import { useEffect, useMemo, useRef, useState } from "react";
import { api, AppInfo, ModelInfo } from "../api";
import { useStore } from "../store";

export default function SettingsPage() {
  const [info, setInfo] = useState<AppInfo | null>(null);
  const [settings, setSettings] = useState<Record<string, string>>({});
  const [recommendDirDraft, setRecommendDirDraft] = useState("");
  const [uploadMsg, setUploadMsg] = useState<string | null>(null);
  const [startupMsg, setStartupMsg] = useState<string | null>(null);
  const [autostart, setAutostart] = useState<boolean | null>(null);
  const [autoLoadDraft, setAutoLoadDraft] = useState<string[]>([]);
  const [pickId, setPickId] = useState("");
  const uploadInputRef = useRef<HTMLInputElement>(null);
  const models = useStore((s) => s.models);
  const refreshModels = useStore((s) => s.refreshModels);

  useEffect(() => {
    api.appInfo().then(setInfo);
    api.settingsGet().then(setSettings);
    api.autostartStatus().then(setAutostart).catch(() => setAutostart(false));
    refreshModels();
  }, []);

  useEffect(() => {
    setRecommendDirDraft(settings.recommend_dir ?? "");
  }, [settings.recommend_dir]);

  useEffect(() => {
    try {
      const parsed = JSON.parse(settings.auto_load_models ?? "[]");
      setAutoLoadDraft(Array.isArray(parsed) ? parsed : []);
    } catch {
      setAutoLoadDraft([]);
    }
  }, [settings.auto_load_models]);

  async function handleSave(key: string, value: string) {
    await api.settingsSet(key, value);
    setSettings((prev) => ({ ...prev, [key]: value }));
  }

  async function handleAutostartToggle(checked: boolean) {
    try {
      setAutostart(await api.autostartSet(checked));
      setStartupMsg(checked ? "已开启开机启动" : "已关闭开机启动");
    } catch (e) {
      setStartupMsg(`开机启动设置失败：${String(e)}`);
    }
  }

  const localModels = useMemo(
    () => models.filter((m) => m.kind === "local"),
    [models],
  );
  const draftRows = useMemo(
    () =>
      autoLoadDraft
        .map((id) => localModels.find((m) => m.id === id))
        .filter((m): m is ModelInfo => Boolean(m)),
    [autoLoadDraft, localModels],
  );
  const available = useMemo(
    () => localModels.filter((m) => !autoLoadDraft.includes(m.id)),
    [localModels, autoLoadDraft],
  );

  function moveRow(index: number, dir: -1 | 1) {
    setAutoLoadDraft((prev) => {
      const next = [...prev];
      const target = index + dir;
      if (target < 0 || target >= next.length) return prev;
      [next[index], next[target]] = [next[target], next[index]];
      return next;
    });
  }

  function removeRow(index: number) {
    setAutoLoadDraft((prev) => prev.filter((_, i) => i !== index));
  }

  async function handleSaveAutoLoad() {
    await handleSave("auto_load_models", JSON.stringify(draftRows.map((m) => m.id)));
  }

  function modelDisplayName(m: ModelInfo) {
    return m.file_name.replace(/\.gguf$/i, "");
  }

  async function handleUpload(file: File) {
    setUploadMsg(null);
    try {
      const text = await file.text();
      await api.importRecommendations(file.name, text);
      setUploadMsg(`已导入 ${file.name}`);
    } catch (e) {
      setUploadMsg(String(e));
    } finally {
      if (uploadInputRef.current) uploadInputRef.current.value = "";
    }
  }

  return (
    <div className="h-full overflow-auto p-6">
      <h1 className="text-xl font-semibold">设置</h1>
      <p className="mt-1 text-sm text-slate-400">运行路径与引擎配置</p>

      <div className="mt-6 max-w-xl space-y-4">
        <div className="rounded-xl border border-border bg-panel p-5">
          <div className="text-xs uppercase text-slate-400">关于</div>
          <div className="mt-2 space-y-1 text-sm">
            <div>
              版本：<span className="text-slate-300">{info?.version}</span>（{info?.platform}）
            </div>
            <div>
              数据目录：<span className="text-slate-300">{info?.db_path}</span>
            </div>
            <div className="flex items-center gap-2">
              <span>
                日志目录：<span className="text-slate-300">{info?.logs_dir}</span>
              </span>
              {info?.logs_dir ? (
                <button
                  className="text-xs text-slate-400 hover:text-slate-200"
                  onClick={() => api.openPath(info.logs_dir!)}
                >
                  打开
                </button>
              ) : null}
            </div>
            <div>
              引擎可用：
              {info?.engine_exists ? (
                <span className="text-emerald-400">是</span>
              ) : (
                <span className="text-red-400">否（请配置 llama-server 路径）</span>
              )}
            </div>
          </div>
        </div>

        <div className="rounded-xl border border-border bg-panel p-5">
          <div className="text-xs uppercase text-slate-400">引擎与路径</div>
          <div className="mt-3 space-y-3">
            <SettingInput
              label="模型目录"
              value={settings.model_dir ?? ""}
              onSave={(v) => handleSave("model_dir", v)}
            />
            <SettingInput
              label="llama-server 路径（llama-server-cpu/cuda/vulkan.exe）"
              value={settings.engine_bin ?? ""}
              onSave={(v) => handleSave("engine_bin", v)}
            />
            <SettingInput
              label="模型下载源（hf-mirror.com / huggingface.co / modelscope.cn）"
              value={settings.hf_endpoint ?? ""}
              onSave={(v) => handleSave("hf_endpoint", v)}
            />
            <SettingInput
              label="默认后端（auto / cpu / cuda / vulkan）"
              value={settings.backend ?? ""}
              onSave={(v) => handleSave("backend", v)}
            />
            <SettingInput
              label="上传图片/文件大小上限（MB）"
              value={settings.upload_max_mb ?? "10"}
              onSave={(v) => handleSave("upload_max_mb", v)}
            />
          </div>
        </div>

        <div className="rounded-xl border border-border bg-panel p-5">
          <div className="text-xs uppercase text-slate-400">启动</div>
          {startupMsg ? (
            <div className="mt-2 text-xs text-slate-400">{startupMsg}</div>
          ) : null}
          <div className="mt-3 flex items-center justify-between rounded-lg border border-border bg-panel-2 px-3 py-2.5">
            <div>
              <div className="text-sm">开机启动</div>
              <div className="mt-0.5 text-xs text-slate-400">
                登录 Windows 后自动启动仙人工作室
              </div>
            </div>
            <Toggle
              checked={autostart === true}
              disabled={autostart === null}
              onChange={handleAutostartToggle}
            />
          </div>

          <div className="mt-4">
            <div className="text-sm">自动加载模型</div>
            <div className="mt-0.5 text-xs text-slate-400">
              应用启动后按列表顺序逐个加载本地模型；由于同一时间只能运行一个模型，全部加载完成后保留列表最后一个在运行
            </div>
            <div className="mt-3 space-y-2">
              {draftRows.length === 0 ? (
                <div className="rounded-lg border border-dashed border-border bg-panel-2/50 px-3 py-5 text-center text-xs text-slate-500">
                  还没有添加模型，从下方下拉框选择要自动加载的本地模型
                </div>
              ) : (
                draftRows.map((m, i) => (
                  <div
                    key={m.id}
                    className="flex items-center gap-2 rounded-lg border border-border bg-panel-2 px-3 py-2"
                  >
                    <span className="text-xs text-slate-500">{i + 1}</span>
                    <span className="min-w-0 flex-1 truncate text-sm">
                      {modelDisplayName(m)}
                    </span>
                    <button
                      className="rounded border border-border px-1.5 py-0.5 text-xs text-slate-400 hover:text-slate-200 disabled:opacity-40"
                      onClick={() => moveRow(i, -1)}
                      disabled={i === 0}
                      title="上移"
                    >
                      ↑
                    </button>
                    <button
                      className="rounded border border-border px-1.5 py-0.5 text-xs text-slate-400 hover:text-slate-200 disabled:opacity-40"
                      onClick={() => moveRow(i, 1)}
                      disabled={i === draftRows.length - 1}
                      title="下移"
                    >
                      ↓
                    </button>
                    <button
                      className="rounded border border-border px-1.5 py-0.5 text-xs text-slate-400 hover:text-red-400"
                      onClick={() => removeRow(i)}
                      title="移除"
                    >
                      ×
                    </button>
                  </div>
                ))
              )}
            </div>
            <div className="mt-3 flex items-center gap-2">
              <select
                className="input flex-1"
                value={pickId}
                onChange={(e) => setPickId(e.target.value)}
              >
                <option value="">
                  {available.length > 0
                    ? "选择要添加的本地模型…"
                    : "没有可添加的本地模型"}
                </option>
                {available.map((m) => (
                  <option key={m.id} value={m.id}>
                    {modelDisplayName(m)}
                  </option>
                ))}
              </select>
              <button
                className="btn-secondary shrink-0"
                disabled={!pickId}
                onClick={() => {
                  setAutoLoadDraft((prev) => [...prev, pickId]);
                  setPickId("");
                }}
              >
                添加
              </button>
            </div>
            <div className="mt-3 flex items-center justify-between gap-2">
              <span className="text-[11px] text-slate-500">
                列表顺序即加载顺序，可拖动上下按钮调整
              </span>
              <button
                className="btn-primary px-3 py-1.5 text-xs"
                onClick={handleSaveAutoLoad}
                disabled={
                  JSON.stringify(draftRows.map((m) => m.id)) ===
                  JSON.stringify(autoLoadDraft)
                }
              >
                保存列表
              </button>
            </div>
          </div>
        </div>

        <div className="rounded-xl border border-border bg-panel p-5">
          <div className="text-xs uppercase text-slate-400">对话</div>
          <div className="mt-3 flex items-center justify-between rounded-lg border border-border bg-panel-2 px-3 py-2.5">
            <div>
              <div className="text-sm">自动生成对话标题</div>
              <div className="mt-0.5 text-xs text-slate-400">
                首次对话生成回复后，自动为会话生成标题并覆盖
              </div>
            </div>
            <Toggle
              checked={settings.auto_title !== "false"}
              onChange={(checked) =>
                handleSave("auto_title", checked ? "true" : "false")
              }
            />
          </div>
          <div className="mt-3 flex items-center justify-between rounded-lg border border-border bg-panel-2 px-3 py-2.5">
            <div>
              <div className="text-sm">自动预测用户接下来说的话</div>
              <div className="mt-0.5 text-xs text-slate-400">
                大模型回答完成后自动预测几条用户可能要说的话，点击即可填入输入框
              </div>
            </div>
            <Toggle
              checked={settings.suggest_enabled !== "false"}
              onChange={(checked) =>
                handleSave("suggest_enabled", checked ? "true" : "false")
              }
            />
          </div>
          <div className="mt-3">
            <SettingInput
              label="预测条数（1-5）"
              value={settings.suggest_count ?? "3"}
              onSave={(v) => {
                const n = Math.max(1, Math.min(5, Number(v) || 3));
                handleSave("suggest_count", String(n));
              }}
            />
          </div>
        </div>

        <div className="rounded-xl border border-border bg-panel p-5">
          <div className="text-xs uppercase text-slate-400">推荐模型列表</div>
          <div className="mt-3 space-y-3">
            <div>
              <span className="text-xs text-slate-400">
                JSON 文件目录（软件自带默认列表，上传的 JSON 也会保存到这里）
              </span>
              <div className="mt-1 flex gap-2">
                <input
                  className="input flex-1"
                  value={recommendDirDraft}
                  onChange={(e) => setRecommendDirDraft(e.target.value)}
                />
                <button
                  className="btn-secondary"
                  onClick={() => handleSave("recommend_dir", recommendDirDraft)}
                  disabled={recommendDirDraft === settings.recommend_dir}
                >
                  保存
                </button>
                <button
                  className="btn-secondary"
                  onClick={() =>
                    recommendDirDraft && api.openPath(recommendDirDraft)
                  }
                >
                  打开
                </button>
              </div>
            </div>
            <div className="flex items-center gap-2">
              <input
                ref={uploadInputRef}
                type="file"
                accept=".json"
                className="hidden"
                onChange={(e) => {
                  if (e.target.files && e.target.files.length > 0) {
                    handleUpload(e.target.files[0]);
                  }
                }}
              />
              <button
                className="btn-secondary"
                onClick={() => uploadInputRef.current?.click()}
              >
                上传 JSON
              </button>
              <span className="text-xs text-slate-500">
                可上传多个推荐列表 JSON，同名文件将覆盖
              </span>
            </div>
            {uploadMsg ? (
              <div className="text-xs text-slate-400">{uploadMsg}</div>
            ) : null}
            <div className="text-xs text-slate-500">JSON 格式示例：</div>
            <pre className="mt-1 overflow-x-auto rounded-lg bg-panel-2 p-2 text-[11px] leading-relaxed text-slate-400">
              {`{
  "models": [
    {
      "id": "Qwen/Qwen2.5-7B-Instruct-GGUF",
      "source": "huggingface",
      "params": "7B",
      "architecture": "dense",
      "vision": false,
      "files": [
        {
          "path": "xx-q4_k_m.gguf",
          "quant": "Q4_K_M",
          "size_gb": 4.68,
          "links": [
            "https://hf-mirror.com/Qwen/Qwen2.5-7B-Instruct-GGUF/resolve/main/xx-q4_k_m.gguf",
            "https://modelscope.cn/models/Qwen/Qwen2.5-7B-Instruct-GGUF/resolve/master/xx-q4_k_m.gguf"
          ]
        }
      ]
    }
  ]
}`}
            </pre>
          </div>
        </div>

        <div className="text-xs text-slate-500">
          获取 llama-server：运行 <code className="text-slate-300">scripts/fetch-llama.ps1</code>{" "}
          自动下载预编译引擎，或手动指定已下载的 exe 路径。
        </div>
      </div>
    </div>
  );
}

function Toggle({
  checked,
  onChange,
  disabled = false,
}: {
  checked: boolean;
  onChange: (checked: boolean) => void;
  disabled?: boolean;
}) {
  return (
    <button
      type="button"
      role="switch"
      aria-checked={checked}
      disabled={disabled}
      onClick={() => onChange(!checked)}
      className={`relative h-6 w-11 shrink-0 rounded-full transition-colors ${
        checked ? "bg-accent" : "bg-panel-2"
      } ${disabled ? "cursor-not-allowed opacity-50" : ""}`}
    >
      <span
        className={`absolute top-0.5 h-5 w-5 rounded-full bg-white shadow transition-all ${
          checked ? "left-[22px]" : "left-0.5"
        }`}
      />
    </button>
  );
}

function SettingInput({
  label,
  value,
  onSave,
}: {
  label: string;
  value: string;
  onSave: (v: string) => void;
}) {
  const [draft, setDraft] = useState(value);
  useEffect(() => setDraft(value), [value]);
  return (
    <label className="block text-sm">
      <span className="text-xs text-slate-400">{label}</span>
      <div className="mt-1 flex gap-2">
        <input className="input flex-1" value={draft} onChange={(e) => setDraft(e.target.value)} />
        <button
          className="btn-secondary"
          onClick={() => onSave(draft)}
          disabled={draft === value}
        >
          保存
        </button>
      </div>
    </label>
  );
}