using Fleet.Core;
using Fleet.Server;
using Microsoft.Extensions.DependencyInjection;
using MoShiro.Backend.Application;
using MoShiro.Protocol;

namespace MoShiro.Backend.Gateway;

/// <summary>
/// Application 通往 Agent 连接的端口的实现，建立在 Fleet.Server.Link 的在线表之上。
/// Fleet 的连接宿主依赖节点事件处理器，而事件处理器依赖 Application，Application 又依赖这个端口：
/// 这里在调用时才解析 Fleet 的服务，打断构造期的循环依赖。
/// </summary>
public sealed class FleetGateway : IAgentGateway
{
    private readonly IServiceProvider _services;

    public FleetGateway(IServiceProvider services)
    {
        _services = services;
    }

    private IFleetConnections Connections => _services.GetRequiredService<IFleetConnections>();

    private IStateNotifier Notifier => _services.GetRequiredService<IStateNotifier>();

    public IReadOnlyCollection<NodeId> OnlineAgents => [.. Connections.OnlineNodes.Where(n => n.Value.StartsWith(AgentIds.Prefix, StringComparison.Ordinal))];

    public IReadOnlyCollection<NodeId> OnlineNodes => Connections.OnlineNodes;

    public bool IsOnline(NodeId agent) => Connections.IsOnline(agent);

    public void NotifyTaskSetChanged(NodeId agent) => Notifier.NotifyChanged(agent);

    public void NotifyAllTaskSetsChanged() => Notifier.NotifyAllChanged();

    public async ValueTask<Result<bool>> RunTestAsync(NodeId agent, TestRunParams run, CancellationToken ct)
    {
        Result<TestRunResult> result = await Connections.RequestAsync(
            agent, MoShiroMethods.TestRun, run, MoShiroJsonContext.Default.TestRunParams, MoShiroJsonContext.Default.TestRunResult, ct);
        if (!result.TryGet(out TestRunResult? accepted, out FleetError? error))
        {
            return Result<bool>.Fail(error.Code == FleetErrors.NodeOffline ? MoShiroErrors.AgentOffline : error.Code, error.Message);
        }

        return accepted.Accepted ? Result<bool>.Ok(true) : Result<bool>.Fail(MoShiroErrors.TestBusy, "the agent did not accept the test");
    }

    public async ValueTask CancelTestAsync(NodeId agent, TestId test, CancellationToken ct) =>
        await Connections.RequestAsync(
            agent, MoShiroMethods.TestCancel, new TestCancelParams { TestId = test }, MoShiroJsonContext.Default.TestCancelParams, MoShiroJsonContext.Default.TestRunResult, ct);

    public async ValueTask<Result<bool>> DisconnectDialerAsync(NodeId listener, NodeId dialer, CancellationToken ct)
    {
        Result<TestRunResult> result = await Connections.RequestAsync(
            listener, MoShiroMethods.DialerDisconnect, new DialerDisconnectParams { DialerId = dialer }, MoShiroJsonContext.Default.DialerDisconnectParams, MoShiroJsonContext.Default.TestRunResult, ct);
        if (!result.TryGet(out TestRunResult? done, out FleetError? error))
        {
            return Result<bool>.Fail(error.Code == FleetErrors.NodeOffline ? MoShiroErrors.AgentOffline : error.Code, error.Message);
        }

        return Result<bool>.Ok(done.Accepted);
    }

    public ValueTask DisconnectAsync(NodeId agent, string reason, CancellationToken ct) => Connections.DisconnectAsync(agent, reason, ct);

    public ValueTask<bool> NotifyLinkRetryAsync(NodeId dialer, NodeId listener, CancellationToken ct) =>
        Connections.NotifyAsync(dialer, MoShiroMethods.LinkRetry, new LinkRetryParams { ListenerId = listener }, MoShiroJsonContext.Default.LinkRetryParams, ct);

    public async ValueTask NotifyUpdateOfferAsync(NodeId node, string manifest, string signature, CancellationToken ct) =>
        await Connections.NotifyAsync(node, MoShiroMethods.UpdateOffer, new UpdateOfferParams { Manifest = manifest, Signature = signature }, MoShiroJsonContext.Default.UpdateOfferParams, ct);

    public async ValueTask NotifyScheduleAsync(NodeId node, string? restartAt, CancellationToken ct) =>
        await Connections.NotifyAsync(node, MoShiroMethods.Schedule, new ScheduleParams { RestartAt = restartAt }, MoShiroJsonContext.Default.ScheduleParams, ct);

    public async ValueTask<bool> NotifyUpdateApplyAsync(NodeId node, CancellationToken ct) =>
        await Connections.NotifyAsync(node, MoShiroMethods.UpdateApply, new UpdateOfferParams(), MoShiroJsonContext.Default.UpdateOfferParams, ct);
}