// stattest — exercises [[os.stat]] / [[os.lstat]] / [[os.fstat]] /
// [[os.exists]] against a scratch tree pre-arranged by
// test/wcc/976_stat_run.c. The driver mkdtemp's a tmp dir, creates a
// regfile + symlink + subdir, exports paths through env vars, then
// exec's `ww run lib/os/stattest.ww`. We read the paths back via
// os.getenv and stat the targets.
//
// Pre-arranged scratch tree (set by 976_stat_run.c):
//
//   WW_TEST_STAT_REGFILE  = "<tmp>/regfile"   regular file, 11 bytes
//   WW_TEST_STAT_SYMLINK  = "<tmp>/symlink"   symlink → ./regfile
//   WW_TEST_STAT_SUBDIR   = "<tmp>/subdir"    directory, 0700
//   WW_TEST_STAT_NOENT    = "<tmp>/does-not-exist"
//
// Test exit code follows the stdlib `_run` convention: a `signalled`
// global the main fn bumps before each row, so `WEXITSTATUS = signalled
// + 10` tells the harness which row tripped. Same shape as
// ostest / temptest / shlextest.

package os;

import os;

let signalled: i32 = 0;

fn fail() void = { os.exit(signalled + 10); };

// envpath — fetch an env var or abort; we want a clean signal if
// 976_stat_run.c didn't prime the env state.
fn envpath(name: str) str = {
	match (os.getenv(name)) {
	case void => { fail(); return "": str; };
	case let s: str => return s;
	};
};

// 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);
};

// ---- stat: regular file --------------------------------------------
//
// Pinned bytes are "hello world" (11 bytes). We verify:
//   - mask is fully set (newfstatat fills everything)
//   - mode's type bits == REG
//   - sz == 11
//   - inode is non-zero (real fs entry, not synthetic)

@test fn test_stat_regfile() void = {
	let p = envpath("WW_TEST_STAT_REGFILE");
	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, p)) {
	case let e: os.oserror => fail();
	case void => {
		if ((fi.mask as u32) != wantmask) { fail(); };
		if (!istype(fi.mode, os.mode.REG)) { fail(); };
		if (fi.sz != 11u64) { fail(); };
		if (fi.inode == 0u64) { fail(); };
		// Permission-bit smoke test — 976_stat_run.c 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) {
			fail();
		};
		// 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.
		if (fi.atime.sec <= 0i64) { fail(); };
		if (fi.mtime.sec <= 0i64) { fail(); };
		if (fi.ctime.sec <= 0i64) { fail(); };
	};
	};
};

// ---- stat: directory ------------------------------------------------

@test fn test_stat_subdir() void = {
	let p = envpath("WW_TEST_STAT_SUBDIR");
	let fi: os.filestat;
	match (os.stat(&fi, p)) {
	case let e: os.oserror => fail();
	case void => {
		if (!istype(fi.mode, os.mode.DIR)) { fail(); };
	};
	};
};

// ---- stat: missing path → oserror ENOENT ---------------------------

@test fn test_stat_noent() void = {
	let p = envpath("WW_TEST_STAT_NOENT");
	let fi: os.filestat;
	match (os.stat(&fi, p)) {
	case void => fail();
	case let e: os.oserror => {
		// ENOENT = 2 → raw errno is -2.
		if ((e: i64) != -2i64) { fail(); };
	};
	};
};

// ---- stat (follow) vs lstat (no-follow) on a symlink ----------------
//
// stat follows the link → reports the regfile (REG, 11 bytes).
// lstat does NOT follow → reports the link itself (LINK).

@test fn test_stat_symlink_follow() void = {
	let p = envpath("WW_TEST_STAT_SYMLINK");
	let fi: os.filestat;
	match (os.stat(&fi, p)) {
	case let e: os.oserror => fail();
	case void => {
		if (!istype(fi.mode, os.mode.REG)) { fail(); };
		if (fi.sz != 11u64) { fail(); };
	};
	};
};

@test fn test_lstat_symlink_nofollow() void = {
	let p = envpath("WW_TEST_STAT_SYMLINK");
	let fi: os.filestat;
	match (os.lstat(&fi, p)) {
	case let e: os.oserror => fail();
	case void => {
		if (!istype(fi.mode, os.mode.LINK)) { fail(); };
	};
	};
};

// ---- fstat: open a file and stat by fd ------------------------------

@test fn test_fstat_regfile() void = {
	let p = envpath("WW_TEST_STAT_REGFILE");
	let fd: i32 = os.open(p, os.flag.RDONLY, 0i32);
	if (fd < 0) { fail(); };
	let fi: os.filestat;
	match (os.fstat(&fi, fd)) {
	case let e: os.oserror => { os.close(fd); fail(); };
	case void => {
		if (!istype(fi.mode, os.mode.REG)) { os.close(fd); fail(); };
		if (fi.sz != 11u64) { os.close(fd); fail(); };
	};
	};
	os.close(fd);
};

// ---- exists: true on regfile/dir/symlink, false on noent ------------

@test fn test_exists_regfile() void = {
	let p = envpath("WW_TEST_STAT_REGFILE");
	if (!os.exists(p)) { fail(); };
};

@test fn test_exists_subdir() void = {
	let p = envpath("WW_TEST_STAT_SUBDIR");
	if (!os.exists(p)) { fail(); };
};

@test fn test_exists_noent() void = {
	let p = envpath("WW_TEST_STAT_NOENT");
	if (os.exists(p)) { fail(); };
};

// ---- ENAMETOOLONG: kpath rejects paths >= PATH_MAX -------------------
//
// 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 => fail();
	case let e: os.oserror => {
		if ((e: i64) != -36i64) { fail(); };	// ENAMETOOLONG
	};
	};
};

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

export fn main() i32 = {
	signalled = 1; test_stat_regfile();
	signalled = 2; test_stat_subdir();
	signalled = 3; test_stat_noent();
	signalled = 4; test_stat_symlink_follow();
	signalled = 5; test_lstat_symlink_nofollow();
	signalled = 6; test_fstat_regfile();
	signalled = 7; test_exists_regfile();
	signalled = 8; test_exists_subdir();
	signalled = 9; test_exists_noent();
	signalled = 10; test_stat_toolong();
	signalled = 11; test_exists_toolong();
	return 0;
};