using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using Antlr4.Runtime;
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)
                    {
                        // Get a reference to the attribute
                        DBEntity dbEntity = type.GetCustomAttributes(typeof(DBEntity)).Cast<DBEntity>().First();
                        
                        // Generate columns
                        // name, type, constraintName, constraints, 
                        List<Tuple<string, string, string, string>> columnList = new List<Tuple<string, string, string, string>>();
                            
                        // Get the table as an easy variable
                        string table = dbEntity.Table;

                        // Loop through all fields
                        foreach (PropertyInfo prop in type.GetProperties())
                        {
                            string columnName = prop.Name;
                            string columnType = DBEntity.DataTypes.GetValueOrDefault(prop.PropertyType).ToString();
                            StringBuilder constraintNameBuilder = new StringBuilder($"{table}_{columnName}");
                            List<string> constraintsList = new List<string>();

                            // Go through every attribute
                            foreach (object fieldAttribute in prop.GetCustomAttributes(true))
                            {
                                if (fieldAttribute is DBFieldAttribute dBFieldAttribute)
                                {
                                    string constraintSuffix =
                                        DBEntity.ConstrainNames.GetValueOrDefault(dBFieldAttribute.GetType(), null);
                                    if (constraintSuffix != null)
                                    {
                                        constraintNameBuilder.Append($"_{constraintSuffix}");
                                        constraintsList.Add($"{dBFieldAttribute.GetSQLiteQuery()}");
                                    }
                                }
                            }

                            string constraintName = constraintNameBuilder.ToString();
                            if (constraintsList.Count > 0)
                            {
                                constraintsList.Insert(0, "CONSTRAINT");
                                constraintsList.Insert(1, constraintName);
                            }
                            string constraints = String.Join(" ", constraintsList);
                            columnList.Add(new Tuple<string, string, string, string>(columnName, columnType, constraintName, constraints));
                        }
                        
                        // Check table exists
                        bool tableExists =
                            Controller.RawQuery($"SELECT name FROM sqlite_master WHERE type='table' AND name='{table}'")
                                .Rows.Count > 0;

                        try
                        {
                            if (!tableExists)
                            {
                                string columnDefs = String.Join(", ", columnList.Select(c => $"{c.Item1} {c.Item2} {c.Item4}"));
                                string query = $"CREATE TABLE {table} ({columnDefs})";
                                Controller.RawQuery(query);
                            }
                            // // TODO: Generate this in one go instead of many separate commands
                            // Controller.RawQuery($"CREATE TABLE IF NOT EXISTS {table} (id INTEGER NOT NULL CONSTRAINT {table}_pk PRIMARY KEY AUTOINCREMENT)");
                            // Controller.RawQuery($"CREATE UNIQUE INDEX {table}_id_uindex ON {table} (id)", false, true);
                            // string query = $"ALTER TABLE {table} ADD COLUMN {fieldname} {fieldType} {fieldModifiers}";
                        }
                        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}]>.");
                            }
                        }
                    }
                }
            }
        }
    }
}