#include <common/fzl_types.h>
#include <compiler/fzl_gen.h>
#include <compiler/internals/gen.h>
#include <stdbool.h>
#include <stdio.h>

// While or for loops
gen_res_t gen_loop(fzl_gen_t *gen, fzl_node_t *node)
{
  if (!gen || !node)
    return gen_error;

  fzl_gen_ctx_t *ctx = gen_ctx(gen, FZL_GEN_CTX_TYPE_LOOP, node);
  if (!ctx)
    return gen_error;

  gen_op(gen, FZL_OPCODE_MK_ENVTABLE);

  if (node->loop.init)
    if (gen_common(gen, node->loop.init).error)
      return gen_error;

  size_t start_ip = gen->ops_count;
  if (node->loop.cond)
  {
    if (gen_common(gen, node->loop.cond).error)
      return gen_error;
  }
  else
  {
    gen_op(gen, FZL_OPCODE_PUSHNUM);
    gen_word(gen, 1);
  }

  gen_op(gen, FZL_OPCODE_JZ);
  ctx->loop.breaks[ctx->loop.breaks_count++] = gen->ops_count;
  gen_word(gen, 0);

  if (gen_common(gen, node->loop.body).error)
    return gen_error;

  if (node->loop.step)
    if (gen_common(gen, node->loop.step).error)
      return gen_error;

  gen_op(gen, FZL_OPCODE_JMP);
  gen_word(gen, start_ip);

  // backpatch `break`s
  for (size_t i = 0; i < ctx->loop.breaks_count; i++)
    gen->ops[ctx->loop.breaks[i]] = gen->ops_count;

  gen_op(gen, FZL_OPCODE_RM_ENVTABLE);

  for (size_t i = gen->syms_top - 1; i > ctx->level; i--)
    fzl_freesymt(gen->syms[--gen->syms_top]);

  ctx = gen_fin_ctx(gen);
  if (!ctx)
    return gen_error;

  return gen_ok_null;
}