Plugin.cs

using BepInEx;
using BepInEx.Logging;
using BepInEx.Unity.IL2CPP;
using HarmonyLib;

namespace TunicTranslation;

[BepInPlugin(MyPluginInfo.PLUGIN_GUID, MyPluginInfo.PLUGIN_NAME, MyPluginInfo.PLUGIN_VERSION)]
[BepInProcess("Tunic.exe")]
public class Plugin : BasePlugin
{
	internal static new ManualLogSource Log;

	public override void Load()
	{
		Log = base.Log;
		Log.LogInfo($"Plugin {MyPluginInfo.PLUGIN_GUID} is loaded!");

		Harmony.CreateAndPatchAll(typeof(Plugin));

		Log.LogInfo($"Patches executed");
	}

	[HarmonyPrefix, HarmonyPatch(typeof(NPCDialogue), nameof(NPCDialogue.DisplayDialogue))]
	public static void NpcDialogueDisplayPreHook(LanguageLine script, bool pauseTime)
	{
		Log.LogInfo($"NPC dialogue: {script.text}");
	}

	[HarmonyPostfix, HarmonyPatch(typeof(Parser), nameof(Parser.findSymbol))]
	// ReSharper disable once InconsistentNaming, BepInEx expects double underscore
	public static void FindSymbolPostHook(string s, ref int __result)
	{
		// ignore special symbols (such as [sword]) and localizable strings (such as "npc_gen_moonlight")
		// localizable strings probably don't appear here, but it doesn't hurt to have the check
		if (s.StartsWith('[') || s.StartsWith('"'))
			return;

		// deny any multi-character symbols. Tunic will try to resolve sequences such as "oo" to a symbol, but we
		// currently we only support mapping 1 character to 1 symbol. If a symbol is not mapped (ie. return value is
		// -1), it will try individual characters which we force here.
		if (s.Length != 1)
		{
			__result = -1;
			return;
		}

		// map a character such as `A` or `$` to a symbol index and overwrite return value
		var resolved = ResolveChar(ReplacePhonetic(s[0]));
		if (resolved is { } r)
			__result = r;
		else
			Log.LogWarning($"Unable to resolve char: {s[0]}");
	}

	private const int AlphabetOffset = 42;
	/// <summary>
	/// The standard character part of the symbol set. This set is preceded by the original symbols and succeeded by
	/// various symbols.
	/// </summary>
	private const string Alphabet = " •,?!^()/\"\":0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ.";

	/// <summary> Replace special phonetic characters with the closest one in our alphabet </summary>
	private static char ReplacePhonetic(char c)
	{
		return c switch
		{
			'$' => 's', // sh, as in "$oud" (should), "wi$iz" (wishes)
			'%' => 't', // th, as in "%i^k" (think)
			'#' => 'd', // th, as in "$uh" (the)
			'^' => 'n', // ng, as in "surprIzi^" (surprising), "%l^" (thing)
			// NOTE: would want this to be a dash, but no such symbol exists
			'~' => '/', // small pause, used in uh~gehn (again), uh~gO (ago), uh~lahs (alas)
			_ => c
		};
	}

	/// <summary> Find a character in <see cref="Alphabet"/>, and return the symbol index if found. </summary>
	private static int? ResolveChar(char c)
	{
		var index = Alphabet.IndexOf(c);

		if (index == -1)
			index = Alphabet.ToLowerInvariant().IndexOf(c);

		if (index == -1)
			return null;

		return AlphabetOffset + index;
	}
}