import type Spec from './Spec';

import type Production from './Production';

import Builder from './Builder';

export default class RHS extends Builder {

/** @internal */ production: Production;

/** @internal */ constraints: string | null;

/** @internal */ alternativeId: string | null;

constructor(spec: Spec, prod: Production, node: HTMLElement) {

super(spec, node);

this.production = prod;

this.node = node;

this.constraints = node.getAttribute('constraints');

this.alternativeId = node.getAttribute('a');

}

build() {

if (this.node.textContent === '') {

this.node.textContent = '[empty]';

return;

}

if (this.constraints) {

const cs = this.spec.doc.createElement('emu-constraints');

cs.textContent = '[' + this.constraints + ']';

this.node.insertBefore(cs, this.node.childNodes[0]);

}

this.terminalify(this.node);

}

terminalify(parentNode: Element) {

// we store effects to perform later so the iteration doesn't get messed up

const surrogateTags = ['INS', 'DEL', 'MARK'];

const pairs: { parent: Element; child: Text }[] = [];

for (const node of parentNode.childNodes) {

if (node.nodeType === 3) {

pairs.push({ parent: parentNode, child: node as Text });

} else if (surrogateTags.includes(node.nodeName)) {

for (const child of node.childNodes) {

if (child.nodeType === 3) {

pairs.push({ parent: node as Element, child: child as Text });

}

}

}

}

let first = true;

for (const { parent, child } of pairs) {

if (!first && !/^\s+$/.test(child.textContent ?? '')) {

if (parent === parentNode) {

parentNode.insertBefore(this.spec.doc.createTextNode(' '), child);

} else {

// put the space outside of `<ins>` (etc) tags

parentNode.insertBefore(this.spec.doc.createTextNode(' '), parent);

}

}

first = false;

this.wrapTerminal(parent, child);

}

}

private wrapTerminal(parentNode: Element, node: Text) {

const textContent = node.textContent!;

const text = textContent.trim();

if (text === '' && textContent.length > 0) {

// preserve intermediate whitespace

return;

}

const pieces = text.split(/\s/);

let first = true;

pieces.forEach(p => {

if (p.length === 0) {

return;

}

const est = this.spec.doc.createElement('emu-t');

est.textContent = p;

parentNode.insertBefore(est, node);

if (!first) {

parentNode.insertBefore(this.spec.doc.createTextNode(' '), est);

}

first = false;

});

parentNode.removeChild(node);

}

}