"use client";

import { useRef, useState } from "react";
import { useTranslations } from "next-intl";
import { useRouter } from "next/navigation";
import { Camera, Loader2 } from "lucide-react";
import { toast } from "sonner";
import { Button } from "@/components/ui/button";
import { FakeProgressBar } from "@/components/ui/fake-progress-bar";

export function PhotoImportButton() {
  const t = useTranslations("recipe");
  const router = useRouter();
  const fileRef = useRef<HTMLInputElement>(null);
  const [loading, setLoading] = useState(false);
  const [stage, setStage] = useState<"recognizing" | "generating">("recognizing");
  const stageTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  function handleClick() {
    fileRef.current?.click();
  }

  async function handleFile(e: React.ChangeEvent<HTMLInputElement>) {
    const file = e.target.files?.[0];
    if (!file) return;

    setLoading(true);
    setStage("recognizing");
    // The photo-import flow is two sequential AI calls (vision recognition,
    // then text generation) behind a single request/response — there's no
    // real progress signal to react to, so this just approximates the
    // handoff point for the loading copy.
    stageTimerRef.current = setTimeout(() => setStage("generating"), 5000);

    try {
      const base64 = await new Promise<string>((resolve, reject) => {
        const reader = new FileReader();
        reader.onload = () => {
          const result = reader.result as string;
          // Strip the data:mime/type;base64, prefix
          const comma = result.indexOf(",");
          resolve(comma !== -1 ? result.slice(comma + 1) : result);
        };
        reader.onerror = () => reject(reader.error);
        reader.readAsDataURL(file);
      });

      const res = await fetch("/api/v1/ai/import-photo", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          imageBase64: base64,
          mimeType: file.type,
        }),
      });

      if (!res.ok) {
        if (res.status === 422) throw new Error(t("photoNoRecipeFound"));
        const data = await res.json().catch(() => ({})) as { error?: string };
        throw new Error(data.error ?? `Request failed: ${res.status}`);
      }

      const { id } = await res.json() as { id: string };
      router.push(`/recipes/${id}/edit`);
    } catch (err) {
      toast.error(err instanceof Error ? err.message : t("photoImportFailed"));
    } finally {
      if (stageTimerRef.current) clearTimeout(stageTimerRef.current);
      setLoading(false);
      // Reset input so the same file can be re-selected
      if (fileRef.current) fileRef.current.value = "";
    }
  }

  return (
    <div className="space-y-2">
      <input
        ref={fileRef}
        type="file"
        accept="image/jpeg,image/png,image/webp"
        className="hidden"
        onChange={handleFile}
      />
      <Button onClick={handleClick} disabled={loading} variant="outline">
        {loading ? (
          <Loader2 className="mr-2 h-4 w-4 animate-spin" />
        ) : (
          <Camera className="mr-2 h-4 w-4" />
        )}
        {t("importFromPhoto")}
      </Button>
      <FakeProgressBar
        active={loading}
        durationMs={12000}
        label={loading ? (stage === "recognizing" ? t("recognizingPhoto") : t("writingRecipe")) : undefined}
      />
    </div>
  );
}