"use client";

import { Loader2, Paperclip, X } from "lucide-react";
import { useRef, useState } from "react";
import { Button } from "@/components/ui/button";
import { tr } from "@/i18n/tr";
import type { ActionResult } from "@/lib/action-result";
import { cn } from "@/lib/utils";
import {
  acceptAttribute,
  MAX_ATTACHMENTS_PER_RECORD,
  type AttachmentKind,
} from "@/shared/attachments";
import type { AttachmentInfo } from "../service";
import { AttachmentThumb } from "./attachment-strip";
import { AttachmentViewer } from "./attachment-viewer";

const t = tr.attachments;

/** Tek dosyayı /api/files'a yükler. */
async function uploadFile(file: File): Promise<ActionResult<AttachmentInfo>> {
  const body = new FormData();
  body.append("file", file);
  try {
    const res = await fetch("/api/files", { method: "POST", body });
    return (await res.json()) as ActionResult<AttachmentInfo>;
  } catch {
    return { ok: false, error: t.errors.upload };
  }
}

/**
 * Formdaki küçük "Ek ekle" alanı (Bölüm 6.3): seçilen dosyalar hemen yüklenir (bekleyen ek),
 * küçük önizleme ve sayaç gösterilir; kayıt kaydedilince ekler kayda bağlanır.
 */
export function AttachmentPicker({
  value,
  onChange,
  allowedKinds,
  onBusyChange,
}: {
  value: AttachmentInfo[];
  onChange: (items: AttachmentInfo[]) => void;
  allowedKinds: readonly AttachmentKind[];
  onBusyChange?: (busy: boolean) => void;
}) {
  const inputRef = useRef<HTMLInputElement>(null);
  const [uploading, setUploading] = useState(0);
  const [errors, setErrors] = useState<string[]>([]);
  const [viewer, setViewer] = useState<number | null>(null);
  const invalid = value.filter((a) => !allowedKinds.includes(a.kind));
  const room = MAX_ATTACHMENTS_PER_RECORD - value.length;

  async function onFiles(files: FileList | null) {
    if (!files?.length) return;
    const list = [...files];
    const accepted = list.slice(0, Math.max(0, room));
    const nextErrors: string[] = [];
    if (list.length > accepted.length)
      nextErrors.push(t.errors.tooMany(MAX_ATTACHMENTS_PER_RECORD));
    setUploading(accepted.length);
    onBusyChange?.(true);
    let items = value;
    for (const file of accepted) {
      const result = await uploadFile(file);
      if (result.ok) {
        items = [...items, result.data];
        onChange(items);
      } else {
        nextErrors.push(`${file.name}: ${result.error}`);
      }
      setUploading((n) => n - 1);
    }
    setErrors(nextErrors);
    onBusyChange?.(false);
    if (inputRef.current) inputRef.current.value = "";
  }

  function remove(id: string) {
    onChange(value.filter((a) => a.id !== id));
  }

  return (
    <div className="flex flex-col gap-2">
      <div className="flex flex-wrap items-center gap-2">
        <Button
          type="button"
          variant="outline"
          size="sm"
          onClick={() => inputRef.current?.click()}
          disabled={room <= 0 || uploading > 0}
        >
          {uploading > 0 ? <Loader2 className="animate-spin" /> : <Paperclip />}
          {uploading > 0 ? t.uploading : t.add}
        </Button>
        <span className="text-xs text-muted-foreground">
          {value.length
            ? t.count(value.length)
            : allowedKinds.includes("pdf")
              ? t.addHint.imagePdf
              : t.addHint.image}
        </span>
        <input
          ref={inputRef}
          type="file"
          multiple
          accept={acceptAttribute(allowedKinds)}
          className="sr-only"
          tabIndex={-1}
          aria-label={t.add}
          onChange={(e) => onFiles(e.target.files)}
        />
      </div>

      {value.length || uploading ? (
        <ul className="flex flex-wrap gap-1.5">
          {value.map((item, i) => (
            <li key={item.id} className="relative">
              <AttachmentThumb
                item={item}
                className={cn(
                  "size-10",
                  !allowedKinds.includes(item.kind) && "border-destructive ring-1 ring-destructive",
                )}
                onClick={() => setViewer(i)}
              />
              <button
                type="button"
                onClick={() => remove(item.id)}
                className="absolute -top-1.5 -right-1.5 flex size-5 items-center justify-center rounded-full border bg-background text-muted-foreground shadow-sm hover:text-foreground"
                aria-label={`${t.remove}: ${item.name}`}
              >
                <X className="size-3" />
              </button>
            </li>
          ))}
          {Array.from({ length: uploading }, (_, i) => (
            <li
              key={`up-${i}`}
              className="flex size-10 items-center justify-center rounded-md border border-dashed"
              aria-label={t.uploading}
            >
              <Loader2 className="size-4 animate-spin text-muted-foreground" />
            </li>
          ))}
        </ul>
      ) : null}

      {invalid.length ? (
        <p className="text-xs text-destructive" role="alert">
          {t.errors.kindNotAllowed}
        </p>
      ) : null}
      {errors.map((e) => (
        <p key={e} className="text-xs text-destructive" role="alert">
          {e}
        </p>
      ))}

      <AttachmentViewer
        items={value}
        startIndex={viewer ?? 0}
        open={viewer !== null}
        onOpenChange={(open) => !open && setViewer(null)}
      />
    </div>
  );
}