// Each row arranges its own scratch tree under [[temp.dir]] (Hare's
// own idiom: os tests self-arrange in a temp dir), so the suite
// passes bare with no external driver:
//
//   <root>/regfile          regular file, 11 bytes "hello world", 0644
//   <root>/symlink       →  ./regfile  (relative symlink)
//   <root>/subdir           directory, mode 0700
//   <root>/does-not-exist   guaranteed absent
//
// Trees are per-row because the runner forks one child per test —
// module state arranged in one row never reaches the next. Each row
// removes exactly what it created; a cleanup miss is a row failure
// (doubles as a layout assertion: the stat calls created nothing).
//
// A failing row aborts via the assert/abort builtin (task #5 @test
// conversion); the failure path deliberately leaves the tree for
// inspection (no defer in ww).

package os_test;

import os;
import strings;
import temp;



type tree = struct {
	root: str,
	regfile: str,
	symlink: str,
	subdir: str,
	noent: str,
};

fn mktree(t: *tree) void = {
	// temp.dir returns a view of temp's static pathbuf; dup before
	// deriving children so later temp calls can't clobber it.
	t.root = strings.dup(temp.dir());
	t.regfile = strings.concat(t.root, "/regfile");
	t.symlink = strings.concat(t.root, "/symlink");
	t.subdir = strings.concat(t.root, "/subdir");
	t.noent = strings.concat(t.root, "/does-not-exist");
	let fd: i32 = os.open(t.regfile,
	    os.flag.WRONLY | os.flag.CREATE | os.flag.EXCL, 420i32);	// 0o644
	assert(!(fd < 0));
	match (os.writeall(fd, "hello world".ptr, 11u64)) {
	case let n: i64 => assert(!(n != 11i64));
	case let e: os.oserror => abort();
	};
	assert(!(os.close(fd) != 0));
	assert(!(os.symlink("./regfile", t.symlink) != 0));
	assert(!(os.mkdir(t.subdir, 448i32) != 0));	// 0o700
};

fn rmtree(t: *tree) void = {
	assert(!(os.remove(t.symlink) != 0));
	assert(!(os.remove(t.regfile) != 0));
	assert(!(os.rmdir(t.subdir) != 0));
	assert(!(os.rmdir(t.root) != 0));
};

// istype — mask the file-type bits (S_IFMT = 0o170000 = 61440)
// out of a mode and compare against the requested type bit.
fn istype(m: os.mode, t: os.mode) bool = {
	return ((m as u32) & 61440u32) == (t as u32);
};

@test fn test_stat_regfile() void = {
	let t: tree;
	mktree(&t);
	let fi: os.filestat;
	// newfstatat populates every field, so the mask is the
	// OR-fold of all 7 Hare stat_mask bits — mirrors what
	// fillfilestat assigns.
	let wantmask: u32 = (os.stat_mask.UID | os.stat_mask.GID
	    | os.stat_mask.SIZE | os.stat_mask.INODE
	    | os.stat_mask.ATIME | os.stat_mask.MTIME
	    | os.stat_mask.CTIME) as u32;
	match (os.stat(&fi, t.regfile)) {
	case let e: os.oserror => abort();
	case void => {
		assert(!((fi.mask as u32) != wantmask));
		assert(!(!istype(fi.mode, os.mode.REG)));
		assert(!(fi.sz != 11u64));
		assert(!(fi.inode == 0u64));
		// Permission-bit smoke test — mktree open(2)s with mode
		// 0644 so USER_R survives any reasonable umask. Catches
		// a struct-field-offset miscompile on `fi.mode` that the
		// type-bit istype() check could miss if perm bits aliased a
		// neighbouring u32 (uid/gid).
		if (((fi.mode as u32) & (os.mode.USER_R as u32)) == 0u32) {
			abort();
		};
		// atime/mtime/ctime — kernel-set at create time, all
		// post-epoch (>0). Three distinct kstat offsets (72/88/104)
		// so a fillfilestat field-copy miscompile or a filestat
		// time.instant offset bug surfaces here, not silently.
		assert(!(fi.atime.sec <= 0i64));
		assert(!(fi.mtime.sec <= 0i64));
		assert(!(fi.ctime.sec <= 0i64));
	};
	};
	rmtree(&t);
};

@test fn test_stat_subdir() void = {
	let t: tree;
	mktree(&t);
	let fi: os.filestat;
	match (os.stat(&fi, t.subdir)) {
	case let e: os.oserror => abort();
	case void => {
		assert(!(!istype(fi.mode, os.mode.DIR)));
	};
	};
	rmtree(&t);
};

@test fn test_stat_noent() void = {
	let t: tree;
	mktree(&t);
	let fi: os.filestat;
	match (os.stat(&fi, t.noent)) {
	case void => abort();
	case let e: os.oserror => {
		// ENOENT = 2 → raw errno is -2.
		assert(!((e: i64) != -2i64));
	};
	};
	rmtree(&t);
};

@test fn test_stat_symlink_follow() void = {
	let t: tree;
	mktree(&t);
	let fi: os.filestat;
	match (os.stat(&fi, t.symlink)) {
	case let e: os.oserror => abort();
	case void => {
		assert(!(!istype(fi.mode, os.mode.REG)));
		assert(!(fi.sz != 11u64));
	};
	};
	rmtree(&t);
};

@test fn test_lstat_symlink_nofollow() void = {
	let t: tree;
	mktree(&t);
	let fi: os.filestat;
	match (os.lstat(&fi, t.symlink)) {
	case let e: os.oserror => abort();
	case void => {
		assert(!(!istype(fi.mode, os.mode.LINK)));
	};
	};
	rmtree(&t);
};

@test fn test_readlink_verbatim() void = {
	let t: tree;
	mktree(&t);
	let buf: [16]u8;
	let i: i32 = 0;
	for (i < 16) { buf[i] = 90u8; i += 1; };	// 'Z'
	let n: i64 = os.readlink(t.symlink, &buf[0], 16u64);
	assert(!(n != 9i64));
	let want: str = "./regfile";
	i = 0;
	for (i < want.len) {
		assert(!(buf[i] != want[i]));
		i += 1;
	};
	let ni: i32 = n: i32;
	assert(!(buf[ni] != 90u8));
	rmtree(&t);
};

@test fn test_fstat_regfile() void = {
	let t: tree;
	mktree(&t);
	let fd: i32 = os.open(t.regfile, os.flag.RDONLY, 0i32);
	assert(!(fd < 0));
	let fi: os.filestat;
	match (os.fstat(&fi, fd)) {
	case let e: os.oserror => { os.close(fd); abort(); };
	case void => {
		if (!istype(fi.mode, os.mode.REG)) { os.close(fd); abort(); };
		if (fi.sz != 11u64) { os.close(fd); abort(); };
	};
	};
	os.close(fd);
	rmtree(&t);
};

@test fn test_exists_regfile() void = {
	let t: tree;
	mktree(&t);
	assert(!(!os.exists(t.regfile)));
	rmtree(&t);
};

@test fn test_exists_subdir() void = {
	let t: tree;
	mktree(&t);
	assert(!(!os.exists(t.subdir)));
	rmtree(&t);
};

@test fn test_exists_noent() void = {
	let t: tree;
	mktree(&t);
	assert(!(os.exists(t.noent)));
	rmtree(&t);
};

// kpath copies into a single [PATH_MAX]u8 buffer and reserves one byte
// for the NUL terminator (`p.len + 1 > PATH_MAX` → reject). The
// rejection surfaces as `oserror = -36` (ENAMETOOLONG) on (... |
// oserror)-returning wrappers, and as `false` on [[os.exists]]
// (Hare's os::exists doc: "true if a node exists at the given path,
// or false if not.").

let bigbuf: [4200]u8;

fn makebig(n: i32) str = {
	let i: i32 = 0;
	for (i < n) { bigbuf[i] = 97u8; i += 1; };	// 'a'
	let r: str;
	r.ptr = &bigbuf[0];
	r.len = n;
	return r;
};

@test fn test_stat_toolong() void = {
	let bp = makebig(os.PATH_MAX);
	let fi: os.filestat;
	match (os.stat(&fi, bp)) {
	case void => abort();
	case let e: os.oserror => {
		assert(!((e: i64) != -36i64));	// ENAMETOOLONG
	};
	};
};

@test fn test_exists_toolong() void = {
	let bp = makebig(os.PATH_MAX);
	assert(!(os.exists(bp)));
};