/*
MIT License

Copyright (c) 2022 Mikel Irazabal

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 "seq_arr.h"

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

static const size_t MIN_SIZE = 8;

static void maybe_expand(seq_arr_t* arr)
{
  if (arr->size + 1 == arr->cap) {
    arr->data = realloc(arr->data, 2 * arr->cap * arr->elt_size);
    assert(arr->data != NULL && "realloc failed to allocate memory");
    arr->cap *= 2;
  }
}

static void maybe_shrink(seq_arr_t* arr)
{
  const float occ = (float)arr->size / (float)arr->cap;
  if (arr->size > MIN_SIZE && occ < 0.25) {
    assert(arr->cap > MIN_SIZE);
    seq_arr_t tmp = {.data = NULL, .size = arr->size, .elt_size = arr->elt_size, .cap = arr->cap / 2};
    tmp.data = calloc(tmp.cap, tmp.cap);
    assert(tmp.data != NULL && "Memory exhausted");
    assert(arr->size <= tmp.cap);
    memcpy(tmp.data, arr->data, arr->size * arr->elt_size);
    free(arr->data);
    memcpy(arr, &tmp, sizeof(seq_arr_t));
  }
}

void seq_arr_init(seq_arr_t* arr, size_t elt_size) //__attribute__(malloc)
{
  assert(arr != NULL);
  seq_arr_t tmp = {.data = NULL, .size = 0, .elt_size = elt_size, .cap = MIN_SIZE};
  memcpy(arr, &tmp, sizeof(seq_arr_t));
  arr->data = calloc(arr->cap, elt_size);
  assert(arr->data != NULL);
}

void seq_arr_free(seq_arr_t* arr, void (*free_func)(void*))
{
  assert(arr != NULL);
  assert(arr->data != NULL);

  if (free_func != NULL) {
    void* start_it = seq_arr_front(arr);
    void* end_it = seq_arr_end(arr);
    while (start_it != end_it) {
      free_func(start_it);
      start_it = seq_arr_next(arr, start_it);
    }
  }

  free(arr->data);
}

void seq_arr_push_back(seq_arr_t* arr, void* data, size_t len)
{
  assert(arr != NULL);
  assert(arr->data != NULL);
  // assert(data != NULL);
  assert(len == arr->elt_size);

  maybe_expand(arr);

  const size_t offset = arr->size * arr->elt_size;
  memcpy(&arr->data[offset], data, arr->elt_size);
  arr->size += 1;
}

void seq_arr_erase(seq_arr_t* arr, void* start_it)
{
  // start_it must be in the range of arr->data
  assert(arr != NULL);
  assert(start_it != NULL);
  return seq_arr_erase_deep(arr, start_it, NULL);
}

void seq_arr_erase_deep(seq_arr_t* arr, void* start_it, void (*free_func)(void* it))
{
  // start_it must be in the range of arr->data
  assert(arr != NULL);
  assert(start_it != NULL);
  return seq_arr_erase_it(arr, start_it, seq_arr_next(arr, start_it), free_func);
}

void seq_arr_erase_it(seq_arr_t* arr, void* start_it, void* end_it, void (*free_func)(void* it))
{
  // start_it && end_it must be in the range of arr->data
  assert(arr != NULL);
  assert(start_it != NULL);
  assert(end_it != NULL);
  assert(end_it >= start_it);

  if (start_it == end_it)
    return;

  if (free_func != NULL) {
    void* it = start_it;
    while (it != end_it) {
      free_func(it);
      it = seq_arr_next(arr, it);
    }
  }

  const int num_bytes_move = seq_arr_end(arr) - end_it;
  assert(num_bytes_move > -1);
  memmove(start_it, end_it, num_bytes_move);

  const int num_bytes_erase = end_it - start_it;
  const int32_t num_elm_erase = num_bytes_erase / arr->elt_size;
  assert(num_elm_erase > 0);
  arr->size -= num_elm_erase;

  memset(seq_arr_end(arr), 0, num_bytes_erase);

  maybe_shrink(arr);
}

size_t seq_arr_size(seq_arr_t const* arr)
{
  assert(arr != NULL);
  return arr->size;
}

void* seq_arr_front(seq_arr_t const* arr)
{
  assert(arr != NULL);
  return arr->data;
}

void* seq_arr_next(seq_arr_t const* arr, void const* it)
{
  assert(arr != NULL);
  assert(it != NULL);
  return (uint8_t*)it + arr->elt_size;
}

void* seq_arr_end(seq_arr_t const* arr)
{
  assert(arr != NULL);
  assert(arr->data != NULL);
  return &arr->data[arr->size * arr->elt_size];
}

void* seq_arr_at(seq_arr_t const* arr, uint32_t pos)
{
  assert(arr != NULL);
  assert(arr->data != NULL);
  assert(pos < arr->size);
  return arr->data + pos * arr->elt_size;
}

ptrdiff_t seq_arr_dist(seq_arr_t const* arr, void const* first, void const* last)
{
  assert(arr != NULL);
  assert(first != NULL);
  assert(last != NULL);
  const ptrdiff_t pos = (last - first) / arr->elt_size;
  assert(pos > -1);
  return pos;
}