using ErsatzTV.Core.Domain;
using ErsatzTV.Core.Domain.Filler;
using ErsatzTV.Core.Domain.Scheduling;
using ErsatzTV.Core.Scheduling.YamlScheduling.Models;
using Newtonsoft.Json;

namespace ErsatzTV.Core.Scheduling.YamlScheduling;

public class YamlPlayoutContext(Playout playout, YamlPlayoutDefinition definition, int guideGroup)
{
    private static readonly JsonSerializerSettings JsonSettings = new()
    {
        NullValueHandling = NullValueHandling.Ignore
    };

    private readonly System.Collections.Generic.HashSet<int> _channelWatermarkIds = [];
    private readonly Stack<FillerKind> _fillerKind = new();
    private readonly Dictionary<int, string> _graphicsElements = [];

    private readonly System.Collections.Generic.HashSet<int> _visitedInstructions = [];
    private int _guideGroup = guideGroup;
    private bool _guideGroupLocked;
    private int _instructionIndex;
    private Option<MidRollSequence> _midRollSequence;
    private Option<string> _postRollSequence;
    private Option<string> _preRollSequence;

    public Playout Playout { get; } = playout;

    public List<PlayoutItem> AddedItems { get; } = [];

    public List<PlayoutHistory> AddedHistory { get; } = [];

    public YamlPlayoutDefinition Definition { get; } = definition;

    public DateTimeOffset CurrentTime { get; set; }

    public int InstructionIndex
    {
        get => _instructionIndex;
        set
        {
            _instructionIndex = value;
            _visitedInstructions.Add(value);
        }
    }

    public bool VisitedAll => _visitedInstructions.Count >= Definition.Playout.Count;

    public int PeekNextGuideGroup()
    {
        if (_guideGroupLocked)
        {
            return _guideGroup;
        }

        int result = _guideGroup + 1;
        if (result > 1000)
        {
            result = 1;
        }

        return result;
    }

    public void AdvanceGuideGroup()
    {
        if (_guideGroupLocked)
        {
            return;
        }

        _guideGroup++;
        if (_guideGroup > 1000)
        {
            _guideGroup = 1;
        }
    }

    public void LockGuideGroup(bool advance = true)
    {
        if (advance)
        {
            AdvanceGuideGroup();
        }

        _guideGroupLocked = true;
    }

    public void UnlockGuideGroup() => _guideGroupLocked = false;

    public void SetChannelWatermarkId(int id) => _channelWatermarkIds.Add(id);
    public void RemoveChannelWatermarkId(int id) => _channelWatermarkIds.Remove(id);
    public void ClearChannelWatermarkIds() => _channelWatermarkIds.Clear();
    public List<int> GetChannelWatermarkIds() => _channelWatermarkIds.ToList();

    public void SetGraphicsElement(int id, string variablesJson) => _graphicsElements.Add(id, variablesJson);
    public void RemoveGraphicsElement(int id) => _graphicsElements.Remove(id);
    public void ClearGraphicsElements() => _graphicsElements.Clear();
    public IReadOnlyDictionary<int, string> GetGraphicsElements() => _graphicsElements;

    public void SetPreRollSequence(string sequence) => _preRollSequence = sequence;
    public void ClearPreRollSequence() => _preRollSequence = Option<string>.None;
    public Option<string> GetPreRollSequence() => _preRollSequence;

    public void SetPostRollSequence(string sequence) => _postRollSequence = sequence;
    public void ClearPostRollSequence() => _postRollSequence = Option<string>.None;
    public Option<string> GetPostRollSequence() => _postRollSequence;

    public void SetMidRollSequence(MidRollSequence sequence) => _midRollSequence = sequence;
    public void ClearMidRollSequence() => _midRollSequence = Option<MidRollSequence>.None;
    public Option<MidRollSequence> GetMidRollSequence() => _midRollSequence;

    public void PushFillerKind(FillerKind fillerKind) => _fillerKind.Push(fillerKind);
    public void PopFillerKind() => _fillerKind.Pop();

    public Option<FillerKind> GetFillerKind() =>
        _fillerKind.TryPeek(out FillerKind fillerKind) ? fillerKind : Option<FillerKind>.None;

    public string Serialize()
    {
        string preRollSequence = null;
        foreach (string sequence in _preRollSequence)
        {
            preRollSequence = sequence;
        }

        var state = new State(
            _instructionIndex,
            _guideGroup,
            _guideGroupLocked,
            _channelWatermarkIds.ToList(),
            preRollSequence);

        return JsonConvert.SerializeObject(state, Formatting.None, JsonSettings);
    }

    public void Reset(PlayoutAnchor anchor, DateTimeOffset start)
    {
        CurrentTime = new DateTimeOffset(anchor.NextStart.ToLocalTime(), start.Offset);

        if (string.IsNullOrWhiteSpace(anchor.Context))
        {
            return;
        }

        State state = JsonConvert.DeserializeObject<State>(anchor.Context);
        if (state.ChannelWatermarkIds is null)
        {
            state = state with { ChannelWatermarkIds = [] };
        }

        foreach (int instructionIndex in Optional(state.InstructionIndex))
        {
            _instructionIndex = instructionIndex;
        }

        foreach (int guideGroup in Optional(state.GuideGroup))
        {
            _guideGroup = guideGroup;
        }

        foreach (bool guideGroupLocked in Optional(state.GuideGroupLocked))
        {
            _guideGroupLocked = guideGroupLocked;
        }

        foreach (int channelWatermarkId in state.ChannelWatermarkIds)
        {
            _channelWatermarkIds.Add(channelWatermarkId);
        }

        foreach (string preRollSequence in Optional(state.PreRollSequence))
        {
            _preRollSequence = preRollSequence;
        }
    }

    public record State(
        int? InstructionIndex,
        int? GuideGroup,
        bool? GuideGroupLocked,
        List<int> ChannelWatermarkIds,
        string PreRollSequence);

    public record MidRollSequence(string Sequence, string Expression);
}