// errnotest — exercises [[errors.errno]] and the [[errors.opaque_]]
// tail. Run with `out/bin/ww run lib/errors/errnotest.ww`.
//
// Parallel `[N]T` arrays of (errno, expected-tag) rather than a
// `[N]struct{...}` table — the cstage cgen's chained `arr[i].field`
// store gap (task #6). [[errtag]] collapses each named-void variant to
// a small int so the row body is a single integer compare.

package errors_test;

import errors;
import os;

// signalled — bumped by main before each test so a failing exit code
// pinpoints the offending case.
let signalled: i32 = 0;
fn fail() void = { os.exit(signalled + 10); };

fn streq(a: str, b: str) bool = {
	if (a.len != b.len) { return false; };
	let i: i32 = 0;
	for (i < a.len) {
		if (a[i] != b[i]) { return false; };
		i += 1;
	};
	return true;
};

// errtag — the union discriminant as a stable int. opaque_ is 99 so a
// misrouted named condition can't masquerade as the unmapped tail.
fn errtag(e: errors.error) int = {
	match (e) {
	case errors.busy           => return 1;
	case errors.exists         => return 2;
	case errors.invalid        => return 3;
	case errors.noaccess       => return 4;
	case errors.noentry        => return 5;
	case errors.overflow       => return 6;
	case errors.unsupported    => return 7;
	case errors.timeout        => return 8;
	case errors.cancelled      => return 9;
	case errors.refused        => return 10;
	case errors.interrupted    => return 11;
	case errors.again          => return 12;
	case errors.netunreachable => return 13;
	case let o: errors.opaque_ => return 99;
	};
};

// ---- errno → named condition --------------------------------------
@test fn mapping() void = {
	let ins: [12]os.errno;
	ins[0]  = os.ECONNREFUSED;
	ins[1]  = os.ECANCELED;
	ins[2]  = os.EOVERFLOW;
	ins[3]  = os.EACCES;
	ins[4]  = os.EINVAL;
	ins[5]  = os.EEXIST;
	ins[6]  = os.ENOENT;
	ins[7]  = os.ETIMEDOUT;
	ins[8]  = os.EBUSY;
	ins[9]  = os.EINTR;
	ins[10] = os.EAGAIN;
	ins[11] = os.ENETUNREACH;

	let exp: [12]int;
	exp[0]  = 10;	// refused
	exp[1]  = 9;	// cancelled
	exp[2]  = 6;	// overflow
	exp[3]  = 4;	// noaccess
	exp[4]  = 3;	// invalid
	exp[5]  = 2;	// exists
	exp[6]  = 5;	// noentry
	exp[7]  = 8;	// timeout
	exp[8]  = 1;	// busy
	exp[9]  = 11;	// interrupted
	exp[10] = 12;	// again
	exp[11] = 13;	// netunreachable

	let i: i32 = 0;
	for (i < 12) {
		// store-to-local, not inline errtag(errors.errno(ins[i])): the
		// inline form hits #222 (large >4-eightbyte union sret-arg
		// clobber, cs==ww). store-then-consume is the idiomatic shape
		// regardless — it is how errno is actually used (cf
		// lib/io/stream.ww:53, and Hare's errors/rt.ha callers).
		let er: errors.error = errors.errno(ins[i]);
		if (errtag(er) != exp[i]) { fail(); };
		i += 1;
	};
};

// ---- unmapped errno → opaque_ tail --------------------------------
@test fn opaquetail() void = {
	// EIO (5) is outside the mapped set, so it wraps opaque_.
	let e: errors.error = errors.errno(5);
	if (errtag(e) != 99) { fail(); };
	match (e) {
	case let o: errors.opaque_ =>
		if (!streq((*o.strerror)(&o.data), "Unknown error")) { fail(); };
	case =>
		fail();
	};
};

// ---- os.strerror mapped path --------------------------------------
@test fn strerrortext() void = {
	if (!streq(os.strerror(os.ENOENT), "No such file or directory")) { fail(); };
	if (!streq(os.strerror(os.EINVAL), "Invalid argument")) { fail(); };
	if (!streq(os.strerror(5), "Unknown error")) { fail(); };
};

export fn main() i32 = {
	signalled = 1; mapping();
	signalled = 2; opaquetail();
	signalled = 3; strerrortext();
	return 0;
};