#!/bin/bash
#
# t4_dump.sh - mysqldump the TerminalFour database (whole DB, one table, or several tables)
#
# Usage:
#   t4_dump.sh                          Dump the entire terminalfour database
#   t4_dump.sh table1                   Dump a single table
#   t4_dump.sh table1 table2 table3     Dump multiple tables
#   t4_dump.sh -l                       List tables and exit
#
# Options:
#   -o DIR    Output directory (default: current directory)
#   -n NAME   Output filename (default: auto-generated with timestamp)
#   -z        Compress output with gzip
#   -s        Schema only (no data)
#   -l        List tables in the database and exit
#   -h        Show this help
#

set -o pipefail

DB="terminalfour"
OUTDIR="."
OUTNAME=""
COMPRESS=0
SCHEMA_ONLY=0
LIST_ONLY=0

usage() {
    sed -n '3,19p' "$0" | sed 's/^# \{0,1\}//'
    exit "${1:-0}"
}

die() { echo "ERROR: $*" >&2; exit 1; }

# ---------- Parse options ----------
while getopts ":o:n:zslh" opt; do
    case "$opt" in
        o) OUTDIR="$OPTARG" ;;
        n) OUTNAME="$OPTARG" ;;
        z) COMPRESS=1 ;;
        s) SCHEMA_ONLY=1 ;;
        l) LIST_ONLY=1 ;;
        h) usage 0 ;;
        :) die "Option -$OPTARG requires an argument" ;;
        *) die "Unknown option -$OPTARG (use -h for help)" ;;
    esac
done
shift $((OPTIND - 1))
TABLES=("$@")

command -v mysqldump >/dev/null 2>&1 || die "mysqldump not found in PATH"
command -v mysql     >/dev/null 2>&1 || die "mysql client not found in PATH"

# ---------- Locate tomcat conf ----------
path=""
for v in tomcat9 tomcat8 tomcat7; do
    if [[ -e "/usr/share/$v/conf/server.xml" ]]; then
        path="/usr/share/$v/conf"
        break
    fi
done
[[ -n "$path" ]] || die "No tomcat conf dir with server.xml found under /usr/share (tomcat7/8/9)"

SERVER_XML="$path/server.xml"

# ---------- Extract DB credentials ----------
# Pull the attribute value only; take the first match in case of multiple resources.
get_attr() {
    grep -o "$1=\"[^\"]*\"" "$SERVER_XML" | head -n1 | sed -e "s/^$1=\"//" -e 's/"$//'
}

# Decode common XML entities (passwords in server.xml are often escaped)
xml_decode() {
    sed -e 's/&lt;/</g' -e 's/&gt;/>/g' -e 's/&quot;/"/g' -e "s/&apos;/'/g" -e 's/&amp;/\&/g'
}

url="$(get_attr url)"
user="$(get_attr username | xml_decode)"
pass="$(get_attr password | xml_decode)"

# jdbc:mysql://host[:port]/terminalfour?params  ->  host[:port]
hostport="$(echo "$url" | sed -e 's#^jdbc:mysql://##' -e 's#/.*##' | tr -d '[:space:]')"
host="${hostport%%:*}"
port="3306"
[[ "$hostport" == *:* ]] && port="${hostport##*:}"

[[ -n "$host" && -n "$user" ]] || die "Could not parse DB host/user from $SERVER_XML"

# ---------- Write creds to a temporary defaults file ----------
# Keeps the password off the command line (not visible in `ps`) and avoids the
# "Using a password on the command line" warning.
CNF="$(mktemp)" || die "Could not create temp file"
trap 'rm -f "$CNF"' EXIT
chmod 600 "$CNF"
cat > "$CNF" <<EOF
[client]
host=$host
port=$port
user=$user
password="$pass"
EOF

MYSQL=(mysql --defaults-extra-file="$CNF")
DUMP=(mysqldump --defaults-extra-file="$CNF")

# ---------- Connection test ----------
"${MYSQL[@]}" -N -e "SELECT 1" "$DB" >/dev/null 2>&1 \
    || die "Cannot connect to $DB on $host:$port as $user"

# ---------- List mode ----------
if [[ $LIST_ONLY -eq 1 ]]; then
    "${MYSQL[@]}" -N -e "SHOW TABLES" "$DB"
    exit $?
fi

# ---------- Validate requested tables ----------
if [[ ${#TABLES[@]} -gt 0 ]]; then
    existing="$("${MYSQL[@]}" -N -e "SHOW TABLES" "$DB")" || die "Could not list tables"
    missing=()
    for t in "${TABLES[@]}"; do
        grep -qxF "$t" <<< "$existing" || missing+=("$t")
    done
    [[ ${#missing[@]} -eq 0 ]] || die "Table(s) not found in $DB: ${missing[*]}"
fi

# ---------- Build output filename ----------
mkdir -p "$OUTDIR" || die "Could not create output dir $OUTDIR"
ts="$(date +%Y%m%d_%H%M%S)"

if [[ -z "$OUTNAME" ]]; then
    if [[ ${#TABLES[@]} -eq 0 ]]; then
        OUTNAME="${DB}_full_${ts}.sql"
    elif [[ ${#TABLES[@]} -eq 1 ]]; then
        OUTNAME="${DB}_${TABLES[0]}_${ts}.sql"
    else
        OUTNAME="${DB}_${#TABLES[@]}tables_${ts}.sql"
    fi
fi
[[ $COMPRESS -eq 1 && "$OUTNAME" != *.gz ]] && OUTNAME="${OUTNAME}.gz"
OUTFILE="${OUTDIR%/}/$OUTNAME"

# ---------- Dump options ----------
# --single-transaction : consistent snapshot of InnoDB tables without locking
# --quick              : stream rows instead of buffering whole tables in memory
# --no-tablespaces     : skip tablespace info (needs PROCESS privilege, which the
#                        T4 DB user normally doesn't have; T4 doesn't use them)
OPTS=(--single-transaction --quick --no-tablespaces --default-character-set=utf8mb4 --hex-blob)
[[ $SCHEMA_ONLY -eq 1 ]] && OPTS+=(--no-data)
# Include routines/triggers only on a full dump
[[ ${#TABLES[@]} -eq 0 ]] && OPTS+=(--routines --triggers)

# ---------- Run ----------
if [[ ${#TABLES[@]} -eq 0 ]]; then
    echo "Dumping entire '$DB' database from $host:$port ..."
else
    echo "Dumping table(s) from '$DB': ${TABLES[*]} ..."
fi

start=$(date +%s)
if [[ $COMPRESS -eq 1 ]]; then
    "${DUMP[@]}" "${OPTS[@]}" "$DB" "${TABLES[@]}" | gzip > "$OUTFILE"
else
    "${DUMP[@]}" "${OPTS[@]}" "$DB" "${TABLES[@]}" > "$OUTFILE"
fi
rc=$?

if [[ $rc -ne 0 ]]; then
    rm -f "$OUTFILE"
    die "mysqldump failed (exit $rc); partial file removed"
fi

end=$(date +%s)
size="$(du -h "$OUTFILE" | cut -f1)"
echo "Done in $((end - start))s -> $OUTFILE ($size)"