package backend;

import java.util.Stack;

/**
 * This class keeps track of all moves made during a chess game
 * and allows players to undo moves.
 */
public class MoveHistory {
    // Stack data structure to store moves in order (last in, first out)
    private Stack<Move> moveStack;
    
    /**
     * Create a new empty move history
     */
    public MoveHistory() {
        // Initialize an empty stack to store moves
        moveStack = new Stack<>();
    }
    
    /**
     * Add a new move to the history
     * 
     * @param move The chess move to add to history
     */
    public void recordMove(Move move) {
        // Add the move to the top of the stack
        moveStack.push(move);
    }
    
    /**
     * Get the most recent move and remove it from history
     * Used when undoing a move
     * 
     * @return The last move made, or null if no moves exist
     */
    public Move getLastMove() {
        // Check if there are any moves in the history
        if (moveStack.isEmpty()) {
            // If no moves exist, return null
            return null;
        }
        // Remove and return the most recent move
        return moveStack.pop();
    }
    
    /**
     * Check if there are any moves that can be undone
     * 
     * @return True if there are moves in history, false if history is empty
     */
    public boolean canUndo() {
        // Return true if the stack has moves, false if it's empty
        return !moveStack.isEmpty();
    }
    
    /**
     * Remove all moves from the history
     * Used when starting a new game
     */
    public void clear() {
        // Delete all moves from the stack
        moveStack.clear();
    }
}