import { accessSync, constants } from 'node:fs';
import path from 'node:path';
import type { AgentBrowserModule } from '../agent-browser';
import { CodingAttachmentStore } from '../coding-projects/attachment-store';
import { createCodingConversationStore } from '../coding-projects/conversation-store';
import { CodingProjectService } from '../coding-projects/project-service';
import {
  createCodingProjectStore,
  type CodingProjectStore,
  type CodingProjectStorage,
} from '../coding-projects/project-store';
import { CodingConversationService } from '../coding-runtime/conversation-service';
import { PiManagedExtensionHost } from '../coding-runtime/pi/extension-host';
import { PiAgentServerProcess } from '../coding-runtime/pi/agent-server-process';
import { PiManagedInputRevisionCoordinator } from '../coding-runtime/pi/managed-input-revision';
import { PiProductTools } from '../coding-runtime/pi/product-tools';
import {
  buildPiProviderCatalog,
  resolvePiProviderCredentialFromSecretStore,
  selectPiProviderModel,
} from '../coding-runtime/pi/provider-config';
import {
  createPiManagedWorkerOpener,
  PiConversationRuntime,
} from '../coding-runtime/pi/runtime';
import { PiSessionRegistry } from '../coding-runtime/pi/session-registry';
import { createPiManagedSubagentChildOpener } from '../coding-runtime/pi/subagent-child';
import { PiSubagentScheduler } from '../coding-runtime/pi/subagent';
import { PiProcessBudget, PiWorkerPool } from '../coding-runtime/pi/worker-pool';
import { getProviderService } from '../services/providers/provider-service';
import {
  isCodingProviderAuthenticationError,
  refreshCodingProviderCredential,
} from './coding-provider-auth';
import { createCodingProductHost, type CodingProductComposition } from './coding-product-services';
import {
  archivePiConversationSession,
  getPiManagedPaths,
} from '../coding-runtime/pi/resource-loader';

export interface CodingCompositionPaths {
  executablePath: string;
  cliPath: string;
  serverPath: string;
  userDataDir: string;
  bundledSkillsDir: string;
}

export interface CreateCodingCompositionOptions {
  storage: CodingProjectStorage;
  projectStore?: CodingProjectStore;
  browser: AgentBrowserModule;
  paths: CodingCompositionPaths;
  getLocalProxyCredential?(): string | undefined;
  acquireBackgroundLease?(lease: { id: string; kind: 'coding-run' }): () => void;
}

type PiWorkerExecutableProbe = (candidate: string) => boolean;

function canExecute(candidate: string): boolean {
  try {
    accessSync(candidate, constants.X_OK);
    return true;
  } catch {
    return false;
  }
}

export function resolvePiWorkerExecutablePath(
  executablePath: string,
  options: {
    platform?: NodeJS.Platform;
    canExecute?: PiWorkerExecutableProbe;
  } = {},
): string {
  if ((options.platform ?? process.platform) !== 'darwin') return executablePath;

  // The product binary remains a Foreground LaunchServices app even in Node mode.
  // Electron's generic Helper is LSUIElement=true, so workers stay out of the Dock.
  const executableName = path.basename(executablePath);
  const helperExecutablePath = path.resolve(
    path.dirname(executablePath),
    '..',
    'Frameworks',
    `${executableName} Helper.app`,
    'Contents',
    'MacOS',
    `${executableName} Helper`,
  );
  return (options.canExecute ?? canExecute)(helperExecutablePath)
    ? helperExecutablePath
    : executablePath;
}

export function resolveCodingPiRuntimePaths(input: {
  isPackaged: boolean;
  resourcesPath: string;
  appPath: string;
  executablePath: string;
}): Pick<CodingCompositionPaths, 'executablePath' | 'cliPath' | 'serverPath'> {
  return {
    executablePath: resolvePiWorkerExecutablePath(input.executablePath),
    cliPath: input.isPackaged
      ? path.join(input.resourcesPath, 'pi-runtime', 'dist', 'cli.js')
      : path.join(
          input.appPath,
          'node_modules',
          '@earendil-works',
          'pi-coding-agent',
          'dist',
          'cli.js',
        ),
    serverPath: input.isPackaged
      ? path.join(input.resourcesPath, 'resources', 'pi-agent-server.mjs')
      : path.join(input.appPath, 'resources', 'pi-agent-server.mjs'),
  };
}

export function createCodingComposition(
  options: CreateCodingCompositionOptions,
): CodingProductComposition {
  const getLocalProxyCredential = options.getLocalProxyCredential;
  const projectStore = options.projectStore ?? createCodingProjectStore(options.storage);
  const attachments = new CodingAttachmentStore(
    path.join(options.paths.userDataDir, 'coding-runtime', 'attachments'),
  );
  const productTools = new PiProductTools({
    browser: options.browser,
    attachments,
    bundledSkillsDir: options.paths.bundledSkillsDir,
  });
  const extensionHost = new PiManagedExtensionHost();
  extensionHost.configureProductTools(productTools);
  const conversationStores = new Map<string, ReturnType<typeof createCodingConversationStore>>();
  const conversationStoreForProject = (projectPath: string) => {
    const existing = conversationStores.get(projectPath);
    if (existing) return existing;
    const created = createCodingConversationStore(projectPath);
    conversationStores.set(projectPath, created);
    return created;
  };
  const registry = new PiSessionRegistry({
    projectStore,
    createConversationStore: conversationStoreForProject,
  });
  const revisions = new PiManagedInputRevisionCoordinator();
  const processBudget = new PiProcessBudget();
  const agentServer = new PiAgentServerProcess({
    executablePath: options.paths.executablePath,
    serverPath: options.paths.serverPath,
    runtimeRoot: path.dirname(path.dirname(options.paths.cliPath)),
    configDir: getPiManagedPaths(options.paths.userDataDir).configDir,
  });
  const loadProviderInput = async () => ({
    accounts: await getProviderService().listAccounts(),
    modelSummaries: [],
  });
  const workerPool = new PiWorkerPool({
    processBudget,
    processMode: 'shared',
    maxIdle: 8,
    revisionCoordinator: revisions,
    openWorker: createPiManagedWorkerOpener({
      registry,
      executablePath: options.paths.executablePath,
      cliPath: options.paths.cliPath,
      userDataDir: options.paths.userDataDir,
      bundledSkillsDir: options.paths.bundledSkillsDir,
      loadProviderInput,
      resolveCredential: resolvePiProviderCredentialFromSecretStore,
      createProcess: (processOptions) => agentServer.createWorker(processOptions),
      ...(getLocalProxyCredential
        ? { getLocalProxyCredential: async () => getLocalProxyCredential() }
        : {}),
      extensionHost,
    }),
  });
  const childOpener = createPiManagedSubagentChildOpener({
    projectStore,
    executablePath: options.paths.executablePath,
    cliPath: options.paths.cliPath,
    userDataDir: options.paths.userDataDir,
    bundledSkillsDir: options.paths.bundledSkillsDir,
    extensionHost,
    loadProviderInput,
    resolveCredential: resolvePiProviderCredentialFromSecretStore,
    getRevision: () => revisions.current,
    ...(getLocalProxyCredential
      ? { getLocalProxyCredential: async () => getLocalProxyCredential() }
      : {}),
  });
  const subagents = new PiSubagentScheduler({
    openChild: childOpener,
    processBudget,
  });
  const runtime = new PiConversationRuntime({
    pool: workerPool,
    registry,
    extensionHost,
    subagentScheduler: subagents,
    resolveModel: async (model) => selectPiProviderModel(
      buildPiProviderCatalog(await loadProviderInput()),
      model,
    ),
    isAuthenticationError: isCodingProviderAuthenticationError,
    refreshCredential: refreshCodingProviderCredential,
    resolveImages: async (refs) => await Promise.all(refs.map(async ({ attachmentId }) => {
      const record = await attachments.read(attachmentId);
      return {
        type: 'image',
        data: record.data.toString('base64'),
        mimeType: record.mime,
      };
    })),
    ...(options.acquireBackgroundLease
      ? { acquireBackgroundLease: options.acquireBackgroundLease }
      : {}),
  });
  const projects = new CodingProjectService(projectStore, {
    createConversationStore: conversationStoreForProject,
    onResourcesChanged: async (project) => {
      runtime.markResourcesStale();
      const conversations = await conversationStoreForProject(project.path).read()
        .then((file) => file.conversations)
        .catch(() => []);
      for (const conversation of conversations) registry.forget(conversation.id);
    },
    onProjectDeactivated: async (project, reason) => {
      const conversations = await conversationStoreForProject(project.path).read()
        .then((file) => file.conversations)
        .catch(() => []);
      await Promise.allSettled([
        options.browser.close(project.path),
        ...conversations.map(({ id }) => runtime.dispose(id, reason)),
      ]);
    },
  });
  const conversations = new CodingConversationService(projects, runtime, {
    archiveSession: async ({ projectId, sessionKey }) => {
      await archivePiConversationSession({
        userDataDir: options.paths.userDataDir,
        projectId,
        sessionKey,
      });
    },
  });
  const host = createCodingProductHost({
    projects,
    productTools,
    listPiCommands: (conversationId) => conversations.listLiveCommands(conversationId),
  });
  return {
    attachments,
    productTools,
    projects,
    conversations,
    runtime,
    host,
    async sleep(reason) {
      if (reason === 'background_sleep' && runtime.hasActiveWork()) return;
      const conversationIds = runtime.getDiagnostics().workers.map((worker) => worker.conversationId);
      await Promise.allSettled(conversationIds.map((conversationId) => (
        runtime.dispose(conversationId, reason)
      )));
      await agentServer.stop();
    },
    async shutdown() {
      await subagents.close();
      try {
        await runtime.shutdown();
      } finally {
        await agentServer.stop();
      }
    },
  };
}