/* SPDX-License-Identifier: MIT */

#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <inttypes.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "asm/charmap.hpp"
#include "asm/fixpoint.hpp"
#include "asm/format.hpp"
#include "asm/fstack.hpp"
#include "asm/lexer.hpp"
#include "asm/main.hpp"
#include "asm/opt.hpp"
#include "asm/output.hpp"
#include "asm/rpn.hpp"
#include "asm/symbol.hpp"
#include "asm/warning.hpp"
#include "parser.hpp"

#include "extern/getopt.hpp"

#include "helpers.hpp"
#include "error.hpp"
#include "version.hpp"

#ifdef __clang__
#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
#define __SANITIZE_ADDRESS__
#endif // __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
#endif // __clang__

#ifdef __SANITIZE_ADDRESS__
// There are known, non-trivial to fix leaks. We would still like to have `make develop'
// detect memory corruption, though.
extern "C" {
char const *__asan_default_options(void) { return "detect_leaks=0"; }
}
#endif

// Old Bison versions (confirmed for 2.3) do not forward-declare `yyparse` in the generated header
// Unfortunately, macOS still ships 2.3, which is from 2008...
int yyparse(void);

FILE *dependfile = NULL;
bool generatedMissingIncludes = false;
bool failedOnMissingInclude = false;
bool generatePhonyDeps = false;
char *targetFileName = NULL;

bool haltNop;
bool warnOnHaltNop;
bool optimizeLoads;
bool warnOnLdOpt;
bool verbose;
bool warnings; // True to enable warnings, false to disable them.

// Escapes Make-special chars from a string
static char *make_escape(char const *str)
{
	char *escaped_str = (char *)malloc(strlen(str) * 2 + 1);
	char *dest = escaped_str;

	if (escaped_str == NULL)
		err("%s: Failed to allocate memory", __func__);

	while (*str) {
		// All dollars needs to be doubled
		if (*str == '$')
			*dest++ = '$';
		*dest++ = *str++;
	}
	*dest = '\0';

	return escaped_str;
}

// Short options
static const char *optstring = "b:D:Eg:Hhi:I:LlM:o:P:p:Q:r:VvW:w";

// Variables for the long-only options
static int depType; // Variants of `-M`

// Equivalent long options
// Please keep in the same order as short opts
//
// Also, make sure long opts don't create ambiguity:
// A long opt's name should start with the same letter as its short opt,
// except if it doesn't create any ambiguity (`verbose` versus `version`).
// This is because long opt matching, even to a single char, is prioritized
// over short opt matching
static struct option const longopts[] = {
	{ "binary-digits",    required_argument, NULL,     'b' },
	{ "define",           required_argument, NULL,     'D' },
	{ "export-all",       no_argument,       NULL,     'E' },
	{ "gfx-chars",        required_argument, NULL,     'g' },
	{ "nop-after-halt",   no_argument,       NULL,     'H' },
	{ "halt-without-nop", no_argument,       NULL,     'h' },
	{ "include",          required_argument, NULL,     'I' },
	{ "preserve-ld",      no_argument,       NULL,     'L' },
	{ "auto-ldh",         no_argument,       NULL,     'l' },
	{ "dependfile",       required_argument, NULL,     'M' },
	{ "MG",               no_argument,       &depType, 'G' },
	{ "MP",               no_argument,       &depType, 'P' },
	{ "MT",               required_argument, &depType, 'T' },
	{ "MQ",               required_argument, &depType, 'Q' },
	{ "output",           required_argument, NULL,     'o' },
	{ "preinclude",       required_argument, NULL,     'P' },
	{ "pad-value",        required_argument, NULL,     'p' },
	{ "q-precision",      required_argument, NULL,     'Q' },
	{ "recursion-depth",  required_argument, NULL,     'r' },
	{ "version",          no_argument,       NULL,     'V' },
	{ "verbose",          no_argument,       NULL,     'v' },
	{ "warning",          required_argument, NULL,     'W' },
	{ NULL,               no_argument,       NULL,     0   }
};

static void printUsage(void)
{
	fputs(
"Usage: rgbasm [-EHhLlVvw] [-b chars] [-D name[=value]] [-g chars] [-I path]\n"
"              [-M depend_file] [-MG] [-MP] [-MT target_file] [-MQ target_file]\n"
"              [-o out_file] [-P include_file] [-p pad_value] [-Q precision]\n"
"              [-r depth] [-W warning] <file>\n"
"Useful options:\n"
"    -E, --export-all         export all labels\n"
"    -M, --dependfile <path>  set the output dependency file\n"
"    -o, --output <path>      set the output object file\n"
"    -p, --pad-value <value>  set the value to use for `ds'\n"
"    -V, --version            print RGBASM version and exit\n"
"    -W, --warning <warning>  enable or disable warnings\n"
"\n"
"For help, use `man rgbasm' or go to https://rgbds.gbdev.io/docs/\n",
	      stderr);
}

int main(int argc, char *argv[])
{
	time_t now = time(NULL);
	char const *sourceDateEpoch = getenv("SOURCE_DATE_EPOCH");

	// Support SOURCE_DATE_EPOCH for reproducible builds
	// https://reproducible-builds.org/docs/source-date-epoch/
	if (sourceDateEpoch)
		now = (time_t)strtoul(sourceDateEpoch, NULL, 0);

	// Perform some init for below
	sym_Init(now);

	// Set defaults

	opt_B("01");
	opt_G("0123");
	opt_P(0);
	opt_Q(16);
	haltNop = false;
	warnOnHaltNop = true;
	optimizeLoads = false;
	warnOnLdOpt = true;
	verbose = false;
	warnings = true;
	sym_SetExportAll(false);
	uint32_t maxDepth = DEFAULT_MAX_DEPTH;
	char const *dependFileName = NULL;
	size_t targetFileNameLen = 0;

	for (int ch; (ch = musl_getopt_long_only(argc, argv, optstring, longopts, NULL)) != -1;) {
		switch (ch) {
			char *endptr;

		case 'b':
			if (strlen(musl_optarg) == 2)
				opt_B(musl_optarg);
			else
				errx("Must specify exactly 2 characters for option 'b'");
			break;

			char *equals;
		case 'D':
			equals = strchr(musl_optarg, '=');
			if (equals) {
				*equals = '\0';
				sym_AddString(musl_optarg, equals + 1);
			} else {
				sym_AddString(musl_optarg, "1");
			}
			break;

		case 'E':
			sym_SetExportAll(true);
			break;

		case 'g':
			if (strlen(musl_optarg) == 4)
				opt_G(musl_optarg);
			else
				errx("Must specify exactly 4 characters for option 'g'");
			break;

		case 'H':
			if (warnOnHaltNop)
				warning(WARNING_OBSOLETE,
					"Automatic `nop` after `halt` is deprecated\n");
			else
				errx("`-H` and `-h` don't make sense together");
			haltNop = true;
			warnOnHaltNop = false;
			break;
		case 'h':
			if (haltNop)
				errx("`-H` and `-h` don't make sense together");
			break;

		// `-i` was the only short option for `--include` until `-I` was
		// introduced to better match the `-I dir` option of gcc and clang.
		case 'i':
			warning(WARNING_OBSOLETE, "`-i` is deprecated; use `-I`\n");
			// fallthrough
		case 'I':
			fstk_AddIncludePath(musl_optarg);
			break;

		case 'L':
			if (optimizeLoads)
				errx("`-L` and `-l` don't make sense together");
			break;
		case 'l':
			if (warnOnLdOpt)
				warning(WARNING_OBSOLETE,
					"Automatic `ld` to `ldh` optimization is deprecated\n");
			else
				errx("`-L` and `-l` don't make sense together");
			optimizeLoads = true;
			warnOnLdOpt = false;
			break;

		case 'M':
			if (dependfile)
				warnx("Overriding dependfile %s", dependFileName);
			if (!strcmp("-", musl_optarg)) {
				dependfile = stdout;
				dependFileName = "<stdout>";
			} else {
				dependfile = fopen(musl_optarg, "w");
				dependFileName = musl_optarg;
			}
			if (dependfile == NULL)
				err("Could not open dependfile %s", dependFileName);
			break;

		case 'o':
			out_SetFileName(musl_optarg);
			break;

		case 'P':
			fstk_SetPreIncludeFile(musl_optarg);
			break;

			unsigned long padByte;
		case 'p':
			padByte = strtoul(musl_optarg, &endptr, 0);

			if (musl_optarg[0] == '\0' || *endptr != '\0')
				errx("Invalid argument for option 'p'");

			if (padByte > 0xFF)
				errx("Argument for option 'p' must be between 0 and 0xFF");

			opt_P(padByte);
			break;

			unsigned long precision;
			const char *precisionArg;
		case 'Q':
			precisionArg = musl_optarg;
			if (precisionArg[0] == '.')
				precisionArg++;
			precision = strtoul(precisionArg, &endptr, 0);

			if (musl_optarg[0] == '\0' || *endptr != '\0')
				errx("Invalid argument for option 'Q'");

			if (precision < 1 || precision > 31)
				errx("Argument for option 'Q' must be between 1 and 31");

			opt_Q(precision);
			break;

		case 'r':
			maxDepth = strtoul(musl_optarg, &endptr, 0);

			if (musl_optarg[0] == '\0' || *endptr != '\0')
				errx("Invalid argument for option 'r'");
			break;

		case 'V':
			printf("rgbasm %s\n", get_package_version_string());
			exit(0);

		case 'v':
			verbose = true;
			break;

		case 'W':
			processWarningFlag(musl_optarg);
			break;

		case 'w':
			warnings = false;
			break;

		// Long-only options
		case 0:
			switch (depType) {
			case 'G':
				generatedMissingIncludes = true;
				break;

			case 'P':
				generatePhonyDeps = true;
				break;

				char *newTarget;
			case 'Q':
			case 'T':
				newTarget = musl_optarg;
				if (depType == 'Q')
					newTarget = make_escape(newTarget);
				size_t newTargetLen = strlen(newTarget) + 1; // Plus the space

				targetFileName = (char *)realloc(targetFileName,
							 targetFileNameLen + newTargetLen + 1);
				if (targetFileName == NULL)
					err("Cannot append new file to target file list");
				memcpy(&targetFileName[targetFileNameLen], newTarget, newTargetLen);
				if (depType == 'Q')
					free(newTarget);
				targetFileNameLen += newTargetLen;
				targetFileName[targetFileNameLen - 1] = ' ';
				break;
			}
			break;

		// Unrecognized options
		default:
			fprintf(stderr, "FATAL: unknown option '%c'\n", ch);
			printUsage();
			exit(1);
		}
	}

	if (targetFileName == NULL)
		targetFileName = objectName;
	else
		targetFileName[targetFileNameLen - 1] = '\0'; // Overwrite the last space

	if (argc == musl_optind) {
		fputs("FATAL: Please specify an input file (pass `-` to read from standard input)\n", stderr);
		printUsage();
		exit(1);
	} else if (argc != musl_optind + 1) {
		fputs("FATAL: More than one input file specified\n", stderr);
		printUsage();
		exit(1);
	}

	char const *mainFileName = argv[musl_optind];

	if (verbose)
		printf("Assembling %s\n", mainFileName);

	if (dependfile) {
		if (!targetFileName)
			errx("Dependency files can only be created if a target file is specified with either -o, -MQ or -MT");

		fprintf(dependfile, "%s: %s\n", targetFileName, mainFileName);
	}

	charmap_New(DEFAULT_CHARMAP_NAME, NULL);

	// Init lexer and file stack, providing file info
	lexer_Init();
	fstk_Init(mainFileName, maxDepth);

	// Perform parse (yyparse is auto-generated from `parser.y`)
	if (yyparse() != 0 && nbErrors == 0)
		nbErrors = 1;

	if (dependfile)
		fclose(dependfile);

	sect_CheckUnionClosed();

	if (nbErrors != 0)
		errx("Assembly aborted (%u error%s)!", nbErrors,
			nbErrors == 1 ? "" : "s");

	// If parse aborted due to missing an include, and `-MG` was given, exit normally
	if (failedOnMissingInclude)
		return 0;

	// If no path specified, don't write file
	if (objectName != NULL)
		out_WriteObject();
	return 0;
}
