#coding:utf-8

"""
ID:          issue-6179
ISSUE:       6179
TITLE:       Provide information about Global Commit Number, Commit Number of currently used  database snapshot (if any) and Commit Numbers assigned to the committed transactions
DESCRIPTION:
    From doc\\sql.extensions\\README.builtin_functions.txt about rdb$get_transaction_cn() function:
    ===
    ... numbers returned by RDB$GET_TRANSACTION_CN could have values below:
      -2 - transaction is dead (rolled back)
      -1 - transaction is in limbo
       0 - transaction is active,
       1 - transaction committed before database started or less than OIT
      >1 - transaction committed after database started
      NULL - given transaction number is NULL or greater than database Next Transaction
    ===

    This ISQL-based test does NOT verify cases when tx is dead or in limbo.
    Perhaps, Python-based implementation is required and will be created later.
JIRA:        CORE-5921
FBTEST:      bugs.core_5921
NOTES:
    [05.03.2019]
        renamed RDB$GET_CONTEXT('SYSTEM', 'SNAPSHOT_CN') to RDB$GET_CONTEXT('SYSTEM', 'SNAPSHOT_NUMBER')
        -- see CORE-6016. Checked on 4.0.0.1455
    [09.11.2019]
        added section with substitutions because GET_OIT_CN can differ in SS vs CS: 9 and 10.
    [07.02.2022] pcisar
        Test fails on 4.0.1, because expected output differs:
        real:
          MSG_B For TX > OIT
          GET_TX_B_CN 7
        expected:
          MSG_B For TX < OIT
          GET_TX_B_CN 1
    [22.09.2022] pzotov
        Difference with expected output was caused by auxiliary actions which are performed by qa-plugin
        when test database is created and prepared for work.
        It is necessary to make actions from this test with temporary database about which qa-plugin has no
        any 'knowledge' that it is *database*. Common temporary file can serve for this purpuse.
        After this temp file is declared, one may to use is as *database* by applying SQL script which has
        'CREATE DATABASE <this_temp_file>' statement and furter actions.

    Checked on Linux and Windows: 4.0.1.2692 (SS/CS).
"""
import locale
from pathlib import Path

import pytest
from firebird.qa import *

tmp_fdb = temp_file('tmp_5921.fdb')

db = db_factory()
act = isql_act('db', substitutions = [('[\t ]+', ' ')])

@pytest.mark.version('>=4.0')
def test_1(act: Action, tmp_fdb:Path, capsys):

    init_sql = f"""
        create database 'localhost:{tmp_fdb.absolute()}' user {act.db.user} password '{act.db.password}';
        set list on;
        -- select mon$database_name from mon$database;
        set term ^;
        create or alter procedure sp_set_tx_ctx( a_ctx_var_name varchar(80) ) as
        begin
            rdb$set_context('USER_SESSION', :a_ctx_var_name, current_transaction);
        end
        ^
        set term ;^
        commit;

        set list on;
        execute procedure sp_set_tx_ctx('tx_a');

        select
             iif( tx_a < tx_oit, 'For TX < OIT', iif( tx_a = tx_oit, 'For OIT', 'For TX > OIT') ) as msg_a
            ,rdb$get_transaction_cn( tx_a ) as get_tx_a_cn
        from (
            select
                 d.mon$oldest_transaction as tx_oit
                ,cast( rdb$get_context('USER_SESSION','tx_a') as int ) as tx_a
            from mon$database d
        )
        ;
        rollback;

        execute procedure sp_set_tx_ctx('tx_b');
        commit;

        select
             iif( tx_b < tx_oit, 'For TX < OIT', iif( tx_b = tx_oit, 'For OIT', 'For TX > OIT') ) as msg_b
            ,rdb$get_transaction_cn( tx_b ) as get_tx_b_cn
        from (
            select
                 d.mon$oldest_transaction as tx_oit
                ,cast( rdb$get_context('USER_SESSION','tx_b') as int ) as tx_b
            from mon$database d
        )
        ;

        select
             rdb$get_transaction_cn( d.mon$oldest_transaction ) as get_oit_cn
            ,rdb$get_transaction_cn( current_transaction ) as get_tx_c_cn
            ,rdb$get_transaction_cn( null ) as get_tx_nul_cn
            ,rdb$get_transaction_cn( mon$next_transaction + 1 ) as get_tx_nxx_cn
            -- added 25.09.2018, after commit
            -- https://github.com/FirebirdSQL/firebird/commit/7610a76ff3f263177d0a9f7b02cdc1784a0f3402
            -- all of these columns must contain NULL:
            ,rdb$get_transaction_cn( mon$next_transaction + (9223372036854775807-mon$next_transaction) ) as get_tx_001_cn
            ,rdb$get_transaction_cn( 9223372036854775807 ) as get_tx_002_cn
            ,rdb$get_transaction_cn(-9223372036854775808) as get_tx_003_cn
        from mon$database d;

        set term ^;
        execute block returns( global_cn_sign smallint, snapshot_cn smallint ) as
        begin
           global_cn_sign = sign( rdb$get_context('SYSTEM', 'GLOBAL_CN') );
           snapshot_cn = sign( rdb$get_context('SYSTEM', 'SNAPSHOT_NUMBER') );
           suspend;
        end
        ^
        set term ;^
        commit;
        drop database;
    """
    
    act.expected_stdout = """
        MSG_A                           For TX > OIT
        GET_TX_A_CN                     0
        MSG_B                           For TX < OIT
        GET_TX_B_CN                     1
        GET_OIT_CN                      9
        GET_TX_C_CN                     0
        GET_TX_NUL_CN                   <null>
        GET_TX_NXX_CN                   <null>
        GET_TX_001_CN                   <null>
        GET_TX_002_CN                   <null>
        GET_TX_003_CN                   <null>
        GLOBAL_CN_SIGN                  1
        SNAPSHOT_CN                     1
    """
    act.isql(switches = ['-q'], input = init_sql, connect_db = False, credentials = False, combine_output = True, io_enc = locale.getpreferredencoding())
    assert act.clean_stdout == act.clean_expected_stdout
    act.reset()