using Evergreen.Health.Application.Health.Devices.Contracts;
using Evergreen.Health.Application.Health.Integrations.HomeAssistant;
using Microsoft.Extensions.Options;

namespace Evergreen.Health.Application.Health.Scenes;

public interface IDeviceActionSafetyRule
{
    Task ValidateAsync(DeviceCommand command, CancellationToken cancellationToken);
    void Accepted(DeviceCommand command, DateTimeOffset now);
}

public sealed class SceneLightSafetyState
{
    private readonly object _lock = new();
    private DateTimeOffset? _offAt;
    public DateTimeOffset? OffAt { get { lock (_lock) return _offAt; } }
    public void MarkOff(DateTimeOffset now) { lock (_lock) _offAt = now; }
    public void MarkOn() { lock (_lock) _offAt = null; }
}

/// <summary>只依赖“启动按摩”的动作意图，不知道床垫实体。防止灯灭后较晚的启动指令再开启按摩。</summary>
public sealed class LightMassageSafetyRule : IDeviceActionSafetyRule
{
    private readonly IHomeAssistantGateway _gateway;
    private readonly string _lightEntity;
    private readonly SceneLightSafetyState _state;
    public LightMassageSafetyRule(IHomeAssistantGateway gateway, IOptions<HomeAssistantOptions> options,
        SceneLightSafetyState state) => (_gateway, _lightEntity, _state) = (gateway, options.Value.Entities.AmbientLight, state);

    public async Task ValidateAsync(DeviceCommand command, CancellationToken cancellationToken)
    {
        if (command.Intent != DeviceCommandIntent.StartMassage || string.IsNullOrWhiteSpace(_lightEntity)) return;
        var light = (await _gateway.GetStatesAsync(cancellationToken)).FirstOrDefault(item =>
            string.Equals(item.EntityId, _lightEntity, StringComparison.OrdinalIgnoreCase));
        var offAt = _state.OffAt;
        if (light is null || !DeviceActionRunner.IsAvailable(light) ||
            !string.Equals(light.State, "on", StringComparison.OrdinalIgnoreCase) ||
            light.GetDoubleAttribute("brightness") is <= 0 ||
            (offAt is not null && (light.LastUpdated is null || light.LastUpdated <= offAt)))
            throw new InvalidOperationException("卧室灯光已关闭或状态未确认，不启动床垫按摩");
    }

    public void Accepted(DeviceCommand command, DateTimeOffset now)
    {
        if (command.Intent == DeviceCommandIntent.TurnRelaxationLightOff) _state.MarkOff(now);
        else if (command.Intent == DeviceCommandIntent.TurnRelaxationLightOn) _state.MarkOn();
    }
}