package org.schabi.newpipe.util;

import android.content.Context;
import android.text.SpannableStringBuilder;
import android.text.method.LinkMovementMethod;
import android.text.style.ClickableSpan;
import android.text.style.URLSpan;
import android.text.util.Linkify;
import android.view.View;
import android.widget.TextView;

import androidx.core.text.HtmlCompat;

import io.noties.markwon.Markwon;
import io.noties.markwon.linkify.LinkifyPlugin;

public final class LinkHelper {
    private LinkHelper() {
    }

    /**
     * Create web links for contents with an HTML description.
     * <p>
     * This will call
     * {@link LinkHelper#changeIntentsOfDescriptionLinks(Context, CharSequence, TextView)}
     * after linked the URLs with {@link HtmlCompat#fromHtml(String, int)}.
     *
     * @param context        the context to use
     * @param htmlBlock      the htmlBlock to be linked
     * @param textView       the TextView to set the htmlBlock linked
     * @param htmlCompatFlag the int flag to be set when {@link HtmlCompat#fromHtml(String, int)}
     *                       will be called
     */
    public static void createLinksFromHtmlBlock(final Context context,
                                                final String htmlBlock,
                                                final TextView textView,
                                                final int htmlCompatFlag) {
        changeIntentsOfDescriptionLinks(context, HtmlCompat.fromHtml(htmlBlock, htmlCompatFlag),
                textView);
    }

    /**
     * Create web links for contents with a plain text description.
     * <p>
     * This will call
     * {@link LinkHelper#changeIntentsOfDescriptionLinks(Context, CharSequence, TextView)}
     * after linked the URLs with {@link TextView#setAutoLinkMask(int)} and
     * {@link TextView#setText(CharSequence, TextView.BufferType)}.
     *
     * @param context        the context to use
     * @param plainTextBlock the block of plain text to be linked
     * @param textView       the TextView to set the plain text block linked
     */
    public static void createLinksFromPlainText(final Context context,
                                                final String plainTextBlock,
                                                final TextView textView) {
        textView.setAutoLinkMask(Linkify.WEB_URLS);
        textView.setText(plainTextBlock, TextView.BufferType.SPANNABLE);
        changeIntentsOfDescriptionLinks(context, textView.getText(), textView);
    }

    /**
     * Create web links for contents with a markdown description.
     * <p>
     * This will call
     * {@link LinkHelper#changeIntentsOfDescriptionLinks(Context, CharSequence, TextView)}
     * after creating an {@link Markwon} object and using
     * {@link Markwon#setMarkdown(TextView, String)}.
     *
     * @param context       the context to use
     * @param markdownBlock the block of markdown text to be linked
     * @param textView      the TextView to set the plain text block linked
     */
    public static void createLinksFromMarkdownText(final Context context,
                                                   final String markdownBlock,
                                                   final TextView textView) {
        final Markwon markwon = Markwon.builder(context).usePlugin(LinkifyPlugin.create()).build();
        markwon.setMarkdown(textView, markdownBlock);
        changeIntentsOfDescriptionLinks(context, textView.getText(), textView);
    }

    /**
     * Change links generated by libraries in the description of a content to a custom link action.
     * <p>
     * Instead of using an ACTION_VIEW intent in the description of a content, this method will
     * parse the CharSequence and replace all current web links with
     * {@link ShareUtils#openUrlInBrowser(Context, String, Boolean)}.
     * <p>
     * This method is required in order to intercept links and maybe, show a confirmation dialog
     * before opening a web link.
     *
     * @param context  the context to use
     * @param chars    the CharSequence to be parsed
     * @param textView the TextView in which the converted CharSequence will be applied
     */
    private static void changeIntentsOfDescriptionLinks(final Context context,
                                                        final CharSequence chars,
                                                        final TextView textView) {
        final SpannableStringBuilder textBlockLinked = new SpannableStringBuilder(chars);
        final URLSpan[] urls = textBlockLinked.getSpans(0, chars.length(), URLSpan.class);

        for (final URLSpan span : urls) {
            final ClickableSpan clickableSpan = new ClickableSpan() {
                public void onClick(final View view) {
                    ShareUtils.openUrlInBrowser(context, span.getURL(), false);
                }
            };
            textBlockLinked.setSpan(clickableSpan, textBlockLinked.getSpanStart(span),
                    textBlockLinked.getSpanEnd(span), textBlockLinked.getSpanFlags(span));
            textBlockLinked.removeSpan(span);
        }

        textView.setText(textBlockLinked);
        textView.setMovementMethod(LinkMovementMethod.getInstance());
    }
}