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

/* Wrapper for the static function provided by the build harness */
extern void test_errorMPrintf(sqlite3_context *pCtx, const char *zFmt, ...);

/* Unity fixtures */
void setUp(void) {
  /* no-op */
}
void tearDown(void) {
  /* no-op */
}

/* Helpers to register UDFs that invoke test_errorMPrintf */

static void xErr_basic(sqlite3_context *ctx, int argc, sqlite3_value **argv){
  /* Expect 4 args: text, int, int64, double */
  const char *name = (const char*)sqlite3_value_text(argv[0]);
  int a = sqlite3_value_int(argv[1]);
  sqlite3_int64 b = sqlite3_value_int64(argv[2]);
  double c = sqlite3_value_double(argv[3]);
  test_errorMPrintf(ctx, "Name:%s Int:%d I64:%lld Dbl:%.2f", name, a, b, c);
}

static void xErr_percent(sqlite3_context *ctx, int argc, sqlite3_value **argv){
  /* No args needed. Just a percent literal test. */
  (void)argc; (void)argv;
  test_errorMPrintf(ctx, "Rate: %d%%", 100);
}

static void xErr_null(sqlite3_context *ctx, int argc, sqlite3_value **argv){
  /* 1 arg: possibly NULL text */
  const char *s = (const char*)sqlite3_value_text(argv[0]); /* may be NULL */
  test_errorMPrintf(ctx, "S=%s", s);
}

static void xErr_long(sqlite3_context *ctx, int argc, sqlite3_value **argv){
  /* 1 arg: long text string */
  const char *s = (const char*)sqlite3_value_text(argv[0]);
  test_errorMPrintf(ctx, "Long:%s", s);
}

/* Utility: prepare, step and capture error message on failure.
   Returns a heap-allocated copy of sqlite3_errmsg(db) when step returns SQLITE_ERROR.
   Caller must sqlite3_free on the returned string (allocated with sqlite3_malloc). */
static char* step_and_capture_errmsg(sqlite3 *db, sqlite3_stmt *stmt, int *pRc){
  int rc = sqlite3_step(stmt);
  if( pRc ) *pRc = rc;
  if( rc==SQLITE_ERROR ){
    const char *z = sqlite3_errmsg(db);
    size_t n = strlen(z);
    char *copy = (char*)sqlite3_malloc((int)n+1);
    if( copy ){
      memcpy(copy, z, n+1);
    }
    return copy;
  }
  return NULL;
}

/* Test 1: Basic formatting with multiple specifiers */
void test_errorMPrintf_formats_basic(void){
  sqlite3 *db = 0;
  sqlite3_stmt *stmt = 0;
  int rc;

  rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_create_function_v2(db, "t_basic", 4, SQLITE_UTF8, NULL,
                                  xErr_basic, NULL, NULL, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  const char *sql = "SELECT t_basic('Alice', 42, 1234567890123, 3.14159)";
  rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  int stepRc = SQLITE_OK;
  char *errmsg = step_and_capture_errmsg(db, stmt, &stepRc);
  TEST_ASSERT_EQUAL_INT(SQLITE_ERROR, stepRc);

  /* Expect rounding to two decimals for %.2f */
  const char *expected = "Name:Alice Int:42 I64:1234567890123 Dbl:3.14";
  TEST_ASSERT_NOT_NULL(errmsg);
  TEST_ASSERT_EQUAL_STRING(expected, errmsg);

  sqlite3_free(errmsg);
  sqlite3_finalize(stmt);
  sqlite3_close(db);
}

/* Test 2: Literal percent "%%" */
void test_errorMPrintf_handles_percent_literal(void){
  sqlite3 *db = 0;
  sqlite3_stmt *stmt = 0;
  int rc;

  rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_create_function_v2(db, "t_pct", 0, SQLITE_UTF8, NULL,
                                  xErr_percent, NULL, NULL, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  const char *sql = "SELECT t_pct()";
  rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  int stepRc = SQLITE_OK;
  char *errmsg = step_and_capture_errmsg(db, stmt, &stepRc);
  TEST_ASSERT_EQUAL_INT(SQLITE_ERROR, stepRc);

  const char *expected = "Rate: 100%";
  TEST_ASSERT_NOT_NULL(errmsg);
  TEST_ASSERT_EQUAL_STRING(expected, errmsg);

  sqlite3_free(errmsg);
  sqlite3_finalize(stmt);
  sqlite3_close(db);
}

/* Test 3: NULL string is rendered as "(NULL)" by sqlite3_mprintf family */
void test_errorMPrintf_null_string_becomes_NULL_literal(void){
  sqlite3 *db = 0;
  sqlite3_stmt *stmt = 0;
  int rc;

  rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_create_function_v2(db, "t_null", 1, SQLITE_UTF8, NULL,
                                  xErr_null, NULL, NULL, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  const char *sql = "SELECT t_null(NULL)";
  rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  int stepRc = SQLITE_OK;
  char *errmsg = step_and_capture_errmsg(db, stmt, &stepRc);
  TEST_ASSERT_EQUAL_INT(SQLITE_ERROR, stepRc);

  const char *expected = "S=(NULL)";
  TEST_ASSERT_NOT_NULL(errmsg);
  TEST_ASSERT_EQUAL_STRING(expected, errmsg);

  sqlite3_free(errmsg);
  sqlite3_finalize(stmt);
  sqlite3_close(db);
}

/* Test 4: Very long message to exercise allocation and correctness */
void test_errorMPrintf_long_message(void){
  sqlite3 *db = 0;
  sqlite3_stmt *stmt = 0;
  int rc;

  /* Build a long input string */
  const int N = 50000;
  char *longInput = (char*)malloc((size_t)N + 1);
  TEST_ASSERT_NOT_NULL(longInput);
  memset(longInput, 'A', (size_t)N);
  longInput[N] = '\0';

  /* Expected: "Long:" + longInput */
  size_t prefixLen = 5; /* "Long:" */
  char *expected = (char*)malloc(prefixLen + (size_t)N + 1);
  TEST_ASSERT_NOT_NULL(expected);
  memcpy(expected, "Long:", prefixLen);
  memcpy(expected + prefixLen, longInput, (size_t)N + 1);

  rc = sqlite3_open(":memory:", &db);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_create_function_v2(db, "t_long", 1, SQLITE_UTF8, NULL,
                                  xErr_long, NULL, NULL, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_prepare_v2(db, "SELECT t_long(?)", -1, &stmt, NULL);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  rc = sqlite3_bind_text(stmt, 1, longInput, -1, SQLITE_TRANSIENT);
  TEST_ASSERT_EQUAL_INT(SQLITE_OK, rc);

  int stepRc = SQLITE_OK;
  char *errmsg = step_and_capture_errmsg(db, stmt, &stepRc);
  TEST_ASSERT_EQUAL_INT(SQLITE_ERROR, stepRc);

  TEST_ASSERT_NOT_NULL(errmsg);
  TEST_ASSERT_EQUAL_STRING(expected, errmsg);

  sqlite3_free(errmsg);
  sqlite3_finalize(stmt);
  sqlite3_close(db);

  free(expected);
  free(longInput);
}

int main(void) {
  UNITY_BEGIN();
  RUN_TEST(test_errorMPrintf_formats_basic);
  RUN_TEST(test_errorMPrintf_handles_percent_literal);
  RUN_TEST(test_errorMPrintf_null_string_becomes_NULL_literal);
  RUN_TEST(test_errorMPrintf_long_message);
  return UNITY_END();
}