rjw-genes/Source/Genes/Special/Patches/Patch_PregnancyOverwrite.cs

using HarmonyLib;
using RimWorld;
using rjw;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Verse;
using static HarmonyLib.Code;

namespace RJW_Genes
{
    [HarmonyPatch(typeof(SexUtility), "Aftersex")]
    public class Patch_PregnancyOverwrite
    {
        public const int FACTION_GOODWILL_CHANGE = -5;

        public static void Postfix(SexProps props)
        {
            if (props == null || props.pawn == null || props.partner == null || props.partner.IsAnimal())
            {
                return;
            }

            Pawn pawn = props.pawn;
            Pawn partner = props.partner;

            if (pawn.genes == null || partner.genes == null) return;

            // If both have the swap gene, nothing happens
            if (GeneUtility.HasGeneNullCheck(pawn, GeneDefOf.rjw_genes_pregnancy_overwrite)
                && GeneUtility.HasGeneNullCheck(partner, GeneDefOf.rjw_genes_pregnancy_overwrite))
                return;

            // If both are pregnant, we have some weird interaction. Exit Early 
            if (pawn.IsPregnant() && partner.IsPregnant())
                return;
            // If neither are pregnant, nothing can happen.
            if (!pawn.IsPregnant() && !partner.IsPregnant())
                return;

            ModLog.Debug("Firing Pregnancy Overwrite Patch - Passed Simple NullChecks");

            if (pawn.IsPregnant() 
                && GeneUtility.HasGeneNullCheck(partner, GeneDefOf.rjw_genes_pregnancy_overwrite))
                    TryReplacePregnancy(partner, pawn);

            if (partner.IsPregnant() 
                && GeneUtility.HasGeneNullCheck(pawn, GeneDefOf.rjw_genes_pregnancy_overwrite))
                TryReplacePregnancy(pawn, partner);
        }

        /// <summary>
        /// Tries to replace an existing pregnancy with a new pregnancy at the same gestation process. 
        /// The new pregnancy will have the same mother, but a new father and a new set of genes. 
        /// 
        /// There is a check for pregnancy that checks for the general fertility (using Vanilla Functions) and multiplies it with a xml-configurable chance.
        /// If anything is replaced, there will be a faction penalty applied. 
        /// </summary>
        /// <param name="replacer"></param>
        /// <param name="pregnant"></param>
        public static void TryReplacePregnancy(Pawn replacer, Pawn pregnant)
        {
            
            ModLog.Debug($"Firing Pregnancy Overwrite for {replacer} and {pregnant}");

            Hediff pregnancyHediff = PregnancyUtility.GetPregnancyHediff(pregnant);
            if (pregnancyHediff == null)
                return;

            if (DiseaseHelper.IsImmuneAgainstGeneticDisease(pregnant, GeneDefOf.rjw_genes_pregnancy_overwrite))
            {
                ModLog.Debug($"{pregnant} is immune against rjw_genes_pregnancy_overwrite from {replacer}");
                return;
            }

            ChanceExtension chanceExt = GeneDefOf.rjw_genes_pregnancy_overwrite.GetModExtension<ChanceExtension>();
            float chance = chanceExt != null ? chanceExt.chance : 0.25f;
            chance *= PregnancyUtility.PregnancyChanceForPartners(pregnant, replacer);

            if ((new Random()).Next() < chance)
            {
                float gestationProgress = pregnancyHediff.Severity;

                PregnancyUtility.ForceEndPregnancy(pregnant);

                PregnancyHelper.StartVanillaPregnancy(pregnant, replacer);
                Hediff replacementPregnancyHediff = PregnancyUtility.GetPregnancyHediff(pregnant);
                replacementPregnancyHediff.Severity = gestationProgress;

                FactionUtility.HandleFactionGoodWillPenalties(replacer, pregnant, "rjw_genes_GoodwillChangedReason_OverwritePregnancy", FACTION_GOODWILL_CHANGE);
            } else
            {
                ModLog.Debug($"Did not Pregnancy-Overwrite for {replacer} and {pregnant}. Failed: roll<({chanceExt.chance} x {PregnancyUtility.PregnancyChanceForPartners(pregnant,replacer)}[PregnancyChance for Pawns])");
            }
        }

    }
}