#include <getopt.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>

static const size_t buffer_size = 256;
/* static const char* asm_filename = "out.asm"; */

#define LABEL_COUNT_STACK_SIZE 256
static size_t label_stack[LABEL_COUNT_STACK_SIZE + 1] = {0};
static size_t label_stack_frame = 0;

int main(int argc, char *argv[])
{
    // int option;

    /* while ((option = getopt(argc, argv, "So:b:")) != -1) */
    /* { */
    /*     switch (option) */
    /*     { */
    /*         case 'S': */
    /*             assembly = true; */
    /*         case 'o': */
    /*             output_filename = optstring */
    /*         case 'b': */
    /*             buffer_length = atoi(optstring); */
    /*         case 'e': */
    /*             // byte, word, dword or qword */
    /*             buffer_elem = x; */
    /*     } */
    /* } */
    FILE *input_file = NULL;
    if (argc == 2)
        input_file = fopen(argv[1], "r");
    else
        input_file = stdin;

    /* FILE* output_file = fopen(asm_filename, "w"); */
    FILE *output_file = stdout;
    fprintf(
        output_file,
        "global _start\n\n"
        "section .bss\n"
        "\tbuffer: resb %zu\n\n"
        "section .text\n"
        "_start:\n"
        "\tmov rbx, buffer\n",
        buffer_size
    );
    size_t label_frame_id;

    char c;
    while ((c = fgetc(input_file)) != EOF)
    {
        switch (c)
        {
        case '>':
            fprintf(output_file, "    inc rbx                  ; >\n");
            break;
        case '<':
            fprintf(output_file, "    dec rbx                  ; <\n");
            break;
        case '+':
            fprintf(output_file, "    inc byte [rbx]           ; +\n");
            break;
        case '-':
            fprintf(output_file, "    dec byte [rbx]           ; -\n");
            break;
        case '.':
            fprintf(output_file, "    mov rdi, 1               ; .\n");
            fprintf(output_file, "    mov rsi, rbx             ; .\n");
            fprintf(output_file, "    mov rdx, 1               ; .\n");
            fprintf(output_file, "    mov rax, 1               ; .\n");
            fprintf(output_file, "    syscall                  ; .\n");
            break;
        case ',':
            fprintf(output_file, "    mov rdi, 0               ; ,\n");
            fprintf(output_file, "    mov rsi, rbx             ; ,\n");
            fprintf(output_file, "    mov rdx, 1               ; ,\n");
            fprintf(output_file, "    mov rax, 0               ; ,\n");
            fprintf(output_file, "    syscall                  ; ,\n");
            break;
        case '[':
            label_frame_id = label_stack[label_stack_frame];
            fprintf(output_file, "label_open_%03zu_%03zu:          ; [\n", label_stack_frame, label_frame_id);
            fprintf(output_file, "    cmp byte [rbx], 0        ; [\n");
            fprintf(output_file, "    je  label_close_%03zu_%03zu  ; [\n", label_stack_frame, label_frame_id);
            label_stack_frame++;
            break;
        case ']':
            label_stack_frame--;
            label_frame_id = label_stack[label_stack_frame];
            fprintf(output_file, "label_close_%03zu_%03zu:         ; ]\n", label_stack_frame, label_frame_id);
            fprintf(output_file, "    cmp byte [rbx], 0        ; ]\n");
            fprintf(output_file, "    jne label_open_%03zu_%03zu   ; ]\n", label_stack_frame, label_frame_id);
            label_stack[label_stack_frame]++;
            break;
        case ';':
            while (c != EOF && c != '\n')
                c = fgetc(input_file);
            break;
        default:
            break;
        }
    }
    fprintf(output_file, "\n");
    fprintf(output_file, "    mov rdi, 0   ; exit\n");
    fprintf(output_file, "    mov rax, 60  ; exit\n");
    fprintf(output_file, "    syscall      ; exit\n");

    return 0;
}