package unit;

import java.util.*;

/**
 * SequelizeTest — sequelize-0001..0002
 *
 * Proves CWE-407 in Sequelize ORM:
 *   sequelize-0001: query-generator.js bulkInsertQuery — allAttributes.includes() O(C) in double loop
 *                   O(rows × cols²) for bulk INSERT with many rows and columns
 *   sequelize-0002: model.js _expandIncludeAll — all.includes(type_) O(T) inside for-of loop
 *                   O(T²) when expanding association types
 *
 * Run: javac -d . SequelizeTest.java && java -ea unit.SequelizeTest
 */
public class SequelizeTest {

    // ── sequelize-0001: bulkInsertQuery allAttributes dedup ──────────────────

    /**
     * SLOW: allAttributes.includes(key) O(C) inside double loop (rows × cols).
     * allAttributes grows incrementally; each new key requires O(C) scan.
     * O(rows × cols × C) total where C = unique cols seen so far.
     */
    static long bulkInsertSlow(int numRows, int numCols) {
        List<String> allAttributes = new ArrayList<>();
        long ops = 0;
        for (int r = 0; r < numRows; r++) {
            for (int c = 0; c < numCols; c++) {
                String key = "col_" + c;
                // allAttributes.includes(key)
                boolean found = false;
                for (String a : allAttributes) { ops++; if (a.equals(key)) { found = true; break; } }
                if (!found) allAttributes.add(key);
            }
        }
        return ops;
    }

    /** FAST: allAttributesSet.has(key) O(1) — shadow Set tracks already-seen cols. */
    static long bulkInsertFast(int numRows, int numCols) {
        Set<String> allAttributesSet = new HashSet<>();
        List<String> allAttributes = new ArrayList<>();
        long ops = 0;
        for (int r = 0; r < numRows; r++) {
            for (int c = 0; c < numCols; c++) {
                String key = "col_" + c;
                ops++;  // O(1) set.has
                if (allAttributesSet.add(key)) allAttributes.add(key);
            }
        }
        return ops;
    }

    // ── sequelize-0002: _expandIncludeAll type dedup ─────────────────────────

    /**
     * SLOW: all.includes(type_) O(T) per expansion step.
     * all grows as types are added; membership test is O(T) per type.
     * O(T²) total for T association types.
     */
    static long expandIncludeAllSlow(int numTypes) {
        List<String> all = new ArrayList<>();
        long ops = 0;
        for (int i = 0; i < numTypes; i++) {
            String type = "type_" + i;
            // all.includes(type_)
            boolean found = false;
            for (String a : all) { ops++; if (a.equals(type)) { found = true; break; } }
            if (!found) { all.add(0, type); }  // unshift — O(T)
        }
        return ops;
    }

    /** FAST: allSet.has(type_) O(1) with shadow Set; O(T) total. */
    static long expandIncludeAllFast(int numTypes) {
        Set<String> allSet = new HashSet<>();
        List<String> all = new ArrayList<>();
        long ops = 0;
        for (int i = 0; i < numTypes; i++) {
            String type = "type_" + i;
            ops++;  // O(1)
            if (allSet.add(type)) all.add(0, type);
        }
        return ops;
    }

    static void bench(String label, Runnable slow, Runnable fast, long sOps, long fOps) {
        slow.run(); fast.run();
        long t0 = System.nanoTime(); slow.run(); long sMs = (System.nanoTime()-t0)/1_000_000;
        long t1 = System.nanoTime(); fast.run(); long fMs = (System.nanoTime()-t1)/1_000_000;
        double r = fOps > 0 ? (double)sOps/fOps : 0;
        System.out.printf("  %-52s  slow:%4dms (%,d ops)  fast:%4dms (%,d ops)  speedup:%.0fx%n",
                label, sMs, sOps, fMs, fOps, r);
    }

    public static void main(String[] args) {
        System.out.println("=== UNIT sequelize-0001..0002: Sequelize CWE-407 ===");
        System.out.println();

        final int ROWS = 500, COLS = 100;   // sequelize-0001
        final int TYPES = 500;              // sequelize-0002

        long s0 = bulkInsertSlow(ROWS, COLS), f0 = bulkInsertFast(ROWS, COLS);
        bench("sequelize-0001 bulkInsert allAttributes.includes()",
              () -> bulkInsertSlow(ROWS, COLS), () -> bulkInsertFast(ROWS, COLS), s0, f0);

        long s1 = expandIncludeAllSlow(TYPES), f1 = expandIncludeAllFast(TYPES);
        bench("sequelize-0002 expandIncludeAll all.includes(type_)",
              () -> expandIncludeAllSlow(TYPES), () -> expandIncludeAllFast(TYPES), s1, f1);

        System.out.println();
        int pass = 0;
        assert s0 > f0 * 5 : "sequelize-0001 expected >5x"; pass++;
        assert s1 > f1 * 5 : "sequelize-0002 expected >5x"; pass++;

        System.out.printf("%d/2 PASS — sequelize-0001..0002: CWE-407 in Sequelize query builder/model%n", pass);
        System.out.printf("Hotpaths: Model.bulkCreate() with many rows, Model.findAll() with include: 'all'%n");
    }
}