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

/* Unity setup/teardown */
void setUp(void) {
  /* empty */
}
void tearDown(void) {
  /* empty */
}

/* Helper: initialize a Parse object */
static void initParse(Parse *pParse, sqlite3 *db, const char *zCons){
  memset(pParse, 0, sizeof(*pParse));
  pParse->db = db;
  if( zCons ){
    /* sLastToken.z should point to the end of constraint text buffer */
    pParse->sLastToken.z = zCons + strlen(zCons);
    pParse->sLastToken.n = 0; /* not used by sqlite3AlterSetNotNull */
  }
}

/* Helper: create a SrcList for zDb.zTab (zDb may be NULL for "main") */
static SrcList* makeSrcList(sqlite3 *db, const char *zDb, const char *zTab){
  SrcList *p = 0;
  Token tTab, tDb;
  tTab.z = zTab;
  tTab.n = (int)strlen(zTab);
  if( zDb ){
    tDb.z = zDb;
    tDb.n = (int)strlen(zDb);
    p = sqlite3SrcListAppend(db, 0, &tTab, &tDb);
  }else{
    p = sqlite3SrcListAppend(db, 0, &tTab, 0);
  }
  return p;
}

/* Helper: free error message in Parse */
static void freeParseError(sqlite3 *db, Parse *pParse){
  if( pParse->zErrMsg ){
    sqlite3DbFree(db, pParse->zErrMsg);
    pParse->zErrMsg = 0;
  }
}

/* Test: table does not exist */
static void test_sqlite3AlterSetNotNull_table_not_found(void){
  sqlite3 *db = 0;
  int rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  /* Prepare Parse and inputs */
  const char *zCons = "NOT NULL  -- trailing comment";
  Parse sParse;
  initParse(&sParse, db, zCons);

  SrcList *pSrc = makeSrcList(db, 0, "nosuchtable");
  TEST_ASSERT_NOT_NULL(pSrc);
  Token colTok;
  colTok.z = "a";
  colTok.n = 1;
  Token firstTok;
  firstTok.z = zCons;
  firstTok.n = 3; /* "NOT" */

  /* Call target */
  sqlite3AlterSetNotNull(&sParse, pSrc, &colTok, &firstTok);

  /* Validate: error reported, and no vdbe created */
  TEST_ASSERT_TRUE(sParse.nErr > 0);
  TEST_ASSERT_NOT_NULL(sParse.zErrMsg);
  TEST_ASSERT_NULL(sParse.pVdbe);

  /* Cleanup */
  freeParseError(db, &sParse);
  sqlite3SrcListDelete(db, pSrc);
  sqlite3_close(db);
}

/* Test: table exists, column does not */
static void test_sqlite3AlterSetNotNull_column_not_found(void){
  sqlite3 *db = 0;
  int rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_exec(db, "CREATE TABLE t(a, b);", 0, 0, 0);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  const char *zCons = "NOT NULL  -- trim me";
  Parse sParse;
  initParse(&sParse, db, zCons);

  SrcList *pSrc = makeSrcList(db, 0, "t");
  TEST_ASSERT_NOT_NULL(pSrc);
  Token colTok;
  colTok.z = "c"; /* non-existent column */
  colTok.n = 1;
  Token firstTok;
  firstTok.z = zCons;
  firstTok.n = 3;

  sqlite3AlterSetNotNull(&sParse, pSrc, &colTok, &firstTok);

  /* Expect an error: "no such column" and no VDBE */
  TEST_ASSERT_TRUE(sParse.nErr > 0);
  TEST_ASSERT_NOT_NULL(sParse.zErrMsg);
  if( sParse.zErrMsg ){
    TEST_ASSERT_NOT_NULL(strstr(sParse.zErrMsg, "no such column"));
  }
  TEST_ASSERT_NULL(sParse.pVdbe);

  /* Cleanup */
  freeParseError(db, &sParse);
  sqlite3SrcListDelete(db, pSrc);
  sqlite3_close(db);
}

/* Test: success path - table and column exist, VDBE program is generated */
static void test_sqlite3AlterSetNotNull_success_creates_vdbe_program(void){
  sqlite3 *db = 0;
  int rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_exec(db, "CREATE TABLE t(a, b);", 0, 0, 0);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_exec(db, "INSERT INTO t(a,b) VALUES(1,2),(3,4);", 0, 0, 0);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  const char *zCons = "NOT NULL     -- ensure trimming and comment handling";
  Parse sParse;
  initParse(&sParse, db, zCons);

  SrcList *pSrc = makeSrcList(db, 0, "t");
  TEST_ASSERT_NOT_NULL(pSrc);

  Token colTok;
  colTok.z = "a";
  colTok.n = 1;

  Token firstTok;
  firstTok.z = zCons;
  firstTok.n = 3; /* "NOT" */

  sqlite3AlterSetNotNull(&sParse, pSrc, &colTok, &firstTok);

  /* No parse error expected, and a VDBE should have been created */
  TEST_ASSERT_EQUAL_INT(0, sParse.nErr);
  TEST_ASSERT_NULL(sParse.zErrMsg);
  TEST_ASSERT_NOT_NULL(sParse.pVdbe);

  /* The VDBE should have at least one opcode generated by sqlite3NestedParse */
  if( sParse.pVdbe ){
    int nOp = sqlite3VdbeCurrentAddr(sParse.pVdbe);
    TEST_ASSERT_TRUE(nOp > 0);
  }

  /* Cleanup */
  if( sParse.pVdbe ){
    sqlite3VdbeDelete(sParse.pVdbe);
    sParse.pVdbe = 0;
  }
  sqlite3SrcListDelete(db, pSrc);
  sqlite3_close(db);
}

/* main */
int main(void){
  UNITY_BEGIN();
  RUN_TEST(test_sqlite3AlterSetNotNull_table_not_found);
  RUN_TEST(test_sqlite3AlterSetNotNull_column_not_found);
  RUN_TEST(test_sqlite3AlterSetNotNull_success_creates_vdbe_program);
  return UNITY_END();
}