using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using ChaosBot.Database;
using Microsoft.Data.Sqlite;
using NLog;

namespace ChaosBot.Attribute
{
    public static class AssemblyController
    {
        private static Logger _logger = Program._logger;
        public static void Register()
        {
            Assembly dbEntityAssembly = Assembly.GetAssembly(typeof(DBEntity));
            if (dbEntityAssembly != null)
            {
                foreach (Type type in dbEntityAssembly.GetTypes())
                {
                    if (type.GetCustomAttributes(typeof(DBEntity), true).Length > 0)
                    {
                        // type == all classes that have [DBEntity(...)]
                        
                        // Get a reference to the attribute
                        DBEntity dbEntity = type.GetCustomAttributes(typeof(DBEntity)).Cast<DBEntity>().First();

                        string table = dbEntity.Table;
                        // TODO: Generate this in one go instead of many separate commands
                        Controller.RawQuery($"CREATE TABLE IF NOT EXISTS {table} (id INTEGER NOT NULL CONSTRAINT {table}_pk PRIMARY KEY AUTOINCREMENT)");
                        
                        foreach (MethodInfo field in type.GetMethods())
                        {
                            if (field.Name.StartsWith("get_"))
                            {
                                try
                                {
                                    // TODO: Use an attribute to detect primary autoincrement key
                                    if (field.Name == "id")
                                    {
                                        Controller.RawQuery($"CREATE UNIQUE INDEX {table}_id_uindex ON {table} (id)", false, true);
                                        continue;
                                    }
                                    
                                    string fieldname = field.Name.Substring(4);
                                    string fieldType = DBEntity.DataTypes.GetValueOrDefault(field.ReturnType).ToString();
                                    string fieldModifiers = null;

                                    string query = $"ALTER TABLE {table} ADD COLUMN {fieldname} {fieldType} {fieldModifiers}";
                                    Controller.RawQuery(query, false, true);
                                }
                                catch (Exception ex)
                                {
                                    if (ex is SqliteException sqliteException)
                                    {
                                        if (!sqliteException.Message.Contains("duplicate column name"))
                                        {
                                            _logger.Fatal($"AssemblyController.Register: Exception [{ex}] thrown, <[{ex.Message}]>.");
                                        }
                                    }
                                    else
                                    {
                                        _logger.Error($"AssemblyController.Register: Exception [{ex}] thrown, <[{ex.Message}]>.");
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}