#!/usr/bin/env python
#
# Public Domain 2014-present MongoDB, Inc.
# Public Domain 2008-2014 WiredTiger, Inc.
#
# This is free and unencumbered software released into the public domain.
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# of this software dedicate any and all copyright interest in the
# software to the public domain. We make this dedication for the benefit
# of the public at large and to the detriment of our heirs and
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# software under copyright law.
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import fnmatch, os, shutil, threading, time
from wtthread import checkpoint_thread, op_thread
from helper import simulate_crash_restart
import wiredtiger, wttest
from wtdataset import SimpleDataSet
from wtscenario import make_scenarios
from wiredtiger import stat

# test_checkpoint_snapshot03.py
#   This test is to check RTS skips the unnecessary pages when the table has more than the
#   checkpoint snapshot.
class test_checkpoint_snapshot03(wttest.WiredTigerTestCase):

    # Create a table.
    uri = "table:test_checkpoint_snapshot03"
    nrows = 500000

    def conn_config(self):
        config = 'cache_size=250MB,statistics=(all),statistics_log=(json,on_close,wait=1),log=(enabled=true)'
        return config

    def large_updates(self, uri, value, ds, nrows):
        # Update a large number of records.
        session = self.session
        cursor = session.open_cursor(uri)
        for i in range(0, nrows):
            session.begin_transaction()
            cursor[ds.key(i)] = value
            session.commit_transaction()
        cursor.close()

    def check(self, check_value, uri, nrows):
        session = self.session
        session.begin_transaction()
        cursor = session.open_cursor(uri)
        count = 0
        for k, v in cursor:
            self.assertEqual(v, check_value)
            count += 1
        session.commit_transaction()
        self.assertEqual(count, nrows)

    def test_checkpoint_snapshot(self):

        ds = SimpleDataSet(self, self.uri, 0, key_format="S", value_format="S",config='log=(enabled=false),leaf_page_max=4k')
        ds.populate()
        valuea = "aaaaa" * 100
        valueb = "bbbbb" * 100
        valuec = "ccccc" * 100

        session1 = self.conn.open_session()
        session1.begin_transaction()
        cursor1 = session1.open_cursor(self.uri)
        for i in range(self.nrows, self.nrows + 1):
            cursor1.set_key(ds.key(i))
            cursor1.set_value(valueb)
            self.assertEqual(cursor1.insert(), 0)

        self.large_updates(self.uri, valuea, ds, self.nrows)
        self.check(valuea, self.uri, self.nrows)

        self.session.checkpoint()
        session1.rollback_transaction()
        self.reopen_conn()

        # Check the table contains the last checkpointed value.
        self.check(valuea, self.uri, self.nrows)

        session1 = self.conn.open_session()
        session1.begin_transaction()
        cursor1 = session1.open_cursor(self.uri)
        for i in range(self.nrows, self.nrows + 1):
            cursor1.set_key(ds.key(i))
            cursor1.set_value(valueb)
            self.assertEqual(cursor1.insert(), 0)

        self.session.begin_transaction()
        cursor = self.session.open_cursor(self.uri)
        for i in range(0, 1):
            cursor.set_key(ds.key(i))
            cursor.set_value(valuec)
            self.assertEqual(cursor.update(), 0)
        self.session.commit_transaction()

        self.session.checkpoint()
        session1.rollback_transaction()

        # Simulate a server crash and restart.
        simulate_crash_restart(self, ".", "RESTART")

        stat_cursor = self.session.open_cursor('statistics:', None, None)
        inconsistent_ckpt = stat_cursor[stat.conn.txn_rts_inconsistent_ckpt][2]
        keys_removed = stat_cursor[stat.conn.txn_rts_keys_removed][2]
        keys_restored = stat_cursor[stat.conn.txn_rts_keys_restored][2]
        pages_skipped = stat_cursor[stat.conn.txn_rts_tree_walk_skip_pages][2]
        upd_aborted = stat_cursor[stat.conn.txn_rts_upd_aborted][2]
        stat_cursor.close()

        self.assertGreater(inconsistent_ckpt, 0)
        self.assertEqual(upd_aborted, 0)
        self.assertGreaterEqual(keys_removed, 0)
        self.assertEqual(keys_restored, 0)
        self.assertGreater(pages_skipped, 0)

if __name__ == '__main__':
    wttest.run()