package eu.siacs.conversations.ui.widget;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.text.Editable;
import android.text.InputFilter;
import android.text.InputType;
import android.text.Spannable;
import android.text.Spanned;
import android.text.SpannableStringBuilder;
import android.text.TextWatcher;
import android.text.style.ImageSpan;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;

import androidx.appcompat.widget.AppCompatEditText;
import androidx.core.view.inputmethod.EditorInfoCompat;
import androidx.core.view.inputmethod.InputConnectionCompat;
import androidx.core.view.inputmethod.InputContentInfoCompat;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import eu.siacs.conversations.Config;
import eu.siacs.conversations.R;
import eu.siacs.conversations.ui.util.QuoteHelper;

public class EditMessage extends AppCompatEditText {

    private static final InputFilter SPAN_FILTER = (source, start, end, dest, dstart, dend) -> source instanceof Spanned ? source.toString() : source;
    private final ExecutorService executor = Executors.newSingleThreadExecutor();
    protected Handler mTypingHandler = new Handler();
    protected KeyboardListener keyboardListener;
    private OnCommitContentListener mCommitContentListener = null;
    private String[] mimeTypes = null;
    private boolean isUserTyping = false;
    private final Runnable mTypingTimeout = new Runnable() {
        @Override
        public void run() {
            if (isUserTyping && keyboardListener != null) {
                keyboardListener.onTypingStopped();
                isUserTyping = false;
            }
        }
    };
    private boolean lastInputWasTab = false;

    public EditMessage(Context context, AttributeSet attrs) {
        super(context, attrs);
        addTextChangedListener(new Watcher());
    }

    public EditMessage(Context context) {
        super(context);
        addTextChangedListener(new Watcher());
    }

    @Override
    public boolean onKeyDown(final int keyCode, final KeyEvent e) {
        final boolean isCtrlPressed = e.isCtrlPressed();
        if (keyCode == KeyEvent.KEYCODE_ENTER && !e.isShiftPressed()) {
            lastInputWasTab = false;
            if (keyboardListener != null && keyboardListener.onEnterPressed(isCtrlPressed)) {
                return true;
            }
        } else if (keyCode == KeyEvent.KEYCODE_TAB && !e.isAltPressed() && !isCtrlPressed) {
            if (keyboardListener != null && keyboardListener.onTabPressed(this.lastInputWasTab)) {
                lastInputWasTab = true;
                return true;
            }
        } else {
            lastInputWasTab = false;
        }
        return super.onKeyDown(keyCode, e);
    }

    @Override
    public int getAutofillType() {
        return AUTOFILL_TYPE_NONE;
    }

    @Override
    public void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        lastInputWasTab = false;
        if (this.mTypingHandler != null && this.keyboardListener != null) {
            executor.execute(() -> triggerKeyboardEvents(text.length()));
        }
    }

    private void triggerKeyboardEvents(final int length) {
        final KeyboardListener listener = this.keyboardListener;
        if (listener == null) {
            return;
        }
        this.mTypingHandler.removeCallbacks(mTypingTimeout);
        this.mTypingHandler.postDelayed(mTypingTimeout, Config.TYPING_TIMEOUT * 1000);
        if (!isUserTyping && length > 0) {
            this.isUserTyping = true;
            listener.onTypingStarted();
        } else if (length == 0) {
            this.isUserTyping = false;
            listener.onTextDeleted();
        }
        listener.onTextChanged();
    }

    public void setKeyboardListener(KeyboardListener listener) {
        this.keyboardListener = listener;
        if (listener != null) {
            this.isUserTyping = false;
        }
    }

    @Override
    public boolean onTextContextMenuItem(int id) {
        if (id == android.R.id.paste) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                return super.onTextContextMenuItem(android.R.id.pasteAsPlainText);
            } else {
                Editable editable = getEditableText();
                InputFilter[] filters = editable.getFilters();
                InputFilter[] tempFilters = new InputFilter[filters != null ? filters.length + 1 : 1];
                if (filters != null) {
                    System.arraycopy(filters, 0, tempFilters, 1, filters.length);
                }
                tempFilters[0] = SPAN_FILTER;
                editable.setFilters(tempFilters);
                try {
                    return super.onTextContextMenuItem(id);
                } finally {
                    editable.setFilters(filters);
                }
            }
        } else {
            return super.onTextContextMenuItem(id);
        }
    }

    public void setRichContentListener(String[] mimeTypes, OnCommitContentListener listener) {
        this.mimeTypes = mimeTypes;
        this.mCommitContentListener = listener;
    }

    public void insertAsQuote(String text) {
        text = QuoteHelper.quote(text);
        Editable editable = getEditableText();
        int position = getSelectionEnd();
        if (position == -1) position = editable.length();
        if (position > 0 && editable.charAt(position - 1) != '\n') {
            editable.insert(position++, "\n");
        }
        editable.insert(position, text);
        position += text.length();
        editable.insert(position++, "\n");
        if (position < editable.length() && editable.charAt(position) != '\n') {
            editable.insert(position, "\n");
        }
        setSelection(position);
    }

    @Override
    public InputConnection onCreateInputConnection(EditorInfo editorInfo) {
        final InputConnection ic = super.onCreateInputConnection(editorInfo);

        if (mimeTypes != null && mCommitContentListener != null && ic != null) {
            EditorInfoCompat.setContentMimeTypes(editorInfo, mimeTypes);
            return InputConnectionCompat.createWrapper(ic, editorInfo, (inputContentInfo, flags, opts) -> EditMessage.this.mCommitContentListener.onCommitContent(inputContentInfo, flags, opts, mimeTypes));
        } else {
            return ic;
        }
    }

    public void refreshIme() {
        SharedPreferences p = PreferenceManager.getDefaultSharedPreferences(getContext());
        final boolean usingEnterKey = p.getBoolean("display_enter_key", getResources().getBoolean(R.bool.display_enter_key));
        final boolean enterIsSend = p.getBoolean("enter_is_send", getResources().getBoolean(R.bool.enter_is_send));

        if (usingEnterKey && enterIsSend) {
            setInputType(getInputType() & (~InputType.TYPE_TEXT_FLAG_MULTI_LINE));
            setInputType(getInputType() & (~InputType.TYPE_TEXT_VARIATION_SHORT_MESSAGE));
        } else if (usingEnterKey) {
            setInputType(getInputType() | InputType.TYPE_TEXT_FLAG_MULTI_LINE);
            setInputType(getInputType() & (~InputType.TYPE_TEXT_VARIATION_SHORT_MESSAGE));
        } else {
            setInputType(getInputType() | InputType.TYPE_TEXT_FLAG_MULTI_LINE);
            setInputType(getInputType() | InputType.TYPE_TEXT_VARIATION_SHORT_MESSAGE);
        }
    }

    public interface OnCommitContentListener {
        boolean onCommitContent(InputContentInfoCompat inputContentInfo, int flags, Bundle opts, String[] mimeTypes);
    }

    public interface KeyboardListener {
        boolean onEnterPressed(boolean isCtrlPressed);

        void onTypingStarted();

        void onTypingStopped();

        void onTextDeleted();

        void onTextChanged();

        boolean onTabPressed(boolean repeated);
    }

    public static class Watcher implements TextWatcher {
        protected List<ImageSpan> spansToRemove = new ArrayList<>();

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (s instanceof SpannableStringBuilder && ((SpannableStringBuilder) s).getTextWatcherDepth() > 1) return;
            }

            if (!(s instanceof Spannable)) return;
            Spannable text = (Spannable) s;

            if (count > 0 && text != null) { // something deleted
                int end = start + count;
                ImageSpan[] spans = text.getSpans(start, end, ImageSpan.class);
                synchronized(spansToRemove) {
                    for (ImageSpan span : spans) {
                        if (text.getSpanStart(span) < end && start < text.getSpanEnd(span)) {
                            spansToRemove.add(span);
                        }
                    }
                }
            }
        }

        @Override
        public void afterTextChanged(Editable s) {
            List<ImageSpan> toRemove;
            synchronized(spansToRemove) {
                toRemove = new ArrayList<>(spansToRemove);
                spansToRemove.clear();
            }
            for (ImageSpan span : toRemove) {
                if (s.getSpanStart(span) > -1 && s.getSpanEnd(span) > -1) {
                    s.removeSpan(span);
                }
            }
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int count, int after) { }
    }
}