using MeetingAssistant.Calendar;
using MeetingAssistant.Recording;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;

namespace MeetingAssistant.Tests;

public sealed class CalendarRecordingPromptSchedulerTests
{
    [Fact]
    public async Task DueTeamsMeetingPromptStartsRecordingWhenAccepted()
    {
        var harness = CreateHarness(isRecording: false);
        var meeting = CreateMeeting(harness.Clock);
        harness.Provider.Meetings = [meeting];

        await SyncThenPromptAsync(harness, meeting);

        Assert.Equal(1, harness.Provider.QueryCount);
        Assert.Collection(harness.PromptService.PromptedMeetings, prompted => Assert.Same(meeting, prompted));
        Assert.Equal(1, harness.Recorder.StartCount);
        Assert.Equal(0, harness.Recorder.StopCount);
    }

    [Fact]
    public async Task AcceptedPromptStopsActiveRecordingBeforeStartingNewRecording()
    {
        var harness = CreateHarness(isRecording: true);
        var meeting = CreateMeeting(harness.Clock);
        harness.Provider.Meetings = [meeting];

        await SyncThenPromptAsync(harness, meeting);

        Assert.Equal(["stop", "start"], harness.Recorder.Commands);
    }

    [Fact]
    public async Task DisabledCalendarPromptsDoNotQueryCalendar()
    {
        var harness = CreateHarness(enabled: false);

        await harness.Scheduler.SyncOnceAsync(CancellationToken.None);

        Assert.Equal(0, harness.Provider.QueryCount);
    }

    [Fact]
    public async Task DueMeetingPromptsOnlyOncePerDay()
    {
        var harness = CreateHarness();
        var meeting = CreateMeeting(harness.Clock);
        harness.Provider.Meetings = [meeting];

        await harness.Scheduler.SyncOnceAsync(CancellationToken.None);
        harness.Clock.Now = meeting.Start;
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);

        Assert.Single(harness.PromptService.PromptedMeetings);
    }

    [Fact]
    public async Task CachedMeetingPromptDoesNotQueryOutlookAgainAtMeetingStart()
    {
        var harness = CreateHarness();
        var meeting = CreateMeeting(harness.Clock);
        harness.Provider.Meetings = [meeting];

        await SyncThenPromptAsync(harness, meeting);

        Assert.Equal(1, harness.Provider.QueryCount);
        Assert.Single(harness.PromptService.PromptedMeetings);
    }

    [Fact]
    public async Task CachedDayMeetingsPromptBackToBackMeetingsWithoutInterveningOutlookSync()
    {
        var harness = CreateHarness(isRecording: false);
        var firstMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-1",
            subject: "First sync",
            startOffset: TimeSpan.FromMinutes(30),
            duration: TimeSpan.FromMinutes(10));
        var secondMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-2",
            subject: "Second sync",
            startOffset: TimeSpan.FromMinutes(40),
            duration: TimeSpan.FromMinutes(10));
        harness.Provider.Meetings = [firstMeeting, secondMeeting];

        await harness.Scheduler.SyncOnceAsync(CancellationToken.None);
        harness.Clock.Now = firstMeeting.Start;
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);
        harness.Clock.Now = secondMeeting.Start;
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);

        Assert.Equal(1, harness.Provider.QueryCount);
        Assert.Equal([firstMeeting, secondMeeting], harness.PromptService.PromptedMeetings);
        Assert.Equal(["start", "stop", "start"], harness.Recorder.Commands);
    }

    private static async Task SyncThenPromptAsync(
        SchedulerHarness harness,
        CalendarMeeting meeting)
    {
        await harness.Scheduler.SyncOnceAsync(CancellationToken.None);
        harness.Clock.Now = meeting.Start;
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);
    }

    private static CalendarMeeting CreateMeeting(
        ManualCalendarPromptClock clock,
        string id = "teams-1",
        string subject = "Project sync",
        TimeSpan? startOffset = null,
        TimeSpan? duration = null)
    {
        var start = clock.Now.Add(startOffset ?? TimeSpan.FromMinutes(30));
        return new CalendarMeeting(
            id,
            subject,
            start,
            start.Add(duration ?? TimeSpan.FromMinutes(30)));
    }

    private static SchedulerHarness CreateHarness(
        bool isRecording = false,
        bool enabled = true)
    {
        var clock = new ManualCalendarPromptClock(new DateTimeOffset(2026, 6, 3, 9, 30, 0, TimeSpan.Zero));
        var provider = new RecordingCalendarMeetingProvider([]);
        var promptService = new AcceptingMeetingStartPromptService();
        var recorder = new RecordingPromptRecorder(isRecording);
        var scheduler = new CalendarRecordingPromptScheduler(
            Options.Create(new MeetingAssistantOptions
            {
                CalendarRecordingPrompts =
                {
                    Enabled = enabled,
                    SyncInterval = TimeSpan.FromMinutes(30),
                    PromptWindow = TimeSpan.FromMinutes(5)
                }
            }),
            provider,
            promptService,
            recorder,
            clock,
            NullLogger<CalendarRecordingPromptScheduler>.Instance);

        return new SchedulerHarness(scheduler, provider, promptService, recorder, clock);
    }

    private sealed record SchedulerHarness(
        CalendarRecordingPromptScheduler Scheduler,
        RecordingCalendarMeetingProvider Provider,
        AcceptingMeetingStartPromptService PromptService,
        RecordingPromptRecorder Recorder,
        ManualCalendarPromptClock Clock);

    private sealed class RecordingCalendarMeetingProvider : ICalendarMeetingProvider
    {
        public RecordingCalendarMeetingProvider(IReadOnlyList<CalendarMeeting> meetings)
        {
            Meetings = meetings;
        }

        public IReadOnlyList<CalendarMeeting> Meetings { get; set; }

        public int QueryCount { get; private set; }

        public Task<IReadOnlyList<CalendarMeeting>> GetRecordingPromptCandidatesForDayAsync(
            DateOnly day,
            CancellationToken cancellationToken)
        {
            QueryCount++;
            return Task.FromResult(Meetings);
        }
    }

    private sealed class AcceptingMeetingStartPromptService : IMeetingStartPromptService
    {
        public List<CalendarMeeting> PromptedMeetings { get; } = [];

        public async Task ShowPromptAsync(
            MeetingStartPromptRequest request,
            Func<MeetingStartPromptResponse, CancellationToken, Task> handleResponseAsync,
            CancellationToken cancellationToken)
        {
            PromptedMeetings.Add(request.Meeting);
            await handleResponseAsync(MeetingStartPromptResponse.Record, cancellationToken);
        }
    }

    private sealed class RecordingPromptRecorder : IMeetingPromptRecordingController
    {
        public RecordingPromptRecorder(bool isRecording)
        {
            CurrentStatus = Status(isRecording);
        }

        public RecordingStatus CurrentStatus { get; private set; }

        public int StartCount { get; private set; }

        public int StopCount { get; private set; }

        public List<string> Commands { get; } = [];

        public Task<RecordingStatus> StartAsync(CancellationToken cancellationToken)
        {
            StartCount++;
            Commands.Add("start");
            CurrentStatus = Status(isRecording: true);
            return Task.FromResult(CurrentStatus);
        }

        public Task<RecordingStatus> StopAsync(CancellationToken cancellationToken)
        {
            StopCount++;
            Commands.Add("stop");
            CurrentStatus = Status(isRecording: false);
            return Task.FromResult(CurrentStatus);
        }

        private static RecordingStatus Status(bool isRecording)
        {
            return new RecordingStatus(
                isRecording,
                isRecording ? "transcript.md" : null,
                isRecording ? "meeting.md" : null,
                isRecording ? "context.md" : null,
                isRecording ? "summary.md" : null,
                isRecording ? RecordingProcessState.Recording : RecordingProcessState.Idle,
                isRecording ? "default" : null);
        }
    }

    private sealed class ManualCalendarPromptClock : ICalendarPromptClock
    {
        public ManualCalendarPromptClock(DateTimeOffset now)
        {
            Now = now;
        }

        public DateTimeOffset Now { get; set; }
    }
}