import type { PhaseEvent } from '../types/workbench';

/** 后端 phase 事件载荷（与 StreamEvent['phase'] 结构兼容，保持 mapper 独立可测） */
export type PhaseEventPayload = {
  phase_id?: string;
  message?: string;
  role?: string;
  step_index?: number;
  total_steps?: number;
  progress?: number;
};

/** phase_id → 图标/短标签映射（与 bizdev-cli/main.go 的 CLI 映射保持一致） */
const PHASE_META: Record<string, { icon: string; label: string }> = {
  squad_assembly: { icon: '👥', label: '组建小队' },
  knowledge_retrieval: { icon: '📚', label: '知识检索' },
  knowledge_retrieved: { icon: '📚', label: '知识命中' },
  step_executing: { icon: '⚙️', label: '专员执行' },
  step_completed: { icon: '✅', label: '步骤完成' },
  quality_gate: { icon: '🛡️', label: '质量门禁' },
  advisor_briefing: { icon: '💡', label: '参谋简报' },
  stage_transition: { icon: '🚀', label: '阶段跃迁' },
  stage_started: { icon: '🚀', label: '阶段启动' },
  stage_completed: { icon: '🎉', label: '阶段完成' },
  task_failed: { icon: '⚠️', label: '任务异常' },
};

/** 收口型 phase：不追加新节点，仅把当前 running 条目置为 completed */
const CLOSE_PHASES = new Set(['step_completed', 'stage_completed']);

function decorateLabel(base: string, phase: PhaseEventPayload): string {
  const { step_index, total_steps, progress } = phase;
  if (step_index && step_index > 0 && total_steps && total_steps > 0) {
    return `${base}（第 ${step_index}/${total_steps} 步）`;
  }
  if (progress && progress > 0) {
    return `${base}（${progress}%）`;
  }
  return base;
}

/** 条目 key：同 phase 且无有效 step_index 时刷新文案；带 step_index 的重复 phase 各占一节点 */
function stepKeyOf(phase: PhaseEventPayload): string {
  const idx = phase.step_index ?? 0;
  return idx > 0 ? `${phase.phase_id}#${idx}` : `${phase.phase_id}`;
}

/**
 * applyPhaseEvent 把一条后端 phase 事件折叠进 PhaseEventStrip 序列（纯函数）。
 * 进度求真：仅由真实 phase 事件驱动，无任何人为进度推演。
 */
export function applyPhaseEvent(strip: PhaseEvent[], phase?: PhaseEventPayload): PhaseEvent[] {
  if (!phase?.phase_id) return strip;

  const meta = PHASE_META[phase.phase_id] ?? { icon: '⏳', label: '任务推进' };
  // 进度求真：优先展示后端下发的真实进度文案，短标签仅作缺省
  const base = phase.message?.trim() || meta.label;
  const label = decorateLabel(base, phase);
  const key = stepKeyOf(phase);

  // 已存在的条目：仅刷新文案（同阶段/同步骤进度更新）
  const existingIdx = strip.findIndex((e) => e.step === key);
  if (existingIdx >= 0) {
    return strip.map((e, i) => (i === existingIdx ? { ...e, label } : e));
  }

  // 收口型 phase：running 条目置 completed，不追加新节点
  if (CLOSE_PHASES.has(phase.phase_id)) {
    return strip.map((e) => (e.status === 'running' ? { ...e, status: 'completed' as const } : e));
  }

  // 新 phase：先行条目全部置 completed，追加当前节点为 running
  const settled = strip.map((e) =>
    e.status === 'running' ? { ...e, status: 'completed' as const } : e
  );
  return [
    ...settled,
    { step: key, icon: meta.icon, label, status: 'running' as const },
  ];
}