"use client";

import { useEffect, useMemo, useState } from "react";
import { useRouter } from "next/navigation";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogDescription,
  DialogFooter,
} from "@/components/ui/dialog";
import {
  Loader2,
  AlertCircle,
  Package,
  Hash,
  Calendar,
  GitBranch,
  PackageOpen,
  ArrowUpRight,
  FileText,
  History,
  Monitor,
  Apple,
  Terminal,
} from "lucide-react";
import { cn } from "@/lib/utils";
import { ReleaseNotes } from "@/components/release-notes";
import { PlatformDownloadGrid } from "@/components/platform-download-grid";
import {
  DOWNLOAD_SOURCES,
  resolveDownloadUrl,
  buildDownloadThanksUrl,
  type DownloadSourceKey,
  type DownloadOsKey,
} from "@/lib/download-sources";

interface License {
  isNeedAgreat: string;
  title: string;
  text: string;
  liceURL: string;
}

interface PlatformInfo {
  isNoVersion: string;
  licence: License;
  DownlodeURL: string;
}

interface AppInfo {
  windows: PlatformInfo;
  macos: PlatformInfo;
  linux: PlatformInfo;
}

interface AboutVersion {
  about: string;
  "about-list": Record<string, string>;
}

/** 历史预览版条目（与顶层字段同构，可覆盖到页面上） */
interface BetaVersionItem {
  version: string;
  builddate: string;
  tag?: string;
  htmlUrl?: string;
  releaseNotes?: string;
  app: AppInfo;
}

interface BetaData {
  version: string;
  builddate: string;
  /** 数据来源：github = GitHub Releases 自动识别；legacy = 旧静态源兜底 */
  source?: "github" | "legacy";
  tag?: string;
  htmlUrl?: string;
  releaseNotes?: string;
  /** GitHub 可达但没有预览版时的标记 */
  noRelease?: boolean;
  app: AppInfo;
  aboutversion?: AboutVersion;
  /** 历史预览版列表（新 -> 旧） */
  versions?: BetaVersionItem[];
}

const PLATFORM_SLOTS = ["windows", "macos", "linux"] as const;

export default function JoinBetaPage() {
  const router = useRouter();
  const [data, setData] = useState<BetaData | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [dialogOpen, setDialogOpen] = useState(false);
  const [activePlatform, setActivePlatform] = useState<PlatformInfo | null>(null);
  const [pendingOs, setPendingOs] = useState<DownloadOsKey>("windows");
  const [downloadSource, setDownloadSource] = useState<DownloadSourceKey>("github");
  /** null = 最新预览版（顶层数据），否则为 data.versions 中的历史版本号 */
  const [selectedVersion, setSelectedVersion] = useState<string | null>(null);

  useEffect(() => {
    fetch("/api/beta-version")
      .then((res) => {
        if (!res.ok) throw new Error(`HTTP ${res.status}`);
        return res.json();
      })
      .then((json: BetaData) => {
        setData(json);
        setLoading(false);
      })
      .catch((err) => {
        setError(err.message);
        setLoading(false);
      });
  }, []);

  // 当前展示的版本：选中的历史版本会覆盖顶层字段（保留 source/versions 等）
  const active = useMemo<BetaData | null>(() => {
    if (!data) return null;
    if (selectedVersion) {
      const item = data.versions?.find((v) => v.version === selectedVersion);
      if (item) return { ...data, ...item };
    }
    return data;
  }, [data, selectedVersion]);

  const isGithub = active?.source === "github";
  const hasAnyDownload = !!(
    active &&
    PLATFORM_SLOTS.some((k) => active.app[k].DownlodeURL)
  );

  const formatDate = (d?: string) =>
    d ? new Date(d).toLocaleDateString("zh-CN") : "未知";

  /** 跳转感谢下载页（携带 链接/平台/SHA512/加速类型），由该页自动下载 */
  const goThanks = (url: string, os: DownloadOsKey) => {
    router.push(
      buildDownloadThanksUrl({
        url,
        os,
        source: downloadSource,
        version: active?.version,
      })
    );
  };

  const handleDownload = (platform: PlatformInfo, os: DownloadOsKey) => {
    if (!platform.DownlodeURL) return;
    const url = resolveDownloadUrl(downloadSource, platform.DownlodeURL);
    if (platform.licence.isNeedAgreat === "true") {
      setActivePlatform(platform);
      setPendingOs(os);
      setDialogOpen(true);
    } else {
      goThanks(url, os);
    }
  };

  const confirmDownload = () => {
    if (activePlatform?.DownlodeURL) {
      goThanks(
        resolveDownloadUrl(downloadSource, activePlatform.DownlodeURL),
        pendingOs
      );
    }
    setDialogOpen(false);
    setActivePlatform(null);
  };

  if (loading) {
    return (
      <div className="flex flex-col items-center justify-center min-h-[60vh] gap-4">
        <Loader2 className="size-8 animate-spin text-muted-foreground" />
        <p className="text-muted-foreground">正在获取版本信息...</p>
      </div>
    );
  }

  if (error || !data) {
    return (
      <div className="flex flex-col items-center justify-center min-h-[60vh] gap-4">
        <AlertCircle className="size-8 text-destructive" />
        <p className="text-muted-foreground">获取版本信息失败</p>
        <Button variant="outline" onClick={() => window.location.reload()}>
          重试
        </Button>
      </div>
    );
  }

  if (data.noRelease) {
    return (
      <div className="flex flex-col items-center justify-center min-h-[60vh] gap-4 text-center px-4">
        <PackageOpen className="size-10 text-muted-foreground" />
        <div>
          <p className="font-semibold text-lg">暂无预览版本</p>
          <p className="text-sm text-muted-foreground max-w-sm mt-1">
            GitHub Releases 中暂时没有可用的预览（Beta）版本，请稍后再来看看
          </p>
        </div>
        <a
          href="https://github.com/dream-pep/koring-launcher/releases"
          target="_blank"
          rel="noopener noreferrer"
        >
          <Button variant="outline">
            前往 GitHub Releases
            <ArrowUpRight className="size-4" />
          </Button>
        </a>
      </div>
    );
  }

  if (!active) return null;

  return (
    <div className="flex flex-col w-full h-full gap-10 pb-24">
      {/* Header */}
      <div className="flex flex-col gap-2">
        <Badge variant="outline" className="w-fit">
          加入 Beta 测试
        </Badge>
        <h1 className="text-3xl md:text-5xl font-bold tracking-tight">
          Koring Launcher
        </h1>
        <p className="text-muted-foreground text-base md:text-lg max-w-xl">
          参与 Koring Launcher 的 Beta 测试计划，抢先体验最新功能
        </p>
        <div className="flex flex-wrap items-center gap-x-3 gap-y-1 text-xs text-muted-foreground">
          {isGithub ? (
            <>
              <span className="flex items-center gap-1">
                <GitBranch className="size-3" />
                版本信息由 GitHub Releases 自动识别
              </span>
              {active.htmlUrl && (
                <a
                  href={active.htmlUrl}
                  target="_blank"
                  rel="noopener noreferrer"
                  className="flex items-center gap-1 text-primary underline underline-offset-3 hover:text-primary/80"
                >
                  在 GitHub 查看发布页
                  <ArrowUpRight className="size-3" />
                </a>
              )}
            </>
          ) : (
            <span className="flex items-center gap-1">
              <GitBranch className="size-3" />
              版本信息来自缓存数据源
            </span>
          )}
        </div>
      </div>

      {/* Version Info Card */}
      <div className="rounded-2xl border border-border/50 p-6 bg-background/60 backdrop-blur-xl flex flex-col sm:flex-row gap-6">
        <div className="flex items-center gap-3">
          <div className="flex items-center justify-center w-10 h-10 rounded-xl bg-primary/10">
            <Package className="size-5 text-primary" />
          </div>
          <div>
            <p className="text-xs text-muted-foreground">版本号</p>
            <p className="font-semibold text-lg">{active.version}</p>
          </div>
        </div>
        <div className="flex items-center gap-3">
          <div className="flex items-center justify-center w-10 h-10 rounded-xl bg-primary/10">
            {isGithub ? (
              <Calendar className="size-5 text-primary" />
            ) : (
              <Hash className="size-5 text-primary" />
            )}
          </div>
          <div>
            <p className="text-xs text-muted-foreground">
              {isGithub ? "发布时间" : "编译号"}
            </p>
            <p className="font-semibold text-lg">
              {isGithub ? formatDate(active.builddate) : active.builddate}
            </p>
          </div>
        </div>
      </div>

      {/* 历史版本选择 */}
      {data.versions && data.versions.length > 0 && (
        <label className="flex items-center gap-2 text-sm text-muted-foreground">
          <History className="size-4 shrink-0" />
          <span className="shrink-0">选择版本</span>
          <select
            value={selectedVersion ?? ""}
            onChange={(e) => setSelectedVersion(e.target.value || null)}
            className="max-w-[16rem] rounded-lg border border-border bg-background px-3 py-2 text-sm text-foreground outline-none transition-colors focus:border-primary"
          >
            <option value="">最新版本 {data.version}</option>
            {data.versions.map((v) => (
              <option key={v.version} value={v.version}>
                {v.version}
                {" · "}
                {formatDate(v.builddate)}
              </option>
            ))}
          </select>
        </label>
      )}

      {/* Platform Cards */}
      <div>
        <div className="flex flex-col sm:flex-row sm:items-center justify-between gap-3 mb-4">
          <h2 className="text-xl font-semibold">选择平台</h2>
          {isGithub && hasAnyDownload && (
            <div className="flex items-center gap-2 flex-wrap">
              <span className="text-xs text-muted-foreground">下载源</span>
              {DOWNLOAD_SOURCES.map((s) => (
                <button
                  key={s.key}
                  type="button"
                  onClick={() => setDownloadSource(s.key)}
                  className={cn(
                    "rounded-full border px-3 py-1 text-xs transition-colors",
                    downloadSource === s.key
                      ? "border-primary bg-primary/10 text-primary"
                      : "border-border text-muted-foreground hover:text-foreground"
                  )}
                >
                  {s.label}
                </button>
              ))}
            </div>
          )}
        </div>
        <PlatformDownloadGrid
          platforms={[
            {
              key: "windows",
              label: "Windows",
              icon: Monitor,
              download: active.app.windows.DownlodeURL
                ? { url: active.app.windows.DownlodeURL }
                : null,
              hint: "未提供对应版本",
            },
            {
              key: "macos",
              label: "macOS",
              icon: Apple,
              download: active.app.macos.DownlodeURL
                ? { url: active.app.macos.DownlodeURL }
                : null,
              hint: "未提供对应版本",
            },
            {
              key: "linux",
              label: "Linux",
              icon: Terminal,
              download: active.app.linux.DownlodeURL
                ? { url: active.app.linux.DownlodeURL }
                : null,
              hint: "未提供对应版本",
            },
          ]}
          onDownload={(slot) => {
            const info = active.app[slot.key as keyof AppInfo];
            if (info?.DownlodeURL) handleDownload(info, slot.key as DownloadOsKey);
          }}
        />
      </div>

      {/* Release Notes / About This Version */}
      <div className="rounded-2xl border border-border/50 p-6 md:p-8 bg-background/60 backdrop-blur-xl">
        <div className="flex items-center gap-2 mb-4">
          <FileText className="size-5 text-primary" />
          <h2 className="text-xl font-semibold">
            {active.releaseNotes ? "版本更新内容" : "关于此版本"}
          </h2>
        </div>
        {active.releaseNotes ? (
          <ReleaseNotes text={active.releaseNotes} />
        ) : active.aboutversion ? (
          <>
            <p className="text-muted-foreground leading-relaxed mb-4">
              {active.aboutversion.about}
            </p>
            <ul className="flex flex-col gap-2">
              {Object.entries(active.aboutversion["about-list"]).map(
                ([key, text]) => (
                  <li key={key} className="flex items-start gap-2 text-sm">
                    <span className="mt-1.5 size-1.5 rounded-full bg-primary shrink-0" />
                    <span className="text-muted-foreground">{text}</span>
                  </li>
                )
              )}
            </ul>
          </>
        ) : null}
      </div>

      {/* License Dialog */}
      <Dialog open={dialogOpen} onOpenChange={setDialogOpen}>
        <DialogContent className="sm:max-w-md">
          <DialogHeader>
            <DialogTitle>{activePlatform?.licence.title}</DialogTitle>
            <DialogDescription className="text-sm leading-relaxed whitespace-pre-line mt-2">
              {activePlatform?.licence.text}
            </DialogDescription>
          </DialogHeader>
          {activePlatform?.licence.liceURL && (
            <a
              href={activePlatform.licence.liceURL}
              target="_blank"
              rel="noopener noreferrer"
              className="text-sm text-primary underline underline-offset-3 hover:text-primary/80 flex items-center gap-1 w-fit"
            >
              <ArrowUpRight className="size-3.5" />
              查看《Koring APP Beta 测试协议》
            </a>
          )}
          <DialogFooter>
            <Button variant="outline" onClick={() => setDialogOpen(false)}>
              取消
            </Button>
            <Button onClick={confirmDownload}>
              <ArrowUpRight className="size-4" />
              同意并下载
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  );
}