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

import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
import { SimulationHarness } from './SimulationHarness.js';
import { createMockLlmClient } from '../testing/contextTestUtils.js';
import type { SidecarConfig } from '../sidecar/types.js';

expect.addSnapshotSerializer({
  test: (val) =>
    typeof val === 'string' &&
    (/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(
      val,
    ) ||
      /^\/tmp\/sim/.test(val)), // Mask temp directories and UUIDs
  print: (val) =>
    typeof val === 'string' && /^\/tmp\/sim/.test(val)
      ? '"<MOCKED_DIR>"'
      : '"<UUID>"',
});

describe('System Lifecycle Golden Tests', () => {
  beforeAll(() => {
    vi.spyOn(Math, 'random').mockReturnValue(0.5);
  });

  afterAll(() => {
    vi.restoreAllMocks();
  });

  const getAggressiveConfig = (): SidecarConfig => ({
    budget: { maxTokens: 1000, retainedTokens: 500 }, // Extremely tight limits
    pipelines: [
      {
        name: 'Pressure Relief', // Emits from eventBus 'retained_exceeded'
        triggers: ['retained_exceeded'],
        processors: [
          { processorId: 'BlobDegradationProcessor' },
          {
            processorId: 'ToolMaskingProcessor',
            options: { stringLengthThresholdTokens: 50 },
          }, // Mask any tool string > 50 chars
          { processorId: 'StateSnapshotProcessor', options: {} }, // Squash old history
        ],
      },
      {
        name: 'Immediate Sanitization', // The magic string the projector is hardcoded to use
        triggers: ['retained_exceeded'],
        processors: [
          { processorId: 'HistoryTruncationProcessor', options: {} },
        ],
      },
    ],
    workers: [
      { workerId: 'StateSnapshotWorker' }
    ]
  });

  const mockLlmClient = createMockLlmClient([
    '<MOCKED_STATE_SNAPSHOT_SUMMARY>',
  ]);

  it('Scenario 1: Organic Growth with Huge Tool Output & Images', async () => {
    const harness = await SimulationHarness.create(
      getAggressiveConfig(),
      mockLlmClient,
    );

    // Turn 0: System Prompt
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'System Instructions' }] },
      { role: 'model', parts: [{ text: 'Ack.' }] },
    ]);

    // Turn 1: Normal conversation
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'Hello!' }] },
      { role: 'model', parts: [{ text: 'Hi, how can I help?' }] },
    ]);

    // Turn 2: Massive Tool Output (Should trigger ToolMaskingProcessor in background)
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'Read the logs.' }] },
      {
        role: 'model',
        parts: [
          {
            functionCall: {
              name: 'run_shell_command',
              args: { cmd: 'cat server.log' },
            },
          },
        ],
      },
      {
        role: 'user',
        parts: [
          {
            functionResponse: {
              name: 'run_shell_command',
              response: { output: 'LOG '.repeat(5000) },
            },
          },
        ],
      },
      { role: 'model', parts: [{ text: 'The logs are very long.' }] },
    ]);

    // Turn 3: Multi-modal blob (Should trigger BlobDegradationProcessor)
    await harness.simulateTurn([
      {
        role: 'user',
        parts: [
          { text: 'Look at this architecture diagram:' },
          {
            inlineData: {
              mimeType: 'image/png',
              data: 'fake_base64_data_'.repeat(1000),
            },
          },
        ],
      },
      { role: 'model', parts: [{ text: 'Nice diagram.' }] },
    ]);

    // Turn 4: More conversation to trigger StateSnapshot
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'Can we refactor?' }] },
      { role: 'model', parts: [{ text: 'Yes we can.' }] },
    ]);

    // Get final state
    const goldenState = await harness.getGoldenState();

    // In a perfectly functioning opportunistic system, the token trajectory should show
    // the massive spikes in Turn 2 and 3 being immediately resolved by the background tasks.
    // The final projection should fit neatly under the Max Tokens limit.

    expect(goldenState).toMatchSnapshot();
  });

  it('Scenario 2: Under Budget (No Modifications)', async () => {
    const generousConfig: SidecarConfig = {
      budget: { maxTokens: 100000, retainedTokens: 50000 },
      pipelines: [], // No triggers
      workers: []
    };
    
    const harness = await SimulationHarness.create(
      generousConfig,
      mockLlmClient,
    );

    // Turn 0: System Prompt
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'System Instructions' }] },
      { role: 'model', parts: [{ text: 'Ack.' }] },
    ]);

    // Turn 1: Normal conversation
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'Hello!' }] },
      { role: 'model', parts: [{ text: 'Hi, how can I help?' }] },
    ]);

    const goldenState = await harness.getGoldenState();
    
    // Total tokens should cleanly match character count with no synthetic nodes
    expect(goldenState).toMatchSnapshot();
  });

  it('Scenario 3: Worker-Driven Background GC', async () => {
    const gcConfig: SidecarConfig = {
      budget: { maxTokens: 200, retainedTokens: 100 },
      pipelines: [], // No standard pipelines
      workers: [
        { workerId: 'StateSnapshotWorker' } // This should fire on chunk events
      ]
    };
    
    const harness = await SimulationHarness.create(
      gcConfig,
      mockLlmClient,
    );

    // Turn 0
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'A'.repeat(50) }] },
      { role: 'model', parts: [{ text: 'B'.repeat(50) }] },
    ]);

    // Turn 1 (Should trigger StateSnapshotWorker because we exceed 100 retainedTokens)
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'C'.repeat(50) }] },
      { role: 'model', parts: [{ text: 'D'.repeat(50) }] },
    ]);

    // Give the background worker an extra beat to complete its async execution and emit variants
    await new Promise((resolve) => setTimeout(resolve, 50));

    // Turn 2
    await harness.simulateTurn([
      { role: 'user', parts: [{ text: 'E'.repeat(50) }] },
      { role: 'model', parts: [{ text: 'F'.repeat(50) }] },
    ]);

    const goldenState = await harness.getGoldenState();
    
    // We should see ROLLING_SUMMARY nodes injected into the graph, proving the worker ran in the background
    expect(goldenState).toMatchSnapshot();
  });
});