#!/usr/bin/env bash

#grep -e 'Videobridge.createConference\|Conference.expire' jvb.log > 11

### Variables

# log files
LOGFILE="../../jvb.log"
ROTATED_LOGFILE="../../jvb.log.1"
# SQLite database file
DB="../../jitsi-stats.db"

###

# SQLite queries
db_get_state='SELECT filename, filetime, position, inode FROM state WHERE id = 1;'
db_set_state_template="UPDATE state SET time=datetime('now'), filename='%s', filetime='%s', position='%s', inode='%s' WHERE id = 1;"
db_insert_template="INSERT INTO conferences (conference_name, conference_id, start, end) VALUES ('%s', '%s', '%s', '%s');"

# Get the last processed state from the database
get_state() {
    sqlite3 "$DB" "$db_get_state"
}

# Update the state database
set_state() {
    local filename=$1
    local filetime=$2
    local position=${3:-0}
    local inode=$4
    db_set_state=$(printf "$db_set_state_template" "$filename" "$filetime" "$position" "$inode")
    sqlite3 "$DB" "$db_set_state"
}

# Retrieve last log file and position inside it
IFS='|' read -r last_file last_filetime last_pos last_inode <<< $(get_state)

# Initialize logfile vars
last_pos=${last_pos:-0}
current_inode=$(stat -c '%i' "$LOGFILE")
current_filetime=$(stat -c '%Y' "$LOGFILE")

# Local assoc array for conference events tracking
declare -A start_times

jvb_log_parse() {

    local file=$1
    local start_pos=$2
    local new_last_pos="$start_pos"

    # We open the file and start reading from $start_pos bytes
    exec 3<"$file"
    while IFS= read -r line; do
        # save new position (previous plus bytes in current line plus 1 for the new line)
        new_last_pos=$((new_last_pos + ${#line} + 1))

        # locate conference starting event
        if [[ "$line" =~ ([0-9-]+\ [0-9:.]+)\ [A-Z]+:.*\ Videobridge\.createConference#[0-9]+:\ create_conf,\ id=([a-zA-Z0-9]+) ]]; then
            timestamp="${BASH_REMATCH[1]}"
            conferenceId="${BASH_REMATCH[2]}"
            start_times["$conferenceId"]="$timestamp"

        # locate the corresponding conference ending event
        elif [[ "$line" =~ ([0-9-]+\ [0-9:.]+)\ [A-Z]+:.*\[confId=([a-zA-Z0-9]+)\ .*conf_name=([^ ]+)@.*\]\ Conference\.expire ]]; then
            end_time="${BASH_REMATCH[1]}"
            conferenceId="${BASH_REMATCH[2]}"
            conferenceName="${BASH_REMATCH[3]}"
            start_time="${start_times["$conferenceId"]}"

            if [[ -n "$start_time" ]]; then
                db_insert=$(printf "$db_insert_template" "$conferenceName" "$conferenceId" "$start_time" "$end_time")
                sqlite3 "$DB" "$db_insert"
                unset start_times["$conferenceId"]
            fi
        fi
    # We don't use pipe, but process substitution '<(dd...)' to avoid running while loop in subshell and lose the 'new_last_pos' value
    done < <(dd bs=1 skip="$start_pos" <&3 2>/dev/null)

    # Close the file descriptor and return the new position value
    exec 3<&-
    echo "$new_last_pos"
}

# parse the rotated log file
if [[ "$last_file" == "$LOGFILE" && -f "$ROTATED_LOGFILE" ]]; then
    echo "Processing the rotated log file: $ROTATED_LOGFILE"
    last_pos=$(jvb_log_parse "$ROTATED_LOGFILE" 0)
    last_file="$ROTATED_LOGFILE"
    last_inode=$(stat -c '%i' "$ROTATED_LOGFILE")
    last_filetime=$(stat -c '%Y' "$ROTATED_LOGFILE")
    set_state "$last_file" "$last_filetime" "$last_pos" "$last_inode"
fi

# parse the current log file
echo "Processing the current log file: $LOGFILE"
new_last_pos=$(jvb_log_parse "$LOGFILE" "$last_pos")

# DEBUG
echo "New last position after parsing: $new_last_pos"

# update the state in db
set_state "$LOGFILE" "$current_filetime" "$new_last_pos" "$current_inode"

echo "Data import finished."