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

#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "mpqstr.h"
#include "obj.h"
#include "map.h"
#include "runtime0.h"
#include "runtime.h"

typedef struct _mp_obj_list_t {
    mp_obj_base_t base;
    machine_uint_t alloc;
    machine_uint_t len;
    mp_obj_t *items;
} mp_obj_list_t;

static mp_obj_t mp_obj_new_list_iterator(mp_obj_list_t *list, int cur);
static mp_obj_list_t *list_new(uint n);
static mp_obj_t list_extend(mp_obj_t self_in, mp_obj_t arg_in);

/******************************************************************************/
/* list                                                                       */

static void list_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in) {
    mp_obj_list_t *o = o_in;
    print(env, "[");
    for (int i = 0; i < o->len; i++) {
        if (i > 0) {
            print(env, ", ");
        }
        mp_obj_print_helper(print, env, o->items[i]);
    }
    print(env, "]");
}

static mp_obj_t list_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args) {
    switch (n_args) {
        case 0:
            // return a new, empty list
            return rt_build_list(0, NULL);

        case 1:
        {
            // make list from iterable
            mp_obj_t iterable = rt_getiter(args[0]);
            mp_obj_t list = rt_build_list(0, NULL);
            mp_obj_t item;
            while ((item = rt_iternext(iterable)) != mp_const_stop_iteration) {
                rt_list_append(list, item);
            }
            return list;
        }

        default:
            nlr_jump(mp_obj_new_exception_msg_1_arg(MP_QSTR_TypeError, "list takes at most 1 argument, %d given", (void*)(machine_int_t)n_args));
    }
    return NULL;
}

static mp_obj_t list_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
    mp_obj_list_t *o = lhs;
    switch (op) {
        case RT_BINARY_OP_SUBSCR:
        {
            // list load
            uint index = mp_get_index(o->base.type, o->len, rhs);
            return o->items[index];
        }
        case RT_BINARY_OP_ADD:
        {
            if (!MP_OBJ_IS_TYPE(rhs, &list_type)) {
                return NULL;
            }
            mp_obj_list_t *p = rhs;
            mp_obj_list_t *s = list_new(o->len + p->len);
            memcpy(s->items, o->items, sizeof(mp_obj_t) * o->len);
            memcpy(s->items + o->len, p->items, sizeof(mp_obj_t) * p->len);
            return s;
        }
        case RT_BINARY_OP_INPLACE_ADD:
        {
            if (!MP_OBJ_IS_TYPE(rhs, &list_type)) {
                return NULL;
            }
            list_extend(lhs, rhs);
            return o;
        }
        case RT_BINARY_OP_MULTIPLY:
        {
            if (!MP_OBJ_IS_SMALL_INT(rhs)) {
                return NULL;
            }
            int n = MP_OBJ_SMALL_INT_VALUE(rhs);
            int len = o->len;
            mp_obj_list_t *s = list_new(len * n);
            mp_obj_t *dest = s->items;
            for (int i = 0; i < n; i++) {
                memcpy(dest, o->items, sizeof(mp_obj_t) * len);
                dest += len;
            }
            return s;
        }
        default:
            // op not supported
            return NULL;
    }
}

static mp_obj_t list_getiter(mp_obj_t o_in) {
    return mp_obj_new_list_iterator(o_in, 0);
}

mp_obj_t mp_obj_list_append(mp_obj_t self_in, mp_obj_t arg) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;
    if (self->len >= self->alloc) {
        self->items = m_renew(mp_obj_t, self->items, self->alloc, self->alloc * 2);
        self->alloc *= 2;
    }
    self->items[self->len++] = arg;
    return mp_const_none; // return None, as per CPython
}

static mp_obj_t list_extend(mp_obj_t self_in, mp_obj_t arg_in) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    assert(MP_OBJ_IS_TYPE(arg_in, &list_type));
    mp_obj_list_t *self = self_in;
    mp_obj_list_t *arg = arg_in;

    if (self->len + arg->len > self->alloc) {
        // TODO: use alloc policy for "4"
        self->items = m_renew(mp_obj_t, self->items, self->alloc, self->len + arg->len + 4);
        self->alloc = self->len + arg->len + 4;
    }

    memcpy(self->items + self->len, arg->items, sizeof(mp_obj_t) * arg->len);
    self->len += arg->len;
    return mp_const_none; // return None, as per CPython
}

static mp_obj_t list_pop(int n_args, const mp_obj_t *args) {
    assert(1 <= n_args && n_args <= 2);
    assert(MP_OBJ_IS_TYPE(args[0], &list_type));
    mp_obj_list_t *self = args[0];
    if (self->len == 0) {
        nlr_jump(mp_obj_new_exception_msg(MP_QSTR_IndexError, "pop from empty list"));
    }
    uint index = mp_get_index(self->base.type, self->len, n_args == 1 ? mp_obj_new_int(-1) : args[1]);
    mp_obj_t ret = self->items[index];
    self->len -= 1;
    memcpy(self->items + index, self->items + index + 1, (self->len - index) * sizeof(mp_obj_t));
    if (self->alloc > 2 * self->len) {
        self->items = m_renew(mp_obj_t, self->items, self->alloc, self->alloc/2);
        self->alloc /= 2;
    }
    return ret;
}

// TODO make this conform to CPython's definition of sort
static void mp_quicksort(mp_obj_t *head, mp_obj_t *tail, mp_obj_t key_fn, bool reversed) {
    int op = reversed ? RT_COMPARE_OP_MORE : RT_COMPARE_OP_LESS;
    while (head < tail) {
        mp_obj_t *h = head - 1;
        mp_obj_t *t = tail;
        mp_obj_t v = key_fn == NULL ? tail[0] : rt_call_function_1(key_fn, tail[0]); // get pivot using key_fn
        for (;;) {
            do ++h; while (rt_binary_op(op, key_fn == NULL ? h[0] : rt_call_function_1(key_fn, h[0]), v) == mp_const_true);
            do --t; while (h < t && rt_binary_op(op, v, key_fn == NULL ? t[0] : rt_call_function_1(key_fn, t[0])) == mp_const_true);
            if (h >= t) break;
            mp_obj_t x = h[0];
            h[0] = t[0];
            t[0] = x;
        }
        mp_obj_t x = h[0];
        h[0] = tail[0];
        tail[0] = x;
        mp_quicksort(head, t, key_fn, reversed);
        head = h + 1;
    }
}

static mp_obj_t list_sort(mp_obj_t args, mp_map_t *kwargs) {
    mp_obj_t *args_items = NULL;
    uint args_len = 0;

    assert(MP_OBJ_IS_TYPE(args, &tuple_type));
    mp_obj_tuple_get(args, &args_len, &args_items);
    assert(args_len >= 1);
    if (args_len > 1) {
        nlr_jump(mp_obj_new_exception_msg(MP_QSTR_TypeError,
                                          "list.sort takes no positional arguments"));
    }
    mp_obj_list_t *self = args_items[0];
    if (self->len > 1) {
        mp_map_elem_t *keyfun = mp_map_lookup(kwargs, MP_OBJ_NEW_QSTR(qstr_from_str_static("key")), MP_MAP_LOOKUP);
        mp_map_elem_t *reverse = mp_map_lookup(kwargs, MP_OBJ_NEW_QSTR(qstr_from_str_static("reverse")), MP_MAP_LOOKUP);
        mp_quicksort(self->items, self->items + self->len - 1,
                     keyfun ? keyfun->value : NULL,
                     reverse && reverse->value ? rt_is_true(reverse->value) : false);
    }
    return mp_const_none; // return None, as per CPython
}

static mp_obj_t list_clear(mp_obj_t self_in) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;
    self->len = 0;
    self->items = m_renew(mp_obj_t, self->items, self->alloc, 4);
    self->alloc = 4;
    return mp_const_none;
}

static mp_obj_t list_copy(mp_obj_t self_in) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;
    return mp_obj_new_list(self->len, self->items);
}

static mp_obj_t list_count(mp_obj_t self_in, mp_obj_t value) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;
    int count = 0;
    for (int i = 0; i < self->len; i++) {
         if (mp_obj_equal(self->items[i], value)) {
              count++;
         }
    }

    return mp_obj_new_int(count);
}

static mp_obj_t list_index(int n_args, const mp_obj_t *args) {
    assert(2 <= n_args && n_args <= 4);
    assert(MP_OBJ_IS_TYPE(args[0], &list_type));
    mp_obj_list_t *self = args[0];
    mp_obj_t *value = args[1];
    uint start = 0;
    uint stop = self->len;

    if (n_args >= 3) {
        start = mp_get_index(self->base.type, self->len, args[2]);
        if (n_args >= 4) {
            stop = mp_get_index(self->base.type, self->len, args[3]);
        }
    }

    for (uint i = start; i < stop; i++) {
         if (mp_obj_equal(self->items[i], value)) {
              return mp_obj_new_int(i);
         }
    }

    nlr_jump(mp_obj_new_exception_msg(MP_QSTR_ValueError, "object not in list"));
}

static mp_obj_t list_insert(mp_obj_t self_in, mp_obj_t idx, mp_obj_t obj) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;
    // insert has its own strange index logic
    int index = MP_OBJ_SMALL_INT_VALUE(idx);
    if (index < 0) {
         index += self->len;
    }
    if (index < 0) {
         index = 0;
    }
    if (index > self->len) {
         index = self->len;
    }

    mp_obj_list_append(self_in, mp_const_none);

    for (int i = self->len-1; i > index; i--) {
         self->items[i] = self->items[i-1];
    }
    self->items[index] = obj;

    return mp_const_none;
}

static mp_obj_t list_remove(mp_obj_t self_in, mp_obj_t value) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_t args[] = {self_in, value};
    args[1] = list_index(2, args);
    list_pop(2, args);

    return mp_const_none;
}

static mp_obj_t list_reverse(mp_obj_t self_in) {
    assert(MP_OBJ_IS_TYPE(self_in, &list_type));
    mp_obj_list_t *self = self_in;

    int len = self->len;
    for (int i = 0; i < len/2; i++) {
         mp_obj_t *a = self->items[i];
         self->items[i] = self->items[len-i-1];
         self->items[len-i-1] = a;
    }

    return mp_const_none;
}

static MP_DEFINE_CONST_FUN_OBJ_2(list_append_obj, mp_obj_list_append);
static MP_DEFINE_CONST_FUN_OBJ_2(list_extend_obj, list_extend);
static MP_DEFINE_CONST_FUN_OBJ_1(list_clear_obj, list_clear);
static MP_DEFINE_CONST_FUN_OBJ_1(list_copy_obj, list_copy);
static MP_DEFINE_CONST_FUN_OBJ_2(list_count_obj, list_count);
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(list_index_obj, 2, 4, list_index);
static MP_DEFINE_CONST_FUN_OBJ_3(list_insert_obj, list_insert);
static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(list_pop_obj, 1, 2, list_pop);
static MP_DEFINE_CONST_FUN_OBJ_2(list_remove_obj, list_remove);
static MP_DEFINE_CONST_FUN_OBJ_1(list_reverse_obj, list_reverse);
static MP_DEFINE_CONST_FUN_OBJ_KW(list_sort_obj, list_sort);

static const mp_method_t list_type_methods[] = {
    { "append", &list_append_obj },
    { "clear", &list_clear_obj },
    { "copy", &list_copy_obj },
    { "count", &list_count_obj },
    { "extend", &list_extend_obj },
    { "index", &list_index_obj },
    { "insert", &list_insert_obj },
    { "pop", &list_pop_obj },
    { "remove", &list_remove_obj },
    { "reverse", &list_reverse_obj },
    { "sort", &list_sort_obj },
    { NULL, NULL }, // end-of-list sentinel
};

const mp_obj_type_t list_type = {
    { &mp_const_type },
    "list",
    .print = list_print,
    .make_new = list_make_new,
    .binary_op = list_binary_op,
    .getiter = list_getiter,
    .methods = list_type_methods,
};

static mp_obj_list_t *list_new(uint n) {
    mp_obj_list_t *o = m_new_obj(mp_obj_list_t);
    o->base.type = &list_type;
    o->alloc = n < 4 ? 4 : n;
    o->len = n;
    o->items = m_new(mp_obj_t, o->alloc);
    return o;
}

mp_obj_t mp_obj_new_list(uint n, mp_obj_t *items) {
    mp_obj_list_t *o = list_new(n);
    for (int i = 0; i < n; i++) {
        o->items[i] = items[i];
    }
    return o;
}

mp_obj_t mp_obj_new_list_reverse(uint n, mp_obj_t *items) {
    mp_obj_list_t *o = list_new(n);
    for (int i = 0; i < n; i++) {
        o->items[i] = items[n - i - 1];
    }
    return o;
}

void mp_obj_list_get(mp_obj_t self_in, uint *len, mp_obj_t **items) {
    mp_obj_list_t *self = self_in;
    *len = self->len;
    *items = self->items;
}

void mp_obj_list_store(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
    mp_obj_list_t *self = self_in;
    uint i = mp_get_index(self->base.type, self->len, index);
    self->items[i] = value;
}

/******************************************************************************/
/* list iterator                                                              */

typedef struct _mp_obj_list_it_t {
    mp_obj_base_t base;
    mp_obj_list_t *list;
    machine_uint_t cur;
} mp_obj_list_it_t;

mp_obj_t list_it_iternext(mp_obj_t self_in) {
    mp_obj_list_it_t *self = self_in;
    if (self->cur < self->list->len) {
        mp_obj_t o_out = self->list->items[self->cur];
        self->cur += 1;
        return o_out;
    } else {
        return mp_const_stop_iteration;
    }
}

static const mp_obj_type_t list_it_type = {
    { &mp_const_type },
    "list_iterator",
    .iternext = list_it_iternext,
};

mp_obj_t mp_obj_new_list_iterator(mp_obj_list_t *list, int cur) {
    mp_obj_list_it_t *o = m_new_obj(mp_obj_list_it_t);
    o->base.type = &list_it_type;
    o->list = list;
    o->cur = cur;
    return o;
}