"use client";

import { useState } from "react";
import { Check, RotateCcw, Square, X } from "lucide-react";

import { ThinkingIndicator } from "@/components/ThinkingIndicator";
import { Button } from "@/components/ui/Button";
import { SectionHeader } from "@/components/ui/SectionHeader";
import { StatusNote } from "@/components/ui/StatusNote";
import { TextArea } from "@/components/ui/TextArea";
import { friendlyError } from "@/lib/errors/messages";
import { useChapterRewrite } from "@/lib/workbench/useChapterRewrite";

interface ChapterRewritePanelProps {
  projectId: string;
  chapterNo: number;
  // 当前整章正文（首轮重写的 prior_draft）。
  currentDraft: string;
  // 接受某一版 → 替换整章正文（HITL，作者显式点选才落草稿）。
  onAccept: (text: string) => void;
  onClose: () => void;
}

// 整章「再沟通 / 重写」结果卡（内联，非模态）：作者给意见 → AI 就着当前整章 + 完整记忆注入
// 流式重写一版 → 版本栈可多轮迭代 → 接受某版才替换整章正文。生成不写库（HITL，不变量 #3）。
export function ChapterRewritePanel({
  projectId,
  chapterNo,
  currentDraft,
  onAccept,
  onClose,
}: ChapterRewritePanelProps) {
  const rewrite = useChapterRewrite();
  const [feedback, setFeedback] = useState("");

  const hasVersions = rewrite.versions.length > 0;
  const canSend = feedback.trim().length > 0 && !rewrite.isStreaming;
  // 下一轮以最新版正文为基础（无版本则用当前整章正文）迭代。
  const priorDraft = rewrite.latest?.text ?? currentDraft;
  const err = rewrite.state.phase === "error" ? rewrite.state.error : null;

  const onSend = (): void => {
    if (!canSend) return;
    const fb = feedback.trim();
    setFeedback("");
    void rewrite.send(projectId, chapterNo, fb, priorDraft);
  };

  return (
    <div className="max-h-[70vh] overflow-auto border-b border-line bg-panel px-4 py-3 sm:px-6">
      <div className="flex items-center justify-between gap-3">
        <SectionHeader
          title="对整章再沟通 / 重写"
          description="给意见 → AI 就着当前整章 + 完整设定重写一版；不满意可再给意见迭代，满意再替换正文。"
        />
        <Button onClick={onClose} variant="ghost" size="icon" aria-label="关闭整章重写">
          <X className="h-4 w-4" aria-hidden="true" />
        </Button>
      </div>

      <div className="mt-3 space-y-2">
        <label className="block">
          <span className="sr-only">修改意见</span>
          <TextArea
            value={feedback}
            onChange={(e) => setFeedback(e.target.value)}
            rows={2}
            placeholder={
              hasVersions
                ? "对这一版还想怎么改？（如「高潮再拉满」「删掉第 2 段闪回」）"
                : "这一章哪里不满意？想怎么改？"
            }
          />
        </label>
        <div className="flex flex-wrap items-center gap-2">
          {rewrite.isStreaming ? (
            <Button onClick={rewrite.stop} variant="danger" size="sm">
              <Square className="h-4 w-4" aria-hidden="true" />
              停
            </Button>
          ) : (
            <Button onClick={onSend} disabled={!canSend} variant="primary" size="sm">
              <RotateCcw className="h-4 w-4" aria-hidden="true" />
              {hasVersions ? "再改一版" : "重写整章"}
            </Button>
          )}
          {rewrite.isStreaming ? (
            <ThinkingIndicator label="重写中" className="text-xs text-cinnabar" />
          ) : null}
        </div>
        {err ? (
          <StatusNote variant="danger" className="text-xs" title="整章重写失败">
            <p>{friendlyError(err.code, err.message).text}</p>
          </StatusNote>
        ) : null}
      </div>

      {rewrite.isStreaming && rewrite.state.text ? (
        <figure className="mt-3 rounded border border-cinnabar/40 bg-bg p-3">
          <figcaption className="mb-1 text-2xs text-ink-soft">生成中…</figcaption>
          <p className="whitespace-pre-wrap text-sm text-ink">{rewrite.state.text}</p>
        </figure>
      ) : null}

      {hasVersions && !rewrite.isStreaming ? (
        <ul className="mt-3 space-y-2">
          {[...rewrite.versions].reverse().map((version, i) => {
            const versionNo = rewrite.versions.length - i;
            return (
              <li key={versionNo} className="rounded border border-line bg-bg p-3">
                <div className="mb-1 flex flex-wrap items-center justify-between gap-2">
                  <span className="text-2xs text-ink-soft">
                    第 {versionNo} 版 · 意见：{version.feedback}
                  </span>
                  <Button onClick={() => onAccept(version.text)} variant="primary" size="sm">
                    <Check className="h-4 w-4" aria-hidden="true" />
                    接受这版（替换整章正文）
                  </Button>
                </div>
                <p className="max-h-48 overflow-auto whitespace-pre-wrap text-sm text-ink">
                  {version.text}
                </p>
              </li>
            );
          })}
        </ul>
      ) : null}
    </div>
  );
}