import {
  describe,
  expect,
  it
} from 'vitest';

import {
  buildAttachmentDisplayPinKey,
  canRevokeAttachmentDisplayBlob,
  collectMessageIdsForInactiveRoomBlobRelease,
  shouldRevokeDisplayBlobForAttachment
} from './attachment-blob-eviction.rules';

describe('attachment-blob-eviction rules', () => {
  it('builds a stable pin key from message and attachment ids', () => {
    expect(buildAttachmentDisplayPinKey('msg-1', 'att-1')).toBe('msg-1:att-1');
  });

  it('allows revoking blob urls when a disk path can rehydrate the attachment', () => {
    expect(canRevokeAttachmentDisplayBlob({
      objectUrl: 'blob:http://localhost/abc',
      savedPath: '/appdata/photo.png',
      receivedBytes: 0,
      available: true
    })).toBe(true);
  });

  it('refuses to revoke blobs that are the only local copy', () => {
    expect(canRevokeAttachmentDisplayBlob({
      objectUrl: 'blob:http://localhost/abc',
      receivedBytes: 0,
      available: true
    })).toBe(false);
  });

  it('refuses to revoke blobs while a download is still in progress', () => {
    expect(canRevokeAttachmentDisplayBlob({
      objectUrl: 'blob:http://localhost/abc',
      savedPath: '/appdata/photo.png',
      receivedBytes: 1024,
      available: false
    })).toBe(false);
  });

  it('skips revocation for pinned attachments', () => {
    const attachment = {
      id: 'att-1',
      objectUrl: 'blob:http://localhost/abc',
      savedPath: '/appdata/photo.png',
      receivedBytes: 0,
      available: true
    };

    expect(shouldRevokeDisplayBlobForAttachment(
      'msg-1',
      attachment,
      new Set([buildAttachmentDisplayPinKey('msg-1', 'att-1')])
    )).toBe(false);

    expect(shouldRevokeDisplayBlobForAttachment('msg-1', attachment, new Set())).toBe(true);
  });

  describe('collectMessageIdsForInactiveRoomBlobRelease', () => {
    const messageRoomIds = new Map([
      ['msg-a', 'room-1'],
      ['msg-b', 'room-2'],
      ['msg-c', 'room-2']
    ]);

    it('selects messages that belong to rooms other than the active one', () => {
      expect(collectMessageIdsForInactiveRoomBlobRelease(
        [
          'msg-a',
          'msg-b',
          'msg-c'
        ],
        (messageId) => messageRoomIds.get(messageId) ?? null,
        'room-1'
      )).toEqual(['msg-b', 'msg-c']);
    });

    it('skips messages with an unknown room so they are not evicted by mistake', () => {
      expect(collectMessageIdsForInactiveRoomBlobRelease(
        ['msg-a', 'msg-unknown'],
        (messageId) => messageRoomIds.get(messageId) ?? null,
        'room-2'
      )).toEqual(['msg-a']);
    });

    it('selects every known-room message when no room is active', () => {
      expect(collectMessageIdsForInactiveRoomBlobRelease(
        ['msg-a', 'msg-b'],
        (messageId) => messageRoomIds.get(messageId) ?? null,
        null
      )).toEqual(['msg-a', 'msg-b']);
    });
  });
});