import type { Signal, SignalSource } from '@oo/shared-types';
import { db } from '../db/index.js';
import { integrationTokens } from '../db/schema.js';
import { eq, and } from 'drizzle-orm';
import { bus } from '../events/bus.js';
import { logger } from '../logger.js';

const CACHE_TTL_MS = 30_000;

export function dueAgeDays(due: { date?: string; datetime?: string } | null | undefined): number {
  if (!due) return 0;
  const dateStr = due.datetime ?? due.date;
  if (!dateStr) return 0;
  return Math.max(0, (Date.now() - new Date(dateStr).getTime()) / (1000 * 60 * 60 * 24));
}

export class TodoistSignalSource implements SignalSource {
  readonly id = 'todoist';

  private cache = new Map<string, { signals: Signal[]; fetchedAt: number }>();

  /** Exposed for tests */
  clearCache(userId?: string): void {
    if (userId) this.cache.delete(userId);
    else this.cache.clear();
  }

  getCached(userId: string): Signal[] {
    return this.cache.get(userId)?.signals ?? [];
  }

  async fetchSignals(userId: string): Promise<Signal[]> {
    const entry = this.cache.get(userId);
    if (entry && Date.now() - entry.fetchedAt < CACHE_TTL_MS) return entry.signals;

    const [token] = await db
      .select()
      .from(integrationTokens)
      .where(and(eq(integrationTokens.userId, userId), eq(integrationTokens.provider, 'todoist')))
      .limit(1);

    if (!token) return [];

    const res = await fetch('https://api.todoist.com/api/v1/tasks?filter=today%7Coverdue', {
      headers: { Authorization: `Bearer ${token.accessToken}` },
    });

    if (!res.ok) {
      if (res.status === 401) {
        logger.warn({ userId }, 'todoist: token expired');
        bus.publish('signals.integration.token_expired', {
          userId,
          provider: 'todoist',
          detectedAt: new Date().toISOString(),
        });
        await db
          .update(integrationTokens)
          .set({ tokenStatus: 'needs_reconnect' })
          .where(and(eq(integrationTokens.userId, userId), eq(integrationTokens.provider, 'todoist')));
      }
      return entry?.signals ?? [];
    }

    const body = (await res.json()) as {
      results: Array<{
        id: string;
        content: string;
        priority: number;
        due: { date?: string; datetime?: string; is_recurring?: boolean } | null;
      }>;
    };

    const now = new Date().toISOString();
    const signals: Signal[] = (body.results ?? []).map((t) => {
      const ageDays = dueAgeDays(t.due);
      return {
        id: `todoist:${t.id}`,
        source: 'todoist',
        kind: 'task',
        content: t.content,
        metadata: { todoistId: t.id, due: t.due, priority: t.priority },
        features: {
          is_overdue: ageDays > 0,
          task_age_days: ageDays,
          priority: t.priority ?? 1,
        },
        timestamp: now,
      };
    });

    this.cache.set(userId, { signals, fetchedAt: Date.now() });
    bus.publish('signals.task.synced', { userId, source: 'todoist', count: signals.length, syncedAt: now });

    return signals;
  }

  async act(userId: string, signalId: string, action: string): Promise<void> {
    if (action !== 'done' || !signalId.startsWith('todoist:')) return;
    const todoistId = signalId.slice(8);

    const [tok] = await db
      .select()
      .from(integrationTokens)
      .where(and(eq(integrationTokens.userId, userId), eq(integrationTokens.provider, 'todoist')))
      .limit(1);

    if (!tok) return;

    await fetch(`https://api.todoist.com/api/v1/tasks/${todoistId}/close`, {
      method: 'POST',
      headers: { Authorization: `Bearer ${tok.accessToken}` },
    }).catch(() => {});
  }
}

export const todoistSource = new TodoistSignalSource();