import type { AppSupabaseClient } from '../supabase/client';

// `@anna_b` style — letters, digits, underscore, dot, dash, 2-32 chars.
// Conservative on purpose: false negatives (a real username we don't match)
// are recoverable (no notification fires); false positives (matching a
// non-username) just become an INSERT that the FK check rejects.
const MENTION_RE = /(?:^|[\s,;:!?(])@([a-zA-Z0-9_.-]{2,32})/g;

export function parseMentionUsernames(plaintext: string): string[] {
  const out = new Set<string>();
  for (const m of plaintext.matchAll(MENTION_RE)) {
    if (m[1]) out.add(m[1].toLowerCase());
  }
  return [...out];
}

export interface MentionResolver {
  // Resolves an array of @usernames in this conversation to user-ids.
  // Returns only memberships that exist + are accepted.
  resolveUsernames(conversationId: string, usernames: string[]): Promise<Map<string, string>>;
}

export function makeMentionResolver(client: AppSupabaseClient): MentionResolver {
  return {
    async resolveUsernames(conversationId, usernames) {
      if (usernames.length === 0) return new Map();
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      const { data, error } = await (client as any)
        .from('conversation_members')
        .select('user_id, accepted, profiles!inner(username)')
        .eq('conversation_id', conversationId)
        .eq('accepted', true)
        .in('profiles.username', usernames);
      if (error) throw error;
      const out = new Map<string, string>();
      for (const row of (data ?? []) as Array<{ user_id: string; profiles: { username: string } }>) {
        out.set(row.profiles.username.toLowerCase(), row.user_id);
      }
      return out;
    },
  };
}

export async function insertMentions(
  client: AppSupabaseClient,
  messageId: string,
  conversationId: string,
  mentionedUserIds: string[],
): Promise<void> {
  if (mentionedUserIds.length === 0) return;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const { error } = await (client as any).from('message_mentions').insert(
    mentionedUserIds.map((uid) => ({
      message_id: messageId,
      mentioned_user_id: uid,
      conversation_id: conversationId,
    })),
  );
  if (error) throw error;
}