msg () {  # A status reporting function
    [ "${VERBOSE:-0}" -gt 0 ] && echo "$*"
}

error () { # An error reporting function
    echo 1>&2 "$*"
}

fatal () { # Report an error and exit with a failure code
    error "$*"
    exit 1
}

# The only non builtin this uses is tr...
require () { # Check prerequisites
    e=0
    props="$1" ; shift
    for obj in "$@" ; do
        [ -z "$obj" ] && continue # Too late to do anything itelligent...
        problems=""
        for prop in $(/bin/tr '+,' ' ' <<<"$props") ; do
            case "$prop" in
            e|exists) # kind of useless...
                [ -e "$obj" ] || problems="$problems, does not exist" ;;
            f|file)
                [ -f "$obj" ] || problems="$problems, is not a file" ;;
            d|dir)
                [ -d "$obj" ] || problems="$problems, is not a directory" ;;
            l|symlink)
                [ -L "$obj" ] || problems="$problems, is not a symlink" ;;
            nosymlink)
                [ -L "$obj" ] && problems="$problems, is a symlink" ;;
            r|readable)
                [ -r "$obj" ] || problems="$problems, is not readable" ;;
            w|writable)
                [ -w "$obj" ] || problems="$problems, is not writable" ;;
            x|executable)
                [ -x "$obj" ] || problems="$problems, is not executable" ;;
            *)
                fatal "Programmer error, unknown property: '$prop'" ;;
            esac
        done
        if [ -n "$problems" ] ; then
            error "Error: '$obj'$problems."
            e=1
        fi
    done
    [ "$e" -ne 0 ] && fatal "Errors noted above are fatal."
}

require file+r+x /bin/bash /bin/grep /bin/rm /bin/tr \
                 /usr/bin/basename /usr/bin/env \
                 /usr/bin/mysql /usr/bin/sort

if [ -n "$DEBUG" ] ; then
    for debug_opt in $(/bin/tr ',' ' ' <<<"$DEBUG") ; do
        echo '============================================================'
        echo "==== $debug_opt"

        # Note that the order you specifiy these debug options in matters.
        # I recommend always listing log first. For example:
        #   export DEBUG=log,env,set,trace
        case "$debug_opt" in
        env)    /usr/bin/env | /usr/bin/sort ;;
        set)    set ;;
        trace)  set -vx ;;
        log)    logfile="/tmp/$(/usr/bin/basename $0).$$.debug"
                /bin/rm -f "$logfile" # Try to avoid privilege escalation bugs
                echo "Redirecting stdout and stderr to '$logfile'"
                exec >"$logfile" 2>&1 ;;
        *)      error "Unknown debug option '$debug_opt'" ;;
        esac
    done
    echo '============================================================'
fi

must_be_root () { # For things which must be run as root
    [ $(/usr/bin/id -u) -ne 0 ] && fatal "You must run this script as root!"
}

must_be_mythtv () { # For things which must be run as mythtv (su if possible)
    case $(/usr/bin/id -nu) in
    mythtv) ;; # Continue
    root)   /bin/su - mythtv -c "$0 $*" ; exit $? ;;
    *)      fatal "You must run this script at mythtv or root!" ;;
    esac
}

# Use a variable so you can override it.
DATABASE="mythconverg"

mysql_cmd () { # Execute SQL from the command line
    /usr/bin/mysql -u root "$DATABASE" -sBe "$*"
}

mysql_stdin () { # Execute SQL from stdin
    /usr/bin/mysql -u root "$DATABASE" -sB
}

machine_clause () { # Helper function 
    if [ -z "$1" ] ; then
        echo "(hostname = '' or hostname is null)"
    else
        echo "hostname = '$1'"
    fi
}

get_all_setting_names () { # List setting names
    case "$#" in
    0) MACHINE_CLAUSE="" ;;
    1) MACHINE_CLAUSE="where $(machine_clause "$1")" ;;
    *) fatal "Programmer error, get_all_names must be passed 0 or 1 args, got $#" ;;
    esac
    mysql_cmd "select distinct value from settings $MACHINE_CLAUSE order by value"
}

get_all_setting_values () { # List settings
    case "$#" in
    0) MACHINE_CLAUSE="" ;;
    1) MACHINE_CLAUSE="where $(machine_clause "$1")" ;;
    *) fatal "Programmer error, get_all_values must be passed 0 or 1 args, got $#" ;;
    esac
    mysql_cmd "select value, data, hostname from settings $MACHINE_CLAUSE order by hostname, value, data"
}

get_setting_value () { # Get the data for a setting (may return multiples!)
    case "$#" in
    1) MACHINE_CLAUSE="" ;;
    2) MACHINE_CLAUSE="and $(machine_clause "$2")" ;;
    *) fatal "Programmer error, get_value must be passed 1 or 2 args, got $#" ;;
    esac
    mysql_cmd "select data from settings where value = '$1' $MACHINE_CLAUSE"
}

set_setting_value () { # Insert or update aome setting
    case "$#" in
    2) RECORD_CNT=$(get_value "$1" | wc -l) ;;
    3) RECORD_CNT=$(get_value "$1" "$3" | wc -l) ;;
    *) fatal "Programmer error, set_value must be passed 2 or 3 args, got $#" ;;
    esac
    MACHINE_CLAUSE=""
    if [ "$RECORD_CNT" -eq 0 ] ; then
        [ -n "$3" ] && MACHINE_CLAUSE=", $(machine_clause "$3")"
        mysql_cmd "insert into settings set value = '$1', data = '$2' $MACHINE_CLAUSE"
    else
        [ "$#" -eq 3 ] && MACHINE_CLAUSE="and $(machine_clause "$3")"
        mysql_cmd "update settings set data = '$2' where value = '$1' $MACHINE_CLAUSE"
    fi
}

delete_setting_value () { # Totally remove some setting
    case "$#" in
    1) MACHINE_CLAUSE="" ;;
    2) MACHINE_CLAUSE="and $(machine_clause "$2")" ;;
    *) fatal "Programmer error, get_value must be passed 1 or 2 args, got $#" ;;
    esac
    mysql_cmd "delete from settings where value = '$1' $MACHINE_CLAUSE"
}

# Filter against a newline seperated exclude list
filter_list () {
    /bin/grep -vxF "$*" |
    /usr/bin/sort -u
}