/*
 * Copyright (C) 2013 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.terminal;

import static com.android.terminal.Terminal.TAG;

import android.content.Context;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;
import android.graphics.Typeface;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.inputmethod.BaseInputConnection;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.widget.BaseAdapter;
import android.widget.ListView;

import com.android.terminal.Terminal.CellRun;
import com.android.terminal.Terminal.TerminalClient;

/**
 * Rendered contents of a {@link Terminal} session.
 */
public class TerminalView extends ListView {
    private static final boolean LOGD = true;

    private static final boolean SCROLL_ON_DAMAGE = false;
    private static final boolean SCROLL_ON_INPUT = true;

    private Terminal mTerm;

    private boolean mScrolled;

    private int mRows;
    private int mCols;
    private int mScrollRows;

    private final TerminalMetrics mMetrics = new TerminalMetrics();
    private final TerminalKeys mTermKeys = new TerminalKeys();

    /**
     * Metrics shared between all {@link TerminalLineView} children. Locking
     * provided by main thread.
     */
    static class TerminalMetrics {
        private static final int MAX_RUN_LENGTH = 128;

        final Paint bgPaint = new Paint();
        final Paint textPaint = new Paint();

        /** Run of cells used when drawing */
        final CellRun run;
        /** Screen coordinates to draw chars into */
        final float[] pos;

        int charTop;
        int charWidth;
        int charHeight;

        public TerminalMetrics() {
            run = new Terminal.CellRun();
            run.data = new char[MAX_RUN_LENGTH];

            // Positions of each possible cell
            // TODO: make sure this works with surrogate pairs
            pos = new float[MAX_RUN_LENGTH * 2];
            setTextSize(20);
        }

        public void setTextSize(float textSize) {
            textPaint.setTypeface(Typeface.MONOSPACE);
            textPaint.setAntiAlias(true);
            textPaint.setTextSize(textSize);

            // Read metrics to get exact pixel dimensions
            final FontMetrics fm = textPaint.getFontMetrics();
            charTop = (int) Math.ceil(fm.top);

            final float[] widths = new float[1];
            textPaint.getTextWidths("X", widths);
            charWidth = (int) Math.ceil(widths[0]);
            charHeight = (int) Math.ceil(fm.descent - fm.top);

            // Update drawing positions
            for (int i = 0; i < MAX_RUN_LENGTH; i++) {
                pos[i * 2] = i * charWidth;
                pos[(i * 2) + 1] = -charTop;
            }
        }
    }

    private final Runnable mDamageRunnable = new Runnable() {
        @Override
        public void run() {
            invalidateViews();
            if (SCROLL_ON_DAMAGE) {
                scrollToBottom(true);
            }
        }
    };

    public TerminalView(Context context) {
        this(context, null);
    }

    public TerminalView(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.listViewStyle);
    }

    public TerminalView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        setBackground(null);
        setDivider(null);

        setFocusable(true);
        setFocusableInTouchMode(true);

        setAdapter(mAdapter);
        setOnKeyListener(mKeyListener);
    }

    private final BaseAdapter mAdapter = new BaseAdapter() {
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            final TerminalLineView view;
            if (convertView != null) {
                view = (TerminalLineView) convertView;
            } else {
                view = new TerminalLineView(parent.getContext(), mTerm, mMetrics);
            }

            view.pos = position;
            view.row = posToRow(position);
            view.cols = mCols;
            return view;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public int getCount() {
            if (mTerm != null) {
                return mRows + mScrollRows;
            } else {
                return 0;
            }
        }
    };

    private TerminalClient mClient = new TerminalClient() {
        @Override
        public void onDamage(final int startRow, final int endRow, int startCol, int endCol) {
            post(mDamageRunnable);
        }

        @Override
        public void onMoveRect(int destStartRow, int destEndRow, int destStartCol, int destEndCol,
                int srcStartRow, int srcEndRow, int srcStartCol, int srcEndCol) {
            post(mDamageRunnable);
        }

        @Override
        public void onBell() {
            Log.i(TAG, "DING!");
        }
    };

    private int rowToPos(int row) {
        return row + mScrollRows;
    }

    private int posToRow(int pos) {
        return pos - mScrollRows;
    }

    private View.OnKeyListener mKeyListener = new OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            final boolean res = mTermKeys.onKey(v, keyCode, event);
            if (res && SCROLL_ON_INPUT) {
                scrollToBottom(true);
            }
            return res;
        }
    };

    @Override
    public void onRestoreInstanceState(Parcelable state) {
        super.onRestoreInstanceState(state);
        mScrolled = true;
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (!mScrolled) {
            scrollToBottom(false);
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);

        final int rows = h / mMetrics.charHeight;
        final int cols = w / mMetrics.charWidth;
        final int scrollRows = mScrollRows;

        final boolean sizeChanged = (rows != mRows || cols != mCols || scrollRows != mScrollRows);
        if (mTerm != null && sizeChanged) {
            mTerm.resize(rows, cols, scrollRows);

            mRows = rows;
            mCols = cols;
            mScrollRows = scrollRows;

            mAdapter.notifyDataSetChanged();
        }
    }

    public void scrollToBottom(boolean animate) {
        final int dur = animate ? 250 : 0;
        smoothScrollToPositionFromTop(getCount(), 0, dur);
        mScrolled = true;
    }

    public void setTerminal(Terminal term) {
        final Terminal orig = mTerm;
        if (orig != null) {
            orig.setClient(null);
        }
        mTerm = term;
        mScrolled = false;
        if (term != null) {
            term.setClient(mClient);
            mTermKeys.setTerminal(term);

            // Populate any current settings
            mRows = mTerm.getRows();
            mCols = mTerm.getCols();
            mScrollRows = mTerm.getScrollRows();
            mAdapter.notifyDataSetChanged();
        }
    }

    public Terminal getTerminal() {
        return mTerm;
    }

    public void setTextSize(float textSize) {
        mMetrics.setTextSize(textSize);

        // Layout will kick off terminal resize when needed
        requestLayout();
    }

    @Override
    public boolean onCheckIsTextEditor() {
        return true;
    }

    @Override
    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
        outAttrs.imeOptions |=
            EditorInfo.IME_FLAG_NO_EXTRACT_UI |
            EditorInfo.IME_FLAG_NO_ENTER_ACTION |
            EditorInfo.IME_ACTION_NONE;
        outAttrs.inputType = EditorInfo.TYPE_NULL;
        return new BaseInputConnection(this, false) {
            @Override
            public boolean deleteSurroundingText (int leftLength, int rightLength) {
                KeyEvent k;
                if (rightLength == 0 && leftLength == 0) {
                    k = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL);
                    return this.sendKeyEvent(k);
                }
                for (int i = 0; i < leftLength; i++) {
                    k = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL);
                    this.sendKeyEvent(k);
                }
                for (int i = 0; i < rightLength; i++) {
                    k = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_FORWARD_DEL);
                    this.sendKeyEvent(k);
                }
                return true;
            }
        };
    }
}