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

namespace Housing.Services;

public sealed class BoardTestService
{
    private readonly BoardHardwareSettings _boardSettings;
    private readonly EquipmentMeasurementSettings _equipmentSettings;

    public BoardTestService(BoardHardwareSettings boardSettings, EquipmentMeasurementSettings equipmentSettings)
    {
        _boardSettings = boardSettings;
        _equipmentSettings = equipmentSettings;
    }

    public async Task<BoardMeasurementResult> RunAsync(
        Func<string, Task>? onIcSnReadAsync = null,
        DateTime? measurementNotBeforeUtc = null)
    {
        var log = new StringBuilder();
        var equipmentService = new EquipmentMeasurementService(_equipmentSettings);

        log.Append(await equipmentService.RunPreBoardCommandAsync());
        if (_equipmentSettings.PreBoardDelayMilliseconds > 0)
        {
            log.AppendLine($"> CURRENT PRE-BOARD DELAY: {_equipmentSettings.PreBoardDelayMilliseconds} ms");
            await Task.Delay(_equipmentSettings.PreBoardDelayMilliseconds);
        }

        using var boardClient = new SerialBoardClient(_boardSettings);
        log.AppendLine($"> BOARD PORT: {boardClient.PortName} @ {_boardSettings.BaudRate}");

        await SendOnlyAndLogAsync(boardClient, "PRE_CONNECT", _boardSettings.PreConnectCommand, log);

        var connectResponse = await SendAndLogAsync(boardClient, "CONNECT", _boardSettings.ConnectCommand, _boardSettings.ReadTimeout, true, log);
        if (!ContainsSuccess(connectResponse))
        {
            throw new InvalidOperationException("시료 연결 확인 실패");
        }

        var idResponse = await SendAndLogAsync(boardClient, "READ_ID", _boardSettings.ReadIdCommand, _boardSettings.ReadTimeout, true, log);
        var icSn = ExtractFirstHexLine(idResponse);
        if (string.IsNullOrWhiteSpace(icSn))
        {
            throw new InvalidOperationException("IC_SN 읽기 실패");
        }

        await SendOnlyAndLogAsync(boardClient, "POST_READ_ID", _boardSettings.PostReadIdCommand, log);

        if (onIcSnReadAsync is not null)
        {
            await onIcSnReadAsync(icSn);
        }

        await SendAndLogAsync(boardClient, "CAL_DEFAULT", _boardSettings.CalDefaultCommand, _boardSettings.ReadTimeout, false, log);

        if (measurementNotBeforeUtc.HasValue)
        {
            var remainingDelay = measurementNotBeforeUtc.Value - DateTime.UtcNow;
            if (remainingDelay > TimeSpan.Zero)
            {
                log.AppendLine($"> MEASUREMENT START DELAY: {(int)remainingDelay.TotalMilliseconds} ms");
                await Task.Delay(remainingDelay);
            }
        }

        var equipmentResult = await equipmentService.ReadAsync();
        log.Append(equipmentResult.RawLog);

        return new BoardMeasurementResult
        {
            IcSn = icSn,
            Voltage = equipmentResult.Voltage,
            Current = equipmentResult.Current,
            RawLog = log.ToString()
        };
    }

    private static async Task<string> SendAndLogAsync(
        SerialBoardClient client,
        string label,
        string command,
        int timeoutMilliseconds,
        bool waitForEndToken,
        StringBuilder log)
    {
        log.AppendLine($"> BOARD {label}: {command}");
        var response = await client.SendCommandAsync(command, timeoutMilliseconds, waitForEndToken);
        log.Append(response);
        return response;
    }

    private static async Task SendOnlyAndLogAsync(
        SerialBoardClient client,
        string label,
        string command,
        StringBuilder log)
    {
        if (string.IsNullOrWhiteSpace(command))
        {
            return;
        }

        log.AppendLine($"> BOARD {label}: {command}");
        await client.SendOnlyAsync(command);
    }

    private static bool ContainsSuccess(string response)
    {
        return response
            .Split(new[] { "\r\n", "\n" }, StringSplitOptions.RemoveEmptyEntries)
            .Any(line => string.Equals(line.Trim(), "Success", StringComparison.OrdinalIgnoreCase));
    }

    private static string ExtractFirstHexLine(string response)
    {
        foreach (var rawLine in response.Split(new[] { "\r\n", "\n" }, StringSplitOptions.RemoveEmptyEntries))
        {
            var line = rawLine.Trim();
            if (line.Equals("<end>", StringComparison.OrdinalIgnoreCase) ||
                line.Equals("Fail", StringComparison.OrdinalIgnoreCase))
            {
                continue;
            }

            if (Regex.IsMatch(line, "^[0-9A-Fa-f]{8,32}$"))
            {
                return line.ToUpperInvariant();
            }
        }

        return string.Empty;
    }
}