import { ZWS } from '../Constants';
import { getPreviousBlock } from '../node/Block';
import { isInline, isBlock } from '../node/Category';
import { fixCursor } from '../node/MergeSplit';
import { createElement, detach, getNearest } from '../node/Node';
import { moveRangeBoundariesDownTree } from '../range/Boundaries';

import type { Squire } from '../Editor';

// ---

// If you delete the content inside a span with a font styling, Webkit will
// replace it with a <font> tag (!). If you delete all the text inside a
// link in Opera, it won't delete the link. Let's make things consistent. If
// you delete all text inside an inline tag, remove the inline tag.
const afterDelete = (self: Squire, range?: Range): void => {
    try {
        if (!range) {
            range = self.getSelection();
        }
        let node = range!.startContainer;
        // Climb the tree from the focus point while we are inside an empty
        // inline element
        if (node instanceof Text) {
            node = node.parentNode!;
        }
        let parent = node;
        while (
            isInline(parent) &&
            (!parent.textContent || parent.textContent === ZWS)
        ) {
            node = parent;
            parent = node.parentNode!;
        }
        // If focused in empty inline element
        if (node !== parent) {
            // Move focus to just before empty inline(s)
            range!.setStart(
                parent,
                Array.from(parent.childNodes as NodeListOf<Node>).indexOf(node),
            );
            range!.collapse(true);
            // Remove empty inline(s)
            parent.removeChild(node);
            // Fix cursor in block
            if (!isBlock(parent)) {
                parent = getPreviousBlock(parent, self._root) || self._root;
            }
            fixCursor(parent);
            // Move cursor into text node
            moveRangeBoundariesDownTree(range!);
        }
        // If you delete the last character in the sole <div> in Chrome,
        // it removes the div and replaces it with just a <br> inside the
        // root. Detach the <br>; the _ensureBottomLine call will insert a new
        // block.
        if (
            node === self._root &&
            (node = node.firstChild!) &&
            node.nodeName === 'BR'
        ) {
            detach(node);
        }
        self._ensureBottomLine();
        self.setSelection(range);
        self._updatePath(range, true);
    } catch (error) {
        self._config.didError(error);
    }
};

const detachUneditableNode = (node: Node, root: Element): void => {
    let parent: Node | null;
    while ((parent = node.parentNode)) {
        if (parent === root || (parent as HTMLElement).isContentEditable) {
            break;
        }
        node = parent;
    }
    detach(node);
};

// ---

const linkifyText = (self: Squire, textNode: Text, offset: number): void => {
    if (getNearest(textNode, self._root, 'A')) {
        return;
    }
    const data = textNode.data || '';
    const searchFrom =
        Math.max(
            data.lastIndexOf(' ', offset - 1),
            data.lastIndexOf(' ', offset - 1),
        ) + 1;
    const searchText = data.slice(searchFrom, offset);
    const match = self.linkRegExp.exec(searchText);
    if (match) {
        // Record an undo point
        const selection = self.getSelection();
        self._docWasChanged();
        self._recordUndoState(selection);
        self._getRangeAndRemoveBookmark(selection);

        const index = searchFrom + match.index;
        const endIndex = index + match[0].length;
        const needsSelectionUpdate = selection.startContainer === textNode;
        const newSelectionOffset = selection.startOffset - endIndex;
        if (index) {
            textNode = textNode.splitText(index);
        }

        const defaultAttributes = self._config.tagAttributes.a;
        const link = createElement(
            'A',
            Object.assign(
                {
                    href: match[1]
                        ? /^(?:ht|f)tps?:/i.test(match[1])
                            ? match[1]
                            : 'http://' + match[1]
                        : 'mailto:' + match[0],
                },
                defaultAttributes,
            ),
        );
        link.textContent = data.slice(index, endIndex);
        textNode.parentNode!.insertBefore(link, textNode);
        textNode.data = data.slice(endIndex);

        if (needsSelectionUpdate) {
            selection.setStart(textNode, newSelectionOffset);
            selection.setEnd(textNode, newSelectionOffset);
        }
        self.setSelection(selection);
    }
};

// ---

export { afterDelete, detachUneditableNode, linkifyText };