#!/bin/bash

##################################################
# EVN                                            #
# - SERVER_ID                                    #
# - GROUP_REPLICATION                            #
# - GROUP_REPLICATION_LOCAL_ADDRESS              #
# - GROUP_REPLICATION_GROUP_SEEDS                #
# - EXTRA_SCRIPTS                                #
# Mount file                                     #
# - /etc/my.cnf                                  #
# Mount dir                                      #
# - LOG_DIR                                      #
# - DATA_DIR                                     #
# - BINLOG_DIR                                   #
##################################################

set -euo pipefail
export LANG=en_US.UTF-8
trap Quit EXIT

PIDS=
GOT_SIGTERM=
LOG_DIR='/var/log/mysql'
DATA_DIR='/var/lib/mysql'
BINLOG_DIR='/var/lib/mysql-bin'
SOCK_FILE='/run/mysqld/mysqld.sock'
PID_FILE='/run/mysqld/mysqld.pid'
INIT_FLAG=
GROUP_REPLICATION="${GROUP_REPLICATION:+1}"
EXTRA_SCRIPTS="${EXTRA_SCRIPTS:+1}"

if [ -n "$GROUP_REPLICATION" ]; then
    SERVER_ID=${SERVER_ID:?}
    GROUP_REPILCATION_GROUP_NAME="${GROUP_REPILCATION_GROUP_NAME:-aaaabbbb-7777-8888-9999-ccccddddeeee}"
    GROUP_REPLICATION_LOCAL_ADDRESS="${GROUP_REPLICATION_LOCAL_ADDRESS}"
    GROUP_REPLICATION_GROUP_SEEDS="${GROUP_REPLICATION_GROUP_SEEDS}"
    BOOTSTRAP_GROUP=1
fi

function Print {
    local file=/dev/null
    [ '-f' = "$1" ] && file=$2 && shift && shift
    date +"[%F %T] $*" | tee -a $file
}

function Quit {
    Print killing mysqld ...
    mysqladmin shutdown || true
    while :; do
        pkill -f mysqld && Print killing mysqld ... || break
        sleep 1
    done
    Print Container stopped.
    test -n "$GOT_SIGTERM"
}

function ProbeSeeds {
    local all_seeds=" ${GROUP_REPLICATION_GROUP_SEEDS//,/ } "
    local other_seeds="${all_seeds/ $GROUP_REPLICATION_LOCAL_ADDRESS / }"
    local seed= seed_return=0
    [ "$all_seeds" = "$other_seeds" ] \
        && Print Not found local_address in group_seeds! \
        && exit 1
    Print Probing connection to other seeds ...
    for seed in $other_seeds; do
        echo -n "Connecting $seed ... "
        curl -s --connect-timeout 8 ftp://$seed || seed_return=$?
        [ 6 = "$seed_return" ] && echo failed to resolve host:"${seed%:*}"! && exit 1
        [ 7 = "$seed_return" ] && echo offline. && continue
        echo online.
        BOOTSTRAP_GROUP=
        break
    done
}

function Init {
    rm -f ${SOCK_FILE}* ${PID_FILE}
    chown -R mysql:mysql $LOG_DIR $BINLOG_DIR $DATA_DIR
    if [ ! -d "$DATA_DIR/mysql" ]; then
        Print Writing essential server config to /etc/mysql/my.cnf ...
        Print Initing mysql db files ...
        mysqld_pre_systemd
        INIT_FLAG=1
    fi
}

function InitGroupReplication {
    if ! grep -i '^group[-_]replication' /etc/my.cnf; then
        Print Writing advisable group replication config to /etc/my.cnf ...
        grep -i '^binlog[-_]expire[-_]logs[-_]seconds' /etc/my.cnf \
            || echo 'binlog-expire-logs-seconds = 172800' >> /etc/my.cnf
        echo 'group-replication-consistency = BEFORE_ON_PRIMARY_FAILOVER
group-replication-member-expel-timeout = 2
group-replication-unreachable-majority-timeout = 2
group-replication-autorejoin-tries = 0
group-replication-exit-state-action = OFFLINE_MODE
' >> /etc/my.cnf
    fi
    if ! grep -i '^group[-_]replication' /etc/mysql/my.cnf; then
        Print Writing essential group replication config to /etc/mysql/my.cnf ...
        cat >> /etc/mysql/my.cnf <<-EOF
server-id = $SERVER_ID
gtid-mode = ON
enforce-gtid-consistency = TRUE
binlog-format = ROW
binlog-checksum = NONE
log-bin = /var/lib/mysql-bin/master
relay-log = /var/lib/mysql-bin/slave
log-slave-updates = TRUE
relay-log-recovery = TRUE
slave-parallel-type = LOGICAL_CLOCK
slave-preserve-commit-order = ON
disabled-storage-engines = "MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"
plugin-load-add = "group_replication.so;mysql_clone.so"
group-replication-group-name = "$GROUP_REPILCATION_GROUP_NAME"
group-replication-local-address = "$GROUP_REPLICATION_LOCAL_ADDRESS"
group-replication-group-seeds = "$GROUP_REPLICATION_GROUP_SEEDS"
group-replication-bootstrap-group = OFF
group-replication-start-on-boot = OFF
EOF
    fi
}

function ImportInitSql {
    local sql_file= sql_files=
    mysql -e "CREATE USER docker@localhost IDENTIFIED BY 'China_19\$(10)!'"
    mysql -e "GRANT SHUTDOWN ON *.* TO docker@localhost"
    if sql_files="$(ls $LOG_DIR/init_sql/*.sql 2>/dev/null)"; then
        Print Importing the sql files ...
        for sql_file in $sql_files; do
             Print Importing $sql_file ...
             mysql < $sql_file
        done
        Print Imported all sql files successfully.
    fi
}

function StartGroupReplication {
    if [ -n "$BOOTSTRAP_GROUP" ]; then
        Print Bootstraping new group replication ...
        mysql -e "
            SET GLOBAL group_replication_bootstrap_group=ON;
            START GROUP_REPLICATION;
            SET GLOBAL group_replication_bootstrap_group=OFF;
        "
    else
        Print Joining a running group replication ...
        mysql -e "START GROUP_REPLICATION;"
    fi
}

function CreateGroupReplicationChannel {
    Print Creating user and channel of group replication ...
    mysql -e "SET SQL_LOG_BIN=0;
        CREATE USER rpl@'%' IDENTIFIED BY 'Rpl_1234';
        GRANT REPLICATION SLAVE ON *.* TO rpl@'%';
        GRANT BACKUP_ADMIN ON *.* TO rpl@'%';
        FLUSH PRIVILEGES;
        SET SQL_LOG_BIN=1;
        CHANGE MASTER TO 
            MASTER_USER='rpl', 
            MASTER_PASSWORD='Rpl_1234' 
            FOR CHANNEL 'group_replication_recovery';
    "
}

function StartExtraScripts {
    Print Starting extra scripts ...
    while sleep 2; do
        for script in $(find $LOG_DIR/extra_scripts/ -type f -executable \
            2>/dev/null || true); do
            $script &
        done
    done &
}

function StartProc {
    Print Starting mysql ...
    mysqld -u mysql &
    PIDS="$PIDS $!"
    while sleep 1; do
        [ -e $SOCK_FILE ] && break || echo -n .
        [ ! -e /proc/$! ] && echo && Print unexpected error! && exit
    done
    echo
    if [ -n "$INIT_FLAG" ]; then
        ImportInitSql
        if [ -n "$GROUP_REPLICATION" ]; then
            CreateGroupReplicationChannel
        fi
    fi
    if [ -n "$GROUP_REPLICATION" ]; then
        StartGroupReplication
    fi
    if [ -n "$EXTRA_SCRIPTS" ]; then
        StartExtraScripts
    fi
    Print MySQL is ready for connections.
}

function Main {
    local pid=
    [ -n "$GROUP_REPLICATION" ] && ProbeSeeds
    Init
    [ -n "$GROUP_REPLICATION" ] && InitGroupReplication
    StartProc
    trap "GOT_SIGTERM=1; Print Got SIGTERM ..." SIGTERM
    while [ -z "$GOT_SIGTERM" ] && sleep 1; do
        for pid in $PIDS; do
            [ ! -e /proc/$pid ] && Print Unexpected error! && exit
        done
    done
}

# Start here
Main