using ClawdDotNet.Core.Accounting;
using ClawdDotNet.Core.Config;
using ClawdDotNet.Core.Deploymentcenter.Watchdog;
using Shouldly;

namespace ClawdDotNet.Core.Tests.Deploymentcenter;

public sealed class InstanceHealthProviderTests
{
    /// <summary>Delivers a fixed daily consumption, without a DB.</summary>
    private sealed class FakeUsage(DailyUsage daily) : IUsageRepository
    {
        public Task RecordAsync(RunUsage usage, CancellationToken ct) => Task.CompletedTask;

        public Task<DailyUsage> GetDailyAsync(DateOnly date, string agentId, CancellationToken ct)
            => Task.FromResult(daily);

        public Task<IReadOnlyList<RunUsage>> GetRecentAsync(int limit, CancellationToken ct)
            => Task.FromResult((IReadOnlyList<RunUsage>)Array.Empty<RunUsage>());

        public Task<int> PurgeBeforeAsync(DateOnly date, CancellationToken ct) => Task.FromResult(0);
    }

    private static DailyUsage Usage(decimal cost, int tokens = 0) =>
        new(DateOnly.FromDateTime(DateTime.Now), tokens, 0, cost, true, 1);

    [Fact]
    public async Task Without_API_key_reports_error()
    {
        var provider = new InstanceHealthProvider(
            "Test", agentsEnabled: false, InstanceBudget.Unlimited,
            usage: null, () => 2, () => 0);

        var health = await provider.GetAsync(default);

        health.Status.ShouldBe(WatchdogStatus.Error);
        health.Metrics["agentCount"].ShouldBe(2);
        health.Checks["agents"].Ok.ShouldBeFalse();
    }

    [Fact]
    public async Task Exhausted_cost_budget_reports_warning()
    {
        var budget = new InstanceBudget { DailyCostUsd = 5m };
        var provider = new InstanceHealthProvider(
            "Test", agentsEnabled: true, budget,
            new FakeUsage(Usage(cost: 5m)), () => 1, () => 0);

        var health = await provider.GetAsync(default);

        health.Status.ShouldBe(WatchdogStatus.Warning);
        health.Checks["budget"].Ok.ShouldBeFalse();
        health.Message.ShouldNotBeNull();
    }

    /// <summary>
    /// A heartbeat only proves that a thread is running. If the scanner stands still, the
    /// instance no longer works through anything — and exactly that is what the check should make visible.
    /// </summary>
    [Fact]
    public async Task Stalled_scanner_reports_warning()
    {
        var provider = new InstanceHealthProvider(
            "Test", agentsEnabled: true, InstanceBudget.Unlimited,
            new FakeUsage(Usage(cost: 0m)), () => 1, () => 0,
            schedulerRunning: () => false);

        var health = await provider.GetAsync(default);

        health.Status.ShouldBe(WatchdogStatus.Warning);
        health.Checks["scheduler"].Ok.ShouldBeFalse();
    }

    [Fact]
    public async Task Normal_operation_reports_ok_with_metrics()
    {
        var provider = new InstanceHealthProvider(
            "Test", agentsEnabled: true, InstanceBudget.Unlimited,
            new FakeUsage(Usage(cost: 0.5m, tokens: 1200)), () => 3, () => 1,
            schedulerRunning: () => true);

        var health = await provider.GetAsync(default);

        health.Status.ShouldBe(WatchdogStatus.Ok);
        health.Metrics["runningChats"].ShouldBe(1);
        health.Metrics.Keys.ShouldContain("todayCostUsd");
        health.Metrics.Keys.ShouldContain("todayTokens");
        health.Checks.Values.ShouldAllBe(c => c.Ok);
    }

    /// <summary>
    /// Metrics are only evaluated server-side if they are numbers — everything else
    /// the history silently discards. Descriptive things belong in the message.
    /// </summary>
    [Fact]
    public async Task Instance_name_is_in_the_message_not_in_the_metrics()
    {
        var provider = new InstanceHealthProvider(
            "Produktion", agentsEnabled: true, InstanceBudget.Unlimited,
            usage: null, () => 1, () => 0);

        var health = await provider.GetAsync(default);

        health.Message.ShouldNotBeNull().ShouldContain("Produktion");
        health.Metrics.Keys.ShouldNotContain("instanceName");
    }
}