using MeetingAssistant.Calendar;
using MeetingAssistant.MeetingNotes;
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 AcceptedPromptStartsRecordingWithPromptedMeetingMetadata()
    {
        var harness = CreateHarness(isRecording: false);
        var selectedMetadata = new MeetingMetadata(
            "Selected planning",
            ["Ada"],
            "Selected agenda",
            DateTimeOffset.Parse("2026-06-03T10:30:00+00:00"));
        var otherMetadata = new MeetingMetadata(
            "Other planning",
            ["Grace"],
            "Other agenda",
            DateTimeOffset.Parse("2026-06-03T10:40:00+00:00"));
        var selectedMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-selected",
            subject: "Selected planning",
            metadata: selectedMetadata);
        var otherMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-other",
            subject: "Other planning",
            startOffset: TimeSpan.FromMinutes(40),
            metadata: otherMetadata);
        harness.Provider.Meetings = [selectedMeeting, otherMeeting];

        await SyncThenPromptAsync(harness, selectedMeeting);

        Assert.Equal(1, harness.Recorder.StartCount);
        Assert.Same(selectedMetadata, harness.Recorder.StartMetadata.Single());
        Assert.Equal(1, harness.Recorder.PromptStartCount);
    }

    [Fact]
    public async Task AcceptedPromptWithoutMetadataStillUsesPromptStartPath()
    {
        var harness = CreateHarness(isRecording: false);
        var meeting = CreateMeeting(
            harness.Clock,
            id: "teams-without-metadata",
            subject: "No metadata",
            metadata: null);
        harness.Provider.Meetings = [meeting];

        await SyncThenPromptAsync(harness, meeting);

        Assert.Equal(1, harness.Recorder.StartCount);
        Assert.Null(harness.Recorder.StartMetadata.Single());
        Assert.Equal(1, harness.Recorder.PromptStartCount);
    }

    [Fact]
    public async Task AcceptingDisplayedPromptsOutOfOrderUsesAcceptedPromptMetadata()
    {
        var harness = CreateHarness(isRecording: false, autoAcceptPrompts: false);
        var firstMetadata = new MeetingMetadata(
            "First planning",
            ["Ada"],
            "First agenda",
            DateTimeOffset.Parse("2026-06-03T10:30:00+00:00"));
        var secondMetadata = new MeetingMetadata(
            "Second planning",
            ["Grace"],
            "Second agenda",
            DateTimeOffset.Parse("2026-06-03T10:30:00+00:00"));
        var firstMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-first",
            subject: "First planning",
            metadata: firstMetadata);
        var secondMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-second",
            subject: "Second planning",
            metadata: secondMetadata);
        harness.Provider.Meetings = [firstMeeting, secondMeeting];

        await harness.Scheduler.SyncOnceAsync(CancellationToken.None);
        harness.Clock.Now = firstMeeting.Start;
        await harness.Scheduler.CheckDuePromptsAsync(CancellationToken.None);
        await harness.PromptService.RespondAsync(secondMeeting, MeetingStartPromptResponse.Record);

        Assert.Equal([firstMeeting, secondMeeting], harness.PromptService.PromptedMeetings);
        Assert.Equal(1, harness.Recorder.StartCount);
        Assert.Same(secondMetadata, harness.Recorder.StartMetadata.Single());
    }

    [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 CanceledCachedMeetingDoesNotPromptRecording()
    {
        var harness = CreateHarness(isRecording: false);
        var canceledMeeting = CreateMeeting(
            harness.Clock,
            id: "teams-canceled",
            subject: "Canceled project sync",
            isCanceled: true);
        harness.Provider.Meetings = [canceledMeeting];

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

        Assert.Empty(harness.PromptService.PromptedMeetings);
        Assert.Equal(0, harness.Recorder.StartCount);
    }

    [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,
        MeetingMetadata? metadata = null,
        bool isCanceled = false)
    {
        var start = clock.Now.Add(startOffset ?? TimeSpan.FromMinutes(30));
        return new CalendarMeeting(
            id,
            subject,
            start,
            start.Add(duration ?? TimeSpan.FromMinutes(30)),
            metadata,
            isCanceled);
    }

    private static SchedulerHarness CreateHarness(
        bool isRecording = false,
        bool enabled = true,
        bool autoAcceptPrompts = true)
    {
        var clock = new ManualCalendarPromptClock(new DateTimeOffset(2026, 6, 3, 9, 30, 0, TimeSpan.Zero));
        var provider = new RecordingCalendarMeetingProvider([]);
        var promptService = new CapturingMeetingStartPromptService(autoAcceptPrompts);
        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,
        CapturingMeetingStartPromptService 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 CapturingMeetingStartPromptService : IMeetingStartPromptService
    {
        private readonly bool autoAccept;
        private readonly List<PendingPrompt> pendingPrompts = [];

        public CapturingMeetingStartPromptService(bool autoAccept)
        {
            this.autoAccept = autoAccept;
        }

        public List<CalendarMeeting> PromptedMeetings { get; } = [];

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

        public Task RespondAsync(
            CalendarMeeting meeting,
            MeetingStartPromptResponse response)
        {
            var prompt = pendingPrompts.Single(pending => ReferenceEquals(pending.Meeting, meeting));
            return prompt.HandleResponseAsync(response, CancellationToken.None);
        }

        private sealed record PendingPrompt(
            CalendarMeeting Meeting,
            Func<MeetingStartPromptResponse, CancellationToken, Task> HandleResponseAsync);
    }

    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 int PromptStartCount { get; private set; }

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

        public List<MeetingMetadata?> StartMetadata { get; } = [];

        public Task<RecordingStatus> StartAsync(CancellationToken cancellationToken)
        {
            return StartRecordingAsync(null);
        }

        private Task<RecordingStatus> StartRecordingAsync(
            MeetingMetadata? metadata)
        {
            StartCount++;
            Commands.Add("start");
            StartMetadata.Add(metadata);
            CurrentStatus = Status(isRecording: true);
            return Task.FromResult(CurrentStatus);
        }

        public Task<RecordingStatus> StartFromPromptAsync(
            MeetingMetadata? metadata,
            CancellationToken cancellationToken)
        {
            PromptStartCount++;
            return StartRecordingAsync(metadata);
        }

        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; }
    }
}