Action Management/Game State - Item Stacking Design

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Introduction

Currently, an item has to have a unique item_id to be added to the following:

• A game
• A player's inventory
• A room
• An NPC's inventory

This wiki concerns itself with developing a design to allow multiple items with identical item_ids to be added to these containers.

Some notes:

• Items with the same item_id should NOT have to be otherwise identical; for example, there could be two items with item_id "apple," but one has the effect of increasing HP when eaten and one has the effect of poisoning the player when eaten
  • That being said, two completely identical objects should be allowed in the same container
• Contact the NPC team to inform them of any changes that may become necessary for their functions.
• For reference while coding: uthash User Guide, utlist information

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Design Plan

• Add a field to the item_t struct - a pointer to another item
  • This pointer points to an item with the same item_id as the current item
• Add two new functions to item.h: add_item_to_hash and remove_item_from_hash
  • When adding an item, remove the current hashtable entry, have the new item point to this item, and store the new item in the hashtable
    • Note that if there is not already an item at this hashtable entry, the new item will just be pointing to NULL
  • When removing an item, store what the item is pointing to in the hashtable
    • Note that if the item is not pointing to another item, the new hashtable entry will just be NULL
    • Afterwards, set the item being removed to be pointing to NULL
• Replace the body add_item_to_[blank] functions with a call to add_item_to_hash
  • Will be necessary to unwrap the item hashtable from the passed struct first
• Add functions to remove an item_t from a game/room/inventory:
  • Similar to the add_item_to_[blank] functions, simply call remove_item_from_hash after unwrapping the item hashtable
• Add a function to convert an item hashtable to an item linked-list
  • Add item to list
  • Check if item's next != NULL
  • If so, iterate to next item and repeat
• When performing an action on an item:
  • Try action on head of the list (passed as the item to do_[blank]_action)
  • If possible_action, all_conditions_met, and do_all_effects all fail, and item's next != NULL, try again with the next pointer

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To-Do:

• Merge PR

Completed:

• REFACTORING:
  • Wrote add_item_to_hash function & updated code that uses identical functionality
  • Wrote remove_item_from_hash functions
  • Wrote functions to remove item from game/room/player inventory/NPC inventory (using remove_item_from_hash functions)
  • Wrote get_all_items_in_hash function & updated code that uses identical functionality
  • Wrote/updated tests for refactored code
• ITEM STACKING IMPLEMENTATION:
  • Edited item struct with a pointer to another item
  • Updated add_item_to_hash to take pointer into account
  • Updated get_all_items_in_hash to take pointer into account
  • Updated remove_item_from_hash to take pointer into account
  • Reworked kind1_action_operation and kind3_action_operation to check all identical items if anything fails
  • Updated look_operation (operations.c) to mention there being multiple of an item
  • Wrote/updated tests for handling items with identical ids in the various item hashtable functions