using System.IO;
using System.Text.RegularExpressions;

namespace Housing.Services;

public sealed class LoginSettings
{
    public string Table { get; set; } = "dbo.Housing_Assembly";
    public string IdColumn { get; set; } = "Operator";
    public string PasswordColumn { get; set; } = "Password";
    public bool OfflinePreview { get; set; }

    public static LoginSettings Load(string filePath)
    {
        if (!File.Exists(filePath))
        {
            throw new FileNotFoundException("Database.ini 파일을 찾을 수 없습니다.", filePath);
        }

        var values = IniFile.LoadSection(filePath, "Login");
        return new LoginSettings
        {
            Table = GetString(values, "Table", "dbo.Housing_Assembly"),
            IdColumn = GetString(values, "IdColumn", "Operator"),
            PasswordColumn = GetString(values, "PasswordColumn", "Password"),
            OfflinePreview = GetBool(values, "OfflinePreview", false)
        };
    }

    public string GetQuotedTableName()
    {
        var parts = Table
            .Split('.', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Select(QuoteIdentifier)
            .ToArray();

        if (parts.Length is 0 or > 3)
        {
            throw new InvalidOperationException("Database.ini [Login] Table 값을 확인하세요.");
        }

        return string.Join(".", parts);
    }

    public string GetQuotedIdColumn()
    {
        return QuoteIdentifier(IdColumn);
    }

    public string GetQuotedPasswordColumn()
    {
        return QuoteIdentifier(PasswordColumn);
    }

    private static string GetString(Dictionary<string, string> values, string key, string defaultValue)
    {
        return values.TryGetValue(key, out var value) && !string.IsNullOrWhiteSpace(value)
            ? value.Trim()
            : defaultValue;
    }

    private static bool GetBool(Dictionary<string, string> values, string key, bool defaultValue)
    {
        if (!values.TryGetValue(key, out var value) || string.IsNullOrWhiteSpace(value))
        {
            return defaultValue;
        }

        return value.Trim().ToUpperInvariant() switch
        {
            "1" or "TRUE" or "YES" or "ON" => true,
            "0" or "FALSE" or "NO" or "OFF" => false,
            _ => defaultValue
        };
    }

    private static string QuoteIdentifier(string identifier)
    {
        if (Regex.IsMatch(identifier, @"^[A-Za-z_][A-Za-z0-9_]*$"))
        {
            return $"[{identifier}]";
        }

        throw new InvalidOperationException($"DB 식별자 값이 올바르지 않습니다: {identifier}");
    }
}