Add shared packages

src/Tribufu.Database/DatabaseConfiguration.cs

@@ -0,0 +1,55 @@
+// Copyright (c) Tribufu. All Rights Reserved.
+// SPDX-License-Identifier: MIT
+
+using Microsoft.Extensions.Configuration;
+using System;
+
+namespace Tribufu.Database
+{
+    public class DatabaseConfiguration
+    {
+        public DatabaseDriver Driver { get; set; }
+
+        public string? Version { get; set; }
+
+        public string? Host { get; set; }
+
+        public string? Port { get; set; }
+
+        public string? User { get; set; }
+
+        public string? Password { get; set; }
+
+        public string? Schema { get; set; }
+
+        /// <summary>
+        /// Loads the <see cref="DatabaseConfiguration"/> from the "database" section or from root-level keys prefixed with "database_".
+        /// </summary>
+        /// <param name="configuration">The configuration source.</param>
+        /// <returns>The populated <see cref="DatabaseConfiguration"/> instance.</returns>
+        public static DatabaseConfiguration Load(IConfiguration configuration)
+        {
+            var section = configuration.GetSection("database");
+            var useRootFallback = !section.Exists();
+
+            string? GetConfig(string key) => useRootFallback ? configuration[$"database_{key}"] : section[key];
+
+            var driverString = GetConfig("driver") ?? throw new Exception("Missing database driver");
+            if (!Enum.TryParse<DatabaseDriver>(driverString, true, out var driver))
+            {
+                throw new Exception($"Unsupported database driver: {driverString}");
+            }
+
+            return new DatabaseConfiguration
+            {
+                Driver = driver,
+                Version = GetConfig("version"),
+                Host = GetConfig("host"),
+                Port = GetConfig("port"),
+                User = GetConfig("user"),
+                Password = GetConfig("password"),
+                Schema = GetConfig("schema")
+            };
+        }
+    }
+}