#coding:utf-8
#
# id:           bugs.core_4618
# title:        Rollback doesn`t undo changes when MERGE statement updates the same target rows multiple times and PLAN MERGE is used
# decription:   
#                   Checked (again, 07.06.2020) on 3.0.6.33296.
#               
#                   07.06.2020. NOTE: separate section for FB 4.x was added since fix for core-2274 issued:
#                   MERGE can not change the same record multiple times.
#                   For this reason we have to check only presense of ERROR in 4.x and that result is the same after merge and rollback.
#                   Checked on 4.0.0.2022
#                
# tracker_id:   CORE-4618
# min_versions: ['3.0']
# versions:     3.0, 4.0
# qmid:         None

import pytest
from firebird.qa import db_factory, isql_act, Action

# version: 3.0
# resources: None

substitutions_1 = [('=.*', '')]

init_script_1 = """"""

db_1 = db_factory(page_size=4096, sql_dialect=3, init=init_script_1)

test_script_1 = """
    set term ^;
    execute block as begin
      begin execute statement 'create sequence g'; when any do begin end end
    end
    ^ set term ;^
    commit;
    alter sequence g restart with 0;
    commit;
    recreate table t(id int, x int, y int);
    commit;
    insert into t(id) select gen_id(g,1) from rdb$types rows 3;
    update t set x=mod(id,2), y=mod(id,3);
    commit;
    
    select 'before_merge' msg, t.* from t;
    
    --set plan on;
    merge into t
    using t s
    on t.x=s.x
    when matched then update set t.x = t.x+s.y, t.y = t.y - s.x;
    set plan off;
    
    select 'after_merge' msg, t.* from t;
    
    rollback;
    
    select 'after_rollback' msg, t.* from t; 

    -- ::: NB ::: Seems that trouble was NOT only because of PLAN MERGE.
    -- Compare with WI-T3.0.0.31374 Firebird 3.0 Beta 1 - here HASH also is used!
    --    MSG                    ID            X            Y 
    --    ============ ============ ============ ============ 
    --    before_merge            1            1            1 
    --    before_merge            2            0            2 
    --    before_merge            3            1            0 
    --    
    --    PLAN HASH (T NATURAL, S NATURAL)
    --    
    --    MSG                   ID            X            Y 
    --    =========== ============ ============ ============ 
    --    after_merge            1            2           -1 
    --    after_merge            2            2            2 
    --    after_merge            3            2           -2 
    --    
    --    MSG                      ID            X            Y 
    --    ============== ============ ============ ============ 
    --    after_rollback            1            2         -255 
    --    after_rollback            2            0            2 
    --    after_rollback            3            2            0 
"""

act_1 = isql_act('db_1', test_script_1, substitutions=substitutions_1)

expected_stdout_1 = """
    MSG                    ID            X            Y 
    ============ ============ ============ ============ 
    before_merge            1            1            1 
    before_merge            2            0            2 
    before_merge            3            1            0 
    
    MSG                   ID            X            Y
    =========== ============ ============ ============ 
    after_merge            1            2            0 
    after_merge            2            2            2 
    after_merge            3            2           -1 
    
    MSG                      ID            X            Y 
    ============== ============ ============ ============ 
    after_rollback            1            1            1 
    after_rollback            2            0            2 
    after_rollback            3            1            0 
"""

@pytest.mark.version('>=3.0,<4.0')
def test_1(act_1: Action):
    act_1.expected_stdout = expected_stdout_1
    act_1.execute()
    assert act_1.clean_stdout == act_1.clean_expected_stdout

# version: 4.0
# resources: None

substitutions_2 = [('[ \t]+', ' '), ('=', '')]

init_script_2 = """"""

db_2 = db_factory(sql_dialect=3, init=init_script_2)

test_script_2 = """
    recreate table test(id int, x int, y int);
    create descending index test_x_dec on test(x);
    commit;
    insert into test(id, x, y) values(1, 1, 1);
    insert into test(id, x, y) values(2, 0, 2);
    insert into test(id, x, y) values(3, 1, 0);
    commit;
    
    select 'before_merge' msg, t.* from test t;
    
    merge into test t
    using test s on t.x=s.x
    when matched then update set t.x = t.x+s.y, t.y = t.y - s.x;
    
    select 'after_merge' msg, t.* from test t;
    rollback;
    select 'after_rollback' msg, t.* from test t; 
"""

act_2 = isql_act('db_2', test_script_2, substitutions=substitutions_2)

expected_stdout_2 = """
    MSG                    ID            X            Y 
    ============ ============ ============ ============ 
    before_merge            1            1            1 
    before_merge            2            0            2 
    before_merge            3            1            0 


    MSG                   ID            X            Y 
    =========== ============ ============ ============ 
    after_merge            1            1            1 
    after_merge            2            0            2 
    after_merge            3            1            0 


    MSG                      ID            X            Y 
    ============== ============ ============ ============ 
    after_rollback            1            1            1 
    after_rollback            2            0            2 
    after_rollback            3            1            0 

"""
expected_stderr_2 = """
    Statement failed, SQLSTATE = 21000
    Multiple source records cannot match the same target during MERGE
"""

@pytest.mark.version('>=4.0')
def test_2(act_2: Action):
    act_2.expected_stdout = expected_stdout_2
    act_2.expected_stderr = expected_stderr_2
    act_2.execute()
    assert act_2.clean_stderr == act_2.clean_expected_stderr
    assert act_2.clean_stdout == act_2.clean_expected_stdout