MODULE SQLiteIntrospection;
(* Statement metadata and library diagnostics:
   sql, expanded_sql, readonly, busy, next_stmt, stmt_status,
   version/sourceid, error_offset, autocommit, complete and limits. *)

FROM SYSTEM IMPORT ADDRESS;
FROM CStr IMPORT CString, Copy;
FROM SQLite IMPORT
  SQLiteOk, SQLiteRow, SQLiteDone,
  SQLiteOpenReadWrite, SQLiteOpenCreate, SQLiteOpenMemory,
  SQLiteLimitLikePatternLength, SQLiteStmtStatusVmStep,
  sqlite3_open_v2, sqlite3_exec, sqlite3_close_v2,
  sqlite3_prepare_v2, sqlite3_step, sqlite3_finalize,
  sqlite3_bind_int, sqlite3_sql, sqlite3_expanded_sql,
  sqlite3_stmt_readonly, sqlite3_stmt_busy, sqlite3_next_stmt,
  sqlite3_stmt_status, sqlite3_libversion,
  sqlite3_libversion_number, sqlite3_sourceid, sqlite3_threadsafe,
  sqlite3_error_offset, sqlite3_get_autocommit, sqlite3_complete,
  sqlite3_limit, sqlite3_free;

VAR
  ExitCode : INTEGER;
  db, stmt, s1, s2, p, q : ADDRESS;
  rc : INTEGER;
  ok : BOOLEAN;

PROCEDURE SameText (a, b : ARRAY OF CHAR) : BOOLEAN;
VAR
  i : INTEGER;
BEGIN
  i := 0;
  WHILE (a[i] # CHR(0)) AND (a[i] = b[i]) DO
    i := i + 1
  END;
  RETURN (a[i] = CHR(0)) AND (b[i] = CHR(0))
END SameText;

PROCEDURE TextIs (s : CString; want : ARRAY OF CHAR) : BOOLEAN;
VAR
  buf : ARRAY [0..127] OF CHAR;
BEGIN
  IF s = NIL THEN RETURN FALSE END;
  IF Copy(s, buf) = 0 THEN RETURN FALSE END;
  RETURN SameText(buf, want)
END TextIs;

PROCEDURE TextNonEmpty (s : CString) : BOOLEAN;
VAR
  buf : ARRAY [0..127] OF CHAR;
BEGIN
  IF s = NIL THEN RETURN FALSE END;
  RETURN Copy(s, buf) > 0
END TextNonEmpty;

PROCEDURE ExecSQL (sql : ARRAY OF CHAR) : BOOLEAN;
VAR
  errmsg : ADDRESS;
  good : BOOLEAN;
BEGIN
  errmsg := NIL;
  good := sqlite3_exec(db, sql, NIL, NIL, errmsg) = SQLiteOk;
  IF errmsg # NIL THEN
    sqlite3_free(errmsg)
  END;
  RETURN good
END ExecSQL;

PROCEDURE Finish (VAR s : ADDRESS) : BOOLEAN;
VAR
  good : BOOLEAN;
BEGIN
  good := TRUE;
  IF s # NIL THEN
    IF sqlite3_finalize(s) # SQLiteOk THEN good := FALSE END;
    s := NIL
  END;
  RETURN good
END Finish;

BEGIN
  ExitCode := 1;
  db := NIL; stmt := NIL; s1 := NIL; s2 := NIL;
  p := NIL; q := NIL; ok := FALSE;

  IF (sqlite3_open_v2(":memory:", db,
        SQLiteOpenReadWrite + SQLiteOpenCreate + SQLiteOpenMemory,
        NIL) = SQLiteOk) AND (db # NIL) THEN
    ok := (sqlite3_libversion_number() > 0)
          AND TextNonEmpty(sqlite3_libversion())
          AND TextNonEmpty(sqlite3_sourceid())
          AND (sqlite3_threadsafe() > 0);

    IF ok THEN
      ok := (sqlite3_complete("SELECT 1;") = 1)
            AND (sqlite3_complete("SELECT 1") = 0)
    END;

    IF ok THEN
      ok := (sqlite3_get_autocommit(db) = 1)
            AND ExecSQL("BEGIN;")
            AND (sqlite3_get_autocommit(db) = 0)
            AND ExecSQL("COMMIT;")
            AND (sqlite3_get_autocommit(db) = 1)
    END;

    IF ok THEN
      rc := sqlite3_limit(db, SQLiteLimitLikePatternLength, -1);
      ok := (rc > 0)
            AND (sqlite3_limit(db, SQLiteLimitLikePatternLength, 1000) = rc)
            AND (sqlite3_limit(db, SQLiteLimitLikePatternLength, -1) = 1000)
            AND (sqlite3_limit(db, SQLiteLimitLikePatternLength, rc) = 1000)
    END;

    IF ok THEN ok := ExecSQL("CREATE TABLE t(x INTEGER);") END;

    (* Original SQL, expanded SQL, readonly/busy and VM counters. *)
    IF ok THEN
      stmt := NIL;
      rc := sqlite3_prepare_v2(db, "SELECT ?;", -1, stmt, NIL);
      ok := (rc = SQLiteOk) AND (stmt # NIL)
            AND (sqlite3_stmt_readonly(stmt) = 1)
            AND TextIs(sqlite3_sql(stmt), "SELECT ?;")
            AND (sqlite3_stmt_busy(stmt) = 0);
      IF ok THEN
        ok := sqlite3_bind_int(stmt, 1, 42) = SQLiteOk
      END;
      IF ok THEN
        p := sqlite3_expanded_sql(stmt);
        ok := (p # NIL) AND TextIs(p, "SELECT 42;");
        IF p # NIL THEN
          sqlite3_free(p);
          p := NIL
        END
      END;
      IF ok THEN ok := sqlite3_step(stmt) = SQLiteRow END;
      IF ok THEN ok := sqlite3_stmt_busy(stmt) = 1 END;
      IF ok THEN
        ok := sqlite3_stmt_status(stmt, SQLiteStmtStatusVmStep, 0) > 0
      END;
      IF ok THEN ok := sqlite3_step(stmt) = SQLiteDone END;
      IF ok THEN ok := sqlite3_stmt_busy(stmt) = 0 END;
      IF ok THEN
        ok := (sqlite3_stmt_status(stmt, SQLiteStmtStatusVmStep, 1) > 0)
              AND (sqlite3_stmt_status(stmt, SQLiteStmtStatusVmStep, 0) = 0)
      END;
      IF NOT Finish(stmt) THEN ok := FALSE END
    END;

    (* A write statement is not readonly. *)
    IF ok THEN
      stmt := NIL;
      rc := sqlite3_prepare_v2(db, "INSERT INTO t(x) VALUES(1);",
                               -1, stmt, NIL);
      ok := (rc = SQLiteOk) AND (stmt # NIL)
            AND (sqlite3_stmt_readonly(stmt) = 0);
      IF NOT Finish(stmt) THEN ok := FALSE END
    END;

    (* Syntax errors expose a byte offset. *)
    IF ok THEN
      stmt := NIL;
      rc := sqlite3_prepare_v2(db, "SELECT * FROM;", -1, stmt, NIL);
      ok := (rc # SQLiteOk) AND (stmt = NIL)
            AND (sqlite3_error_offset(db) >= 0);
      IF NOT Finish(stmt) THEN ok := FALSE END
    END;

    (* Statement iteration: exactly the two prepared statements. *)
    IF ok THEN
      rc := sqlite3_prepare_v2(db, "SELECT 1;", -1, s1, NIL);
      ok := (rc = SQLiteOk) AND (s1 # NIL);
      IF ok THEN
        rc := sqlite3_prepare_v2(db, "SELECT 2;", -1, s2, NIL);
        ok := (rc = SQLiteOk) AND (s2 # NIL)
      END;
      IF ok THEN
        p := sqlite3_next_stmt(db, NIL);
        q := sqlite3_next_stmt(db, p);
        ok := (p # NIL) AND (q # NIL) AND (p # q)
              AND (sqlite3_next_stmt(db, q) = NIL)
      END;
      IF NOT Finish(s1) THEN ok := FALSE END;
      IF NOT Finish(s2) THEN ok := FALSE END
    END
  END;

  IF NOT Finish(stmt) THEN ok := FALSE END;
  IF NOT Finish(s1) THEN ok := FALSE END;
  IF NOT Finish(s2) THEN ok := FALSE END;
  IF db # NIL THEN
    IF sqlite3_close_v2(db) # SQLiteOk THEN ok := FALSE END
  END;
  IF ok THEN ExitCode := 42 END
END SQLiteIntrospection.