#include "debug.h"
#include "chunk.h"
#include "common.h"
#include "value.h"
#include <stdio.h>

void disassembleChunk(Chunk* chunk, const char* name) {
  printf("== %s ==\n", name);

  for (int offset = 0; offset < chunk->count;) {
    offset = disassembleInstruction(chunk, offset);
  }
}

static int constantInstruction(const char* name, Chunk* chunk, int offset) {
  uint8_t constant = chunk->code[offset + 1];
  printf("%-16s %4d '", name, constant);
  printValue(chunk->constants.values[constant]);
  printf("'\n");
  return offset + 2;
}

static int longConstantInstruction(const char* name, Chunk* chunk, int offset) {
  uint8_t constant_lo = chunk->code[offset + 3];
  uint8_t constant_mid = chunk->code[offset + 2];
  uint8_t constant_hi = chunk->code[offset + 1];
  int constant = constant_lo | (constant_mid << 8) | constant_hi << 16;
  printf("%-16s %9d '", name, constant);
//  printValue(chunk->constants.values[constant]);
  printf("'\n");
  return offset + 4;
}

static int simpleInstruction(const char* name, int offset) {
  printf("%s\n", name);
  return offset + 1;
}

static int byteInstruction(const char* name, Chunk* chunk, int offset) {
  uint8_t slot = chunk->code[offset + 1];
  printf("%-16s %4d\n", name, slot);
  return offset + 2;
}

static int threeByteInstruction(const char* name, Chunk* chunk, int offset) {
  uint8_t slot_lo = chunk->code[offset + 3];
  uint8_t slot_mid = chunk->code[offset + 2];
  uint8_t slot_hi = chunk->code[offset + 1];
  int slot = slot_lo | (slot_mid << 8) | slot_hi << 16;
  printf("%-16s %9d\n", name, slot);
  return offset + 2;
}

static int jumpInstruction(const char* name, int sign, Chunk* chunk, int offset) {
  uint16_t jump = (uint16_t) (chunk->code[offset + 2] << 8);
  jump |= chunk->code[offset + 1];

  printf("%-16s %4d -> %d\n", name, offset, offset + 3 + sign * jump);
  return offset + 3;
}

int disassembleInstruction(Chunk* chunk, int offset) {
  printf("%04d ", offset);
  if (offset > 0 && chunk->lines[offset] == chunk->lines[offset - 1]) {
    printf("   | ");
  } else {
    printf("%4d ", chunk->lines[offset]);
  }

  uint8_t instruction = chunk->code[offset];
  switch (instruction) {
  case OP_ARRAY:
    return byteInstruction("OP_ARRAY", chunk, offset);
  case OP_CONSTANT:
    return constantInstruction("OP_CONSTANT", chunk, offset);
  case OP_CONSTANT_LONG:
    return longConstantInstruction("OP_CONSTANT_LONG", chunk, offset);
  case OP_HASH:
    return byteInstruction("OP_HASH", chunk, offset);
  case OP_NIL:
    return simpleInstruction("OP_NIL", offset);
  case OP_TRUE:
    return simpleInstruction("OP_TRUE", offset);
  case OP_FALSE:
    return simpleInstruction("OP_FALSE", offset);
  case OP_POP:
    return simpleInstruction("OP_POP", offset);
  case OP_INDEX:
    return simpleInstruction("OP_INDEX", offset);
  case OP_GET_LOCAL:
    return byteInstruction("OP_GET_LOCAL", chunk, offset);
  case OP_SET_LOCAL:
    return byteInstruction("OP_SET_LOCAL", chunk, offset);
  case OP_GET_LOCAL_LONG:
    return threeByteInstruction("OP_GET_LOCAL_LONG", chunk, offset);
  case OP_SET_LOCAL_LONG:
    return threeByteInstruction("OP_SET_LOCAL_LONG", chunk, offset);
  case OP_GET_GLOBAL:
    return constantInstruction("OP_GET_GLOBAL", chunk, offset);
  case OP_GET_GLOBAL_LONG:
    return longConstantInstruction("OP_GET_GLOBAL_LONG", chunk, offset);
  case OP_DEFINE_GLOBAL:
    return constantInstruction("OP_DEFINE_GLOBAL", chunk, offset);
  case OP_DEFINE_GLOBAL_LONG:
    return longConstantInstruction("OP_DEFINE_GLOBAL_LONG", chunk, offset);
  case OP_SET_GLOBAL:
    return constantInstruction("OP_SET_GLOBAL", chunk, offset);
  case OP_SET_GLOBAL_LONG:
    return longConstantInstruction("OP_SET_GLOBAL_LONG", chunk, offset);
  case OP_EQUAL:
    return simpleInstruction("OP_EQUAL", offset);
  case OP_GREATER:
    return simpleInstruction("OP_GREATER", offset);
  case OP_LESS:
    return simpleInstruction("OP_LESS", offset);
  case OP_ADD:
    return simpleInstruction("OP_ADD", offset);
  case OP_SUBTRACT:
    return simpleInstruction("OP_SUBTRACT", offset);
  case OP_MULTIPLY:
    return simpleInstruction("OP_MULTIPLY", offset);
  case OP_DIVIDE:
    return simpleInstruction("OP_DIVIDE", offset);
  case OP_NOT:
    return simpleInstruction("OP_NOT", offset);
  case OP_NEGATE:
    return simpleInstruction("OP_NEGATE", offset);
  case OP_PRINT:
    return simpleInstruction("OP_PRINT", offset);
  case OP_JUMP:
    return jumpInstruction("OP_JUMP", 1, chunk, offset);
  case OP_JUMP_IF_FALSE:
    return jumpInstruction("OP_JUMP_IF_FALSE", 1, chunk, offset);
  case OP_LOOP:
    return jumpInstruction("OP_LOOP", -1, chunk, offset);
  case OP_RETURN:
    return simpleInstruction("OP_RETURN", offset);
  default:
    printf("Unknown opcode %d\n", instruction);
    return offset + 1;
  }
}