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

/* Globals for tests */
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: create a SrcList with a single table name */
static SrcList* makeSrcList(const char *zName){
  Token t;
  memset(&t, 0, sizeof(t));
  t.z = zName;
  t.n = (int)strlen(zName);
  return sqlite3SrcListAppend(gDb, 0, &t, 0);
}

/* Helper: initialize a Parse object for our db */
static void initParse(Parse *p){
  memset(p, 0, sizeof(*p));
  p->db = gDb;
}

/* Test: successful copy for an ordinary table */
void test_sqlite3AlterBeginAddColumn_success_creates_partial_copy(void) {
  char *err = 0;
  int rc;

  /* Create a normal table with multiple columns and defaults */
  rc = sqlite3_exec(gDb,
    "CREATE TABLE t(a INTEGER DEFAULT 1, b TEXT, c REAL DEFAULT 3.14);",
    0, 0, &err);
  TEST_ASSERT_EQUAL_INT_MESSAGE(SQLITE_OK, rc, err ? err : "create failed");
  if (err) sqlite3_free(err), err = 0;

  /* Find original table metadata */
  Table *pOrig = sqlite3FindTable(gDb, "t", "main");
  TEST_ASSERT_NOT_NULL(pOrig);
  TEST_ASSERT_TRUE(pOrig->nCol > 0);

  /* Prepare SrcList and Parse */
  SrcList *pSrc = makeSrcList("t");
  TEST_ASSERT_NOT_NULL(pSrc);

  Parse parse;
  initParse(&parse);
  TEST_ASSERT_NULL(parse.pNewTable);

  /* Call the target function while holding btree mutexes */
  sqlite3BtreeEnterAll(gDb);
  sqlite3AlterBeginAddColumn(&parse, pSrc);
  sqlite3BtreeLeaveAll(gDb);

  /* Verify success: no error and pNewTable populated */
  TEST_ASSERT_EQUAL_INT(0, parse.nErr);
  TEST_ASSERT_NOT_NULL(parse.pNewTable);

  Table *pNew = parse.pNewTable;

  /* Name must be prefixed as "sqlite_altertab_t" */
  TEST_ASSERT_NOT_NULL(pNew->zName);
  TEST_ASSERT_EQUAL_STRING("sqlite_altertab_t", pNew->zName);

  /* Column count should match */
  TEST_ASSERT_EQUAL_INT(pOrig->nCol, pNew->nCol);

  /* Column names duplicated and hashes computed */
  for(int i=0; i<pNew->nCol; i++){
    Column *cOrig = &pOrig->aCol[i];
    Column *cNew  = &pNew->aCol[i];
    TEST_ASSERT_NOT_NULL(cNew->zCnName);
    TEST_ASSERT_NOT_NULL(cOrig->zCnName);
    /* Ensure duplicated pointer (not aliasing original) and same content */
    TEST_ASSERT(cNew->zCnName != cOrig->zCnName);
    TEST_ASSERT_EQUAL_STRING(cOrig->zCnName, cNew->zCnName);
    /* Ensure hash is set to case-insensitive hash of the name */
    TEST_ASSERT_EQUAL_INT(sqlite3StrIHash(cNew->zCnName), cNew->hName);
  }

  /* Schema and addColOffset should match original */
  TEST_ASSERT(pNew->pSchema == pOrig->pSchema);
  TEST_ASSERT_TRUE(pNew->u.tab.addColOffset > 0);
  TEST_ASSERT_EQUAL_INT(pOrig->u.tab.addColOffset, pNew->u.tab.addColOffset);

  /* Default expression list should be duplicated if present on original */
  if( pOrig->u.tab.pDfltList ){
    TEST_ASSERT_NOT_NULL(pNew->u.tab.pDfltList);
    TEST_ASSERT_NOT_NULL(pOrig->u.tab.pDfltList);
    TEST_ASSERT(pNew->u.tab.pDfltList != pOrig->u.tab.pDfltList);
    TEST_ASSERT_EQUAL_INT(pOrig->u.tab.pDfltList->nExpr,
                          pNew->u.tab.pDfltList->nExpr);
  }

  /* New table refcount should be 1 */
  TEST_ASSERT_EQUAL_INT(1, pNew->nTabRef);

  /* Cleanup: delete the allocated table copy */
  sqlite3DeleteTable(gDb, pNew);
  parse.pNewTable = 0;
}

/* Test: attempting to alter a view should raise an error */
void test_sqlite3AlterBeginAddColumn_on_view_sets_error(void) {
  char *err = 0;
  int rc;

  rc = sqlite3_exec(gDb, "CREATE VIEW v AS SELECT 1 AS x;", 0, 0, &err);
  TEST_ASSERT_EQUAL_INT_MESSAGE(SQLITE_OK, rc, err ? err : "create view failed");
  if (err) sqlite3_free(err), err = 0;

  SrcList *pSrc = makeSrcList("v");
  TEST_ASSERT_NOT_NULL(pSrc);

  Parse parse;
  initParse(&parse);

  sqlite3BtreeEnterAll(gDb);
  sqlite3AlterBeginAddColumn(&parse, pSrc);
  sqlite3BtreeLeaveAll(gDb);

  TEST_ASSERT_TRUE(parse.nErr > 0);
  TEST_ASSERT_NULL(parse.pNewTable);
  TEST_ASSERT_NOT_NULL(parse.zErrMsg);
  TEST_ASSERT_NOT_NULL(strstr(parse.zErrMsg, "Cannot add a column to a view"));

  sqlite3DbFree(gDb, parse.zErrMsg);
  parse.zErrMsg = 0;
}

/* Test: attempting to alter a system table (sqlite_sequence) should raise an error */
void test_sqlite3AlterBeginAddColumn_on_system_table_sets_error(void) {
  char *err = 0;
  int rc;

  /* Create an AUTOINCREMENT table to ensure sqlite_sequence exists */
  rc = sqlite3_exec(gDb,
    "CREATE TABLE at(id INTEGER PRIMARY KEY AUTOINCREMENT, b TEXT);",
    0, 0, &err);
  TEST_ASSERT_EQUAL_INT_MESSAGE(SQLITE_OK, rc, err ? err : "create autoinc failed");
  if (err) sqlite3_free(err), err = 0;

  /* Ensure sqlite_sequence exists by inserting a row (usually created at table create, but this is safe) */
  rc = sqlite3_exec(gDb, "INSERT INTO at(b) VALUES('x');", 0, 0, &err);
  TEST_ASSERT_EQUAL_INT_MESSAGE(SQLITE_OK, rc, err ? err : "insert failed");
  if (err) sqlite3_free(err), err = 0;

  /* Now attempt to alter sqlite_sequence */
  SrcList *pSrc = makeSrcList("sqlite_sequence");
  TEST_ASSERT_NOT_NULL(pSrc);

  Parse parse;
  initParse(&parse);

  sqlite3BtreeEnterAll(gDb);
  sqlite3AlterBeginAddColumn(&parse, pSrc);
  sqlite3BtreeLeaveAll(gDb);

  TEST_ASSERT_TRUE(parse.nErr > 0);
  TEST_ASSERT_NULL(parse.pNewTable);
  TEST_ASSERT_NOT_NULL(parse.zErrMsg);
  TEST_ASSERT_NOT_NULL(strstr(parse.zErrMsg, "table sqlite_sequence may not be altered"));

  sqlite3DbFree(gDb, parse.zErrMsg);
  parse.zErrMsg = 0;
}

/* Test: table not found should set an error and no pNewTable */
void test_sqlite3AlterBeginAddColumn_table_not_found_sets_error(void) {
  SrcList *pSrc = makeSrcList("no_such_table_123");
  TEST_ASSERT_NOT_NULL(pSrc);

  Parse parse;
  initParse(&parse);

  sqlite3BtreeEnterAll(gDb);
  sqlite3AlterBeginAddColumn(&parse, pSrc);
  sqlite3BtreeLeaveAll(gDb);

  TEST_ASSERT_TRUE(parse.nErr > 0);
  TEST_ASSERT_NULL(parse.pNewTable);
  TEST_ASSERT_NOT_NULL(parse.zErrMsg);
  TEST_ASSERT_NOT_NULL(strstr(parse.zErrMsg, "no such table"));

  sqlite3DbFree(gDb, parse.zErrMsg);
  parse.zErrMsg = 0;
}

/* Main runner */
int main(void) {
  UNITY_BEGIN();
  RUN_TEST(test_sqlite3AlterBeginAddColumn_success_creates_partial_copy);
  RUN_TEST(test_sqlite3AlterBeginAddColumn_on_view_sets_error);
  RUN_TEST(test_sqlite3AlterBeginAddColumn_on_system_table_sets_error);
  RUN_TEST(test_sqlite3AlterBeginAddColumn_table_not_found_sets_error);
  return UNITY_END();
}