/**
 * Parse Claude Agent SDK TodoWrite tool input into a stable checklist model
 * for Feishu card progress rendering (Manus-style live todos).
 */

export type AgentTodoStatus = "pending" | "in_progress" | "completed";

export interface AgentTodoItem {
  readonly content: string;
  readonly status: AgentTodoStatus;
  /** Present-tense label while the item is active, when the model supplies it. */
  readonly activeForm: string | undefined;
}

const STATUSES = new Set<AgentTodoStatus>(["pending", "in_progress", "completed"]);

/** True when the tool name is the SDK TodoWrite dispatcher. */
export function isTodoWriteTool(toolName: string): boolean {
  return toolName === "TodoWrite" || toolName.endsWith("__TodoWrite");
}

/**
 * Extract the full todo list from a TodoWrite tool_use input.
 * Returns null when the payload is not a usable TodoWrite body.
 */
export function parseTodoWriteInput(input: unknown): readonly AgentTodoItem[] | null {
  if (typeof input !== "object" || input === null || Array.isArray(input)) return null;
  if (!("todos" in input)) return null;
  const rawTodos = (input as { todos?: unknown }).todos;
  if (!Array.isArray(rawTodos) || rawTodos.length === 0) return null;

  const todos: AgentTodoItem[] = [];
  for (const raw of rawTodos) {
    if (typeof raw !== "object" || raw === null || Array.isArray(raw)) continue;
    const record = raw as Record<string, unknown>;
    const content = typeof record.content === "string" ? record.content.trim() : "";
    if (content === "") continue;
    const statusRaw = typeof record.status === "string" ? record.status : "pending";
    const status: AgentTodoStatus = STATUSES.has(statusRaw as AgentTodoStatus)
      ? (statusRaw as AgentTodoStatus)
      : "pending";
    const activeForm =
      typeof record.activeForm === "string" && record.activeForm.trim() !== ""
        ? record.activeForm.trim()
        : undefined;
    todos.push({ content, status, activeForm });
  }
  return todos.length === 0 ? null : todos;
}

export function todoProgressSummary(todos: readonly AgentTodoItem[]): {
  readonly completed: number;
  readonly total: number;
  readonly inProgress: number;
} {
  let completed = 0;
  let inProgress = 0;
  for (const todo of todos) {
    if (todo.status === "completed") completed += 1;
    else if (todo.status === "in_progress") inProgress += 1;
  }
  return { completed, total: todos.length, inProgress };
}