import Quill from 'quill';

export class Markdown {
    constructor(quill: Quill) {
        quill.on('text-change', (delta, oldDelta, source) => {
            if (source !== 'user') return;
            const insert = delta?.ops?.find(op => op.insert)?.insert;
            if (insert === ' ' || insert === '\n') {
                this.handleTextChange(quill);
            }
        });
    }

    private handleTextChange(quill: Quill): void {
        const selection = quill.getSelection();
        if (!selection) return;

        const index = selection.index;
        const [line, offset] = quill.getLine(index);
        if (!line) return;

        const lineIndex = quill.getIndex(line);
        const textBefore = line.domNode.innerText.substring(0, offset - 1);

        // Header
        const headerMatch = textBefore.match(/^(#{1,6})$/);
        if (headerMatch) {
            const level = headerMatch[1].length;
            quill.deleteText(lineIndex, level + 1, 'user');
            quill.formatLine(lineIndex, 1, 'header', level, 'user');
            return;
        }

        // Lists
        if (textBefore === '*' || textBefore === '-') {
            quill.deleteText(lineIndex, 2, 'user');
            quill.formatLine(lineIndex, 1, 'list', 'bullet', 'user');
            return;
        }

        if (textBefore === '1.') {
            quill.deleteText(lineIndex, 3, 'user');
            quill.formatLine(lineIndex, 1, 'list', 'ordered', 'user');
            return;
        }

        if (textBefore === '>') {
            quill.deleteText(lineIndex, 2, 'user');
            quill.formatLine(lineIndex, 1, 'blockquote', true, 'user');
            return;
        }
    }
}