boardgame-core/tests/core/game-host.test.ts

import { describe, it, expect } from 'vitest';
import {
    registry,
    createInitialState,
    TicTacToeState,
    WinnerType,
    PlayerType
} from '@/samples/tic-tac-toe';
import { createGameHost, GameHost } from '@/core/game-host';
import type { PromptEvent } from '@/utils/command';
import { MutableSignal } from '@/utils/mutable-signal';

function createTestHost() {
    const host = createGameHost(
        { registry, createInitialState }
    );
    return { host };
}

function waitForPromptEvent(host: GameHost<any>): Promise<PromptEvent> {
    return new Promise(resolve => {
        host.context._commands.on('prompt', resolve);
    });
}

describe('GameHost', () => {
    describe('creation', () => {
        it('should create host with initial state', () => {
            const { host } = createTestHost();

            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(host.context._state.value.winner).toBeNull();
            expect(host.context._state.value.turn).toBe(0);
            expect(Object.keys(host.context._state.value.parts).length).toBe(0);
        });

        it('should have status "created" by default', () => {
            const { host } = createTestHost();

            expect(host.status.value).toBe('created');
        });

        it('should have null activePromptSchema initially', () => {
            const { host } = createTestHost();

            expect(host.activePromptSchema.value).toBeNull();
        });
    });

    describe('onInput', () => {
        it('should return "No active prompt" when no prompt is active', () => {
            const { host } = createTestHost();

            const result = host.onInput('play X 1 1');
            expect(result).toBe('No active prompt');
        });

        it('should accept valid input when prompt is active', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            const promptEvent = await promptPromise;
            expect(promptEvent.schema.name).toBe('play');
            expect(host.activePromptSchema.value?.name).toBe('play');

            const error = host.onInput('play X 1 1');
            expect(error).toBeNull();

            // Cancel to end the game since setup runs until game over
            const nextPromptPromise = waitForPromptEvent(host);
            const nextPrompt = await nextPromptPromise;
            nextPrompt.cancel('test cleanup');

            const result = await runPromise;
            expect(result.success).toBe(false); // Cancelled
        });

        it('should reject invalid input', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            const promptEvent = await promptPromise;

            const error = host.onInput('invalid command');
            expect(error).not.toBeNull();

            promptEvent.cancel('test cleanup');
            await runPromise;
        });

        it('should return error when disposed', () => {
            const { host } = createTestHost();
            host.dispose();

            const result = host.onInput('play X 1 1');
            expect(result).toBe('GameHost is disposed');
        });
    });

    describe('getActivePromptSchema', () => {
        it('should return schema when prompt is active', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            const promptEvent = await promptPromise;
            const schema = host.activePromptSchema.value;

            expect(schema).not.toBeNull();
            expect(schema?.name).toBe('play');

            promptEvent.cancel('test cleanup');
            await runPromise;
        });

        it('should return null when no prompt is active', () => {
            const { host } = createTestHost();

            expect(host.activePromptSchema.value).toBeNull();
        });
    });

    describe('setup', () => {
        it('should reset state and run setup command', async () => {
            const { host } = createTestHost();

            // First setup - make one move
            let promptPromise = waitForPromptEvent(host);
            let runPromise = host.context._commands.run('setup');
            let promptEvent = await promptPromise;
            
            // Make a move
            promptEvent.tryCommit({ name: 'play', params: ['X', 1, 1], options: {}, flags: {} });
            
            // Wait for next prompt (next turn) and cancel
            promptPromise = waitForPromptEvent(host);
            promptEvent = await promptPromise;
            promptEvent.cancel('test end');
            
            let result = await runPromise;
            expect(result.success).toBe(false); // Cancelled
            expect(Object.keys(host.context._state.value.parts).length).toBe(1);

            // Setup listener before calling setup
            const newPromptPromise = waitForPromptEvent(host);
            
            // Reset - should reset state and start new game
            host.setup('setup');

            // State should be back to initial
            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(host.context._state.value.winner).toBeNull();
            expect(host.context._state.value.turn).toBe(0);
            expect(Object.keys(host.context._state.value.parts).length).toBe(0);
            
            // New game should be running and prompting
            const newPrompt = await newPromptPromise;
            expect(newPrompt.schema.name).toBe('play');
            newPrompt.cancel('test end');
        });

        it('should cancel active prompt during setup', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            await promptPromise;

            // Setup should cancel the active prompt and reset state
            host.setup('setup');

            // The original runPromise should be rejected due to cancellation
            try {
                await runPromise;
            } catch (e) {
                const error = e as Error;
                expect(error.message).toContain('Cancelled');
            }
            
            // State should be reset
            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(host.context._state.value.turn).toBe(0);
        });

        it('should throw error when disposed', () => {
            const { host } = createTestHost();
            host.dispose();

            expect(() => host.setup('setup')).toThrow('GameHost is disposed');
        });
    });

    describe('dispose', () => {
        it('should change status to disposed', () => {
            const { host } = createTestHost();
            host.dispose();

            expect(host.status.value).toBe('disposed');
        });

        it('should cancel active prompt on dispose', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            await promptPromise;

            host.dispose();

            // The runPromise should be rejected due to cancellation
            try {
                await runPromise;
            } catch (e) {
                const error = e as Error;
                expect(error.message).toContain('Cancelled');
            }
        });

        it('should be idempotent', () => {
            const { host } = createTestHost();
            host.dispose();
            host.dispose(); // Should not throw

            expect(host.status.value).toBe('disposed');
        });
    });

    describe('events', () => {
        it('should emit setup event', async () => {
            const { host } = createTestHost();

            let setupCount = 0;
            host.on('setup', () => {
                setupCount++;
            });
            
            // Setup listener before calling setup
            const promptPromise = waitForPromptEvent(host);

            // Initial setup via reset
            host.setup('setup');
            expect(setupCount).toBe(1);

            // State should be running
            expect(host.status.value).toBe('running');
            
            // Cancel the background setup command
            const prompt = await promptPromise;
            prompt.cancel('test end');
        });

        it('should emit dispose event', () => {
            const { host } = createTestHost();

            let disposeCount = 0;
            host.on('dispose', () => {
                disposeCount++;
            });

            host.dispose();
            expect(disposeCount).toBe(1);
        });

        it('should allow unsubscribing from events', () => {
            const { host } = createTestHost();

            let setupCount = 0;
            const unsubscribe = host.on('setup', () => {
                setupCount++;
            });

            unsubscribe();

            // No event should be emitted
            // (we can't easily test this without triggering setup, but we verify unsubscribe works)
            expect(typeof unsubscribe).toBe('function');
        });
    });

    describe('reactive state', () => {
        it('should have state that reflects game progress', async () => {
            const { host } = createTestHost();

            // Initial state
            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(host.context._state.value.turn).toBe(0);

            // Make a move
            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            const promptEvent = await promptPromise;
            promptEvent.tryCommit({ name: 'play', params: ['X', 1, 1], options: {}, flags: {} });
            
            // Wait for next prompt and cancel
            const nextPromptPromise = waitForPromptEvent(host);
            const nextPrompt = await nextPromptPromise;
            nextPrompt.cancel('test end');
            
            const result = await runPromise;
            expect(result.success).toBe(false); // Cancelled

            expect(host.context._state.value.currentPlayer).toBe('O');
            expect(host.context._state.value.turn).toBe(1);
            expect(Object.keys(host.context._state.value.parts).length).toBe(1);
        });

        it('should update activePromptSchema reactively', async () => {
            const { host } = createTestHost();

            // Initially null
            expect(host.activePromptSchema.value).toBeNull();

            // Start a command that triggers prompt
            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            await promptPromise;

            // Now schema should be set
            expect(host.activePromptSchema.value).not.toBeNull();
            expect(host.activePromptSchema.value?.name).toBe('play');

            // Cancel and wait
            const cancelEvent = host.activePromptSchema.value;
            host.context._commands._cancel();
            try {
                await runPromise;
            } catch {
                // Expected
            }

            // Schema should be null again
            expect(host.activePromptSchema.value).toBeNull();
        });
    });

    describe('full game', () => {
        it('should run a complete game of tic-tac-toe with X winning diagonally', async () => {
            const { host } = createTestHost();

            // Initial state
            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(host.context._state.value.winner).toBeNull();
            expect(host.context._state.value.turn).toBe(0);
            expect(Object.keys(host.context._state.value.parts).length).toBe(0);

            // X wins diagonally: (0,0), (1,1), (2,2)
            // O plays: (0,1), (2,1)
            const moves = [
                'play X 0 0', // turn 1: X
                'play O 0 1', // turn 2: O
                'play X 1 1', // turn 3: X
                'play O 2 1', // turn 4: O
                'play X 2 2', // turn 5: X wins!
            ];

            // Track prompt events in a queue
            const promptEvents: PromptEvent[] = [];
            host.context._commands.on('prompt', (e) => {
                promptEvents.push(e);
            });

            // Start setup command (runs game loop until completion)
            const setupPromise = host.context._commands.run('setup');

            for (let i = 0; i < moves.length; i++) {
                // Wait until the next prompt event arrives
                while (i >= promptEvents.length) {
                    await new Promise(r => setTimeout(r, 10));
                }

                const promptEvent = promptEvents[i];
                expect(promptEvent.schema.name).toBe('play');

                // Submit the move
                const error = host.onInput(moves[i]);
                expect(error).toBeNull();
            }

            // Wait for setup to complete (game ended with winner)
            const result = await setupPromise;
            expect(result.success).toBe(true);
            if (result.success) {
                expect(result.result.winner).toBe('X');
            }

            // Final state checks
            expect(host.context._state.value.winner).toBe('X');
            expect(host.context._state.value.currentPlayer).toBe('X');
            expect(Object.keys(host.context._state.value.parts).length).toBe(5);

            // Verify winning diagonal
            const parts = Object.values(host.context._state.value.parts);
            const xPieces = parts.filter(p => p.player === 'X');
            expect(xPieces).toHaveLength(3);
            expect(xPieces.some(p => JSON.stringify(p.position) === JSON.stringify([0, 0]))).toBe(true);
            expect(xPieces.some(p => JSON.stringify(p.position) === JSON.stringify([1, 1]))).toBe(true);
            expect(xPieces.some(p => JSON.stringify(p.position) === JSON.stringify([2, 2]))).toBe(true);

            host.dispose();
            expect(host.status.value).toBe('disposed');
        });
    });

    describe('currentPlayer in prompt', () => {
        it('should have currentPlayer in PromptEvent', async () => {
            const { host } = createTestHost();

            const promptPromise = waitForPromptEvent(host);
            const runPromise = host.context._commands.run('setup');

            const promptEvent = await promptPromise;
            expect(promptEvent.currentPlayer).toBe('X');
            expect(host.activePromptPlayer.value).toBe('X');

            promptEvent.cancel('test cleanup');
            await runPromise;
        });

        it('should update activePromptPlayer reactively', async () => {
            const { host } = createTestHost();

            // Initially null
            expect(host.activePromptPlayer.value).toBeNull();

            // First prompt - X's turn
            let promptPromise = waitForPromptEvent(host);
            let runPromise = host.context._commands.run('setup');
            let promptEvent = await promptPromise;
            expect(promptEvent.currentPlayer).toBe('X');
            expect(host.activePromptPlayer.value).toBe('X');

            // Make a move
            promptEvent.tryCommit({ name: 'play', params: ['X', 1, 1], options: {}, flags: {} });

            // Second prompt - O's turn
            promptPromise = waitForPromptEvent(host);
            promptEvent = await promptPromise;
            expect(promptEvent.currentPlayer).toBe('O');
            expect(host.activePromptPlayer.value).toBe('O');

            // Cancel
            promptEvent.cancel('test cleanup');
            await runPromise;

            // After prompt ends, player should be null
            expect(host.activePromptPlayer.value).toBeNull();
        });
    });
});