// 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 _array_header(ARRAY) (ArrayHeader *)(wapp_pointer_offset(ARRAY, (i64)sizeof(ArrayHeader) * -1))

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 wapp_pointer_offset(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  = wapp_pointer_offset(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,
                                 ArrayInitFlags flags, 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, flags,
		                                                        header->item_size);
		if (!output) {
			output = array;
			goto RETURN_ARRAY_APPEND_ALLOC;
		}
		_array_copy_capped(output, array, item_size);
	}

	_array_append_capped(output, value, item_size);

	if ((flags & ARRAY_INIT_FILLED) == ARRAY_INIT_FILLED) {
		_array_set_count(output, _array_capacity(output));
	}

RETURN_ARRAY_APPEND_ALLOC:
	return output;
}

GenericArray _array_extend_alloc(const Allocator *allocator, GenericArray dst, const GenericArray src,
                                 ArrayInitFlags flags, 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,
		                                                         flags, dst_header->item_size);
		if (!output) {
			output = dst;
			goto RETURN_ARRAY_EXTEND_ALLOC;
		}
		_array_copy_capped(output, dst, item_size);
	}

	_array_extend_capped(output, src, item_size);

	if ((flags & ARRAY_INIT_FILLED) == ARRAY_INIT_FILLED) {
		_array_set_count(output, _array_capacity(output));
	}

RETURN_ARRAY_EXTEND_ALLOC:
	return output;
}

GenericArray _array_copy_alloc(const Allocator *allocator, GenericArray dst, const GenericArray src,
                               ArrayInitFlags flags, 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,
		                                                         flags, src_header->item_size);
		if (!output) {
			output = dst;
			goto RETURN_ARRAY_COPY_ALLOC;
		}
	}

	_array_copy_capped(output, src, item_size);

	if ((flags & ARRAY_INIT_FILLED) == ARRAY_INIT_FILLED) {
		_array_set_count(output, _array_capacity(output));
	}

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;
}

u64 _array_calc_alloc_size(u64 capacity, u64 item_size) {
	return sizeof(ArrayHeader) + item_size * capacity;
}

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

	GenericArray output = NULL;

	u64 allocation_size = _array_calc_alloc_size(capacity, item_size);
	void *buffer        = wapp_mem_allocator_alloc(allocator, allocation_size);
	if (!buffer) {
		goto RETURN_ARRAY_ALLOC;
	}

	output = _array_from_preallocated_buffer(buffer, allocation_size, flags, item_size);

RETURN_ARRAY_ALLOC:
	return output;
}


GenericArray _array_from_preallocated_buffer(void *buffer, u64 buffer_size, ArrayInitFlags flags,
                                             u64 item_size) {
	wapp_runtime_assert(buffer != NULL, "`buffer` should not be NULL");

	i64 data_buffer_size = (i64)buffer_size - (i64)(sizeof(ArrayHeader));
	if (data_buffer_size <= 0) {
		return NULL;
	}

	u64 item_capacity   = (u64)data_buffer_size / item_size;
	ArrayHeader *header = (ArrayHeader *)buffer;
	GenericArray output = (u8 *)(header + 1);
	header->magic       = WAPP_ARRAY_MAGIC;
	header->count       = flags & ARRAY_INIT_FILLED ? item_capacity : 0;
	header->capacity    = item_capacity;
	header->item_size   = item_size;

	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");
}