Refactoring and added update fallback.

tldr-sharp/Cache.cs

@@ -0,0 +1,126 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Globalization;
+using System.IO;
+using System.Net;
+using Mono.Data.Sqlite;
+
+namespace tldr_sharp
+{
+    internal static class Cache
+    {
+        private const string Remote = "https://raw.githubusercontent.com/tldr-pages/tldr/master/pages";
+
+        internal static void Check()
+        {
+            if (File.Exists(Program.DbPath)) return;
+
+            Console.WriteLine("Database not found. ");
+            Updater.Update();
+        }
+
+        internal static void CreateSchema()
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+
+                using (SqliteTransaction transaction = conn.BeginTransaction()) 
+                using (var command = new SqliteCommand(conn)) {
+                    command.Transaction = transaction;
+                    command.CommandType = CommandType.Text;
+
+                    command.CommandText =
+                        "CREATE TABLE pages (name VARCHAR(100), platform VARCHAR(10), lang VARCHAR(7), local INTEGER)";
+                    command.ExecuteNonQuery();
+
+                    command.CommandText = "CREATE TABLE config (parameter VARCHAR(20), value VARCHAR(100))";
+                    command.ExecuteNonQuery();
+
+                    command.CommandText = "INSERT INTO config (parameter, value) VALUES(@parameter, @value)";
+                    command.Parameters.AddWithValue("@parameter", "last-update");
+                    command.Parameters.AddWithValue("@value",
+                        DateTime.UtcNow.Date.ToString(CultureInfo.InvariantCulture));
+                    command.ExecuteNonQuery();
+
+                    // Create indexes
+                    command.CommandText = "CREATE INDEX os_names ON pages (platform, name)";
+                    command.ExecuteNonQuery();
+                    command.CommandText = "CREATE INDEX lang_names ON pages (lang, name)";
+                    command.ExecuteNonQuery();
+                    command.CommandText = "CREATE INDEX names_index ON pages (lang, platform, name)";
+                    command.ExecuteNonQuery();
+
+                    transaction.Commit();
+                }
+            }
+        }
+
+        internal static void Clear()
+        {
+            DirectoryInfo cacheDir;
+            try {
+                if (File.Exists(Program.CachePath)) File.Delete(Program.CachePath);
+
+                cacheDir = new DirectoryInfo(Program.CachePath);
+
+                if (cacheDir.Exists) {
+                    cacheDir.Delete(true);
+                }
+            } catch (Exception e) {
+                Console.WriteLine("[ERROR] {0}", e.Message);
+                Environment.Exit(1);
+                return;
+            }
+
+            cacheDir.Create();
+        }
+
+        internal static void DownloadPage(Page page)
+        {
+            var pageFile = new FileInfo(page.GetPath());
+            Directory.CreateDirectory(pageFile.DirectoryName ?? throw new ArgumentException());
+
+            using (var client = new WebClient()) {
+                client.Headers.Add("user-agent", Program.UserAgent);
+
+
+                string language = page.Language == Program.DefaultLanguage ? string.Empty : $".{page.Language}";
+
+                string data = client.DownloadString($"{Remote}{language}/{page.Platform}/{page.Name}.md");
+                using (StreamWriter sw = pageFile.CreateText()) {
+                    sw.WriteLine(data);
+                }
+            }
+
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+                using (SqliteCommand command = conn.CreateCommand()) {
+                    command.CommandText =
+                        "UPDATE pages SET local = TRUE WHERE name = @name AND lang = @lang AND platform = @platform";
+                    command.Parameters.Add(new SqliteParameter("@name", page.Name));
+                    command.Parameters.Add(new SqliteParameter("@platform", page.Platform));
+                    command.Parameters.Add(new SqliteParameter("@lang", page.Language));
+
+                    command.ExecuteNonQuery();
+                }
+            }
+        }
+
+        internal static DateTime LastUpdate()
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+
+                using (var command = new SqliteCommand("SELECT value FROM config WHERE parameter = @parameter", conn)) {
+                    command.Parameters.Add(new SqliteParameter("@parameter", "last-update"));
+
+                    using (SqliteDataReader reader = command.ExecuteReader()) {
+                        reader.Read();
+                        return DateTime.Parse(reader.GetString(0));
+                    }
+                }
+            }
+        }
+    }
+}

tldr-sharp/Index.cs

@@ -0,0 +1,151 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Mono.Data.Sqlite;
+
+namespace tldr_sharp
+{
+    internal static class Index
+    {
+        internal static List<Page> Query(string query, SqliteParameter[] parameters, string page = null)
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+
+                string commandString = page == null
+                    ? $"SELECT name, platform, lang, local FROM pages WHERE {query}"
+                    : $"SELECT platform, lang, local FROM pages WHERE {query}";
+                using (var command = new SqliteCommand(commandString, conn)) {
+                    command.Parameters.AddRange(parameters);
+
+                    using (SqliteDataReader reader = command.ExecuteReader()) {
+                        var results = new List<Page>();
+                        while (reader.Read()) {
+                            if (page == null) {
+                                results.Add(new Page(reader.GetString(0), reader.GetString(1), reader.GetString(2),
+                                    reader.GetBoolean(3)));
+                            } else {
+                                results.Add(new Page(page, reader.GetString(0), reader.GetString(1),
+                                    reader.GetBoolean(2)));
+                            }
+                        }
+
+                        return results;
+                    }
+                }
+            }
+        }
+
+        internal static string GetPlatform()
+        {
+            switch (Environment.OSVersion.Platform) {
+                case PlatformID.MacOSX:
+                    return "osx";
+                case PlatformID.Unix:
+                    return "linux";
+                case PlatformID.Win32NT:
+                case PlatformID.Win32S:
+                case PlatformID.Win32Windows:
+                    return "windows";
+                default:
+                    return "common";
+            }
+        }
+
+
+        internal static IEnumerable<string> ListPlatform()
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+                using (var command = new SqliteCommand("SELECT DISTINCT platform FROM pages", conn)) {
+                    using (SqliteDataReader reader = command.ExecuteReader()) {
+                        SortedSet<string> platform = new SortedSet<string>();
+                        while (reader.Read()) platform.Add(reader.GetString(0));
+
+                        return platform;
+                    }
+                }
+            }
+        }
+
+
+        internal static List<string> GetPreferredLanguages()
+        {
+            var valid = new List<string>();
+            var languages = ListLanguages();
+            if (languages.Contains(Program.Language)) valid.Add(Program.Language);
+
+            Environment.GetEnvironmentVariable("LANGUAGE")
+                ?.Split(':')
+                .Where(x => !x.Equals(string.Empty))
+                .ToList().ForEach(delegate(string s) {
+                    valid.AddRange(languages.Where(l => l.Substring(0, 2).Equals(s)));
+                });
+
+            return valid;
+        }
+
+        internal static List<string> GetEnvLanguages()
+        {
+            var languages = new List<string> {Program.Language};
+            var envs = Environment.GetEnvironmentVariable("LANGUAGE")
+                ?.Split(':')
+                .Where(x => !x.Equals(string.Empty))
+                .ToList();
+            if (envs != null) languages.AddRange(envs);
+            return languages;
+        }
+
+
+        internal static string GetPreferredLanguageOrDefault()
+        {
+            var languages = ListLanguages();
+            if (languages.Contains(Program.Language)) return Program.Language;
+
+            var prefLanguages = Environment.GetEnvironmentVariable("LANGUAGE")
+                ?.Split(':')
+                .Where(x => !x.Equals(string.Empty));
+
+            if (prefLanguages != null) {
+                foreach (string lang in prefLanguages) {
+                    try {
+                        return languages.First(x => x.Substring(0, 2).Equals(lang));
+                    } catch (InvalidOperationException) { }
+                }
+            }
+
+            return Program.DefaultLanguage;
+        }
+
+
+        internal static ICollection<string> ListLanguages()
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+                using (var command = new SqliteCommand("SELECT DISTINCT lang FROM pages", conn)) {
+                    using (SqliteDataReader reader = command.ExecuteReader()) {
+                        var languages = new List<string>();
+                        while (reader.Read()) languages.Add(reader.GetString(0));
+
+                        return languages;
+                    }
+                }
+            }
+        }
+
+
+        internal static bool CheckLanguage(string language)
+        {
+            using (var conn = new SqliteConnection("Data Source=" + Program.DbPath + ";")) {
+                conn.Open();
+                using (var command = new SqliteCommand("SELECT 1 FROM pages WHERE lang = @language", conn)) {
+                    command.Parameters.Add(new SqliteParameter("@language", language));
+
+                    using (SqliteDataReader reader = command.ExecuteReader()) {
+                        return reader.HasRows;
+                    }
+                }
+            }
+        }
+    }
+}