/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 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 <unistd.h> // for ssize_t
#include <string.h>

#include "py/mpconfig.h"
#if MICROPY_PY_COLLECTIONS_DEQUE

#include "py/runtime.h"

typedef struct _mp_obj_deque_t {
 mp_obj_base_t base;
 size_t alloc;
 size_t i_get;
 size_t i_put;
 mp_obj_t *items;
 uint32_t flags;
 #define FLAG_CHECK_OVERFLOW 1
} mp_obj_deque_t;

STATIC mp_obj_t deque_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 mp_arg_check_num(n_args, n_kw, 2, 3, false);

 /* Initialization from existing sequence is not supported, so an empty
 tuple must be passed as such. */
 if (args[0] != mp_const_empty_tuple) {
 mp_raise_ValueError(NULL);
 }

 // Protect against -1 leading to zero-length allocation and bad array access
 mp_int_t maxlen = mp_obj_get_int(args[1]);
 if (maxlen < 0) {
 mp_raise_ValueError(NULL);
 }

 mp_obj_deque_t *o = m_new_obj(mp_obj_deque_t);
 o->base.type = type;
 o->alloc = maxlen + 1;
 o->i_get = o->i_put = 0;
 o->items = m_new0(mp_obj_t, o->alloc);

 if (n_args > 2) {
 o->flags = mp_obj_get_int(args[2]);
 }

 return MP_OBJ_FROM_PTR(o);
}

STATIC mp_obj_t deque_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
 mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
 switch (op) {
 case MP_UNARY_OP_BOOL:
 return mp_obj_new_bool(self->i_get != self->i_put);
 case MP_UNARY_OP_LEN: {
 ssize_t len = self->i_put - self->i_get;
 if (len < 0) {
 len += self->alloc;
 }
 return MP_OBJ_NEW_SMALL_INT(len);
 }
 #if MICROPY_PY_SYS_GETSIZEOF
 case MP_UNARY_OP_SIZEOF: {
 size_t sz = sizeof(*self) + sizeof(mp_obj_t) * self->alloc;
 return MP_OBJ_NEW_SMALL_INT(sz);
 }
 #endif
 default:
 return MP_OBJ_NULL; // op not supported
 }
}

STATIC mp_obj_t mp_obj_deque_append(mp_obj_t self_in, mp_obj_t arg) {
 mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);

 size_t new_i_put = self->i_put + 1;
 if (new_i_put == self->alloc) {
 new_i_put = 0;
 }

 if (self->flags & FLAG_CHECK_OVERFLOW && new_i_put == self->i_get) {
 mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("full"));
 }

 self->items[self->i_put] = arg;
 self->i_put = new_i_put;

 if (self->i_get == new_i_put) {
 if (++self->i_get == self->alloc) {
 self->i_get = 0;
 }
 }

 return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(deque_append_obj, mp_obj_deque_append);

STATIC mp_obj_t deque_popleft(mp_obj_t self_in) {
 mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);

 if (self->i_get == self->i_put) {
 mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("empty"));
 }

 mp_obj_t ret = self->items[self->i_get];
 self->items[self->i_get] = MP_OBJ_NULL;

 if (++self->i_get == self->alloc) {
 self->i_get = 0;
 }

 return ret;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(deque_popleft_obj, deque_popleft);

#if 0
STATIC mp_obj_t deque_clear(mp_obj_t self_in) {
 mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
 self->i_get = self->i_put = 0;
 mp_seq_clear(self->items, 0, self->alloc, sizeof(*self->items));
 return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(deque_clear_obj, deque_clear);
#endif

STATIC const mp_rom_map_elem_t deque_locals_dict_table[] = {
 { MP_ROM_QSTR(MP_QSTR_append), MP_ROM_PTR(&deque_append_obj) },
 #if 0
 { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&deque_clear_obj) },
 #endif
 { MP_ROM_QSTR(MP_QSTR_popleft), MP_ROM_PTR(&deque_popleft_obj) },
};

STATIC MP_DEFINE_CONST_DICT(deque_locals_dict, deque_locals_dict_table);

const mp_obj_type_t mp_type_deque = {
 { &mp_type_type },
 .name = MP_QSTR_deque,
 .make_new = deque_make_new,
 .unary_op = deque_unary_op,
 .locals_dict = (mp_obj_dict_t *)&deque_locals_dict,
};

#endif // MICROPY_PY_COLLECTIONS_DEQUE