package it.niedermann.owncloud.notes.util;

import android.content.Context;
import android.graphics.Color;
import android.text.Spanned;
import android.text.TextUtils;
import android.util.Log;

import androidx.annotation.NonNull;
import androidx.core.content.res.ResourcesCompat;

import com.yydcdut.markdown.MarkdownConfiguration;
import com.yydcdut.markdown.MarkdownConfiguration.Builder;
import com.yydcdut.markdown.MarkdownProcessor;
import com.yydcdut.markdown.span.MDImageSpan;
import com.yydcdut.markdown.theme.ThemeDefault;
import com.yydcdut.markdown.theme.ThemeSonsOfObsidian;

import it.niedermann.owncloud.notes.R;

/**
 * Created by stefan on 07.12.16.
 */

@SuppressWarnings("WeakerAccess")
public class MarkDownUtil {

    private static final String TAG = MarkDownUtil.class.getSimpleName();

    public static final String CHECKBOX_UNCHECKED_MINUS = "- [ ]";
    public static final String CHECKBOX_UNCHECKED_MINUS_TRAILING_SPACE = CHECKBOX_UNCHECKED_MINUS + " ";
    public static final String CHECKBOX_UNCHECKED_STAR = "* [ ]";
    public static final String CHECKBOX_UNCHECKED_STAR_TRAILING_SPACE = CHECKBOX_UNCHECKED_STAR + " ";
    public static final String CHECKBOX_CHECKED_MINUS = "- [x]";
    public static final String CHECKBOX_CHECKED_STAR = "* [x]";

    private static final String MD_IMAGE_WITH_EMPTY_DESCRIPTION = "![](";
    private static final String MD_IMAGE_WITH_SPACE_DESCRIPTION = "![ ](";
    private static final String[] MD_IMAGE_WITH_EMPTY_DESCRIPTION_ARRAY = new String[]{MD_IMAGE_WITH_EMPTY_DESCRIPTION};
    private static final String[] MD_IMAGE_WITH_SPACE_DESCRIPTION_ARRAY = new String[]{MD_IMAGE_WITH_SPACE_DESCRIPTION};

    /**
     * Ensures every instance of RxMD uses the same configuration
     *
     * @param context Context
     * @return RxMDConfiguration
     */
    public static Builder getMarkDownConfiguration(Context context) {
        return getMarkDownConfiguration(context, Notes.isDarkThemeActive(context));
    }

    public static Builder getMarkDownConfiguration(Context context, Boolean darkTheme) {
        return new MarkdownConfiguration.Builder(context)
                .setUnOrderListColor(ResourcesCompat.getColor(context.getResources(),
                        darkTheme ? R.color.widget_fg_dark_theme : R.color.widget_fg_default, null))
                .setHeader2RelativeSize(1.35f)
                .setHeader3RelativeSize(1.25f)
                .setHeader4RelativeSize(1.15f)
                .setHeader5RelativeSize(1.1f)
                .setHeader6RelativeSize(1.05f)
                .setHorizontalRulesHeight(2)
                .setCodeBgColor(darkTheme ? ResourcesCompat.getColor(context.getResources(), R.color.fg_default_high, null) : Color.LTGRAY)
                .setTheme(darkTheme ? new ThemeSonsOfObsidian() : new ThemeDefault())
                .setTodoColor(ResourcesCompat.getColor(context.getResources(),
                        darkTheme ? R.color.widget_fg_dark_theme : R.color.widget_fg_default, null))
                .setTodoDoneColor(ResourcesCompat.getColor(context.getResources(),
                        darkTheme ? R.color.widget_fg_dark_theme : R.color.widget_fg_default, null))
                .setLinkFontColor(ResourcesCompat.getColor(context.getResources(), R.color.defaultBrand, null))
                .setRxMDImageLoader(new NotesImageLoader(context))
                .setDefaultImageSize(400, 300);
    }

    /**
     * This is a compatibility-method that provides workarounds for several bugs in RxMarkdown
     * <p>
     * https://github.com/stefan-niedermann/nextcloud-notes/issues/772
     *
     * @param markdownProcessor RxMarkdown MarkdownProcessor instance
     * @param text              CharSequence that should be parsed
     * @return the processed text but with several workarounds for Bugs in RxMarkdown
     */
    @NonNull
    public static CharSequence parseCompat(@NonNull final MarkdownProcessor markdownProcessor, CharSequence text) {
        if (TextUtils.isEmpty(text)) {
            return "";
        }

        Log.v(TAG, "parseCompat - Original: \"" + text + "\"");

        while (TextUtils.indexOf(text, MD_IMAGE_WITH_EMPTY_DESCRIPTION) >= 0) {
            text = TextUtils.replace(text, MD_IMAGE_WITH_EMPTY_DESCRIPTION_ARRAY, MD_IMAGE_WITH_SPACE_DESCRIPTION_ARRAY);
        }

        Log.v(TAG, "parseCompat - Replaced empty image descriptions: \"" + text + "\"");

        return markdownProcessor.parse(text);
    }

    public static boolean containsImageSpan(@NonNull CharSequence text) {
        return ((Spanned) text).getSpans(0, text.length(), MDImageSpan.class).length > 0;
    }

    public static boolean lineStartsWithCheckbox(@NonNull String line) {
        return lineStartsWithCheckbox(line, true) || lineStartsWithCheckbox(line, false);
    }

    public static boolean lineStartsWithCheckbox(@NonNull String line, boolean starAsLeadingCharacter) {
        return starAsLeadingCharacter
                ? line.startsWith(CHECKBOX_UNCHECKED_STAR) || line.startsWith(CHECKBOX_CHECKED_STAR)
                : line.startsWith(CHECKBOX_UNCHECKED_MINUS) || line.startsWith(CHECKBOX_CHECKED_MINUS);
    }

    public static int getStartOfLine(@NonNull CharSequence s, int cursorPosition) {
        int startOfLine = cursorPosition;
        while (startOfLine > 0 && s.charAt(startOfLine - 1) != '\n') {
            startOfLine--;
        }
        return startOfLine;
    }

    public static int getEndOfLine(@NonNull CharSequence s, int cursorPosition) {
        int nextLinebreak = s.toString().indexOf('\n', cursorPosition);
        if (nextLinebreak > -1) {
            return nextLinebreak;
        }
        return cursorPosition;
    }
}