullScreen()) {
                return onBackPressed();
            }
            return super.onNavigationUpPressed();
        }

        public boolean onBackPressed() {
            if (mMediaPicker != null && mMediaPicker.onBackPressed()) {
                return true;
            }
            return super.onBackPressed();
        }
    }

    /**
     * Manages showing/hiding the SIM selector in conversation.
     */
    private class SimSelector extends ConversationSimSelector {
        public SimSelector(ConversationInputBase baseHost) {
            super(baseHost);
        }

        @Override
        protected SimSelectorView getSimSelectorView() {
            return mHost.getSimSelectorView();
        }

        @Override
        public int getSimSelectorItemLayoutId() {
            return mHost.getSimSelectorItemLayoutId();
        }

        @Override
        protected void selectSim(SubscriptionListEntry item) {
            mHost.selectSim(item);
        }

        @Override
        public boolean show(boolean animate) {
            final boolean result = super.show(animate);
            mHost.showHideSimSelector(true /*show*/);
            return result;
        }

        @Override
        public boolean hide(boolean animate) {
            final boolean result = super.hide(animate);
            mHost.showHideSimSelector(false /*show*/);
            return result;
        }
    }

    /**
     * Manages showing/hiding the IME keyboard in conversation.
     */
    private class ConversationImeKeyboard extends ConversationInput {
        public ConversationImeKeyboard(ConversationInputBase baseHost, final boolean isShowing) {
            super(baseHost, isShowing);
        }

        @Override
        public boolean show(boolean animate) {
            ImeUtil.get().showImeKeyboard(mContext, mSink.getComposeEditText());
            return true;
        }

        @Override
        public boolean hide(boolean animate) {
            ImeUtil.get().hideImeKeyboard(mContext, mSink.getComposeEditText());
            return true;
        }
    }
}