#! /bin/bash

set -e

produce_energy() {
    upower -e \
    | grep battery \
    | xargs upower -i \
    | awk '
        /^ +percentage: +/ { percentage=$2 }
        /^ +state: +/      { state=$2 }
        END                { print(state, percentage) }
        '
}


produce_memory() {
    free | awk '$1 == "Mem:" {print $2, $3}'
}

produce_fan() {
    fan_path="$1"
    cat "$fan_path"
}

produce_temperature() {
    thermal_zone="$1"
    cat "/sys/class/thermal/thermal_zone${thermal_zone}/temp"
}

produce_loadavg() {
    cat /proc/loadavg
}

produce_disk_io() {
    disk_io_device="$1"
    awk '
        {
            r = $3
            w = $7
            print w, r
        }
        ' "/sys/block/$disk_io_device/stat"
}

produce_disk_space() {
    disk_space_device="$1"
    df --output=pcent "$disk_space_device" | awk 'NR == 2 {print $1}'
}

produce_net_addr_io() {
    ip -s addr \
    | awk '
        BEGIN {
            bytes_per_unit = 1024 * 1024
        }

        /^[0-9]+:/ {
            sub(":$", "", $1)
            sub(":$", "", $2)
            sequence = $1
            interface = $2
            interfaces[sequence] = interface
        }

        /^ +inet [0-9]/ {
            sub("/[0-9]+", "", $2)
            addr = $2
            addrs[interface] = addr
        }

        /^ +RX: / {transfer_direction = "r"}
        /^ +TX: / {transfer_direction = "w"}

        /^ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ +[0-9]+ *$/ {
            io[interface, transfer_direction] = $1;
        }

        END {
            for (seq=1; seq<=sequence; seq++) {
                interface = interfaces[seq]
                label = substr(interface, 1, 1)
                if (addrs[interface]) {
                    curr_read  = io[interface, "r"]
                    curr_write = io[interface, "w"]
                    print(interface, addrs[interface], curr_write, curr_read)
                } else {
                    print(interface)
                }
            }
        }'
}

produce_net_wifi_status() {
    nmcli \
        -f ACTIVE,SSID,SIGNAL \
        -t \
        d wifi \
    | awk \
        -F ':' \
        '
        BEGIN       {wifi_status = "--"}
        $1 == "yes" {wifi_status =  $2 ":" $3 "%"}
        END         {print wifi_status}
        '
}

produce_bluetooth_power() {
    echo -e 'show \n quit' \
    | bluetoothctl \
    | awk '
        /^Controller / {
            controller = $2;
            controllers[++ctrl_count] = controller;
        }
        /^\t[A-Z][A-Za-z]+:/ {
            key = $1;
            sub(":$", "", key);
            val = $2;
            for (i=3; i<=NF; i++) {
                val = val " " $i};
                data[controller, key] = val;
        }
        END {
            # Using the 1st seen controller. Should we select specific instead?
            power_status = data[controllers[1], "Powered"];
            if (ctrl_count > 0) {
                if (power_status == "no") {
                    power_status = "off"
                } else if (power_status == "yes") {
                    power_status = "on"
                } else {
                    printf("Unexpected bluetooth power status: %s\n", power_status)\
                        > "/dev/stderr";
                    power_status = "ERROR"
                }
            } else {
                power_status = "off"  # TODO: Perhaps use differentiated marker?
            }
            printf("%s\n", power_status);
        }'
}

produce_screen_brightness() {
    screen_brightness_device_path="$1"
    echo "\
        $(cat $screen_brightness_device_path/max_brightness) \
        $(cat $screen_brightness_device_path/brightness)\
    "
}

produce_volume() {
    pactl list sinks \
    | awk '
        /^\tMute:/ {
            printf("%s,", $0);
        }
        /^\tVolume:/ {
            for (i=2; i<=NF; i++) printf(" %s", $i);
        }' \
    | awk -v RS=',' '
        /^[ \t]*Mute:/        {mute  = $2}
        /^[ \t]*front-left:/  {left  = $4}
        /^[ \t]*front-right:/ {right = $4}
        END {
            if (mute == "yes") {
                print("x")
            } else {
                print("%s %s\n", left, right)
            }
        }
        '
}

produce_mpd_state() {
    echo 'status' \
    | nc 127.0.0.1 6600 \
    | awk '
        {
            status[$1] = $2
        }

        /^time: +[0-9]+:[0-9]+$/ {
            split($2, time, ":")
            seconds_current = time[1]
            seconds_total   = time[2]

            hours = int(seconds_current / 60 / 60);
            secs_beyond_hours = seconds_current - (hours * 60 * 60);
            mins = int(secs_beyond_hours / 60);
            secs = secs_beyond_hours - (mins * 60);
            if (hours > 0) {
                current_time = sprintf("%d:%.2d:%.2d", hours, mins, secs)
            } else {
                current_time = sprintf("%.2d:%.2d", mins, secs)
            }

            if (seconds_total > 0) {
                time_percentage = (seconds_current / seconds_total) * 100
                current_percentage = sprintf("%d%%", time_percentage)
            } else {
                current_percentage = "~"
            }
        }

        END {
            state = status["state:"]

            if (state == "play") {
                symbol = "▶"
            } else if (state == "pause") {
                symbol = "❚❚"
            } else if (state == "stop") {
                symbol = "⬛"
            } else {
                symbol = "--"
            }

            printf(\
                "%s %s %s\n",
                status["state:"], current_time, current_percentage\
            )
        }
        '
}

produce_mpd_song() {
    echo 'currentsong' \
    | nc 127.0.0.1 6600 \
    | awk '
        /^OK/ {
            next
        }

        {
            key = $1
            sub("^" key " +", "")
            val = $0
            data[key] = val
        }

        END {
            name  = data["Name:"]
            title = data["Title:"]
            file  = data["file:"]

            if (name) {
                out = name
            } else if (title) {
                out = title
            } else if (file) {
                last = split(file, parts, "/")
                out = parts[last]
            } else {
                out = ""
            }
            print out
        }
        '
}

produce_weather() {
    weather_station_id="$1"
    metar -d "$weather_station_id" 2>&1 \
    | awk '
        /METAR pattern not found in NOAA data/ {
            failures++
        }

        /^Temperature/ {
            celsius = $3;
            fahrenheit = (celsius * (9 / 5)) + 32;
            temperature = fahrenheit
        }

        END {
            if (failures > 0) {
                temperature = "--"
            }
            print temperature "°F"
        }'
}

produce_datetime() {
    date +'%a %b %d %H:%M:%S'
}

consume() {
    pipe="$1"
    debug="$2"
    prefixes_of_net_interfaces_to_show="$3"
    tail -f "$pipe" \
    | stdbuf -o L awk \
        -v opt_debug="$debug" \
        -v opt_mpd_song_max_chars=10 \
        -v opt_prefixes_of_net_interfaces_to_show="$prefixes_of_net_interfaces_to_show" \
        '
            /^in:ENERGY/\
            {
                split_msg_parts()
                db["energy_state"]      = $1
                db["energy_percentage"] = $2
            }

            /^in:MEMORY/\
            {
                split_msg_parts()
                db["memory_total"] = $1
                db["memory_used"]  = $2
            }

            /^in:FAN +status:/\
            {
                split_msg_parts()
                db["fan_status"] = $2
            }

            /^in:FAN +speed:/\
            {
                split_msg_parts()
                db["fan_speed"] = $2
            }

            /^in:FAN +level:/\
            {
                split_msg_parts()
                db["fan_level"] = $2
            }

            /^in:TEMPERATURE/\
            {
                split_msg_parts()
                db["temperature"] = $1
            }

            /^in:LOAD_AVG/\
            {
                split_msg_parts()
                set_load_avg()
            }

            /^in:DISK_IO/\
            {
                split_msg_parts()
                set_disk_io()
            }

            /^in:DISK_SPACE/\
            {
                split_msg_parts()
                db["disk_space_used"] = msg_body
            }

            /^in:NET_ADDR_IO/\
            {
                split_msg_parts()
                set_net_addr_io()
            }

            /^in:NET_WIFI_STATUS/\
            {
                split_msg_parts()
                db["net_wifi_status"] = msg_body
            }

            /^in:BLUETOOTH_POWER/\
            {
                split_msg_parts()
                db["bluetooth_power"] = msg_body
            }

            /^in:SCREEN_BRIGHTNESS/\
            {
                split_msg_parts()
                set_screen_brightness()
            }

            /^in:VOLUME/\
            {
                split_msg_parts()
                db["volume"] = msg_body
            }

            /^in:MPD_STATE/\
            {
                split_msg_parts()
                db["mpd_state"]             = $1
                db["mpd_curr_song_time"]    = $2
                db["mpd_curr_song_percent"] = $3
            }

            /^in:MPD_SONG/\
            {
                split_msg_parts()
                db["mpd_curr_song_name"] = msg_body
            }

            /^in:WEATHER/\
            {
                split_msg_parts()
                db["weather_temperature"] = msg_body
            }

            /^in:DATE_TIME/\
            {
                split_msg_parts()
                db["datetime"] = msg_body
            }

            /^out:BAR/\
            {
                split_msg_parts()
                print make_bar()
            }

            function set_load_avg(    sched) {
                split($4, sched, "/")
                db["load_avg_1min"]             = $1
                db["load_avg_5min"]             = $2
                db["load_avg_15min"]            = $3
                db["kern_sched_queue_runnable"] = sched[1]
                db["kern_sched_queue_total"]    = sched[2]
                db["kern_sched_latest_pid"]     = $5
            }

            function set_disk_io(    curr_w, curr_r, prev_w, prev_r) {
                curr_w = $1
                curr_r = $2
                prev_w = db["disk_io_curr_w"]
                prev_r = db["disk_io_curr_r"]
                db["disk_io_curr_w"] = curr_w
                db["disk_io_curr_r"] = curr_r
                db["disk_io_diff_w"] = curr_w - prev_w
                db["disk_io_diff_r"] = curr_r - prev_r
            }

            function set_net_addr_io(    \
                interface, address, io_curr_w, io_curr_r, io_prev_w, io_prev_r\
            ) {
                interface = $1
                address   = $2
                io_curr_w = $3
                io_curr_r = $4
                if (interface) {
                    if (address && io_curr_w && io_curr_r) {
                        # recalculate
                        io_prev_w = net_io_curr_w[interface]
                        io_prev_r = net_io_curr_r[interface]

                        net_addr[interface]      = address
                        net_io_curr_w[interface] = io_curr_w
                        net_io_curr_r[interface] = io_curr_r
                        net_io_diff_w[interface] = io_curr_w - io_prev_w
                        net_io_diff_r[interface] = io_curr_r - io_prev_r
                    } else {
                        # clear
                        net_addr[interface]      = ""
                        net_io_curr_w[interface] = 0
                        net_io_curr_r[interface] = 0
                        net_io_diff_w[interface] = 0
                        net_io_diff_r[interface] = 0
                    }
                }
            }

            function set_screen_brightness(    max, cur) {
                max = $1
                cur = $2
                db["screen_brightness"] = (cur / max) * 100
            }

            function split_msg_parts() {
                msg_head = $1
                sub("^" msg_head " +", "")
                msg_body = $0
                debug(msg_head, msg_body)
            }

            function make_bar(    position, bar, sep, i, j) {
                position[++i] = make_status_energy()
                position[++i] = make_status_mem()
                position[++i] = make_status_cpu()
                position[++i] = make_status_disk()
                position[++i] = make_status_net()
                position[++i] = sprintf("B=%s", db["bluetooth_power"])
                position[++i] = sprintf("*%d%%", db["screen_brightness"])
                position[++i] = sprintf("(%s)", db["volume"])
                position[++i] = make_status_mpd()
                position[++i] = db["weather_temperature"]
                position[++i] = db["datetime"]
                bar = ""
                sep = ""
                for (j = 1; j <= i; j++) {
                    bar = bar sep position[j]
                    sep = " "
                }
                return bar
            }

            function make_status_energy(    state, direction_of_change) {
                state = db["energy_state"]
                if (state == "discharging") {
                    direction_of_change = "<"
                } else if (state == "charging") {
                    direction_of_change = ">"
                } else {
                    direction_of_change = "="
                };
                printf("E%s%s", direction_of_change, db["energy_percentage"])
            }

            function make_status_mem(    total, used, percent, status) {
                total = db["memory_total"]
                used  = db["memory_used"]
                # To avoid division by zero when data is missing
                if (total && used) {
                    percent = round((used / total) * 100)
                    status = sprintf("%d%%", percent)
                } else {
                    status = "__"
                }
                return sprintf("M=%s", status)
            }

            function make_status_cpu(    load, temp, fan) {
                load = db["load_avg_1min"]
                temp = db["temperature"] / 1000
                fan  = db["fan_speed"]
                return sprintf("C=[%4.2f %d°C %4drpm]", load, temp, fan)
            }

            function make_status_disk(    bytes_per_sector, bytes_per_mb, w, r) {
                bytes_per_sector = 512
                bytes_per_mb     = 1024 * 1024
                w = (db["disk_io_diff_w"] * bytes_per_sector) / bytes_per_mb
                r = (db["disk_io_diff_r"] * bytes_per_sector) / bytes_per_mb
                return \
                    sprintf("D=[%s %0.3f▲ %0.3f▼]", db["disk_space_used"], w, r)
            }

            function make_status_net(    \
                out,
                number_of_interfaces_to_show,
                n,
                array_of_prefixes_of_interfaces_to_show,
                prefix,
                interface,
                label,
                count_printed,
                sep,
                io_stat,
                dw, dr,
                bytes_per_unit\
            ) {
                out = ""
                number_of_interfaces_to_show = \
                    split(\
                        opt_prefixes_of_net_interfaces_to_show,\
                        array_of_prefixes_of_interfaces_to_show,\
                        ","\
                    )
                for (n = 1; n <= number_of_interfaces_to_show; n++) {
                    prefix = array_of_prefixes_of_interfaces_to_show[n]
                    for (interface in net_addr) {
                        if (interface ~ ("^" prefix)) {
                            label = substr(interface, 1, 1)
                            if (net_addr[interface]) {
                                bytes_per_mb = 1024 * 1024  # TODO: option
                                dw = net_io_diff_w[interface] / bytes_per_mb
                                dr = net_io_diff_r[interface] / bytes_per_mb
                                io_stat = sprintf("%0.3f▲ %0.3f▼", dw, dr)
                            } else {
                                io_stat = "--"
                            }
                            if (interface ~ "^w") {
                                label = label ":" db["net_wifi_status"]
                            }
                            if (++count_printed > 1) {
                                sep = "  "
                            } else {
                                sep = ""
                            }
                            out = out sep label ":" io_stat
                        }
                    }
                }
                return sprintf("N[%s]", out)
            }

            function make_status_mpd(    state, status) {
                state = db["mpd_state"]

                if (state == "play") {
                    status = make_status_mpd_state_known("▶")
                } else if (state == "pause") {
                    status = make_status_mpd_state_known("❚❚")
                } else if (state == "stop") {
                    status = make_status_mpd_state_known("⬛")
                } else {
                    status = make_status_mpd_state_unknown("--")
                }

                return sprintf("[%s]", status)
            }

            function make_status_mpd_state_known(symbol) {
                return sprintf(\
                    "%s %s %s %s",
                    symbol,
                    db["mpd_curr_song_time"],
                    db["mpd_curr_song_percent"],
                    substr(db["mpd_curr_song_name"], 1, opt_mpd_song_max_chars)\
                )
            }

            function make_status_mpd_state_unknown(symbol) {
                return sprintf("%s", symbol)
            }

            function round(n) {
                return int(n + 0.5)
            }

            function debug(location, msg) {
                if (opt_debug) {
                    print_error(location, msg)
                }
            }

            function print_error(location, msg) {
                print(location " ==> " msg) > "/dev/stderr"
            }
        '
}

produce_bar_req() {
    echo ''
}

spawn() {
    cmd="$1"
    pipe="$2"
    msg_head="$3"
    interval="$4"
    while true; do
        $cmd | while read line; do
            echo "${msg_head} $line" > "$pipe"
        done
        sleep "$interval"
    done &
}

main() {
    # Defaults
    debug=0
    dir_data=$(mktemp -d)
    weather_station_id='KJFK'
    screen_brightness_device_name='acpi_video0'
    prefixes_of_net_interfaces_to_show='w'  # comma-separated
    disk_space_device='/'
    disk_io_device='sda'
    thermal_zone=0
    fan_path='/proc/acpi/ibm/fan'

    # User-overrides
    long_options=''
    long_options+='debug'
    long_options+=',data_dir:'
    long_options+=',weather_station:'
    long_options+=',screen_device:'
    long_options+=',prefixes_of_net_interfaces_to_show:'
    long_options+=',disk_space_device:'
    long_options+=',disk_io_device:'
    long_options+=',thermal_zone:'
    long_options+=',fan_path:'
    OPTS=$(
        getopt \
            -o 'd' \
            -l $long_options \
            -- "$@"
    )
    eval set -- "$OPTS"
    while true
    do
        case "$1" in
            -d|--debug)
                debug=1
                shift
                ;;
            --data_dir)
                dir_data="$2"
                shift 2
                ;;
            --weather_station)
                weather_station_id="$2"
                shift 2
                ;;
            --screen_device)
                screen_brightness_device_name="$2"
                shift 2
                ;;
            --prefixes_of_net_interfaces_to_show)
                prefixes_of_net_interfaces_to_show="$2"
                shift 2
                ;;
            --disk_space_device)
                disk_space_device="$2"
                shift 2
                ;;
            --disk_io_device)
                disk_io_device="$2"
                shift 2
                ;;
            --thermal_zone)
                thermal_zone="$2"
                shift 2
                ;;
            --fan_path)
                fan_path="$2"
                shift 2
                ;;
            --)
                shift
                break
                ;;
        esac
    done

    pipe="$dir_data/khatus_data_pipe"
    screen_brightness_device_path='/sys/class/backlight'
    screen_brightness_device_path+="/$screen_brightness_device_name"

    ( echo "Khatus starting with the following parameters:"
      ( echo "    debug|= $debug"
        echo "    dir_data|= $dir_data"
        echo "    pipe|= $pipe"
        echo "    screen_brightness_device_name|= $screen_brightness_device_name"
        echo "    screen_brightness_device_path|= $screen_brightness_device_path"
        echo "    weather_station_id|= $weather_station_id"
        echo "    prefixes_of_net_interfaces_to_show|= $prefixes_of_net_interfaces_to_show"
        echo "    disk_space_device|= $disk_space_device"
        echo "    disk_io_device|= $disk_io_device"
        echo "    thermal_zone|= $thermal_zone"
        echo "    fan_path|= $fan_path"
      ) | column -ts\|
      echo ''
    ) >&2

    mkdir -p "$dir_data"
    rm -f "$pipe"
    mkfifo "$pipe"

    cmd_produce_screen_brightness='produce_screen_brightness'
    cmd_produce_screen_brightness+=" $screen_brightness_device_path"

    cmd_produce_weather="produce_weather $weather_station_id"

    cmd_produce_disk_space="produce_disk_space $disk_space_device"

    cmd_produce_disk_io="produce_disk_io $disk_io_device"

    cmd_produce_temperature="produce_temperature $thermal_zone"

    cmd_produce_fan="produce_fan $fan_path"

    # TODO: Redirect each worker's stderr to a dedicated log file
    spawn produce_datetime                 "$pipe" 'in:DATE_TIME' 1
    spawn "$cmd_produce_screen_brightness" "$pipe" 'in:SCREEN_BRIGHTNESS' 1
    spawn "$cmd_produce_weather"           "$pipe" 'in:WEATHER'   $(( 30 * 60 ))
    spawn produce_mpd_state                "$pipe" 'in:MPD_STATE' 1
    spawn produce_mpd_song                 "$pipe" 'in:MPD_SONG'  1
    spawn produce_volume                   "$pipe" 'in:VOLUME'    1
    spawn produce_bluetooth_power          "$pipe" 'in:BLUETOOTH_POWER' 5
    spawn produce_net_wifi_status          "$pipe" 'in:NET_WIFI_STATUS' 5
    spawn produce_net_addr_io              "$pipe" 'in:NET_ADDR_IO' 1
    spawn "$cmd_produce_disk_space"        "$pipe" 'in:DISK_SPACE' 1
    spawn "$cmd_produce_disk_io"           "$pipe" 'in:DISK_IO' 1
    spawn produce_loadavg                  "$pipe" 'in:LOAD_AVG' 1
    spawn "$cmd_produce_temperature"       "$pipe" 'in:TEMPERATURE' 1
    spawn "$cmd_produce_fan"               "$pipe" 'in:FAN' 1
    spawn produce_memory                   "$pipe" 'in:MEMORY' 1
    spawn produce_energy                   "$pipe" 'in:ENERGY' 1
    spawn produce_bar_req                  "$pipe" 'out:BAR'      1

    consume \
      "$pipe" \
      "$debug" \
      "$prefixes_of_net_interfaces_to_show"
}

main $@