import java.sql.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

/**
 * Delete legacy lobster menu tree (root menu_id=2951, path=lobster) from tenant sys_menu.
 * Keeps the canonical tree under menu_id=29900 (path=/lobster).
 */
public class DeleteLegacyLobsterMenu2951 {

    private static final String MASTER_HOST = getenv("DB_HOST", "cq-cdb-8fjmemkb.sql.tencentcdb.com");
    private static final int MASTER_PORT = Integer.parseInt(getenv("DB_PORT", "27220"));
    private static final String MASTER_USER = getenv("DB_USER", "root");
    private static final String MASTER_PASSWORD = getenv("DB_PASSWORD", "Ylrz_1q2w3e4r5t6y");
    private static final String MASTER_DB = getenv("DB_NAME", "ylrz_saas");
    private static final long LEGACY_ROOT = 2951L;

    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");
        boolean dryRun = args.length > 0 && "dry-run".equalsIgnoreCase(args[0]);
        System.out.println("=== Delete legacy lobster menu tree (2951) from tenant sys_menu ===");
        System.out.println("dryRun=" + dryRun);

        List<Long> tenantIds;
        try (Connection master = open(MASTER_HOST, MASTER_PORT, MASTER_DB, MASTER_USER, MASTER_PASSWORD)) {
            tenantIds = loadActiveTenantIds(master);
        }

        int ok = 0;
        int skip = 0;
        int fail = 0;
        for (Long tenantId : tenantIds) {
            TenantDb tenant;
            try (Connection master = open(MASTER_HOST, MASTER_PORT, MASTER_DB, MASTER_USER, MASTER_PASSWORD)) {
                tenant = loadTenant(master, tenantId);
            }
            if (tenant == null) {
                skip++;
                continue;
            }
            System.out.println("\n[TENANT " + tenantId + "] " + tenant.database);
            try (Connection conn = open(tenant.host, tenant.port, tenant.database, tenant.user, tenant.password)) {
                if (!tableExists(conn, "sys_menu")) {
                    System.out.println("  [SKIP] no sys_menu");
                    skip++;
                    continue;
                }
                if (!menuExists(conn, LEGACY_ROOT)) {
                    System.out.println("  [SKIP] menu 2951 not found");
                    skip++;
                    continue;
                }
                Set<Long> ids = collectSubtree(conn, LEGACY_ROOT);
                System.out.println("  subtree size=" + ids.size() + " ids=" + ids);
                if (dryRun) {
                    ok++;
                    continue;
                }
                deleteRoleMenuRefs(conn, ids);
                int deleted = deleteMenus(conn, ids);
                printRoots(conn);
                System.out.println("  [OK] deleted sys_menu rows=" + deleted);
                ok++;
            } catch (Exception e) {
                System.out.println("  [ERR] " + e.getMessage());
                fail++;
            }
        }

        System.out.println("\n=== SUMMARY ===");
        System.out.println("OK=" + ok + " SKIP=" + skip + " FAIL=" + fail);
        if (fail > 0) {
            System.exit(1);
        }
    }

    private static Set<Long> collectSubtree(Connection conn, long rootId) throws SQLException {
        Set<Long> all = new LinkedHashSet<>();
        collectChildren(conn, rootId, all);
        all.add(rootId);
        return all;
    }

    private static void collectChildren(Connection conn, long parentId, Set<Long> acc) throws SQLException {
        String sql = "SELECT menu_id FROM sys_menu WHERE parent_id = ?";
        try (PreparedStatement ps = conn.prepareStatement(sql)) {
            ps.setLong(1, parentId);
            try (ResultSet rs = ps.executeQuery()) {
                while (rs.next()) {
                    long id = rs.getLong(1);
                    if (acc.add(id)) {
                        collectChildren(conn, id, acc);
                    }
                }
            }
        }
    }

    private static void deleteRoleMenuRefs(Connection conn, Set<Long> menuIds) throws SQLException {
        if (!tableExists(conn, "sys_role_menu") || menuIds.isEmpty()) {
            return;
        }
        String in = placeholders(menuIds.size());
        String sql = "DELETE FROM sys_role_menu WHERE menu_id IN (" + in + ")";
        try (PreparedStatement ps = conn.prepareStatement(sql)) {
            bindIds(ps, menuIds);
            int n = ps.executeUpdate();
            if (n > 0) {
                System.out.println("  deleted sys_role_menu rows=" + n);
            }
        }
    }

    private static int deleteMenus(Connection conn, Set<Long> menuIds) throws SQLException {
        List<Long> ordered = new ArrayList<>(menuIds);
        Collections.sort(ordered, Collections.reverseOrder());
        int total = 0;
        String sql = "DELETE FROM sys_menu WHERE menu_id = ?";
        try (PreparedStatement ps = conn.prepareStatement(sql)) {
            for (Long id : ordered) {
                ps.setLong(1, id);
                total += ps.executeUpdate();
            }
        }
        return total;
    }

    private static void printRoots(Connection conn) throws SQLException {
        String sql = "SELECT menu_id, menu_name, path, visible FROM sys_menu "
                + "WHERE parent_id = 0 AND (menu_id = 29900 OR path LIKE '%lobster%') ORDER BY menu_id";
        try (Statement st = conn.createStatement(); ResultSet rs = st.executeQuery(sql)) {
            while (rs.next()) {
                System.out.printf("  remaining root id=%d path=%s visible=%s name=%s%n",
                        rs.getLong(1), rs.getString(3), rs.getString(4), rs.getString(2));
            }
        }
    }

    private static boolean menuExists(Connection conn, long menuId) throws SQLException {
        try (PreparedStatement ps = conn.prepareStatement("SELECT 1 FROM sys_menu WHERE menu_id = ? LIMIT 1")) {
            ps.setLong(1, menuId);
            try (ResultSet rs = ps.executeQuery()) {
                return rs.next();
            }
        }
    }

    private static String placeholders(int n) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < n; i++) {
            if (i > 0) sb.append(',');
            sb.append('?');
        }
        return sb.toString();
    }

    private static void bindIds(PreparedStatement ps, Set<Long> ids) throws SQLException {
        int i = 1;
        for (Long id : ids) {
            ps.setLong(i++, id);
        }
    }

    private static boolean tableExists(Connection conn, String table) throws SQLException {
        try (ResultSet rs = conn.getMetaData().getTables(null, null, table, null)) {
            return rs.next();
        }
    }

    private static List<Long> loadActiveTenantIds(Connection master) throws SQLException {
        List<Long> ids = new ArrayList<>();
        try (Statement st = master.createStatement();
             ResultSet rs = st.executeQuery("SELECT id FROM tenant_info WHERE status = 1 ORDER BY id")) {
            while (rs.next()) {
                ids.add(rs.getLong(1));
            }
        }
        return ids;
    }

    private static TenantDb loadTenant(Connection master, long tenantId) throws SQLException {
        try (PreparedStatement ps = master.prepareStatement(
                "SELECT db_url, db_account, db_pwd FROM tenant_info WHERE id = ? AND status = 1 LIMIT 1")) {
            ps.setLong(1, tenantId);
            try (ResultSet rs = ps.executeQuery()) {
                if (!rs.next()) {
                    return null;
                }
                return parseJdbcUrl(rs.getString("db_url"), rs.getString("db_account"), rs.getString("db_pwd"));
            }
        }
    }

    private static TenantDb parseJdbcUrl(String jdbcUrl, String user, String password) {
        String body = jdbcUrl.substring("jdbc:mysql://".length());
        int slash = body.indexOf('/');
        String hostPort = body.substring(0, slash);
        String rest = body.substring(slash + 1);
        int q = rest.indexOf('?');
        String database = q >= 0 ? rest.substring(0, q) : rest;
        int colon = hostPort.indexOf(':');
        TenantDb t = new TenantDb();
        t.host = colon >= 0 ? hostPort.substring(0, colon) : hostPort;
        t.port = colon >= 0 ? Integer.parseInt(hostPort.substring(colon + 1)) : 3306;
        t.database = database;
        t.user = user != null ? user : MASTER_USER;
        t.password = password != null ? password : MASTER_PASSWORD;
        return t;
    }

    private static Connection open(String host, int port, String database, String user, String password)
            throws SQLException {
        return DriverManager.getConnection(
                "jdbc:mysql://" + host + ":" + port + "/" + database
                        + "?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&allowMultiQueries=true",
                user, password);
    }

    private static String getenv(String key, String defaultValue) {
        String v = System.getenv(key);
        return v != null && !v.isEmpty() ? v : defaultValue;
    }

    private static final class TenantDb {
        String host;
        int port;
        String database;
        String user;
        String password;
    }
}