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

namespace UltraCombos
{
    /// <summary>
    /// Read-only runtime monitor that renders selected component fields and properties
    /// into a single TextMeshProUGUI component using TMP rich-text colour tags.
    /// Drag the target TextMeshProUGUI into the Display Text field in the Inspector.
    /// </summary>
    [ExecuteAlways]
    public class DebugMonitorHUD : MonoBehaviour
    {
        // ── Data ──────────────────────────────────────────────────────────────────

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

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

        [Header("Display")]
        [SerializeField] private TextMeshProUGUI displayText;

        [Header("General")]
        [Tooltip("How many times per second the text is refreshed. 0 = every frame.")]
        [Range(0f, 60f)]
        public float refreshRate = 20f;

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

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

        private float nextRefreshTime;
        private readonly StringBuilder stringBuilder = new();

        // ── TMP colour tokens ─────────────────────────────────────────────────────

        private const string colHeader    = "#FFC940";
        private const string colLabel     = "#AAAAAA";
        private const string colFloat     = "#7EC8E3";
        private const string colInt       = "#7EC8E3";
        private const string colBoolTrue  = "#7EE37E";
        private const string colBoolFalse = "#E37E7E";
        private const string colString    = "#E3D47E";
        private const string colEnum      = "#C8A0E3";
        private const string colVec       = "#E3C87E";
        private const string colColor     = "#E3E3E3";
        private const string colReadonly  = "#666666";

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

        private void Update()
        {
            if (displayText == null)
            {
                return;
            }

            if (refreshRate > 0f && Time.unscaledTime < nextRefreshTime)
            {
                return;
            }

            nextRefreshTime = Time.unscaledTime + (refreshRate > 0f ? 1f / refreshRate : 0f);
            RebuildText();
        }

        // ── Text building ─────────────────────────────────────────────────────────

        private void RebuildText()
        {
            stringBuilder.Clear();

            var first = true;
            foreach (var entry in entries)
            {
                if (entry == null || entry.target == null || entry.fields.Count == 0)
                {
                    continue;
                }

                if (!first)
                {
                    stringBuilder.AppendLine();
                }
                first = false;

                AppendEntry(entry);
            }

            displayText.SetText(stringBuilder);
        }

        private void AppendEntry(Entry entry)
        {
            if (!string.IsNullOrEmpty(entry.groupLabel))
            {
                stringBuilder
                    .Append("<b><color=").Append(colHeader).Append('>')
                    .Append(entry.groupLabel)
                    .AppendLine("</color></b>");
            }

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

            foreach (var name in entry.fields)
            {
                // Resolve by name — check fields first, then properties.
                var mi = (MemberInfo)type.GetField(name, fieldFlags) ??
                         type.GetProperty(name, propFlags);
                if (mi == null)
                {
                    continue;
                }

                try
                {
                    AppendMember(entry.target, mi);
                }
                catch
                {
                    // Skip members that throw during reflection.
                }
            }
        }

        private void AppendMember(object obj, MemberInfo mi)
        {
            var label = NicifyName(mi.Name);
            var val = GetMemberValue(mi, obj);
            var ftype = GetMemberType(mi);

            stringBuilder
                .Append("<color=").Append(colLabel).Append('>')
                .Append(label)
                .Append("</color>  ");

            AppendValue(val, ftype);
            stringBuilder.AppendLine();
        }

        private void AppendValue(object val, Type ftype)
        {
            if (ftype == typeof(bool))
            {
                var b = (bool)val;
                stringBuilder
                    .Append("<color=").Append(b ? colBoolTrue : colBoolFalse).Append('>')
                    .Append(b ? "true" : "false")
                    .Append("</color>");
                return;
            }

            if (ftype == typeof(float))
            {
                stringBuilder
                    .Append("<color=").Append(colFloat).Append('>')
                    .Append(((float)val).ToString("G5", CultureInfo.InvariantCulture))
                    .Append("</color>");
                return;
            }

            if (ftype == typeof(int))
            {
                stringBuilder
                    .Append("<color=").Append(colInt).Append('>')
                    .Append(((int)val).ToString(CultureInfo.InvariantCulture))
                    .Append("</color>");
                return;
            }

            if (ftype == typeof(string))
            {
                stringBuilder
                    .Append("<color=").Append(colString).Append(">\"")
                    .Append(val as string ?? string.Empty)
                    .Append("\"</color>");
                return;
            }

            if (ftype == typeof(Vector2))
            {
                var v = (Vector2)val;
                stringBuilder
                    .Append("<color=").Append(colVec).Append(">(")
                    .Append(v.x.ToString("G4", CultureInfo.InvariantCulture)).Append(", ")
                    .Append(v.y.ToString("G4", CultureInfo.InvariantCulture))
                    .Append(")</color>");
                return;
            }

            if (ftype == typeof(Vector3))
            {
                var v = (Vector3)val;
                stringBuilder
                    .Append("<color=").Append(colVec).Append(">(")
                    .Append(v.x.ToString("G4", CultureInfo.InvariantCulture)).Append(", ")
                    .Append(v.y.ToString("G4", CultureInfo.InvariantCulture)).Append(", ")
                    .Append(v.z.ToString("G4", CultureInfo.InvariantCulture))
                    .Append(")</color>");
                return;
            }

            if (ftype == typeof(Color))
            {
                var c = (Color)val;
                var hex = ColorUtility.ToHtmlStringRGBA(c);
                // Coloured swatch character followed by the hex value.
                stringBuilder
                    .Append("<color=#").Append(hex).Append(">■</color>  ")
                    .Append("<color=").Append(colColor).Append(">#").Append(hex).Append("</color>");
                return;
            }

            if (ftype.IsEnum)
            {
                stringBuilder
                    .Append("<color=").Append(colEnum).Append('>')
                    .Append(val?.ToString() ?? "?")
                    .Append("</color>");
                return;
            }

            // Fallback: display the ToString() value as read-only italic text.
            stringBuilder
                .Append("<color=").Append(colReadonly).Append("><i>")
                .Append(val?.ToString() ?? "(null)")
                .Append("</i></color>");
        }

        // ── Reflection helpers ────────────────────────────────────────────────────

        private static Type GetMemberType(MemberInfo mi) =>
            mi is FieldInfo fi ? fi.FieldType : ((PropertyInfo)mi).PropertyType;

        private static object GetMemberValue(MemberInfo mi, object obj) =>
            mi is FieldInfo fi ? fi.GetValue(obj) : ((PropertyInfo)mi).GetValue(obj);

        /// <summary>Converts a camelCase or _prefixed field name to a readable label.</summary>
        private static string NicifyName(string s)
        {
            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();
        }
    }
}