// Port of cmd/w6c/main.c.

package main;

import os;
import rt;
import strings;
import syntax;
import wcc;

fn cstreq(a: *u8, lit: str) bool = {
	let n: u64 = lit.len: u64;
	let i: u64 = 0u64;
	for (i < n) {
		let li: i32 = i: i32;
		if (a[i] != lit[li]) { return false; };
		i += 1u64;
	};
	if (a[i] != 0u8) { return false; };
	return true;
};

fn cstrlen(p: *u8) u64 = {
	let n: u64 = 0u64;
	for (p[n] != 0u8) { n += 1u64; };
	return n;
};

// pathstr — view a NUL-terminated *u8 as a str. lib/os entrypoints
// take str post-task-#23; this bridges call sites that still hold
// C-string paths (argv entries, arena-allocated buffers).
fn pathstr(p: *u8) str = {
	let r: str;
	r.ptr = p;
	r.len = cstrlen(p): i32;
	return r;
};

fn slurp(path: *u8) (*u8, u64) = {
	let fd: i32 = os.open(pathstr(path), os.flag.RDONLY, 0i32);
	if (fd < 0) { return nil, 0u64; };
	let szr: (i64 | os.oserror) = os.filesize(fd);
	let n: i64 = 0i64;
	match (szr) {
	case let v: i64 => n = v;
	case let e: os.oserror => { os.close(fd); return nil, 0u64; };
	};
	let nz: u64 = n: u64;
	let buf: []u8 = alloc([], nz + 1u64)!;
	buf.len = (nz + 1u64): i32;
	let rr: (i64 | os.oserror) = os.readall(fd, buf.ptr, nz);
	os.close(fd);
	let got: i64 = 0i64;
	match (rr) {
	case let v: i64 => got = v;
	case let e: os.oserror => return nil, 0u64;
	};
	if (got != n) { return nil, 0u64; };
	buf[nz] = 0u8;
	return buf.ptr, nz;
};

export fn main(argc: i32, argv: **u8) i32 = {
	let src: *u8 = nil;
	let out: *u8 = nil;
	let wwiout: *u8 = nil;		// -I <out.wwi>: M2 export-data producer
	let testsupport: *u8 = nil;
	let testmode: i32 = 0i32;	// #15: `-T` test-mode
	let sepmode: i32 = 0i32;	// -c: #22 M3 separate-compile / primary-
					// only codegen (emit imported==0 decls
					// only; treat `.wwi` deps as external)
	let importpaths: []*u8 = alloc([], argc: u64)!;
	importpaths.len = argc;
	let importfiles: []*u8 = alloc([], argc: u64)!;
	importfiles.len = argc;
	let nimports: i32 = 0;

	let i: i32 = 1;
	for (i < argc) {
		let a: *u8 = argv[i];
		if (cstreq(a, "-o")) {
			i += 1;
			if (i >= argc) {
				let m: str = "w6c: -o requires arg\n";
				os.write(2, m.ptr, m.len: u64);
				return 2;
			};
			out = argv[i];
		} else { if (cstreq(a, "-I")) {
			i += 1;
			if (i >= argc) {
				let m: str = "w6c: -I requires arg\n";
				os.write(2, m.ptr, m.len: u64);
				return 2;
			};
			wwiout = argv[i];
		} else { if (cstreq(a, "-T")) {
			testmode = 1i32;
		} else { if (cstreq(a, "--test-support-module")) {
			i += 1;
			if (i >= argc) {
				let m: str = "w6c: --test-support-module requires arg\n";
				os.write(2, m.ptr, m.len: u64);
				return 2;
			};
			testsupport = argv[i];
		} else { if (cstreq(a, "-c")) {
			sepmode = 1i32;
		} else { if (cstreq(a, "--import")) {
			if (i + 2 >= argc) {
				let m: str = "w6c: --import requires path and file\n";
				os.write(2, m.ptr, m.len: u64);
				return 2;
			};
			importpaths[nimports] = argv[i + 1];
			importfiles[nimports] = argv[i + 2];
			nimports += 1;
			i += 2;
		} else { if (a[0u64] == 45u8) {
			let m: str = "w6c: unknown flag\n";
			os.write(2, m.ptr, m.len: u64);
			return 2;
		} else {
			if (src != nil) {
				let m: str = "w6c: only one input\n";
				os.write(2, m.ptr, m.len: u64);
				return 2;
			};
			src = a;
		}; }; }; }; }; }; };
		i += 1;
	};

	if (src == nil) {
		let m: str = "usage: w6c_ww [-T] [-c] [-I out.wwi] [--import path dep.wwi]... [-o out.s] file.ww\n";
		os.write(2, m.ptr, m.len: u64);
		return 2;
	};
	if (nimports > 0 && sepmode == 0) {
		let m: str = "w6c: --import requires -c\n";
		os.write(2, m.ptr, m.len: u64);
		return 2;
	};
	let importi: i32 = 0;
	for (importi < nimports) {
		if (importpaths[importi][0u64] == 0u8) {
			let m: str = "w6c: --import path is empty\n";
			os.write(2, m.ptr, m.len: u64);
			return 2;
		};
		if (importi > 0 && strings.compare(pathstr(importpaths[importi - 1]),
		    pathstr(importpaths[importi])) >= 0) {
			let m: str = "w6c: --import paths must be sorted and unique\n";
			os.write(2, m.ptr, m.len: u64);
			return 2;
		};
		importi += 1;
	};
	if (testsupport != nil && (sepmode == 0
		|| (!cstreq(testsupport, "test")
			&& !cstreq(testsupport, "__wwtest")))) {
		let m: str = "w6c: invalid --test-support-module\n";
		os.write(2, m.ptr, m.len: u64);
		return 2;
	};

	let importhead: *node = nil;
	let importtail: *node = nil;
	importi = 0;
	for (importi < nimports) {
		let ibuf: *u8;
		let ilen: u64;
		ibuf, ilen = slurp(importfiles[importi]);
		if (ibuf == nil) {
			let pre: str = "w6c: import ";
			let mid: str = ": cannot read ";
			let nl: str = "\n";
			let ipath: str = pathstr(importpaths[importi]);
			let ifile: str = pathstr(importfiles[importi]);
			os.write(2, pre.ptr, pre.len: u64);
			os.write(2, ipath.ptr, ipath.len: u64);
			os.write(2, mid.ptr, mid.len: u64);
			os.write(2, ifile.ptr, ifile.len: u64);
			os.write(2, nl.ptr, nl.len: u64);
			return 1;
		};
		let il: lex;
		lexinit(&il, strings.dup(pathstr(importfiles[importi])), ibuf, ilen);
		let ips: parser;
		parserinit(&ips, &il);
		let imod: str = pathstr(importpaths[importi]);
		ips.pathmod = imod;
		ips.curmod = imod;
		if (testsupport != nil) { ips.testmodule = pathstr(testsupport); };
		let imported: *node = parsefile(&ips);
		if (il.errs > 0 || ips.errs > 0) { return 1; };
		let d: *node = imported.list;
		if (d != nil) {
			if (importhead == nil) { importhead = d; }
			else { importtail.next = d; };
			for (d.next != nil) { d = d.next; };
			importtail = d;
		};
		importi += 1;
	};

	let buf: *u8;
	let blen: u64;
	buf, blen = slurp(src);
	if (buf == nil) {
		let m: str = "w6c: cannot read input\n";
		os.write(2, m.ptr, m.len: u64);
		return 1;
	};
	let l: lex;
	lexinit(&l, strings.dup(pathstr(src)), buf, blen);
	let ps: parser;
	parserinit(&ps, &l);
	if (testsupport != nil) { ps.testmodule = pathstr(testsupport); };
	let f: *node = parsefile(&ps);
	// Gate cgen on parse-stage errors. Mirrors cmd/w6c/main.c's
	// `if (l.errs || p.errs) return 1;` — broken AST otherwise reaches
	// cgen and emits junk asm with a zero exit (silent miscompile).
	if (l.errs > 0 || ps.errs > 0) { return 1; };
	if (importhead != nil) {
		importtail.next = f.list;
		f.list = importhead;
	};

	// cgen writes directly to fd 1; dup2 keeps that implementation private.
	if (out != nil) {
		let ofd: i32 = os.open(pathstr(out),
		    os.flag.WRONLY | os.flag.CREATE | os.flag.TRUNC, 420i32);	// 0o644
		if (ofd < 0) {
			let m: str = "w6c: cannot open output\n";
			os.write(2, m.ptr, m.len: u64);
			return 1;
		};
		if (os.dup2(ofd, 1i32) < 0) {
			let m: str = "w6c: dup2 failed\n";
			os.write(2, m.ptr, m.len: u64);
			os.close(ofd);
			return 1;
		};
		os.close(ofd);
	};

	let testmodule: str;
	if (testsupport != nil) { testmodule = pathstr(testsupport); };
	let interfaceout: str;
	if (wwiout != nil) { interfaceout = pathstr(wwiout); };
	return wcc.compilefile(f, testmode, testmodule, sepmode, interfaceout);
};