#include "display.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>

struct position {
  int x;
  int y;
};

typedef struct position position;

struct state {
  position current;
  position prev;
  bool pen;
  display *d;
};

typedef struct state state;

enum { DX, DY, DT, PEN};

int getOpcode(unsigned char bin) {
  return (bin >> 6);
}

int getOperand(unsigned char bin, int opcode) {
  if (opcode == 0 || opcode == 1) {
    return ((bin & 0x3F) - (((bin >> 5) & 1)*64));
  }
  else return (bin & 0x3F);
}

char *initializeFile(char *args) {
  char *file[11] = {"line", "square", "box", "oxo", "diag", "cross", "clear", "key", "pauses", "field", "lawn"};
  char *filename[12] = {"line.sketch", "square.sketch", "box.sketch", "oxo.sketch", "diag.sketch", "cross.sketch", "clear.sketch", "key.sketch", "pauses.sketch", "field.sketch", "lawn.sketch"};
 for (int i = 0; i < 12; i++) {
    if (strcmp(args, file[i]) == 0) {
      return *(filename + i);
    }
  }
  return "error";
}


void Operation(state *s, int value, int opcode) {
  if(opcode == DX){
    s->current.x += value;
  }
  else if(opcode == DY){
    s->current.y += value;
    if(s->pen == true){
      line(s->d, s->prev.x, s->prev.y, s->current.x, s->current.y);
    }
    s->prev = s-> current;
    }
  else if(opcode == DT) {
    pause(s->d, value *10);
  }
  else if(opcode == PEN) {
    s -> pen = !s -> pen;
  }
}



void runFile(char *args) {
    char *arg = initializeFile(args);
    FILE *in = fopen(arg, "rb");
    display *d = newDisplay(arg, 200, 200);
    if (strcmp(args,"error")==0){
        exit(1);
    }
    position start = {0, 0};
    state s = {start, start, false, d};
    unsigned char bin = fgetc(in);
    while (! feof(in)) {
      int opcode = getOpcode(bin);
      int operand = getOperand(bin, opcode);
      Operation(&s, operand, opcode);
      bin = fgetc(in);
    }
    end(d);
    fclose(in);
  }

  int main(int n, char **args) {
   if (n == 1) {
      printf("x");
    } else if (n == 2) {
      runFile(args[1]);
    return 0;
  }
  }