/**
 * Tekton Nakama Server Runtime Module
 * 
 * This module provides secure admin operations via RPC calls.
 * Deploy this to your Nakama server's runtime directory.
 */

// Initialize RPC endpoints
function InitModule(ctx, logger, nk, initializer) {
    // Admin RPCs
    initializer.registerRpc("admin_kick_player", rpcAdminKickPlayer);
    initializer.registerRpc("admin_ban_player", rpcAdminBanPlayer);
    initializer.registerRpc("admin_unban_player", rpcAdminUnbanPlayer);
    initializer.registerRpc("admin_get_ban_list", rpcAdminGetBanList);
    initializer.registerRpc("admin_get_server_stats", rpcAdminGetServerStats);
    initializer.registerRpc("admin_get_player_list", rpcAdminGetPlayerList);
    initializer.registerRpc("admin_end_match", rpcAdminEndMatch);
    initializer.registerRpc("admin_set_user_role", rpcAdminSetUserRole);
    initializer.registerRpc("admin_list_users", rpcAdminListUsers);
    initializer.registerRpc("admin_delete_users", rpcAdminDeleteUsers);
    initializer.registerRpc("admin_topup_gold", rpcAdminTopupGold);

    // User management RPCs
    initializer.registerRpc("get_user_profile", rpcGetUserProfile);
    initializer.registerRpc("update_user_profile", rpcUpdateUserProfile);
    
    // Store RPCs
    initializer.registerRpc("purchase_item", rpcPurchaseItem);
    initializer.registerRpc("get_shop_catalog", rpcGetShopCatalog);
    initializer.registerRpc("buy_currency", rpcBuyCurrency);
    
    // Leaderboard RPCs
    initializer.registerRpc("get_leaderboard_stats", rpcGetLeaderboardStats);
    initializer.registerRpc("admin_update_stats", rpcAdminUpdateStats);
    initializer.registerRpc("admin_delete_stats", rpcAdminDeleteStats);
    initializer.registerRpc("admin_sync_leaderboard", rpcAdminSyncLeaderboard);
    // Client-accessible score submission (authoritative leaderboard requires server-side writes)
    initializer.registerRpc("submit_score", rpcSubmitScore);
    initializer.registerRpc("sync_leaderboard", rpcSyncLeaderboard);
    initializer.registerRpc("change_credentials", rpcChangeCredentials);
    initializer.registerRpc("reset_stats", rpcResetStats);

    // Create default native leaderboard
    // id: "global_high_score", authoritative: true, sort: "desc", operator: "best", reset: None
    try { nk.leaderboardCreate("global_high_score", true, "desc", "best", null, {}); } catch(e) {}

    logger.info("Tekton admin module loaded");
}

// =============================================================================
// Authorization Helpers
// =============================================================================

var ADMIN_ROLES = ["admin", "moderator", "owner"];

// =============================================================================
// Shop Catalog Definitions
// =============================================================================
// To add a new item: append ONE entry to SHOP_CATALOG_DEFS.
// Fields:
//   id        (String)  — must match item_id in game inventory + SkinManager
//   name      (String)  — display name shown in shop
//   category  (String)  — "head" | "costume" | "glove" | "accessory"
//   gold      (Number)  — gold price  (0 = not sold for gold)
//   star      (Number)  — star price  (0 = not sold for star)
//   rarity    (String)  — "Common" | "Rare" | "Epic" | "Legendary"
//   character (String)  — (optional) which character the skin targets, e.g. "Oldpop"

// [BEGIN_SHOP_CATALOG_DEFS]
var SHOP_CATALOG_DEFS = [
    // ── HEAD ────────────────────────────────────────────────────────────
    { id: "oldpop-blue-hat", name: "Oldpop Blue Hat", category: "head", gold: 100, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-green-hat", name: "Oldpop Green Hat", category: "head", gold: 100, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-red-hat", name: "Oldpop Red Hat", category: "head", gold: 100, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-yellow-hat", name: "Oldpop Yellow Hat", category: "head", gold: 100, star: 0, rarity: "Common", character: "Oldpop" },
    // ── COSTUME ────────────────────────────────────────────────────────────
    { id: "oldpop-og-pant", name: "Copper OG Pant", category: "costume", gold: 0, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-grey-pant", name: "Copper Grey Pant", category: "costume", gold: 150, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-red-pant", name: "Copper Red Pant", category: "costume", gold: 150, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-yellow-pant", name: "Copper Yellow Pant", category: "costume", gold: 150, star: 0, rarity: "Common", character: "Oldpop" },
    // ── GLOVE ────────────────────────────────────────────────────────────
    { id: "oldpop-blue-gloves", name: "Oldpop Blue Gloves", category: "glove", gold: 75, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-green-gloves", name: "Oldpop Green Gloves", category: "glove", gold: 75, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-red-gloves", name: "Oldpop Red Gloves", category: "glove", gold: 75, star: 0, rarity: "Common", character: "Oldpop" },
    { id: "oldpop-yellow-gloves", name: "Oldpop Yellow Gloves", category: "glove", gold: 75, star: 0, rarity: "Common", character: "Oldpop" },
];
// [END_SHOP_CATALOG_DEFS]

/** Groups SHOP_CATALOG_DEFS by category for the shop RPC response. */
function buildShopCatalog() {
    var catalog = {};
    for (var i = 0; i < SHOP_CATALOG_DEFS.length; i++) {
        var def = SHOP_CATALOG_DEFS[i];
        var cat = def.category;
        if (!catalog[cat]) catalog[cat] = [];
        var entry = {
            id:     def.id,
            name:   def.name,
            gold:   def.gold   || 0,
            star:   def.star   || 0,
            rarity: def.rarity || "Common"
        };
        if (def.character) entry.character = def.character;
        catalog[cat].push(entry);
    }
    return catalog;
}


function isAdmin(ctx, nk) {
    if (!ctx.userId) return false;

    try {
        var account = nk.accountGetId(ctx.userId);
        var metadata;
        if (typeof account.user.metadata === "string") {
            metadata = JSON.parse(account.user.metadata || "{}");
        } else {
            metadata = account.user.metadata || {};
        }
        var role = metadata.role || "";
        return ADMIN_ROLES.indexOf(role) !== -1;
    } catch (e) {
        return false;
    }
}

function isMatchHost(ctx, nk, matchId) {
    if (!ctx.userId || !matchId) return false;

    try {
        // Get match state to check host
        var match = nk.matchGet(matchId);
        if (!match) return false;

        // The first user to join (presence) is typically the host
        // This logic may need adjustment based on your match handler
        var state = JSON.parse(match.state || "{}");
        return state.hostUserId === ctx.userId;
    } catch (e) {
        return false;
    }
}

function requireAdmin(ctx, nk) {
    if (!isAdmin(ctx, nk)) {
        throw new Error("Admin privileges required");
    }
}

function requireAdminOrHost(ctx, nk, matchId) {
    if (!isAdmin(ctx, nk) && !isMatchHost(ctx, nk, matchId)) {
        throw new Error("Admin or host privileges required");
    }
}

// =============================================================================
// Admin RPCs
// =============================================================================

function rpcAdminKickPlayer(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    requireAdminOrHost(ctx, nk, request.match_id);

    // Can't kick yourself
    if (request.user_id === ctx.userId) {
        throw new Error("Cannot kick yourself");
    }

    try {
        // Signal the match to kick the player
        nk.matchSignal(request.match_id, JSON.stringify({
            action: "kick",
            user_id: request.user_id,
            reason: request.reason || "Kicked by admin"
        }));

        logger.info("Player " + request.user_id + " kicked from match " + request.match_id + " by " + ctx.userId);

        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to kick player: " + e);
        throw new Error("Failed to kick player");
    }
}

function rpcAdminBanPlayer(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    // Only full admins can ban (not just match hosts)
    requireAdmin(ctx, nk);

    if (request.user_id === ctx.userId) {
        throw new Error("Cannot ban yourself");
    }

    try {
        // Get target user's account
        var targetAccount = nk.accountGetId(request.user_id);
        var metadata = JSON.parse(targetAccount.user.metadata || "{}");

        // Don't allow banning other admins
        if (ADMIN_ROLES.indexOf(metadata.role || "") !== -1) {
            throw new Error("Cannot ban an admin");
        }

        // Set ban in metadata
        var banExpires = request.duration_hours && request.duration_hours > 0
            ? new Date(Date.now() + request.duration_hours * 60 * 60 * 1000).toISOString()
            : null;

        metadata.banned = true;
        metadata.ban_reason = request.reason || "Banned by admin";
        if (banExpires) {
            metadata.ban_expires = banExpires;
        }

        nk.accountUpdateId(request.user_id, null, null, null, null, null, null, JSON.stringify(metadata));

        // Also kick from current match if specified
        if (request.match_id) {
            nk.matchSignal(request.match_id, JSON.stringify({
                action: "kick",
                user_id: request.user_id,
                reason: "Banned: " + (request.reason || "")
            }));
        }

        // Store in ban list (for quick lookup)
        var banRecord = {
            user_id: request.user_id,
            username: targetAccount.user.username,
            banned_by: ctx.userId,
            banned_at: new Date().toISOString(),
            reason: request.reason,
            expires: banExpires
        };

        nk.storageWrite([{
            collection: "bans",
            key: request.user_id,
            userId: "00000000-0000-0000-0000-000000000000", // System-owned
            value: banRecord,
            permissionRead: 2, // Public read
            permissionWrite: 0 // No one can write (except server)
        }]);

        logger.warn("Player " + request.user_id + " banned by " + ctx.userId + ". Reason: " + request.reason);

        return JSON.stringify({ success: true, ban: banRecord });
    } catch (e) {
        logger.error("Failed to ban player: " + e);
        throw new Error("Failed to ban player: " + e);
    }
}

function rpcAdminUnbanPlayer(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    requireAdmin(ctx, nk);

    try {
        // Get target user's account
        var targetAccount = nk.accountGetId(request.user_id);
        var metadata = JSON.parse(targetAccount.user.metadata || "{}");

        // Remove ban
        delete metadata.banned;
        delete metadata.ban_reason;
        delete metadata.ban_expires;

        nk.accountUpdateId(request.user_id, null, null, null, null, null, null, JSON.stringify(metadata));

        // Remove from ban list
        nk.storageDelete([{
            collection: "bans",
            key: request.user_id,
            userId: "00000000-0000-0000-0000-000000000000"
        }]);

        logger.info("Player " + request.user_id + " unbanned by " + ctx.userId);

        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to unban player: " + e);
        throw new Error("Failed to unban player");
    }
}

function rpcAdminGetBanList(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);

    try {
        var result = nk.storageList(
            "00000000-0000-0000-0000-000000000000",
            "bans",
            100,
            ""
        );

        var bans = result.objects ? result.objects.map(function(obj) { return obj.value; }) : [];

        return JSON.stringify({ bans: bans });
    } catch (e) {
        logger.error("Failed to get ban list: " + e);
        return JSON.stringify({ bans: [] });
    }
}

function rpcAdminGetServerStats(ctx, logger, nk, payload) {
    var request = JSON.parse(payload || "{}");

    if (request.match_id) {
        requireAdminOrHost(ctx, nk, request.match_id);
    } else {
        requireAdmin(ctx, nk);
    }

    try {
        // Get server-wide stats
        var matches = nk.matchList(100, true, null, null, null, null);
        var activeMatchCount = matches ? matches.length : 0;

        var totalPlayers = 0;
        if (matches) {
            for (var i = 0; i < matches.length; i++) {
                totalPlayers += matches[i].size || 0;
            }
        }

        var stats = {
            active_matches: activeMatchCount,
            total_players: totalPlayers,
            server_time: new Date().toISOString()
        };

        // If specific match requested, include match details
        if (request.match_id) {
            try {
                var match = nk.matchGet(request.match_id);
                if (match) {
                    stats.match = {
                        id: match.matchId,
                        size: match.size,
                        tick_rate: match.tickRate,
                        authoritative: match.authoritative
                    };
                }
            } catch (e) {
                // Match not found
            }
        }

        return JSON.stringify(stats);
    } catch (e) {
        logger.error("Failed to get server stats: " + e);
        throw new Error("Failed to get server stats");
    }
}

function rpcAdminGetPlayerList(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    requireAdminOrHost(ctx, nk, request.match_id);

    try {
        var match = nk.matchGet(request.match_id);
        if (!match) {
            throw new Error("Match not found");
        }

        // Get player details
        var players = [];

        // Note: In actual implementation, you'd need to track presences
        // This is a simplified version - adjust based on your match handler

        return JSON.stringify({ players: players });
    } catch (e) {
        logger.error("Failed to get player list: " + e);
        throw new Error("Failed to get player list");
    }
}

function rpcAdminEndMatch(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    requireAdminOrHost(ctx, nk, request.match_id);

    try {
        // Signal match to end
        nk.matchSignal(request.match_id, JSON.stringify({
            action: "end_match",
            reason: request.reason || "Ended by admin"
        }));

        logger.info("Match " + request.match_id + " ended by " + ctx.userId);

        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to end match: " + e);
        throw new Error("Failed to end match");
    }
}

function rpcAdminSetUserRole(ctx, logger, nk, payload) {
    var request = JSON.parse(payload);

    // Only owner/super-admin can set roles
    var callerAccount = nk.accountGetId(ctx.userId);
    var callerMetadata = JSON.parse(callerAccount.user.metadata || "{}");

    if (callerMetadata.role !== "owner") {
        throw new Error("Only owners can modify user roles");
    }

    var validRoles = ["player", "moderator", "admin"];
    if (validRoles.indexOf(request.role) === -1) {
        throw new Error("Invalid role");
    }

    try {
        var targetAccount = nk.accountGetId(request.user_id);
        var metadata = JSON.parse(targetAccount.user.metadata || "{}");

        metadata.role = request.role;

        nk.accountUpdateId(request.user_id, null, null, null, null, null, null, JSON.stringify(metadata));

        logger.info("User " + request.user_id + " role set to " + request.role + " by " + ctx.userId);

        return JSON.stringify({ success: true, role: request.role });
    } catch (e) {
        logger.error("Failed to set user role: " + e);
        throw new Error("Failed to set user role");
    }
}

// =============================================================================
// Store / Economy RPCs
// =============================================================================

function rpcGetShopCatalog(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    return JSON.stringify({ catalog: buildShopCatalog() });
}

function rpcAdminTopupGold(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);
    try {
        nk.walletUpdate(ctx.userId, { "gold": 999999 }, {}, true);
        logger.info("Admin gold top-up applied for user " + ctx.userId);
        return JSON.stringify({ success: true, gold_added: 999999 });
    } catch (e) {
        logger.error("Top-up failed: " + e);
        throw new Error("Top-up failed: " + e);
    }
}

function rpcBuyCurrency(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    
    var request = JSON.parse(payload);
    var packageId = request.package_id;
    
    var changeset = { "gold": 0, "star": 0 };
    
    if (packageId === "gold_100") changeset["gold"] = 100;
    else if (packageId === "gold_500") changeset["gold"] = 550;
    else if (packageId === "gold_1000") changeset["gold"] = 1150;
    else if (packageId === "gold_2000") changeset["gold"] = 2400;
    else if (packageId === "gold_5000") changeset["gold"] = 6250;
    else if (packageId === "gold_10000") changeset["gold"] = 13000;
    else if (packageId === "star_100") { changeset["star"] = 100; changeset["gold"] = -500; }
    else if (packageId === "star_250") { changeset["star"] = 250; changeset["gold"] = -1100; }
    else if (packageId === "star_600") { changeset["star"] = 600; changeset["gold"] = -2500; }
    else throw new Error("Invalid package ID");
    
    try {
        nk.walletUpdate(ctx.userId, changeset, {}, true);
        logger.info("User " + ctx.userId + " bought currency package " + packageId);
        return JSON.stringify({ success: true, package_id: packageId });
    } catch (e) {
        logger.error("Currency purchase failed: " + e.message);
        throw new Error("Currency purchase failed: " + e.message);
    }
}

function rpcPurchaseItem(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    
    var request = JSON.parse(payload);
    var itemId = request.item_id;
    var priceGold = request.price_gold || 0;
    var priceStar = request.price_star || 0;
    var category = request.category || "accessory"; // head, costume, glove, accessory

    if (!itemId) throw new Error("Item ID required");

    try {
        var changeset = {};
        if (priceGold > 0) changeset["gold"] = -priceGold;
        if (priceStar > 0) changeset["star"] = -priceStar;

        // Check wallet and deduct
        // nk.walletUpdate throws an error if insufficient funds
        nk.walletUpdate(ctx.userId, changeset, {}, true);

        // Record purchase in inventory
        var inventoryObj = {
            collection: "inventory",
            key: itemId,
            userId: ctx.userId,
            value: { category: category, purchased_at: new Date().toISOString() },
            permissionRead: 1,
            permissionWrite: 0
        };
        nk.storageWrite([inventoryObj]);

        logger.info("User " + ctx.userId + " purchased " + itemId);
        return JSON.stringify({ success: true, item: itemId });
    } catch (e) {
        logger.error("Purchase failed: " + e.message);
        throw new Error("Purchase failed: " + e.message);
    }
}

// =============================================================================
// User Profile RPCs
// =============================================================================

function rpcGetUserProfile(ctx, logger, nk, payload) {
    var request = JSON.parse(payload || "{}");
    var targetUserId = request.user_id || ctx.userId;

    try {
        var account = nk.accountGetId(targetUserId);
        var metadata = JSON.parse(account.user.metadata || "{}");

        // Check if banned
        if (metadata.banned && targetUserId === ctx.userId) {
            // Check if ban expired
            if (metadata.ban_expires) {
                var expiresAt = new Date(metadata.ban_expires);
                if (expiresAt <= new Date()) {
                    // Ban expired, remove it
                    delete metadata.banned;
                    delete metadata.ban_reason;
                    delete metadata.ban_expires;
                    nk.accountUpdateId(targetUserId, null, null, null, null, null, null, JSON.stringify(metadata));
                } else {
                    throw new Error("Account banned until " + metadata.ban_expires + ". Reason: " + metadata.ban_reason);
                }
            } else {
                throw new Error("Account permanently banned. Reason: " + metadata.ban_reason);
            }
        }

        return JSON.stringify({
            user_id: account.user.id,
            username: account.user.username,
            display_name: account.user.displayName,
            avatar_url: account.user.avatarUrl,
            create_time: account.user.createTime,
            role: metadata.role || "player"
        });
    } catch (e) {
        throw e;
    }
}

function rpcUpdateUserProfile(ctx, logger, nk, payload) {
    if (!ctx.userId) {
        throw new Error("Not authenticated");
    }

    var request = JSON.parse(payload);

    try {
        nk.accountUpdateId(
            ctx.userId,
            null, // username
            request.display_name || null,
            null, // timezone
            null, // location
            null, // lang
            request.avatar_url || null,
            null // metadata
        );

        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to update profile: " + e);
        throw new Error("Failed to update profile");
    }
}

// =============================================================================
// Leaderboard RPCs
// =============================================================================

function rpcGetLeaderboardStats(ctx, logger, nk, payload) {
    try {
        var limit = 50;
        var records = nk.leaderboardRecordsList("global_high_score", null, limit, "");
        var leaderboardData = [];
        
        var ownerRecords = records.records || [];
        for (var i = 0; i < ownerRecords.length; i++) {
            var record = ownerRecords[i];
            var metadata = {};
            try { metadata = JSON.parse(record.metadata || "{}"); } catch (e) {}
            
            leaderboardData.push({
                user_id: record.ownerId,
                username: record.username,
                display_name: record.displayName || record.username,
                avatar_url: metadata.avatar_url || "",
                loadout_character: metadata.loadout_character || "Copper",
                high_score: record.score || 0,
                games_played: metadata.games_played || 0,
                games_won: metadata.games_won || 0
            });
        }
        
        return JSON.stringify({ leaderboard: leaderboardData });
    } catch (e) {
        logger.error("Failed to get native leaderboard stats: " + e);
        // Fallback to storage-based if native fails (e.g. not created yet)
        return JSON.stringify({ leaderboard: [] });
    }
}

// Any authenticated user can submit their own score (server writes on their behalf)
function rpcSubmitScore(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    try {
        var request = JSON.parse(payload || "{}");
        var score = parseInt(request.score) || 0;
        var account = nk.accountGetId(ctx.userId);
        var metadata = {
            games_played: request.games_played || 0,
            games_won: request.games_won || 0,
            avatar_url: account.user.avatarUrl || request.avatar_url || "",
            loadout_character: request.loadout_character || "Copper"
        };
        nk.leaderboardRecordWrite(
            "global_high_score",
            ctx.userId,
            account.user.username,
            score,
            0,
            metadata
        );
        logger.info("Score submitted for user " + ctx.userId + ": " + score);
        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to submit score for " + ctx.userId + ": " + e);
        throw new Error("Failed to submit score: " + e);
    }
}

// Any authenticated user can trigger a bulk sync (reads all public stats, populates leaderboard)
function rpcSyncLeaderboard(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    try {
        var result = nk.storageList(null, "stats", 100, "");
        var statsObjects = result.objects || [];
        var userGroup = {};
        
        for (var i = 0; i < statsObjects.length; i++) {
            var obj = statsObjects[i];
            var userId = obj.userId;
            var value;
            try {
                value = (typeof obj.value === "string") ? JSON.parse(obj.value) : obj.value;
            } catch (e) { continue; }
            if (!value) continue;
            
            if (!userGroup[userId]) {
                userGroup[userId] = {
                    high_score: value.high_score || 0,
                    games_played: value.games_played || 0,
                    games_won: value.games_won || 0,
                    avatar_url: value.avatar_url || "",
                    loadout_character: value.loadout_character || ""
                };
            } else {
                userGroup[userId].high_score = Math.max(userGroup[userId].high_score, value.high_score || 0);
                userGroup[userId].games_played = Math.max(userGroup[userId].games_played, value.games_played || 0);
                userGroup[userId].games_won = Math.max(userGroup[userId].games_won, value.games_won || 0);
            }
            
            // Prioritize avatar and character from game_stats or if current is empty
            if (obj.key === "game_stats" || !userGroup[userId].avatar_url) {
                if (value.avatar_url) userGroup[userId].avatar_url = value.avatar_url;
                if (value.loadout_character) userGroup[userId].loadout_character = value.loadout_character;
            }
        }
        
        // Phase 2: Read profiles collection to get loadout and avatars!
        var profileResult = nk.storageList(null, "profiles", 100, "");
        var profileObjects = profileResult.objects || [];
        for (var i = 0; i < profileObjects.length; i++) {
            var obj = profileObjects[i];
            var userId = obj.userId;
            if (obj.key !== "profile") continue;
            var value;
            try {
                value = (typeof obj.value === "string") ? JSON.parse(obj.value) : obj.value;
            } catch (e) { continue; }
            
            if (!userGroup[userId]) {
                userGroup[userId] = {
                    high_score: 0, games_played: 0, games_won: 0,
                    avatar_url: "", loadout_character: ""
                };
            }
            // If the profile has avatar or loadout, merge them. Natively preferred over empty
            if (value.avatar_url && !userGroup[userId].avatar_url) userGroup[userId].avatar_url = value.avatar_url;
            if (value.loadout_character && !userGroup[userId].loadout_character) userGroup[userId].loadout_character = value.loadout_character;
        }
        
        var count = 0;
        var debugLogs = [];
        for (var uid in userGroup) {
            try {
                var stats = userGroup[uid];
                var account = nk.accountGetId(uid);
                var meta = { 
                    games_played: stats.games_played || 0, 
                    games_won: stats.games_won || 0, 
                    avatar_url: stats.avatar_url || account.user.avatarUrl || "res://assets/graphics/character_selection/sc_characters/sc_copper.png",
                    loadout_character: stats.loadout_character || "Copper"
                };
                nk.leaderboardRecordWrite("global_high_score", uid, account.user.username, stats.high_score, 0, meta);
                count++;
            } catch (inner) {
                debugLogs.push("Error user " + uid + ": " + inner);
                logger.error("Failed to sync record for " + uid + ": " + inner);
            }
        }
        logger.info("Synced " + count + " records to leaderboard by user " + ctx.userId);
        return JSON.stringify({ success: true, synced: count, objects_found: statsObjects.length, debug: debugLogs });
    } catch (e) {
        logger.error("Leaderboard sync failed: " + e);
        throw new Error("Sync failed: " + e);
    }
}

// Change Email / Password securely
function rpcChangeCredentials(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    var req = {};
    try { req = JSON.parse(payload || "{}"); } catch (e) {}
    
    var account = nk.accountGetId(ctx.userId);
    
    // If not a guest (has email), verify current password and unlink
    if (account.email) {
        if (!req.current_password) throw new Error("Current password required");
        try {
            nk.authenticateEmail(account.email, req.current_password, false);
        } catch (e) {
            throw new Error("Incorrect current password.");
        }
        nk.unlinkEmail(ctx.userId, account.email, req.current_password);
    }
    
    try {
        nk.linkEmail(ctx.userId, req.new_email, req.new_password);
    } catch (e) {
        // Safe rollback
        if (account.email) nk.linkEmail(ctx.userId, account.email, req.current_password);
        throw new Error("Failed to set new credentials: " + e.message);
    }
    
    return JSON.stringify({ success: true });
}

// Reset Game Stats
function rpcResetStats(ctx, logger, nk, payload) {
    if (!ctx.userId) throw new Error("Not authenticated");
    var account = nk.accountGetId(ctx.userId);
    
    // Delete native leaderboard rank
    try { nk.leaderboardRecordDelete("global_high_score", ctx.userId); } catch (e) {}
    
    // Wipe storage stats
    var zeros = { games_played: 0, games_won: 0, high_score: 0, total_kills: 0, total_deaths: 0 };
    nk.storageWrite([{
        collection: "stats",
        key: "game_stats",
        userId: ctx.userId,
        value: zeros,
        permissionRead: 2,
        permissionWrite: 1
    }]);
    
    return JSON.stringify({ success: true });
}

// =============================================================================
// Admin User Management RPCs
// =============================================================================

function rpcAdminListUsers(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);

    try {
        var users = [];
        var rows = nk.sqlQuery("SELECT id, username, display_name, metadata, create_time FROM users WHERE id != '00000000-0000-0000-0000-000000000000' ORDER BY create_time DESC LIMIT 500", []);
        
        for (var i = 0; i < rows.length; i++) {
            var row = rows[i];
            var metadata = {};
            try { metadata = JSON.parse(row.metadata || "{}"); } catch(e) {}
            users.push({
                user_id: row.id,
                username: row.username || "",
                display_name: row.display_name || row.username || "",
                create_time: row.create_time,
                role: metadata.role || "player",
                banned: metadata.banned || false,
                ban_reason: metadata.ban_reason || ""
            });
        }

        return JSON.stringify({ users: users, count: users.length });
    } catch (e) {
        logger.error("Failed to list users: " + e);
        throw new Error("Failed to list users: " + e);
    }
}

function rpcAdminDeleteUsers(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);

    var request = JSON.parse(payload);
    var userIds = request.user_ids || [];

    if (userIds.length === 0) {
        throw new Error("No user IDs provided");
    }

    // Don't allow deleting yourself
    for (var i = 0; i < userIds.length; i++) {
        if (userIds[i] === ctx.userId) {
            throw new Error("Cannot delete your own account");
        }
    }

    var deleted = [];
    var failed = [];

    for (var j = 0; j < userIds.length; j++) {
        var uid = userIds[j];
        try {
            // Check if target is admin — don't allow deleting admins
            var account = nk.accountGetId(uid);
            var meta = {};
            try { meta = JSON.parse(account.user.metadata || "{}"); } catch(e) {}
            if (ADMIN_ROLES.indexOf(meta.role || "") !== -1) {
                failed.push({ user_id: uid, reason: "Cannot delete admin account" });
                continue;
            }
            nk.accountDeleteId(uid, false);
            deleted.push(uid);
            logger.warn("User " + uid + " deleted by " + ctx.userId);
        } catch (e) {
            failed.push({ user_id: uid, reason: "" + e });
        }
    }

    return JSON.stringify({ success: true, deleted: deleted, failed: failed });
}

function rpcAdminUpdateStats(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);

    var request = JSON.parse(payload);
    var targetUserId = request.user_id;
    var stats = request.stats; // { high_score: X, games_played: Y, games_won: Z }

    if (!targetUserId || !stats) {
        throw new Error("User ID and stats are required");
    }

    try {
        // 1. Update Storage (priority: game_stats)
        nk.storageWrite([{
            collection: "stats",
            key: "game_stats",
            userId: targetUserId,
            value: JSON.stringify(stats),
            permissionRead: 1, // Public read
            permissionWrite: 0
        }]);

        // 2. Update Native Leaderboard
        var account = nk.accountGetId(targetUserId);
        var score = stats.high_score || 0;
        var subscore = 0;
        var metadata = {
            games_played: stats.games_played || 0,
            games_won: stats.games_won || 0,
            avatar_url: account.user.avatarUrl || "",
            loadout_character: stats.loadout_character || "Copper"
        };

        nk.leaderboardRecordWrite("global_high_score", targetUserId, account.user.username, score, subscore, metadata);

        logger.info("Stats updated for user " + targetUserId + " by admin " + ctx.userId + " (game_stats + Native)");
        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to update stats: " + e);
        throw new Error("Failed to update stats: " + e);
    }
}

function rpcAdminDeleteStats(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);

    var request = JSON.parse(payload);
    var targetUserId = request.user_id;

    if (!targetUserId) {
        throw new Error("User ID is required");
    }

    try {
        // 1. Delete Storage (Both keys)
        nk.storageDelete([
            { collection: "stats", key: "stats", userId: targetUserId },
            { collection: "stats", key: "game_stats", userId: targetUserId }
        ]);

        // 2. Delete Native Leaderboard Record
        nk.leaderboardRecordDelete("global_high_score", targetUserId);

        logger.info("Stats deleted for user " + targetUserId + " by admin " + ctx.userId);
        return JSON.stringify({ success: true });
    } catch (e) {
        logger.error("Failed to delete stats: " + e);
        throw new Error("Failed to delete stats");
    }
}

function rpcAdminSyncLeaderboard(ctx, logger, nk, payload) {
    requireAdmin(ctx, nk);
    
    try {
        var result = nk.storageList(null, "stats", 100, "");
        var statsObjects = result.objects || [];
        var userGroup = {}; // [userId] = { highScore, gamesPlayed, gamesWon, avatar }
        
        // Phase 1: Group and merge
        for (var i = 0; i < statsObjects.length; i++) {
            var obj = statsObjects[i];
            var userId = obj.userId;
            var key = obj.key; // "stats" or "game_stats"
            var value;
            
            try {
                value = JSON.parse(obj.value || "{}");
            } catch (jsonErr) {
                logger.error("Skipping key " + key + " for user " + userId + " due to corrupt JSON");
                continue;
            }
            
            if (!userGroup[userId]) {
                userGroup[userId] = {
                    high_score: value.high_score || 0,
                    games_played: value.games_played || 0,
                    games_won: value.games_won || 0,
                    avatar_url: "",
                    loadout_character: value.loadout_character || "Copper"
                };
            } else {
                // Merge logic: sum counts, max high score
                userGroup[userId].high_score = Math.max(userGroup[userId].high_score, value.high_score || 0);
                userGroup[userId].games_played += (value.games_played || 0);
                userGroup[userId].games_won += (value.games_won || 0);
            }
            
            // Prioritize avatar and character from game_stats
            if (key === "game_stats" || !userGroup[userId].avatar_url) {
                try {
                    if (value.avatar_url) userGroup[userId].avatar_url = value.avatar_url;
                    if (value.loadout_character) userGroup[userId].loadout_character = value.loadout_character;
                } catch (e) {}
            }
        }
        
        // Phase 2: Write to native leaderboard
        var count = 0;
        for (var userId in userGroup) {
            try {
                var stats = userGroup[userId];
                var account = nk.accountGetId(userId);
                
                var metadata = {
                    games_played: stats.games_played,
                    games_won: stats.games_won,
                    avatar_url: stats.avatar_url || account.user.avatarUrl || "",
                    loadout_character: stats.loadout_character || "Copper"
                };
                
                nk.leaderboardRecordWrite("global_high_score", userId, account.user.username, stats.high_score, 0, metadata);
                count++;
            } catch (inner) {
                logger.error("Failed to sync merged record for " + userId + ": " + inner);
            }
        }
        
        return JSON.stringify({ success: true, synced: count });
    } catch (e) {
        logger.error("Leaderboard sync failed: " + e);
        throw new Error("Sync failed: " + e);
    }
}

// Before login hook to check ban status
function beforeAuthenticateEmail(ctx, logger, nk, data) {
    // Can't check ban before auth, so we check in afterAuthenticate
    return data;
}