import type { TaskStateDetailsV1 } from '../../contracts';

export interface TaskStateToolResult {
  content: Array<{ type: 'text'; text: string }>;
  details: TaskStateDetailsV1;
}

export function projectTaskState(input: unknown): TaskStateToolResult {
  if (!input || typeof input !== 'object' || Array.isArray(input)) throw new Error('Task state is invalid');
  const tasks = (input as { tasks?: unknown }).tasks;
  if (!Array.isArray(tasks) || tasks.length === 0 || tasks.length > 100) {
    throw new Error('Task state requires one to one hundred tasks');
  }
  const ids = new Set<string>();
  const projected: TaskStateDetailsV1['tasks'] = tasks.map((candidate) => {
    if (!candidate || typeof candidate !== 'object' || Array.isArray(candidate)) {
      throw new Error('Task state item is invalid');
    }
    const item = candidate as Record<string, unknown>;
    const id = typeof item.id === 'string' ? item.id.trim() : '';
    const title = typeof item.title === 'string' ? item.title.trim() : '';
    if (!id || id.length > 128 || ids.has(id) || !title || title.length > 500
      || !['pending', 'running', 'complete', 'error'].includes(String(item.status))) {
      throw new Error('Task state item is invalid');
    }
    ids.add(id);
    return {
      id,
      title,
      status: item.status as TaskStateDetailsV1['tasks'][number]['status'],
    };
  });
  const details: TaskStateDetailsV1 = { schema: 'task-state.v1', tasks: projected };
  return {
    content: [{
      type: 'text',
      text: `${projected.filter(({ status }) => status === 'complete').length}/${projected.length} tasks complete`,
    }],
    details,
  };
}