import { describe, it, expect, vi } from 'vitest';
import { ChatService, MAX_ITERATIONS, TOOL_NAME_SEPARATOR, type ChatToolDispatcher } from '../src/services/chat.service.js';
import type { AgentService } from '../src/services/agent.service.js';
import type { LlmService } from '../src/services/llm.service.js';
import type { LlmAdapterRegistry } from '../src/services/llm/dispatcher.js';
import type { LlmAdapter, NonStreamingResult, InferContext } from '../src/services/llm/types.js';
import type { IChatRepository } from '../src/repositories/chat.repository.js';
import type { IPromptRepository } from '../src/repositories/prompt.repository.js';
import type { ChatMessage, ChatThread, Prompt } from '@prisma/client';

const NOW = new Date();

function mockChatRepo(): IChatRepository & { _msgs: ChatMessage[]; _threads: ChatThread[] } {
  const msgs: ChatMessage[] = [];
  const threads: ChatThread[] = [];
  let idCounter = 1;

  return {
    _msgs: msgs,
    _threads: threads,
    createThread: vi.fn(async ({ agentId, ownerId, title }) => {
      const t: ChatThread = {
        id: `thread-${String(idCounter++)}`,
        agentId,
        ownerId,
        title: title ?? '',
        lastTurnAt: NOW,
        createdAt: NOW,
        updatedAt: NOW,
      };
      threads.push(t);
      return t;
    }),
    findThread: vi.fn(async (id: string) => threads.find((t) => t.id === id) ?? null),
    listThreadsByAgent: vi.fn(async (agentId: string) => threads.filter((t) => t.agentId === agentId)),
    listMessages: vi.fn(async (threadId: string) =>
      msgs.filter((m) => m.threadId === threadId).sort((a, b) => a.turnIndex - b.turnIndex)),
    appendMessage: vi.fn(async (input) => {
      const turnIndex = input.turnIndex ?? msgs.filter((m) => m.threadId === input.threadId).length;
      const m: ChatMessage = {
        id: `msg-${String(idCounter++)}`,
        threadId: input.threadId,
        turnIndex,
        role: input.role,
        content: input.content,
        toolCalls: (input.toolCalls ?? null) as ChatMessage['toolCalls'],
        toolCallId: input.toolCallId ?? null,
        status: input.status ?? 'complete',
        createdAt: NOW,
      };
      msgs.push(m);
      return m;
    }),
    updateStatus: vi.fn(async (id: string, status) => {
      const m = msgs.find((x) => x.id === id);
      if (!m) throw new Error('not found');
      m.status = status;
      return m;
    }),
    markPendingAsError: vi.fn(async (threadId: string) => {
      let n = 0;
      for (const m of msgs) {
        if (m.threadId === threadId && m.status === 'pending') {
          m.status = 'error';
          n += 1;
        }
      }
      return n;
    }),
    touchThread: vi.fn(async () => undefined),
    nextTurnIndex: vi.fn(async (threadId: string) =>
      msgs.filter((m) => m.threadId === threadId).length),
  };
}

function mockPromptRepo(rows: Prompt[] = []): IPromptRepository {
  return {
    findAll: vi.fn(async () => rows),
    findGlobal: vi.fn(async () => rows.filter((p) => p.projectId === null)),
    findById: vi.fn(async (id: string) => rows.find((p) => p.id === id) ?? null),
    findByNameAndProject: vi.fn(async () => null),
    create: vi.fn(),
    update: vi.fn(),
    delete: vi.fn(),
  } as unknown as IPromptRepository;
}

function mockTools(impl: Partial<ChatToolDispatcher> = {}): ChatToolDispatcher {
  return {
    listTools: impl.listTools ?? vi.fn(async () => []),
    callTool: impl.callTool ?? vi.fn(async () => ({ ok: true })),
  };
}

function mockAgents(): AgentService {
  return {
    getByName: vi.fn(async (name: string) => ({
      id: `agent-${name}`,
      name,
      description: 'desc',
      systemPrompt: 'You are a helpful agent.',
      llm: { id: 'llm-1', name: 'qwen3-thinking' },
      project: name === 'no-project'
        ? null
        : { id: 'proj-1', name: 'mcpctl-dev' },
      proxyModelName: null,
      defaultParams: { temperature: 0.5 },
      extras: {},
      ownerId: 'owner-1',
      version: 1,
      createdAt: NOW,
      updatedAt: NOW,
    })),
  } as unknown as AgentService;
}

function mockLlms(): LlmService {
  return {
    getByName: vi.fn(async (name: string) => ({
      id: 'llm-1', name, type: 'openai', model: 'qwen3-thinking',
      url: '', tier: 'fast', description: '',
      apiKeyRef: null, extraConfig: {},
      version: 1, createdAt: NOW, updatedAt: NOW,
    })),
    resolveApiKey: vi.fn(async () => 'fake-key'),
  } as unknown as LlmService;
}

/** Adapter that yields a scripted sequence of canned responses, one per call. */
function scriptedAdapter(responses: NonStreamingResult[]): LlmAdapter {
  let i = 0;
  return {
    kind: 'scripted',
    infer: vi.fn(async (_ctx: InferContext) => {
      const r = responses[i] ?? responses[responses.length - 1];
      i += 1;
      if (r === undefined) throw new Error('no scripted response');
      return r;
    }),
    stream: async function*(_ctx: InferContext) {
      yield { data: '[DONE]', done: true };
    },
  };
}

function adapterRegistry(adapter: LlmAdapter): LlmAdapterRegistry {
  return { get: () => adapter } as unknown as LlmAdapterRegistry;
}

function chatCompletion(content: string): NonStreamingResult {
  return {
    status: 200,
    body: {
      id: 'cmpl-1',
      object: 'chat.completion',
      choices: [{ index: 0, message: { role: 'assistant', content }, finish_reason: 'stop' }],
    },
  };
}

function toolCall(name: string, args: Record<string, unknown>): NonStreamingResult {
  return {
    status: 200,
    body: {
      id: 'cmpl-1',
      object: 'chat.completion',
      choices: [{
        index: 0,
        message: {
          role: 'assistant',
          content: '',
          tool_calls: [{
            id: `call-${name}`,
            type: 'function',
            function: { name, arguments: JSON.stringify(args) },
          }],
        },
        finish_reason: 'tool_calls',
      }],
    },
  };
}

describe('ChatService', () => {
  it('plain text turn — persists user + assistant rows and returns the reply', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([chatCompletion('hello back')]);
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), mockTools(),
    );

    const result = await svc.chat({
      agentName: 'reviewer',
      userMessage: 'hi',
      ownerId: 'owner-1',
    });

    expect(result.assistant).toBe('hello back');
    const stored = chatRepo._msgs.filter((m) => m.threadId === result.threadId);
    expect(stored.map((m) => m.role)).toEqual(['user', 'assistant']);
    expect(stored[1]?.status).toBe('complete');
  });

  it('runs a full tool-use round-trip and ends with a text reply', async () => {
    const chatRepo = mockChatRepo();
    const tools = mockTools({
      listTools: vi.fn(async () => [{
        name: `grafana${TOOL_NAME_SEPARATOR}query`,
        description: 'query grafana',
        parameters: { type: 'object', properties: {} },
      }]),
      callTool: vi.fn(async () => ({ rows: [{ value: 42 }] })),
    });
    const adapter = scriptedAdapter([
      toolCall(`grafana${TOOL_NAME_SEPARATOR}query`, { q: 'cpu' }),
      chatCompletion('the answer is 42'),
    ]);
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );

    const result = await svc.chat({
      agentName: 'reviewer',
      userMessage: 'what is cpu?',
      ownerId: 'owner-1',
    });

    expect(result.assistant).toBe('the answer is 42');
    expect(tools.callTool).toHaveBeenCalledWith({
      projectId: 'proj-1',
      serverName: 'grafana',
      toolName: 'query',
      args: { q: 'cpu' },
    });
    const stored = chatRepo._msgs.filter((m) => m.threadId === result.threadId);
    expect(stored.map((m) => m.role)).toEqual(['user', 'assistant', 'tool', 'assistant']);
    // No `pending` rows leaked.
    expect(stored.every((m) => m.status === 'complete')).toBe(true);
    // Tool turn's toolCallId links back.
    const toolTurn = stored.find((m) => m.role === 'tool');
    expect(toolTurn?.toolCallId).toBe(`call-grafana${TOOL_NAME_SEPARATOR}query`);
  });

  it('caps the loop at MAX_ITERATIONS when the model never settles', async () => {
    const chatRepo = mockChatRepo();
    const tools = mockTools({
      listTools: vi.fn(async () => [{
        name: `g${TOOL_NAME_SEPARATOR}t`,
        description: '',
        parameters: { type: 'object' },
      }]),
      callTool: vi.fn(async () => ({})),
    });
    // Always return a tool_call → the loop never reaches a terminal turn.
    const adapter = scriptedAdapter([toolCall(`g${TOOL_NAME_SEPARATOR}t`, {})]);
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );

    await expect(svc.chat({
      agentName: 'reviewer',
      userMessage: 'loop forever',
      ownerId: 'owner-1',
    })).rejects.toThrow(new RegExp(`exceeded ${String(MAX_ITERATIONS)}`));

    // After failure, no row should remain `pending`.
    expect(chatRepo._msgs.every((m) => m.status !== 'pending')).toBe(true);
  });

  it('flips pending rows to error when the adapter throws mid-loop', async () => {
    const chatRepo = mockChatRepo();
    const tools = mockTools({
      listTools: vi.fn(async () => [{
        name: `g${TOOL_NAME_SEPARATOR}t`, description: '', parameters: {},
      }]),
      callTool: vi.fn(async () => ({})),
    });
    const adapter: LlmAdapter = {
      kind: 'fail-after-one',
      infer: vi.fn()
        .mockResolvedValueOnce(toolCall(`g${TOOL_NAME_SEPARATOR}t`, {}))
        .mockRejectedValueOnce(new Error('upstream blew up')),
      stream: async function*() { yield { data: '[DONE]', done: true }; },
    };
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );

    await expect(svc.chat({
      agentName: 'reviewer',
      userMessage: 'go',
      ownerId: 'owner-1',
    })).rejects.toThrow('upstream blew up');

    expect(chatRepo._msgs.some((m) => m.status === 'error')).toBe(false);
    expect(chatRepo._msgs.every((m) => m.status !== 'pending')).toBe(true);
  });

  it('merges per-call params over agent.defaultParams (override wins)', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([chatCompletion('ok')]);
    const inferSpy = adapter.infer as ReturnType<typeof vi.fn>;
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), mockTools(),
    );
    await svc.chat({
      agentName: 'reviewer',
      userMessage: 'hi',
      ownerId: 'owner-1',
      params: { temperature: 0.9, max_tokens: 256 },
    });
    const ctx = inferSpy.mock.calls[0][0] as InferContext;
    expect(ctx.body.temperature).toBe(0.9);
    expect(ctx.body.max_tokens).toBe(256);
  });

  it('forwards `extra` keys into the body for provider-specific knobs', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([chatCompletion('ok')]);
    const inferSpy = adapter.infer as ReturnType<typeof vi.fn>;
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), mockTools(),
    );
    await svc.chat({
      agentName: 'reviewer',
      userMessage: 'hi',
      ownerId: 'owner-1',
      params: { extra: { metadata: { user_id: 'abc' }, repetition_penalty: 1.05 } },
    });
    const ctx = inferSpy.mock.calls[0][0] as InferContext;
    expect((ctx.body as Record<string, unknown>)['repetition_penalty']).toBe(1.05);
    expect((ctx.body as Record<string, unknown>)['metadata']).toEqual({ user_id: 'abc' });
  });

  it('builds a system block from agent.systemPrompt + project prompts (priority desc)', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([chatCompletion('ok')]);
    const inferSpy = adapter.infer as ReturnType<typeof vi.fn>;
    const prompts: Prompt[] = [
      {
        id: 'p1', name: 'low', content: 'LOW prompt',
        projectId: 'proj-1', priority: 1, summary: null, chapters: null,
        linkTarget: null, version: 1, createdAt: NOW, updatedAt: NOW,
      },
      {
        id: 'p2', name: 'high', content: 'HIGH prompt',
        projectId: 'proj-1', priority: 9, summary: null, chapters: null,
        linkTarget: null, version: 1, createdAt: NOW, updatedAt: NOW,
      },
    ];
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(prompts), mockTools(),
    );
    await svc.chat({ agentName: 'reviewer', userMessage: 'hi', ownerId: 'owner-1' });
    const ctx = inferSpy.mock.calls[0][0] as InferContext;
    const sys = ctx.body.messages.find((m) => m.role === 'system');
    expect(typeof sys?.content).toBe('string');
    const text = sys?.content as string;
    // High-priority prompt comes before low-priority.
    expect(text.indexOf('HIGH prompt')).toBeLessThan(text.indexOf('LOW prompt'));
    // Agent's own system prompt leads.
    expect(text.indexOf('You are a helpful agent.')).toBeLessThan(text.indexOf('HIGH prompt'));
  });

  it('refuses tool calls when the agent has no project attached', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([toolCall(`x${TOOL_NAME_SEPARATOR}y`, {})]);
    const tools = mockTools({
      listTools: vi.fn(async () => [{ name: `x${TOOL_NAME_SEPARATOR}y`, description: '', parameters: {} }]),
    });
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );
    await expect(svc.chat({
      agentName: 'no-project',
      userMessage: 'go',
      ownerId: 'owner-1',
    })).rejects.toThrow(/Project/);
  });

  it('honours tools_allowlist (filters tools before sending to adapter)', async () => {
    const chatRepo = mockChatRepo();
    const adapter = scriptedAdapter([chatCompletion('ok')]);
    const inferSpy = adapter.infer as ReturnType<typeof vi.fn>;
    const tools = mockTools({
      listTools: vi.fn(async () => [
        { name: `s1${TOOL_NAME_SEPARATOR}a`, description: '', parameters: {} },
        { name: `s1${TOOL_NAME_SEPARATOR}b`, description: '', parameters: {} },
      ]),
    });
    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );
    await svc.chat({
      agentName: 'reviewer',
      userMessage: 'hi',
      ownerId: 'owner-1',
      params: { tools_allowlist: [`s1${TOOL_NAME_SEPARATOR}a`] },
    });
    const ctx = inferSpy.mock.calls[0][0] as InferContext;
    expect(ctx.body.tools).toHaveLength(1);
    expect(ctx.body.tools?.[0]?.function.name).toBe(`s1${TOOL_NAME_SEPARATOR}a`);
  });

  // Regression: per-agent maxIterations override + clamp.
  // Found by /gstack-review on 2026-04-25.
  // Without the clamp, a hostile agent definition with `extras.maxIterations:1000000`
  // could spin the loop into a near-infinite tool-call burn.
  it('per-agent extras.maxIterations clamps below default and refuses absurd values', async () => {
    const chatRepo = mockChatRepo();
    const tools = mockTools({
      listTools: vi.fn(async () => [{
        name: `g${TOOL_NAME_SEPARATOR}t`, description: '', parameters: {},
      }]),
      callTool: vi.fn(async () => ({})),
    });
    // Agent with maxIterations=2 — only 2 tool-call rounds allowed before bail.
    const agentsLowCap = {
      getByName: vi.fn(async () => ({
        id: 'agent-low', name: 'low', description: '', systemPrompt: '',
        llm: { id: 'llm-1', name: 'qwen3-thinking' },
        project: { id: 'proj-1', name: 'mcpctl-dev' },
        proxyModelName: null, defaultParams: {},
        extras: { maxIterations: 2 },
        ownerId: 'owner-1', version: 1, createdAt: NOW, updatedAt: NOW,
      })),
    } as unknown as AgentService;
    const adapter = scriptedAdapter([toolCall(`g${TOOL_NAME_SEPARATOR}t`, {})]);
    const svc = new ChatService(
      agentsLowCap, mockLlms(), adapterRegistry(adapter),
      chatRepo, mockPromptRepo(), tools,
    );
    await expect(svc.chat({
      agentName: 'low', userMessage: 'spin', ownerId: 'owner-1',
    })).rejects.toThrow(/exceeded 2 iterations/);

    // Hostile agent with maxIterations=1000000 — must clamp to 50, not iterate forever.
    const agentsHostile = {
      getByName: vi.fn(async () => ({
        id: 'agent-bad', name: 'bad', description: '', systemPrompt: '',
        llm: { id: 'llm-1', name: 'qwen3-thinking' },
        project: { id: 'proj-1', name: 'mcpctl-dev' },
        proxyModelName: null, defaultParams: {},
        extras: { maxIterations: 1_000_000 },
        ownerId: 'owner-1', version: 1, createdAt: NOW, updatedAt: NOW,
      })),
    } as unknown as AgentService;
    const adapter2 = scriptedAdapter([toolCall(`g${TOOL_NAME_SEPARATOR}t`, {})]);
    const chatRepo2 = mockChatRepo();
    const svc2 = new ChatService(
      agentsHostile, mockLlms(), adapterRegistry(adapter2),
      chatRepo2, mockPromptRepo(), tools,
    );
    await expect(svc2.chat({
      agentName: 'bad', userMessage: 'spin', ownerId: 'owner-1',
    })).rejects.toThrow(/exceeded 50 iterations/);
  });

  // Regression: thread message reads must enforce ownership.
  // Found by /gstack-review on 2026-04-25.
  // Without this, any caller with `view:agents` could read another user's thread
  // by guessing/learning the threadId (CUIDs leak through SSE chunks + tool _meta).
  it('listMessages refuses a thread owned by another user (404, not 403, to avoid id-enumeration)', async () => {
    const chatRepo = mockChatRepo();
    // Pre-seed a thread owned by 'alice'
    await chatRepo.createThread({ agentId: 'agent-x', ownerId: 'alice' });
    const aliceThread = chatRepo._threads[0]!;
    await chatRepo.appendMessage({
      threadId: aliceThread.id,
      role: 'user',
      content: 'private to alice',
    });

    const svc = new ChatService(
      mockAgents(), mockLlms(), adapterRegistry(scriptedAdapter([chatCompletion('ok')])),
      chatRepo, mockPromptRepo(), mockTools(),
    );

    // Bob requests Alice's thread by id — must 404.
    await expect(svc.listMessages(aliceThread.id, 'bob'))
      .rejects.toThrow(/not found/i);

    // Alice gets her own messages.
    const aliceMessages = await svc.listMessages(aliceThread.id, 'alice');
    expect(aliceMessages.map((m) => m.content)).toEqual(['private to alice']);

    // Genuinely missing thread — same 404 shape (no oracle leak).
    await expect(svc.listMessages('cnonexistent000000000000000', 'alice'))
      .rejects.toThrow(/not found/i);
  });
});