using System.Globalization;
using System.Text;
using System.Text.RegularExpressions;
using Housing.Models;

namespace Housing.Services;

public sealed class EquipmentMeasurementService
{
    private readonly EquipmentMeasurementSettings _settings;

    public EquipmentMeasurementService(EquipmentMeasurementSettings settings)
    {
        _settings = settings;
    }

    public async Task<BoardMeasurementResult> ReadAsync()
    {
        var log = new StringBuilder();

        if (_settings.SettleMilliseconds > 0)
        {
            await Task.Delay(_settings.SettleMilliseconds);
        }

        var voltage = await ReadChannelAsync("VOLTAGE", _settings.Voltage, log);
        var current = await ReadChannelAsync("CURRENT", _settings.Current, log);

        return new BoardMeasurementResult
        {
            Voltage = voltage,
            Current = current,
            RawLog = log.ToString()
        };
    }

    private async Task<decimal> ReadChannelAsync(string label, ScpiChannelSettings channel, StringBuilder log)
    {
        if (string.IsNullOrWhiteSpace(channel.ReadCommand))
        {
            throw new InvalidOperationException($"Hardware.ini [Equipment] {label} ReadCommand 값을 확인하세요.");
        }

        using var client = await CreateClientAsync(label, channel);
        log.AppendLine($"> {label} CONNECT: {DescribeClient(client, channel)}");

        if (!string.IsNullOrWhiteSpace(channel.SetupCommand))
        {
            log.AppendLine($"> {label} SETUP: {channel.SetupCommand}");
            await client.SendAsync(channel.SetupCommand);
        }

        log.AppendLine($"> {label} READ: {channel.ReadCommand}");
        var response = await client.QueryAsync(channel.ReadCommand);
        log.AppendLine(response);

        return ExtractFirstDecimal(response, label);
    }

    private Task<IScpiClient> CreateClientAsync(string label, ScpiChannelSettings channel)
    {
        var connection = GetConnectionType(channel);
        return connection switch
        {
            "TCP" or "LAN" => CreateTcpClientAsync(label, channel),
            "SERIAL" or "COM" => Task.FromResult<IScpiClient>(new SerialScpiClient(channel.PortName, channel.BaudRate, _settings.Timeout, channel.GetIdnMatches())),
            "VISA" or "USB" => CreateVisaClientAsync(channel),
            _ => throw new InvalidOperationException($"{label} 장비 연결 방식은 Visa, Serial, Tcp 중 하나로 설정하세요.")
        };
    }

    private static string GetConnectionType(ScpiChannelSettings channel)
    {
        if (!string.IsNullOrWhiteSpace(channel.Connection))
        {
            return channel.Connection.Trim().ToUpperInvariant();
        }

        if (!string.IsNullOrWhiteSpace(channel.ResourceName))
        {
            return "VISA";
        }

        if (!string.IsNullOrWhiteSpace(channel.IdnMatch))
        {
            return "VISA";
        }

        if (!string.IsNullOrWhiteSpace(channel.PortName))
        {
            return "SERIAL";
        }

        if (!string.IsNullOrWhiteSpace(channel.Host))
        {
            return "TCP";
        }

        return string.Empty;
    }

    private async Task<IScpiClient> CreateTcpClientAsync(string label, ScpiChannelSettings channel)
    {
        if (string.IsNullOrWhiteSpace(channel.Host))
        {
            throw new InvalidOperationException($"Hardware.ini [Equipment] {label} Host 값을 확인하세요.");
        }

        return await TcpScpiClient.ConnectAsync(channel.Host, channel.Port, _settings.Timeout);
    }

    private async Task<IScpiClient> CreateVisaClientAsync(ScpiChannelSettings channel)
    {
        return await VisaScpiClient.OpenMatchingAsync(channel.ResourceName, channel.GetIdnMatches(), _settings.Timeout);
    }

    private static string DescribeClient(IScpiClient client, ScpiChannelSettings channel)
    {
        return client switch
        {
            SerialScpiClient serial => $"Serial {serial.PortName} @ {channel.BaudRate}",
            VisaScpiClient visa => $"VISA {visa.ResourceName}",
            TcpScpiClient => $"TCP {channel.Host}:{channel.Port}",
            _ => channel.Connection
        };
    }

    private static decimal ExtractFirstDecimal(string response, string label)
    {
        var match = Regex.Match(response, @"[-+]?\d+(?:\.\d+)?(?:[Ee][-+]?\d+)?");
        if (!match.Success)
        {
            throw new InvalidOperationException($"{label} 측정값 파싱 실패");
        }

        return decimal.Parse(match.Value, NumberStyles.Float, CultureInfo.InvariantCulture);
    }
}