import Quill from 'quill';

type SmartLinksOptions = {
    linkRegex: string;
};

export class SmartLinks {
    private regex: RegExp;

    constructor(quill: Quill, options: SmartLinksOptions) {
        const regexFormatMatch = options.linkRegex.match(/^\/(.+)\/([gimuy]*)$/);
        const pattern = regexFormatMatch ? regexFormatMatch[1] : options.linkRegex;
        const flags = regexFormatMatch ? regexFormatMatch[2] || 'i' : 'i';

        try {
            this.regex = new RegExp(pattern, flags);
        } catch (error) {
            console.error('Error with RegEx :', error);
            this.regex = new RegExp('');
            return;
        }

        quill.on('text-change', (delta) => this.handleTextChange(quill, delta));
    }

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

        const cursorIndex = selection.index;
        if (cursorIndex === null || cursorIndex === undefined) return;

        const [leaf] = quill.getLeaf(cursorIndex);
        if (!leaf) return;

        if (leaf.parent.domNode.localName === 'a') return;

        const value = leaf.value();
        if (!value || typeof value !== 'string') return;

        const insert = delta?.ops?.find(op => op.insert)?.insert;
        const specialKeyPressed = insert === '\n' || insert === '\t';

        const match = this.regex.exec(value);
        if (!match || !match[0]) return;

        const link = match[0];
        const substringIndex = match.index;
        const leafIndex = quill.getIndex(leaf);
        const startIndex = leafIndex + substringIndex;
        const endIndex = startIndex + link.length;

        if (!specialKeyPressed && cursorIndex <= endIndex && cursorIndex > startIndex) return;

        quill.deleteText(startIndex, link.length, 'api');
        quill.insertText(startIndex, link, 'link', link);
    }
}