import type { CodingProjectService } from '../coding-projects/project-service';
import type { CodingConversationRuntime } from '../coding-runtime/contracts';
import { readCodingConversationHistory } from '../coding-projects/conversation-history';
import { sourceContext } from './context';
import { TeacherError } from './config-client';
import type { TeacherSourceContext } from '../../shared/coding-teacher';

export async function readTeacherSource(
  projects: CodingProjectService,
  runtime: CodingConversationRuntime,
  userDataDir: string,
  projectId: string,
  sourceId: string
): Promise<TeacherSourceContext> {
  const project = await projects.getProject(projectId);
  const conversation = await projects.conversationStore(project.path).get(sourceId);
  if (!conversation) throw new TeacherError(404, 'teacher_source_not_found', '来源会话不存在。');
  try {
    const snapshot = await runtime.getSnapshot(sourceId);
    if (snapshot.conversation.projectId === projectId) return sourceContext(snapshot);
  } catch {
    /* Cold history does not require a running worker. */
  }
  try {
    return sourceContext(await readCodingConversationHistory(userDataDir, projectId, conversation));
  } catch {
    throw new TeacherError(
      409,
      'teacher_source_unreadable',
      '暂时无法读取来源会话，请先打开该会话。'
    );
  }
}