/*
 *  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_OK = 0,
	CORELIBS_DYNARRAY_ERR_UNKOWN,
	CORELIBS_DYNARRAY_ERR_MEM_OOB,
	CORELIBS_DYNARRAY_ERR_MEM_NULL,
	CORELIBS_DYNARRAY_ERR_MEM_ALLOC,
	CORELIBS_DYNARRAY_ERR_VAR_NCOMPAT,
	CORELIBS_DYNARRAY_ERR_VAR_INVAL,
	CORELIBS_DYNARRAY_ERR_VAR_IMMUT,
	CORELIBS_DYNARRAY_ERR_VAR_UNDEF,
};

// 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;
	if (!err) {
		cl_dynarray_t *new = malloc (sizeof (*new));
		if (new != NULL) {
			new->addr     = NULL;
			new->es       = sbyte;
			new->len      = 0;
			new->cap.len  = 0;
			new->cap.lock = false;
			*ptr          = new;
		} else {
			err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
		}
	}
	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;
	if (!err) {
		if (cnt == 0) {
			// Don't copy anything, just make new array
			return corelibs_dynarray_make_new (arr->es, save);
		}

		// Can we slice these elements?
		if (!(err = corelibs_dynarray_bcheck (arr, pos, cnt))) {
			// Create new array
			cl_dynarray_t *new;
			if (!(err = corelibs_dynarray_make_new (arr->es, &new))) {
				// Resize array to fit contents
				if (!(err = corelibs_dynarray_mod_arr_cap (new, cnt))) {
					// Copy contents from old array to new one
					if (!(err = corelibs_dynarray_export_slice (arr, pos, cnt, new->addr))) {
						new->len      = cnt;
						new->cap.lock = arr->cap.lock; // Inherit capacity lock
						*save         = new;
					}
				}
				if (err) corelibs_dynarray_free (new);
			}
		}
	}
	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;
	if (!err) {
		if (!(err = corelibs_dynarray_mod_arr_cap (arr, 0))) {
			free (arr);
		}
	}
	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;
	if (!err) {
		if (len == 0) {
			free (arr->addr);
			arr->cap.len = 0;
		} else if (!arr->cap.lock) {
			void *       reg = NULL;
			const size_t nl  = len * arr->es;

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

			if (reg != NULL) {
				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
			} else {
				err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
			}
		} else {
			err = CORELIBS_DYNARRAY_ERR_VAR_IMMUT;
		}
	}
	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;
	if (!err) {
		arr->cap.lock = lock;
	}
	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;
	if (!err) {
		// Resize array to fit inserted objects
		if (!(err = corelibs_dynarray_mod_arr_cap (arr, ((arr->cap.len < pos) ? pos : arr->cap.len) + cnt))) {
			// 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
		}
	}
	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;
	if (!err) {
		if (corelibs_dynarray_bcheck (arr, pos, cnt) == CORELIBS_DYNARRAY_ERR_MEM_OOB) {
			// Resize array to fit new elements
			err = corelibs_dynarray_mod_arr_cap (arr, pos + cnt);
		}

		if (!err) {
			// 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
		}
	}
	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;
	if (!err) {
		// Are we removing elements we don't have?
		if (!(err = corelibs_dynarray_bcheck (arr, pos, cnt))) {
			// Allocate intermediate buffer
			void *tbuf = malloc (arr->es * arr->len);
			if (tbuf != NULL) {
				// 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
			} else {
				err = CORELIBS_DYNARRAY_ERR_MEM_ALLOC;
			}
		}
	}
	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;
	if (!err || cnt != 0) {
		// Do we have the requested slice?
		if (!(err = corelibs_dynarray_bcheck (arr, pos, cnt))) {
			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);
		}
	}
	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;
	if (!err) {
		*save = arr->len;
	}
	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;
	if (!err) {
		*save = arr->cap.len;
	}
	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;
	if (!err) {
		*save = arr->cap.lock;
	}
	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;
	if (!err) {
		*save = arr->es;
	}
	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;
	if (a->es != b->es) err = CORELIBS_DYNARRAY_ERR_VAR_NCOMPAT;
	if (!err) {
		if (a->len != b->len) {
			*eq = false;
		} else {
			*eq = (memcmp (a->addr, b->addr, a->len) != 0) ? false : true;
		}
	}
	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;
	if (arr->cap.len < pos + len) err = CORELIBS_DYNARRAY_ERR_MEM_OOB;
	return err;
}