import {
  type GlobalSettings,
  GlobalSettings as GlobalSettingsSchema,
  type GlobalSettingsUpdate,
  mergeSettings,
} from "@umt/contracts";
import { LoaderCircle } from "lucide-react";
import { type ReactNode, useState } from "react";
import { toast } from "sonner";
import { useSettings, useUpdateSettings } from "~/api/settings.ts";
import { ErrorState, LoadingState } from "~/components/console/empty-state.tsx";
import { zodFieldErrors } from "~/components/console/form-field.tsx";
import { Button } from "~/components/ui/button.tsx";
import { Label } from "~/components/ui/label.tsx";
import { errorMessage } from "~/lib/api.ts";
import { revealFirstError } from "~/lib/form-errors.ts";
import { cn } from "~/lib/utils.ts";
import {
  FieldInput,
  type FieldSpec,
  type FieldValue,
  type FormValues,
  fieldHint,
  localFieldErrors,
} from "./resource-section.tsx";
import { SaveBar, SettingsBlock } from "./settings-block.tsx";

// 全局设置的一节:一组字段,独立保存(PATCH 对应 key);
// 校验 = 合并现值后用 contracts GlobalSettings 整体校验(含"恢复水位 < 硬阈值"等交叉规则)。

export type CardSpec = {
  /** 锚点 id(分区内唯一) */
  anchor: string;
  title: string;
  description?: ReactNode;
  fields: FieldSpec[];
  fromSettings: (s: GlobalSettings) => FormValues;
  toPatch: (v: FormValues, s: GlobalSettings) => GlobalSettingsUpdate;
  extra?: (s: GlobalSettings) => ReactNode;
};

export function SettingsCard({
  spec,
  settings,
  section,
}: {
  spec: CardSpec;
  settings: GlobalSettings;
  section: string;
}) {
  const update = useUpdateSettings();
  const [values, setValues] = useState<FormValues>(() => spec.fromSettings(settings));
  const [errors, setErrors] = useState<Record<string, string>>({});
  const initial = spec.fromSettings(settings);
  const dirty = Object.keys(values).some((k) => values[k] !== initial[k]);

  const save = async (e: React.FormEvent) => {
    e.preventDefault();
    const local = localFieldErrors(spec.fields, values);
    if (Object.keys(local).length) {
      setErrors(local);
      revealFirstError();
      return;
    }
    const patch = spec.toPatch(values, settings);
    const parsed = GlobalSettingsSchema.safeParse(mergeSettings(settings, patch));
    if (!parsed.success) {
      const fe = zodFieldErrors(parsed.error.issues);
      // 交叉校验(refine)落在分组上:挂到本节同组的第一个字段
      for (const [k, m] of Object.entries(fe)) {
        if (!spec.fields.some((f) => f.name === k))
          fe[spec.fields.find((f) => k.startsWith(f.name.split(".")[0] ?? ""))?.name ?? k] ??= m;
      }
      setErrors(fe);
      revealFirstError();
      return;
    }
    setErrors({});
    try {
      const next = await update.mutateAsync(patch);
      setValues(spec.fromSettings(next));
      toast.success(`已保存「${spec.title}」`);
    } catch (err) {
      toast.error(errorMessage(err, "保存失败"));
    }
  };

  return (
    <SettingsBlock
      section={section}
      anchor={spec.anchor}
      title={spec.title}
      description={spec.description}
      dirty={dirty}
    >
      <form onSubmit={save} noValidate>
        <div className="divide-y divide-border/60">
          {spec.fields
            .filter((f) => !f.visible || f.visible(values))
            .map((f) => (
              <SettingsField
                key={f.name}
                spec={f}
                value={values[f.name]}
                values={values}
                error={errors[f.name]}
                disabled={update.isPending}
                onChange={(v) => setValues((s) => ({ ...s, [f.name]: v }))}
              />
            ))}
        </div>
        {spec.extra ? <div className="mt-4">{spec.extra(settings)}</div> : null}
        <SaveBar dirty={dirty}>
          {dirty ? (
            <Button
              type="button"
              variant="ghost"
              size="sm"
              onClick={() => {
                setValues(spec.fromSettings(settings));
                setErrors({});
              }}
            >
              还原
            </Button>
          ) : null}
          <Button type="submit" size="sm" disabled={update.isPending || !dirty}>
            {update.isPending ? <LoaderCircle className="animate-spin" /> : null}
            保存
          </Button>
        </SaveBar>
      </form>
    </SettingsBlock>
  );
}

/** 控件宽度按类型固定:数字短、选择与单行文本中等、wide/多行占满 */
function controlWidth(spec: FieldSpec): string {
  if (spec.kind === "switch") return "";
  if (spec.wide || spec.kind === "textarea") return "w-full";
  if (spec.kind === "number" || spec.kind === "tokens") return "w-full sm:w-40";
  if (spec.kind === "select") return "w-full sm:max-w-xs";
  return "w-full sm:max-w-md";
}

/**
 * 设置表单的一行:标签与说明在左,控件在右;md 以下上下堆叠(开关仍与标签同行)。
 * 错误写在控件下方,说明留在标签下,行高不因出错跳动以外的原因变化。
 */
export function SettingsField({
  spec,
  value,
  error,
  onChange,
  disabled,
  values,
}: {
  spec: FieldSpec;
  value: FieldValue | undefined;
  error?: string;
  onChange: (v: FieldValue) => void;
  disabled?: boolean;
  /** 整个表单的值(凭证字段据此判断是否已设置) */
  values?: FormValues;
}) {
  const id = `f-${spec.name}`;
  const isSwitch = spec.kind === "switch";
  const hint = fieldHint(spec, value, values ?? {}, spec.hint);
  return (
    <div
      className={cn(
        "grid gap-x-6 gap-y-2 py-4 first:pt-0 last:pb-0 md:grid-cols-[minmax(0,15rem)_minmax(0,1fr)]",
        isSwitch && "grid-cols-[minmax(0,1fr)_auto] items-start",
      )}
    >
      <div className={cn("min-w-0", !isSwitch && "md:pt-2")}>
        <Label htmlFor={id} className="text-caption font-medium text-foreground">
          {spec.label}
          {spec.required ? <span className="text-destructive">*</span> : null}
        </Label>
        {hint ? <p className="mt-1 text-meta text-muted-foreground">{hint}</p> : null}
      </div>
      <div className={cn("min-w-0", isSwitch && "pt-0.5 md:justify-self-start")}>
        <FieldInput
          id={id}
          spec={spec}
          value={value}
          values={values}
          error={error}
          onChange={onChange}
          disabled={disabled}
          className={controlWidth(spec)}
        />
        {error ? (
          <p className="mt-1.5 text-meta text-destructive" role="alert">
            {error}
          </p>
        ) : null}
      </div>
    </div>
  );
}

/** 读取全局设置后再渲染(加载 / 出错占位) */
export function SettingsGate({ children }: { children: (s: GlobalSettings) => ReactNode }) {
  const q = useSettings();
  if (q.isPending) return <LoadingState rows={6} />;
  if (q.isError) return <ErrorState error={q.error} onRetry={() => q.refetch()} />;
  return <>{children(q.data)}</>;
}

/** 数字 → 表单字符串(null 为空) */
export const n = (v: number | null | undefined) => (v === null || v === undefined ? "" : String(v));