using System;
using System.Collections.Generic;
using System.Reflection;
using HarmonyLib;
using UnityEngine;

/// <summary>
/// Drops known-noise log lines inside Unity's own logger, so they never reach the
/// console or BepInEx's LogOutput.log. The game funnels both Debug.LogError and
/// Debug.LogWarning through Engine.Logger.Log(LogType, object) - that is the
/// single place where a message can be refused before anyone formats it.
/// </summary>
internal static class LogNoiseFilter
{
    private const string SelfTestProbe =
        "The character used for Underline is not available in font asset [radicade-filter-self-test].";

    internal static void Apply(Harmony harmony)
    {
        var prefix = AccessTools.Method(typeof(LogNoiseFilter), nameof(Prefix));
        if (prefix == null)
        {
            Diag.Warn("[LogFilter] the filter method was not found; known-noise log spam stays as-is.");
            return;
        }

        var patched = 0;
        foreach (var target in Targets())
        {
            try
            {
                harmony.Patch(target, prefix: new HarmonyMethod(prefix));
                patched++;
            }
            catch (Exception ex)
            {
                Diag.Warn("[LogFilter] could not patch " + target.DeclaringType?.Name + "." + target.Name +
                    " (" + ex.GetType().Name + ": " + ex.Message + ").");
            }
        }

        if (patched == 0)
        {
            Diag.Warn("[LogFilter] no Unity log funnel could be patched; the RigidbodyEx and font-underline spam stays as-is.");
            return;
        }

        Diag.Info("[LogFilter] armed on " + patched + " Unity log funnel(s): " + LogNoiseRules.PatternCount +
            " known-noise pattern(s) are dropped before they are printed.");
        SelfTest();
    }

    private static IEnumerable<MethodBase> Targets()
    {
        var log = AccessTools.Method(typeof(Logger), "Log",
            new[] { typeof(LogType), typeof(Il2CppSystem.Object) });
        if (log != null) yield return log;

        var logWithContext = AccessTools.Method(typeof(Logger), "Log",
            new[] { typeof(LogType), typeof(Il2CppSystem.Object), typeof(UnityEngine.Object) });
        if (logWithContext != null) yield return logWithContext;
    }

    private static bool Prefix(object[] __args)
    {
        try
        {
            if (__args == null || __args.Length < 2) return true;
            var message = __args[1];
            if (message == null) return true;
            return !LogNoiseRules.ShouldDrop(message.ToString());
        }
        catch
        {
            return true;
        }
    }

    /// <summary>
    /// Fires one probe line through Debug.LogWarning and checks that the rules saw
    /// it. If they did not, the filter is not wired to this build's logger and the
    /// log says so instead of pretending the spam is gone.
    /// </summary>
    private static void SelfTest()
    {
        try
        {
            var before = LogNoiseRules.DroppedCount;
            UnityEngine.Debug.LogWarning(SelfTestProbe);
            if (LogNoiseRules.DroppedCount > before)
                Diag.Info("[LogFilter] self-test PASS: a probe log line was intercepted inside Unity's logger.");
            else
                Diag.Warn("[LogFilter] self-test FAIL: a probe log line reached the log, so this build's spam is not being filtered.");
        }
        catch (Exception ex)
        {
            Diag.Warn("[LogFilter] self-test could not run (" + ex.GetType().Name + ": " + ex.Message + ").");
        }
    }
}