#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "compiler/pre.h"
#include "compiler/lex.h"
#include "compiler/parse.h"
#include "compiler/sema.h"
#include "compiler/state.h"
#include "compiler/codegen.h"
#include "compiler/messages.h"

#include "compiler/libs/optparse.h"
#include "compiler/libs/stb_ds.h"

#ifndef GIT_HASH
#	define GIT_HASH "<no hash>"
#endif
#ifndef BUG_REPORT_URL
#	define BUG_REPORT_URL "https://codeberg.org/tocariimaa/rutile"
#endif
#ifndef TARGET_EXE_EXT /* without prefix dot! */
#	define TARGET_EXE_EXT Sl("")
#endif

static const char *HelpMessage = 													\
	"Summary of common options:\n"													\
	"  -c\tCompile only. Don't link, output an object file instead.\n" 				\
	"  -d\tDefine a constant with the specified value.\n" 							\
	"  -h\tPrint this help message.\n" 												\
	"  -o\tSet output file name of the executable/object file.\n" 					\
	"  -v\tPrint the version of this compiler, plus other relevant information.\n" 	\
	"  -S\tEmit intermediate code.\n" 												\
	"  -R\tSet the code generation mode, 'release' for an optimized build,\n" 		\
	"  \t'debug' for a debug build.\n" 												\
	;

/* Creates the output binary file name, changing the extension to the current platform
 * executable file extension, or it simply removes the original extension if the platform
 * has no binary extension, (i.e UNIX-likes OSes). */
static Str
make_binary_filename(Compiler *cm, Str src_filename, const Str exe_ext)
{
	bool exe_has_ext = exe_ext.len > 0;
	const size_t ss = src_filename.len;
	Assert(ss != 0);
	char *buf = malloc(ss + 2 + (exe_has_ext ? exe_ext.len : 0));
	memcpy(buf, src_filename.s, ss);
	buf[ss] = '\0';

	char *p = buf + (ss - 1);
	while (p != buf && *p != '.') /* Search for the first '.' backwards */
		--p;
	/* No extension in filename, egde case really */
	if (p == buf) {
		if (!exe_has_ext)
			fatal(cm, nil, "output file name required in this case (host OS binary format lacks extension)");
		/* append extension then */
		p = buf + ss;
		*p = '.';
	}
	if (exe_has_ext) {
		memcpy(++p, exe_ext.s, exe_ext.len);
		p += 3;
	}
	*p = '\0';
	return Str_from_c(buf);
}

static enum CodegenBackends
backend_from_str(Compiler *cm, Str s)
{
	if (s.len == 1 && (s.s[0] == 'c' || s.s[0] == 'C'))
		return CgBackendC;
	else if (Str_equal(s, Sl("gcc")))
		return CgBackendLibGccJit;
	fatal(cm, nil, "unknown backend '%s'", s.s);
	unreachable();
}

static Str
cli_boilerplate(char **argv, Compiler *cm)
{
	const struct optparse_long longopts[] = {
		{"backend", 'b', OPTPARSE_REQUIRED},
		{"compile-only", 'c', OPTPARSE_NONE},
		{"define", 'd', OPTPARSE_REQUIRED},
		{"max-errors", 'E', OPTPARSE_REQUIRED},
		{"release", 'R', OPTPARSE_REQUIRED},
		{"emit-ir", 'S', OPTPARSE_OPTIONAL},
		{"exe", 'o', OPTPARSE_REQUIRED},
		{"version", 'v', OPTPARSE_NONE},
		{"help", 'h', OPTPARSE_NONE},
		{0},
	};

	const char *no_fun_env = getenv("NO_COLOR");
	cm->opts.color = isatty(STDERR_FILENO) && !(no_fun_env != nil && *no_fun_env != '\0');

	struct optparse opts;
	optparse_init(&opts, argv);

	i8 opt;
	while ((opt = optparse_long(&opts, longopts, nil)) != -1) {
		switch (opt) {
		case 'b':
			cm->opts.backend = backend_from_str(cm, Str_from_c(opts.optarg));
			break;
		case 'c':
			cm->opts.compile_only = true;
			break;
		case 'd':
			trace("define: %s\n", opts.optarg);
			arrput(cm->opts.defines, Str_from_c(opts.optarg));
			break;
		case 'h':
			printf("Usage: %s [options...] files...\n\n%s\n", *argv, HelpMessage);
			exit(0);
		case 'E':
			cm->opts.max_errors = atoi(opts.optarg); /* XXX: atoi LOL */
			break;
		case 'R':
			trace("release: %s\n", opts.optarg);
			cm->opts.release_mode = Str_from_c(opts.optarg);
			break;
		case 'S':
			break;
		case 'o':
		   	cm->opts.exe_out = Str_from_c(opts.optarg);
			break;
		case 'v':
			printf("Rutile compiler v0.0.1\n");
			printf("git commit: %s\nReport bugs here: %s\n", GIT_HASH, BUG_REPORT_URL);
			exit(0);
		case '?':
			fatal(cm, nil, "%s: %s", *argv, opts.errmsg);
		}
	}

	const char *src_filename = optparse_arg(&opts);
	if (src_filename == nil)
		fatal(cm, nil, "no input files specified");
	return Str_from_c(src_filename);
}

int
main(int argc, char **argv)
{
	(void)argc;
	Compiler cm = {
		.opts = {
			.backend = CgBackendC,
			.max_errors = 20,
		}
	};

	Str src_filename = cli_boilerplate(argv, &cm);
	FILE *src_in = nil;

	if (src_filename.s[0] == '-' && src_filename.s[1] == '\0') {
		src_in = stdin;
		src_filename = Sl("<stdin>");
	} else {
		if ((src_in = fopen((char *)src_filename.s, "rb")) == nil) {
			fatal(&cm, nil, "can't open: %s", src_filename.s);
		}
	}

	cm.current_filename = src_filename;
	if (cm.opts.exe_out.len == 0)
		cm.opts.exe_out = make_binary_filename(&cm, src_filename, TARGET_EXE_EXT);

	if (Str_equal(cm.opts.exe_out, cm.current_filename)) {
		fatal(&cm, nil, "input source file and output file are the same");
	}
	
	/* Compiler pipeline */
	LexState *ls = lex_new(&cm, src_in, src_filename, 4);
	ParserState *ps = parse_new(&cm, ls);
	SemaCtx *ss = sema_new(&cm);
	Ast *program = parse(ps);
	if (!ps->ok)
		goto err;
	sema(ss, program);
	if (!ss->ok)
		goto err;

	CodegenCtx *cgctx = codegen_new(&cm, cm.opts.backend);
	codegen(cgctx, program);
	codegen_destroy(cgctx);
err:
	sema_destroy(ss);
	parse_destroy(ps);
	lex_destroy(ls);
	fclose(src_in);

	return 0;
}