Deleting characters (#83989)

## About The Pull Request

Adds a button to delete characters, and when deleted it flips to the
nearest character, wow(the last character can't be deleted(I guess)).

### Video: 

https://github.com/tgstation/tgstation/assets/78199449/3ad1157a-6c1c-4fb2-9b0d-1da791cad989

## Why It's Good For The Game

Once you know how to create characters, you sometimes want to be able to
delete them.
The reasons for this can be... as simple as freeing up a slot, or
deleting them in order to remake them.
I think this is quite a useful feature that should have been there
before.

## Changelog

🆑 Vishenka0704
qol: Ability to delete characters(yourself)
/🆑

code/modules/client/preferences.dm

@@ -223,6 +223,25 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 
 			character_preview_view.update_body()
 
+			return TRUE
+		if ("remove_slot")
+			var/picked_slot = params["slot"]
+			var/confidence_check = tgui_input_text(usr, "To confirm the deletion of a character, type the name of the character.", "Character Deletion")
+			if(confidence_check != params["name"])
+				return FALSE
+
+			if(!remove_character(picked_slot))
+				return FALSE
+
+			if (!load_character(params["slotToJump"]))
+				randomise_appearance_prefs()
+				save_character()
+
+			for (var/datum/preference_middleware/preference_middleware as anything in middleware)
+				preference_middleware.on_new_character(usr)
+
+			tainted_character_profiles = TRUE
+			character_preview_view.update_body();
 			return TRUE
 		if ("rotate")
 			character_preview_view.setDir(turn(character_preview_view.dir, -90))

code/modules/client/preferences_savefile.dm

@@ -368,6 +368,16 @@ SAVEFILE UPDATING/VERSIONING - 'Simplified', or rather, more coder-friendly ~Car
 
 	return TRUE
 
+/datum/preferences/proc/remove_character(slot)
+	SHOULD_NOT_SLEEP(TRUE)
+	if(!slot)
+		return FALSE
+	slot = sanitize_integer(slot, 1, max_save_slots, initial(default_slot))
+
+	var/tree_key = "character[slot]"
+	savefile.remove_entry(tree_key)
+	return TRUE
+
 /datum/preferences/proc/sanitize_be_special(list/input_be_special)
 	var/list/output = list()
 

tgui/packages/tgui/interfaces/PreferencesMenu/CharacterPreferenceWindow.tsx

@@ -101,15 +101,44 @@ export const CharacterPreferenceWindow = (props) => {
               profiles={data.character_profiles}
             />
           </Stack.Item>
+          <Stack.Item align="center">
+            <Button
+              color="red"
+              disabled={
+                Object.values(data.character_profiles).filter((val) => val)
+                  .length < 2
+              } // check if existing chars more than one
+              onClick={() => {
+                let choicedSlot = data.active_slot - 1;
+                let availableSlots = Object.keys(data.character_profiles)
+                  .filter((slot) => data.character_profiles[slot] !== null)
+                  .map((slot) => parseInt(slot, 10)); // get all busy slots as num
 
+                availableSlots.splice(availableSlots.indexOf(choicedSlot), 1); // remove our slot(which we want to delete)
+
+                let slotToJump = availableSlots.reduce((prev, curr) => {
+                  return Math.abs(curr - choicedSlot) <
+                    Math.abs(prev - choicedSlot)
+                    ? curr
+                    : prev;
+                }); // get nearest slot
+
+                act('remove_slot', {
+                  slot: data.active_slot,
+                  name: Object.values(data.character_profiles)[choicedSlot],
+                  slotToJump: slotToJump + 1,
+                });
+              }}
+            >
+              Delete Character
+            </Button>
+          </Stack.Item>
           {!data.content_unlocked && (
             <Stack.Item align="center">
               Buy BYOND premium for more slots!
             </Stack.Item>
           )}
-
           <Stack.Divider />
-
           <Stack.Item>
             <Stack fill>
               <Stack.Item grow>
@@ -168,9 +197,7 @@ export const CharacterPreferenceWindow = (props) => {
               </Stack.Item>
             </Stack>
           </Stack.Item>
-
           <Stack.Divider />
-
           <Stack.Item>{pageContents}</Stack.Item>
         </Stack>
       </Window.Content>