using Npgsql;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Ramitta
{
    public partial class PostgreSqlDriver
    {
        private readonly string _connectionString;

        public PostgreSqlDriver(string connectionString)
        {
            _connectionString = connectionString;
        }

        // 执行查询操作，返回查询结果
        public async Task<List<Dictionary<string, object>>> ExecuteQueryAsync(string query, Dictionary<string, object> parameters = null)
        {
            var result = new List<Dictionary<string, object>>();

            using (var conn = new NpgsqlConnection(_connectionString))
            {
                try
                {
                    await conn.OpenAsync();
                    Debug.WriteLine("Database connection established.");

                    using (var cmd = new NpgsqlCommand(query, conn))
                    {
                        if (parameters != null)
                        {
                            foreach (var param in parameters)
                            {
                                cmd.Parameters.AddWithValue(param.Key, param.Value ?? DBNull.Value);
                            }
                        }

                        using (var reader = await cmd.ExecuteReaderAsync())
                        {
                            while (await reader.ReadAsync())
                            {
                                var row = new Dictionary<string, object>();
                                for (int i = 0; i < reader.FieldCount; i++)
                                {
                                    row[reader.GetName(i)] = await reader.IsDBNullAsync(i) ? null : reader.GetValue(i);
                                }
                                result.Add(row);
                            }
                        }
                    }

                    Debug.WriteLine($"Query executed: {query}");
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"Error executing query: {ex.Message}");
                }
            }

            return result;
        }

        // 执行插入、更新、删除操作
        public async Task<int> ExecuteNonQueryAsync(string query, Dictionary<string, object> parameters = null)
        {
            using (var conn = new NpgsqlConnection(_connectionString))
            {
                try
                {
                    await conn.OpenAsync();
                    Debug.WriteLine("Database connection established.");

                    using (var cmd = new NpgsqlCommand(query, conn))
                    {
                        if (parameters != null)
                        {
                            foreach (var param in parameters)
                            {
                                cmd.Parameters.AddWithValue(param.Key, param.Value ?? DBNull.Value);
                            }
                        }

                        var rowsAffected = await cmd.ExecuteNonQueryAsync();
                        Debug.WriteLine($"Executed query: {query}, Rows affected: {rowsAffected}");
                        return rowsAffected;
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"Error executing non-query: {ex.Message}");
                    return -1;
                }
            }
        }

        // 执行插入操作，返回生成的主键
        public async Task<int> ExecuteInsertAsync(string query, Dictionary<string, object> parameters = null, string returnColumn = "id")
        {
            using (var conn = new NpgsqlConnection(_connectionString))
            {
                try
                {
                    await conn.OpenAsync();
                    Debug.WriteLine("Database connection established.");

                    using (var cmd = new NpgsqlCommand(query, conn))
                    {
                        if (parameters != null)
                        {
                            foreach (var param in parameters)
                            {
                                cmd.Parameters.AddWithValue(param.Key, param.Value ?? DBNull.Value);
                            }
                        }

                        cmd.CommandText += $" RETURNING {returnColumn};";

                        var result = await cmd.ExecuteScalarAsync();
                        Debug.WriteLine($"Executed insert, inserted ID: {result}");
                        return result != null ? Convert.ToInt32(result) : -1;
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"Error executing insert: {ex.Message}");
                    return -1;
                }
            }
        }

        // 执行事务操作
        public async Task<bool> ExecuteTransactionAsync(List<string> queries, List<Dictionary<string, object>> parametersList)
        {
            using (var conn = new NpgsqlConnection(_connectionString))
            {
                try
                {
                    await conn.OpenAsync();
                    Debug.WriteLine("Database connection established.");
                    using (var transaction = await conn.BeginTransactionAsync())
                    {
                        for (int i = 0; i < queries.Count; i++)
                        {
                            using (var cmd = new NpgsqlCommand(queries[i], conn, (NpgsqlTransaction)transaction))
                            {
                                var parameters = parametersList[i];
                                if (parameters != null)
                                {
                                    foreach (var param in parameters)
                                    {
                                        cmd.Parameters.AddWithValue(param.Key, param.Value ?? DBNull.Value);
                                    }
                                }

                                await cmd.ExecuteNonQueryAsync();
                            }
                        }

                        await transaction.CommitAsync();
                        Debug.WriteLine("Transaction committed.");
                        return true;
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"Error executing transaction: {ex.Message}");
                    return false;
                }
            }
        }
    }
}