/*
 * Holds procs to help with list operations
 * Contains groups:
 *			Misc
 *			Sorting
 */

/*
 * Misc
 */

#define LAZYINITLIST(L) if (!L) L = list()
#define UNSETEMPTY(L) if (L && !L.len) L = null
#define LAZYREMOVE(L, I) if(L) { L -= I; if(!L.len) { L = null; } }
#define LAZYADD(L, I) if(!L) { L = list(); } L += I;
#define LAZYACCESS(L, I) (L ? (isnum(I) ? (I > 0 && I <= L.len ? L[I] : null) : L[I]) : null)
#define LAZYSET(L, K, V) if(!L) { L = list(); } L[K] = V;
#define LAZYLEN(L) length(L)
#define LAZYCLEARLIST(L) if(L) L.Cut()
#define SANITIZE_LIST(L) ( islist(L) ? L : list() )

//Returns a list in plain english as a string
/proc/english_list(list/input, nothing_text = "nothing", and_text = " and ", comma_text = ", ", final_comma_text = "" )
	var/total = input.len
	if (!total)
		return "[nothing_text]"
	else if (total == 1)
		return "[input[1]]"
	else if (total == 2)
		return "[input[1]][and_text][input[2]]"
	else
		var/output = ""
		var/index = 1
		while (index < total)
			if (index == total - 1)
				comma_text = final_comma_text

			output += "[input[index]][comma_text]"
			index++

		return "[output][and_text][input[index]]"

//Returns list element or null. Should prevent "index out of bounds" error.
/proc/listgetindex(list/L, index)
	if(LAZYLEN(L))
		if(isnum(index) && ISINTEGER(index))
			if(ISINRANGE(index,1,L.len))
				return L[index]
		else if(index in L)
			return L[index]
	return

//Return either pick(list) or null if list is not of type /list or is empty
/proc/safepick(list/L)
	if(LAZYLEN(L))
		return pick(L)

//Checks if the list is empty
/proc/isemptylist(list/L)
	if(!L.len)
		return TRUE
	return FALSE

//Checks for specific types in a list
/proc/is_type_in_list(atom/A, list/L)
	if(!LAZYLEN(L) || !A)
		return FALSE
	for(var/type in L)
		if(istype(A, type))
			return TRUE
	return FALSE

//Checks for specific types in specifically structured (Assoc "type" = TRUE) lists ('typecaches')
/proc/is_type_in_typecache(atom/A, list/L)
	if(!LAZYLEN(L) || !A)

		return FALSE
	if(ispath(A))
		. = L[A]
	else
		. = L[A.type]

//Checks for a string in a list
/proc/is_string_in_list(string, list/L)
	if(!LAZYLEN(L) || !string)
		return
	for(var/V in L)
		if(string == V)
			return TRUE
	return

//Removes a string from a list
/proc/remove_strings_from_list(string, list/L)
	if(!LAZYLEN(L) || !string)
		return
	for(var/V in L)
		if(V == string)
			L -= V //No return here so that it removes all strings of that type
	return

//returns a new list with only atoms that are in typecache L
/proc/typecache_filter_list(list/atoms, list/typecache)
	. = list()
	for(var/thing in atoms)
		var/atom/A = thing
		if (typecache[A.type])
			. += A

/proc/typecache_filter_list_reverse(list/atoms, list/typecache)
	. = list()
	for(var/thing in atoms)
		var/atom/A = thing
		if(!typecache[A.type])
			. += A

/proc/typecache_filter_multi_list_exclusion(list/atoms, list/typecache_include, list/typecache_exclude)
	. = list()
	for(var/thing in atoms)
		var/atom/A = thing
		if(typecache_include[A.type] && !typecache_exclude[A.type])
			. += A

//Like typesof() or subtypesof(), but returns a typecache instead of a list
/proc/typecacheof(path, ignore_root_path, only_root_path = FALSE)
	if(ispath(path))
		var/list/types = list()
		if(only_root_path)
			types = list(path)
		else
			types = ignore_root_path ? subtypesof(path) : typesof(path)
		var/list/L = list()
		for(var/T in types)
			L[T] = TRUE
		return L
	else if(islist(path))
		var/list/pathlist = path
		var/list/L = list()
		if(ignore_root_path)
			for(var/P in pathlist)
				for(var/T in subtypesof(P))
					L[T] = TRUE
		else
			for(var/P in pathlist)
				if(only_root_path)
					L[P] = TRUE
				else
					for(var/T in typesof(P))
						L[T] = TRUE
		return L

//Empties the list by setting the length to 0. Hopefully the elements get garbage collected
/proc/clearlist(list/list)
	if(istype(list))
		list.len = 0
	return

//Removes any null entries from the list
//Returns TRUE if the list had nulls, FALSE otherwise
/proc/listclearnulls(list/L)
	var/start_len = L.len
	var/list/N = new(start_len)
	L -= N
	return L.len < start_len

/*
 * Returns list containing all the entries from first list that are not present in second.
 * If skiprep = 1, repeated elements are treated as one.
 * If either of arguments is not a list, returns null
 */
/proc/difflist(list/first, list/second, skiprep=0)
	if(!islist(first) || !islist(second))
		return
	var/list/result = new
	if(skiprep)
		for(var/e in first)
			if(!(e in result) && !(e in second))
				result += e
	else
		result = first - second
	return result

/*
 * Returns list containing entries that are in either list but not both.
 * If skipref = 1, repeated elements are treated as one.
 * If either of arguments is not a list, returns null
 */
/proc/uniquemergelist(list/first, list/second, skiprep=0)
	if(!islist(first) || !islist(second))
		return
	var/list/result = new
	if(skiprep)
		result = difflist(first, second, skiprep)+difflist(second, first, skiprep)
	else
		result = first ^ second
	return result

//Picks a random element from a list based on a weighting system:
//1. Adds up the total of weights for each element
//2. Gets a number between 1 and that total
//3. For each element in the list, subtracts its weighting from that number
//4. If that makes the number 0 or less, return that element.
/proc/pickweight(list/L)
	var/total = 0
	var/item
	for (item in L)
		if (!L[item])
			L[item] = 1
		total += L[item]

	total = rand(1, total)
	for (item in L)
		total -=L [item]
		if (total <= 0)
			return item

	return null

/proc/pickweightAllowZero(list/L) //The original pickweight proc will sometimes pick entries with zero weight.  I'm not sure if changing the original will break anything, so I left it be.
	var/total = 0
	var/item
	for (item in L)
		if (!L[item])
			L[item] = 0
		total += L[item]

	total = rand(0, total)
	for (item in L)
		total -=L [item]
		if (total <= 0 && L[item])
			return item

	return null

//Pick a random element from the list and remove it from the list.
/proc/pick_n_take(list/L)
	if(L.len)
		var/picked = rand(1,L.len)
		. = L[picked]
		L.Cut(picked,picked+1)			//Cut is far more efficient that Remove()

//Returns the top(last) element from the list and removes it from the list (typical stack function)
/proc/pop(list/L)
	if(L.len)
		. = L[L.len]
		L.len--

/proc/popleft(list/L)
	if(L.len)
		. = L[1]
		L.Cut(1,2)

/proc/sorted_insert(list/L, thing, comparator)
	var/pos = L.len
	while(pos > 0 && call(comparator)(thing, L[pos]) > 0)
		pos--
	L.Insert(pos+1, thing)

// Returns the next item in a list
/proc/next_list_item(item, list/L)
	var/i
	i = L.Find(item)
	if(i == L.len)
		i = 1
	else
		i++
	return L[i]

// Returns the previous item in a list
/proc/previous_list_item(item, list/L)
	var/i
	i = L.Find(item)
	if(i == 1)
		i = L.len
	else
		i--
	return L[i]

//Randomize: Return the list in a random order
/proc/shuffle(list/L)
	if(!L)
		return
	L = L.Copy()

	for(var/i=1, i<L.len, ++i)
		L.Swap(i,rand(i,L.len))

	return L

//same, but returns nothing and acts on list in place
/proc/shuffle_inplace(list/L)
	if(!L)
		return

	for(var/i=1, i<L.len, ++i)
		L.Swap(i,rand(i,L.len))

//Return a list with no duplicate entries
/proc/uniqueList(list/L)
	. = list()
	for(var/i in L)
		. |= i

//same, but returns nothing and acts on list in place (also handles associated values properly)
/proc/uniqueList_inplace(list/L)
	var/temp = L.Copy()
	L.len = 0
	for(var/key in temp)
		if (isnum(key))
			L |= key
		else
			L[key] = temp[key]

//for sorting clients or mobs by ckey
/proc/sortKey(list/L, order=1)
	return sortTim(L, order >= 0 ? /proc/cmp_ckey_asc : /proc/cmp_ckey_dsc)

//Specifically for record datums in a list.
/proc/sortRecord(list/L, field = "name", order = 1)
	GLOB.cmp_field = field
	return sortTim(L, order >= 0 ? /proc/cmp_records_asc : /proc/cmp_records_dsc)

//any value in a list
/proc/sortList(list/L, cmp=/proc/cmp_text_asc)
	return sortTim(L.Copy(), cmp)

//uses sortList() but uses the var's name specifically. This should probably be using mergeAtom() instead
/proc/sortNames(list/L, order=1)
	return sortTim(L, order >= 0 ? /proc/cmp_name_asc : /proc/cmp_name_dsc)


//Converts a bitfield to a list of numbers (or words if a wordlist is provided)
/proc/bitfield2list(bitfield = 0, list/wordlist)
	var/list/r = list()
	if(islist(wordlist))
		var/max = min(wordlist.len,16)
		var/bit = 1
		for(var/i=1, i<=max, i++)
			if(bitfield & bit)
				r += wordlist[i]
			bit = bit << 1
	else
		for(var/bit=1, bit<=65535, bit = bit << 1)
			if(bitfield & bit)
				r += bit

	return r

// Returns the key based on the index
#define KEYBYINDEX(L, index) (((index <= length(L)) && (index > 0)) ? L[index] : null)

/proc/count_by_type(list/L, type)
	var/i = 0
	for(var/T in L)
		if(istype(T, type))
			i++
	return i

/proc/find_record(field, value, list/L)
	for(var/datum/data/record/R in L)
		if(R.fields[field] == value)
			return R


//Move a single element from position fromIndex within a list, to position toIndex
//All elements in the range [1,toIndex) before the move will be before the pivot afterwards
//All elements in the range [toIndex, L.len+1) before the move will be after the pivot afterwards
//In other words, it's as if the range [fromIndex,toIndex) have been rotated using a <<< operation common to other languages.
//fromIndex and toIndex must be in the range [1,L.len+1]
//This will preserve associations ~Carnie
/proc/moveElement(list/L, fromIndex, toIndex)
	if(fromIndex == toIndex || fromIndex+1 == toIndex)	//no need to move
		return
	if(fromIndex > toIndex)
		++fromIndex	//since a null will be inserted before fromIndex, the index needs to be nudged right by one

	L.Insert(toIndex, null)
	L.Swap(fromIndex, toIndex)
	L.Cut(fromIndex, fromIndex+1)


//Move elements [fromIndex,fromIndex+len) to [toIndex-len, toIndex)
//Same as moveElement but for ranges of elements
//This will preserve associations ~Carnie
/proc/moveRange(list/L, fromIndex, toIndex, len=1)
	var/distance = abs(toIndex - fromIndex)
	if(len >= distance)	//there are more elements to be moved than the distance to be moved. Therefore the same result can be achieved (with fewer operations) by moving elements between where we are and where we are going. The result being, our range we are moving is shifted left or right by dist elements
		if(fromIndex <= toIndex)
			return	//no need to move
		fromIndex += len	//we want to shift left instead of right

		for(var/i=0, i<distance, ++i)
			L.Insert(fromIndex, null)
			L.Swap(fromIndex, toIndex)
			L.Cut(toIndex, toIndex+1)
	else
		if(fromIndex > toIndex)
			fromIndex += len

		for(var/i=0, i<len, ++i)
			L.Insert(toIndex, null)
			L.Swap(fromIndex, toIndex)
			L.Cut(fromIndex, fromIndex+1)

//Move elements from [fromIndex, fromIndex+len) to [toIndex, toIndex+len)
//Move any elements being overwritten by the move to the now-empty elements, preserving order
//Note: if the two ranges overlap, only the destination order will be preserved fully, since some elements will be within both ranges ~Carnie
/proc/swapRange(list/L, fromIndex, toIndex, len=1)
	var/distance = abs(toIndex - fromIndex)
	if(len > distance)	//there is an overlap, therefore swapping each element will require more swaps than inserting new elements
		if(fromIndex < toIndex)
			toIndex += len
		else
			fromIndex += len

		for(var/i=0, i<distance, ++i)
			L.Insert(fromIndex, null)
			L.Swap(fromIndex, toIndex)
			L.Cut(toIndex, toIndex+1)
	else
		if(toIndex > fromIndex)
			var/a = toIndex
			toIndex = fromIndex
			fromIndex = a

		for(var/i=0, i<len, ++i)
			L.Swap(fromIndex++, toIndex++)

//replaces reverseList ~Carnie
/proc/reverseRange(list/L, start=1, end=0)
	if(L.len)
		start = start % L.len
		end = end % (L.len+1)
		if(start <= 0)
			start += L.len
		if(end <= 0)
			end += L.len + 1

		--end
		while(start < end)
			L.Swap(start++,end--)

	return L


//return first thing in L which has var/varname == value
//this is typecaste as list/L, but you could actually feed it an atom instead.
//completely safe to use
/proc/getElementByVar(list/L, varname, value)
	varname = "[varname]"
	for(var/datum/D in L)
		if(D.vars.Find(varname))
			if(D.vars[varname] == value)
				return D

//remove all nulls from a list
/proc/removeNullsFromList(list/L)
	while(L.Remove(null))
		continue
	return L

//Copies a list, and all lists inside it recusively
//Does not copy any other reference type
/proc/deepCopyList(list/l)
	if(!islist(l))
		return l
	. = l.Copy()
	for(var/i = 1 to l.len)
		if(islist(.[i]))
			.[i] = .(.[i])

//takes an input_key, as text, and the list of keys already used, outputting a replacement key in the format of "[input_key] ([number_of_duplicates])" if it finds a duplicate
//use this for lists of things that might have the same name, like mobs or objects, that you plan on giving to a player as input
/proc/avoid_assoc_duplicate_keys(input_key, list/used_key_list)
	if(!input_key || !istype(used_key_list))
		return
	if(used_key_list[input_key])
		used_key_list[input_key]++
		input_key = "[input_key] ([used_key_list[input_key]])"
	else
		used_key_list[input_key] = 1
	return input_key

#if DM_VERSION > 512
#error Remie said that lummox was adding a way to get a lists
#error contents via list.values, if that is true remove this
#error otherwise, update the version and bug lummox
#endif
//Flattens a keyed list into a list of it's contents
/proc/flatten_list(list/key_list)
	if(!islist(key_list))
		return null
	. = list()
	for(var/key in key_list)
		. |= key_list[key]

//Picks from the list, with some safeties, and returns the "default" arg if it fails
#define DEFAULTPICK(L, default) ((islist(L) && length(L)) ? pick(L) : default)

/* Definining a counter as a series of key -> numeric value entries

 * All these procs modify in place.
*/

/proc/counterlist_scale(list/L, scalar)
	var/list/out = list()
	for(var/key in L)
		out[key] = L[key] * scalar
	. = out

/proc/counterlist_sum(list/L)
	. = 0
	for(var/key in L)
		. += L[key]

/proc/counterlist_normalise(list/L)
	var/avg = counterlist_sum(L)
	if(avg != 0)
		. = counterlist_scale(L, 1 / avg)
	else
		. = L

/proc/counterlist_combine(list/L1, list/L2)
	for(var/key in L2)
		var/other_value = L2[key]
		if(key in L1)
			L1[key] += other_value
		else
			L1[key] = other_value