#include "types.h"

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

void interpret(Program* program) {
    Stack tape_stack;
    stack_init(&tape_stack, sizeof(void*));

    Tape* tape = malloc(sizeof(Tape));
    tape_init(tape, sizeof(void*));

    stack_push(&tape_stack, tape);
    
    Symbol s;
next:
    program_get(program, &s);
    
    switch (s) {
        case MoveLeft:
            tape_left(tape);
            break;
        case MoveRight:
            tape_right(tape);
            break;
        case Increment:
            tape_increment(tape);
            break;
        case Decrement:
            tape_decrement(tape);
            break;
        case StartLoop:
            if (tape_get(tape) == 0) {
                program_seek(program, program_get_jump(program));
            }
            break;
        case EndLoop:
            if (tape_get(tape) != 0) {
                program_seek(program, program_get_jump(program));
            }
            break;
        case PutChar: {
            printf("%c", tape_get(tape));
            break;
        }
        case GetChar: {
            tape_set(tape, getchar());
            break;
        }
        case Allocate: {
            Tape* new = malloc(sizeof(Tape));
            tape_init(new, tape_get(tape));
            memcpy(tape_ptr(tape), &new, sizeof(Tape*));
            break;
        }
        case Free: {
            Tape* old;
            memcpy(&old, tape_ptr(tape), sizeof(Tape*));
            tape_free(old);
            free(old);
            break;
        }
        case EnterTape: {
            stack_push(&tape_stack, tape);
            memcpy(&tape, tape_ptr(tape), sizeof(Tape*));
            break;
        }
        case LeaveTape: {
            tape = stack_pop(&tape_stack);
            if (tape == NULL) goto end;
            break;
        }
        case GetString: {
            fgets((char*) tape_ptr(tape), tape_get(tape), stdin);
            break;
        }
        case PutString: {
            printf("%s", (char*) tape_ptr(tape));
            break;
        }
        case Clear:
            printf("\033c");
            break;
        case Zero:
            memset(tape_ptr(tape), 0, tape_get(tape));
            break;
        case Eof:
            goto end;
    }

    program_next(program);
    goto next;
end:
    tape_free(tape);
    free(tape);

    stack_free(&tape_stack);
}