#include <stdlib.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>

#include "types.h"
#include "token.h"
#include "lex.h"

#define assert(c)  while (!(c)) __builtin_unreachable()

static void
usage(void)
{
	printf("lc [--lex|---parse|--validate|--codegen] [-c] <source>\n");
}

/* The different stages */
enum stage {
	Snone,
	Slex,
	Sparse,
	Svalidate,
	Scodegen,
	Semit,
};

static char *stagename[Semit+1] = {
	[Slex] = "lex",
	[Sparse] = "parse",
	[Svalidate] = "validate",
	[Scodegen] = "codegen",
	[Semit] = "emit",
};

/* options */
static char *infname = 0;
static enum stage stage = Snone;
static bool obj = false;

static bool
parseargs(usize argc, char *argv[])
{
	char *arg;
	usize len;

	for (usize i = 0; i < argc; i++) {
		arg = argv[i];
		len = strlen(arg);
		if (arg[0] == '-') {
			if (len < 2) {
				fprintf(stderr, "error: not an option: -\n");
				return false;
			}
			if (len == 2 && arg[1] == 'c') {
				obj = true;
				continue;
			}
			if (arg[1] != '-') {
				fprintf(stderr, "error: unrecognised option: %s\n", arg);
				return false;
			}
			/* we've seen --, check for options */
			enum stage newstage = Snone;
			if (!strncmp(&arg[2], "lex", len-2)) {
				newstage = Slex;
			} else if (!strncmp(&arg[2], "parse", len-2)) {
				newstage = Sparse;
			} else if (!strncmp(&arg[2], "validate", len-2)) {
				newstage = Svalidate;
			} else if (!strncmp(&arg[2], "codegen", len-2)) {
				newstage = Svalidate;
			} else if (!strncmp(&arg[2], "emit", len-2)) {
				newstage = Svalidate;
			}
			if (newstage) {
				if (stage) {
					fprintf(stderr,
						"error: conflicting options: --%s and --%s cannot be specified at the same time\n",
						stagename[stage], stagename[newstage]);
					return false;
				}
				stage = newstage;
				continue;
			}
			fprintf(stderr, "error: unrecognised option: %s\n", arg);
			return false;
		}
		if (infname) {
			fprintf(stderr, "warning: multiple input files are not yet implemented. Ignoring %s\n", arg);
			continue;
		}
		infname = arg;
	}
	if (!infname) {
		fprintf(stderr, "error: no input file provided\n");
		return false;
	}

	if (stage == Snone)
		stage = Semit;
	return true;
}

int
main(int argc, char *argv[])
{
	/* parse arguments */
	if (argc < 2) {
		usage();
		exit(EXIT_SUCCESS);
	}
	argc--;
	argv++;
	if (!parseargs((usize)argc, argv)) {
		usage();
		exit(EXIT_FAILURE);
	}

	printf("stage = %s\n", stagename[stage]);
	printf("input = %s\n", infname);

	struct lexstate lexer;
	lexreset(&lexer);
	u8 code[] = "   \n\n  int\nmain(void)\n{\n\treturn 2;\n}\n";
	lexfeed(&lexer, sizeof(code)-1, code);

	lex(&lexer);

	/* call preprocessor */

	/* call main compiler */

	/* call assembler */
}