import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';

import 'package:http_parser/http_parser.dart';
import 'package:belatuk_http_server/belatuk_http_server.dart';
import 'package:mime/mime.dart';

import 'body_parse_result.dart';
import 'file_upload_info.dart';
import 'map_from_uri.dart';

/// Forwards to [parseBodyFromStream].
@Deprecated("parseBodyFromStream")
Future<BodyParseResult> parseBody(HttpRequest request,
    {bool storeOriginalBuffer = false}) {
  return parseBodyFromStream(
      request,
      request.headers.contentType != null
          ? MediaType.parse(request.headers.contentType.toString())
          : null,
      request.uri,
      storeOriginalBuffer: storeOriginalBuffer);
}

/// Grabs data from an incoming request.
///
/// Supports URL-encoded and JSON, as well as multipart/* forms.
/// On a file upload request, only fields with the name **'file'** are processed
/// as files. Anything else is put in the body. You can change the upload file name
/// via the *fileUploadName* parameter. :)
///
/// Use [storeOriginalBuffer] to add  the original request bytes to the result.
Future<BodyParseResult> parseBodyFromStream(
    Stream<Uint8List> data, MediaType? contentType, Uri requestUri,
    {bool storeOriginalBuffer = false}) async {
  var result = _BodyParseResultImpl();

  Future<Uint8List> getBytes() {
    return data
        .fold<BytesBuilder>(BytesBuilder(copy: false), (a, b) => a..add(b))
        .then((b) => b.takeBytes());
  }

  Future<String> getBody() {
    if (storeOriginalBuffer) {
      return getBytes().then((bytes) {
        result.originalBuffer = bytes;
        return utf8.decode(bytes);
      });
    } else {
      return utf8.decoder.bind(data).join();
    }
  }

  try {
    if (contentType != null) {
      if (contentType.type == 'multipart' &&
          contentType.parameters.containsKey('boundary')) {
        Stream<Uint8List> stream;

        if (storeOriginalBuffer) {
          var bytes = result.originalBuffer = await getBytes();
          var ctrl = StreamController<Uint8List>()..add(bytes);
          await ctrl.close();
          stream = ctrl.stream;
        } else {
          stream = data;
        }

        var parts =
            MimeMultipartTransformer(contentType.parameters['boundary']!)
                .bind(stream)
                .map((part) =>
                    HttpMultipartFormData.parse(part, defaultEncoding: utf8));

        await for (HttpMultipartFormData part in parts) {
          if (part.isBinary ||
              part.contentDisposition.parameters.containsKey('filename')) {
            var builder = await part.fold(
                BytesBuilder(copy: false),
                (BytesBuilder b, d) =>
                    b..add(d is! String ? (d as List<int>?)! : d.codeUnits));
            var upload = FileUploadInfo(
                mimeType: part.contentType!.mimeType,
                name: part.contentDisposition.parameters['name'],
                filename:
                    part.contentDisposition.parameters['filename'] ?? 'file',
                data: builder.takeBytes());
            result.files.add(upload);
          } else if (part.isText) {
            var text = await part.join();
            buildMapFromUri(result.body,
                '${part.contentDisposition.parameters["name"]}=$text');
          }
        }
      } else if (contentType.mimeType == 'application/json') {
        result.body.addAll(
            _foldToStringDynamic(json.decode(await getBody()) as Map?)!);
      } else if (contentType.mimeType == 'application/x-www-form-urlencoded') {
        var body = await getBody();
        buildMapFromUri(result.body, body);
      } else if (storeOriginalBuffer == true) {
        result.originalBuffer = await getBytes();
      }
    } else {
      if (requestUri.hasQuery) {
        buildMapFromUri(result.query, requestUri.query);
      }

      if (storeOriginalBuffer == true) {
        result.originalBuffer = await getBytes();
      }
    }
  } catch (e, st) {
    result.error = e;
    result.stack = st;
  }

  return result;
}

class _BodyParseResultImpl implements BodyParseResult {
  @override
  Map<String?, dynamic> body = {};

  @override
  List<FileUploadInfo> files = [];

  @override
  List<int>? originalBuffer;

  @override
  Map<String?, dynamic> query = {};

  @override
  dynamic error;

  @override
  StackTrace? stack;
}

Map<String, dynamic>? _foldToStringDynamic(Map? map) {
  return map?.keys.fold<Map<String, dynamic>>(
      <String, dynamic>{}, (out, k) => out..[k.toString()] = map[k]);
}