/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { SchedulerStateManager } from './state-manager.js';
import type {
  ValidatingToolCall,
  WaitingToolCall,
  SuccessfulToolCall,
  ErroredToolCall,
  CancelledToolCall,
  ExecutingToolCall,
  ToolCallRequestInfo,
  ToolCallResponseInfo,
} from './types.js';
import {
  ToolConfirmationOutcome,
  type AnyDeclarativeTool,
  type AnyToolInvocation,
} from '../tools/tools.js';
import { MessageBusType } from '../confirmation-bus/types.js';
import type { MessageBus } from '../confirmation-bus/message-bus.js';
import { ROOT_SCHEDULER_ID } from './types.js';

describe('SchedulerStateManager', () => {
  const mockRequest: ToolCallRequestInfo = {
    callId: 'call-1',
    name: 'test-tool',
    args: { foo: 'bar' },
    isClientInitiated: false,
    prompt_id: 'prompt-1',
  };

  const mockTool = {
    name: 'test-tool',
    displayName: 'Test Tool',
  } as AnyDeclarativeTool;

  const mockInvocation = {
    shouldConfirmExecute: vi.fn(),
  } as unknown as AnyToolInvocation;

  const createValidatingCall = (id = 'call-1'): ValidatingToolCall => ({
    status: 'validating',
    request: { ...mockRequest, callId: id },
    tool: mockTool,
    invocation: mockInvocation,
    startTime: Date.now(),
  });

  const createMockResponse = (id: string): ToolCallResponseInfo => ({
    callId: id,
    responseParts: [],
    resultDisplay: 'Success',
    error: undefined,
    errorType: undefined,
  });

  let stateManager: SchedulerStateManager;
  let mockMessageBus: MessageBus;
  let onUpdate: (calls: unknown[]) => void;

  beforeEach(() => {
    onUpdate = vi.fn();
    mockMessageBus = {
      publish: vi.fn(),
      subscribe: vi.fn(),
      unsubscribe: vi.fn(),
    } as unknown as MessageBus;

    // Capture the update when published
    vi.mocked(mockMessageBus.publish).mockImplementation((msg) => {
      // Return a Promise to satisfy the void | Promise<void> signature if needed,
      // though typically mocks handle it.
      if (msg.type === MessageBusType.TOOL_CALLS_UPDATE) {
        onUpdate(msg.toolCalls);
      }
      return Promise.resolve();
    });

    stateManager = new SchedulerStateManager(mockMessageBus);
  });

  describe('Observer Callback', () => {
    it('should trigger onTerminalCall when finalizing a call', () => {
      const onTerminalCall = vi.fn();
      const manager = new SchedulerStateManager(
        mockMessageBus,
        ROOT_SCHEDULER_ID,
        onTerminalCall,
      );
      const call = createValidatingCall();
      manager.enqueue([call]);
      manager.dequeue();
      manager.updateStatus(
        call.request.callId,
        'success',
        createMockResponse(call.request.callId),
      );
      manager.finalizeCall(call.request.callId);

      expect(onTerminalCall).toHaveBeenCalledTimes(1);
      expect(onTerminalCall).toHaveBeenCalledWith(
        expect.objectContaining({
          status: 'success',
          request: expect.objectContaining({ callId: call.request.callId }),
        }),
      );
    });

    it('should trigger onTerminalCall for every call in cancelAllQueued', () => {
      const onTerminalCall = vi.fn();
      const manager = new SchedulerStateManager(
        mockMessageBus,
        ROOT_SCHEDULER_ID,
        onTerminalCall,
      );
      manager.enqueue([createValidatingCall('1'), createValidatingCall('2')]);

      manager.cancelAllQueued('Test cancel');

      expect(onTerminalCall).toHaveBeenCalledTimes(2);
      expect(onTerminalCall).toHaveBeenCalledWith(
        expect.objectContaining({
          status: 'cancelled',
          request: expect.objectContaining({ callId: '1' }),
        }),
      );
      expect(onTerminalCall).toHaveBeenCalledWith(
        expect.objectContaining({
          status: 'cancelled',
          request: expect.objectContaining({ callId: '2' }),
        }),
      );
    });
  });

  describe('Initialization', () => {
    it('should start with empty state', () => {
      expect(stateManager.isActive).toBe(false);
      expect(stateManager.activeCallCount).toBe(0);
      expect(stateManager.queueLength).toBe(0);
      expect(stateManager.getSnapshot()).toEqual([]);
    });
  });

  describe('Lookup Operations', () => {
    it('should find tool calls in active calls', () => {
      const call = createValidatingCall('active-1');
      stateManager.enqueue([call]);
      stateManager.dequeue();
      expect(stateManager.getToolCall('active-1')).toEqual(call);
    });

    it('should find tool calls in the queue', () => {
      const call = createValidatingCall('queued-1');
      stateManager.enqueue([call]);
      expect(stateManager.getToolCall('queued-1')).toEqual(call);
    });

    it('should find tool calls in the completed batch', () => {
      const call = createValidatingCall('completed-1');
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(
        'completed-1',
        'success',
        createMockResponse('completed-1'),
      );
      stateManager.finalizeCall('completed-1');
      expect(stateManager.getToolCall('completed-1')).toBeDefined();
    });

    it('should return undefined for non-existent callIds', () => {
      expect(stateManager.getToolCall('void')).toBeUndefined();
    });
  });

  describe('Queue Management', () => {
    it('should enqueue calls and notify', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);

      expect(stateManager.queueLength).toBe(1);
      expect(onUpdate).toHaveBeenCalledWith([call]);
    });

    it('should dequeue calls and notify', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);

      const dequeued = stateManager.dequeue();

      expect(dequeued).toEqual(call);
      expect(stateManager.queueLength).toBe(0);
      expect(stateManager.activeCallCount).toBe(1);
      expect(onUpdate).toHaveBeenCalled();
    });

    it('should return undefined when dequeueing from empty queue', () => {
      const dequeued = stateManager.dequeue();
      expect(dequeued).toBeUndefined();
    });
  });

  describe('Status Transitions', () => {
    it('should transition validating to scheduled', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      stateManager.updateStatus(call.request.callId, 'scheduled');

      const snapshot = stateManager.getSnapshot();
      expect(snapshot[0].status).toBe('scheduled');
      expect(snapshot[0].request.callId).toBe(call.request.callId);
    });

    it('should transition scheduled to executing', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(call.request.callId, 'scheduled');

      stateManager.updateStatus(call.request.callId, 'executing');

      expect(stateManager.firstActiveCall?.status).toBe('executing');
    });

    it('should transition to success and move to completed batch', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const response: ToolCallResponseInfo = {
        callId: call.request.callId,
        responseParts: [],
        resultDisplay: 'Success',
        error: undefined,
        errorType: undefined,
      };

      vi.mocked(onUpdate).mockClear();
      stateManager.updateStatus(call.request.callId, 'success', response);
      expect(onUpdate).toHaveBeenCalledTimes(1);

      vi.mocked(onUpdate).mockClear();
      stateManager.finalizeCall(call.request.callId);
      expect(onUpdate).toHaveBeenCalledTimes(1);

      expect(stateManager.isActive).toBe(false);
      expect(stateManager.completedBatch).toHaveLength(1);
      const completed = stateManager.completedBatch[0] as SuccessfulToolCall;
      expect(completed.status).toBe('success');
      expect(completed.response).toEqual(response);
      expect(completed.durationMs).toBeDefined();
    });

    it('should transition to error and move to completed batch', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const response: ToolCallResponseInfo = {
        callId: call.request.callId,
        responseParts: [],
        resultDisplay: 'Error',
        error: new Error('Failed'),
        errorType: undefined,
      };

      stateManager.updateStatus(call.request.callId, 'error', response);
      stateManager.finalizeCall(call.request.callId);

      expect(stateManager.isActive).toBe(false);
      expect(stateManager.completedBatch).toHaveLength(1);
      const completed = stateManager.completedBatch[0] as ErroredToolCall;
      expect(completed.status).toBe('error');
      expect(completed.response).toEqual(response);
    });

    it('should transition to awaiting_approval with details', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const details = {
        type: 'info' as const,
        title: 'Confirm',
        prompt: 'Proceed?',
        onConfirm: vi.fn(),
      };

      stateManager.updateStatus(
        call.request.callId,
        'awaiting_approval',
        details,
      );

      const active = stateManager.firstActiveCall as WaitingToolCall;
      expect(active.status).toBe('awaiting_approval');
      expect(active.confirmationDetails).toEqual(details);
    });

    it('should transition to awaiting_approval with event-driven format', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const details = {
        type: 'info' as const,
        title: 'Confirm',
        prompt: 'Proceed?',
      };
      const eventDrivenData = {
        correlationId: 'corr-123',
        confirmationDetails: details,
      };

      stateManager.updateStatus(
        call.request.callId,
        'awaiting_approval',
        eventDrivenData,
      );

      const active = stateManager.firstActiveCall as WaitingToolCall;
      expect(active.status).toBe('awaiting_approval');
      expect(active.correlationId).toBe('corr-123');
      expect(active.confirmationDetails).toEqual(details);
    });

    it('should preserve diff when cancelling an edit tool call', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const details = {
        type: 'edit' as const,
        title: 'Edit',
        fileName: 'test.txt',
        filePath: '/path/to/test.txt',
        fileDiff: 'diff',
        originalContent: 'old',
        newContent: 'new',
        onConfirm: vi.fn(),
      };

      stateManager.updateStatus(
        call.request.callId,
        'awaiting_approval',
        details,
      );
      stateManager.updateStatus(
        call.request.callId,
        'cancelled',
        'User said no',
      );
      stateManager.finalizeCall(call.request.callId);

      const completed = stateManager.completedBatch[0] as CancelledToolCall;
      expect(completed.status).toBe('cancelled');
      expect(completed.response.resultDisplay).toEqual({
        fileDiff: 'diff',
        fileName: 'test.txt',
        filePath: '/path/to/test.txt',
        originalContent: 'old',
        newContent: 'new',
      });
    });

    it('should ignore status updates for non-existent callIds', () => {
      stateManager.updateStatus('unknown', 'scheduled');
      expect(onUpdate).not.toHaveBeenCalled();
    });

    it('should ignore status updates for terminal calls', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(
        call.request.callId,
        'success',
        createMockResponse(call.request.callId),
      );
      stateManager.finalizeCall(call.request.callId);

      vi.mocked(onUpdate).mockClear();
      stateManager.updateStatus(call.request.callId, 'scheduled');
      expect(onUpdate).not.toHaveBeenCalled();
    });

    it('should only finalize terminal calls', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      stateManager.updateStatus(call.request.callId, 'executing');
      stateManager.finalizeCall(call.request.callId);

      expect(stateManager.isActive).toBe(true);
      expect(stateManager.completedBatch).toHaveLength(0);

      stateManager.updateStatus(
        call.request.callId,
        'success',
        createMockResponse(call.request.callId),
      );
      stateManager.finalizeCall(call.request.callId);

      expect(stateManager.isActive).toBe(false);
      expect(stateManager.completedBatch).toHaveLength(1);
    });

    it('should merge liveOutput and pid during executing updates', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      // Start executing
      stateManager.updateStatus(call.request.callId, 'executing');
      let active = stateManager.firstActiveCall as ExecutingToolCall;
      expect(active.status).toBe('executing');
      expect(active.liveOutput).toBeUndefined();

      // Update with live output
      stateManager.updateStatus(call.request.callId, 'executing', {
        liveOutput: 'chunk 1',
      });
      active = stateManager.firstActiveCall as ExecutingToolCall;
      expect(active.liveOutput).toBe('chunk 1');

      // Update with pid (should preserve liveOutput)
      stateManager.updateStatus(call.request.callId, 'executing', {
        pid: 1234,
      });
      active = stateManager.firstActiveCall as ExecutingToolCall;
      expect(active.liveOutput).toBe('chunk 1');
      expect(active.pid).toBe(1234);

      // Update live output again (should preserve pid)
      stateManager.updateStatus(call.request.callId, 'executing', {
        liveOutput: 'chunk 2',
      });
      active = stateManager.firstActiveCall as ExecutingToolCall;
      expect(active.liveOutput).toBe('chunk 2');
      expect(active.pid).toBe(1234);
    });
  });

  describe('Argument Updates', () => {
    it('should update args and invocation', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      const newArgs = { foo: 'updated' };
      const newInvocation = { ...mockInvocation } as AnyToolInvocation;

      stateManager.updateArgs(call.request.callId, newArgs, newInvocation);

      const active = stateManager.firstActiveCall;
      if (active && 'invocation' in active) {
        expect(active.invocation).toEqual(newInvocation);
      } else {
        throw new Error('Active call should have invocation');
      }
    });

    it('should ignore arg updates for errored calls', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(
        call.request.callId,
        'error',
        createMockResponse(call.request.callId),
      );
      stateManager.finalizeCall(call.request.callId);

      stateManager.updateArgs(
        call.request.callId,
        { foo: 'new' },
        mockInvocation,
      );

      const completed = stateManager.completedBatch[0];
      expect(completed.request.args).toEqual(mockRequest.args);
    });
  });

  describe('Outcome Tracking', () => {
    it('should set outcome and notify', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();

      stateManager.setOutcome(
        call.request.callId,
        ToolConfirmationOutcome.ProceedAlways,
      );

      const active = stateManager.firstActiveCall;
      expect(active?.outcome).toBe(ToolConfirmationOutcome.ProceedAlways);
      expect(onUpdate).toHaveBeenCalled();
    });
  });

  describe('Batch Operations', () => {
    it('should cancel all queued calls', () => {
      stateManager.enqueue([
        createValidatingCall('1'),
        createValidatingCall('2'),
      ]);

      vi.mocked(onUpdate).mockClear();
      stateManager.cancelAllQueued('Batch cancel');

      expect(stateManager.queueLength).toBe(0);
      expect(stateManager.completedBatch).toHaveLength(2);
      expect(
        stateManager.completedBatch.every((c) => c.status === 'cancelled'),
      ).toBe(true);
      expect(onUpdate).toHaveBeenCalledTimes(1);
    });

    it('should not notify if cancelAllQueued is called on an empty queue', () => {
      vi.mocked(onUpdate).mockClear();
      stateManager.cancelAllQueued('Batch cancel');
      expect(onUpdate).not.toHaveBeenCalled();
    });

    it('should clear batch and notify', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(
        call.request.callId,
        'success',
        createMockResponse(call.request.callId),
      );
      stateManager.finalizeCall(call.request.callId);

      stateManager.clearBatch();

      expect(stateManager.completedBatch).toHaveLength(0);
      expect(onUpdate).toHaveBeenCalledWith([]);
    });

    it('should return a copy of the completed batch (defensive)', () => {
      const call = createValidatingCall();
      stateManager.enqueue([call]);
      stateManager.dequeue();
      stateManager.updateStatus(
        call.request.callId,
        'success',
        createMockResponse(call.request.callId),
      );
      stateManager.finalizeCall(call.request.callId);

      const batch = stateManager.completedBatch;
      expect(batch).toHaveLength(1);

      // Mutate the returned array
      batch.pop();
      expect(batch).toHaveLength(0);

      // Verify internal state is unchanged
      expect(stateManager.completedBatch).toHaveLength(1);
    });
  });

  describe('Snapshot and Ordering', () => {
    it('should return snapshot in order: completed, active, queue', () => {
      // 1. Completed
      const call1 = createValidatingCall('1');
      stateManager.enqueue([call1]);
      stateManager.dequeue();
      stateManager.updateStatus('1', 'success', createMockResponse('1'));
      stateManager.finalizeCall('1');

      // 2. Active
      const call2 = createValidatingCall('2');
      stateManager.enqueue([call2]);
      stateManager.dequeue();

      // 3. Queue
      const call3 = createValidatingCall('3');
      stateManager.enqueue([call3]);

      const snapshot = stateManager.getSnapshot();
      expect(snapshot).toHaveLength(3);
      expect(snapshot[0].request.callId).toBe('1');
      expect(snapshot[1].request.callId).toBe('2');
      expect(snapshot[2].request.callId).toBe('3');
    });
  });
});