using UnityEditor;
using UnityEngine;

/// <summary>
/// Draws a <see cref="VideoClipPlaylist.Item"/> as two lines: the clip field and a
/// percent min-max slider (stored normalized 0..1) selecting the played portion.
/// </summary>
[CustomPropertyDrawer(typeof(VideoClipPlaylist.Item))]
public class VideoClipPlaylistItemDrawer : PropertyDrawer
{
    private const float PercentFieldWidth = 44f;
    private const float Gap = 4f;

    public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
        => EditorGUIUtility.singleLineHeight * 2f + EditorGUIUtility.standardVerticalSpacing;

    public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
    {
        SerializedProperty clipProp = property.FindPropertyRelative(nameof(VideoClipPlaylist.Item.clip));
        SerializedProperty rangeProp = property.FindPropertyRelative(nameof(VideoClipPlaylist.Item.range));

        EditorGUI.BeginProperty(position, label, property);

        float line = EditorGUIUtility.singleLineHeight;
        var clipRect = new Rect(position.x, position.y, position.width, line);
        EditorGUI.PropertyField(clipRect, clipProp, label);

        var rowRect = new Rect(position.x, clipRect.yMax + EditorGUIUtility.standardVerticalSpacing,
            position.width, line);
        Rect rangeRect = EditorGUI.PrefixLabel(rowRect, new GUIContent("Range (%)",
            "Played portion of the clip in percent (start/end)."));

        Vector2 range = rangeProp.vector2Value;
        float min = Mathf.Round(range.x * 1000f) / 10f;
        float max = Mathf.Round(range.y * 1000f) / 10f;

        var minRect = new Rect(rangeRect.x, rangeRect.y, PercentFieldWidth, line);
        var maxRect = new Rect(rangeRect.xMax - PercentFieldWidth, rangeRect.y, PercentFieldWidth, line);
        var sliderRect = new Rect(minRect.xMax + Gap, rangeRect.y,
            Mathf.Max(0f, rangeRect.width - 2f * (PercentFieldWidth + Gap)), line);

        EditorGUI.BeginChangeCheck();
        int indent = EditorGUI.indentLevel;
        EditorGUI.indentLevel = 0; // fields inside the row must not re-indent
        min = EditorGUI.FloatField(minRect, min);
        EditorGUI.MinMaxSlider(sliderRect, ref min, ref max, 0f, 100f);
        max = EditorGUI.FloatField(maxRect, max);
        EditorGUI.indentLevel = indent;
        if (EditorGUI.EndChangeCheck())
        {
            min = Mathf.Clamp(min, 0f, 100f);
            max = Mathf.Clamp(max, min, 100f);
            rangeProp.vector2Value = new Vector2(min / 100f, max / 100f);
        }

        EditorGUI.EndProperty();
    }
}