using BepInEx;
using BepInEx.Logging;
using HarmonyLib;
using System;
using System.Collections.Generic;
using System.IO;
using UnityEngine;

namespace PartIDRedirection
{
    [BepInPlugin(PluginInfo.PLUGIN_GUID, PluginInfo.PLUGIN_NAME, PluginInfo.PLUGIN_VERSION)]
    public class PartIDRedirectionPlugin : BaseUnityPlugin
    {
        private const string REDIRECT_CONFIG_FILENAME = "PartID.redirects.cfg";

        internal static Dictionary<string, string> IdentifierMappings { get; private set; }
        internal static ManualLogSource PluginLogger { get; private set; }

        private void Awake()
        {
            PluginLogger = Logger;

            string configFilePath = Path.Combine(Paths.ConfigPath, REDIRECT_CONFIG_FILENAME);
            IdentifierMappings = LoadRedirectMappings(configFilePath);

            Logger.LogInfo($"Loaded {IdentifierMappings.Count} PartID redirect(s) from: {configFilePath}");

            try
            {
                Harmony harmony = new Harmony(PluginInfo.PLUGIN_GUID);
                harmony.PatchAll(typeof(PartsDatabasePatch));
                harmony.PatchAll(typeof(PartInstancePatch));
                Logger.LogInfo("Successfully patched PartsDatabase.GetDesc method");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to apply Harmony patches: {ex}");
            }
        }

        private static Dictionary<string, string> LoadRedirectMappings(string filePath)
        {
            var mappings = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);

            if (!File.Exists(filePath))
            {
                PluginLogger?.LogWarning($"Redirect configuration file not found: {filePath}");
                return mappings;
            }

            try
            {
                string[] lines = File.ReadAllLines(filePath);
                int lineNumber = 0;

                foreach (string rawLine in lines)
                {
                    lineNumber++;
                    string line = rawLine.Trim();

                    if (string.IsNullOrEmpty(line) || line.StartsWith("#"))
                        continue;

                    int separatorIndex = line.IndexOf('=');

                    if (separatorIndex <= 0 || separatorIndex >= line.Length - 1)
                    {
                        PluginLogger?.LogWarning($"Invalid format at line {lineNumber}: {line}");
                        continue;
                    }

                    string oldID = line.Substring(0, separatorIndex).Trim();
                    string newID = line.Substring(separatorIndex + 1).Trim();

                    if (string.IsNullOrEmpty(oldID) || string.IsNullOrEmpty(newID))
                    {
                        PluginLogger?.LogWarning($"Empty ID at line {lineNumber}: {line}");
                        continue;
                    }

                    if (mappings.ContainsKey(oldID))
                    {
                        PluginLogger?.LogWarning($"Duplicate mapping for '{oldID}' at line {lineNumber}. Using latest definition.");
                    }

                    mappings[oldID] = newID;
                }

                PluginLogger?.LogInfo($"Successfully parsed {mappings.Count} redirect mapping(s)");
            }
            catch (Exception ex)
            {
                PluginLogger?.LogError($"Error reading redirect file: {ex.Message}");
            }

            return mappings;
        }
    }

    internal static class PluginInfo
    {
        public const string PLUGIN_GUID = "com.anonymus637.partidredirection";
        public const string PLUGIN_NAME = "PartID Redirection";
        public const string PLUGIN_VERSION = "1.0.0";
    }

    [HarmonyPatch(typeof(PartsDatabase))]
    internal static class PartsDatabasePatch
    {
        [HarmonyPatch("GetDesc", new Type[] { typeof(string), typeof(GetString) })]
        [HarmonyPrefix]
        private static void GetDescPrefix(ref string partName)
        {
            RedirectPartName(ref partName);
        }

        [HarmonyPatch("GetPartDescription")]
        [HarmonyPrefix]
        private static void GetPartDescriptionPrefix(ref string partName)
        {
            RedirectPartName(ref partName);
        }

        private static void RedirectPartName(ref string partName)
        {
            if (string.IsNullOrEmpty(partName))
                return;

            string cleanPartName = partName;
            int newlineIndex = partName.IndexOfAny(new char[] { '\n', '\r' });
            if (newlineIndex > 0)
            {
                cleanPartName = partName.Substring(0, newlineIndex).Trim();
            }

            if (PartIDRedirectionPlugin.IdentifierMappings.TryGetValue(cleanPartName, out string redirectedIdentifier))
            {
                PartIDRedirectionPlugin.PluginLogger?.LogInfo(
                    $"Redirecting part identifier: '{cleanPartName}' → '{redirectedIdentifier}'"
                );

                if (newlineIndex > 0)
                {
                    partName = redirectedIdentifier + partName.Substring(newlineIndex);
                }
                else
                {
                    partName = redirectedIdentifier;
                }
            }
        }
    }

    [HarmonyPatch(typeof(PartInstance))]
    internal static class PartInstancePatch
    {
        [HarmonyPatch("name", MethodType.Getter)]
        [HarmonyPostfix]
        private static void NameGetterPostfix(PartInstance __instance, ref string __result)
        {
            if (string.IsNullOrEmpty(__result))
                return;

            string cleanPartName = __result;
            int newlineIndex = __result.IndexOfAny(new char[] { '\n', '\r' });
            if (newlineIndex > 0)
            {
                cleanPartName = __result.Substring(0, newlineIndex).Trim();
            }

            if (PartIDRedirectionPlugin.IdentifierMappings.TryGetValue(cleanPartName, out string redirectedIdentifier))
            {
                if (newlineIndex > 0)
                {
                    __result = redirectedIdentifier + __result.Substring(newlineIndex);
                }
                else
                {
                    __result = redirectedIdentifier;
                }
            }
        }
    }
}