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

#ifndef MRUBY_PROC_H
#define MRUBY_PROC_H

#include "common.h"
#include <mruby/irep.h>
#include <string.h>

/**
 * Proc class
 */
MRB_BEGIN_DECL

/*
 * env object (for internal used)
 *
 * - don't create multiple envs on one ci.
 * - don't share a env to different ci.
 * - don't attach a closed env to any ci.
 */
struct REnv {
  MRB_OBJECT_HEADER;
  mrb_value *stack;
  struct mrb_context *cxt; /* if not null, it means that the stack is shared with the call frame */
  mrb_sym mid;
};

/* flags (20bits): 1(ZERO):1(separate module):2(visibility):8(cioff/bidx):8(stack_len) */
#define MRB_ENV_SET_LEN(e,len) ((e)->flags = (((e)->flags & ~0xff)|((unsigned int)(len) & 0xff)))
#define MRB_ENV_LEN(e) ((mrb_int)((e)->flags & 0xff))
#define MRB_ENV_CLOSE(e) ((e)->cxt = NULL)
#define MRB_ENV_ONSTACK_P(e) ((e)->cxt != NULL)
#define MRB_ENV_BIDX(e) (((e)->flags >> 8) & 0xff)
#define MRB_ENV_SET_BIDX(e,idx) ((e)->flags = (((e)->flags & ~(0xff<<8))|((unsigned int)(idx) & 0xff)<<8))
#define MRB_ENV_SET_VISIBILITY(e, vis) MRB_FLAGS_SET((e)->flags, 16, 2, vis)
#define MRB_ENV_VISIBILITY(e) MRB_FLAGS_GET((e)->flags, 16, 2)
#define MRB_ENV_VISIBILITY_BREAK_P(e) MRB_FLAG_CHECK((e)->flags, 18)
#define MRB_ENV_COPY_FLAGS_FROM_CI(e, ci) MRB_FLAGS_SET((e)->flags, 16, 3, (ci)->vis)

/*
 * Returns TRUE on success.
 * If the function fails:
 * * Returns FALSE if noraise is TRUE.
 * * Raises a NoMemoryError exception if noraise is FALSE.
 */
mrb_bool mrb_env_unshare(mrb_state*, struct REnv*, mrb_bool noraise);

struct RProc {
  MRB_OBJECT_HEADER;
  union {
    const mrb_irep *irep;
    mrb_func_t func;
    mrb_sym mid;
  } body;
  const struct RProc *upper;
  union {
    struct RClass *target_class;
    struct REnv *env;
  } e;
};

/* aspec access */
#define MRB_ASPEC_REQ(a)          (((a) >> 18) & 0x1f)
#define MRB_ASPEC_OPT(a)          (((a) >> 13) & 0x1f)
#define MRB_ASPEC_REST(a)         (((a) >> 12) & 0x1)
#define MRB_ASPEC_POST(a)         (((a) >> 7) & 0x1f)
#define MRB_ASPEC_KEY(a)          (((a) >> 2) & 0x1f)
#define MRB_ASPEC_KDICT(a)        (((a) >> 1) & 0x1)
#define MRB_ASPEC_BLOCK(a)        ((a) & 1)
#define MRB_ASPEC_NOBLOCK(a)      (((a) >> 23) & 0x1)

#define MRB_PROC_CFUNC_FL 128
#define MRB_PROC_CFUNC_P(p) (((p)->flags & MRB_PROC_CFUNC_FL) != 0)
#define MRB_PROC_CFUNC(p) (p)->body.func
#define MRB_PROC_STRICT 256
#define MRB_PROC_STRICT_P(p) (((p)->flags & MRB_PROC_STRICT) != 0)
#define MRB_PROC_ORPHAN 512
#define MRB_PROC_ORPHAN_P(p) (((p)->flags & MRB_PROC_ORPHAN) != 0)
#define MRB_PROC_ENVSET 1024
#define MRB_PROC_ENV_P(p) (((p)->flags & MRB_PROC_ENVSET) != 0)
#define MRB_PROC_ENV(p) (MRB_PROC_ENV_P(p) ? (p)->e.env : NULL)
#define MRB_PROC_TARGET_CLASS(p) (MRB_PROC_ENV_P(p) ? (p)->e.env->c : (p)->e.target_class)
#define MRB_PROC_SET_TARGET_CLASS(p,tc) do {\
  if (MRB_PROC_ENV_P(p)) {\
    (p)->e.env->c = (tc);\
    mrb_field_write_barrier(mrb, (struct RBasic*)(p)->e.env, (struct RBasic*)(tc));\
  }\
  else {\
    (p)->e.target_class = (tc);\
    mrb_field_write_barrier(mrb, (struct RBasic*)p, (struct RBasic*)(tc));\
  }\
} while (0)
#define MRB_PROC_SCOPE 2048
#define MRB_PROC_SCOPE_P(p) (((p)->flags & MRB_PROC_SCOPE) != 0)
#define MRB_PROC_NOARG 4096 /* for MRB_PROC_CFUNC_FL, aspec == MRB_ARGS_NONE() */
#define MRB_PROC_NOARG_P(p) (((p)->flags & MRB_PROC_NOARG) != 0)
#define MRB_PROC_ALIAS 8192
#define MRB_PROC_ALIAS_P(p) (((p)->flags & MRB_PROC_ALIAS) != 0)

/* Compressed aspec for cfunc procs (13 bits in RProc.flags).
 * Uses free bits 0-6 and 14-19 to store a compressed argument spec.
 * Layout: block(0) kdict(1) key(2-3) post(4-5) rest(6) opt(14-16) req(17-19)
 * Field widths are smaller than the full 24-bit aspec: req/opt max 7, post/key max 3.
 * Values exceeding the compressed range are clamped and rest is forced to 1. */
#define MRB_PROC_CASPEC_MASK  0xfc07fu  /* bits 0-6 and 14-19 */

static inline uint32_t
mrb_proc_compress_aspec(mrb_aspec aspec)
{
  uint32_t req   = MRB_ASPEC_REQ(aspec);
  uint32_t opt   = MRB_ASPEC_OPT(aspec);
  uint32_t rest  = MRB_ASPEC_REST(aspec);
  uint32_t post  = MRB_ASPEC_POST(aspec);
  uint32_t key   = MRB_ASPEC_KEY(aspec);
  uint32_t kdict = MRB_ASPEC_KDICT(aspec);
  uint32_t block = MRB_ASPEC_BLOCK(aspec);

  if (req > 7 || opt > 7 || post > 3 || key > 3) {
    if (req > 7) req = 7;
    if (opt > 7) opt = 7;
    if (post > 3) post = 3;
    if (key > 3) key = 3;
    rest = 1;
  }

  return block | (kdict << 1) | (key << 2) | (post << 4) | (rest << 6)
       | (opt << 14) | (req << 17);
}

static inline mrb_aspec
mrb_proc_decompress_caspec(uint32_t flags)
{
  return (((flags >> 17) & 0x7) << 18)  /* req */
       | (((flags >> 14) & 0x7) << 13)  /* opt */
       | (((flags >> 6) & 0x1) << 12)   /* rest */
       | (((flags >> 4) & 0x3) << 7)    /* post */
       | (((flags >> 2) & 0x3) << 2)    /* key */
       | (((flags >> 1) & 0x1) << 1)    /* kdict */
       | (flags & 0x1);                 /* block */
}

static inline void
mrb_proc_set_cfunc_aspec(struct RProc *p, mrb_aspec aspec)
{
  p->flags &= ~(MRB_PROC_NOARG | MRB_PROC_CASPEC_MASK);
  if (aspec == 0) {
    p->flags |= MRB_PROC_NOARG;
  }
  else {
    p->flags |= mrb_proc_compress_aspec(aspec);
  }
}

#define mrb_proc_ptr(v)    ((struct RProc*)(mrb_ptr(v)))

struct RProc *mrb_proc_new(mrb_state*, const mrb_irep*);
MRB_API struct RProc *mrb_proc_new_cfunc(mrb_state*, mrb_func_t);
MRB_API struct RProc *mrb_closure_new_cfunc(mrb_state *mrb, mrb_func_t func, int nlocals);

/* following functions are defined in mruby-proc-ext so please include it when using */
MRB_API struct RProc *mrb_proc_new_cfunc_with_env(mrb_state *mrb, mrb_func_t func, mrb_int argc, const mrb_value *argv);
MRB_API mrb_value mrb_proc_cfunc_env_get(mrb_state *mrb, mrb_int idx);
/* old name */
#define mrb_cfunc_env_get(mrb, idx) mrb_proc_cfunc_env_get(mrb, idx)

#define MRB_METHOD_FUNC_FL    (1 << 24)
#define MRB_METHOD_PUBLIC_FL  0
#define MRB_METHOD_PRIVATE_FL (1 << 25)
#define MRB_METHOD_PROTECTED_FL (1 << 26)
#define MRB_METHOD_VDEFAULT_FL ((1 << 25) | (1 << 26))
#define MRB_METHOD_VISIBILITY_MASK ((1 << 25) | (1 << 26))

#define MRB_METHOD_FUNC_P(m) ((m).flags&MRB_METHOD_FUNC_FL)
#define MRB_METHOD_FUNC(m) ((m).as.func)
#define MRB_METHOD_FROM_FUNC(m,fn) do{(m).flags=MRB_METHOD_FUNC_FL;(m).as.func=(fn);}while(0)
#define MRB_METHOD_FROM_PROC(m,pr) do{(m).flags=0;(m).as.proc=(pr);}while(0)
#define MRB_METHOD_PROC_P(m) (!MRB_METHOD_FUNC_P(m))
#define MRB_METHOD_PROC(m) ((m).as.proc)
#define MRB_METHOD_UNDEF_P(m) ((m).as.proc==NULL)
#define MRB_METHOD_VISIBILITY(m) ((m).flags & MRB_METHOD_VISIBILITY_MASK)
#define MRB_SET_VISIBILITY_FLAGS(f,v) ((f)=(((f)&~MRB_METHOD_VISIBILITY_MASK)|(v)))
#define MRB_METHOD_SET_VISIBILITY(m,v) MRB_SET_VISIBILITY_FLAGS((m).flags,(v))

#define MRB_METHOD_CFUNC_P(m) (MRB_METHOD_FUNC_P(m) || (MRB_METHOD_PROC(m)?(MRB_PROC_CFUNC_P(MRB_METHOD_PROC(m))):FALSE))
/* use MRB_METHOD_CFUNC(m) only when MRB_METHOD_CFUNC_P(m) is true */
#define MRB_METHOD_CFUNC(m) (MRB_METHOD_FUNC_P(m)?MRB_METHOD_FUNC(m):MRB_PROC_CFUNC(MRB_METHOD_PROC(m)))

MRB_API mrb_value mrb_load_proc(mrb_state *mrb, const struct RProc *proc);

/**
 *  It can be used to isolate top-level scopes referenced by blocks generated by
 *  `mrb_load_string_cxt()` or similar called before entering the mruby VM (e.g. from `main()`).
 *  In that case, the `ci` parameter should be `mrb->c->cibase`.
 *
 *      #include <mruby.h>
 *      #include <mruby/compile.h>
 *      #include <mruby/proc.h>
 *
 *      int
 *      main(int argc, char **argv)
 *      {
 *        mrb_state *mrb;
 *        mrb_ccontext *cxt;
 *        mrb_value blk, ret;
 *
 *        mrb = mrb_open();
 *        cxt = mrb_ccontext_new(mrb);
 *        blk = mrb_load_string_cxt(mrb, "x, y, z = 1, 2, 3; proc { [x, y, z] }", cxt);
 *        mrb_vm_ci_env_clear(mrb, mrb->c->cibase);
 *        mrb_load_string_cxt(mrb, "x, y, z = 4, 5, 6", cxt);
 *        ret = mrb_funcall(mrb, blk, "call", 0);
 *        mrb_p(mrb, ret);  // => [1, 2, 3]
 *                          // => [4, 5, 6] if `mrb_vm_ci_env_clear()` is commented out
 *        mrb_ccontext_free(mrb, cxt);
 *        mrb_close(mrb);
 *
 *        return 0;
 *      }
 *
 *  The top-level local variable names stored in `mrb_ccontext` are retained.
 *  Use also `mrb_ccontext_cleanup_local_variables()` at the same time, if necessary.
 */
MRB_API void mrb_vm_ci_env_clear(mrb_state *mrb, mrb_callinfo *ci);

void mrb_vm_ci_proc_set(mrb_callinfo *ci, const struct RProc *p);
struct RClass * mrb_vm_ci_target_class(const mrb_callinfo *ci);
void mrb_vm_ci_target_class_set(mrb_callinfo *ci, struct RClass *tc);
struct REnv * mrb_vm_ci_env(const mrb_callinfo *ci);
void mrb_vm_ci_env_set(mrb_callinfo *ci, struct REnv *e);

MRB_END_DECL

#endif  /* MRUBY_PROC_H */
