#include "vm/vm.h"
#include "vm/print.h"
#include "parse/parse.h"
#include "parse/lex.h"
#include "io.h"
#include "bitset.h"

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

void step_through(struct l2_vm *vm) {
	printf("=====\n\nInitial state:\n");
	l2_vm_print_state(vm);

	char buf[16];
	while ((enum l2_opcode)vm->ops[vm->iptr] != L2_OP_HALT) {
		size_t iptr = vm->iptr;
		printf("\n======\n\n(%d) Will run instr: ", vm->iptr);
		l2_vm_print_op(vm->ops, vm->opcount, &iptr);
		fgets(buf, sizeof(buf), stdin);
		l2_vm_step(vm);
		l2_vm_print_state(vm);
	}
}

static void usage(const char *argv0) {
	printf("Usage: %s [options] [input|-]\n", argv0);
	printf("\n");
	printf("Options:\n");
	printf("  --help:      Print this help text\n");
	printf("  --bytecode:  Print the generated bytecode, don't execute\n");
	printf("  --tokens:    Print the tokens as the program is parsed, don't execute\n");
	printf("  --step:      Step through the program\n");
}

int main(int argc, char **argv) {
	int do_print_bytecode = 0;
	int do_print_tokens = 0;
	int do_step = 0;

	int was_inf_set = 0;
	FILE *inf = stdin;

	int dashes = 0;
	for (int i = 1; i < argc; ++i) {
		if (!dashes && strcmp(argv[i], "--help") == 0) {
			usage(argv[0]);
			return 0;
		} else if (!dashes && strcmp(argv[i], "--bytecode") == 0) {
			do_print_bytecode = 1;
		} else if (!dashes && strcmp(argv[i], "--tokens") == 0) {
			do_print_tokens = 1;
		} else if (!dashes && strcmp(argv[i], "--step") == 0) {
			do_step = 1;
		} else if (strcmp(argv[i], "--") == 0) {
			dashes = 1;
		} else if (strcmp(argv[i], "-") == 0) {
			inf = stdin;
		} else if (!was_inf_set) {
			inf = fopen(argv[i], "r");
			was_inf_set = 1;
			if (inf == NULL) {
				perror(argv[i]);
				return 1;
			}
		} else {
			printf("Unexpected argument: %s\n", argv[i]);
			usage(argv[0]);
			return 1;
		}
	}

	// Init lexer with its input reader
	struct l2_io_file_reader r;
	r.r.read = l2_io_file_read;
	r.f = inf;
	struct l2_lexer lexer;
	l2_lexer_init(&lexer, &r.r);
	if (do_print_tokens) {
		lexer.do_log_tokens = 1;
	}

	// Init gen with its output writer
	struct l2_io_mem_writer w = {0};
	w.w.write = l2_io_mem_write;
	struct l2_generator gen;
	l2_gen_init(&gen, &w.w);

	struct l2_parse_error err;
	if (l2_parse_program(&lexer, &gen, &err) < 0) {
		fprintf(stderr, "Parse error: %s:%i:%i: %s\n",
				(argc == 2 ? argv[1] : "-"), err.line, err.ch, err.message);
		l2_gen_free(&gen);
		fclose(inf);
		return 1;
	}

	l2_gen_free(&gen);
	fclose(inf);

	if (do_print_bytecode) {
		l2_vm_print_bytecode((l2_word *)w.mem, w.len / sizeof(l2_word));
	}

	if (do_print_bytecode || do_print_tokens) {
		free(w.mem);
		return 0;
	}

	struct l2_vm vm;
	l2_vm_init(&vm, (void *)w.mem, w.len / sizeof(l2_word));

	if (do_step) {
		step_through(&vm);
	} else {
		l2_vm_run(&vm);
	}

	l2_vm_free(&vm);
	free(w.mem);
}