using System;
using System.Text;
using System.Threading;
using ADOFAIRenderer.Core;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace ADOFAIRenderer.UI;

/// <summary>
/// On-screen overlay shown while a render is running: a statistics panel in the top-right corner and a level progress
/// bar near the bottom of the screen.
/// <para>
/// Created by <c>RenderManager.StartFFmpegThread</c> on a GameObject kept across scene loads, and reused for later
/// renders. The overlay is drawn on the game screen only; it is not part of the encoded video frames.
/// <see cref="Update"/> rebuilds the text every frame on the Unity main thread.
/// </para>
/// </summary>
internal class DebugMonitorUI : MonoBehaviour
{
    // --- Progress Bar UI Configuration Constants ---
    // Sizes and positions are canvas units at the 1920x1080 reference resolution of the CanvasScaler.

    /// <summary>Width of the progress bar; the fill width is <c>BarWidth * progress</c>.</summary>
    private const float BarWidth = 800f;
    /// <summary>Height of the progress bar.</summary>
    private const float BarHeight = 28f;
    /// <summary>Horizontal offset of the bar center from the screen center (0 = centered).</summary>
    private const float BarPosX = 0f;
    /// <summary>Vertical offset of the bar center from the screen center; -420 is 120 units above the bottom edge (540 - 420).</summary>
    private const float BarPosY = -420f; // Y position relative to screen center (Reference: 1920x1080)
    /// <summary>Font size of the percentage text drawn on the bar.</summary>
    private const int BarTextFontSize = 16; // Increased font size for visibility
    /// <summary>Unfilled bar color: opaque near-black with a slight blue tint.</summary>
    private static readonly Color BarBackgroundColor = new(0.08f, 0.08f, 0.1f, 1.0f);
    /// <summary>Filled part color: opaque cyan (#00CCFF).</summary>
    private static readonly Color BarFillColor = new(0.0f, 0.8f, 1.0f, 1.0f); // Sleek cyan/blue
    /// <summary>Percentage text color: opaque white.</summary>
    private static readonly Color BarTextColor = new(1.0f, 1.0f, 1.0f, 1.0f);

    // --- Progress Bar Outline Configuration Constants ---

    /// <summary>Color of the uGUI <see cref="Outline"/> drawn around the bar background.</summary>
    private static readonly Color BarOutlineColor = Color.white; // Contrasting white outline
    /// <summary>
    /// <c>Outline.effectDistance</c> of the bar outline: the background is redrawn shifted by +-3 units on both axes,
    /// which shows as a border about 3 units wide.
    /// </summary>
    private static readonly Vector2 BarOutlineDistance = new(3.0f, -3.0f); // Outline thickness

    /// <summary>Statistics text inside the top-right panel.</summary>
    private TextMeshProUGUI _text = null!;
    /// <summary>Progress bar background object (parent of the fill and the percentage text).</summary>
    private GameObject _progressBarObj = null!;
    /// <summary>Progress bar fill object.</summary>
    private GameObject _progressBarFillObj = null!;
    /// <summary>Fill rect, anchored to the left edge of the bar; its width is set every frame.</summary>
    private RectTransform _fillRect = null!;
    /// <summary>Text on the bar: percentage and "current floor / last floor index".</summary>
    private TextMeshProUGUI _progressText = null!;

    /// <summary>
    /// Builds the overlay canvas, the statistics panel and the progress bar. Layout values are canvas units at the
    /// 1920x1080 reference resolution.
    /// </summary>
    private void Start()
    {
        // Set UI layer (5, Unity's built-in "UI" layer)
        gameObject.layer = 5;

        // Canvas setup. Sorting order 9999 is below EscapeHandlerUI (10000) and the dialogs/windows of the mod.
        var canvas = gameObject.AddComponent<Canvas>();
        canvas.renderMode = RenderMode.ScreenSpaceOverlay;
        canvas.sortingOrder = 9999;

        // Dynamic resolution scaling against a 1920x1080 reference resolution; match 0.5 blends width and height
        var scaler = gameObject.AddComponent<CanvasScaler>();
        scaler.uiScaleMode = CanvasScaler.ScaleMode.ScaleWithScreenSize;
        scaler.referenceResolution = new Vector2(1920, 1080);
        scaler.screenMatchMode = CanvasScaler.ScreenMatchMode.MatchWidthOrHeight;
        scaler.matchWidthOrHeight = 0.5f;

        gameObject.AddComponent<GraphicRaycaster>();

        // Create background panel: 360x220 units, pivot and anchor at the top-right corner, inset 30 units from both edges
        var panelObj = new GameObject("BackgroundPanel");
        panelObj.transform.SetParent(transform, false);
        panelObj.layer = 5;
            
        var image = panelObj.AddComponent<Image>();
        image.color = new Color(0.08f, 0.08f, 0.1f, 0.88f); // Dark tone acrylic style

        var panelRect = panelObj.GetComponent<RectTransform>();
        panelRect.anchorMin = new Vector2(1, 1);
        panelRect.anchorMax = new Vector2(1, 1);
        panelRect.pivot = new Vector2(1, 1);
        panelRect.anchoredPosition = new Vector2(-30, -30);
        panelRect.sizeDelta = new Vector2(360, 220);

        // Create text: 16 pt rich text, top-left aligned, filling the panel minus a 20-unit margin
        var textObj = new GameObject("MonitorText");
        textObj.transform.SetParent(panelObj.transform, false);
        textObj.layer = 5;
            
        _text = textObj.AddComponent<TextMeshProUGUI>();
        _text.richText = true;
        _text.fontSize = 16;
        _text.alignment = TextAlignmentOptions.TopLeft;

        // Wrap long lines and let text that exceeds the panel height overflow instead of being truncated
        _text.textWrappingMode = TextWrappingModes.Normal;
        _text.overflowMode = TextOverflowModes.Overflow;

        // Apply the mod's bundled font (loaded by ModAssets.Load at mod initialization)
        _text.font = ModAssets.NanumSquareNeoNormal;

        var textRect = textObj.GetComponent<RectTransform>();
        textRect.anchorMin = Vector2.zero;
        textRect.anchorMax = Vector2.one;
        textRect.offsetMin = new Vector2(20, 20); // Padding margin
        textRect.offsetMax = new Vector2(-20, -20);

        // --- Progress Bar UI Setup ---
        // 1. Progress Bar Container: centered anchor/pivot, placed at (BarPosX, BarPosY) from the screen center
        _progressBarObj = new GameObject("ProgressBar");
        _progressBarObj.transform.SetParent(transform, false);
        _progressBarObj.layer = 5;

        var bgImage = _progressBarObj.AddComponent<Image>();
        bgImage.color = BarBackgroundColor;

        // Add progress bar outline component
        var bgOutline = _progressBarObj.AddComponent<Outline>();
        bgOutline.effectColor = BarOutlineColor;
        bgOutline.effectDistance = BarOutlineDistance;

        var barRect = _progressBarObj.GetComponent<RectTransform>();
        barRect.anchorMin = new Vector2(0.5f, 0.5f);
        barRect.anchorMax = new Vector2(0.5f, 0.5f);
        barRect.pivot = new Vector2(0.5f, 0.5f);
        barRect.anchoredPosition = new Vector2(BarPosX, BarPosY);
        barRect.sizeDelta = new Vector2(BarWidth, BarHeight);

        // 2. Progress Bar Fill: anchored to the left edge and stretched vertically (anchor x 0..0, y 0..1).
        //    sizeDelta.x is the fill width in units; Update sets it to BarWidth * progress.
        _progressBarFillObj = new GameObject("ProgressBarFill");
        _progressBarFillObj.transform.SetParent(_progressBarObj.transform, false);
        _progressBarFillObj.layer = 5;

        var fillImage = _progressBarFillObj.AddComponent<Image>();
        fillImage.color = BarFillColor;

        _fillRect = _progressBarFillObj.GetComponent<RectTransform>();
        _fillRect.anchorMin = new Vector2(0, 0);
        _fillRect.anchorMax = new Vector2(0, 1);
        _fillRect.pivot = new Vector2(0, 0.5f);
        _fillRect.anchoredPosition = Vector2.zero;
        _fillRect.sizeDelta = new Vector2(0, 0); // width will be updated dynamically in Update()

        // 3. Progress Bar Text: centered over the whole bar
        var progressTextObj = new GameObject("ProgressBarText");
        progressTextObj.transform.SetParent(_progressBarObj.transform, false);
        progressTextObj.layer = 5;

        _progressText = progressTextObj.AddComponent<TextMeshProUGUI>();
        _progressText.richText = true;
        _progressText.fontSize = BarTextFontSize;
        _progressText.alignment = TextAlignmentOptions.Center;
        _progressText.font = ModAssets.NanumSquareNeoNormal;
        _progressText.color = BarTextColor;

        // Black outline (90% opacity, 1.5-unit offset) keeps the white text readable over both the fill and the background
        var textOutline = progressTextObj.AddComponent<Outline>();
        textOutline.effectColor = new Color(0f, 0f, 0f, 0.9f);
        textOutline.effectDistance = new Vector2(1.5f, -1.5f);

        var textRectBar = progressTextObj.GetComponent<RectTransform>();
        textRectBar.anchorMin = Vector2.zero;
        textRectBar.anchorMax = Vector2.one;
        textRectBar.offsetMin = Vector2.zero;
        textRectBar.offsetMax = Vector2.zero;
    }

    /// <summary>
    /// Refreshes the statistics text and the progress bar from <see cref="RenderManager"/> and the game state.
    /// Values fall back to 0 (and the queue limit to <c>RenderManager.MaxQueuedFrames</c>) when no RenderManager exists.
    /// </summary>
    private void Update()
    {
        if (!_text) return;

        // Statistics lines:
        //   Queue            - frames waiting in ImageQueue for the render thread / queue frame limit
        //   Rendered Frames  - RenderManager.frameCount (frames produced by the game)
        //   Frames Sent      - RenderManager.framesSent (frames handed to the encoder; written by the render thread)
        //   Throttling       - RenderManager.throttleCount (times the main thread started waiting because ImageQueue
        //                      held more frames than its limit)
        //   Readback failures- RenderManager.readbackFailureCount (AsyncGPUReadback requests that completed with an error)
        //   Mono heap        - GC.GetTotalMemory(false), managed heap size in MiB without forcing a collection
        var sb = new StringBuilder();
        sb.AppendLine("<b><color=#00ccff>ADOFAI Renderer Realtime Monitor</color></b>");
        sb.AppendLine();
            
        var queueCount = 0;
        if (RenderManager.Instance)
        {
            // ImageQueue is shared with the render thread, so its count is read under the same lock
            lock (RenderManager.Instance.ImageQueue)
            {
                queueCount = RenderManager.Instance.ImageQueue.Count;
            }
        }
            
        sb.AppendLine($"• Queue: <b>{queueCount}</b> / {(RenderManager.Instance ? RenderManager.Instance.QueueFrameLimit : RenderManager.MaxQueuedFrames)} frames");
        sb.AppendLine($"• Rendered Frames: <b>{(RenderManager.Instance ? RenderManager.Instance.frameCount : 0)}</b>");
        sb.AppendLine($"• Frames Sent: <b>{(RenderManager.Instance ? Interlocked.Read(ref RenderManager.Instance.framesSent) : 0)}</b>");
            
        sb.AppendLine();
        sb.AppendLine($"• Throttling Controls: {(RenderManager.Instance ? RenderManager.Instance.throttleCount : 0)} times");
        sb.AppendLine($"• Readback Hard Failures: <color=#ff3333>{(RenderManager.Instance ? RenderManager.Instance.readbackFailureCount : 0)}</color> times");

        var memoryMb = GC.GetTotalMemory(false) / (1024.0 * 1024.0);
        sb.AppendLine($"• Mono Heap Memory: {memoryMb:F2} MB");

        _text.text = sb.ToString();

        // Update Progress Bar.
        // progress = seqID of the current floor / index of the last floor (listFloors.Count - 1), clamped to 0..1.
        // The text shows the percentage with one decimal and "(current / last)".
        var progress = 0f;
        var currentFloor = 0;
        var totalFloors = 0;

        if (scrController.instance && ADOBase.lm && ADOBase.lm.listFloors != null)
        {
            currentFloor = scrController.instance.currFloor ? scrController.instance.currFloor.seqID : 0;
            totalFloors = ADOBase.lm.listFloors.Count - 1;
            if (totalFloors > 0)
            {
                progress = Mathf.Clamp01((float)currentFloor / totalFloors);
            }
        }

        if (_fillRect) _fillRect.sizeDelta = new Vector2(BarWidth * progress, 0);
        if (_progressText) _progressText.text = $"{progress * 100f:F1}% ({currentFloor}/{totalFloors})";
    }
}