"use client";

import { useCallback, useState } from "react";
import { useRouter } from "next/navigation";
import { Film, Loader2, Upload } from "lucide-react";
import { Button } from "@/components/ui/button";
import { cn, formatFileSize } from "@/lib/utils";

const MAX_SIZE = 500 * 1024 * 1024;
const ACCEPTED = ["video/mp4", "video/quicktime", "video/webm"];

export function VideoUpload() {
  const router = useRouter();
  const [dragging, setDragging] = useState(false);
  const [uploading, setUploading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const uploadFile = useCallback(async (file: File) => {
    setError(null);

    if (!ACCEPTED.includes(file.type) && !file.name.match(/\.(mp4|mov|webm)$/i)) {
      setError("Please upload MP4, MOV, or WebM.");
      return;
    }
    if (file.size > MAX_SIZE) {
      setError(`File too large (${formatFileSize(file.size)}). Max 500MB.`);
      return;
    }

    setUploading(true);
    try {
      const formData = new FormData();
      formData.append("video", file);

      const res = await fetch("/api/upload", { method: "POST", body: formData });
      const data = await res.json();
      if (!res.ok) throw new Error(data.error || "Upload failed");

      router.push(`/editor?id=${data.id}`);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Upload failed");
    } finally {
      setUploading(false);
    }
  }, [router]);

  const onDrop = (e: React.DragEvent) => {
    e.preventDefault();
    setDragging(false);
    const file = e.dataTransfer.files?.[0];
    if (file) void uploadFile(file);
  };

  return (
    <div className="mx-auto w-full max-w-xl space-y-4">
      <div
        onDragOver={(e) => { e.preventDefault(); setDragging(true); }}
        onDragLeave={() => setDragging(false)}
        onDrop={onDrop}
        className={cn(
          "flex min-h-[320px] cursor-pointer flex-col items-center justify-center rounded-2xl border-2 border-dashed p-10 transition-colors",
          dragging ? "border-zinc-900 bg-zinc-50" : "border-zinc-300 bg-white hover:border-zinc-400",
        )}
        onClick={() => document.getElementById("video-input")?.click()}
      >
        <input
          id="video-input"
          type="file"
          accept="video/mp4,video/quicktime,video/webm,.mp4,.mov,.webm"
          className="hidden"
          onChange={(e) => {
            const file = e.target.files?.[0];
            if (file) void uploadFile(file);
          }}
        />
        {uploading ? (
          <Loader2 className="h-12 w-12 animate-spin text-zinc-500" />
        ) : (
          <Upload className="h-12 w-12 text-zinc-400" />
        )}
        <h2 className="mt-4 text-xl font-semibold">Drop video here</h2>
        <p className="mt-2 text-sm text-zinc-500">or click to browse</p>
        <p className="mt-4 text-xs text-zinc-400">MP4, MOV, WebM • Max 500MB • 5 min</p>
      </div>

      {error && (
        <div className="rounded-lg border border-red-200 bg-red-50 px-4 py-3 text-sm text-red-700">
          {error}
        </div>
      )}

      <div className="flex items-center gap-2 rounded-lg bg-zinc-100 px-4 py-3 text-sm text-zinc-600">
        <Film className="h-4 w-4" />
        Upload a short vertical video to add viral-style captions
      </div>
    </div>
  );
}