using System.Text.RegularExpressions;
using Cloud;
using DatabaseTest.Models;
using Microsoft.EntityFrameworkCore;
using Npgsql;

namespace DatabaseTest.Services;

public interface IDatabaseConfigService
{
    DatabaseProviderType ProviderType { get; }
    string ConnectionString { get; }
    string InMemoryDbName { get; }
    event Action? OnConfigurationChanged;

    void SetProvider(DatabaseProviderType providerType);
    void SetConnectionString(string connectionString);
    void SetInMemoryDbName(string name);
    AppDbContext CreateDbContext();
    string GetActiveProviderDescription();
}

public class DatabaseConfigService : IDatabaseConfigService
{
    private readonly IConfiguration _configuration;

    public DatabaseConfigService(IConfiguration configuration)
    {
        _configuration = configuration;

        var envPassword = Environment.GetEnvironmentVariable("PostgreSQL_Password")
                          ?? (OperatingSystem.IsWindows()
                              ? Environment.GetEnvironmentVariable("PostgreSQL_Password",
                                  EnvironmentVariableTarget.User)
                              : null)
                          ?? (OperatingSystem.IsWindows()
                              ? Environment.GetEnvironmentVariable("PostgreSQL_Password",
                                  EnvironmentVariableTarget.Machine)
                              : null)
                          ?? Environment.GetEnvironmentVariable("POSTGRESQL_PASSWORD")
                          ?? Environment.GetEnvironmentVariable("POSTGRES_PASSWORD");

        var configuredConn = _configuration.GetConnectionString("DefaultConnection")
                             ?? _configuration.GetConnectionString("Postgres")
                             ?? Environment.GetEnvironmentVariable("POSTGRES_CONNECTION_STRING");

        if (string.IsNullOrWhiteSpace(configuredConn))
        {
            var csb = new NpgsqlConnectionStringBuilder
            {
                Host = "localhost",
                Database = "chrono",
                Username = "postgres",
                Password = envPassword
            };
            configuredConn = csb.ConnectionString;
        }
        else if (!string.IsNullOrEmpty(envPassword))
        {
            try
            {
                var csb = new NpgsqlConnectionStringBuilder(configuredConn)
                {
                    Password = envPassword
                };
                configuredConn = csb.ConnectionString;
            }
            catch
            {
            }
        }

        ConnectionString = configuredConn;
        ProviderType = DatabaseProviderType.PostgreSQL;
    }

    public event Action? OnConfigurationChanged;

    public DatabaseProviderType ProviderType { get; private set; }

    public string ConnectionString { get; private set; }

    public string InMemoryDbName { get; private set; } = "chrono_database_test";

    public void SetProvider(DatabaseProviderType providerType)
    {
        if (ProviderType != providerType)
        {
            ProviderType = providerType;
            OnConfigurationChanged?.Invoke();
        }
    }

    public void SetConnectionString(string connectionString)
    {
        if (ConnectionString != connectionString)
        {
            ConnectionString = connectionString;
            OnConfigurationChanged?.Invoke();
        }
    }

    public void SetInMemoryDbName(string name)
    {
        if (InMemoryDbName != name)
        {
            InMemoryDbName = name;
            OnConfigurationChanged?.Invoke();
        }
    }

    public string GetActiveProviderDescription()
    {
        return ProviderType switch
        {
            DatabaseProviderType.PostgreSQL => $"PostgreSQL ({GetMaskedConnectionString(ConnectionString)})",
            DatabaseProviderType.InMemory => $"In-Memory Test Database ({InMemoryDbName})",
            _ => ProviderType.ToString()
        };
    }

    public AppDbContext CreateDbContext()
    {
        var builder = new DbContextOptionsBuilder<AppDbContext>();

        if (ProviderType == DatabaseProviderType.PostgreSQL)
            builder.UseNpgsql(ConnectionString, npgsqlOptions => { npgsqlOptions.CommandTimeout(15); });
        else
            builder.UseInMemoryDatabase(InMemoryDbName);

        return new AppDbContext(builder.Options);
    }

    private static string GetMaskedConnectionString(string conn)
    {
        if (string.IsNullOrWhiteSpace(conn)) return "Not configured";
        // Hide password in display
        return Regex.Replace(conn, @"(?i)Password=[^;]+", "Password=******");
    }
}