/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 * Copyright (c) 2014 Paul Sokolovsky
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <string.h>
#include <assert.h>

#include "py/objtuple.h"
#include "py/objfun.h"
#include "py/runtime.h"
#include "py/bc.h"
#include "py/stackctrl.h"

#if MICROPY_DEBUG_VERBOSE // print debugging info
#define DEBUG_PRINT (1)
#else // don't print debugging info
#define DEBUG_PRINT (0)
#define DEBUG_printf(...) (void)0
#endif

// Note: the "name" entry in mp_obj_type_t for a function type must be
// MP_QSTR_function because it is used to determine if an object is of generic
// function type.

/******************************************************************************/
/* builtin functions */

STATIC mp_obj_t fun_builtin_0_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 (void)args;
 assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin_0));
 mp_obj_fun_builtin_fixed_t *self = MP_OBJ_TO_PTR(self_in);
 mp_arg_check_num(n_args, n_kw, 0, 0, false);
 return self->fun._0();
}

const mp_obj_type_t mp_type_fun_builtin_0 = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_builtin_0_call,
 .unary_op = mp_generic_unary_op,
};

STATIC mp_obj_t fun_builtin_1_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin_1));
 mp_obj_fun_builtin_fixed_t *self = MP_OBJ_TO_PTR(self_in);
 mp_arg_check_num(n_args, n_kw, 1, 1, false);
 return self->fun._1(args[0]);
}

const mp_obj_type_t mp_type_fun_builtin_1 = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_builtin_1_call,
 .unary_op = mp_generic_unary_op,
};

STATIC mp_obj_t fun_builtin_2_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin_2));
 mp_obj_fun_builtin_fixed_t *self = MP_OBJ_TO_PTR(self_in);
 mp_arg_check_num(n_args, n_kw, 2, 2, false);
 return self->fun._2(args[0], args[1]);
}

const mp_obj_type_t mp_type_fun_builtin_2 = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_builtin_2_call,
 .unary_op = mp_generic_unary_op,
};

STATIC mp_obj_t fun_builtin_3_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin_3));
 mp_obj_fun_builtin_fixed_t *self = MP_OBJ_TO_PTR(self_in);
 mp_arg_check_num(n_args, n_kw, 3, 3, false);
 return self->fun._3(args[0], args[1], args[2]);
}

const mp_obj_type_t mp_type_fun_builtin_3 = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_builtin_3_call,
 .unary_op = mp_generic_unary_op,
};

STATIC mp_obj_t fun_builtin_var_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin_var));
 mp_obj_fun_builtin_var_t *self = MP_OBJ_TO_PTR(self_in);

 // check number of arguments
 mp_arg_check_num(n_args, n_kw, self->n_args_min, self->n_args_max, self->is_kw);

 if (self->is_kw) {
 // function allows keywords

 // we create a map directly from the given args array
 mp_map_t kw_args;
 mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);

 return self->fun.kw(n_args, args, &kw_args);

 } else {
 // function takes a variable number of arguments, but no keywords

 return self->fun.var(n_args, args);
 }
}

const mp_obj_type_t mp_type_fun_builtin_var = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_builtin_var_call,
 .unary_op = mp_generic_unary_op,
};

/******************************************************************************/
/* byte code functions */

qstr mp_obj_code_get_name(const byte *code_info) {
 code_info = mp_decode_uint_skip(code_info); // skip code_info_size entry
 #if MICROPY_PERSISTENT_CODE
 return code_info[0] | (code_info[1] << 8);
 #else
 return mp_decode_uint_value(code_info);
 #endif
}

#if MICROPY_EMIT_NATIVE
STATIC const mp_obj_type_t mp_type_fun_native;
#endif

qstr mp_obj_fun_get_name(mp_const_obj_t fun_in) {
 const mp_obj_fun_bc_t *fun = MP_OBJ_TO_PTR(fun_in);
 #if MICROPY_EMIT_NATIVE
 if (fun->base.type == &mp_type_fun_native) {
 // TODO native functions don't have name stored
 return MP_QSTR_;
 }
 #endif

 const byte *bc = fun->bytecode;
 bc = mp_decode_uint_skip(bc); // skip n_state
 bc = mp_decode_uint_skip(bc); // skip n_exc_stack
 bc++; // skip scope_params
 bc++; // skip n_pos_args
 bc++; // skip n_kwonly_args
 bc++; // skip n_def_pos_args
 return mp_obj_code_get_name(bc);
}

#if MICROPY_CPYTHON_COMPAT
STATIC void fun_bc_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
 (void)kind;
 mp_obj_fun_bc_t *o = MP_OBJ_TO_PTR(o_in);
 mp_printf(print, "<function %q at 0x%p>", mp_obj_fun_get_name(o_in), o);
}
#endif

#if DEBUG_PRINT
STATIC void dump_args(const mp_obj_t *a, size_t sz) {
 DEBUG_printf("%p: ", a);
 for (size_t i = 0; i < sz; i++) {
 DEBUG_printf("%p ", a[i]);
 }
 DEBUG_printf("\n");
}
#else
#define dump_args(...) (void)0
#endif

// With this macro you can tune the maximum number of function state bytes
// that will be allocated on the stack. Any function that needs more
// than this will try to use the heap, with fallback to stack allocation.
#define VM_MAX_STATE_ON_STACK (11 * sizeof(mp_uint_t))

// Set this to 1 to enable a simple stack overflow check.
#define VM_DETECT_STACK_OVERFLOW (0)

#define DECODE_CODESTATE_SIZE(bytecode, n_state_out_var, state_size_out_var) \
 { \
/* bytecode prelude: state size and exception stack size */ \
 n_state_out_var = mp_decode_uint_value(bytecode); \
 size_t n_exc_stack = mp_decode_uint_value(mp_decode_uint_skip(bytecode)); \
 \
 n_state += VM_DETECT_STACK_OVERFLOW; \
 \
/* state size in bytes */ \
 state_size_out_var = n_state * sizeof(mp_obj_t) + n_exc_stack * sizeof(mp_exc_stack_t); \
 }

#define INIT_CODESTATE(code_state, _fun_bc, n_args, n_kw, args) \
 code_state->fun_bc = _fun_bc; \
 code_state->ip = 0; \
 mp_setup_code_state(code_state, n_args, n_kw, args); \
 code_state->old_globals = mp_globals_get();

#if MICROPY_STACKLESS
mp_code_state_t *mp_obj_fun_bc_prepare_codestate(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 MP_STACK_CHECK();
 mp_obj_fun_bc_t *self = MP_OBJ_TO_PTR(self_in);

 size_t n_state, state_size;
 DECODE_CODESTATE_SIZE(self->bytecode, n_state, state_size);

 mp_code_state_t *code_state;
 #if MICROPY_ENABLE_PYSTACK
 code_state = mp_pystack_alloc(sizeof(mp_code_state_t) + state_size);
 #else
 // If we use m_new_obj_var(), then on no memory, MemoryError will be
 // raised. But this is not correct exception for a function call,
 // RuntimeError should be raised instead. So, we use m_new_obj_var_maybe(),
 // return NULL, then vm.c takes the needed action (either raise
 // RuntimeError or fallback to stack allocation).
 code_state = m_new_obj_var_maybe(mp_code_state_t, byte, state_size);
 if (!code_state) {
 return NULL;
 }
 #endif

 INIT_CODESTATE(code_state, self, n_args, n_kw, args);

 // execute the byte code with the correct globals context
 mp_globals_set(self->globals);

 return code_state;
}
#endif

STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 MP_STACK_CHECK();

 DEBUG_printf("Input n_args: " UINT_FMT ", n_kw: " UINT_FMT "\n", n_args, n_kw);
 DEBUG_printf("Input pos args: ");
 dump_args(args, n_args);
 DEBUG_printf("Input kw args: ");
 dump_args(args + n_args, n_kw * 2);
 mp_obj_fun_bc_t *self = MP_OBJ_TO_PTR(self_in);
 DEBUG_printf("Func n_def_args: %d\n", self->n_def_args);

 size_t n_state, state_size;
 DECODE_CODESTATE_SIZE(self->bytecode, n_state, state_size);

 // allocate state for locals and stack
 mp_code_state_t *code_state = NULL;
 #if MICROPY_ENABLE_PYSTACK
 code_state = mp_pystack_alloc(sizeof(mp_code_state_t) + state_size);
 #else
 if (state_size > VM_MAX_STATE_ON_STACK) {
 code_state = m_new_obj_var_maybe(mp_code_state_t, byte, state_size);
 }
 if (code_state == NULL) {
 code_state = alloca(sizeof(mp_code_state_t) + state_size);
 state_size = 0; // indicate that we allocated using alloca
 }
 #endif

 INIT_CODESTATE(code_state, self, n_args, n_kw, args);

 // execute the byte code with the correct globals context
 mp_globals_set(self->globals);
 mp_vm_return_kind_t vm_return_kind = mp_execute_bytecode(code_state, MP_OBJ_NULL);
 mp_globals_set(code_state->old_globals);

#if VM_DETECT_STACK_OVERFLOW
 if (vm_return_kind == MP_VM_RETURN_NORMAL) {
 if (code_state->sp < code_state->state) {
 printf("VM stack underflow: " INT_FMT "\n", code_state->sp - code_state->state);
 assert(0);
 }
 }
 // We can't check the case when an exception is returned in state[n_state - 1]
 // and there are no arguments, because in this case our detection slot may have
 // been overwritten by the returned exception (which is allowed).
 if (!(vm_return_kind == MP_VM_RETURN_EXCEPTION && self->n_pos_args + self->n_kwonly_args == 0)) {
 // Just check to see that we have at least 1 null object left in the state.
 bool overflow = true;
 for (size_t i = 0; i < n_state - self->n_pos_args - self->n_kwonly_args; i++) {
 if (code_state->state[i] == MP_OBJ_NULL) {
 overflow = false;
 break;
 }
 }
 if (overflow) {
 printf("VM stack overflow state=%p n_state+1=" UINT_FMT "\n", code_state->state, n_state);
 assert(0);
 }
 }
#endif

 mp_obj_t result;
 if (vm_return_kind == MP_VM_RETURN_NORMAL) {
 // return value is in *sp
 result = *code_state->sp;
 } else {
 // must be an exception because normal functions can't yield
 assert(vm_return_kind == MP_VM_RETURN_EXCEPTION);
 // return value is in fastn[0]==state[n_state - 1]
 result = code_state->state[n_state - 1];
 }

 #if MICROPY_ENABLE_PYSTACK
 mp_pystack_free(code_state);
 #else
 // free the state if it was allocated on the heap
 if (state_size != 0) {
 m_del_var(mp_code_state_t, byte, state_size, code_state);
 }
 #endif

 if (vm_return_kind == MP_VM_RETURN_NORMAL) {
 return result;
 } else { // MP_VM_RETURN_EXCEPTION
 nlr_raise(result);
 }
}

#if MICROPY_PY_FUNCTION_ATTRS
STATIC void fun_bc_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
 if (dest[0] != MP_OBJ_NULL) {
 // not load attribute
 return;
 }
 if (attr == MP_QSTR___name__) {
 dest[0] = MP_OBJ_NEW_QSTR(mp_obj_fun_get_name(self_in));
 }
}
#endif

const mp_obj_type_t mp_type_fun_bc = {
 { &mp_type_type },
 .name = MP_QSTR_function,
#if MICROPY_CPYTHON_COMPAT
 .print = fun_bc_print,
#endif
 .call = fun_bc_call,
 .unary_op = mp_generic_unary_op,
#if MICROPY_PY_FUNCTION_ATTRS
 .attr = fun_bc_attr,
#endif
};

mp_obj_t mp_obj_new_fun_bc(mp_obj_t def_args_in, mp_obj_t def_kw_args, const byte *code, const mp_uint_t *const_table) {
 size_t n_def_args = 0;
 size_t n_extra_args = 0;
 mp_obj_tuple_t *def_args = MP_OBJ_TO_PTR(def_args_in);
 if (def_args_in != MP_OBJ_NULL) {
 assert(MP_OBJ_IS_TYPE(def_args_in, &mp_type_tuple));
 n_def_args = def_args->len;
 n_extra_args = def_args->len;
 }
 if (def_kw_args != MP_OBJ_NULL) {
 n_extra_args += 1;
 }
 mp_obj_fun_bc_t *o = m_new_obj_var(mp_obj_fun_bc_t, mp_obj_t, n_extra_args);
 o->base.type = &mp_type_fun_bc;
 o->globals = mp_globals_get();
 o->bytecode = code;
 o->const_table = const_table;
 if (def_args != NULL) {
 memcpy(o->extra_args, def_args->items, n_def_args * sizeof(mp_obj_t));
 }
 if (def_kw_args != MP_OBJ_NULL) {
 o->extra_args[n_def_args] = def_kw_args;
 }
 return MP_OBJ_FROM_PTR(o);
}

/******************************************************************************/
/* native functions */

#if MICROPY_EMIT_NATIVE

STATIC mp_obj_t fun_native_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 MP_STACK_CHECK();
 mp_obj_fun_bc_t *self = self_in;
 mp_call_fun_t fun = MICROPY_MAKE_POINTER_CALLABLE((void*)self->bytecode);
 return fun(self_in, n_args, n_kw, args);
}

STATIC const mp_obj_type_t mp_type_fun_native = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_native_call,
 .unary_op = mp_generic_unary_op,
};

mp_obj_t mp_obj_new_fun_native(mp_obj_t def_args_in, mp_obj_t def_kw_args, const void *fun_data, const mp_uint_t *const_table) {
 mp_obj_fun_bc_t *o = mp_obj_new_fun_bc(def_args_in, def_kw_args, (const byte*)fun_data, const_table);
 o->base.type = &mp_type_fun_native;
 return o;
}

#endif // MICROPY_EMIT_NATIVE

/******************************************************************************/
/* viper functions */

#if MICROPY_EMIT_NATIVE

typedef struct _mp_obj_fun_viper_t {
 mp_obj_base_t base;
 size_t n_args;
 void *fun_data; // GC must be able to trace this pointer
 mp_uint_t type_sig;
} mp_obj_fun_viper_t;

typedef mp_uint_t (*viper_fun_0_t)(void);
typedef mp_uint_t (*viper_fun_1_t)(mp_uint_t);
typedef mp_uint_t (*viper_fun_2_t)(mp_uint_t, mp_uint_t);
typedef mp_uint_t (*viper_fun_3_t)(mp_uint_t, mp_uint_t, mp_uint_t);
typedef mp_uint_t (*viper_fun_4_t)(mp_uint_t, mp_uint_t, mp_uint_t, mp_uint_t);

STATIC mp_obj_t fun_viper_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 mp_obj_fun_viper_t *self = self_in;

 mp_arg_check_num(n_args, n_kw, self->n_args, self->n_args, false);

 void *fun = MICROPY_MAKE_POINTER_CALLABLE(self->fun_data);

 mp_uint_t ret;
 if (n_args == 0) {
 ret = ((viper_fun_0_t)fun)();
 } else if (n_args == 1) {
 ret = ((viper_fun_1_t)fun)(mp_convert_obj_to_native(args[0], self->type_sig >> 4));
 } else if (n_args == 2) {
 ret = ((viper_fun_2_t)fun)(mp_convert_obj_to_native(args[0], self->type_sig >> 4), mp_convert_obj_to_native(args[1], self->type_sig >> 8));
 } else if (n_args == 3) {
 ret = ((viper_fun_3_t)fun)(mp_convert_obj_to_native(args[0], self->type_sig >> 4), mp_convert_obj_to_native(args[1], self->type_sig >> 8), mp_convert_obj_to_native(args[2], self->type_sig >> 12));
 } else {
 // compiler allows at most 4 arguments
 assert(n_args == 4);
 ret = ((viper_fun_4_t)fun)(
 mp_convert_obj_to_native(args[0], self->type_sig >> 4),
 mp_convert_obj_to_native(args[1], self->type_sig >> 8),
 mp_convert_obj_to_native(args[2], self->type_sig >> 12),
 mp_convert_obj_to_native(args[3], self->type_sig >> 16)
 );
 }

 return mp_convert_native_to_obj(ret, self->type_sig);
}

STATIC const mp_obj_type_t mp_type_fun_viper = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_viper_call,
 .unary_op = mp_generic_unary_op,
};

mp_obj_t mp_obj_new_fun_viper(size_t n_args, void *fun_data, mp_uint_t type_sig) {
 mp_obj_fun_viper_t *o = m_new_obj(mp_obj_fun_viper_t);
 o->base.type = &mp_type_fun_viper;
 o->n_args = n_args;
 o->fun_data = fun_data;
 o->type_sig = type_sig;
 return o;
}

#endif // MICROPY_EMIT_NATIVE

/******************************************************************************/
/* inline assembler functions */

#if MICROPY_EMIT_INLINE_ASM

typedef struct _mp_obj_fun_asm_t {
 mp_obj_base_t base;
 size_t n_args;
 void *fun_data; // GC must be able to trace this pointer
 mp_uint_t type_sig;
} mp_obj_fun_asm_t;

typedef mp_uint_t (*inline_asm_fun_0_t)(void);
typedef mp_uint_t (*inline_asm_fun_1_t)(mp_uint_t);
typedef mp_uint_t (*inline_asm_fun_2_t)(mp_uint_t, mp_uint_t);
typedef mp_uint_t (*inline_asm_fun_3_t)(mp_uint_t, mp_uint_t, mp_uint_t);
typedef mp_uint_t (*inline_asm_fun_4_t)(mp_uint_t, mp_uint_t, mp_uint_t, mp_uint_t);

// convert a MicroPython object to a sensible value for inline asm
STATIC mp_uint_t convert_obj_for_inline_asm(mp_obj_t obj) {
 // TODO for byte_array, pass pointer to the array
 if (MP_OBJ_IS_SMALL_INT(obj)) {
 return MP_OBJ_SMALL_INT_VALUE(obj);
 } else if (obj == mp_const_none) {
 return 0;
 } else if (obj == mp_const_false) {
 return 0;
 } else if (obj == mp_const_true) {
 return 1;
 } else if (MP_OBJ_IS_TYPE(obj, &mp_type_int)) {
 return mp_obj_int_get_truncated(obj);
 } else if (MP_OBJ_IS_STR(obj)) {
 // pointer to the string (it's probably constant though!)
 size_t l;
 return (mp_uint_t)mp_obj_str_get_data(obj, &l);
 } else {
 mp_obj_type_t *type = mp_obj_get_type(obj);
 if (0) {
#if MICROPY_PY_BUILTINS_FLOAT
 } else if (type == &mp_type_float) {
 // convert float to int (could also pass in float registers)
 return (mp_int_t)mp_obj_float_get(obj);
#endif
 } else if (type == &mp_type_tuple || type == &mp_type_list) {
 // pointer to start of tuple (could pass length, but then could use len(x) for that)
 size_t len;
 mp_obj_t *items;
 mp_obj_get_array(obj, &len, &items);
 return (mp_uint_t)items;
 } else {
 mp_buffer_info_t bufinfo;
 if (mp_get_buffer(obj, &bufinfo, MP_BUFFER_WRITE)) {
 // supports the buffer protocol, return a pointer to the data
 return (mp_uint_t)bufinfo.buf;
 } else {
 // just pass along a pointer to the object
 return (mp_uint_t)obj;
 }
 }
 }
}

STATIC mp_obj_t fun_asm_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 mp_obj_fun_asm_t *self = self_in;

 mp_arg_check_num(n_args, n_kw, self->n_args, self->n_args, false);

 void *fun = MICROPY_MAKE_POINTER_CALLABLE(self->fun_data);

 mp_uint_t ret;
 if (n_args == 0) {
 ret = ((inline_asm_fun_0_t)fun)();
 } else if (n_args == 1) {
 ret = ((inline_asm_fun_1_t)fun)(convert_obj_for_inline_asm(args[0]));
 } else if (n_args == 2) {
 ret = ((inline_asm_fun_2_t)fun)(convert_obj_for_inline_asm(args[0]), convert_obj_for_inline_asm(args[1]));
 } else if (n_args == 3) {
 ret = ((inline_asm_fun_3_t)fun)(convert_obj_for_inline_asm(args[0]), convert_obj_for_inline_asm(args[1]), convert_obj_for_inline_asm(args[2]));
 } else {
 // compiler allows at most 4 arguments
 assert(n_args == 4);
 ret = ((inline_asm_fun_4_t)fun)(
 convert_obj_for_inline_asm(args[0]),
 convert_obj_for_inline_asm(args[1]),
 convert_obj_for_inline_asm(args[2]),
 convert_obj_for_inline_asm(args[3])
 );
 }

 return mp_convert_native_to_obj(ret, self->type_sig);
}

STATIC const mp_obj_type_t mp_type_fun_asm = {
 { &mp_type_type },
 .name = MP_QSTR_function,
 .call = fun_asm_call,
 .unary_op = mp_generic_unary_op,
};

mp_obj_t mp_obj_new_fun_asm(size_t n_args, void *fun_data, mp_uint_t type_sig) {
 mp_obj_fun_asm_t *o = m_new_obj(mp_obj_fun_asm_t);
 o->base.type = &mp_type_fun_asm;
 o->n_args = n_args;
 o->fun_data = fun_data;
 o->type_sig = type_sig;
 return o;
}

#endif // MICROPY_EMIT_INLINE_ASM