using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

namespace Amanotes
{
    /// <summary>
    /// Draws the "Local Packages" group in the Packages tab.
    /// Shows packages from the project's LocalPackages/ folder with enable/disable toggles.
    /// </summary>
    internal static class LocalPackagesTab
    {
        private static List<LocalPackagesManager.LocalPackageInfo> packages;
        private static bool needsRefresh = true;
        private static bool expanded = true;
        private static string localPackagesRoot;

        /// <summary>Called when a local package is enabled/disabled so the packages tab can refresh.</summary>
        internal static System.Action onPackageChanged;

        const float kPad = 4f;
        const float kToggleW = 40f;
        const float kVerW = 48f;
        const float kRowH = 24f;
        const float kInfoH = 16f;
        const float kRowGap = 6f;

        internal static void Refresh() => needsRefresh = true;

        internal static bool HasLocalPackages()
        {
            EnsureData();
            return packages != null && packages.Count > 0;
        }

        /// <summary>
        /// Returns the set of package names that are local packages,
        /// so DevModeTab can exclude them from its list.
        /// </summary>
        internal static HashSet<string> GetLocalPackageNames()
        {
            EnsureData();
            var set = new HashSet<string>();
            if (packages == null) return set;
            for (int i = 0; i < packages.Count; i++)
                set.Add(packages[i].packageName);
            return set;
        }

        private static void EnsureData()
        {
            if (!needsRefresh && packages != null) return;
            needsRefresh = false;
            packages = LocalPackagesManager.DetectLocalPackages();
            localPackagesRoot = LocalPackagesManager.FindLocalPackagesRoot();
        }

        internal static void OnGUI()
        {
            EnsureData();
            if (packages == null || packages.Count == 0) return;

            int enabledCount = 0;
            for (int i = 0; i < packages.Count; i++)
                if (packages[i].enabled) enabledCount++;

            expanded = EditorGUILayout.Foldout(expanded,
                $"Local Packages ({enabledCount}/{packages.Count})", true, sFoldout);

            if (!expanded) return;

            for (int i = 0; i < packages.Count; i++)
                DrawRow(packages[i]);

            // Separator after local packages section
            GUILayout.Space(4);
            var sep = GUILayoutUtility.GetRect(0, 2, GUILayout.ExpandWidth(true));
            EditorGUI.DrawRect(sep, new Color(0.25f, 0.5f, 0.25f, 0.5f));
            GUILayout.Space(4);
        }

        private static void DrawRow(LocalPackagesManager.LocalPackageInfo pkg)
        {
            float totalW = EditorGUIUtility.currentViewWidth;
            float nameW = totalW - kPad * 3 - kToggleW - kVerW - kPad;
            if (nameW < 40) nameW = 40;

            EditorGUILayout.BeginHorizontal(GUILayout.Height(kRowH));
            GUILayout.Space(kPad + 10); // indent under foldout

            // Package name
            var displayName = !string.IsNullOrEmpty(pkg.displayName) ? pkg.displayName : pkg.folderName;
            var nameRect = GUILayoutUtility.GetRect(nameW, kRowH, GUILayout.Width(nameW), GUILayout.Height(kRowH));
            if (Event.current.type == EventType.Repaint)
            {
                var style = pkg.enabled ? sName : sNameDisabled;
                style.Draw(nameRect, new GUIContent(displayName), false, false, false, false);
            }

            GUILayout.FlexibleSpace();

            // Version
            var verRect = GUILayoutUtility.GetRect(kVerW - 2, kRowH, GUILayout.Width(kVerW - 2), GUILayout.Height(kRowH));
            if (Event.current.type == EventType.Repaint)
                sDim.Draw(verRect, new GUIContent(pkg.version), false, false, false, false);

            // Enable/Disable toggle button
            var color = pkg.enabled ? new Color(0.4f, 0.9f, 0.4f, 1f) : new Color(0.9f, 0.4f, 0.4f, 0.7f);
            var label = pkg.enabled ? "ON" : "OFF";
            var oldBg = GUI.backgroundColor;
            GUI.backgroundColor = color;
            if (GUILayout.Button(label, sToggleBtn, GUILayout.Width(kToggleW), GUILayout.Height(kRowH - 2)))
            {
                if (pkg.enabled)
                {
                    if (EditorUtility.DisplayDialog("Disable Package",
                        $"Disable {pkg.displayName}?\n\nThis will rename package.json to .bak and remove it from manifest.json.",
                        "Disable", "Cancel"))
                    {
                        LocalPackagesManager.DisablePackage(pkg);
                        needsRefresh = true;
                        onPackageChanged?.Invoke();
                    }
                }
                else
                {
                    LocalPackagesManager.EnablePackage(pkg);
                    needsRefresh = true;
                    onPackageChanged?.Invoke();
                }
            }
            GUI.backgroundColor = oldBg;

            GUILayout.Space(kPad);
            EditorGUILayout.EndHorizontal();

            // Info line: folder path
            EditorGUILayout.BeginHorizontal(GUILayout.Height(kInfoH));
            GUILayout.Space(24);
            var pathDisplay = pkg.folderName;
            if (Event.current.type == EventType.Repaint)
            {
                float avail = totalW - 28;
                var pathRect = GUILayoutUtility.GetRect(avail, kInfoH, GUILayout.Height(kInfoH));
                sPath.Draw(pathRect, new GUIContent($"LocalPackages/{pathDisplay}"), false, false, false, false);
            }
            else
            {
                GUILayoutUtility.GetRect(totalW - 28, kInfoH, GUILayout.Height(kInfoH));
            }
            EditorGUILayout.EndHorizontal();

            GUILayout.Space(kRowGap);
            var sep = GUILayoutUtility.GetRect(0, 1, GUILayout.ExpandWidth(true));
            EditorGUI.DrawRect(sep, new Color(0.15f, 0.15f, 0.15f, 1f));
            GUILayout.Space(kRowGap);
        }

        // ── Styles ────────────────────────────────────────────────────────

        private static GUIStyle _sFoldout, _sName, _sNameDisabled, _sDim, _sPath, _sToggleBtn;

        private static GUIStyle sFoldout => _sFoldout ??= new GUIStyle(EditorStyles.foldout)
        {
            fontStyle = FontStyle.Bold
        };

        private static GUIStyle sName => _sName ??= new GUIStyle(EditorStyles.label)
        {
            clipping = TextClipping.Clip, wordWrap = false,
            normal = { textColor = Color.white },
            hover = { textColor = Color.white }
        };

        private static GUIStyle sNameDisabled => _sNameDisabled ??= new GUIStyle(EditorStyles.label)
        {
            clipping = TextClipping.Clip, wordWrap = false,
            normal = { textColor = new Color(0.5f, 0.5f, 0.5f) },
            hover = { textColor = new Color(0.5f, 0.5f, 0.5f) }
        };

        private static GUIStyle sDim => _sDim ??= new GUIStyle(EditorStyles.miniLabel)
        {
            alignment = TextAnchor.MiddleRight,
            normal = { textColor = new Color(0.5f, 0.5f, 0.5f) },
            hover = { textColor = new Color(0.5f, 0.5f, 0.5f) }
        };

        private static GUIStyle sPath => _sPath ??= new GUIStyle(EditorStyles.miniLabel)
        {
            wordWrap = false,
            normal = { textColor = new Color(0.5f, 0.5f, 0.5f) },
            hover = { textColor = new Color(0.5f, 0.5f, 0.5f) }
        };

        private static GUIStyle sToggleBtn
        {
            get
            {
                if (_sToggleBtn != null) return _sToggleBtn;
                _sToggleBtn = new GUIStyle(GUI.skin.button)
                {
                    fontStyle = FontStyle.Bold, fontSize = 10,
                    alignment = TextAnchor.MiddleCenter,
                    normal = { textColor = new Color(1f, 1f, 1f, 0.5f) },
                    hover = { textColor = new Color(1f, 1f, 1f, 0.5f) },
                    active = { textColor = new Color(1f, 1f, 1f, 0.5f) },
                    padding = new RectOffset(2, 2, 2, 2),
                    margin = new RectOffset(2, 0, 1, 1)
                };
                return _sToggleBtn;
            }
        }
    }
}