using System;
using System.Collections.Generic;
using System.Globalization;
using System.Reflection;
using System.Text;
using UnityEngine;

namespace UltraCombos
{
    /// <summary>
    /// Runtime settings panel. Press the configured toggle key (default F1) to show or hide.
    /// Drag any Component into the Entries list via the Inspector, select the fields to expose,
    /// and the panel lets you tweak them live at runtime.
    /// </summary>
    public class DebugSettingsGUI : MonoBehaviour
    {
        // ── Data ──────────────────────────────────────────────────────────────────

        [Serializable]
        public class Entry
        {
            public UnityEngine.Object target;
            public string groupLabel = string.Empty;

            /// <summary>Field names written by the custom Editor.</summary>
            public List<string> fields = new();
        }

        [Header("General")]
        public KeyCode toggleKey = KeyCode.F1;
        public Rect initialRect = new Rect(10, 10, 360, 520);

        [Header("Entries")]
        public List<Entry> entries = new();

        // ── Runtime state ─────────────────────────────────────────────────────────

        private bool isVisible;
        private Rect windowRect;
        private Vector2 scrollPos;

        // Styles — lazy-initialised inside OnGUI so GUI.skin is available.
        private bool stylesInitialized;
        private GUIStyle headerStyle;
        private GUIStyle subBoxStyle;
        private GUIStyle labelStyle;
        private GUIStyle readonlyStyle;

        // ── Unity callbacks ───────────────────────────────────────────────────────

        private void Awake()
        {
            windowRect = initialRect;
        }

        private void Update()
        {
            if (Input.GetKeyDown(toggleKey))
            {
                isVisible = !isVisible;
            }
        }

        private void OnGUI()
        {
            if (!isVisible)
            {
                return;
            }

            EnsureStyles();
            windowRect = GUILayout.Window(
                GetInstanceID(), windowRect, DrawWindow,
                $"  Debug Settings      [{toggleKey}: toggle]");
        }

        // ── Window ────────────────────────────────────────────────────────────────

        private void DrawWindow(int id)
        {
            scrollPos = GUILayout.BeginScrollView(scrollPos);

            var first = true;
            foreach (var e in entries)
            {
                if (e == null || e.target == null || e.fields.Count == 0)
                {
                    continue;
                }
                if (!first)
                {
                    GUILayout.Space(6);
                }
                first = false;
                DrawEntry(e);
            }

            GUILayout.EndScrollView();
            GUI.DragWindow(new Rect(0, 0, 10000, 22));
        }

        private void DrawEntry(Entry entry)
        {
            if (!string.IsNullOrEmpty(entry.groupLabel))
            {
                GUILayout.Label(entry.groupLabel, headerStyle);
            }

            var type = entry.target.GetType();
            const BindingFlags flags =
                BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;

            foreach (var name in entry.fields)
            {
                var fi = type.GetField(name, flags);
                if (fi == null)
                {
                    continue;
                }
                try
                {
                    DrawField(entry.target, fi);
                }
                catch
                {
                    // Skip fields that throw during reflection.
                }
            }
        }

        // ── Per-type drawing ──────────────────────────────────────────────────────

        private void DrawField(object obj, FieldInfo fi)
        {
            var val = fi.GetValue(obj);
            var ftype = fi.FieldType;
            var label = NicifyName(fi.Name);

            if (ftype == typeof(bool))
            {
                DrawBool(obj, fi, (bool)val, label);
            }
            else if (ftype == typeof(float))
            {
                DrawFloat(obj, fi, (float)val, label);
            }
            else if (ftype == typeof(int))
            {
                DrawInt(obj, fi, (int)val, label);
            }
            else if (ftype == typeof(string))
            {
                DrawString(obj, fi, (string)val, label);
            }
            else if (ftype == typeof(Vector2))
            {
                DrawVector2(obj, fi, (Vector2)val, label);
            }
            else if (ftype == typeof(Vector3))
            {
                DrawVector3(obj, fi, (Vector3)val, label);
            }
            else if (ftype == typeof(Color))
            {
                DrawColor(obj, fi, (Color)val, label);
            }
            else if (ftype.IsEnum)
            {
                DrawEnum(obj, fi, val, ftype, label);
            }
            else
            {
                // Unsupported type — read-only display.
                using (new GUILayout.HorizontalScope())
                {
                    GUILayout.Label(label, labelStyle, GUILayout.Width(150));
                    GUILayout.Label(val?.ToString() ?? "(null)", readonlyStyle);
                }
            }
        }

        private void DrawBool(object obj, FieldInfo fi, bool val, string label)
        {
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));
                var next = GUILayout.Toggle(val, val ? "✓" : string.Empty);
                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawFloat(object obj, FieldInfo fi, float val, string label)
        {
            var range = fi.GetCustomAttribute<RangeAttribute>();
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));

                float next;
                if (range != null)
                {
                    next = GUILayout.HorizontalSlider(val, range.min, range.max);
                    GUILayout.Label(next.ToString("F2"), GUILayout.Width(44));
                }
                else
                {
                    var s = GUILayout.TextField(val.ToString("G5"));
                    next = float.TryParse(s, out var p) ? p : val;
                }

                if (!Mathf.Approximately(next, val))
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawInt(object obj, FieldInfo fi, int val, string label)
        {
            var range = fi.GetCustomAttribute<RangeAttribute>();
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));

                int next;
                if (range != null)
                {
                    next = Mathf.RoundToInt(GUILayout.HorizontalSlider(val, range.min, range.max));
                    GUILayout.Label(next.ToString(), GUILayout.Width(32));
                }
                else
                {
                    var s = GUILayout.TextField(val.ToString());
                    next = int.TryParse(s, out var p) ? p : val;
                }

                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawString(object obj, FieldInfo fi, string val, string label)
        {
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));
                var next = GUILayout.TextField(val ?? string.Empty);
                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawVector2(object obj, FieldInfo fi, Vector2 val, string label)
        {
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));
                GUILayout.Label("X", GUILayout.Width(14));
                var x = ParseFloat(GUILayout.TextField(val.x.ToString("G4"), GUILayout.Width(52)), val.x);
                GUILayout.Label("Y", GUILayout.Width(14));
                var y = ParseFloat(GUILayout.TextField(val.y.ToString("G4"), GUILayout.Width(52)), val.y);
                var next = new Vector2(x, y);
                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawVector3(object obj, FieldInfo fi, Vector3 val, string label)
        {
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));
                GUILayout.Label("X", GUILayout.Width(14));
                var x = ParseFloat(GUILayout.TextField(val.x.ToString("G4"), GUILayout.Width(40)), val.x);
                GUILayout.Label("Y", GUILayout.Width(14));
                var y = ParseFloat(GUILayout.TextField(val.y.ToString("G4"), GUILayout.Width(40)), val.y);
                GUILayout.Label("Z", GUILayout.Width(14));
                var z = ParseFloat(GUILayout.TextField(val.z.ToString("G4"), GUILayout.Width(40)), val.z);
                var next = new Vector3(x, y, z);
                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private void DrawColor(object obj, FieldInfo fi, Color val, string label)
        {
            GUILayout.Label(label, headerStyle);
            using (new GUILayout.VerticalScope(subBoxStyle))
            {
                var r = SliderChannel("R", val.r);
                var g = SliderChannel("G", val.g);
                var b = SliderChannel("B", val.b);
                var a = SliderChannel("A", val.a);
                var next = new Color(r, g, b, a);
                if (next != val)
                {
                    fi.SetValue(obj, next);
                }
            }
        }

        private float SliderChannel(string ch, float val)
        {
            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(ch, GUILayout.Width(16));
                var next = GUILayout.HorizontalSlider(val, 0f, 1f);
                GUILayout.Label(next.ToString("F2"), GUILayout.Width(36));
                return next;
            }
        }

        private void DrawEnum(object obj, FieldInfo fi, object val, Type type, string label)
        {
            var names = Enum.GetNames(type);
            var values = Enum.GetValues(type);
            var cur = Array.IndexOf(values, val);

            using (new GUILayout.HorizontalScope())
            {
                GUILayout.Label(label, labelStyle, GUILayout.Width(150));

                if (names.Length <= 4)
                {
                    var next = GUILayout.SelectionGrid(cur, names, names.Length);
                    if (next != cur)
                    {
                        fi.SetValue(obj, values.GetValue(next));
                    }
                }
                else
                {
                    // Cycle through with prev / next buttons for long enums.
                    if (GUILayout.Button("◀", GUILayout.Width(24)))
                    {
                        cur = (cur - 1 + names.Length) % names.Length;
                    }
                    GUILayout.Label(names[Mathf.Clamp(cur, 0, names.Length - 1)]);
                    if (GUILayout.Button("▶", GUILayout.Width(24)))
                    {
                        cur = (cur + 1) % names.Length;
                    }
                    fi.SetValue(obj, values.GetValue(Mathf.Clamp(cur, 0, values.Length - 1)));
                }
            }
        }

        // ── Helpers ───────────────────────────────────────────────────────────────

        private static float ParseFloat(string s, float fallback)
            => float.TryParse(s, NumberStyles.Float, CultureInfo.InvariantCulture, out var v) ? v : fallback;

        /// <summary>Converts a camelCase or _prefixed field name to a readable label.</summary>
        private static string NicifyName(string s)
        {
            // Strip leading underscores and "m_" prefix.
            var start = 0;
            while (start < s.Length && s[start] == '_')
            {
                start++;
            }
            if (s.Length > start + 1 && s[start] == 'm' && s[start + 1] == '_')
            {
                start += 2;
            }

            var sb = new StringBuilder();
            for (var i = start; i < s.Length; i++)
            {
                var c = s[i];
                if (i == start)
                {
                    sb.Append(char.ToUpper(c));
                    continue;
                }
                if (char.IsUpper(c) && !char.IsUpper(s[i - 1]))
                {
                    sb.Append(' ');
                }
                sb.Append(c);
            }
            return sb.ToString();
        }

        // ── Styles — OnGUI-safe lazy initialisation ────────────────────────────────

        private void EnsureStyles()
        {
            if (stylesInitialized)
            {
                return;
            }
            stylesInitialized = true;

            headerStyle = new GUIStyle(GUI.skin.label)
            {
                fontStyle = FontStyle.Bold,
                normal = { textColor = new Color(1f, 0.85f, 0.3f) }
            };

            subBoxStyle = new GUIStyle(GUI.skin.box)
            {
                padding = new RectOffset(6, 6, 3, 3),
                margin = new RectOffset(2, 2, 0, 0)
            };

            labelStyle = new GUIStyle(GUI.skin.label)
            {
                normal = { textColor = new Color(0.85f, 0.85f, 0.85f) }
            };

            readonlyStyle = new GUIStyle(GUI.skin.label)
            {
                normal = { textColor = new Color(0.55f, 0.55f, 0.55f) },
                fontStyle = FontStyle.Italic
            };
        }
    }
}