Propose and negotiate supply hubs from the menus

src/main/java/net/tfminecraft/simplefactions/enums/SFGUI.java

@@ -78,6 +78,9 @@ public enum SFGUI {
 	INSTALLATION_DETAIL_VIEW,
 	SUPPLY_HUB_VIEW,
 	HOSTED_SUPPLY_HUB_VIEW,
+	HUB_PROPOSAL_LIST,
+	HUB_NEGOTIATION,
+	HUB_OFFER_LIST,
 	PLAYER_LEDGER_VIEW,
 	COMPANY_VIEW,
 	COMPANY_SLOTS_VIEW,

src/main/java/net/tfminecraft/simplefactions/guild/hub/HubAgreementMessenger.java

@@ -18,6 +18,7 @@ static void deliver(List<HubAgreementService.HubNotice> notices) {
             Player player = online(notice.playerName());
             if (player != null && notice.message() != null) {
                 player.sendMessage(notice.message());
+                net.tfminecraft.simplefactions.managers.inventory.HubProposalMenu.refresh(player);
             }
         }
     }

src/main/java/net/tfminecraft/simplefactions/guild/hub/HubAgreementService.java

@@ -133,6 +133,10 @@ public static boolean hasAgreement(Guild guild, String hostFactionId, String ins
         return findAgreement(guild, hostFactionId, installationId) != null;
     }
 
+    public static HubOffer offer(Guild guild, String hostFactionId, String installationId) {
+        return findOffer(guild, hostFactionId, installationId);
+    }
+
     public static HubAgreement findAgreement(Guild guild, String hostFactionId, String installationId) {
         if (guild == null || guild.getHubAgreements() == null) {
             return null;
@@ -251,6 +255,9 @@ static AgreementResult accept(
         if (offer == null) {
             return missingOrLapsed(guild, hostFactionId, installationId, facts, nowMillis);
         }
+        if (offer.lastActor() != null && offer.lastActor().equalsIgnoreCase(actorName)) {
+            return AgreementResult.fail("§cYou can only accept terms the other side sent");
+        }
         if (!actsFor(offer.awaiting(), guild, actorName, hostFactionId, facts)) {
             OfferSide sender = offer.awaiting() == OfferSide.HOST ? OfferSide.GUILD : OfferSide.HOST;
             if (actsFor(sender, guild, actorName, hostFactionId, facts)) {

src/main/java/net/tfminecraft/simplefactions/guild/hub/HubProposalCopy.java

@@ -0,0 +1,139 @@
+package net.tfminecraft.simplefactions.guild.hub;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import net.tfminecraft.simplefactions.guild.hub.HubEstimates.Destination;
+import net.tfminecraft.simplefactions.guild.hub.HubEstimates.Group;
+import net.tfminecraft.simplefactions.guild.hub.HubEstimates.Terms;
+import net.tfminecraft.simplefactions.utils.Formatter;
+
+/** Lore for the hub proposal list and the negotiation chest. Tax and fee are not recalculated here. */
+public final class HubProposalCopy {
+    private HubProposalCopy() {
+    }
+
+    public static int startingRate(int minPercent, int maxPercent) {
+        if (maxPercent < minPercent) {
+            return minPercent;
+        }
+        return (minPercent + maxPercent) / 2;
+    }
+
+    public static int clampRate(int rate, int minPercent, int maxPercent) {
+        return Math.max(minPercent, Math.min(maxPercent, rate));
+    }
+
+    public static long clampFeeCents(long cents, double maxFeeDenars) {
+        long maxCents = Math.round(Math.max(0, maxFeeDenars) * 100.0);
+        return Math.max(0, Math.min(maxCents, cents));
+    }
+
+    public static List<String> destinationLore(Destination destination) {
+        List<String> lore = new ArrayList<>();
+        if (destination == null) {
+            lore.add("§7Estimates are not ready yet");
+            return lore;
+        }
+        lore.add(destination.group() == Group.READY ? "§aReady now" : "§eWorth building");
+        lore.add("§7You: about " + signed(destination.operatorGain()) + "§7 a day");
+        lore.add("§7Host: about " + signed(destination.hostGain()) + "§7 a day");
+        if (destination.assumedRailway()) {
+            lore.add("§7No railway yet; assumes about "
+                    + Math.round(destination.assumedTrackBlocks()) + " blocks of track");
+        }
+        if (destination.group() == Group.WORTH_BUILDING || destination.installationId() == null) {
+            lore.add("§7A station has to be built here first");
+        } else if (destination.ownRealm()) {
+            lore.add("§eClick to build this hub");
+        } else {
+            lore.add("§eClick to negotiate");
+        }
+        return lore;
+    }
+
+    public static List<String> operatorLines(Destination destination, Terms terms) {
+        List<String> lore = new ArrayList<>();
+        if (destination == null || terms == null) {
+            lore.add("§7Estimates are not ready yet");
+            return lore;
+        }
+        if (destination.ownRealm()) {
+            lore.add("§7Your guild: about " + signed(destination.operatorGain()) + "§7 a day");
+            return lore;
+        }
+        lore.add("§7Your guild: about " + signed(destination.operatorGain()) + "§7 a day before tax");
+        lore.add("§7Tax §c-" + Formatter.formatMoney(terms.tax())
+                + "§7, fee §c-" + Formatter.formatMoney(terms.fee()));
+        lore.add("§7Net " + signed(terms.operatorNet()) + "§7 a day");
+        return lore;
+    }
+
+    public static List<String> hostLines(Destination destination, Terms terms, Map<String, String> guildNames) {
+        List<String> lore = new ArrayList<>();
+        if (destination == null || terms == null) {
+            lore.add("§7Estimates are not ready yet");
+            return lore;
+        }
+        if (destination.ownRealm()) {
+            lore.add("§7Your realm: about " + signed(destination.hostGain()) + "§7 a day");
+            return lore;
+        }
+        lore.add("§7Your guilds: about " + signed(destination.hostGain()) + "§7 a day");
+        lore.add("§7Hub tax §a+" + Formatter.formatMoney(terms.tax())
+                + "§7, fee §a+" + Formatter.formatMoney(terms.fee()));
+        lore.add("§7Net " + signed(terms.hostNet()) + "§7 a day");
+        if (destination.hostGuildGains() != null) {
+            for (Map.Entry<String, Double> entry : destination.hostGuildGains().entrySet()) {
+                if (entry.getKey() == null || entry.getValue() == null) {
+                    continue;
+                }
+                String name = guildNames == null ? null : guildNames.get(entry.getKey());
+                lore.add("§7" + (name == null || name.isBlank() ? entry.getKey() : name)
+                        + ": about " + signed(entry.getValue()));
+            }
+        }
+        return lore;
+    }
+
+    /**
+     * The rate at which the host's net is zero, given the fee already on the screen.
+     * The host gains before that rate when their other guilds already gain from the hub.
+     */
+    public static String breakEvenLine(Destination destination, long feeCents, int minPercent, int maxPercent) {
+        if (destination == null || destination.ownRealm()) {
+            return "§7A hub in your own realm has no tax or fee";
+        }
+        double fee = Math.max(0, feeCents) / 100.0;
+        double taxable = destination.taxableIncome();
+        if (taxable <= 0.0001) {
+            if (destination.hostGain() + fee >= 0) {
+                return "§7The host gains even at " + minPercent + "%";
+            }
+            return "§7The host does not break even inside " + minPercent + "-" + maxPercent + "%";
+        }
+        int shown = (int) Math.round((-destination.hostGain() - fee) * 100.0 / taxable);
+        if (shown < minPercent) {
+            return "§7The host gains even at " + minPercent + "%";
+        }
+        if (shown > maxPercent) {
+            return "§7The host does not break even inside " + minPercent + "-" + maxPercent + "%";
+        }
+        if (fee > 0) {
+            return "§7Break-even is about §e" + shown + "%§7 at this fee";
+        }
+        return "§7Break-even is about §e" + shown + "%";
+    }
+
+    static String signed(double amount) {
+        String money = Formatter.formatMoney(Math.abs(amount));
+        if (amount > 0.0001) {
+            return "§a+" + money;
+        }
+        if (amount < -0.0001) {
+            return "§c-" + money;
+        }
+        return "§e" + money;
+    }
+}