angelTomo9 · Oct 12, 2026
diff --git a/api/src/lib/ancientRunicLeatherHorseShinGuardBench.ts b/api/src/lib/ancientRunicLeatherHorseShinGuardBench.ts
@@ -0,0 +1,228 @@
+import crypto from "node:crypto";
+
+/**
+ * Ancient Runic Leather Horse Shin Guard Bench, Mithril Cannon Bone Splint Rig & Celestial Valkyrie Cannon Armor Sanctum Engine for OpenAO MMORPG.
+ * Simulates equestrian shin guard and cannon bone protector crafting benches (Elder Shin Guard Bench, Runic Oak Shin Guard Rig, Celestial Void Valkyrie Shin Guard Sanctum),
+ * raw tanned bull cannon straps, tempered mithril cannon bone splints and astral metacarpal pads,
+ * novice expedition shin guards and sovereign valkyrie shin guard recipes,
+ * independent steed cannon bone impact deflection ratings and flexor tendon shielding ratings,
+ * calibrated clamped shin guard stability bonuses,
+ * upfront leather material deduction on all craft attempts, consistent remainingProvidedLeathers return shapes across all paths,
+ * immutable bench cloning for safe rollbacks on both craft and maintain operations, cached static catalog maxima,
+ * crypto-secure default gameplay rolls strictly in [0, 1), and horse shin guard bench maintenance routines.
+ */
+
+export type ShinGuardBenchType = "ELDER_SHIN_GUARD_BENCH" | "RUNIC_OAK_SHIN_GUARD_RIG" | "CELESTIAL_VOID_VALKYRIE_SHIN_GUARD_SANCTUM";
+export type RawLeatherShinGuardType = "TANNED_BULL_CANNON_STRAP" | "TEMPERED_MITHRIL_CANNON_SPLINT" | "CELESTIAL_VOID_ASTRAL_METACARPAL_PAD";
+export type ShinGuardRecipeType = "NOVICE_EXPEDITION_SHIN_GUARD" | "WARMASTER_MITHRIL_REINFORCED_SHIN_GUARD" | "CELESTIAL_VOID_VALKYRIE_SOVEREIGN_SHIN_GUARD";
+
+export interface ShinGuardBenchData {
+    benchType: ShinGuardBenchType;
+    maxDurability: number;
+    leathercraftPower: number;
+    baseSuccessRatePercent: number; // 0 to 100
+    shinGuardStabilityBonusPercent: number;
+}
+
+export interface ShinGuardRecipeData {
+    recipeType: ShinGuardRecipeType;
+    requiredLeatherType: RawLeatherShinGuardType;
+    requiredLeatherCount: number;
+    baseCannonBoneImpactDeflectionPercent: number;
+    baseFlexorTendonShieldingPercent: number;
+}
+
+export interface ActiveShinGuardBench {
+    benchId: string;
+    leatherworkerPlayerId: string;
+    benchType: ShinGuardBenchType;
+    currentDurability: number;
+    maxDurability: number;
+    isFunctional: boolean;
+}
+
+export interface CraftedHorseShinGuard {
+    shinGuardId: string;
+    recipeType: ShinGuardRecipeType;
+    finalCannonBoneImpactDeflectionPercent: number;
+    finalFlexorTendonShieldingPercent: number;
+    shinGuardStabilityPercent: number; // Scaled rating (clamped 0 to 100%, with catalog bench baselines ~16% to 100%)
+    consumedLeatherCount: number;
+    consumedLeatherType: RawLeatherShinGuardType;
+    remainingProvidedLeathers: RawLeatherShinGuardType[];
+    craftedEpochMs: number;
+}
+
+export const SHIN_GUARD_BENCH_CATALOG: Record<ShinGuardBenchType, ShinGuardBenchData> = {
+    ELDER_SHIN_GUARD_BENCH: { benchType: "ELDER_SHIN_GUARD_BENCH", maxDurability: 100, leathercraftPower: 34, baseSuccessRatePercent: 88, shinGuardStabilityBonusPercent: 15 },
+    RUNIC_OAK_SHIN_GUARD_RIG: { benchType: "RUNIC_OAK_SHIN_GUARD_RIG", maxDurability: 215, leathercraftPower: 77, baseSuccessRatePercent: 95, shinGuardStabilityBonusPercent: 25 },
+    CELESTIAL_VOID_VALKYRIE_SHIN_GUARD_SANCTUM: { benchType: "CELESTIAL_VOID_VALKYRIE_SHIN_GUARD_SANCTUM", maxDurability: 370, leathercraftPower: 138, baseSuccessRatePercent: 99, shinGuardStabilityBonusPercent: 40 },
+};
+
+export const SHIN_GUARD_RECIPE_CATALOG: Record<ShinGuardRecipeType, ShinGuardRecipeData> = {
+    NOVICE_EXPEDITION_SHIN_GUARD: { recipeType: "NOVICE_EXPEDITION_SHIN_GUARD", requiredLeatherType: "TANNED_BULL_CANNON_STRAP", requiredLeatherCount: 2, baseCannonBoneImpactDeflectionPercent: 27, baseFlexorTendonShieldingPercent: 17 },
+    WARMASTER_MITHRIL_REINFORCED_SHIN_GUARD: { recipeType: "WARMASTER_MITHRIL_REINFORCED_SHIN_GUARD", requiredLeatherType: "TEMPERED_MITHRIL_CANNON_SPLINT", requiredLeatherCount: 2, baseCannonBoneImpactDeflectionPercent: 56, baseFlexorTendonShieldingPercent: 36 },
+    CELESTIAL_VOID_VALKYRIE_SOVEREIGN_SHIN_GUARD: { recipeType: "CELESTIAL_VOID_VALKYRIE_SOVEREIGN_SHIN_GUARD", requiredLeatherType: "CELESTIAL_VOID_ASTRAL_METACARPAL_PAD", requiredLeatherCount: 2, baseCannonBoneImpactDeflectionPercent: 87, baseFlexorTendonShieldingPercent: 67 },
+};
+
+export class AncientRunicLeatherHorseShinGuardBenchEngine {
+    public static readonly DURABILITY_COST_PER_CRAFT = 10;
+
+    /**
+     * Cached static catalog maxima to prevent runtime array reallocation.
+     */
+    private static readonly MAX_BENCH_POWER = Math.max(...Object.values(SHIN_GUARD_BENCH_CATALOG).map(b => b.leathercraftPower));
+    private static readonly MAX_BENCH_BONUS = Math.max(...Object.values(SHIN_GUARD_BENCH_CATALOG).map(b => b.shinGuardStabilityBonusPercent));
+
+    /**
+     * Constructs an active horse shin guard bench instance.
+     */
+    public static constructBench(leatherworkerPlayerId: string, benchType: ShinGuardBenchType): ActiveShinGuardBench {
+        const data = SHIN_GUARD_BENCH_CATALOG[benchType] ?? SHIN_GUARD_BENCH_CATALOG.ELDER_SHIN_GUARD_BENCH;
+        return {
+            benchId: `shin_guard_bench_${crypto.randomUUID()}`,
+            leatherworkerPlayerId,
+            benchType: data.benchType,
+            currentDurability: data.maxDurability,
+            maxDurability: data.maxDurability,
+            isFunctional: true,
+        };
+    }
+
+    /**
+     * Safely samples a crypto-secure pseudorandom float strictly in [0, 1).
+     */
+    public static sampleSecureUnitRoll(): number {
+        return crypto.randomInt(0, 1_000_000_000) / 1_000_000_000;
+    }
+
+    /**
+     * Crafts horse shin guards with upfront material deduction and immutable bench cloning.
+     */
+    public static craftShinGuard(
+        bench: ActiveShinGuardBench,
+        recipeType: ShinGuardRecipeType,
+        providedLeathers: RawLeatherShinGuardType[],
+        craftRoll?: number,
+        stabilityRoll?: number,
+        currentEpochMs = Date.now()
+    ): { success: boolean; shinGuard?: CraftedHorseShinGuard; updatedBench?: ActiveShinGuardBench; remainingDurability: number; remainingProvidedLeathers: RawLeatherShinGuardType[]; reason?: string } {
+        const fallbackLeathers = Array.isArray(providedLeathers) ? [...providedLeathers] : [];
+
+        if (!bench || !bench.isFunctional || bench.currentDurability < this.DURABILITY_COST_PER_CRAFT) {
+            return {
+                success: false,
+                updatedBench: bench ? { ...bench } : undefined,
+                remainingDurability: bench?.currentDurability ?? 0,
+                remainingProvidedLeathers: fallbackLeathers,
+                reason: `Horse shin guard bench is warped or lacks durability (requires ${this.DURABILITY_COST_PER_CRAFT}).`,
+            };
+        }
+
+        const benchData = SHIN_GUARD_BENCH_CATALOG[bench.benchType];
+        if (!benchData) {
+            return { success: false, updatedBench: { ...bench }, remainingDurability: bench.currentDurability, remainingProvidedLeathers: fallbackLeathers, reason: `Unknown bench model: ${String(bench.benchType)}` };
+        }
+
+        const recipe = SHIN_GUARD_RECIPE_CATALOG[recipeType];
+        if (!recipe) {
+            return { success: false, updatedBench: { ...bench }, remainingDurability: bench.currentDurability, remainingProvidedLeathers: fallbackLeathers, reason: `Unknown horse shin guard recipe: ${String(recipeType)}` };
+        }
+
+        if (!Array.isArray(providedLeathers)) {
+            return { success: false, updatedBench: { ...bench }, remainingDurability: bench.currentDurability, remainingProvidedLeathers: [], reason: "Invalid leathers array." };
+        }
+
+        // Count matching leather materials
+        const matchingCount = providedLeathers.filter(l => l === recipe.requiredLeatherType).length;
+        if (matchingCount < recipe.requiredLeatherCount) {
+            return {
+                success: false,
+                updatedBench: { ...bench },
+                remainingDurability: bench.currentDurability,
+                remainingProvidedLeathers: fallbackLeathers,
+                reason: `Insufficient cannon straps/splints: requires ${recipe.requiredLeatherCount}x ${recipe.requiredLeatherType}, provided ${matchingCount}.`,
+            };
+        }
+
+        // Create updated bench clone
+        const updatedBench = { ...bench };
+
+        // Deduct durability on clone
+        updatedBench.currentDurability -= this.DURABILITY_COST_PER_CRAFT;
+        if (updatedBench.currentDurability < this.DURABILITY_COST_PER_CRAFT) {
+            updatedBench.currentDurability = Math.max(0, updatedBench.currentDurability);
+            updatedBench.isFunctional = false;
+        }
+
+        // Deduct materials upfront on all craft attempts
+        const remainingProvidedLeathers: RawLeatherShinGuardType[] = [];
+        let deducted = 0;
+        for (const item of providedLeathers) {
+            if (deducted < recipe.requiredLeatherCount && item === recipe.requiredLeatherType) {
+                deducted++;
+            } else {
+                remainingProvidedLeathers.push(item);
+            }
+        }
+
+        const safeCraftRoll = craftRoll !== undefined && Number.isFinite(craftRoll) ? Math.min(Math.max(craftRoll, 0), 1) : this.sampleSecureUnitRoll();
+        const successThreshold = benchData.baseSuccessRatePercent / 100;
+
+        if (safeCraftRoll > successThreshold) {
+            return {
+                success: false,
+                updatedBench,
+                remainingDurability: updatedBench.currentDurability,
+                remainingProvidedLeathers,
+                reason: `Cannon bone splint warped during high-heat tempering (roll ${safeCraftRoll.toFixed(4)} > threshold ${successThreshold.toFixed(4)}).`,
+            };
+        }
+
+        const safeStabilityRoll = stabilityRoll !== undefined && Number.isFinite(stabilityRoll) ? Math.min(Math.max(stabilityRoll, 0), 1) : this.sampleSecureUnitRoll();
+        const powerRatio = this.MAX_BENCH_POWER > 0 ? benchData.leathercraftPower / this.MAX_BENCH_POWER : 0;
+        const stabilityBonusRatio = this.MAX_BENCH_BONUS > 0 ? benchData.shinGuardStabilityBonusPercent / this.MAX_BENCH_BONUS : 0;
+
+        const stabilityBasePoints = safeStabilityRoll * 40;
+        const powerBonusPoints = powerRatio * 40;
+        const benchBonusPoints = stabilityBonusRatio * 20;
+        const rawStabilityScore = stabilityBasePoints + powerBonusPoints + benchBonusPoints;
+        const shinGuardStabilityPercent = Math.min(100, Math.max(0, Math.round(rawStabilityScore)));
+
+        const qualityMultiplier = 0.8 + (shinGuardStabilityPercent / 100) * 0.4;
+        const finalCannonBoneImpactDeflectionPercent = Math.min(100, Math.max(0, Math.round(recipe.baseCannonBoneImpactDeflectionPercent * qualityMultiplier)));
+        const finalFlexorTendonShieldingPercent = Math.min(100, Math.max(0, Math.round(recipe.baseFlexorTendonShieldingPercent * qualityMultiplier)));
+
+        const shinGuard: CraftedHorseShinGuard = {
+            shinGuardId: `shin_guard_${crypto.randomUUID()}`,
+            recipeType: recipe.recipeType,
+            finalCannonBoneImpactDeflectionPercent,
+            finalFlexorTendonShieldingPercent,
+            shinGuardStabilityPercent,
+            consumedLeatherCount: recipe.requiredLeatherCount,
+            consumedLeatherType: recipe.requiredLeatherType,
+            remainingProvidedLeathers,
+            craftedEpochMs: currentEpochMs,
+        };
+
+        return {
+            success: true,
+            shinGuard,
+            updatedBench,
+            remainingDurability: updatedBench.currentDurability,
+            remainingProvidedLeathers,
+        };
+    }
+
+    /**
+     * Maintains and repairs a horse shin guard bench instance.
+     */
+    public static maintainBench(bench: ActiveShinGuardBench, repairAmount: number): ActiveShinGuardBench {
+        if (!bench) return bench;
+        const updated = { ...bench };
+        const safeAmount = Math.max(0, repairAmount);
+        updated.currentDurability = Math.min(updated.maxDurability, updated.currentDurability + safeAmount);
+        updated.isFunctional = updated.currentDurability >= this.DURABILITY_COST_PER_CRAFT;
+        return updated;
+    }
+}
diff --git a/api/src/tests/ancientRunicLeatherHorseShinGuardBench.test.ts b/api/src/tests/ancientRunicLeatherHorseShinGuardBench.test.ts
@@ -0,0 +1,149 @@
+import { describe, it, expect } from "vitest";
+import { AncientRunicLeatherHorseShinGuardBenchEngine } from "../lib/ancientRunicLeatherHorseShinGuardBench";
+import type { ActiveShinGuardBench } from "../lib/ancientRunicLeatherHorseShinGuardBench";
+
+describe("AncientRunicLeatherHorseShinGuardBenchEngine Equestrian Cannon Bone Armor Stitching Benches", () => {
+    it("crafts Celestial Void Valkyrie Sovereign Shin Guard in Shin Guard Sanctum achieving 100% stability and returns remaining pads", () => {
+        const bench = AncientRunicLeatherHorseShinGuardBenchEngine.constructBench("leather_01", "CELESTIAL_VOID_VALKYRIE_SHIN_GUARD_SANCTUM");
+        expect(bench.benchType).toBe("CELESTIAL_VOID_VALKYRIE_SHIN_GUARD_SANCTUM");
+        expect(bench.currentDurability).toBe(370);
+
+        const initialLeathers = [
+            "CELESTIAL_VOID_ASTRAL_METACARPAL_PAD",
+            "CELESTIAL_VOID_ASTRAL_METACARPAL_PAD",
+            "CELESTIAL_VOID_ASTRAL_METACARPAL_PAD"
+        ] as any[];
+
+        const craftRes = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "CELESTIAL_VOID_VALKYRIE_SOVEREIGN_SHIN_GUARD",
+            initialLeathers,
+            0.1, // Success roll
+            1.0, // Stability roll 1.0 -> 40 + 40 + 20 = 100%
+            100000
+        );
+
+        expect(craftRes.success).toBe(true);
+        expect(craftRes.shinGuard?.recipeType).toBe("CELESTIAL_VOID_VALKYRIE_SOVEREIGN_SHIN_GUARD");
+        expect(craftRes.shinGuard?.shinGuardStabilityPercent).toBe(100);
+        expect(craftRes.shinGuard?.finalCannonBoneImpactDeflectionPercent).toBe(100); // 87 * 1.20 = 104.4 -> clamped 100%
+        expect(craftRes.shinGuard?.finalFlexorTendonShieldingPercent).toBe(80); // 67 * 1.20 = 80.4 -> 80%
+        expect(craftRes.shinGuard?.consumedLeatherCount).toBe(2);
+        expect(craftRes.shinGuard?.consumedLeatherType).toBe("CELESTIAL_VOID_ASTRAL_METACARPAL_PAD");
+        expect(craftRes.shinGuard?.remainingProvidedLeathers.length).toBe(1);
+        expect(craftRes.remainingDurability).toBe(360); // 370 - 10
+    });
+
+    it("verifies mid-range stability roll and sub-100% quality scaling on Elder shin guard bench", () => {
+        const bench = AncientRunicLeatherHorseShinGuardBenchEngine.constructBench("leather_mid", "ELDER_SHIN_GUARD_BENCH");
+        const craftRes = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "NOVICE_EXPEDITION_SHIN_GUARD",
+            ["TANNED_BULL_CANNON_STRAP", "TANNED_BULL_CANNON_STRAP"],
+            0.1,
+            0.5
+        );
+
+        expect(craftRes.success).toBe(true);
+        expect(craftRes.shinGuard?.shinGuardStabilityPercent).toBe(37);
+        expect(craftRes.shinGuard?.finalCannonBoneImpactDeflectionPercent).toBe(26);
+        expect(craftRes.shinGuard?.finalFlexorTendonShieldingPercent).toBe(16);
+        expect(craftRes.remainingDurability).toBe(90); // 100 - 10
+    });
+
+    it("fails when craft roll exceeds threshold, deducting materials upfront and bench durability on clone", () => {
+        const bench = AncientRunicLeatherHorseShinGuardBenchEngine.constructBench("leather_fail", "ELDER_SHIN_GUARD_BENCH");
+        const initialDurability = bench.currentDurability;
+
+        const craftRes = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "NOVICE_EXPEDITION_SHIN_GUARD",
+            ["TANNED_BULL_CANNON_STRAP", "TANNED_BULL_CANNON_STRAP", "TANNED_BULL_CANNON_STRAP"],
+            0.99 // Fails (threshold is 0.88)
+        );
+
+        expect(craftRes.success).toBe(false);
+        expect(craftRes.reason).toContain("Cannon bone splint warped");
+        expect(craftRes.remainingProvidedLeathers.length).toBe(1); // 3 provided - 2 deducted upfront = 1 remaining
+        expect(craftRes.remainingDurability).toBe(initialDurability - 10);
+        // Original bench remains untouched
+        expect(bench.currentDurability).toBe(initialDurability);
+    });
+
+    it("rejects craft when required leather materials are insufficient without deducting durability", () => {
+        const bench = AncientRunicLeatherHorseShinGuardBenchEngine.constructBench("leather_short", "RUNIC_OAK_SHIN_GUARD_RIG");
+        const initialDurability = bench.currentDurability;
+
+        const craftRes = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "WARMASTER_MITHRIL_REINFORCED_SHIN_GUARD",
+            ["TEMPERED_MITHRIL_CANNON_SPLINT"] // Needs 2, only 1 provided
+        );
+
+        expect(craftRes.success).toBe(false);
+        expect(craftRes.reason).toContain("Insufficient cannon straps/splints");
+        expect(craftRes.remainingDurability).toBe(initialDurability);
+        expect(craftRes.remainingProvidedLeathers.length).toBe(1);
+    });
+
+    it("rejects craft when bench durability is below cost and marks non-functional", () => {
+        const brokenBench: ActiveShinGuardBench = {
+            benchId: "broken_01",
+            leatherworkerPlayerId: "player_x",
+            benchType: "ELDER_SHIN_GUARD_BENCH",
+            currentDurability: 5, // Below 10
+            maxDurability: 100,
+            isFunctional: false,
+        };
+
+        const craftRes = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            brokenBench,
+            "NOVICE_EXPEDITION_SHIN_GUARD",
+            ["TANNED_BULL_CANNON_STRAP", "TANNED_BULL_CANNON_STRAP"]
+        );
+
+        expect(craftRes.success).toBe(false);
+        expect(craftRes.reason).toContain("lacks durability");
+        expect(craftRes.remainingDurability).toBe(5);
+        expect(craftRes.remainingProvidedLeathers.length).toBe(2); // No materials deducted
+    });
+
+    it("maintains bench and restores durability and functional state", () => {
+        const damagedBench: ActiveShinGuardBench = {
+            benchId: "dmg_01",
+            leatherworkerPlayerId: "player_y",
+            benchType: "RUNIC_OAK_SHIN_GUARD_RIG",
+            currentDurability: 0,
+            maxDurability: 215,
+            isFunctional: false,
+        };
+
+        const repaired = AncientRunicLeatherHorseShinGuardBenchEngine.maintainBench(damagedBench, 100);
+        expect(repaired.currentDurability).toBe(100);
+        expect(repaired.isFunctional).toBe(true);
+
+        // Does not exceed max durability
+        const overRepaired = AncientRunicLeatherHorseShinGuardBenchEngine.maintainBench(repaired, 500);
+        expect(overRepaired.currentDurability).toBe(215);
+    });
+
+    it("defensively rejects invalid recipe, non-array leathers, or invalid bench models", () => {
+        const bench = AncientRunicLeatherHorseShinGuardBenchEngine.constructBench("p_def", "ELDER_SHIN_GUARD_BENCH");
+
+        const invalidRecipe = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "INVALID_RECIPE" as any,
+            ["TANNED_BULL_CANNON_STRAP", "TANNED_BULL_CANNON_STRAP"]
+        );
+        expect(invalidRecipe.success).toBe(false);
+        expect(invalidRecipe.reason).toContain("Unknown horse shin guard recipe");
+
+        const invalidLeathers = AncientRunicLeatherHorseShinGuardBenchEngine.craftShinGuard(
+            bench,
+            "NOVICE_EXPEDITION_SHIN_GUARD",
+            null as any
+        );
+        expect(invalidLeathers.success).toBe(false);
+        expect(invalidLeathers.reason).toContain("Invalid leathers array");
+    });
+});