import 'dart:io';
import 'dart:math';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'package:pdf_image_renderer/pdf_image_renderer.dart';
import 'package:riverpod_annotation/riverpod_annotation.dart';

part 'pdf_viewer.g.dart';

@riverpod
Future<Uint8List> _renderPdf(
  Ref ref, {
  String? path,
  Uint8List? pdfBytes,
}) async {
  assert(path != null || pdfBytes != null);

  // Create temporary file if required
  var isTemp = false;
  if (path == null) {
    path = p.join(
      (await getTemporaryDirectory()).absolute.path,
      "render-${Random().nextInt(10000).toString()}+.pdf",
    );

    await File(path).writeAsBytes(pdfBytes!);
    isTemp = true;
  }

  try {
    final pdf = PdfImageRenderer(path: path);
    await pdf.open();
    await pdf.openPage(pageIndex: 0);

    // get the render size after the page is loaded
    final size = await pdf.getPageSize(pageIndex: 0);

    // get the actual image of the page
    final img = await pdf.renderPage(
      pageIndex: 0,
      x: 0,
      y: 0,
      width: size.width,
      // you can pass a custom size here to crop the image
      height: size.height,
      // you can pass a custom size here to crop the image
      scale: 1,
      // increase the scale for better quality (e.g. for zooming)
      background: Colors.white,
    );

    // close the page again
    await pdf.closePage(pageIndex: 0);

    // close the PDF after rendering the page
    pdf.close();

    return img!;
  } finally {
    if (isTemp) {
      await File(path).delete();
    }
  }
}

class PDFViewer extends ConsumerWidget {
  final String? pdfPath;
  final Uint8List? pdfBytes;
  final double? width;
  final double? height;
  final BoxFit? fit;

  const PDFViewer({
    super.key,
    this.pdfPath,
    this.pdfBytes,
    this.width,
    this.height,
    this.fit,
  }) : assert(pdfPath != null || pdfBytes != null);

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final provider = ref.watch(
      _renderPdfProvider(path: pdfPath, pdfBytes: pdfBytes),
    );

    // Perform a switch-case on the result to handle loading/error states
    return switch (provider) {
      AsyncData(:final value) => Image(
        image: MemoryImage(value),
        width: width,
        height: height,
        fit: fit,
      ),
      AsyncError(:final error) => Text('PDF error: $error'),
      _ => const CircularProgressIndicator(),
    };
  }
}