// @vitest-environment node

import { mkdtemp, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import path from 'node:path';
import { afterEach, describe, expect, it } from 'vitest';
import { createCodingConversationStore } from '../../electron/coding-projects/conversation-store';
import { createCodingProjectAgent } from '../../electron/coding-projects/project-config';
import {
  createCodingProjectStore,
  createLocalCodingProject,
  createMemoryCodingProjectStorage,
} from '../../electron/coding-projects/project-store';
import { PiConversationRuntime } from '../../electron/coding-runtime/pi/runtime';
import { PiSessionProjectionError } from '../../electron/coding-runtime/pi/session-projector';
import { PiSessionRegistry } from '../../electron/coding-runtime/pi/session-registry';
import {
  PiWorkerPool,
  type PiConversationWorker,
} from '../../electron/coding-runtime/pi/worker-pool';
import type { PiProcessError } from '../../electron/coding-runtime/pi/process-errors';
import type {
  PiRpcCommand,
  PiRpcEvent,
  PiRpcRequestOptions,
  PiRpcResponse,
} from '../../electron/coding-runtime/pi/rpc-client';
import { PI_084_TEXT_TURN } from '../fixtures/pi-0.84.2-projector-fixtures';

const roots: string[] = [];
const NOW = '2026-08-22T15:00:00.000Z';

class RuntimeFakeWorker implements PiConversationWorker {
  readonly requests: PiRpcCommand[] = [];
  private stateData: unknown;
  private entriesData: unknown = { entries: [], leafId: null };
  private statsData: unknown = {
    contextUsage: { tokens: 0, contextWindow: 100_000, percent: 0 },
    tokens: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
  };
  private failType: string | null = null;
  private readonly responseGates = new Map<string, Promise<void>>();
  private readonly events = new Set<(event: PiRpcEvent) => void>();
  private readonly invalidations = new Set<(error: PiProcessError) => void>();

  constructor(readonly id: string, readonly generation: number) {
    this.stateData = {
      sessionId: `session-${id}`,
      thinkingLevel: 'medium',
      isStreaming: false,
      isCompacting: false,
      pendingMessageCount: 0,
    };
  }

  async request<T = unknown>(
    command: PiRpcCommand,
    _options?: PiRpcRequestOptions,
  ): Promise<PiRpcResponse<T>> {
    this.requests.push(structuredClone(command));
    await this.responseGates.get(command.type);
    this.responseGates.delete(command.type);
    if (command.type === this.failType) {
      this.failType = null;
      throw new Error(`fake ${command.type} rejection`);
    }
    const data = command.type === 'get_state'
      ? this.stateData
      : command.type === 'get_entries'
        ? this.entriesData
        : command.type === 'get_session_stats' ? this.statsData : undefined;
    return {
      type: 'response',
      id: `${this.id}-${this.requests.length}`,
      success: true,
      ...(data === undefined ? {} : { data: structuredClone(data) as T }),
    };
  }

  setSessionData(input: { state?: unknown; entries?: unknown; stats?: unknown }): void {
    if (input.state !== undefined) this.stateData = structuredClone(input.state);
    if (input.entries !== undefined) this.entriesData = structuredClone(input.entries);
    if (input.stats !== undefined) this.statsData = structuredClone(input.stats);
  }

  failNext(type: string): void { this.failType = type; }

  holdNext(type: string): () => void {
    let release!: () => void;
    this.responseGates.set(type, new Promise<void>((resolve) => { release = resolve; }));
    return release;
  }

  subscribe(listener: (event: PiRpcEvent) => void): () => void {
    this.events.add(listener);
    return () => this.events.delete(listener);
  }

  subscribeInvalidation(listener: (error: PiProcessError) => void): () => void {
    this.invalidations.add(listener);
    return () => this.invalidations.delete(listener);
  }

  emit(event: PiRpcEvent): void {
    for (const listener of this.events) listener(event);
  }

  async stop() {
    return { mode: 'stdin-close' as const, code: 0, signal: null };
  }
}

afterEach(async () => {
  await Promise.all(roots.splice(0).map((root) => rm(root, { recursive: true, force: true })));
});

describe('Pi Conversation runtime', () => {
  it('separates RPC acceptance from settle and changes only the target Conversation model', async () => {
    const projectPath = await mkdtemp(path.join(tmpdir(), 'makelore-pi-runtime-'));
    roots.push(projectPath);
    const projectStore = createCodingProjectStore(createMemoryCodingProjectStorage(), {
      createId: () => 'project-a',
      now: () => NOW,
    });
    await createLocalCodingProject({ projectPath, now: NOW }, projectStore);
    await createCodingProjectAgent(projectPath, {
      id: 'agent-a',
      avatarId: 'avatar-01',
      roleName: 'Implementer',
      name: 'Agent A',
      model: { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' },
      modelResolution: 'resolved',
      responsibility: { mission: 'Implement', owns: [], boundaries: [], collaborators: [], principles: [] },
    }, { now: NOW });
    const store = createCodingConversationStore(projectPath, {
      createId: (() => {
        const ids = [
          'f47ac10b-58cc-4372-a567-0e02b2c3d479',
          '8b1a9953-c461-4d88-9c3e-7e1f8f3f2c11',
          '3d594650-3436-4a8c-8b38-7d1c5e3f9a20',
        ];
        return () => ids.shift() as string;
      })(),
      now: () => NOW,
    });
    const model = { accountId: 'account-a', modelId: 'model-a', thinkingLevel: 'medium' as const };
    const left = await store.create({ agentId: 'agent-a', title: 'Left', model, modelResolution: 'resolved' });
    const right = await store.create({ agentId: 'agent-a', title: 'Right', model, modelResolution: 'resolved' });
    const forkTarget = await store.create({ agentId: 'agent-a', title: 'Fork', model, modelResolution: 'resolved' });
    const inputs = [left, right, forkTarget].map((item) => ({
      conversationId: item.id,
      projectId: 'project-a',
      agentId: 'agent-a',
      title: item.title,
      model: { model: item.model, modelResolution: item.modelResolution },
    }));
    const workers = new Map<string, RuntimeFakeWorker>();
    const workerHistory = new Map<string, RuntimeFakeWorker[]>();
    const durableSessions = new Map<string, Parameters<RuntimeFakeWorker['setSessionData']>[0]>();
    const openInputs: Array<{ conversationId: string; forkSource?: string; sourceEntryId?: string }> = [];
    const pool = new PiWorkerPool({
      maxIdle: 4,
      openWorker: async ({ conversation, fork, generation, existingSession }) => {
        openInputs.push({
          conversationId: conversation.conversationId,
          ...(fork ? {
            forkSource: fork.sourceSession.piSessionId,
            sourceEntryId: fork.sourceEntryId,
          } : {}),
        });
        const worker = new RuntimeFakeWorker(`worker-${conversation.conversationId}-${generation}`, generation);
        const durable = durableSessions.get(conversation.conversationId);
        if (durable) worker.setSessionData(durable);
        workers.set(conversation.conversationId, worker);
        workerHistory.set(conversation.conversationId, [
          ...(workerHistory.get(conversation.conversationId) ?? []),
          worker,
        ]);
        return {
          worker,
          session: existingSession ?? {
            piSessionId: `session-${conversation.conversationId}`,
            sessionKey: `key-${conversation.conversationId}`,
          },
        };
      },
    });
    const runtime = new PiConversationRuntime({
      pool,
      registry: new PiSessionRegistry({ projectStore }),
      createId: (kind) => `${kind}-fixed`,
      resolveModel: async (candidate) => {
        if (candidate.accountId !== 'account-b' || candidate.modelId !== 'model-b') {
          throw new Error('model unavailable');
        }
        return {
          accountId: candidate.accountId,
          runtimeProviderId: 'runtime-account-b',
          modelId: candidate.modelId,
          thinkingLevel: candidate.thinkingLevel,
          input: ['text'],
        };
      },
    });
    await Promise.all(inputs.slice(0, 2).map((input) => runtime.prepare(input)));

    const releasePromptAcceptance = workers.get(left.id)!.holdNext('prompt');
    let acceptanceResolved = false;
    const acceptance = runtime.prompt({
      clientRequestId: 'request-left',
      conversationId: left.id,
      mode: 'prompt',
      text: 'Implement the change',
      attachments: [],
    }).then((value) => {
      acceptanceResolved = true;
      return value;
    });
    await expect.poll(() => workers.get(left.id)!.requests.at(-1)?.type).toBe('prompt');
    expect(workers.get(left.id)!.requests).toHaveLength(4);
    expect(acceptanceResolved).toBe(false);
    releasePromptAcceptance();
    const accepted = await acceptance;
    expect(accepted).toMatchObject({ accepted: true, runId: 'run-fixed', mode: 'prompt' });
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('running');
    for (const event of PI_084_TEXT_TURN.events) {
      workers.get(left.id)!.emit(structuredClone(event));
    }
    const streamed = await runtime.getSnapshot(left.id);
    expect(streamed.nodes).toContainEqual(expect.objectContaining({
      kind: 'message',
      id: 'client:request-left',
      clientRequestId: 'request-left',
      status: 'complete',
    }));
    expect(JSON.stringify(streamed.nodes)).toContain('Implemented');
    const durable = {
      state: {
        sessionId: `session-${left.id}`,
        thinkingLevel: 'medium',
        isStreaming: false,
        isCompacting: false,
        pendingMessageCount: 0,
      },
      entries: PI_084_TEXT_TURN.entries,
      stats: PI_084_TEXT_TURN.stats,
    };
    durableSessions.set(left.id, durable);
    workers.get(left.id)!.setSessionData(durable);
    workers.get(left.id)!.emit({ type: 'agent_end' });
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('running');
    const checkpoint = await runtime.getSnapshot(left.id);
    expect(checkpoint.cursor.leafEntryId).toBe('entry-assistant-a');
    expect(checkpoint.nodes).toContainEqual(expect.objectContaining({
      kind: 'message',
      id: 'client:request-left',
      sourceEntryId: 'entry-user-a',
    }));
    const releaseSettledHydration = workers.get(left.id)!.holdNext('get_entries');
    workers.get(left.id)!.emit({ type: 'agent_settled' });
    let continuationAccepted = false;
    const continuation = runtime.followUp({
      clientRequestId: 'request-after-settled',
      conversationId: left.id,
      text: 'Continue only after the checkpoint',
      attachments: [],
    }).then((result) => {
      continuationAccepted = true;
      return result;
    });
    await expect.poll(() => workers.get(left.id)!.requests.filter(
      ({ type }) => type === 'get_entries',
    ).length).toBe(3);
    expect(workers.get(left.id)!.requests.some(({ type }) => type === 'follow_up')).toBe(false);
    expect(continuationAccepted).toBe(false);
    releaseSettledHydration();
    await expect(continuation).resolves.toMatchObject({ mode: 'follow-up', queuePosition: 1 });
    workers.get(left.id)!.emit({ type: 'agent_settled' });
    await expect.poll(async () => (await runtime.getSnapshot(left.id)).queue.items).toEqual([]);
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('idle');
    const settledNodes = (await runtime.getSnapshot(left.id)).nodes;
    expect(settledNodes).toEqual(checkpoint.nodes);

    const changed = await runtime.setModel({
      conversationId: left.id,
      accountId: 'account-b',
      modelId: 'model-b',
    });
    expect(changed.model).toEqual({ accountId: 'account-b', modelId: 'model-b', thinkingLevel: 'medium' });
    expect(workerHistory.get(left.id)).toHaveLength(2);
    expect(workerHistory.get(left.id)![0]!.requests).not.toContainEqual(expect.objectContaining({
      type: 'set_model',
    }));
    expect(workers.get(left.id)!.requests.map(({ type }) => type).sort()).toEqual([
      'get_entries',
      'get_session_stats',
      'get_state',
    ]);
    expect(pool.getState(left.id)).toMatchObject({ generation: 2, state: 'ready' });
    expect(pool.getState(right.id)).toMatchObject({ generation: 1, state: 'ready' });
    expect((await runtime.getSnapshot(right.id)).conversation.model.model).toEqual(model);
    expect((await runtime.getSnapshot(left.id)).nodes).toEqual(settledNodes);

    await expect(runtime.setModel({
      conversationId: left.id,
      accountId: 'account-missing',
      modelId: 'model-missing',
    })).rejects.toThrow('model unavailable');
    expect((await runtime.getSnapshot(left.id)).conversation.model).toEqual(changed);

    await runtime.prompt({
      clientRequestId: 'request-left-active',
      conversationId: left.id,
      mode: 'prompt',
      text: 'Keep working',
      attachments: [],
    });
    await expect.poll(async () => (await runtime.getSnapshot(left.id)).run.status).toBe('running');
    workers.get(left.id)!.failNext('steer');
    await expect(runtime.steer({
      clientRequestId: 'request-left-rejected-steer',
      conversationId: left.id,
      text: 'This command is rejected',
      attachments: [],
    })).rejects.toThrow('fake steer rejection');
    expect((await runtime.getSnapshot(left.id)).queue.items).toEqual([]);
    await expect(runtime.steer({
      clientRequestId: 'request-left-steer',
      conversationId: left.id,
      text: 'Use the smaller seam',
      attachments: [],
    })).resolves.toMatchObject({ accepted: true, mode: 'steer', queuePosition: 1 });
    await expect(runtime.followUp({
      clientRequestId: 'request-left-follow-up',
      conversationId: left.id,
      text: 'Then run the focused test',
      attachments: [],
    })).resolves.toMatchObject({ accepted: true, mode: 'follow-up', queuePosition: 2 });
    await expect(runtime.setThinking({
      conversationId: left.id,
      thinkingLevel: 'high',
    })).resolves.toMatchObject({
      model: { accountId: 'account-b', modelId: 'model-b', thinkingLevel: 'high' },
    });
    workers.get(left.id)!.failNext('abort');
    await expect(runtime.abort(left.id)).rejects.toThrow('fake abort rejection');
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('running');
    await runtime.abort(left.id);
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('aborting');
    expect(workers.get(left.id)!.requests.slice(-6).map(({ type }) => type)).toEqual([
      'steer',
      'steer',
      'follow_up',
      'set_thinking_level',
      'abort',
      'abort',
    ]);
    expect(workers.get(right.id)!.requests.map(({ type }) => type)).toEqual([
      'get_state',
      'get_entries',
      'get_session_stats',
    ]);
    workers.get(left.id)!.emit({ type: 'agent_settled' });
    await expect.poll(async () => (await runtime.getSnapshot(left.id)).run.status).toBe('idle');
    expect((await runtime.getSnapshot(left.id)).queue.items).toEqual([]);

    workers.get(right.id)!.failNext('compact');
    await expect(runtime.compact(right.id)).rejects.toThrow('fake compact rejection');
    expect((await runtime.getSnapshot(right.id)).run.status).toBe('error');
    await runtime.compact(right.id);
    expect((await runtime.getSnapshot(right.id)).run.status).toBe('compacting');
    expect(workers.get(right.id)!.requests.at(-1)).toEqual({ type: 'compact' });
    expect((await runtime.getSnapshot(left.id)).run.status).toBe('idle');
    const rightDurable = {
      entries: {
        leafId: 'entry-right-user',
        entries: [{
          type: 'message',
          id: 'entry-right-user',
          parentId: null,
          timestamp: NOW,
          message: { role: 'user', content: 'Right history', timestamp: 1 },
        }],
      },
    };
    durableSessions.set(right.id, rightDurable);
    workers.get(right.id)!.setSessionData(rightDurable);
    workers.get(right.id)!.emit({ type: 'agent_end' });
    expect((await runtime.getSnapshot(right.id)).run.status).toBe('compacting');
    workers.get(right.id)!.emit({ type: 'agent_settled' });
    await expect.poll(async () => (await runtime.getSnapshot(right.id)).run.status).toBe('idle');

    const leftBeforeFailedRecovery = await runtime.getSnapshot(left.id);
    const rightBeforeFailedRecovery = await runtime.getSnapshot(right.id);
    const corruptRightSession = {
      entries: {
        leafId: 'entry-corrupt',
        entries: [{
          type: 'message',
          id: 'entry-corrupt',
          parentId: 'missing-parent',
          timestamp: NOW,
          message: { role: 'user', content: 'must not replace history', timestamp: 1 },
        }],
      },
    };
    durableSessions.set(right.id, corruptRightSession);
    await expect(runtime.recover(right.id)).rejects.toBeInstanceOf(PiSessionProjectionError);
    expect((await runtime.getSnapshot(right.id)).nodes).toEqual(rightBeforeFailedRecovery.nodes);
    expect((await runtime.getSnapshot(right.id)).worker).toMatchObject({
      status: 'error',
      generation: 2,
      error: { code: 'CODING_SESSION_UNREADABLE', recoverable: true },
    });
    expect(await runtime.getSnapshot(left.id)).toEqual(leftBeforeFailedRecovery);

    durableSessions.set(right.id, rightDurable);
    await expect(runtime.recover(right.id)).resolves.toMatchObject({
      conversationId: right.id,
      status: 'ready',
      workerGeneration: 3,
    });
    expect((await runtime.getSnapshot(right.id)).cursor).toMatchObject({
      workerGeneration: 3,
      seq: 0,
    });
    expect(workers.get(right.id)!.requests.map(({ type }) => type).sort()).toEqual([
      'get_entries',
      'get_session_stats',
      'get_state',
    ]);
    expect(pool.getState(left.id)).toMatchObject({ generation: 2, state: 'idle' });

    const sourceRequestCount = workers.get(left.id)!.requests.length;
    const forked = await runtime.fork({
      sourceConversationId: left.id,
      sourceEntryId: 'entry-a',
      conversation: inputs[2]!,
    });
    expect(forked.conversationId).toBe(forkTarget.id);
    expect(workers.get(forkTarget.id)?.id).toBe(`worker-${forkTarget.id}-1`);
    expect(workers.get(left.id)!.requests).toHaveLength(sourceRequestCount);
    expect(openInputs.at(-1)).toEqual({
      conversationId: forkTarget.id,
      forkSource: `session-${left.id}`,
      sourceEntryId: 'entry-a',
    });

    await runtime.dispose(forkTarget.id);
    expect(pool.getState(forkTarget.id)).toBeNull();
    expect(pool.getState(left.id)).toMatchObject({ generation: 2, state: 'idle' });
    await expect(runtime.getSnapshot(forkTarget.id)).rejects.toMatchObject({
      publicError: { code: 'CODING_CONVERSATION_NOT_FOUND' },
    });
  });
});