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

import { vi } from 'vitest';
import type { Config } from '../../config/config.js';
import type { ContextEnvironment } from '../sidecar/environment.js';
import type { Content } from '@google/genai';
import { AgentChatHistory } from '../../core/agentChatHistory.js';
import { ContextManager } from '../contextManager.js';

import { InMemoryFileSystem } from '../system/InMemoryFileSystem.js';
import { DeterministicIdGenerator } from '../system/DeterministicIdGenerator.js';
import type { Episode } from '../ir/types.js';
import type { ContextAccountingState } from '../pipeline.js';
import { randomUUID } from 'node:crypto';

export function createDummyState(
  isSatisfied = false,
  deficit = 0,
  protectedIds = new Set<string>(),
  currentTokens = 5000,
  maxTokens = 10000,
  retainedTokens = 4000,
): ContextAccountingState {
  return {
    currentTokens,
    maxTokens,
    retainedTokens,
    deficitTokens: deficit,
    protectedEpisodeIds: protectedIds,
    isBudgetSatisfied: isSatisfied,
  };
}

export function createDummyEpisode(
  id: string,
  type: 'USER_PROMPT' | 'SYSTEM_EVENT',
  parts: unknown[] = [],
  toolSteps: { intent: Record<string, unknown>; observation: Record<string, unknown>; toolName?: string; tokens?: { intent: number; observation: number } }[] = []
): Episode {
  return {
    id,
    timestamp: Date.now(),
    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
    trigger: {
      id: randomUUID(),
      type,
      name: type === 'SYSTEM_EVENT' ? 'dummy_event' : undefined,
      payload: type === 'SYSTEM_EVENT' ? {} : undefined,
      semanticParts: type === 'USER_PROMPT' ? parts as any : undefined,
      metadata: { originalTokens: 100, currentTokens: 100, transformations: [] },
    } as any,
    steps: toolSteps.map(step => ({
      id: randomUUID(),
      type: 'TOOL_EXECUTION',
      toolName: step.toolName || 'test_tool',
      intent: step.intent,
      observation: step.observation,
      tokens: step.tokens || { intent: 50, observation: 50 },
      metadata: { originalTokens: 100, currentTokens: 100, transformations: [] },
    })),
  };
}

export function createMockEnvironment(): ContextEnvironment {
  return {
    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
    llmClient: vi.fn().mockReturnValue({
      generateContent: vi.fn().mockResolvedValue({
        text: 'Mock LLM summary response',
      }),
    })() as unknown as BaseLlmClient,
    promptId: 'mock-prompt-id',
    sessionId: 'mock-session',
    traceDir: '/tmp/.gemini/trace',
    projectTempDir: '/tmp/.gemini/tool-outputs',
    eventBus: new ContextEventBus(),
    tracer: new ContextTracer({ targetDir: '/tmp', sessionId: 'mock-session' }),
    charsPerToken: 1,
    tokenCalculator: new ContextTokenCalculator(1),
    fileSystem: new InMemoryFileSystem(),
    idGenerator: new DeterministicIdGenerator('mock-uuid-'),
  };
}

/**
 * Creates a block of synthetic conversation history designed to consume a specific number of tokens.
 * Assumes roughly 4 characters per token for standard English text.
 */
export function createSyntheticHistory(
  numTurns: number,
  tokensPerTurn: number,
): Content[] {
  const history: Content[] = [];
  const charsPerTurn = tokensPerTurn * 1;

  for (let i = 0; i < numTurns; i++) {
    history.push({
      role: 'user',
      parts: [{ text: `User turn ${i}. ` + 'A'.repeat(charsPerTurn) }],
    });
    history.push({
      role: 'model',
      parts: [{ text: `Model response ${i}. ` + 'B'.repeat(charsPerTurn) }],
    });
  }

  return history;
}

/**
 * Creates a fully mocked Config object tailored for Context Component testing.
 */
export function createMockContextConfig(
  overrides?: Record<string, unknown>,
  llmClientOverride?: unknown,
): Config {
  const defaultConfig = {
    isContextManagementEnabled: vi.fn().mockReturnValue(true),
    storage: {
      getProjectTempDir: vi.fn().mockReturnValue('/tmp/gemini-test'),
    },
    getBaseLlmClient: vi.fn().mockReturnValue(
      llmClientOverride || {
        generateContent: vi.fn().mockResolvedValue({
          text: '<mocked_snapshot>Synthesized state</mocked_snapshot>',
        }),
      },
    ),
    getUsageStatisticsEnabled: vi.fn().mockReturnValue(false),
    getTargetDir: vi.fn().mockReturnValue('/tmp'),
    getSessionId: vi.fn().mockReturnValue('test-session'),
    getExperimentalContextSidecarConfig: vi.fn().mockReturnValue(undefined),
  };

  // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
  return { ...defaultConfig, ...overrides } as unknown as Config;
}

/**
 * Wires up a full ContextManager component with an AgentChatHistory and active background workers.
 */
import { ContextTracer } from '../tracer.js';
import { ContextEnvironmentImpl } from '../sidecar/environmentImpl.js';
import { SidecarLoader } from '../sidecar/SidecarLoader.js';
import { ContextEventBus } from '../eventBus.js';
import { ContextTokenCalculator } from '../utils/contextTokenCalculator.js';
import type { BaseLlmClient } from 'src/core/baseLlmClient.js';

export function setupContextComponentTest(config: Config) {
  const chatHistory = new AgentChatHistory();
  const sidecar = SidecarLoader.fromConfig(config);
  const tracer = new ContextTracer({ targetDir: '/tmp', sessionId: 'test-session' });
  const eventBus = new ContextEventBus();
  const env = new ContextEnvironmentImpl(
    config.getBaseLlmClient(),
    'test prompt-id',
    'test-session',
    '/tmp',
    '/tmp/gemini-test',
    tracer,
    1,
    eventBus
  );
  const contextManager = new ContextManager(sidecar, env, tracer);

  // The async worker is now internally managed by ContextManager

  // Subscribe to history to enable the Eager/Opportunistic triggers
  contextManager.subscribeToHistory(chatHistory);

  return { chatHistory, contextManager };
}