// vim:fileencoding=utf-8:foldmethod=marker

#include "./array.h"
#include "../../common/assert/assert.h"
#include "../mem/allocator/mem_allocator.h"
#include "../../common/misc/misc_utils.h"
#include "../../common/aliases/aliases.h"
#include <stddef.h>

#define _offset_pointer(PTR, OFFSET) ((void *)((uptr)(PTR) + (OFFSET)))
#define _array_header(ARRAY) (ArrayHeader *)(_offset_pointer(ARRAY, -sizeof(ArrayHeader)))

wapp_persist inline void _array_validate(const GenericArray array, u64 item_size);

u64 _array_count(GenericArray array) {
	wapp_debug_assert(array != NULL, "`array` should not be NULL");

	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(WAPP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");

	return header->count;
}

u64 _array_capacity(GenericArray array) {
	wapp_debug_assert(array != NULL, "`array` should not be NULL");

	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(WAPP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");

	return header->capacity;
}

u64 _array_item_size(GenericArray array) {
	wapp_debug_assert(array != NULL, "`array` should not be NULL");

	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(WAPP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");

	return header->item_size;
}

void _array_set_count(GenericArray array, u64 count) {
	wapp_debug_assert(array != NULL, "`array` should not be NULL");

	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(WAPP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");

	header->count = count;
}

void *_array_get(GenericArray array, u64 index, u64 item_size) {
	wapp_runtime_assert(array != NULL, "`array` should not be NULL");
	_array_validate(array, item_size);

	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(index < header->count, "`index` is out of bounds");

	return _offset_pointer(array, header->item_size * index);
}

void _array_set(GenericArray array, u64 index, void *value, u64 item_size) {
	void *item = _array_get(array, index, item_size);

	ArrayHeader *header = _array_header(array);
	memcpy(item, value, header->item_size);
}

void _array_append_capped(GenericArray array, void *value, u64 item_size) {
	wapp_runtime_assert(array != NULL, "`array` should not be NULL");
	_array_validate(array, item_size);

	ArrayHeader *header = _array_header(array);
	if (header->count >= header->capacity) { return; }

	u64 index = (header->count)++;
	_array_set(array, index, value, item_size);
}

void _array_extend_capped(GenericArray dst, const GenericArray src, u64 item_size) {
	wapp_runtime_assert(dst != NULL && src != NULL, "`dst` and `src` should not be NULL");
	_array_validate(dst, item_size);
	_array_validate(src, item_size);

	ArrayHeader *src_header = _array_header(src);
	ArrayHeader *dst_header = _array_header(dst);
	u64 remaining_capacity = dst_header->capacity - dst_header->count;

	u64 copy_count = src_header->count < remaining_capacity ? src_header->count : remaining_capacity;
	void *dst_ptr  = _offset_pointer(dst, dst_header->count * dst_header->item_size);
	memcpy(dst_ptr, src, copy_count * src_header->item_size);
	dst_header->count += copy_count;
}

void _array_copy_capped(GenericArray dst, const GenericArray src, u64 item_size) {
	wapp_runtime_assert(dst != NULL && src != NULL, "`dst` and `src` should not be NULL");
	_array_validate(dst, item_size);
	_array_validate(src, item_size);

	_array_clear(dst, item_size);

	ArrayHeader *src_header = _array_header(src);
	ArrayHeader *dst_header = _array_header(dst);
	u64 copy_count = src_header->count < dst_header->capacity ? src_header->count : dst_header->capacity;
	memcpy((void *)dst, (void *)src, copy_count * src_header->item_size);
	dst_header->count = copy_count;
}

GenericArray _array_append_alloc(const Allocator *allocator, GenericArray array, void *value, u64 item_size) {
	wapp_runtime_assert(allocator != NULL && array != NULL, "`allocator` and `array` should not be NULL");
	_array_validate(array, item_size);

	GenericArray output = array;

	ArrayHeader *header = _array_header(array);
	if (header->count >= header->capacity) {
		u64 new_capacity = wapp_misc_utils_u64_round_up_pow2(header->capacity * 2);
		output           = (GenericArray )_array_alloc_capacity(allocator, new_capacity, header->item_size, false);
		if (!output) {
			output = array;
			goto RETURN_ARRAY_APPEND_ALLOC;
		}
		_array_copy_capped(output, array, item_size);
	}

	_array_append_capped(output, value, item_size);

RETURN_ARRAY_APPEND_ALLOC:
	return output;
}

GenericArray _array_extend_alloc(const Allocator *allocator, GenericArray dst, const GenericArray src, u64 item_size) {
	wapp_runtime_assert(allocator != NULL && dst != NULL && src != NULL, "`allocator`, `dst` and `src` should not be NULL");
	_array_validate(dst, item_size);
	_array_validate(src, item_size);

	GenericArray output = dst;

	ArrayHeader *src_header = _array_header(src);
	ArrayHeader *dst_header = _array_header(dst);
	u64 remaining_capacity = dst_header->capacity - dst_header->count;
	if (src_header->count >= remaining_capacity) {
		u64 new_capacity  = wapp_misc_utils_u64_round_up_pow2(dst_header->capacity * 2);
		output            = (GenericArray )_array_alloc_capacity(allocator, new_capacity, dst_header->item_size, false);
		if (!output) {
			output = dst;
			goto RETURN_ARRAY_EXTEND_ALLOC;
		}
		_array_copy_capped(output, dst, item_size);
	}

	_array_extend_capped(output, src, item_size);

RETURN_ARRAY_EXTEND_ALLOC:
	return output;
}

GenericArray _array_copy_alloc(const Allocator *allocator, GenericArray dst, const GenericArray src, u64 item_size) {
	wapp_runtime_assert(allocator != NULL && dst != NULL && src != NULL, "`allocator`, `dst` and `src` should not be NULL");
	_array_validate(dst, item_size);
	_array_validate(src, item_size);

	GenericArray output = dst;

	ArrayHeader *src_header = _array_header(src);
	ArrayHeader *dst_header = _array_header(dst);
	if (src_header->count >= dst_header->capacity) {
		u64 new_capacity  = wapp_misc_utils_u64_round_up_pow2(dst_header->capacity * 2);
		output            = (GenericArray )_array_alloc_capacity(allocator, new_capacity,
		                                                         src_header->item_size, false);
		if (!output) {
			output = dst;
			goto RETURN_ARRAY_COPY_ALLOC;
		}
	}

	_array_copy_capped(output, src, item_size);

RETURN_ARRAY_COPY_ALLOC:
	return output;
}

void *_array_pop(GenericArray array, u64 item_size) {
	wapp_runtime_assert(array != NULL, "`array` should not be NULL");
	_array_validate(array, item_size);

	ArrayHeader *header = _array_header(array);
	if (header->count == 0) { return NULL; }

	u64 index = header->count - 1;
	void *out = _array_get(array, index, item_size);
	--(header->count);
	return out;
}

void _array_clear(GenericArray array, u64 item_size) {
	wapp_runtime_assert(array != NULL, "`array` should not be NULL");
	_array_validate(array, item_size);

	ArrayHeader *header = _array_header(array);
	header->count = 0;
}

GenericArray _array_alloc_capacity(const Allocator *allocator, u64 capacity, u64 item_size, b8 fill) {
	wapp_runtime_assert(allocator != NULL, "`allocator` should not be NULL");

	GenericArray output = NULL;

	u64 allocation_size = sizeof(ArrayHeader) + item_size * capacity;
	ArrayHeader *header = wapp_mem_allocator_alloc(allocator, allocation_size);
	if (!header) {
		goto RETURN_ARRAY_ALLOC;
	}

	output            = (u8 *)(header + 1);
	header->magic     = WAPP_ARRAY_MAGIC;
	header->count     = fill ? capacity : 0;
	header->capacity  = capacity;
	header->item_size = item_size;

RETURN_ARRAY_ALLOC:
	return output;
}

wapp_persist inline void _array_validate(const GenericArray array, u64 item_size) {
	ArrayHeader *header = _array_header(array);
	wapp_runtime_assert(WAPP_ARRAY_MAGIC == header->magic, "`array` is not a valid wapp array");
	wapp_runtime_assert(item_size == header->item_size, "Invalid item type provided");
}