import type { FastifyInstance, FastifyReply, FastifyRequest } from 'fastify';
import type { Instance } from '@multi-simadmin/contracts';
import type { InstanceService } from '../../application/instances/instance-service.js';
import type { InstanceResourceService } from '../../application/resources/instance-resource-service.js';
import type {
  ConnectionState,
  ConnectionProbe,
} from '../../application/connections/connection-probe.js';
import {
  MessageServiceError,
  type DeleteSmsMessageRequest,
} from '../../application/messages/instance-message-service.js';
import type { HubMessageService } from '../../application/messages/hub-message-service.js';
import {
  type SmsOutboxItem,
  type SmsOutboxService,
  type SmsOutboxStatus,
} from '../../application/messages/sms-outbox-service.js';
import {
  NotificationServiceError,
  type InstanceNotificationService,
} from '../../application/notifications/instance-notification-service.js';
import type {
  DeviceIdentity,
  DeviceIdentityService,
  IdentityReason,
} from '../../application/identity/device-identity-service.js';
export interface FleetMessageDevice {
  readonly id: string;
  readonly name: string;
  readonly availability: 'online' | 'unavailable';
}

export interface FleetMessage {
  readonly id: string;
  readonly instanceId: string;
  readonly instanceName: string;
  readonly direction: string;
  readonly phoneNumber: string;
  readonly content: string;
  readonly timestamp: string;
  readonly status: string;
  readonly transport: string;
}

export interface FleetMessagesResponse {
  readonly messages: readonly FleetMessage[];
  readonly devices: readonly FleetMessageDevice[];
  readonly total: number;
}

export interface FleetMessageConversation {
  readonly instanceId: string;
  readonly instanceName: string;
  readonly phoneNumber: string;
  readonly messageCount: number;
  readonly incomingCount: number;
  readonly lastMessage: FleetMessage;
}

export interface FleetMessageConversationsResponse {
  readonly conversations: readonly FleetMessageConversation[];
  readonly total: number;
  readonly stats: { readonly incoming: number; readonly outgoing: number; readonly total: number };
}

export interface FleetRoutesOptions {
  readonly instances: InstanceService;
  readonly resources: InstanceResourceService;
  readonly messages: HubMessageService;
  readonly notifications: InstanceNotificationService;
  /** Reads the heartbeat journal; the overview never probes live so the page stays cheap. */
  readonly connections?: ConnectionProbe;
  /** Offline send queue; absent means sends fail fast instead of waiting for the device. */
  readonly outbox?: SmsOutboxService;
  /** Identity guard; absent means the fleet list has no opinion about hardware drift. */
  readonly identities?: DeviceIdentityService;
}

export interface FleetIdentitySummary {
  readonly tracked: boolean;
  readonly status: 'confirmed' | 'pending';
  readonly reasons: readonly IdentityReason[];
}

/** One queued send, with the node label the queue table itself does not store. */
export type FleetOutboxItem = SmsOutboxItem & { readonly instanceName: string };

function parseOutboxQuery(query: unknown): {
  readonly status: SmsOutboxStatus | 'open' | 'all';
  readonly instanceId?: string;
  readonly limit: number;
  readonly offset: number;
} {
  const value = record(query) ?? {};
  if (Object.keys(value).some((key) => !['status', 'instanceId', 'limit', 'offset'].includes(key)))
    throw new MessageServiceError('VALIDATION_FAILED');
  const status = value.status;
  if (status !== undefined && typeof status !== 'string')
    throw new MessageServiceError('VALIDATION_FAILED');
  const resolved = (status ?? 'open') as SmsOutboxStatus | 'open' | 'all';
  if (!OUTBOX_STATUSES.includes(resolved)) throw new MessageServiceError('VALIDATION_FAILED');
  const instanceId = value.instanceId;
  if (
    instanceId !== undefined &&
    (typeof instanceId !== 'string' || instanceId.length > 256 || instanceId.trim() === '')
  )
    throw new MessageServiceError('VALIDATION_FAILED');
  const integer = (key: 'limit' | 'offset', fallback: number, maximum: number): number => {
    const raw = value[key];
    if (raw === undefined) return fallback;
    if (typeof raw !== 'string' || !/^\d+$/u.test(raw))
      throw new MessageServiceError('VALIDATION_FAILED');
    const parsed = Number(raw);
    if (!Number.isSafeInteger(parsed) || parsed < 0 || parsed > maximum)
      throw new MessageServiceError('VALIDATION_FAILED');
    return parsed;
  };
  return {
    status: resolved,
    ...(typeof instanceId === 'string' && instanceId.trim() !== ''
      ? { instanceId: instanceId.trim() }
      : {}),
    limit: integer('limit', 25, MAX_FLEET_OUTBOX_LIMIT),
    offset: integer('offset', 0, MAX_FLEET_MESSAGE_OFFSET),
  };
}

function outboxQueueId(value: unknown): string {
  const id = typeof value === 'string' ? value : '';
  if (!/^[A-Za-z0-9_.-]{1,64}$/u.test(id)) throw new MessageServiceError('VALIDATION_FAILED');
  return id;
}

const OUTBOX_STATUSES: readonly (SmsOutboxStatus | 'open' | 'all')[] = [
  'open',
  'all',
  'queued',
  'sending',
  'sent',
  'failed',
  'cancelled',
];

/**
 * Heartbeat view of one device. `probed: false` means the control plane has never reached it,
 * which the fleet table shows as 未知 rather than a misleading 离线.
 */
export interface FleetConnectionSummary {
  readonly probed: boolean;
  readonly reachable: boolean;
  readonly authenticated: boolean;
  readonly checkedAt: string | null;
}

const PAGE_SIZE = 100;
const MAX_FLEET_DEVICES = 200;
const MAX_FLEET_MESSAGE_LIMIT = 100;
const MAX_FLEET_CONVERSATION_LIMIT = 200;
const MAX_FLEET_MESSAGE_OFFSET = 1000;
const MAX_FLEET_OUTBOX_LIMIT = 100;
const EMPTY_OUTBOX_SUMMARY = Object.freeze({ queued: 0, sending: 0, failed: 0, sent: 0 });

interface QueryMessagesInput {
  readonly limit: number;
  readonly offset: number;
  readonly search?: string;

  readonly instanceId?: string;
  readonly phoneNumber?: string;
}

/** Thread-level direction filter, accepted only by the conversation endpoint. */
export interface QueryConversationsInput extends QueryMessagesInput {
  readonly direction?: 'incoming' | 'outgoing';
}

async function listInstances(instances: InstanceService): Promise<readonly Instance[]> {
  const result: Instance[] = [];
  let page = 1;
  while (result.length < MAX_FLEET_DEVICES) {
    const current = await instances.list({ page, pageSize: PAGE_SIZE });
    result.push(...current.items.slice(0, MAX_FLEET_DEVICES - result.length));
    if (current.items.length < PAGE_SIZE) break;
    page += 1;
  }
  return result;
}

function connectionSummary(state: ConnectionState | undefined): FleetConnectionSummary {
  if (!state) return { probed: false, reachable: false, authenticated: false, checkedAt: null };
  return {
    probed: true,
    reachable: state.reachable,
    authenticated: state.authenticated,
    checkedAt: state.checkedAt,
  };
}

function identitySummary(identity: DeviceIdentity | undefined): FleetIdentitySummary {
  if (!identity) return { tracked: false, status: 'confirmed', reasons: [] };
  return { tracked: true, status: identity.status, reasons: identity.reasons };
}

function record(value: unknown): Record<string, unknown> | undefined {
  if (!value || typeof value !== 'object' || Array.isArray(value)) return undefined;
  return value as Record<string, unknown>;
}

function parseMessagesQuery(
  query: unknown,
  maximumLimit = MAX_FLEET_MESSAGE_LIMIT,
  allowDirection = false,
): QueryConversationsInput {
  const value = record(query) ?? {};
  if (
    Object.keys(value).some(
      (key) =>
        !['limit', 'offset', 'search', 'instanceId', 'phoneNumber'].includes(key) &&
        !(allowDirection && key === 'direction'),
    )
  )
    throw new MessageServiceError('VALIDATION_FAILED');
  const integer = (key: 'limit' | 'offset', fallback: number, maximum: number): number => {
    const raw = value[key];
    if (raw === undefined) return fallback;
    if (typeof raw !== 'string' || !/^\d+$/u.test(raw)) {
      throw new MessageServiceError('VALIDATION_FAILED');
    }
    const parsed = Number(raw);
    if (!Number.isSafeInteger(parsed) || parsed < 0 || parsed > maximum)
      throw new MessageServiceError('VALIDATION_FAILED');
    return parsed;
  };
  const search = value.search;
  if (search !== undefined && (typeof search !== 'string' || search.length > 200))
    throw new MessageServiceError('VALIDATION_FAILED');
  const instanceId = value.instanceId;
  if (
    instanceId !== undefined &&
    (typeof instanceId !== 'string' || instanceId.length > 256 || instanceId.trim() === '')
  )
    throw new MessageServiceError('VALIDATION_FAILED');
  const phoneNumber = value.phoneNumber;
  if (
    phoneNumber !== undefined &&
    (typeof phoneNumber !== 'string' || phoneNumber.length > 32 || phoneNumber.trim() === '')
  )
    throw new MessageServiceError('VALIDATION_FAILED');
  const direction = value.direction;
  if (
    direction !== undefined &&
    (!allowDirection || (direction !== 'incoming' && direction !== 'outgoing'))
  )
    throw new MessageServiceError('VALIDATION_FAILED');
  return {
    limit: integer('limit', 24, maximumLimit),
    offset: integer('offset', 0, MAX_FLEET_MESSAGE_OFFSET),
    ...(typeof search === 'string' && search.trim() !== '' ? { search: search.trim() } : {}),
    ...(typeof instanceId === 'string' && instanceId.trim() !== ''
      ? { instanceId: instanceId.trim() }
      : {}),
    ...(typeof phoneNumber === 'string' && phoneNumber.trim() !== ''
      ? { phoneNumber: phoneNumber.trim() }
      : {}),
    ...(direction === 'incoming' || direction === 'outgoing' ? { direction } : {}),
  };
}

function parseMessageDeleteItems(value: unknown): readonly DeleteSmsMessageRequest[] {
  const body = record(value);
  const items = body?.items;
  if (!Array.isArray(items) || items.length < 1 || items.length > 500)
    throw new MessageServiceError('VALIDATION_FAILED');
  return items.map((item) => {
    const current = record(item);
    const instanceId = typeof current?.instanceId === 'string' ? current.instanceId : '';
    const id =
      typeof current?.id === 'string'
        ? current.id
        : typeof current?.id === 'number' && Number.isSafeInteger(current.id) && current.id >= 0
          ? String(current.id)
          : '';
    if (!instanceId || !id) throw new MessageServiceError('VALIDATION_FAILED');
    return { instanceId, id };
  });
}

async function mapWithConcurrency<Item, Result>(
  items: readonly Item[],
  concurrency: number,
  mapper: (item: Item, index: number) => Promise<Result>,
): Promise<readonly Result[]> {
  const results: Result[] = new Array(items.length);
  let next = 0;
  const workers = Array.from({ length: Math.min(concurrency, items.length) }, async () => {
    while (next < items.length) {
      const index = next;
      next += 1;
      results[index] = await mapper(items[index]!, index);
    }
  });
  await Promise.all(workers);
  return results;
}

function wrapMessageAction<T>(
  handler: (request: FastifyRequest) => Promise<T>,
): (request: FastifyRequest, reply: FastifyReply) => Promise<T> {
  return async (request, reply) => {
    try {
      return await handler(request);
    } catch (error) {
      if (error instanceof MessageServiceError) {
        const status =
          error.code === 'NOT_FOUND' ? 404 : error.code === 'VALIDATION_FAILED' ? 400 : 502;
        return reply
          .code(status)
          .type('application/problem+json')
          .send({
            type: 'about:blank',
            title: status === 400 ? 'Bad Request' : status === 404 ? 'Not Found' : 'Bad Gateway',
            status,
            code: error.code,
            detail: 'The requested Fleet message operation could not be completed.',
            requestId: request.id,
          });
      }
      throw error;
    }
  };
}

interface FleetNotificationQueueItemParams {
  readonly instanceId: string;
  readonly queueId: string;
}

function wrapNotificationAction<T>(
  handler: (
    request: FastifyRequest<{ readonly Params: FleetNotificationQueueItemParams }>,
  ) => Promise<T>,
): (request: FastifyRequest, reply: FastifyReply) => Promise<T> {
  return async (request, reply) => {
    try {
      return await handler(
        request as FastifyRequest<{ readonly Params: FleetNotificationQueueItemParams }>,
      );
    } catch (error) {
      if (error instanceof NotificationServiceError) {
        const status =
          error.code === 'NOT_FOUND' ? 404 : error.code === 'VALIDATION_FAILED' ? 400 : 502;
        return reply
          .code(status)
          .type('application/problem+json')
          .send({
            type: 'about:blank',
            title: status === 400 ? 'Bad Request' : status === 404 ? 'Not Found' : 'Bad Gateway',
            status,
            code: error.code,
            detail: 'The requested Fleet notification queue operation could not be completed.',
            requestId: request.id,
          });
      }
      throw error;
    }
  };
}

export function registerFleetRoutes(app: FastifyInstance, options: FleetRoutesOptions): void {
  app.get('/api/v1/fleet/overview', async () => {
    const instances = await listInstances(options.instances);
    const reachability = options.connections?.reachability();
    const items = await mapWithConcurrency(instances, 6, async (instance) => ({
      ...instance,
      connection: connectionSummary(reachability?.get(instance.id)),
      resources: await options.resources.get(instance.id),
      identity: identitySummary(options.identities?.get(instance.id)),
    }));
    return { items };
  });
  app.get('/api/v1/fleet/notifications', async () => options.notifications.summarize());
  app.post('/api/v1/fleet/notifications/queue/retry-all', async () =>
    options.notifications.retryAllQueue(),
  );
  app.post(
    '/api/v1/fleet/notifications/queue/:instanceId/items/:queueId/retry',
    wrapNotificationAction(async (request) =>
      options.notifications.retryQueueItem(request.params.instanceId, request.params.queueId),
    ),
  );
  app.delete(
    '/api/v1/fleet/notifications/queue/:instanceId/items/:queueId',
    wrapNotificationAction(async (request) =>
      options.notifications.deleteQueueItem(request.params.instanceId, request.params.queueId),
    ),
  );
  app.get(
    '/api/v1/fleet/messages',
    wrapMessageAction(async (request) =>
      options.messages.snapshot(parseMessagesQuery(request.query)),
    ),
  );
  app.get(
    '/api/v1/fleet/messages/conversations',
    wrapMessageAction(async (request) => {
      const query = parseMessagesQuery(request.query, MAX_FLEET_CONVERSATION_LIMIT, true);
      await options.messages.refresh();
      const page = options.messages.conversations(query);
      return {
        conversations: page.items.map((item) => ({
          instanceId: item.instanceId,
          instanceName: item.instanceName,
          phoneNumber: item.phoneNumber,
          messageCount: item.messageCount,
          incomingCount: item.incomingCount,
          lastMessage: {
            id: item.lastMessage.id,
            instanceId: item.lastMessage.instanceId,
            instanceName: item.lastMessage.instanceName,
            direction: item.lastMessage.direction,
            phoneNumber: item.lastMessage.phoneNumber,
            content: item.lastMessage.content,
            timestamp: item.lastMessage.timestamp,
            status: item.lastMessage.status,
            transport: item.lastMessage.transport,
          },
        })),
        total: page.totalCount,
        stats: page.stats,
      } satisfies FleetMessageConversationsResponse;
    }),
  );
  app.post(
    '/api/v1/fleet/messages/sync',
    {
      bodyLimit: 4_096,
      schema: {
        body: {
          type: 'object',
          additionalProperties: false,
          properties: {
            instanceId: { type: 'string', minLength: 1, maxLength: 256 },
          },
        },
      },
    },
    wrapMessageAction(async (request) => {
      const body = record(request.body) ?? {};
      const instanceId = typeof body.instanceId === 'string' ? body.instanceId : undefined;
      return instanceId
        ? { synced: await options.messages.syncDevice(instanceId), instanceId }
        : await options.messages.syncAll();
    }),
  );
  app.post(
    '/api/v1/fleet/messages/send',
    {
      bodyLimit: 8_192,
      schema: {
        body: {
          type: 'object',
          additionalProperties: false,
          required: ['instanceId', 'phoneNumber', 'content'],
          properties: {
            instanceId: { type: 'string', minLength: 1, maxLength: 256 },
            phoneNumber: { type: 'string', minLength: 3, maxLength: 32 },
            content: { type: 'string', minLength: 1, maxLength: 2000 },
          },
        },
      },
    },
    wrapMessageAction(async (request) => {
      const value = record(request.body);
      const instanceId = typeof value?.instanceId === 'string' ? value.instanceId : '';
      const phoneNumber = typeof value?.phoneNumber === 'string' ? value.phoneNumber : '';
      const content = typeof value?.content === 'string' ? value.content : '';
      if (!options.outbox) {
        await options.messages.send(instanceId, { phoneNumber, content });
        return { sent: true, queued: false, instanceId };
      }
      // The queue owns a foreign key onto instances, so an unknown node stays a 404.
      if (!(await options.instances.get(instanceId))) throw new MessageServiceError('NOT_FOUND');
      const result = await options.outbox.submit(instanceId, { phoneNumber, content });
      return {
        sent: result.status === 'sent',
        queued: result.status === 'queued',
        instanceId,
        ...(result.item ? { queueId: result.item.id } : {}),
      };
    }),
  );
  app.post(
    '/api/v1/fleet/messages/delete',
    {
      bodyLimit: 32_768,
      schema: {
        body: {
          type: 'object',
          additionalProperties: false,
          required: ['items'],
          properties: {
            items: {
              type: 'array',
              minItems: 1,
              maxItems: 500,
              items: {
                type: 'object',
                additionalProperties: false,
                required: ['instanceId', 'id'],
                properties: {
                  instanceId: { type: 'string', minLength: 1, maxLength: 256 },
                  id: {
                    anyOf: [
                      { type: 'string', minLength: 1, maxLength: 64 },
                      { type: 'integer', minimum: 0 },
                    ],
                  },
                },
              },
            },
          },
        },
      },
    },
    wrapMessageAction(async (request) =>
      options.messages.deleteMany(parseMessageDeleteItems(request.body)),
    ),
  );
  app.get(
    '/api/v1/fleet/messages/outbox',
    wrapMessageAction(async (request) => {
      if (!options.outbox) return { items: [], total: 0, summary: EMPTY_OUTBOX_SUMMARY };
      const query = parseOutboxQuery(request.query);
      const page = options.outbox.list(query);
      const names = new Map((await listInstances(options.instances)).map((i) => [i.id, i.name]));
      return {
        items: page.items.map(
          (item): FleetOutboxItem => ({
            ...item,
            instanceName: names.get(item.instanceId) ?? item.instanceId,
          }),
        ),
        total: page.total,
        summary: options.outbox.summary(),
      };
    }),
  );
  app.post(
    '/api/v1/fleet/messages/outbox/flush',
    wrapMessageAction(async () => {
      if (!options.outbox)
        return { attempted: 0, delivered: 0, deferred: 0, failed: 0, remaining: 0 };
      return await options.outbox.flush();
    }),
  );
  app.post(
    '/api/v1/fleet/messages/outbox/:queueId/cancel',
    wrapMessageAction(async (request) => {
      if (!options.outbox) throw new MessageServiceError('NOT_FOUND');
      const params = record(request.params);
      return options.outbox.cancel(outboxQueueId(params?.queueId));
    }),
  );
  app.post(
    '/api/v1/fleet/messages/outbox/:queueId/retry',
    wrapMessageAction(async (request) => {
      if (!options.outbox) throw new MessageServiceError('NOT_FOUND');
      const params = record(request.params);
      return options.outbox.retry(outboxQueueId(params?.queueId));
    }),
  );
  app.delete(
    '/api/v1/fleet/messages/outbox/:queueId',
    wrapMessageAction(async (request) => {
      if (!options.outbox) throw new MessageServiceError('NOT_FOUND');
      const params = record(request.params);
      const queueId = outboxQueueId(params?.queueId);
      options.outbox.remove(queueId);
      return { removed: true, queueId };
    }),
  );
}