using System;
using UnityEngine;

namespace IdleSpectator;

/// <summary>
/// Owns hover preview and camera read-pause lease for the life-saga rail.
/// AFK chrome is always character beat caption (Identity + Beat + Context);
/// the saga panel is hover depth only (no Dossier/Saga tabs).
/// </summary>
public static class LifeSagaViewController
{
    public const string ReadPauseOwner = "saga_hover";
    /// <summary>Only used if an exit was deferred; glyph leave finishes immediately.</summary>
    public const float HoverExitGraceSeconds = 0.05f;

    /// <summary>
    /// Compatibility enum for harness asserts. AFK chrome never pins Saga;
    /// <see cref="EffectiveTab"/> is Saga only while a hover preview is active.
    /// </summary>
    public enum Tab
    {
        Dossier = 0,
        Saga = 1
    }

    private static long _hoverPreviewId;
    private static float _hoverExitAt = -1f;
    private static bool _pauseHeld;

    public static Tab SelectedTab => Tab.Dossier;
    public static long PersistentSagaId => 0;
    public static long HoverPreviewId => _hoverPreviewId;
    public static bool IsHoverPreview => _hoverPreviewId != 0;

    /// <summary>Saga while hovering a rail glyph; otherwise Dossier (caption body).</summary>
    public static Tab EffectiveTab =>
        _hoverPreviewId != 0 ? Tab.Saga : Tab.Dossier;

    public static long EffectiveSagaId => _hoverPreviewId;

    /// <summary>
    /// Harness/compat: Dossier cancels hover. Saga begins hover preview of the watched MC
    /// when on the roster (no persistent pin / empty pick chrome).
    /// </summary>
    public static void SelectTab(Tab tab)
    {
        if (tab == Tab.Dossier)
        {
            CancelPreviewAndPause();
            WatchCaption.RequestRelayout();
            return;
        }

        long watch = WatchedMcId();
        if (watch != 0)
        {
            BeginHoverPreview(watch);
            return;
        }

        CancelPreviewAndPause();
        WatchCaption.RequestRelayout();
    }

    /// <summary>No-op: Prefer click no longer pins a persistent Saga subject.</summary>
    public static void SetPersistentSaga(long unitId)
    {
        _ = unitId;
    }

    /// <summary>No-op: Lore return no longer restores a Saga tab.</summary>
    public static void StashLoreReturn(long unitId)
    {
        _ = unitId;
    }

    /// <summary>No-op: Lore close leaves caption chrome as-is.</summary>
    public static bool TryRestoreAfterLore()
    {
        return false;
    }

    public static void BeginHoverPreview(long unitId)
    {
        if (unitId == 0)
        {
            return;
        }

        if (_hoverPreviewId == 0)
        {
            // Capture the already-painted dossier typography before hover changes ownership
            // of the header. Every glyph in this hover session uses that same ceiling.
            WatchCaption.BeginSagaHoverSession();
        }

        _hoverExitAt = -1f;
        _hoverPreviewId = unitId;
        WatchCaption.PrimeSagaHoverHeader(unitId);
        if (!_pauseHeld)
        {
            InterestDirector.AcquireReadPause(ReadPauseOwner);
            _pauseHeld = true;
        }

        WatchCaption.RequestRelayout();
    }

    public static void EndHoverPreview()
    {
        if (_hoverPreviewId == 0 && !_pauseHeld)
        {
            return;
        }

        // Relayout / glyph→glyph can fire Exit while the pointer is still on a glyph.
        // Keep the preview in that case; otherwise restore caption body immediately.
        if (LifeSagaRail.IsPointerOverGlyph())
        {
            _hoverExitAt = -1f;
            return;
        }

        // PointerExit is delivered before PointerEnter when scrubbing directly from one
        // glyph to another. Keep Saga ownership alive across that event handoff so the
        // dossier cannot paint one intermediate header frame.
        _hoverExitAt = Time.unscaledTime + HoverExitGraceSeconds;
    }

    public static void Tick()
    {
        if (_hoverPreviewId == 0)
        {
            return;
        }

        // Actively hovering (no exit armed) - keep preview until EndHoverPreview.
        if (_hoverExitAt < 0f)
        {
            return;
        }

        // Deferred exit was armed; cancel it if the pointer landed on another glyph.
        if (LifeSagaRail.IsPointerOverGlyph())
        {
            _hoverExitAt = -1f;
            return;
        }

        if (Time.unscaledTime < _hoverExitAt)
        {
            return;
        }

        FinishHoverExit();
    }

    public static void CancelPreviewAndPause()
    {
        bool hadPreview = _hoverPreviewId != 0;
        _hoverExitAt = -1f;
        _hoverPreviewId = 0;
        if (hadPreview)
        {
            WatchCaption.EndSagaHoverSession();
        }

        if (_pauseHeld)
        {
            InterestDirector.ReleaseReadPause(ReadPauseOwner);
            _pauseHeld = false;
        }
    }

    public static void Clear()
    {
        CancelPreviewAndPause();
    }

    /// <summary>
    /// Harness: force-complete hover exit as if the pointer left every glyph.
    /// </summary>
    public static void HarnessTickExitAwayFromChrome()
    {
        if (_hoverPreviewId == 0 && !_pauseHeld)
        {
            return;
        }

        FinishHoverExit();
    }

    public static LifeSagaViewModel BuildEffectivePresentation()
    {
        long id = EffectiveSagaId;
        return id != 0 ? LifeSagaPresentation.Build(id) : new LifeSagaViewModel();
    }

    private static void FinishHoverExit()
    {
        _hoverExitAt = -1f;
        _hoverPreviewId = 0;
        WatchCaption.EndSagaHoverSession();
        if (_pauseHeld)
        {
            InterestDirector.ReleaseReadPause(ReadPauseOwner);
            _pauseHeld = false;
        }

        WatchCaption.RequestRelayout();
    }

    private static long WatchedMcId()
    {
        long watchId = EventFeedUtil.SafeId(
            MoveCamera.hasFocusUnit() ? MoveCamera._focus_unit : null);
        return watchId != 0 && LifeSagaRoster.IsMc(watchId) ? watchId : 0;
    }
}