import { randomUUID } from 'node:crypto';
import type { AgentEvent, AgentEventKind } from './types';

/**
 * 移植自 Noobi.ai src/main/eventMapper.ts。
 * 删掉了整块 stage 推断（那是游戏流水线专用）与 planner/implementer/reviewer 角色标签，
 * 事件维度改成 threadId；也删掉了 imageGeneration / dynamicToolCall 这类 Noobi 自有素材工具。
 */

const UNTHREADED = 'unthreaded';

export function threadIdOf(notification: { params?: unknown }): string {
  const params = asRecord(notification.params);
  const turn = asRecord(params?.turn);
  const item = asRecord(params?.item);
  return (
    readString(params?.threadId) ?? readString(turn?.threadId) ?? readString(item?.threadId) ?? UNTHREADED
  );
}

export function notificationToEvent(notification: {
  method: string;
  params?: unknown;
}): AgentEvent | null {
  const params = asRecord(notification.params) ?? {};
  const item = asRecord(params.item);
  const turn = asRecord(params.turn);
  const threadId = threadIdOf(notification);
  const turnId = readString(params.turnId) ?? readString(turn?.id) ?? 'turn';
  let itemId = readString(params.itemId) ?? readString(item?.id) ?? undefined;
  const method = notification.method;
  let kind: AgentEventKind = 'lifecycle';
  let title = 'Codex';
  let message = '';
  let isDelta = false;

  switch (method) {
    case 'item/agentMessage/delta':
      kind = 'assistant';
      title = '回复';
      message = readString(params.delta) ?? '';
      isDelta = true;
      break;
    case 'item/reasoning/summaryTextDelta':
      kind = 'thought';
      title = '思考摘要';
      message = readString(params.delta) ?? '';
      isDelta = true;
      break;
    case 'item/commandExecution/outputDelta':
      kind = 'tool';
      title = '命令输出';
      message = readString(params.delta) ?? '';
      isDelta = true;
      break;
    case 'turn/plan/updated':
      kind = 'plan';
      title = '计划更新';
      message = describe(params.plan ?? params);
      break;
    case 'item/fileChange/patchUpdated':
      kind = 'file';
      title = '文件变更';
      message = readString(params.patch) ?? readString(params.diff) ?? '正在生成补丁';
      isDelta = true;
      break;
    case 'item/started':
    case 'item/completed': {
      const type = readString(item?.type) ?? 'item';
      const presentation = describeItem(item, type);
      kind = presentation.kind;
      title = presentation.title;
      message = presentation.message || (method === 'item/completed' ? '已完成' : '已开始');
      break;
    }
    case 'turn/started':
      title = '回合开始';
      // 自部署端点在首字之前整段静默是正常现象，先把预期讲清楚，免得被当成卡死
      message = 'Codex 已开始处理当前任务；端点要把完整上下文重新 prefill，首字之前不会有任何输出';
      break;
    case 'thread/tokenUsage/updated': {
      // 形状取自 rust-v0.155.1 ServerNotification.json：
      // params.tokenUsage = { last, total, modelContextWindow:int64 }，last/total 都是 TokenUsageBreakdown
      const usage = asRecord(params.tokenUsage);
      const last = asRecord(usage?.last) ?? asRecord(usage?.total);
      const input = readNumber(last?.inputTokens);
      const cached = readNumber(last?.cachedInputTokens);
      const output = readNumber(last?.outputTokens);
      const window = readNumber(usage?.modelContextWindow);
      kind = 'lifecycle';
      title = '上下文用量';
      itemId = 'tokenUsage';
      message =
        `本轮请求：输入 ${formatTokens(input)} tokens` +
        (cached ? `（命中缓存 ${formatTokens(cached)}）` : '') +
        `｜输出 ${formatTokens(output)} tokens` +
        (window ? `｜上下文窗口 ${formatTokens(window)} tokens` : '');
      break;
    }
    case 'turn/completed':
      title = '回合结束';
      message = `状态：${readString(turn?.status) ?? 'completed'}`;
      break;
    case 'error':
      kind = 'error';
      title = '运行错误';
      message = readString(params.message) ?? readString(asRecord(params.error)?.message) ?? describe(params);
      break;
    case 'warning':
    case 'configWarning':
      kind = 'error';
      title = '警告';
      message = readString(params.message) ?? describe(params);
      break;
    default:
      return null;
  }

  if (!message) return null;
  return {
    id: itemId ? `${threadId}:${turnId}:${itemId}:${kind}` : randomUUID(),
    threadId,
    turnId,
    kind,
    title,
    message: clip(message),
    timestamp: new Date().toISOString(),
    method,
    ...(itemId ? { itemId } : {}),
    ...(isDelta ? { isDelta: true } : {}),
  };
}

function describeItem(
  item: Record<string, unknown> | null,
  type: string,
): { kind: AgentEventKind; title: string; message: string } {
  if (!item) return { kind: 'lifecycle', title: type, message: '' };
  switch (type) {
    case 'agentMessage':
      return { kind: 'assistant', title: '回复', message: readString(item.text) ?? '' };
    case 'reasoning':
      return {
        kind: 'thought',
        title: '推理摘要',
        message: readTextArray(item.summary) || readTextArray(item.content),
      };
    case 'commandExecution':
      return {
        kind: 'tool',
        title: '执行命令',
        message: readString(item.command) ?? describe(item.commandActions ?? item),
      };
    case 'fileChange':
      return { kind: 'file', title: '修改文件', message: describe(item.changes ?? item) };
    case 'mcpToolCall':
      return {
        kind: 'tool',
        title: `工具 ${cleanToolName(readString(item.tool))}`.trim(),
        message: describe(item.arguments ?? item.result ?? item),
      };
    case 'plan':
      return { kind: 'plan', title: '计划', message: describe(item) };
    default:
      return { kind: 'lifecycle', title: type, message: describe(item) };
  }
}

function readTextArray(value: unknown): string {
  if (!Array.isArray(value)) return '';
  return value
    .map((entry) => (typeof entry === 'string' ? entry : readString(asRecord(entry)?.text) ?? ''))
    .filter(Boolean)
    .join('\n');
}

function describe(value: unknown): string {
  if (typeof value === 'string') return value;
  try {
    return JSON.stringify(value, null, 2);
  } catch {
    return String(value);
  }
}

function clip(value: string, maxLength = 24_000): string {
  return value.length > maxLength ? `${value.slice(0, maxLength)}\n…（已截断）` : value;
}

function cleanToolName(value: string | null): string {
  return value?.replace(/[^A-Za-z0-9_.-]/gu, '').slice(0, 128) ?? '';
}

function asRecord(value: unknown): Record<string, unknown> | null {
  return value && typeof value === 'object' && !Array.isArray(value)
    ? (value as Record<string, unknown>)
    : null;
}

function readString(value: unknown): string | null {
  return typeof value === 'string' ? value : null;
}

function readNumber(value: unknown): number | null {
  return typeof value === 'number' && Number.isFinite(value) ? value : null;
}

/** 46122 → "4.6 万"：给页面读的，不是给机器算的 */
function formatTokens(value: number | null): string {
  if (value === null) return '未知';
  if (value >= 10_000) return `${(value / 10_000).toFixed(1)} 万`;
  return String(value);
}