#include "sqliteInt.h"
#include "unity.h"
#include <stdlib.h>
#include <string.h>

extern void test_renameWalkWith(Walker *pWalker, Select *pSelect);

static sqlite3 *gDb = NULL;

/* Unity setup/teardown */
void setUp(void) {
  int rc = sqlite3_open(":memory:", &gDb);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);
  TEST_ASSERT_NOT_NULL(gDb);
}
void tearDown(void) {
  if (gDb) {
    sqlite3_close(gDb);
    gDb = NULL;
  }
}

/* Helper: allocate a minimal Select with given selFlags */
static Select *allocSelect(u32 selFlags){
  Select *p = (Select*)sqlite3DbMallocZero(gDb, sizeof(Select));
  TEST_ASSERT_NOT_NULL_MESSAGE(p, "allocSelect failed");
  p->selFlags = selFlags;
  return p;
}

/* Helper: allocate a With object with nCte entries and the provided Selects */
static With *allocWith(int nCte, Select **apSel){
  /* With uses a flexible array member a[1] */
  int nByte = (int)(sizeof(With) + (nCte-1) * sizeof(p->a[0]));
  With *p = (With*)sqlite3DbMallocZero(gDb, nByte);
  TEST_ASSERT_NOT_NULL_MESSAGE(p, "allocWith failed");
  p->nCte = nCte;
  p->pOuter = 0;
  for(int i=0; i<nCte; i++){
    p->a[i].pSelect = apSel ? apSel[i] : 0;
    p->a[i].pCols = 0;     /* keep NULL to avoid rename mapping side-effects */
    p->a[i].zName = 0;     /* not needed for these tests */
    p->a[i].zCteErr = 0;
  }
  return p;
}

/* Walker select callback that increments a counter in walker.u.p */
static int countSelectCb(Walker *pWalker, Select *pSel){
  (void)pSel;
  int *pCnt = (int*)pWalker->u.p;
  if( pCnt ) (*pCnt)++;
  return WRC_Continue;
}

/* Test 1: When pSelect->pWith is NULL, nothing happens */
void test_renameWalkWith_no_with_clause(void){
  Parse sParse;
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = gDb;

  /* Create a dummy outer WITH to ensure pParse->pWith is not touched */
  With *pOuter = allocWith(1, NULL);
  sParse.pWith = pOuter;

  /* Minimal top-level SELECT with no WITH clause */
  Select *pTop = allocSelect(SF_Expanded); /* flags irrelevant here */
  pTop->pWith = NULL;

  int count = 0;
  Walker w;
  memset(&w, 0, sizeof(w));
  w.pParse = &sParse;
  w.xSelectCallback = countSelectCb;
  w.u.p = &count;

  test_renameWalkWith(&w, pTop);

  TEST_ASSERT_EQUAL_INT(0, count);           /* no CTEs walked */
  TEST_ASSERT_EQUAL_PTR(pOuter, sParse.pWith); /* unchanged */
}

/* Test 2: WITH present with SF_Expanded set: walks each CTE; no stack push/pop */
void test_renameWalkWith_expanded_with_multiple_ctes(void){
  Parse sParse;
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = gDb;

  With *pOuter = allocWith(1, NULL);
  sParse.pWith = pOuter;

  /* Create two simple CTE selects with SF_Expanded set */
  Select *pCTE1 = allocSelect(SF_Expanded);
  Select *pCTE2 = allocSelect(SF_Expanded);
  Select *apCTE[2] = { pCTE1, pCTE2 };

  With *pWith = allocWith(2, apCTE);

  /* Top-level select that carries the WITH clause */
  Select *pTop = allocSelect(0);
  pTop->pWith = pWith;

  int count = 0;
  Walker w;
  memset(&w, 0, sizeof(w));
  w.pParse = &sParse;
  w.xSelectCallback = countSelectCb;
  w.u.p = &count;

  test_renameWalkWith(&w, pTop);

  TEST_ASSERT_EQUAL_INT(2, count);            /* walked both CTEs */
  TEST_ASSERT_EQUAL_PTR(pOuter, sParse.pWith); /* no push/pop -> unchanged */
}

/* Test 3: WITH present with SF_Expanded not set: pushes/pops with-stack and walks each CTE */
void test_renameWalkWith_push_and_pop_with_stack(void){
  Parse sParse;
  memset(&sParse, 0, sizeof(sParse));
  sParse.db = gDb;

  With *pOuter = allocWith(1, NULL);
  sParse.pWith = pOuter;

  /* Create three simple CTE selects with SF_Expanded unset to force push/dup */
  Select *pCTE1 = allocSelect(0);
  Select *pCTE2 = allocSelect(0);
  Select *pCTE3 = allocSelect(0);
  Select *apCTE[3] = { pCTE1, pCTE2, pCTE3 };

  With *pWith = allocWith(3, apCTE);

  /* Top-level select that carries the WITH clause */
  Select *pTop = allocSelect(0);
  pTop->pWith = pWith;

  int count = 0;
  Walker w;
  memset(&w, 0, sizeof(w));
  w.pParse = &sParse;
  w.xSelectCallback = countSelectCb;
  w.u.p = &count;

  test_renameWalkWith(&w, pTop);

  TEST_ASSERT_EQUAL_INT(3, count);             /* walked all CTEs */
  TEST_ASSERT_EQUAL_PTR(pOuter, sParse.pWith);  /* stack restored after pop */
}

int main(void){
  UNITY_BEGIN();
  RUN_TEST(test_renameWalkWith_no_with_clause);
  RUN_TEST(test_renameWalkWith_expanded_with_multiple_ctes);
  RUN_TEST(test_renameWalkWith_push_and_pop_with_stack);
  return UNITY_END();
}