using System;
using System.IO;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace bytex64.WebThing {
    public class Config {
        public static string ConfigurationPrefix = "/etc";

        public static Dictionary<string,string> Options;
        public static Dictionary<string,Dictionary<string,string>> PluginOptions;
        public static string[] Arguments;
        private static HashSet<string> CommandLineOptions;

        public static Regex item_re = new Regex(@"^(?:([\w.]+)\.)?(\w+)$");
        public static Regex file_var_re = new Regex(@"^([\w.]+)\s*=\s*(.*)$");

        static Config() {
            Options = new Dictionary<string,string>();
            PluginOptions = new Dictionary<string,Dictionary<string,string>>();
            CommandLineOptions = new HashSet<string>();
        }

        private static void ParseOption(string key, string val) {
            Match m = item_re.Match(key);
            string plugin = m.Groups[1].Value;
            string name = m.Groups[2].Value;
            if (plugin.Length > 0) {   // Plugin Option
                if (!PluginOptions.ContainsKey(plugin))
                    PluginOptions[plugin] = new Dictionary<string,string>();
                PluginOptions[plugin][name] = val;
            } else {                   // Global Option
                Options[name] = val;
            }
        }

        public static void DumpOptions() {
            Console.WriteLine("Options:");
            foreach (string key in Options.Keys)
                Console.WriteLine("   {0}\t{1}", key, Options[key]);

            Console.WriteLine("Plugin Options:");
            foreach (string plugin in PluginOptions.Keys) {
                Console.WriteLine("    {0}", plugin);
                foreach (string key in PluginOptions[plugin].Keys)
                    Console.WriteLine("        {0}\t{1}", key, PluginOptions[plugin][key]);
            }

            Console.WriteLine("Arguments: {0}", String.Join(" ", Arguments));
        }

        public static void ParseCommandLine() {
            Queue<string> q = new Queue<string>();
            foreach (string s in System.Environment.GetCommandLineArgs()) {
                q.Enqueue(s);
            }
            q.Dequeue();   // Remove self argument

            Regex SimpleOpt = new Regex(@"^-([\w.]+)(?:[:=](.*))?$");
            Regex LongOpt   = new Regex(@"^--([\w.]+)$");
            List<string> args = new List<string>();

            while (q.Count > 0) {
                string opt = q.Dequeue();
                Match m;
                   
                m = SimpleOpt.Match(opt);
                if (m.Success) {
                    string key = m.Groups[1].Value;
                    string val = m.Groups[2].Value;
                    if (val.Length > 0) {
                        ParseOption(key, val);
                    } else {
                        ParseOption(key, null);
                    }
                    CommandLineOptions.Add(key);
                    continue;
                }

                m = LongOpt.Match(opt);
                if (m.Success) {
                    string key = m.Groups[1].Value;
                    if (q.Count > 0) {
                        string val = q.Peek();
                        if (!(SimpleOpt.IsMatch(val) || LongOpt.IsMatch(val))) {
                            q.Dequeue();
                            ParseOption(key, val);
                        } else {
                            ParseOption(key, null);
                        }
                    } else {
                        ParseOption(key, null);
                    }
                    CommandLineOptions.Add(key);
                    continue;
                }

                // else

                args.Add(opt);
            }
            Arguments = args.ToArray();
        }

        public static void Load() {
            LoadFile(ConfigurationPrefix + "/WebThing.conf");
            LoadFile(Environment.GetEnvironmentVariable("HOME") + "/.config/WebThing/WebThing.conf");
            if (Options.ContainsKey("config"))
                LoadFile(Options["config"]);
        }

        public static void LoadFile(string filename) {
            TextReader f;
            try {
                f = new StreamReader(File.OpenRead(filename));
            } catch (FileNotFoundException) {
                Console.WriteLine("Could not open configuration file {0}", filename);
                return;
            }

            string line;
            while ((line = f.ReadLine()) != null) {
                Match m = file_var_re.Match(line.Trim());
                if (m.Success) {
                    string key = m.Groups[1].Value;
                    if (!CommandLineOptions.Contains(key))
                        ParseOption(key, m.Groups[2].Value);
                }
            }

            f.Close();
        }
    }
}