/*
 *  This file is part of corelibs. (https://git.redxen.eu/corelibs)
 *  Copyright (c) 2021 Alex-David Denes
 *
 *  corelibs is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  corelibs is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with corelibs.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "dynarray.h"

#include <stdbool.h> // bool
#include <stdlib.h>  // malloc() free()
#include <string.h>  // memcpy()

// Exporter
static cl_dynarray_err corelibs_dynarray_export_slice(const cl_dynarray_t*, uintmax_t, uintmax_t, void*);

// Lifetime
static cl_dynarray_err corelibs_dynarray_make_new(size_t, cl_dynarray_t**);
static cl_dynarray_err corelibs_dynarray_make_slice(const cl_dynarray_t*, uintmax_t, uintmax_t, cl_dynarray_t**);
static cl_dynarray_err corelibs_dynarray_free(cl_dynarray_t*);

// Array storage
static cl_dynarray_err corelibs_dynarray_mod_arr_cap(cl_dynarray_t*, uintmax_t);
static cl_dynarray_err corelibs_dynarray_mod_arr_lock(cl_dynarray_t*, bool);

// Array contents
static cl_dynarray_err corelibs_dynarray_mod_ct_app(cl_dynarray_t*, uintmax_t, const void*);
static cl_dynarray_err corelibs_dynarray_mod_ct_ins(cl_dynarray_t*, uintmax_t, uintmax_t, const void*);
static cl_dynarray_err corelibs_dynarray_mod_ct_rep(cl_dynarray_t*, uintmax_t, uintmax_t, const void*);
static cl_dynarray_err corelibs_dynarray_mod_ct_rm(cl_dynarray_t*, uintmax_t, uintmax_t);

// Get array properties
static cl_dynarray_err corelibs_dynarray_get_len(const cl_dynarray_t*, uintmax_t*);
static cl_dynarray_err corelibs_dynarray_get_size(const cl_dynarray_t*, size_t*);
static cl_dynarray_err corelibs_dynarray_get_cap_len(const cl_dynarray_t*, uintmax_t*);
static cl_dynarray_err corelibs_dynarray_get_cap_lock(const cl_dynarray_t*, bool*);

// Compare arrays
static cl_dynarray_err corelibs_dynarray_cmp_data(const cl_dynarray_t* a, const cl_dynarray_t* b, bool* eq);

// Private functions
static cl_dynarray_err corelibs_dynarray_bcheck(const cl_dynarray_t*, uintmax_t, uintmax_t);

struct cl_dynarray_t {
	void*     addr; // Location of element
	uintmax_t len;  // Element count
	struct {
		bool      lock; // Is the capacity frozen?
		uintmax_t len;  // Capacity
	} cap;
	size_t es; // Size of element
};

enum { // Avoid collision in error numbers
	CORELIBS_DYNARRAY_ERR_VAR_NCOMPAT = -7,
	CORELIBS_DYNARRAY_ERR_VAR_INVAL,
	CORELIBS_DYNARRAY_ERR_VAR_IMMUT,
	CORELIBS_DYNARRAY_ERR_VAR_UNDEF,
	CORELIBS_DYNARRAY_ERR_MEM_OOB,
	CORELIBS_DYNARRAY_ERR_MEM_NULL,
	CORELIBS_DYNARRAY_ERR_MEM_ALLOC,
	CORELIBS_DYNARRAY_ERR_UNKOWN = 0,
	CORELIBS_DYNARRAY_ERR_OK     = 1,
};

// Present a unified structure that may receive changes, deprecations and renames without hassle for external users
const struct corelibs_dynarray_interface cl_dynarray = {
	.make = {
		.new   = corelibs_dynarray_make_new,
		.slice = corelibs_dynarray_make_slice,
	},
	.free = corelibs_dynarray_free,
	.mod = {
		.arr = {
			.cap  = corelibs_dynarray_mod_arr_cap,
			.lock = corelibs_dynarray_mod_arr_lock,
		},
		.ct = {
			.app = corelibs_dynarray_mod_ct_app,
			.ins = corelibs_dynarray_mod_ct_ins,
			.rep = corelibs_dynarray_mod_ct_rep,
			.rm  = corelibs_dynarray_mod_ct_rm,
		},
	},
	.cmp = {
		.data = corelibs_dynarray_cmp_data,
	},
	.export = {
		.slice = corelibs_dynarray_export_slice,
	},
	.get = {
		.len  = corelibs_dynarray_get_len,
		.size = corelibs_dynarray_get_size,
		.cap  = {
			.len = corelibs_dynarray_get_cap_len,
			.lock = corelibs_dynarray_get_cap_lock,
		},
	},
	.err = {
		.ok      = CORELIBS_DYNARRAY_ERR_OK,
		.unknown = CORELIBS_DYNARRAY_ERR_UNKOWN,
		.mem = {
			.alloc = CORELIBS_DYNARRAY_ERR_MEM_ALLOC,
			.null  = CORELIBS_DYNARRAY_ERR_MEM_NULL,
			.oob   = CORELIBS_DYNARRAY_ERR_MEM_OOB,
		},
		.var = {
			.undef = CORELIBS_DYNARRAY_ERR_VAR_UNDEF,
			.immut = CORELIBS_DYNARRAY_ERR_VAR_IMMUT,
			.inval = CORELIBS_DYNARRAY_ERR_VAR_INVAL,
			.ncompat = CORELIBS_DYNARRAY_ERR_VAR_NCOMPAT,
		},
	},
};

static cl_dynarray_err
corelibs_dynarray_make_new(size_t sbyte, cl_dynarray_t** ptr)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (ptr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	cl_dynarray_t* new = malloc(sizeof(*new));
	if (new == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
		goto ret;
	}

	new->addr     = NULL;
	new->es       = sbyte;
	new->len      = 0;
	new->cap.len  = 0;
	new->cap.lock = false;

	*ptr = new;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_make_slice(const cl_dynarray_t* arr, uintmax_t pos, uintmax_t cnt, cl_dynarray_t** save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (save == NULL || arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if (cnt == 0) {
		// Don't copy anything, just make new array
		err = corelibs_dynarray_make_new(arr->es, save);
		goto ret; // Return even if no error is met, nothing more to do
	}

	// Can we slice these elements?
	if ((err = corelibs_dynarray_bcheck(arr, pos, cnt)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	cl_dynarray_t* new;
	// Create new array
	if ((err = corelibs_dynarray_make_new(arr->es, &new)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	// Resize array to fit contents
	if ((err = corelibs_dynarray_mod_arr_cap(new, cnt)) != CORELIBS_DYNARRAY_ERR_OK) {
		corelibs_dynarray_free(new);
		goto ret;
	}

	// Copy contents from old array to new one
	if ((err = corelibs_dynarray_export_slice(arr, pos, cnt, new->addr)) != CORELIBS_DYNARRAY_ERR_OK) {
		corelibs_dynarray_free(new);
		goto ret;
	}
	new->len      = cnt;
	new->cap.lock = arr->cap.lock; // Inherit capacity lock

	*save = new;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_free(cl_dynarray_t* arr)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if ((err = corelibs_dynarray_mod_arr_cap(arr, 0)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	free(arr);
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_mod_arr_cap(cl_dynarray_t* arr, uintmax_t len)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if (len == 0) {
		free(arr->addr);
		arr->cap.len = 0;
		goto ret; // Return success (default)
	}

	if (arr->cap.lock) {
		err = CORELIBS_DYNARRAY_ERR_VAR_IMMUT;
		goto ret;
	}

	void*        reg = NULL;
	const size_t nl  = len * arr->es;

	if (arr->addr == NULL) {
		if ((reg = malloc(nl)) == NULL) {
			err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
			goto ret;
		}
	} else if (arr->cap.len != len) {
		if ((reg = realloc(arr->addr, nl)) == NULL) {
			err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
			goto ret;
		}
	}

	arr->cap.len = len;
	arr->addr    = reg;
	if (arr->cap.len < arr->len) arr->len = arr->cap.len; // Cut out discarded elements if resized to shorter size
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_mod_arr_lock(cl_dynarray_t* arr, bool lock)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	arr->cap.lock = lock;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_mod_ct_app(cl_dynarray_t* arr, uintmax_t cnt, const void* elem)
{
	return corelibs_dynarray_mod_ct_ins(arr, arr->len, cnt, elem);
}

static cl_dynarray_err
corelibs_dynarray_mod_ct_ins(cl_dynarray_t* arr, uintmax_t pos, uintmax_t cnt, const void* elem)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || elem == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	// Resize array to fit inserted objects
	if ((err = corelibs_dynarray_mod_arr_cap(arr, ((arr->cap.len < pos) ? pos : arr->cap.len) + cnt)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	// CHECKPOINT: From here it is safe to commit changes as required conditions are met
	//             and no errors should be possible (unless you have some special hardware)

	uintmax_t clen = arr->len; // Lenght pre-resize

	if (arr->len < pos) arr->len = pos;
	arr->len += cnt;

	uintptr_t src, // Source of copy address without pointer aritmethic
	    dest;      // Destination to copy to
	size_t bcnt;   // Amount of bytes to copy

	// If we are inserting and not appending
	if (pos < clen) {
		src  = (uintptr_t) arr->addr + (pos * arr->es);
		dest = src + (cnt * arr->es);
		bcnt = (clen - pos) * arr->es;
		memmove((void*) dest, (void*) src, bcnt); // Shift bytes to after insertion region
	}

	src  = (uintptr_t) elem;
	dest = (uintptr_t) arr->addr + (pos * arr->es);
	bcnt = cnt * arr->es;
	memcpy((void*) dest, (void*) src, bcnt); // No overlaps possible
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_mod_ct_rep(cl_dynarray_t* arr, uintmax_t pos, uintmax_t cnt, const void* elem)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || elem == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if (corelibs_dynarray_bcheck(arr, pos, cnt) == CORELIBS_DYNARRAY_ERR_MEM_OOB) {
		// Resize array to fit new elements
		if ((err = corelibs_dynarray_mod_arr_cap(arr, pos + cnt)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;
	}

	// CHECKPOINT: From here it is safe to commit changes as required conditions are met
	//             and no errors should be possible (unless you have some special hardware)

	uintptr_t src, // Source of copy address without pointer aritmethic
	    dest;      // Destination to copy to
	size_t bcnt;   // Amount of bytes to copy

	src  = (uintptr_t) elem;
	dest = (uintptr_t) arr->addr + (pos * arr->es);
	bcnt = cnt * arr->es;
	memcpy((void*) dest, (void*) src, bcnt);
	if (arr->len < pos + cnt) arr->len = pos + cnt; // Set length at end of replacement if not already same or longer
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_mod_ct_rm(cl_dynarray_t* arr, uintmax_t pos, uintmax_t cnt)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	// Are we removing elements we don't have?
	if ((err = corelibs_dynarray_bcheck(arr, pos, cnt)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	// Allocate intermediate buffer
	void* tbuf = malloc(arr->es * arr->len);
	if (tbuf == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
		goto ret;
	}

	// CHECKPOINT: From here it is safe to commit changes as required conditions are met
	//             and no errors should be possible (unless you have some special hardware)

	arr->len -= cnt; // We remove cnt elements from array

	uintptr_t src, // Source of copy address without pointer aritmethic
	    dest;      // Destination to copy to
	size_t bcnt;   // Amount of bytes to copy

	dest = (uintptr_t) tbuf;
	src  = (uintptr_t) arr->addr;
	bcnt = arr->len * arr->es;
	memcpy((void*) dest, (void*) src, bcnt); // Copy current contents up to arr->len to intermediate buffer

	// If tail is the only thing removed, don't copy back
	if (pos + cnt != arr->len) {
		// Copy back slice and overwrite region removed
		dest += pos * arr->es;
		src += (pos + cnt) * arr->es;
		bcnt -= pos * arr->es;
		memcpy((void*) dest, (void*) src, bcnt);
	}

	free(arr->addr);
	arr->addr = tbuf; // Swap buffers and free previous one
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_export_slice(const cl_dynarray_t* arr, uintmax_t pos, uintmax_t cnt, void* save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || save == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}
	if (cnt == 0) goto ret;

	// Do we have the requested slice?
	if ((err = corelibs_dynarray_bcheck(arr, pos, cnt)) != CORELIBS_DYNARRAY_ERR_OK) goto ret;

	uintptr_t src, // Source of copy address without pointer aritmethic
	    dest;      // Destination to copy to
	size_t bcnt;   // Amount of bytes to copy

	src  = (uintptr_t) arr->addr + (arr->es * pos);
	dest = (uintptr_t) save;
	bcnt = arr->es * cnt;
	memcpy((void*) dest, (void*) src, bcnt);
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_get_len(const cl_dynarray_t* arr, uintmax_t* save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || save == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	*save = arr->len;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_get_cap_len(const cl_dynarray_t* arr, uintmax_t* save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || save == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	*save = arr->cap.len;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_get_cap_lock(const cl_dynarray_t* arr, bool* save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || save == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	*save = arr->cap.lock;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_get_size(const cl_dynarray_t* arr, size_t* save)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL || save == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	*save = arr->es;
ret:
	return err;
}

static cl_dynarray_err
corelibs_dynarray_cmp_data(const cl_dynarray_t* a, const cl_dynarray_t* b, bool* eq)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (a == NULL || b == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if (a->es != b->es) {
		err = CORELIBS_DYNARRAY_ERR_VAR_NCOMPAT;
		goto ret;
	}

	if (a->len != b->len) {
		*eq = false;
		goto ret;
	}

	*eq = (memcmp(a->addr, b->addr, a->len) != 0) ? false : true;
ret:
	return err;
}

// Private functions
static cl_dynarray_err
corelibs_dynarray_bcheck(const cl_dynarray_t* arr, uintmax_t pos, uintmax_t len)
{
	cl_dynarray_err err = CORELIBS_DYNARRAY_ERR_OK;

	if (arr == NULL) {
		err = CORELIBS_DYNARRAY_ERR_MEM_NULL;
		goto ret;
	}

	if (arr->cap.len < pos + len) {
		err = CORELIBS_DYNARRAY_ERR_MEM_OOB;
		goto ret;
	}
ret:
	return err;
}