"use client";

import { Check, ImagePlus, Images, Link2, X } from "lucide-react";
import { useEffect, useRef, useState, type Dispatch, type SetStateAction } from "react";
import {
  AdminSegmented,
  AdminSettingsActions,
  AdminSettingsGroup,
} 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,
  brandAliasPath,
  brandFileOk,
  type BrandLogoFit,
  type BrandLogoSize,
  type BrandMark,
  type BrandSlot,
} from "@/lib/brand";
import { toast } from "@/lib/toast";
import { densitySrcSet, isOwnImage, pickVariantWidth, variantURL } from "@/lib/responsiveImage";
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; swatch: "light" | "dark" | "neutral"; compact?: boolean }[] = [
  { id: "logo_light", label: "浅色 Logo", swatch: "light" },
  { id: "logo_dark", label: "深色 Logo", swatch: "dark" },
  { id: "favicon", label: "Favicon", swatch: "neutral", compact: true },
];

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 [copiedSlot, setCopiedSlot] = 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) return apiUploadBrand(slot, draft.file);
    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("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 slotDraft = (id: BrandSlot) =>
    id === "logo_dark" ? dark : id === "favicon" ? favicon : light;

  // 已保存的槽位 URL：存在才展示固定地址（未保存过无图可引用）
  const savedOf = (slot: BrandSlot) =>
    slot === "logo_dark" ? saved.dark : slot === "favicon" ? saved.favicon : saved.light;

  const copyAlias = async (slot: BrandSlot) => {
    try {
      await navigator.clipboard.writeText(`${window.location.origin}${brandAliasPath(slot)}`);
      setCopiedSlot(slot);
      toast("已复制固定地址", "ok");
      window.setTimeout(() => setCopiedSlot((cur) => (cur === slot ? null : cur)), 1500);
    } catch {
      toast("复制失败，请手动复制");
    }
  };

  const renderSlot = (slot: BrandSlot, label: string, swatch: "light" | "dark" | "neutral", compact?: boolean) => {
    const draft = slotDraft(slot);
    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-asset${compact ? " is-compact" : ""}`}>
        <div className={`admin-brand-swatch ${swatchClass}`}>
          {preview ? (
            // 预览槽（≤56px 高，宽标可能更宽）：本站图走 160/384 密度变体
            // eslint-disable-next-line @next/next/no-img-element
            <img
              src={isOwnImage(preview) ? variantURL(preview, pickVariantWidth(160)) : preview}
              srcSet={isOwnImage(preview) ? densitySrcSet(preview, 160) : undefined}
              alt=""
            />
          ) : (
            <span>未设置</span>
          )}
        </div>
        <div className="admin-brand-asset-meta">
          <span className="admin-brand-asset-label">{label}</span>
          {savedOf(slot) ? (
            <button
              type="button"
              className="admin-brand-alias"
              title="点击复制固定地址（换图不变链，友链引用请用此地址）"
              onClick={() => void copyAlias(slot)}
            >
              <Link2 size={12} aria-hidden />
              <span className="admin-brand-alias-url">{brandAliasPath(slot)}</span>
              {copiedSlot === slot ? <Check size={12} aria-hidden /> : null}
            </button>
          ) : null}
          <div className="admin-brand-asset-actions">
            <label className="btn btn-line btn-sm cursor-pointer">
              <ImagePlus size={14} /> 上传
              <input
                type="file"
                accept={brandAccept(slot)}
                className="hidden"
                aria-label={`上传${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} /> 库
            </button>
            <button
              type="button"
              className="admin-icon-btn"
              aria-label={`清除${label}`}
              disabled={saving || !preview}
              onClick={() => {
                if (draft.blob) URL.revokeObjectURL(draft.blob);
                drafts[slot][1](emptyDraft(""));
              }}
            >
              <X size={14} />
            </button>
          </div>
        </div>
      </div>
    );
  };

  return (
    <AdminSettingsGroup
      id="settings-brand"
      title="品牌"
      footer={
        <AdminSettingsActions
          dirty={dirty}
          saving={saving}
          saveLabel="保存"
          error={saveError}
          onSave={() => void save()}
          onDiscard={discard}
        />
      }
    >
      <div className="admin-brand-studio">
        <div className="admin-brand-studio-preview" aria-label="页眉预览">
          <div className="admin-brand-studio-chrome">
            <span aria-hidden />
            <span aria-hidden />
            <span aria-hidden />
          </div>
          <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>

        <div className="admin-brand-studio-toolbar">
          <div className="admin-brand-studio-field">
            <span className="admin-brand-studio-kicker">形式</span>
            <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" },
              ]}
            />
          </div>
          {mark !== "text" ? (
            <>
              <div className="admin-brand-studio-field">
                <span className="admin-brand-studio-kicker">比例</span>
                <div className="admin-brand-size-row" role="group" aria-label="Logo 比例">
                  {BRAND_LOGO_SIZES.map((item) => {
                    const on = logoSize === item.id;
                    return (
                      <button
                        key={item.id}
                        type="button"
                        className={`admin-brand-size-chip${on ? " is-on" : ""}`}
                        onClick={() => {
                          setLogoSize(item.id);
                          if (saveError) setSaveError("");
                        }}
                      >
                        <span className="admin-brand-size-chip-label">{item.label}</span>
                        <span className="admin-brand-size-chip-px">
                          {item.w}×{item.h}
                        </span>
                      </button>
                    );
                  })}
                </div>
              </div>
              <div className="admin-brand-studio-field">
                <span className="admin-brand-studio-kicker">铺法</span>
                <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 }))}
                />
              </div>
            </>
          ) : null}
        </div>

        <div className="admin-brand-studio-assets" aria-label="品牌素材">
          {SLOTS.map((s) => renderSlot(s.id, s.label, s.swatch, s.compact))}
        </div>
      </div>

      <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>
  );
}