import { useMutation, useQueryClient } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { isAdminPubkey } from '@/lib/admins';
import { addLocalHidden } from '@/lib/localModeration';
import { toast } from '@/hooks/useToast';
import type { NostrEvent } from '@nostrify/nostrify';

/**
 * DIAGNOSTIC DELETE
 * =================
 * We could not identify WHERE the delete hangs (signing? relay publish?), so
 * this version narrates every step on-screen via toasts and splits the flow into
 * explicit, independently-timed phases:
 *
 *   1. SIGN  — call the signer (Amber). Own timeout. If it hangs here, Amber
 *              never returned (app↔Amber problem).
 *   2. PUBLISH — send the signed event to relays. Own timeout. If it hangs here,
 *              the relay is the problem, not Amber.
 *
 * Whatever step is on screen when it freezes tells us EXACTLY what to fix.
 */

const SIGN_TIMEOUT_MS = 90_000; // matches the signer's own cap
const PUBLISH_TIMEOUT_MS = 20_000; // relays should answer well within this

function withTimeout<T>(promise: Promise<T>, ms: number, label: string): Promise<T> {
  return new Promise<T>((resolve, reject) => {
    const timer = setTimeout(() => {
      reject(new Error(`${label} timed out after ${Math.round(ms / 1000)}s.`));
    }, ms);
    promise.then(
      (v) => {
        clearTimeout(timer);
        resolve(v);
      },
      (e) => {
        clearTimeout(timer);
        reject(e);
      },
    );
  });
}

export function useDeleteEntity() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: ({
      event,
      reason,
    }: {
      event: NostrEvent;
      reason?: string;
    }) => runDelete(event, reason),
    onSuccess: () => {
      queryClient.invalidateQueries();
    },
  });

  async function runDelete(event: NostrEvent, reason?: string): Promise<void> {
    if (!user) throw new Error('You must be logged in to delete.');

    const isOwner = user.pubkey === event.pubkey;
    const isAdmin = isAdminPubkey(user.pubkey);
    if (!isOwner && !isAdmin) {
      throw new Error('You can only delete your own listing.');
    }

    const dTag = event.tags.find(([name]) => name === 'd')?.[1] ?? '';
    const coord = `${event.kind}:${event.pubkey}:${dTag}`;

    const deletionTags: string[][] = [
      ['a', coord],
      ['e', event.id],
      ['k', String(event.kind)],
    ];

    const template = {
      kind: 5,
      content: reason?.trim() || '',
      tags: deletionTags,
      created_at: Math.floor(Date.now() / 1000),
    };

    // ── PHASE 1: SIGN ────────────────────────────────────────────────────────
    // With the Amethyst-style foreground signer, Amber pops up its Approve/Reject
    // screen directly — no more silent ContentProvider stall. The signer has its
    // own graceful timeout, but we keep an outer guard as a belt-and-braces.
    toast({
      title: 'Approve in Amber',
      description: 'Amber will open — tap Approve to confirm the deletion.',
    });

    if (!user.signer) {
      throw new Error('No signer available. Please log in again.');
    }

    let signed: NostrEvent;
    try {
      signed = await withTimeout(
        user.signer.signEvent(template),
        SIGN_TIMEOUT_MS,
        'Signing (Amber)',
      );
    } catch (e) {
      const msg = e instanceof Error ? e.message : String(e);
      // Distinguish a deliberate rejection from a real failure.
      if (/reject/i.test(msg)) {
        toast({ title: 'Cancelled', description: 'You rejected the request in Amber.' });
        throw new Error('Signing cancelled.');
      }
      toast({
        title: "Couldn't sign",
        description: msg,
        variant: 'destructive',
      });
      throw new Error(`SIGN step failed: ${msg}`);
    }

    // ── PHASE 2: PUBLISH ─────────────────────────────────────────────────────
    toast({
      title: 'Step 2/2: Publishing…',
      description: 'Sending the deletion to relays.',
    });

    try {
      await withTimeout(
        nostr.event(signed),
        PUBLISH_TIMEOUT_MS,
        'Publishing (relays)',
      );
    } catch (e) {
      const msg = e instanceof Error ? e.message : String(e);
      // The event was SIGNED fine — the relay is the slow/failing part. Hide it
      // locally so the user's action still takes visible effect on this device.
      if (isAdmin && !isOwner) addLocalHidden({ coord, id: event.id });
      toast({
        title: 'Stuck at PUBLISHING',
        description: `Relay step failed: ${msg}. It was signed OK; the relay didn't confirm.`,
        variant: 'destructive',
      });
      throw new Error(`PUBLISH step failed: ${msg}`);
    }

    // Admin: hide locally too (no signature needed).
    if (isAdmin && !isOwner) {
      addLocalHidden({ coord, id: event.id });
    }

    toast({ title: 'Deleted', description: 'The deletion was signed and published.' });
  }
}