import java.util.*;

/**
 * Unit test for yabause CWE-312 defect yabause-0001.
 *
 * yabause-0001: In yabause/src/netlink.c, NetlinkWriteByte() handles the
 * Saturn NetLink modem dial-up login sequence.  When NETLINK_DEBUG is
 * compiled in, two NETLINK_LOG calls write the Saturn internet credentials
 * verbatim into the debug log:
 *
 *   Line 582: NETLINK_LOG("login response: %s", inbuffer+inbufferstart)
 *   Line 592: NETLINK_LOG("password response: %s", inbuffer+inbufferstart)
 *
 * This test models the C logging logic and verifies the redaction fix.
 */
public class YabauseNetlinkCredentialLogTest {

    /** Connection state machine, mirroring NL_CONNECTSTATUS_* enum. */
    enum ConnectStatus {
        IDLE, LOGIN1, LOGIN2, LOGIN3, CONNECTED
    }

    /** Simulates the NETLINK_LOG debug output sink. */
    static class NetlinkLog {
        private final List<String> entries = new ArrayList<>();

        void log(String msg) {
            entries.add(msg);
        }

        boolean anyEntryContains(String substring) {
            for (String e : entries) {
                if (e.contains(substring)) return true;
            }
            return false;
        }

        List<String> getEntries() {
            return Collections.unmodifiableList(entries);
        }
    }

    // ---------------------------------------------------------------
    // DEFECTIVE: logs login name and password verbatim
    // ---------------------------------------------------------------

    static ConnectStatus defectiveHandleCarriageReturn(
            NetlinkLog log, ConnectStatus status, String inbuffer) {

        if (status == ConnectStatus.LOGIN1) {
            // Line 582 — logs login name verbatim
            log.log(String.format("login response: %s", inbuffer));
            return ConnectStatus.LOGIN2;
        }
        if (status == ConnectStatus.LOGIN2) {
            // Line 592 — logs password verbatim
            log.log(String.format("password response: %s", inbuffer));
            return ConnectStatus.LOGIN3;
        }
        if (status == ConnectStatus.LOGIN3) {
            log.log(String.format("shell response: %s", inbuffer));
            return ConnectStatus.CONNECTED;
        }
        return status;
    }

    // ---------------------------------------------------------------
    // FIXED: redacts credentials, logs byte count only
    // ---------------------------------------------------------------

    static ConnectStatus fixedHandleCarriageReturn(
            NetlinkLog log, ConnectStatus status, String inbuffer) {

        if (status == ConnectStatus.LOGIN1) {
            // Patched line 582: redacted
            log.log(String.format("login response: [REDACTED %d bytes]",
                inbuffer.length()));
            return ConnectStatus.LOGIN2;
        }
        if (status == ConnectStatus.LOGIN2) {
            // Patched line 592: redacted
            log.log(String.format("password response: [REDACTED %d bytes]",
                inbuffer.length()));
            return ConnectStatus.LOGIN3;
        }
        if (status == ConnectStatus.LOGIN3) {
            log.log(String.format("shell response: %s", inbuffer));
            return ConnectStatus.CONNECTED;
        }
        return status;
    }

    // ---------------------------------------------------------------
    // Test cases
    // ---------------------------------------------------------------

    static class TestCase {
        final String loginName;
        final String password;

        TestCase(String loginName, String password) {
            this.loginName = loginName;
            this.password  = password;
        }
    }

    static final TestCase[] CASES = {
        new TestCase("saturn_user",    "hunter2"),
        new TestCase("netlink_player", "S3cr3tP@ss"),
        new TestCase("segaNet001",     "CorrectHorseBattery"),
    };

    public static void main(String[] args) {
        int pass = 0;
        int fail = 0;

        for (TestCase tc : CASES) {
            // --- DEFECTIVE path ---
            NetlinkLog defLog = new NetlinkLog();
            ConnectStatus s   = ConnectStatus.LOGIN1;

            s = defectiveHandleCarriageReturn(defLog, s, tc.loginName);
            s = defectiveHandleCarriageReturn(defLog, s, tc.password);
            defectiveHandleCarriageReturn(defLog, s, "$ ");

            boolean defExpLogin = defLog.anyEntryContains(tc.loginName);
            boolean defExpPass  = defLog.anyEntryContains(tc.password);

            if (defExpLogin) {
                System.out.println("PASS (defect confirmed): login name '"
                    + tc.loginName + "' appears in defective log");
                pass++;
            } else {
                System.out.println("FAIL (defect NOT confirmed): login name '"
                    + tc.loginName + "' missing from defective log");
                fail++;
            }

            if (defExpPass) {
                System.out.println("PASS (defect confirmed): password '"
                    + tc.password + "' appears in defective log");
                pass++;
            } else {
                System.out.println("FAIL (defect NOT confirmed): password '"
                    + tc.password + "' missing from defective log");
                fail++;
            }

            // --- FIXED path ---
            NetlinkLog fixLog = new NetlinkLog();
            s = ConnectStatus.LOGIN1;

            s = fixedHandleCarriageReturn(fixLog, s, tc.loginName);
            s = fixedHandleCarriageReturn(fixLog, s, tc.password);
            fixedHandleCarriageReturn(fixLog, s, "$ ");

            boolean fixExpLogin = fixLog.anyEntryContains(tc.loginName);
            boolean fixExpPass  = fixLog.anyEntryContains(tc.password);

            if (!fixExpLogin) {
                System.out.println("PASS (fix confirmed): login name '"
                    + tc.loginName + "' NOT in fixed log");
                pass++;
            } else {
                System.out.println("FAIL (fix broken): login name '"
                    + tc.loginName + "' still appears in fixed log");
                fail++;
            }

            if (!fixExpPass) {
                System.out.println("PASS (fix confirmed): password '"
                    + tc.password + "' NOT in fixed log");
                pass++;
            } else {
                System.out.println("FAIL (fix broken): password '"
                    + tc.password + "' still appears in fixed log");
                fail++;
            }

            // Redaction markers must be present
            boolean hasLoginRedact = fixLog.anyEntryContains("login response: [REDACTED");
            boolean hasPassRedact  = fixLog.anyEntryContains("password response: [REDACTED");

            if (hasLoginRedact) {
                System.out.println("PASS (login redaction marker present)");
                pass++;
            } else {
                System.out.println("FAIL (login redaction marker missing)");
                fail++;
            }

            if (hasPassRedact) {
                System.out.println("PASS (password redaction marker present)");
                pass++;
            } else {
                System.out.println("FAIL (password redaction marker missing)");
                fail++;
            }

            // Shell response (non-credential) must still log verbatim
            boolean shellVisible = fixLog.anyEntryContains("shell response: $ ");
            if (shellVisible) {
                System.out.println("PASS (non-credential shell response visible)");
                pass++;
            } else {
                System.out.println("FAIL (non-credential shell response missing)");
                fail++;
            }
        }

        System.out.println();
        System.out.println("Results: " + pass + " passed, " + fail + " failed");
        if (fail > 0) {
            System.exit(1);
        }
    }
}