import { useCallback, useEffect, useRef, useState } from "react";
import { Copy, ImageUp, Star, Trash2 } from "lucide-react";
import { api } from "../api.js";
import { useAuth } from "../App.jsx";
import { Badge, Button, Dialog, ErrorNote, Panel, Spinner, timeAgo } from "../ui.jsx";

const monthLabel = (m) => new Date(`${m}-15`).toLocaleDateString("en-CA", { month: "long", year: "numeric" });

/** Client page tab: the monthly screenshot checklist the team fills and the audit reads. */
export default function Screenshots({ slug, clientName }) {
  const { isAdmin } = useAuth();
  const [month, setMonth] = useState(null);
  const [data, setData] = useState(null);
  const [error, setError] = useState(null);
  const [busy, setBusy] = useState(null);
  const [view, setView] = useState(null); // { title, src }
  const [copied, setCopied] = useState(false);

  const load = useCallback(() => api(`/api/clients/${slug}/screenshots${month ? `?month=${month}` : ""}`).then((d) => { setData(d); setError(null); }).catch(setError), [slug, month]);
  useEffect(() => { load(); }, [load]);

  const act = async (id, fn) => {
    setBusy(id); setError(null);
    try { setData(await fn()); } catch (e) { setError(e); }
    setBusy(null);
  };
  const q = `?month=${data?.month}`;
  const upload = (shot, file) => act(shot.id, async () => {
    const res = await fetch(`/api/clients/${slug}/screenshots/${shot.id}${q}`, { method: "POST", credentials: "same-origin", headers: { "X-Filename": encodeURIComponent(file.name), "Content-Type": "application/octet-stream" }, body: file });
    const out = await res.json().catch(() => ({}));
    if (!res.ok) throw new Error(out.error || `Upload failed (${res.status})`);
    return out;
  });

  const copyChecklist = async () => {
    const lines = data.shots.map((s, i) => `${i + 1}. ${s.platform}, ${s.label}${s.required ? "" : " (if it exists)"}: ${s.how}`);
    await navigator.clipboard.writeText(`Screenshots for ${clientName}, ${monthLabel(data.month)}\nUpload them in Quorla → ${clientName} → Screenshots.\n\n${lines.join("\n")}`);
    setCopied(true); setTimeout(() => setCopied(false), 2000);
  };

  if (!data) return error ? <ErrorNote error={error} /> : <Spinner />;
  const required = data.shots.filter((s) => s.required);
  const done = required.filter((s) => s.file).length;

  return (
    <div className="space-y-4">
      <Panel
        title="Monthly screenshots"
        subtitle="Take these in a computer browser before the monthly audit (Windows: Win+Shift+S). The audit reads them for what the numbers can't show: bio, highlights, how the feed looks, buttons and reviews."
        action={
          <div className="flex items-center gap-2">
            <label htmlFor="ss-month" className="sr-only">Month</label>
            <select id="ss-month" className="input h-8 w-auto" value={data.month} onChange={(e) => setMonth(e.target.value)}>
              {data.months.map((m) => <option key={m} value={m}>{monthLabel(m)}</option>)}
            </select>
            <Button size="sm" icon={Copy} onClick={copyChecklist}>{copied ? "Copied" : "Copy checklist"}</Button>
          </div>
        }
      >
        <p className="text-[13px] text-ink-2">
          <span className="num font-semibold text-ink">{done} of {required.length}</span> required screenshots uploaded for {monthLabel(data.month)}.
          {done === required.length && " Ready for the audit."}
        </p>
      </Panel>

      <ErrorNote error={error} />

      <div className="grid gap-4 sm:grid-cols-2 xl:grid-cols-3">
        {data.shots.map((s) => (
          <ShotCard key={s.id} shot={s} slug={slug} q={q} busy={busy === s.id} isAdmin={isAdmin}
            onUpload={(f) => upload(s, f)}
            onRemove={() => act(s.id, () => api(`/api/clients/${slug}/screenshots/${s.id}${q}`, { method: "DELETE" }))}
            onExample={() => act(s.id, () => api(`/api/clients/${slug}/screenshots/${s.id}/example${q}`, { method: "POST" }))}
            onView={setView} />
        ))}
      </div>

      <Dialog open={!!view} onClose={() => setView(null)} title={view?.title} wide>
        {view && <img src={view.src} alt={view.title} className="mx-auto max-h-[70vh] w-auto rounded-lg border border-line" />}
      </Dialog>
    </div>
  );
}

function ShotCard({ shot, slug, q, busy, isAdmin, onUpload, onRemove, onExample, onView }) {
  const input = useRef(null);
  const [drag, setDrag] = useState(false);
  const title = `${shot.platform} · ${shot.label}`;
  const stamp = shot.file?.at ? `&v=${encodeURIComponent(shot.file.at)}` : "";
  const src = `/api/clients/${slug}/screenshots/${shot.id}/image${q}${stamp}`;
  const exampleSrc = `/api/screenshot-examples/${shot.id}`;
  const pick = (files) => files?.[0] && onUpload(files[0]);

  return (
    <section className="rounded-xl border border-line bg-white flex flex-col">
      <header className="px-4 pt-3.5 pb-2 flex items-start justify-between gap-2">
        <div className="min-w-0">
          <p className="text-[11.5px] font-medium text-muted uppercase tracking-wide">{shot.platform}</p>
          <h3 className="text-[14px] font-semibold text-ink">{shot.label}</h3>
        </div>
        {shot.file ? <Badge tone="ok" dot>Uploaded</Badge> : shot.required ? <Badge tone="warn">Required</Badge> : <Badge>Optional</Badge>}
      </header>
      <p className="px-4 text-[12.5px] text-ink-2 leading-relaxed">{shot.how}</p>

      <div className="p-4 mt-auto">
        {shot.file ? (
          <button type="button" onClick={() => onView({ title, src })} className="block w-full h-56 rounded-lg border border-line bg-canvas overflow-hidden">
            <img src={src} alt={`${title} screenshot`} className="h-full w-full object-contain" loading="lazy" />
          </button>
        ) : (
          <div
            onDragOver={(e) => { e.preventDefault(); setDrag(true); }}
            onDragLeave={() => setDrag(false)}
            onDrop={(e) => { e.preventDefault(); setDrag(false); pick(e.dataTransfer.files); }}
            className={`h-56 rounded-lg border border-dashed flex flex-col items-center justify-center gap-2 text-center px-3 ${drag ? "border-brand bg-brand/5" : "border-line bg-canvas"}`}
          >
            {busy ? <Spinner label="Uploading" /> : (
              <>
                <ImageUp className="size-6 text-faint" aria-hidden="true" />
                <p className="text-[12.5px] text-muted">Drop the screenshot here</p>
                <Button size="sm" onClick={() => input.current?.click()}>Choose file</Button>
              </>
            )}
          </div>
        )}
        <input ref={input} type="file" accept="image/png,image/jpeg,image/webp" className="sr-only" aria-label={`Upload ${title}`} onChange={(e) => { pick(e.target.files); e.target.value = ""; }} />

        <div className="mt-2.5 flex flex-wrap items-center gap-x-3 gap-y-1 text-[12px] text-muted">
          {shot.file && <span>{shot.file.by ? `${shot.file.by}, ` : ""}{timeAgo(shot.file.at)}</span>}
          {shot.example && <button type="button" className="underline hover:text-ink" onClick={() => onView({ title: `Example: ${title}`, src: exampleSrc })}>See example</button>}
          {shot.file && (
            <span className="ml-auto flex items-center gap-1">
              <Button size="sm" loading={busy} onClick={() => input.current?.click()}>Replace</Button>
              {isAdmin && <Button size="sm" icon={Star} title="Show this shot as the example for every client" onClick={onExample}>Use as example</Button>}
              <button type="button" onClick={onRemove} className="p-1.5 rounded hover:bg-bad-soft text-muted hover:text-bad" aria-label={`Remove ${title}`}><Trash2 className="size-4" /></button>
            </span>
          )}
        </div>
      </div>
    </section>
  );
}