Grudgematch Checkers

Authentication

We leverage Firebase's standard authentication to allow users to create accounts and start playing (with persistant states and progress)

• Note, we don't actually validate the email. It just has to has a valid @.* format
• As per Firebase requirements, passwords have to be >6 characters
• Once an email is used for the first time, it will be stored, and future uses must require the valid password

Lobby

We allow users to choose a name. This step is requested on first-authentication for all users. Once that step is completed, users can input a room ID or create a new room

• However, we don't actually use the name provided anywhere
• We only use accounts for the purpose of turns and state persistance
• Room IDs are obtained by friends after a room is created (it will be displayed in the room). We have no method of joining publicly advertised rooms yet.

Room

Once users join or create a room, they are shown the board, the room ID, actions, and a status message

• The creator of the room moves first by default
• Once a move is made, it can be reverted/undone using the blue undo button.
• When a player is done their move, they can press the green done button to finalize it.
  • Once a move is finalized, Firebase is updated to reflect the new move
  • Non-finalized moves (local, undo-able moves) are not seen by the other player. They are only updated when Firebase's game state is updated.
• The status message indicates who's making the current move.
• The player must wait until his or her opponent is done their move before doing anything else.

Mechanics

• We define an auxiliary set of cells as the cells that a piece can possibly move to
  • These cells include
    • Cells that can be reached by jumping over an enemy
    • Cells that can be reached by a simple one-cell diagonal move
• We use the notion of auxiliary cells to simplify our move-parsing. Instead of checking if a chosen cell is valid for a piece to move to, we simply provide all valid auxiliary cells, and clicks to cells that are not auxiliary are ignored (usually, they de-select the currently selected cell).
  • As such, we only need to consider valid-cell clicks.
• Note, our version uses the non-flying-kings ruleset, where kings can only move backwards, not fly like bishops.