import { z } from "zod";
import type { EditCandidate } from "./contract";

export const MIN_SEQUENCE_MATCH_SCORE = 60;
export class HighlightValidationError extends Error {
  constructor(message: string) { super(message); this.name = "HighlightValidationError"; }
}

const highlightResultSchema = z.object({
  selections: z.array(z.object({
    id: z.string(),
    startSeconds: z.number().finite().min(0),
    transition: z.enum(["cut", "fade"]),
    reason: z.string().trim().min(1).max(300),
    matchScore: z.number().finite().min(0).max(100),
    visualIssues: z.array(z.string().trim().min(1).max(160)).max(10).default([]),
  })).min(1).max(12),
  summary: z.string().max(1000).default(""),
});
export type SequenceHighlight = z.infer<typeof highlightResultSchema>["selections"][number];

export function validateSequenceHighlights(value: unknown, candidates: EditCandidate[], shotDurations: number[]) {
  const parsed = highlightResultSchema.safeParse(value);
  if (!parsed.success) throw new HighlightValidationError("视频高光分析格式无效，未提交成片合成");
  const result = parsed.data;
  if (shotDurations.length !== candidates.length || result.selections.length !== candidates.length ||
      new Set(result.selections.map(item => item.id)).size !== candidates.length ||
      result.selections.some((item, index) => item.id !== candidates[index].id))
    throw new HighlightValidationError("视频高光分析遗漏、重复或更改了分镜顺序，未提交成片合成");
  for (const [index, item] of result.selections.entries()) {
    const available = (candidates[index].end - candidates[index].start) / 1_000_000;
    const wanted = shotDurations[index];
    if (!Number.isFinite(wanted) || wanted <= 0 || item.startSeconds + wanted > available + 0.001)
      throw new HighlightValidationError(`镜头 ${index + 1} 的高光区间超出真实视频长度，请重新选片`);
    if (index === 0 && item.transition !== "cut")
      throw new HighlightValidationError("首镜头的转场分析无效，请重新选片");
    if (item.visualIssues.length)
      throw new HighlightValidationError(`镜头 ${index + 1} 存在画面违规：${item.visualIssues.join("；")}。请替换或重新生成该镜头后再合成`);
    if (item.matchScore < MIN_SEQUENCE_MATCH_SCORE)
      throw new HighlightValidationError(`镜头 ${index + 1} 未达到需求匹配门槛（${item.matchScore}/${MIN_SEQUENCE_MATCH_SCORE}）：${item.reason}。请替换或重新生成该镜头后再合成`);
  }
  return result;
}