import { getBackendBaseURL } from '@/core/config';
import { apiFetch } from '@/core/api';

import type { ProgressEvent, CompletedIntervention } from '../types/ai-writing';

export interface AIWritingSessionSummary {
  id: string;
  user_id: string | null;
  title: string;
  user_intent: string | null;
  status: string;
  draft_title: string | null;
  draft_markdown: string | null;
  completed_interventions: CompletedInterventionRecord[] | null;
  review_result: Record<string, unknown> | null;
  transcript: AIWritingTranscript | null;
  created_at: string;
  updated_at: string;
}

export interface CompletedInterventionRecord {
  pausePoint: string;
  action: string;
  timestamp: string;
}

/** 完整对话时间线快照：与实时对话用同一份数据结构，历史回显时直接喂给 AIWritingTimeline。 */
export interface AIWritingTranscript {
  progressEvents: ProgressEvent[];
  completedInterventions: CompletedIntervention[];
}

const BASE = () => `${getBackendBaseURL()}/api/ai-writing/sessions`;

// ── admin 调试用 —— 阶段 7 删冗余时一并移除 ───────────────────────────────────
export interface AIWritingCleanupResult {
  deleted_db: number;
  deleted_checkpoints: number;
  skipped_active: number;
  elapsed_seconds: number;
  params: { retention_days: number; only_finished: boolean; batch_size: number };
}

/** 仅 admin 可用：触发一次性会话清理（保留 ai-writing-优化.md 迁移期临时调试入口）。 */
export async function adminCleanupAIWritingSessions(body: {
  retention_days?: number;
  only_finished?: boolean;
  batch_size?: number;
} = {}): Promise<AIWritingCleanupResult> {
  const resp = await apiFetch(`${getBackendBaseURL()}/api/ai-writing/admin/cleanup`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(body),
  });
  if (!resp.ok) {
    const text = await resp.text().catch(() => '');
    throw new Error(`清理失败 ${resp.status}: ${text || resp.statusText}`);
  }
  return resp.json();
}


export async function listAIWritingSessions(): Promise<AIWritingSessionSummary[]> {
  const resp = await apiFetch(BASE());
  if (!resp.ok) throw new Error(`获取历史记录失败: ${resp.status}`);
  return resp.json();
}

export async function getAIWritingSession(id: string): Promise<AIWritingSessionSummary> {
  const resp = await apiFetch(`${BASE()}/${id}`);
  if (!resp.ok) throw new Error(`获取会话失败: ${resp.status}`);
  return resp.json();
}

export async function renameAIWritingSession(id: string, title: string): Promise<AIWritingSessionSummary> {
  const resp = await apiFetch(`${BASE()}/${id}`, {
    method: 'PATCH',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ title }),
  });
  if (!resp.ok) throw new Error(`重命名失败: ${resp.status}`);
  return resp.json();
}

export async function deleteAIWritingSession(id: string): Promise<void> {
  const resp = await apiFetch(`${BASE()}/${id}`, { method: 'DELETE' });
  if (!resp.ok) throw new Error(`删除失败: ${resp.status}`);
}

/**
 * 保存会话的完整对话时间线，供历史回显出与实时对话一致的富时间线。
 *
 * 该功能属于「锦上添花」：保存失败不应影响写作主流程，因此本函数永不抛错，
 * 内部捕获所有异常（网络错误 / 接口 500 等），仅打印告警并返回是否成功。
 */
export async function saveAIWritingTranscript(
  id: string,
  transcript: AIWritingTranscript,
): Promise<boolean> {
  try {
    const resp = await apiFetch(`${BASE()}/${id}/transcript`, {
      method: 'PUT',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ transcript }),
    });
    if (!resp.ok) {
      console.warn(`[ai-writing] 保存对话时间线失败: HTTP ${resp.status}（已忽略，不影响写作流程）`);
      return false;
    }
    return true;
  } catch (err) {
    console.warn('[ai-writing] 保存对话时间线异常（已忽略，不影响写作流程）:', err);
    return false;
  }
}