using System.Threading.Tasks;
using Elwig.Windows;
using System.Diagnostics;
using System;
using System.IO;
using System.Collections.Generic;
using System.Windows;
using System.Text.RegularExpressions;
using System.Linq;
using System.Net.Sockets;
using System.Text;

namespace Elwig.Helpers.Printing {
    public static class Pdf {

        private static readonly string PdfToPrinter = new string[] { App.ExePath }
            .Union(Environment.GetEnvironmentVariable("PATH")?.Split(';') ?? [])
            .Select(x => Path.Combine(x, "PDFtoPrinter.exe"))
            .Where(File.Exists)
            .FirstOrDefault() ?? throw new FileNotFoundException("PDFtoPrinter executable not found");
        private static readonly string WinziPrint = new string[] { App.ExePath }
            .Union(Environment.GetEnvironmentVariable("PATH")?.Split(';') ?? [])
            .Select(x => Path.Combine(x, "WinziPrint.exe"))
            .Where(File.Exists)
            .FirstOrDefault() ?? throw new FileNotFoundException("WiniPrint executable not found");
        private static Process? WinziPrintProc;
        public static bool IsReady => WinziPrintProc != null;

        public static async Task Init(Action? evtHandler = null) {
            // NOTE: If the WinziPrint daemon is already running this will succeed, but the process will fail.
            //       Should be no problem, as long as the daemon is not closed
            var p = new Process() { StartInfo = new() {
                FileName = WinziPrint,
                CreateNoWindow = true,
                UseShellExecute = false,
                RedirectStandardOutput = true,
            } };
            p.StartInfo.ArgumentList.Add("-D");
            p.StartInfo.ArgumentList.Add("-d");
            p.StartInfo.ArgumentList.Add(App.TempPath);
            p.Start();
            await p.StandardOutput.ReadLineAsync();
            WinziPrintProc = p;
            evtHandler?.Invoke();
        }

        public static Task Cleanup() {
            WinziPrintProc?.Kill(true);
            WinziPrintProc?.Close();
            return Task.CompletedTask;
        }

        public static async Task<(int Pages, IEnumerable<int> PerDoc)> Convert(string htmlPath, string pdfPath, bool doublePaged = false, IProgress<double>? progress = null) {
            return await Convert([htmlPath], pdfPath, doublePaged, progress);
        }

        public static async Task<(int Pages, IEnumerable<int> PerDoc)> Convert(IEnumerable<string> htmlPath, string pdfPath, bool doublePaged = false, IProgress<double>? progress = null) {
            if (WinziPrintProc == null) throw new InvalidOperationException("The WinziPrint process has not been initialized yet");
            progress?.Report(0.0);
            using var client = new TcpClient("127.0.0.1", 30983);
            using var stream = client.GetStream();
            await stream.WriteAsync(Encoding.UTF8.GetBytes(
                "-e utf-8;-p;" + (doublePaged ? "-2;" : "") +
                $"{string.Join(';', htmlPath)};{pdfPath}" +
                "\r\n"));
            using var reader = new StreamReader(stream);
            while (true) {
                var line = await reader.ReadLineAsync() ?? throw new IOException("Invalid response from WinziPrint");
                if (line.StartsWith("error:")) {
                    throw new IOException($"WinziPrint: {line[6..].Trim()}");
                } else if (line.StartsWith("progress:")) {
                    var parts = line[9..].Trim().Split('/').Select(int.Parse).ToArray();
                    progress?.Report(100.0 * parts[0] / parts[1]);
                } else if (line.StartsWith("success:")) {
                    var m = Regex.Match(line, @"([0-9]+) pages \(([0-9, ]+)\)");
                    return (int.Parse(m.Groups[1].Value), m.Groups[2].Value.Split(", ").Select(int.Parse).ToList());
                }
            }
        }

        public static void Show(TempFile file, string title) {
            App.MainDispatcher.BeginInvoke(() => {
                var w = new DocumentViewerWindow(title, file);
                w.Show();
            });
        }

        public static void Show(string path, string title) {
            App.MainDispatcher.BeginInvoke(() => {
                var w = new DocumentViewerWindow(title, path);
                w.Show();
            });
        }

        public static async Task Print(string path, int copies = 1) {
            try {
                var p = new Process() { StartInfo = new() { FileName = PdfToPrinter } };
                p.StartInfo.ArgumentList.Add(path);
                p.StartInfo.ArgumentList.Add("/s");
                p.StartInfo.ArgumentList.Add($"copies={copies}");
                p.Start();
                await p.WaitForExitAsync();
            } catch (Exception e) {
                MessageBox.Show("Beim Drucken ist ein Fehler aufgetreten:\n\n" + e.Message, "Fehler beim Drucken");
            }
        }
    }
}
