#coding:utf-8

"""
ID:          issue-7388
ISSUE:       7388
TITLE:       Different invariants optimization between views and CTEs
DESCRIPTION:
    We run two queries as described in the ticket (see variables 'query1' and 'query2').
    For each of them we gather table statistics (sequential and indexed reads) and explained plan.
    If any value in the pair (seq, idx) differ between two statistics then we print all info about that plus explained plans.
    Otherwise we can consider test passed (without printing any concrete data from statistics or explained plans).
NOTES:
    [20.01.2024] pzotov
    Confirmed problem on 5.0.0.871.
    Checked on 6.0.0.218, 5.0.1.1318.
"""

import pytest
from pathlib import Path
from firebird.qa import *

init_sql = """
    create view v1
    as select r.rdb$relation_id as id, r.rdb$relation_name as name
    from rdb$relations r
    inner join rdb$relation_fields rf on r.rdb$relation_name = rf.rdb$relation_name
    left join rdb$security_classes sc on r.rdb$security_class = sc.rdb$security_class
    ;
    commit;
"""
db = db_factory(init = init_sql)

act = python_act('db')

SUCCESS_MSG = "Expected: table statistics are identical."


#----------------------------------------------------------

def replace_leading(source, char="#"):
    stripped = source.lstrip()
    return char * (len(source) - len(stripped)) + stripped

#----------------------------------------------------------

@pytest.mark.version('>=5.0')
def test_1(act: Action, capsys):
    t_map = { 'rdb$relation_fields' : -1, 'rdb$relations' : -1, 'rdb$security_classes' : -1 }

    query1 = """
        select 1
        from v1
        where id = (select max(id) from v1)
    """

    query2 = """
        with sub as (
        select r.rdb$relation_id as id, r.rdb$relation_name as name
        from rdb$relations r
          inner join rdb$relation_fields rf on r.rdb$relation_name = rf.rdb$relation_name
          left join rdb$security_classes sc on r.rdb$security_class = sc.rdb$security_class
        )
        select * from sub
        where sub.id = (select max(id) from sub)
    """
    q_map = {query1 : '', query2 : ''}
    
    with act.db.connect() as con:
        cur = con.cursor()
        for k in t_map.keys():
            cur.execute(f"select rdb$relation_id from rdb$relations where rdb$relation_name = upper('{k}')")
            test_rel_id = None
            for r in cur:
                test_rel_id = r[0]
            assert test_rel_id, f"Could not find ID for relation '{k}'. Check its name!"
            t_map[ k ] = test_rel_id

        result_map = {}

        for qry_txt in q_map.keys():
            with cur.prepare(qry_txt) as ps:
                q_map[qry_txt] = ps.detailed_plan
                for tab_nm,tab_id in t_map.items():
                    tabstat1 = [ p for p in con.info.get_table_access_stats() if p.table_id == tab_id ]
                    cur.execute(qry_txt)
                    for r in cur:
                        pass
                    tabstat2 = [ p for p in con.info.get_table_access_stats() if p.table_id == tab_id ]

                    result_map[qry_txt, tab_nm] = \
                        (
                           tabstat2[0].sequential if tabstat2[0].sequential else 0
                          ,tabstat2[0].indexed if tabstat2[0].indexed else 0
                        )
                    if tabstat1:
                        seq, idx = result_map[qry_txt, tab_nm]
                        seq -= (tabstat1[0].sequential if tabstat1[0].sequential else 0)
                        idx -= (tabstat1[0].indexed if tabstat1[0].indexed else 0)
                        result_map[qry_txt, tab_nm] = (seq, idx)

        '''
        print('q_map.items():')
        for k,v in q_map.items():
            print('k=',k)
            print('v=',v)
            print('')

        print('')
        print('result_map.items():')
        for k,v in result_map.items():
            print('(query,tab_nm)=',k)
            print('v=',v)
            print('')
        '''

        mism_found = 0
        for tab_nm in t_map.keys():
            if result_map[query1, tab_nm] == result_map[query2, tab_nm]:
                pass
            else:
                print(f"Mismatch detected in the statistics for table '{tab_nm}'.")
                print('Query-1:')
                print('(seq,idx) =',result_map[query1, tab_nm])
                print('Query-2:')
                print('(seq,idx) =',result_map[query2, tab_nm])
                mism_found += 1

        if mism_found:
            print('Check execution plans:')
            for i,qry_txt in enumerate(q_map.keys()):
                print('-' * 22)
                print(f'Query-{i+1}:')
                print(qry_txt)
                print('-' * 22)
                print('Plan:')
                print( '\n'.join([replace_leading(s) for s in q_map[qry_txt].split('\n')]) ) # explained plan, with preserving indents by replacing leading spaces with '#'
                print('')
        else:
            print(SUCCESS_MSG)


    act.expected_stdout = SUCCESS_MSG
    act.stdout = capsys.readouterr().out
    assert act.clean_stdout == act.clean_expected_stdout