#!/bin/sh

## A bit of helper functions...
# Check which type of init system we're running on
if [ -d /etc/upstart ]; then
    export INIT_TYPE="upstart"
    # We'll need that for logging
    # shellcheck disable=SC1091
    [ -f /etc/upstart/functions ] && . /etc/upstart/functions
else
    export INIT_TYPE="sysv"
    # We'll need that for logging
    # shellcheck disable=SC1091
    [ -f /etc/rc.d/functions ] && . /etc/rc.d/functions
fi

# We need to get the proper constants for our model...
kmodel="$(cut -c3-4 /proc/usid)"
case "${kmodel}" in
    "13" | "54" | "2A" | "4F" | "52" | "53")
        # Voyage...
        SCREEN_X_RES=1088 # NOTE: Yes, 1088, not 1072 or 1080...
        SCREEN_Y_RES=1448
        EIPS_X_RES=16
        EIPS_Y_RES=24 # Manually mesured, should be accurate.
        ;;
    "24" | "1B" | "1D" | "1F" | "1C" | "20" | "D4" | "5A" | "D5" | "D6" | "D7" | "D8" | "F2" | "17" | "60" | "F4" | "F9" | "62" | "61" | "5F")
        # PaperWhite...
        SCREEN_X_RES=768 # NOTE: Yes, 768, not 758...
        SCREEN_Y_RES=1024
        EIPS_X_RES=16
        EIPS_Y_RES=24 # Manually mesured, should be accurate.
        ;;
    "C6" | "DD")
        # KT2...
        SCREEN_X_RES=608
        SCREEN_Y_RES=800
        EIPS_X_RES=16
        EIPS_Y_RES=24
        ;;
    "0F" | "11" | "10" | "12")
        # Touch
        SCREEN_X_RES=600 # _v_width @ upstart/functions
        SCREEN_Y_RES=800 # _v_height @ upstart/functions
        EIPS_X_RES=12    # from f_puts @ upstart/functions
        EIPS_Y_RES=20    # from f_puts @ upstart/functions
        ;;
    *)
        # Handle legacy devices...
        if [ -f "/etc/rc.d/functions" ] && grep "EIPS" "/etc/rc.d/functions" >/dev/null 2>&1; then
            # Already done...
            #. /etc/rc.d/functions
            echo "foo" >/dev/null
        else
            # Try the new device ID scheme...
            kmodel="$(cut -c4-6 /proc/usid)"
            case "${kmodel}" in
                "0G1" | "0G2" | "0G4" | "0G5" | "0G6" | "0G7" | "0KB" | "0KC" | "0KD" | "0KE" | "0KF" | "0KG")
                    # PW3... NOTE: Hopefully matches the KV...
                    SCREEN_X_RES=1088
                    SCREEN_Y_RES=1448
                    EIPS_X_RES=16
                    EIPS_Y_RES=24
                    ;;
                "0GC" | "0GD" | "0GP" | "0GQ" | "0GR" | "0GS")
                    # Oasis... NOTE: Hopefully matches the KV...
                    SCREEN_X_RES=1088
                    SCREEN_Y_RES=1448
                    EIPS_X_RES=16
                    EIPS_Y_RES=24
                    ;;
                "0DT" | "0K9" | "0KA")
                    # KT3... NOTE: Hopefully matches the KT2...
                    SCREEN_X_RES=608
                    SCREEN_Y_RES=800
                    EIPS_X_RES=16
                    EIPS_Y_RES=24
                    ;;
                *)
                    # Fallback... We shouldn't ever hit that.
                    SCREEN_X_RES=600
                    SCREEN_Y_RES=800
                    EIPS_X_RES=12
                    EIPS_Y_RES=20
                    ;;
            esac
        fi
        ;;
esac
# And now we can do the maths ;)
EIPS_MAXCHARS="$((SCREEN_X_RES / EIPS_X_RES))"
EIPS_MAXLINES="$((SCREEN_Y_RES / EIPS_Y_RES))"

# Adapted from libkh[5]
eips_print_bottom_centered() {
    # We need at least two args
    if [ $# -lt 2 ]; then
        echo "not enough arguments passed to eips_print_bottom ($# while we need at least 2)"
        return
    fi

    kh_eips_string="${1}"
    kh_eips_y_shift_up="${2}"

    # Get the real string length now
    kh_eips_strlen="${#kh_eips_string}"

    # Add the right amount of left & right padding, since we're centered, and eips doesn't trigger a full refresh,
    # so we'll have to padd our string with blank spaces to make sure two consecutive messages don't run into each other
    kh_padlen="$(((EIPS_MAXCHARS - kh_eips_strlen) / 2))"

    # Left padding...
    while [ ${#kh_eips_string} -lt $((kh_eips_strlen + kh_padlen)) ]; do
        kh_eips_string=" ${kh_eips_string}"
    done

    # Right padding (crop to the edge of the screen)
    while [ ${#kh_eips_string} -lt ${EIPS_MAXCHARS} ]; do
        kh_eips_string="${kh_eips_string} "
    done

    # Sleep a tiny bit to workaround the logic in the 'new' (K4+) eInk controllers that tries to bundle updates,
    # otherwise it may drop part of our messages because of other screen updates from KUAL...
    # Unless we really don't want to sleep, for special cases...
    if [ ! -n "${EIPS_NO_SLEEP}" ]; then
        usleep 150000 # 150ms
    fi

    # And finally, show our formatted message centered on the bottom of the screen (NOTE: Redirect to /dev/null to kill unavailable character & pixel not in range warning messages)
    eips 0 $((EIPS_MAXLINES - 2 - kh_eips_y_shift_up)) "${kh_eips_string}" >/dev/null
}