/*
** proc.c - Proc class
**
** See Copyright Notice in mruby.h
*/

#include "mruby.h"
#include "mruby/class.h"
#include "mruby/proc.h"
#include "mruby/opcode.h"

static mrb_code call_iseq[] = {
  MKOP_A(OP_CALL, 0),
};

struct RProc *
mrb_proc_new(mrb_state *mrb, mrb_irep *irep)
{
  struct RProc *p;
  mrb_callinfo *ci = mrb->c->ci;

  p = (struct RProc*)mrb_obj_alloc(mrb, MRB_TT_PROC, mrb->proc_class);
  p->target_class = 0;
  if (ci) {
    if (ci->proc)
      p->target_class = ci->proc->target_class;
    if (!p->target_class)
      p->target_class = ci->target_class;
  }
  p->body.irep = irep;
  p->env = 0;
  mrb_irep_incref(mrb, irep);

  return p;
}

static inline void
closure_setup(mrb_state *mrb, struct RProc *p, int nlocals)
{
  struct REnv *e;

  if (!mrb->c->ci->env) {
    e = (struct REnv*)mrb_obj_alloc(mrb, MRB_TT_ENV, (struct RClass*)mrb->c->ci->proc->env);
    MRB_ENV_STACK_LEN(e)= (unsigned int)nlocals;
    e->mid = mrb->c->ci->mid;
    e->cioff = mrb->c->ci - mrb->c->cibase;
    e->stack = mrb->c->stack;
    mrb->c->ci->env = e;
  }
  else {
    e = mrb->c->ci->env;
  }
  p->env = e;
}

struct RProc *
mrb_closure_new(mrb_state *mrb, mrb_irep *irep)
{
  struct RProc *p = mrb_proc_new(mrb, irep);

  closure_setup(mrb, p, mrb->c->ci->proc->body.irep->nlocals);
  return p;
}

struct RProc *
mrb_proc_new_cfunc(mrb_state *mrb, mrb_func_t func)
{
  struct RProc *p;

  p = (struct RProc*)mrb_obj_alloc(mrb, MRB_TT_PROC, mrb->proc_class);
  p->body.func = func;
  p->flags |= MRB_PROC_CFUNC;
  p->env = 0;

  return p;
}

MRB_API struct RProc *
mrb_closure_new_cfunc(mrb_state *mrb, mrb_func_t func, int nlocals)
{
  struct RProc *p = mrb_proc_new_cfunc(mrb, func);

  closure_setup(mrb, p, nlocals);
  return p;
}

void
mrb_proc_copy(struct RProc *a, struct RProc *b)
{
  a->flags = b->flags;
  a->body = b->body;
  if (!MRB_PROC_CFUNC_P(a)) {
    a->body.irep->refcnt++;
  }
  a->target_class = b->target_class;
  a->env = b->env;
}

static mrb_value
mrb_proc_initialize(mrb_state *mrb, mrb_value self)
{
  mrb_value blk;

  mrb_get_args(mrb, "&", &blk);
  if (mrb_nil_p(blk)) {
    /* Calling Proc.new without a block is not implemented yet */
    mrb_raise(mrb, E_ARGUMENT_ERROR, "tried to create Proc object without a block");
  }
  else {
    mrb_proc_copy(mrb_proc_ptr(self), mrb_proc_ptr(blk));
  }
  return self;
}

static mrb_value
mrb_proc_init_copy(mrb_state *mrb, mrb_value self)
{
  mrb_value proc;

  mrb_get_args(mrb, "o", &proc);
  if (mrb_type(proc) != MRB_TT_PROC) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "not a proc");
  }
  mrb_proc_copy(mrb_proc_ptr(self), mrb_proc_ptr(proc));
  return self;
}

int
mrb_proc_cfunc_p(struct RProc *p)
{
  return MRB_PROC_CFUNC_P(p);
}

mrb_value
mrb_proc_call_cfunc(mrb_state *mrb, struct RProc *p, mrb_value self)
{
  return (p->body.func)(mrb, self);
}

mrb_code*
mrb_proc_iseq(mrb_state *mrb, struct RProc *p)
{
  return p->body.irep->iseq;
}

/* 15.2.17.4.2 */
static mrb_value
mrb_proc_arity(mrb_state *mrb, mrb_value self)
{
  struct RProc *p = mrb_proc_ptr(self);
  mrb_code *iseq = mrb_proc_iseq(mrb, p);
  mrb_aspec aspec;
  int ma, ra, pa, arity;

  if (MRB_PROC_CFUNC_P(p)) {
    /* TODO cfunc aspec not implemented yet */
    return mrb_fixnum_value(-1);
  }

  /* arity is depend on OP_ENTER */
  if (GET_OPCODE(*iseq) != OP_ENTER) {
    return mrb_fixnum_value(0);
  }

  aspec = GETARG_Ax(*iseq);
  ma = MRB_ASPEC_REQ(aspec);
  ra = MRB_ASPEC_REST(aspec);
  pa = MRB_ASPEC_POST(aspec);
  arity = ra ? -(ma + pa + 1) : ma + pa;

  return mrb_fixnum_value(arity);
}

/* 15.3.1.2.6  */
/* 15.3.1.3.27 */
/*
 * call-seq:
 *   lambda { |...| block }  -> a_proc
 *
 * Equivalent to <code>Proc.new</code>, except the resulting Proc objects
 * check the number of parameters passed when called.
 */
static mrb_value
proc_lambda(mrb_state *mrb, mrb_value self)
{
  mrb_value blk;
  struct RProc *p;

  mrb_get_args(mrb, "&", &blk);
  if (mrb_nil_p(blk)) {
    mrb_raise(mrb, E_ARGUMENT_ERROR, "tried to create Proc object without a block");
  }
  p = mrb_proc_ptr(blk);
  if (!MRB_PROC_STRICT_P(p)) {
    struct RProc *p2 = (struct RProc*)mrb_obj_alloc(mrb, MRB_TT_PROC, p->c);
    mrb_proc_copy(p2, p);
    p2->flags |= MRB_PROC_STRICT;
    return mrb_obj_value(p2);
  }
  return blk;
}

void
mrb_init_proc(mrb_state *mrb)
{
  struct RProc *m;
  mrb_irep *call_irep = (mrb_irep *)mrb_malloc(mrb, sizeof(mrb_irep));
  static const mrb_irep mrb_irep_zero = { 0 };

  *call_irep = mrb_irep_zero;
  call_irep->flags = MRB_ISEQ_NO_FREE;
  call_irep->iseq = call_iseq;
  call_irep->ilen = 1;

  mrb_define_method(mrb, mrb->proc_class, "initialize", mrb_proc_initialize, MRB_ARGS_NONE());
  mrb_define_method(mrb, mrb->proc_class, "initialize_copy", mrb_proc_init_copy, MRB_ARGS_REQ(1));
  mrb_define_method(mrb, mrb->proc_class, "arity", mrb_proc_arity, MRB_ARGS_NONE());

  m = mrb_proc_new(mrb, call_irep);
  mrb_define_method_raw(mrb, mrb->proc_class, mrb_intern_lit(mrb, "call"), m);
  mrb_define_method_raw(mrb, mrb->proc_class, mrb_intern_lit(mrb, "[]"), m);

  mrb_define_class_method(mrb, mrb->kernel_module, "lambda", proc_lambda, MRB_ARGS_NONE()); /* 15.3.1.2.6  */
  mrb_define_method(mrb, mrb->kernel_module,       "lambda", proc_lambda, MRB_ARGS_NONE()); /* 15.3.1.3.27 */
}
