package io.gitlab.jfronny.libjf;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Type;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class HttpUtils {
    private static final HttpClient CLIENT = HttpClient.newBuilder().followRedirects(HttpClient.Redirect.ALWAYS).build();

    private enum Method {
        GET, POST
    }

    public static class Request {
        private static final Pattern CURSEFORGE_API = Pattern.compile("(?:http(s)?://)?addons-ecs\\.forgesvc\\.net/api/+");
        private final String url;
        private final HttpRequest.Builder builder;
        private Method method;
        private int sent = 0;

        public Request(Method method, String url) throws URISyntaxException {
            this.url = url.replace(" ", "%20");
            this.builder = HttpRequest.newBuilder()
                    .uri(new URI(this.url))
                    .header("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36");
            this.method = method;
        }

        public Request bearer(String token) {
            builder.header("Authorization", "Bearer " + token);

            return this;
        }

        public Request header(String name, String value) {
            builder.header(name, value);
            return this;
        }

        public Request bodyString(String string) {
            builder.header("Content-Type", "text/plain");
            builder.method(method.name(), HttpRequest.BodyPublishers.ofString(string));
            method = null;

            return this;
        }

        public Request bodyForm(String string) {
            builder.header("Content-Type", "application/x-www-form-urlencoded");
            builder.method(method.name(), HttpRequest.BodyPublishers.ofString(string));
            method = null;

            return this;
        }

        public Request bodyForm(Map<String, String> entries) {
            return bodyForm(entries.entrySet()
                    .stream()
                    .map(entry -> URLEncoder.encode(entry.getKey(), StandardCharsets.UTF_8) + '=' + URLEncoder.encode(entry.getValue(), StandardCharsets.UTF_8))
                    .collect(Collectors.joining("&")));
        }

        public Request bodyJson(String string) {
            builder.header("Content-Type", "application/json");
            builder.method(method.name(), HttpRequest.BodyPublishers.ofString(string));
            method = null;

            return this;
        }

        public Request bodyJson(Object object) {
            builder.header("Content-Type", "application/json");
            builder.method(method.name(), HttpRequest.BodyPublishers.ofString(LibJf.GSON.toJson(object)));
            method = null;

            return this;
        }

        private <T> T _send(String accept, HttpResponse.BodyHandler<T> responseBodyHandler) throws IOException {
            sent++;
            if (sent > 3) throw new IOException("Attempted third redirect, stopping");
            builder.header("Accept", accept);
            if (method != null) builder.method(method.name(), HttpRequest.BodyPublishers.noBody());

            HttpResponse<T> res;
            try {
                res = CLIENT.send(builder.build(), responseBodyHandler);
            } catch (InterruptedException e) {
                throw new IOException("Could not send request", e);
            }
            if (res.statusCode() == 200) return res.body();
            Optional<String> location = res.headers().firstValue("location");
            // Redirect
            if (location.isPresent() && (res.statusCode() == 302 || res.statusCode() == 307) && method == Method.GET) {
                try {
                    return HttpUtils.get(location.get())._send(accept, responseBodyHandler);
                } catch (URISyntaxException e) {
                    throw new IOException("Could not follow redirect", e);
                }
            }
            // CurseForge serverside error
            if (CURSEFORGE_API.matcher(url).matches() && res.statusCode() >= 500 && res.statusCode() < 600) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new IOException("Could not sleep before resending request" + e);
                }
                return _send(accept, responseBodyHandler);
            }
            throw new IOException("Unexpected return method: " + res.statusCode() + " (URL=" + url + ")");
        }

        public void send() throws IOException {
            _send("*/*", HttpResponse.BodyHandlers.discarding());
        }

        public InputStream sendInputStream() throws IOException {
            return _send("*/*", HttpResponse.BodyHandlers.ofInputStream());
        }

        public String sendString() throws IOException {
            return _send("*/*", HttpResponse.BodyHandlers.ofString());
        }

        public Stream<String> sendLines() throws IOException {
            return _send("*/*", HttpResponse.BodyHandlers.ofLines());
        }

        public <T> T sendJson(Type type) throws IOException {
            InputStream in = _send("application/json", HttpResponse.BodyHandlers.ofInputStream());
            return in == null ? null : LibJf.GSON.fromJson(new InputStreamReader(in), type);
        }

        private String getString(Object a) throws IOException {
            if (a instanceof InputStream s) return new String(s.readAllBytes());
            if (a instanceof String s) return s;
            if (a instanceof Stream s) return ((Stream<String>)s).collect(Collectors.joining());
            return "";
        }
    }

    public static Request get(String url) throws URISyntaxException {
        return new Request(Method.GET, url);
    }

    public static Request post(String url) throws URISyntaxException {
        return new Request(Method.POST, url);
    }
}