"use client";

import { ImagePlus, Images, X } from "lucide-react";
import { useEffect, useRef, useState, type Dispatch, type SetStateAction } from "react";
import {
  AdminSegmented,
  AdminSettingsActions,
  AdminSettingsGroup,
  AdminSettingsRow,
} from "@/components/admin";
import BrandLockup from "@/components/BrandLockup";
import { apiBrandFromMedia, apiUpdateSiteSettings, apiUploadBrand, type PublicSettings } from "@/lib/api";
import {
  BRAND_LOGO_FITS,
  BRAND_LOGO_SIZES,
  brandAccept,
  brandFileOk,
  type BrandLogoFit,
  type BrandLogoSize,
  type BrandMark,
  type BrandSlot,
} from "@/lib/brand";
import { toast } from "@/lib/toast";
import BrandMediaPicker from "./BrandMediaPicker";

type SlotDraft = {
  committed: string;
  file: File | null;
  blob: string;
  mediaId: number | null;
  mediaUrl: string;
};

function emptyDraft(committed: string): SlotDraft {
  return { committed, file: null, blob: "", mediaId: null, mediaUrl: "" };
}

function previewOf(d: SlotDraft): string {
  return d.blob || d.mediaUrl || d.committed;
}

function slotDirty(d: SlotDraft, saved: string): boolean {
  if (d.file || d.mediaId != null) return true;
  return d.committed !== saved;
}

const SLOTS: { id: BrandSlot; label: string; hint: string; swatch: "light" | "dark" | "neutral" }[] = [
  { id: "logo_light", label: "浅色主题 Logo", hint: "浅色主题页眉。只传一套时，暗色共用这张。", swatch: "light" },
  { id: "logo_dark", label: "深色主题 Logo", hint: "深色主题页眉。PNG / WebP / SVG，不超过 2MB。", swatch: "dark" },
  { id: "favicon", label: "Favicon", hint: "浏览器标签图标。另支持 ICO，不超过 512KB。", swatch: "neutral" },
];

export default function BrandSeoPanel({
  initial,
  onSaved,
  onDirtyChange,
}: {
  initial: PublicSettings;
  onSaved?: (next: PublicSettings) => void;
  onDirtyChange?: (dirty: boolean) => void;
}) {
  const [light, setLight] = useState<SlotDraft>(() => emptyDraft(initial.logo_light_url));
  const [dark, setDark] = useState<SlotDraft>(() => emptyDraft(initial.logo_dark_url));
  const [favicon, setFavicon] = useState<SlotDraft>(() => emptyDraft(initial.favicon_url));
  const [saved, setSaved] = useState({
    light: initial.logo_light_url,
    dark: initial.logo_dark_url,
    favicon: initial.favicon_url,
    mark: initial.brand_mark,
    size: initial.brand_logo_size,
    fit: initial.brand_logo_fit,
  });
  const [mark, setMark] = useState<BrandMark>(initial.brand_mark);
  const [logoSize, setLogoSize] = useState<BrandLogoSize>(initial.brand_logo_size);
  const [logoFit, setLogoFit] = useState<BrandLogoFit>(initial.brand_logo_fit);
  const [saving, setSaving] = useState(false);
  const [saveError, setSaveError] = useState("");
  const [picker, setPicker] = useState<BrandSlot | null>(null);
  const blobs = useRef<string[]>([]);
  const saveGen = useRef(0);

  useEffect(() => {
    const held = blobs;
    return () => {
      held.current.forEach((u) => URL.revokeObjectURL(u));
    };
  }, []);

  const drafts: Record<BrandSlot, [SlotDraft, Dispatch<SetStateAction<SlotDraft>>]> = {
    logo_light: [light, setLight],
    logo_dark: [dark, setDark],
    favicon: [favicon, setFavicon],
  };

  const replaceFile = (slot: BrandSlot, file: File | null) => {
    setSaveError("");
    const [, set] = drafts[slot];
    set((prev) => {
      if (prev.blob) URL.revokeObjectURL(prev.blob);
      const blob = file ? URL.createObjectURL(file) : "";
      if (blob) blobs.current.push(blob);
      return { ...prev, file, blob, mediaId: null, mediaUrl: "" };
    });
  };

  const dirty =
    slotDirty(light, saved.light) ||
    slotDirty(dark, saved.dark) ||
    slotDirty(favicon, saved.favicon) ||
    mark !== saved.mark ||
    logoSize !== saved.size ||
    logoFit !== saved.fit;

  useEffect(() => {
    onDirtyChange?.(dirty);
  }, [dirty, onDirtyChange]);

  const resolveSlot = async (slot: BrandSlot, draft: SlotDraft): Promise<string> => {
    if (draft.file) {
      const url = await apiUploadBrand(slot, draft.file);
      return url;
    }
    if (draft.mediaId != null) {
      return apiBrandFromMedia(slot, draft.mediaId);
    }
    return draft.committed;
  };

  const discard = () => {
    [light, dark, favicon].forEach((d) => {
      if (d.blob) URL.revokeObjectURL(d.blob);
    });
    setLight(emptyDraft(saved.light));
    setDark(emptyDraft(saved.dark));
    setFavicon(emptyDraft(saved.favicon));
    setMark(saved.mark);
    setLogoSize(saved.size);
    setLogoFit(saved.fit);
    setSaveError("");
  };

  const save = async () => {
    if (saving || !dirty) return;
    const ticket = ++saveGen.current;
    const snap = {
      mark,
      size: logoSize,
      fit: logoFit,
    };
    setSaving(true);
    setSaveError("");
    try {
      const logoLight = await resolveSlot("logo_light", light);
      const logoDark = await resolveSlot("logo_dark", dark);
      const fav = await resolveSlot("favicon", favicon);
      const res = await apiUpdateSiteSettings({
        logo_light_url: logoLight,
        logo_dark_url: logoDark,
        favicon_url: fav,
        brand_mark: mark,
        brand_logo_size: logoSize,
        brand_logo_fit: logoFit,
      });
      if (ticket !== saveGen.current) return;
      setSaved({
        light: res.logo_light_url,
        dark: res.logo_dark_url,
        favicon: res.favicon_url,
        mark: res.brand_mark,
        size: res.brand_logo_size,
        fit: res.brand_logo_fit,
      });
      setMark((v) => (v === snap.mark ? res.brand_mark : v));
      setLogoSize((v) => (v === snap.size ? res.brand_logo_size : v));
      setLogoFit((v) => (v === snap.fit ? res.brand_logo_fit : v));
      setLight((cur) => {
        if (cur.file === light.file && cur.mediaId === light.mediaId && cur.committed === light.committed) {
          if (cur.blob) URL.revokeObjectURL(cur.blob);
          return emptyDraft(res.logo_light_url);
        }
        return cur;
      });
      setDark((cur) => {
        if (cur.file === dark.file && cur.mediaId === dark.mediaId && cur.committed === dark.committed) {
          if (cur.blob) URL.revokeObjectURL(cur.blob);
          return emptyDraft(res.logo_dark_url);
        }
        return cur;
      });
      setFavicon((cur) => {
        if (cur.file === favicon.file && cur.mediaId === favicon.mediaId && cur.committed === favicon.committed) {
          if (cur.blob) URL.revokeObjectURL(cur.blob);
          return emptyDraft(res.favicon_url);
        }
        return cur;
      });
      onSaved?.(res);
      toast("品牌设置已保存", "ok");
    } catch (e) {
      if (ticket !== saveGen.current) return;
      const msg = e instanceof Error ? e.message : "保存失败";
      setSaveError(msg);
      toast(msg);
    } finally {
      if (ticket === saveGen.current) setSaving(false);
    }
  };

  const renderSlot = (slot: BrandSlot, label: string, hint: string, swatch: "light" | "dark" | "neutral", draft: SlotDraft) => {
    const preview = previewOf(draft);
    const swatchClass =
      swatch === "light"
        ? "admin-brand-swatch-light"
        : swatch === "dark"
          ? "admin-brand-swatch-dark"
          : "admin-brand-swatch-neutral";
    return (
      <div key={slot} className="admin-brand-slot-card">
        <p className="text-[13px] font-medium" style={{ color: "var(--ink)" }}>
          {label}
        </p>
        <p className="meta text-[12px] mt-0.5 mb-2">{hint}</p>
        <div className={`admin-brand-swatch ${swatchClass}`}>
          {preview ? (
            // eslint-disable-next-line @next/next/no-img-element
            <img src={preview} alt={`${label}预览`} />
          ) : (
            <span className="text-[12.5px]">未设置</span>
          )}
        </div>
        <div className="flex flex-wrap gap-1.5 mt-2">
          <label className="btn btn-line btn-sm cursor-pointer">
            <ImagePlus size={14} /> 上传
            <input
              type="file"
              accept={brandAccept(slot)}
              className="hidden"
              aria-label={`上传${label}`}
              disabled={saving}
              onChange={(e) => {
                const file = e.target.files?.[0];
                e.target.value = "";
                if (!file) return;
                const err = brandFileOk(slot, file);
                if (err) {
                  toast(err);
                  return;
                }
                replaceFile(slot, file);
              }}
            />
          </label>
          <button type="button" className="btn btn-line btn-sm" disabled={saving} onClick={() => setPicker(slot)}>
            <Images size={14} /> 媒体库
          </button>
          <button
            type="button"
            className="btn btn-line btn-sm"
            disabled={saving || !preview}
            onClick={() => {
              if (draft.blob) URL.revokeObjectURL(draft.blob);
              drafts[slot][1](emptyDraft(""));
            }}
          >
            <X size={14} /> 清除
          </button>
        </div>
      </div>
    );
  };

  return (
    <AdminSettingsGroup
      title="品牌与图标"
      description="预览随编辑更新，保存后对访客生效。"
      footer={
        <AdminSettingsActions
          dirty={dirty}
          saving={saving}
          saveLabel="保存品牌设置"
          error={saveError}
          onSave={() => void save()}
          onDiscard={discard}
        />
      }
    >
      <AdminSettingsRow label="页眉形式" hintBelow="图加文字和纯图共用画幅与铺法">
        <AdminSegmented
          role="group"
          size="sm"
          ariaLabel="页眉形式"
          value={mark}
          onChange={(v) => {
            setMark(v);
            if (saveError) setSaveError("");
          }}
          options={[
            { key: "image_text", label: "图加文字" },
            { key: "image", label: "纯图" },
            { key: "text", label: "纯文字" },
          ]}
        />
      </AdminSettingsRow>
      <AdminSettingsRow
        label="品牌预览"
        hintBelow={dirty ? "页眉效果预览；站点仍显示已保存版本，保存后对访客生效" : "页眉效果预览，保存后对访客生效"}
      >
        <div className="admin-brand-lockup-preview">
          <div className="admin-brand-lockup-preview-bar">
            <BrandLockup
              mode={mark}
              size={logoSize}
              fit={logoFit}
              frame
              name={initial.site_name}
              wordmark={initial.site_wordmark}
              slogan={initial.site_slogan}
              logoLight={previewOf(light)}
              logoDark={previewOf(dark)}
            />
          </div>
        </div>
      </AdminSettingsRow>
      {mark !== "text" ? (
        <>
          <AdminSettingsRow label="Logo 比例">
            <div className="flex flex-wrap gap-2" role="group" aria-label="Logo 比例">
              {BRAND_LOGO_SIZES.map((item) => {
                const on = logoSize === item.id;
                const thumbH = 16;
                const thumbW = Math.round((item.w / item.h) * thumbH);
                return (
                  <button
                    key={item.id}
                    type="button"
                    className="rounded-xl px-3 py-2 text-left inline-flex items-center gap-2"
                    style={{
                      background: on ? "var(--accent-soft)" : "var(--panel)",
                      color: on ? "var(--accent)" : "var(--ink)",
                      boxShadow: on ? "inset 0 0 0 1px var(--accent)" : "inset 0 0 0 1px var(--line)",
                    }}
                    onClick={() => {
                      setLogoSize(item.id);
                      if (saveError) setSaveError("");
                    }}
                  >
                    <span
                      aria-hidden
                      className="shrink-0 rounded-sm"
                      style={{
                        width: thumbW,
                        height: thumbH,
                        boxShadow: "inset 0 0 0 1.5px currentColor",
                      }}
                    />
                    <span>
                      <span className="block text-[13px] font-medium">{item.label}</span>
                      <span className="meta text-[12px]">
                        {item.w}×{item.h}
                      </span>
                    </span>
                  </button>
                );
              })}
            </div>
          </AdminSettingsRow>
          <AdminSettingsRow label="适配方式" hintBelow="图片如何铺进所选画幅">
            <AdminSegmented
              role="group"
              size="sm"
              ariaLabel="适配方式"
              value={logoFit}
              onChange={(v) => {
                setLogoFit(v);
                if (saveError) setSaveError("");
              }}
              options={BRAND_LOGO_FITS.map((item) => ({ key: item.id, label: item.label }))}
            />
          </AdminSettingsRow>
        </>
      ) : (
        <AdminSettingsRow label="画幅与铺法">
          <p className="meta text-[12.5px]">纯文字页眉不显示 Logo。画幅和铺法只作用于图加文字和纯图。</p>
        </AdminSettingsRow>
      )}
      <AdminSettingsRow label="站点图标" hintBelow="设置不同主题的站点标识及浏览器图标" wide>
        <div className="admin-brand-slots">
          {SLOTS.map((s) =>
            renderSlot(
              s.id,
              s.label,
              s.hint,
              s.swatch,
              s.id === "logo_dark" ? dark : s.id === "favicon" ? favicon : light
            )
          )}
        </div>
      </AdminSettingsRow>
      <BrandMediaPicker
        open={picker != null}
        slot={picker || "logo_light"}
        onClose={() => setPicker(null)}
        onPick={(item) => {
          if (!picker) return;
          const [prev, set] = drafts[picker];
          if (prev.blob) URL.revokeObjectURL(prev.blob);
          set({ ...prev, file: null, blob: "", mediaId: item.id, mediaUrl: item.url });
        }}
      />
    </AdminSettingsGroup>
  );
}