/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 *
 * 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 <stdlib.h>

#include "py/runtime.h"

/******************************************************************************/
/* range iterator */

typedef struct _mp_obj_range_it_t {
 mp_obj_base_t base;
 // TODO make these values generic objects or something
 mp_int_t cur;
 mp_int_t stop;
 mp_int_t step;
} mp_obj_range_it_t;

STATIC mp_obj_t range_it_iternext(mp_obj_t o_in) {
 mp_obj_range_it_t *o = MP_OBJ_TO_PTR(o_in);
 if ((o->step > 0 && o->cur < o->stop) || (o->step < 0 && o->cur > o->stop)) {
 mp_obj_t o_out = MP_OBJ_NEW_SMALL_INT(o->cur);
 o->cur += o->step;
 return o_out;
 } else {
 return MP_OBJ_STOP_ITERATION;
 }
}

STATIC const mp_obj_type_t range_it_type = {
 { &mp_type_type },
 .name = MP_QSTR_iterator,
 .getiter = mp_identity_getiter,
 .iternext = range_it_iternext,
};

STATIC mp_obj_t mp_obj_new_range_iterator(mp_int_t cur, mp_int_t stop, mp_int_t step, mp_obj_iter_buf_t *iter_buf) {
 assert(sizeof(mp_obj_range_it_t) <= sizeof(mp_obj_iter_buf_t));
 mp_obj_range_it_t *o = (mp_obj_range_it_t *)iter_buf;
 o->base.type = &range_it_type;
 o->cur = cur;
 o->stop = stop;
 o->step = step;
 return MP_OBJ_FROM_PTR(o);
}

/******************************************************************************/
/* range */

typedef struct _mp_obj_range_t {
 mp_obj_base_t base;
 // TODO make these values generic objects or something
 mp_int_t start;
 mp_int_t stop;
 mp_int_t step;
} mp_obj_range_t;

STATIC void range_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
 (void)kind;
 mp_obj_range_t *self = MP_OBJ_TO_PTR(self_in);
 mp_printf(print, "range(" INT_FMT ", " INT_FMT "", self->start, self->stop);
 if (self->step == 1) {
 mp_print_str(print, ")");
 } else {
 mp_printf(print, ", " INT_FMT ")", self->step);
 }
}

STATIC mp_obj_t range_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, 1, 3, false);

 mp_obj_range_t *o = m_new_obj(mp_obj_range_t);
 o->base.type = type;
 o->start = 0;
 o->step = 1;

 if (n_args == 1) {
 o->stop = mp_obj_get_int(args[0]);
 } else {
 o->start = mp_obj_get_int(args[0]);
 o->stop = mp_obj_get_int(args[1]);
 if (n_args == 3) {
 o->step = mp_obj_get_int(args[2]);
 if (o->step == 0) {
 mp_raise_ValueError(MP_ERROR_TEXT("zero step"));
 }
 }
 }

 return MP_OBJ_FROM_PTR(o);
}

STATIC mp_int_t range_len(mp_obj_range_t *self) {
 // When computing length, need to take into account step!=1 and step<0.
 mp_int_t len = self->stop - self->start + self->step;
 if (self->step > 0) {
 len -= 1;
 } else {
 len += 1;
 }
 len = len / self->step;
 if (len < 0) {
 len = 0;
 }
 return len;
}

STATIC mp_obj_t range_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
 mp_obj_range_t *self = MP_OBJ_TO_PTR(self_in);
 mp_int_t len = range_len(self);
 switch (op) {
 case MP_UNARY_OP_BOOL:
 return mp_obj_new_bool(len > 0);
 case MP_UNARY_OP_LEN:
 return MP_OBJ_NEW_SMALL_INT(len);
 default:
 return MP_OBJ_NULL; // op not supported
 }
}

#if MICROPY_PY_BUILTINS_RANGE_BINOP
STATIC mp_obj_t range_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
 if (!mp_obj_is_type(rhs_in, &mp_type_range) || op != MP_BINARY_OP_EQUAL) {
 return MP_OBJ_NULL; // op not supported
 }
 mp_obj_range_t *lhs = MP_OBJ_TO_PTR(lhs_in);
 mp_obj_range_t *rhs = MP_OBJ_TO_PTR(rhs_in);
 mp_int_t lhs_len = range_len(lhs);
 mp_int_t rhs_len = range_len(rhs);
 return mp_obj_new_bool(
 lhs_len == rhs_len
 && (lhs_len == 0
 || (lhs->start == rhs->start
 && (lhs_len == 1 || lhs->step == rhs->step)))
 );
}
#endif

STATIC mp_obj_t range_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
 if (value == MP_OBJ_SENTINEL) {
 // load
 mp_obj_range_t *self = MP_OBJ_TO_PTR(self_in);
 mp_int_t len = range_len(self);
 #if MICROPY_PY_BUILTINS_SLICE
 if (mp_obj_is_type(index, &mp_type_slice)) {
 mp_bound_slice_t slice;
 mp_seq_get_fast_slice_indexes(len, index, &slice);
 mp_obj_range_t *o = m_new_obj(mp_obj_range_t);
 o->base.type = &mp_type_range;
 o->start = self->start + slice.start * self->step;
 o->stop = self->start + slice.stop * self->step;
 o->step = slice.step * self->step;
 if (slice.step < 0) {
 // Negative slice steps have inclusive stop, so adjust for exclusive
 o->stop -= self->step;
 }
 return MP_OBJ_FROM_PTR(o);
 }
 #endif
 size_t index_val = mp_get_index(self->base.type, len, index, false);
 return MP_OBJ_NEW_SMALL_INT(self->start + index_val * self->step);
 } else {
 return MP_OBJ_NULL; // op not supported
 }
}

STATIC mp_obj_t range_getiter(mp_obj_t o_in, mp_obj_iter_buf_t *iter_buf) {
 mp_obj_range_t *o = MP_OBJ_TO_PTR(o_in);
 return mp_obj_new_range_iterator(o->start, o->stop, o->step, iter_buf);
}


#if MICROPY_PY_BUILTINS_RANGE_ATTRS
STATIC void range_attr(mp_obj_t o_in, qstr attr, mp_obj_t *dest) {
 if (dest[0] != MP_OBJ_NULL) {
 // not load attribute
 return;
 }
 mp_obj_range_t *o = MP_OBJ_TO_PTR(o_in);
 if (attr == MP_QSTR_start) {
 dest[0] = mp_obj_new_int(o->start);
 } else if (attr == MP_QSTR_stop) {
 dest[0] = mp_obj_new_int(o->stop);
 } else if (attr == MP_QSTR_step) {
 dest[0] = mp_obj_new_int(o->step);
 }
}
#endif

const mp_obj_type_t mp_type_range = {
 { &mp_type_type },
 .name = MP_QSTR_range,
 .print = range_print,
 .make_new = range_make_new,
 .unary_op = range_unary_op,
 #if MICROPY_PY_BUILTINS_RANGE_BINOP
 .binary_op = range_binary_op,
 #endif
 .subscr = range_subscr,
 .getiter = range_getiter,
 #if MICROPY_PY_BUILTINS_RANGE_ATTRS
 .attr = range_attr,
 #endif
};