// Deterministic compiler/runtime/stdlib fuzzing through the WebAssembly host.
// Usage: node tests/drivers/fuzz_wasm.js path/to/zc.wasm
const fs = require('fs');
const ZC = require('../../src/web/zc.js');

let state = 0x5a17;
function next() { state = (Math.imul(state, 1664525) + 1013904223) >>> 0; return state; }
function expr(depth) {
	if (!depth || next() % 4 === 0) { const n = next() % 10; return [String(n), n]; }
	const [left, a] = expr(depth - 1), [right, b] = expr(depth - 1), op = ['+', '-', '*'][next() % 3];
	return [`(${left} ${op} ${right})`, op === '+' ? a + b : op === '-' ? a - b : a * b];
}
function quote(s) { return '"' + s + '"'; }

(async () => {
	const lines = ['namespace;', 'include rt, std;', 'fn churn(n) { int i = 0; while (i < n) { { int* p = rt.new(int); *p = i; } i++; } return 0; }', 'fn stable() { return 73; }', 'fn main() {', ' let base = rt.live_objects();'];
	const expected = [];
	for (let i = 0; i < 128; i++) {
		const [source, value] = expr(4);
		lines.push(` rt.put_n(${source}); rt.put_c(32);`); expected.push(value);
	}
	for (let i = 0; i < 32; i++) {
		const a = Array.from({ length: next() % 11 }, () => 'abc'[next() % 3]).join('');
		const b = Array.from({ length: next() % 6 }, () => 'abc'[next() % 3]).join('');
		lines.push(` rt.put_n(std.Text.len(${quote(a)})); rt.put_c(32); rt.put_n(std.Text.eq(${quote(a)}, ${quote(b)})); rt.put_c(32);`);
		lines.push(` rt.put_n(std.Text.starts(${quote(a)}, ${quote(b)})); rt.put_c(32); rt.put_n(std.Text.ends(${quote(a)}, ${quote(b)})); rt.put_c(32); rt.put_n(std.Text.find(${quote(a)}, ${quote(b)})); rt.put_c(32);`);
		lines.push(` rt.put_n(std.Bytes.len(b${quote(a)})); rt.put_c(32); rt.put_n(std.Bytes.eq(b${quote(a)}, b${quote(b)})); rt.put_c(32);`);
		lines.push(` rt.put_n(std.Bytes.starts(b${quote(a)}, b${quote(b)})); rt.put_c(32); rt.put_n(std.Bytes.ends(b${quote(a)}, b${quote(b)})); rt.put_c(32); rt.put_n(std.Bytes.find(b${quote(a)}, b${quote(b)})); rt.put_c(32);`);
		expected.push(a.length, Number(a === b), Number(a.startsWith(b)), Number(a.endsWith(b)), a.indexOf(b), a.length, Number(a === b), Number(a.startsWith(b)), Number(a.endsWith(b)), a.indexOf(b));
	}
	lines.push(' churn(300); rt.gc(); rt.put_n(rt.live_objects() - base); rt.put_c(32);', ' rt.put_n(stable()); rt.put_c(10);', ' return 0;', '}');
	expected.push(0, 73);
	const source = lines.join('\n') + '\n', want = expected.join(' ') + '\n';
	const zc = await ZC.load(fs.readFileSync(process.argv[2] || 'build/web/zc.wasm'));
	const result = await zc.run(source);
	if (result.output !== want) throw new Error(`wasm fuzz mismatch\nexpected: ${want.slice(0, 180)}\nactual: ${result.output.slice(0, 180)}\nmessages: ${result.messages}`);
	console.log('ok   wasm compiler/runtime/stdlib fuzz: 128 expressions, 300 scoped allocations and GC, and 32 Text/Bytes cases');
})().catch(error => { console.error(error); process.exitCode = 1; });