#!/bin/bash

function cust_mysql()
{
  local query="${1}"
  "${ti}" "${file}" mysql "${query}" test false false
}

function cmd_ti_tidb_snapshot_read()
{
  ti="${integrated}/ops/ti.sh"
  file="${1}"
  shift 6

  # Init a table with 1 row, record time into t1.
  cust_mysql "drop table if exists test.t"
  cust_mysql "create table if not exists test.t(col_1 int not null, col_2 int not null)"
  cust_mysql "insert into test.t values(1, 101)"
  cust_mysql "alter table test.t set tiflash replica 1"
  "${ti}" "${file}" wait/available test t
  "${ti}" "${file}" sleep 2
  local t1=$(cust_mysql "select now()" | tail -n +2)
  echo "t1: ${t1}"

  # Insert some data after t1, record time into t2.
  "${ti}" "${file}" sleep 2
  cust_mysql "insert into test.t values(1, 102)"
  "${ti}" "${file}" sleep 2
  local t2=$(cust_mysql "select now()" | tail -n +2)
  echo "t2: ${t2}"

  # Snapshot at t1: only old data visible. OK.
  local r1=$(cust_mysql "set @@session.tidb_isolation_read_engines='tiflash'; set @@tidb_snapshot='${t1}'; select max(col_2) from test.t group by col_1" | tail -n +2)
  echo "Result at t1: ${r1}"
  if [ "${r1}" != "101" ]; then
    echo "Result at t1 should be: 101"
    exit 1
  fi

  # Do some compatible DDL after t2, record time into t3.
  "${ti}" "${file}" sleep 2
  cust_mysql "drop table if exists tmp; create table tmp(i int); drop table tmp;"
  "${ti}" "${file}" sleep 2
  local t3=$(cust_mysql "select now()" | tail -n +2)
  echo "t3: ${t3}"

  # Snapshot at t2: new data visible, compatible DDL invisible to TiDB and visible to TiFlash, not blocking query. OK.
  local r2=$(cust_mysql "set @@session.tidb_isolation_read_engines='tiflash'; set @@tidb_snapshot='${t2}'; select max(col_2) from test.t group by col_1" | tail -n +2)
  echo "Result at t2: ${r2}"
  if [ "${r2}" != "102" ]; then
    echo "Result at t2 should be: 102"
    exit 1
  fi

  # Do some incompatible DDL after t3, record time into t4.
  "${ti}" "${file}" sleep 2
  cust_mysql "alter table test.t drop column col_1;"
  "${ti}" "${file}" sleep 2
  local t4=$(cust_mysql "select now()" | tail -n +2)
  echo "t4: ${t4}"

  # Snapshot at t3: new data visible, incompatible DDL invisible to TiDB and visible to TiFlash, blocking query. Error 'newer schema version'.
  local r3=$(cust_mysql "set @@session.tidb_isolation_read_engines='tiflash'; set @@tidb_snapshot='${t3}'; select max(col_2) from test.t group by col_1" 2>&1)
  # local r3=$(cust_mysql "set @@session.tidb_isolation_read_engines='tiflash'; set @@tidb_snapshot='${t3}'; select max(col_2) from test.t group by col_1" 2>&1 | tail -n +2)
  echo "Result at t3: ${r3}"
  # TODO: should be error, and check error match.

  # Snapshot at t3: new data visible, incompatible DDL visible to both TiDB and TiFlash, invalid query. Error 'unknown column'.
  local r4=$(cust_mysql "set @@session.tidb_isolation_read_engines='tiflash'; set @@tidb_snapshot='${t4}'; select max(col_2) from test.t group by col_1" 2>&1)
  echo "Result at t4: ${r4}"
  if [ "${r4}" != "ERROR 1054 (42S22) at line 1: Unknown column 'col_1' in 'group statement'" ]; then
    echo "Result at t4 should be: ERROR 1054 (42S22) at line 1: Unknown column 'col_1' in 'group statement'"
    exit 1
  fi
}

set -euo pipefail
cmd_ti_tidb_snapshot_read "${@}"