#!/bin/sh
export LC_ALL="en_US.UTF-8"

# working directory of koreader
KOREADER_DIR="${0%/*}"

# we're always starting from our working directory
cd "${KOREADER_DIR}" || exit

# Attempt to switch to a sensible CPUFreq governor when that's not already the case...
current_cpufreq_gov="$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor)"
# NOTE: We're being fairly conservative here, because what's used and what's available varies depending on HW...
if [ "${current_cpufreq_gov}" != "ondemand" ] && [ "${current_cpufreq_gov}" != "interactive" ]; then
    # NOTE: Go with ondemand, because it's likely to be the lowest common denominator.
    #       Plus, interactive is hard to tune right, and only really interesting when it's a recent version,
    #       which I somehow doubt is the case anywhere here...
    if grep -q ondemand /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors; then
        ORIG_CPUFREQ_GOV="${current_cpufreq_gov}"
        echo "ondemand" >"/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor"
    fi
fi
# NOTE: That doesn't actually help us poor userspace plebs, but, short of switching to performance,
#       I don't really have a golden bullet here... (conservative's rubberbanding is terrible, so that's a hard pass).
#       All I can say is that userspace is a terrible idea and behaves *very* strangely (c.f., #4114).

# update to new version from OTA directory
ko_update_check() {
    NEWUPDATE="${KOREADER_DIR}/ota/koreader.updated.tar"
    INSTALLED="${KOREADER_DIR}/ota/koreader.installed.tar"
    if [ -f "${NEWUPDATE}" ]; then
        ./fbink -q -y -7 -pmh "Updating KOReader"
        # NOTE: See frontend/ui/otamanager.lua for a few more details on how we squeeze a percentage out of tar's checkpoint feature
        # NOTE: %B should always be 512 in our case, so let stat do part of the maths for us instead of using %s ;).
        FILESIZE="$(stat -c %b "${NEWUPDATE}")"
        BLOCKS="$((FILESIZE / 20))"
        export CPOINTS="$((BLOCKS / 100))"
        # shellcheck disable=SC2016
        ./tar xf "${NEWUPDATE}" --strip-components=1 --no-same-permissions --no-same-owner --checkpoint="${CPOINTS}" --checkpoint-action=exec='./fbink -q -y -6 -P $(($TAR_CHECKPOINT/$CPOINTS))'
        fail=$?
        # Cleanup behind us...
        if [ "${fail}" -eq 0 ]; then
            mv "${NEWUPDATE}" "${INSTALLED}"
            ./fbink -q -y -6 -pm "Update successful :)"
            ./fbink -q -y -5 -pm "KOReader will start momentarily . . ."
        else
            # Uh oh...
            ./fbink -q -y -6 -pmh "Update failed :("
            ./fbink -q -y -5 -pm "KOReader may fail to function properly!"
        fi
        rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
        unset BLOCKS CPOINTS
        # Ensure everything is flushed to disk before we restart. This *will* stall for a while on slow storage!
        sync
    fi
}
# NOTE: Keep doing an initial update check, in addition to one during the restart loop, so we can pickup potential updates of this very script...
ko_update_check
# If an update happened, and was successful, reexec
if [ -n "${fail}" ] && [ "${fail}" -eq 0 ]; then
    # By now, we know we're in the right directory, and our script name is pretty much set in stone, so we can forgo using $0
    exec ./koreader.sh "${@}"
fi

# load our own shared libraries if possible
export LD_LIBRARY_PATH="${KOREADER_DIR}/libs:${LD_LIBRARY_PATH}"

# export trained OCR data directory
export TESSDATA_PREFIX="data"

# export dict directory
export STARDICT_DATA_DIR="data/dict"

# export external font directory
export EXT_FONT_DIR="/mnt/onboard/fonts"

# fast and dirty way of check if we are called from nickel
# through fmon/KFMon, or from another launcher (KSM or advboot)
# Do not delete this line because KSM detects newer versions of KOReader by the presence of the phrase 'from_nickel'.
export FROM_NICKEL="false"
if pkill -0 nickel; then
    FROM_NICKEL="true"
fi

if [ "${FROM_NICKEL}" = "true" ]; then
    # Detect if we were started from KFMon
    FROM_KFMON="false"
    if pkill -0 kfmon; then
        # That's a start, now check if KFMon truly is our parent...
        if [ "$(pidof kfmon)" -eq "${PPID}" ]; then
            FROM_KFMON="true"
        fi
    fi

    # Siphon a few things from nickel's env (namely, stuff exported by rcS *after* on-animator.sh has been launched)...
    eval "$(xargs -n 1 -0 <"/proc/$(pidof nickel)/environ" | grep -e DBUS_SESSION_BUS_ADDRESS -e NICKEL_HOME -e WIFI_MODULE -e LANG -e WIFI_MODULE_PATH -e INTERFACE 2>/dev/null)"
    export DBUS_SESSION_BUS_ADDRESS NICKEL_HOME WIFI_MODULE LANG WIFI_MODULE_PATH INTERFACE

    # flush disks, might help avoid trashing nickel's DB...
    sync
    # stop kobo software because it's running
    # NOTE: We don't need to kill KFMon, it's smart enough not to allow running anything else while we're up
    killall -TERM nickel hindenburg sickel fickel fmon 2>/dev/null
fi

# fallback for old fmon, KFMon and advboot users (-> if no args were passed to the script, start the FM)
if [ "$#" -eq 0 ]; then
    args="/mnt/onboard"
else
    args="$*"
fi

# check whether PLATFORM & PRODUCT have a value assigned by rcS
if [ -z "${PRODUCT}" ]; then
    PRODUCT="$(/bin/kobo_config.sh 2>/dev/null)"
    export PRODUCT
fi

# PLATFORM is used in koreader for the path to the WiFi drivers (as well as when restarting nickel)
if [ -z "${PLATFORM}" ]; then
    PLATFORM="freescale"
    if dd if="/dev/mmcblk0" bs=512 skip=1024 count=1 | grep -q "HW CONFIG"; then
        CPU="$(ntx_hwconfig -s -p /dev/mmcblk0 CPU 2>/dev/null)"
        PLATFORM="${CPU}-ntx"
    fi

    if [ "${PLATFORM}" != "freescale" ] && [ ! -e "/etc/u-boot/${PLATFORM}/u-boot.mmc" ]; then
        PLATFORM="ntx508"
    fi
    export PLATFORM
fi

# Make sure we have a sane-ish INTERFACE env var set...
if [ -z "${INTERFACE}" ]; then
    # That's what we used to hardcode anyway
    INTERFACE="eth0"
    export INTERFACE
fi
# end of value check of PLATFORM

# We'll want to ensure Portrait rotation to allow us to use faster blitting codepaths @ 8bpp,
# so remember the current one before fbdepth does its thing.
ORIG_FB_ROTA="$(cat /sys/class/graphics/fb0/rotate)"
echo "Original fb rotation is set @ ${ORIG_FB_ROTA}" >>crash.log 2>&1

# In the same vein, swap to 8bpp,
# because 16bpp is the worst idea in the history of time, as RGB565 is generally a PITA without hardware blitting,
# and 32bpp usually gains us nothing except a performance hit (we're not Qt5 with its QPainter constraints).
# The reduced size & complexity should hopefully make things snappier,
# (and hopefully prevent the JIT from going crazy on high-density screens...).
# NOTE: Even though both pickel & Nickel appear to restore their preferred fb setup, we'll have to do it ourselves,
#       as they fail to flip the grayscale flag properly. Plus, we get to play nice with every launch method that way.
#       So, remember the current bitdepth, so we can restore it on exit.
ORIG_FB_BPP="$(./fbdepth -g)"
echo "Original fb bitdepth is set @ ${ORIG_FB_BPP}bpp" >>crash.log 2>&1
# Sanity check...
case "${ORIG_FB_BPP}" in
    16) ;;
    32) ;;
    *)
        # Uh oh? Don't do anything...
        unset ORIG_FB_BPP
        ;;
esac

# The actual swap is done in a function, because we can disable it in the Developer settings, and we want to honor it on restart.
ko_do_fbdepth() {
    # Check if the swap has been disabled...
    if grep -q '\["dev_startup_no_fbdepth"\] = true' 'settings.reader.lua' 2>/dev/null; then
        # Swap back to the original bitdepth (in case this was a restart)
        if [ -n "${ORIG_FB_BPP}" ]; then
            # Unless we're a Forma/Libra, don't even bother to swap rotation if the fb is @ 16bpp, because RGB565 is terrible anyways,
            # so there's no faster codepath to achieve, and running in Portrait @ 16bpp might actually be broken on some setups...
            if [ "${ORIG_FB_BPP}" -eq "16" ] && [ "${PRODUCT}" != "frost" ] && [ "${PRODUCT}" != "storm" ]; then
                echo "Making sure we're using the original fb bitdepth @ ${ORIG_FB_BPP}bpp & rotation @ ${ORIG_FB_ROTA}" >>crash.log 2>&1
                ./fbdepth -d "${ORIG_FB_BPP}" -r "${ORIG_FB_ROTA}" >>crash.log 2>&1
            else
                echo "Making sure we're using the original fb bitdepth @ ${ORIG_FB_BPP}bpp, and that rotation is set to Portrait" >>crash.log 2>&1
                ./fbdepth -d "${ORIG_FB_BPP}" -r -1 >>crash.log 2>&1
            fi
        fi
    else
        # Swap to 8bpp if things looke sane
        if [ -n "${ORIG_FB_BPP}" ]; then
            echo "Switching fb bitdepth to 8bpp & rotation to Portrait" >>crash.log 2>&1
            ./fbdepth -d 8 -r -1 >>crash.log 2>&1
        fi
    fi
}

# Remount the SD card RW if it's inserted and currently RO
if awk '$4~/(^|,)ro($|,)/' /proc/mounts | grep ' /mnt/sd '; then
    mount -o remount,rw /mnt/sd
fi

# we keep at most 500KB worth of crash log
if [ -e crash.log ]; then
    tail -c 500000 crash.log >crash.log.new
    mv -f crash.log.new crash.log
fi

CRASH_COUNT=0
CRASH_TS=0
CRASH_PREV_TS=0
# Because we *want* an initial fbdepth pass ;).
RETURN_VALUE=85
while [ ${RETURN_VALUE} -ne 0 ]; do
    # 85 is what we return when asking for a KOReader restart
    if [ ${RETURN_VALUE} -eq 85 ]; then
        # Do an update check now, so we can actually update KOReader via the "Restart KOReader" menu entry ;).
        ko_update_check
        # Do or double-check the fb depth switch, or restore original bitdepth if requested
        ko_do_fbdepth
    fi

    ./reader.lua "${args}" >>crash.log 2>&1
    RETURN_VALUE=$?

    # Did we crash?
    if [ ${RETURN_VALUE} -ne 0 ] && [ ${RETURN_VALUE} -ne 85 ]; then
        # Increment the crash counter
        CRASH_COUNT=$((CRASH_COUNT + 1))
        CRASH_TS=$(date +'%s')
        # Reset it to a first crash if it's been a while since our last crash...
        if [ $((CRASH_TS - CRASH_PREV_TS)) -ge 20 ]; then
            CRASH_COUNT=1
        fi

        # Check if the user requested to always abort on crash
        if grep -q '\["dev_abort_on_crash"\] = true' 'settings.reader.lua' 2>/dev/null; then
            ALWAYS_ABORT="true"
            # In which case, make sure we pause on *every* crash
            CRASH_COUNT=1
        else
            ALWAYS_ABORT="false"
        fi

        # Show a fancy bomb on screen
        viewWidth=600
        viewHeight=800
        FONTH=16
        eval "$(./fbink -e | tr ';' '\n' | grep -e viewWidth -e viewHeight -e FONTH | tr '\n' ';')"
        # Compute margins & sizes relative to the screen's resolution, so we end up with a similar layout, no matter the device.
        # Height @ ~56.7%, w/ a margin worth 1.5 lines
        bombHeight=$((viewHeight / 2 + viewHeight / 15))
        bombMargin=$((FONTH + FONTH / 2))
        # With a little notice at the top of the screen, on a big gray screen of death ;).
        ./fbink -q -b -c -B GRAY9 -m -y 1 "Don't Panic! (Crash n°${CRASH_COUNT} -> ${RETURN_VALUE})"
        if [ ${CRASH_COUNT} -eq 1 ]; then
            # Warn that we're waiting on a tap to continue...
            ./fbink -q -b -O -m -y 2 "Tap the screen to continue."
        fi
        # U+1F4A3, the hard way, because we can't use \u or \U escape sequences...
        # shellcheck disable=SC2039
        ./fbink -q -b -O -m -t regular=./fonts/freefont/FreeSerif.ttf,px=${bombHeight},top=${bombMargin} $'\xf0\x9f\x92\xa3'
        # And then print the tail end of the log on the bottom of the screen...
        crashLog="$(tail -n 25 crash.log | sed -e 's/\t/    /g')"
        # The idea for the margins being to leave enough room for an fbink -Z bar, small horizontal margins, and a font size based on what 6pt looked like @ 265dpi
        ./fbink -q -b -O -t regular=./fonts/droid/DroidSansMono.ttf,top=$((viewHeight / 2 + FONTH * 2 + FONTH / 2)),left=$((viewWidth / 60)),right=$((viewWidth / 60)),px=$((viewHeight / 64)) "${crashLog}"
        # So far, we hadn't triggered an actual screen refresh, do that now, to make sure everything is bundled in a single flashing refresh.
        ./fbink -q -f -s top=0,left=0
        # Cue a lemming's faceplant sound effect!

        {
            echo "!!!!"
            echo "Uh oh, something went awry... (Crash n°${CRASH_COUNT}: $(date +'%x @ %X'))"
            echo "Running FW $(cut -f3 -d',' /mnt/onboard/.kobo/version) on Linux $(uname -r) ($(uname -v))"
        } >>crash.log 2>&1
        if [ ${CRASH_COUNT} -lt 5 ] && [ "${ALWAYS_ABORT}" = "false" ]; then
            echo "Attempting to restart KOReader . . ." >>crash.log 2>&1
            echo "!!!!" >>crash.log 2>&1
        fi

        # Pause a bit if it's the first crash in a while, so that it actually has a chance of getting noticed ;).
        if [ ${CRASH_COUNT} -eq 1 ]; then
            # NOTE: We don't actually care about what read read, we're just using it as a fancy sleep ;).
            #       i.e., we pause either until the 15s timeout, or until the user touches the screen.
            # shellcheck disable=SC2039
            read -r -t 15 </dev/input/event1
        fi
        # Cycle the last crash timestamp
        CRASH_PREV_TS=${CRASH_TS}

        # But if we've crashed more than 5 consecutive times, exit, because we wouldn't want to be stuck in a loop...
        # NOTE: No need to check for ALWAYS_ABORT, CRASH_COUNT will always be 1 when it's true ;).
        if [ ${CRASH_COUNT} -ge 5 ]; then
            echo "Too many consecutive crashes, aborting . . ." >>crash.log 2>&1
            echo "!!!! ! !!!!" >>crash.log 2>&1
            break
        fi

        # If the user requested to always abort on crash, do so.
        if [ "${ALWAYS_ABORT}" = "true" ]; then
            echo "Aborting . . ." >>crash.log 2>&1
            echo "!!!! ! !!!!" >>crash.log 2>&1
            break
        fi
    else
        # Reset the crash counter if that was a sane exit/restart
        CRASH_COUNT=0
    fi
done

# Restore original fb bitdepth if need be...
# Since we also (almost) always enforce Portrait, we also have to restore the original rotation no matter what ;).
if [ -n "${ORIG_FB_BPP}" ]; then
    echo "Restoring original fb bitdepth @ ${ORIG_FB_BPP}bpp & rotation @ ${ORIG_FB_ROTA}" >>crash.log 2>&1
    ./fbdepth -d "${ORIG_FB_BPP}" -r "${ORIG_FB_ROTA}" >>crash.log 2>&1
else
    echo "Restoring original fb rotation @ ${ORIG_FB_ROTA}" >>crash.log 2>&1
    ./fbdepth -r "${ORIG_FB_ROTA}" >>crash.log 2>&1
fi

# Restore original CPUFreq governor if need be...
if [ -n "${ORIG_CPUFREQ_GOV}" ]; then
    echo "${ORIG_CPUFREQ_GOV}" >"/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor"
fi

if [ "${FROM_NICKEL}" = "true" ]; then
    if [ "${FROM_KFMON}" != "true" ]; then
        # start kobo software because it was running before koreader
        ./nickel.sh &
    else
        if grep -q "reboot_on_exit=false" "/mnt/onboard/.adds/kfmon/config/koreader.ini" 2>/dev/null; then
            # KFMon asked us to restart nickel on exit (default since KFMon 0.9.5)
            ./nickel.sh &
        else
            # KFMon asked us to restart the device on exit
            /sbin/reboot
        fi
    fi
else
    # if we were called from advboot then we must reboot to go to the menu
    # NOTE: This is actually achieved by checking if KSM or a KSM-related script is running:
    #       This might lead to false-positives if you use neither KSM nor advboot to launch KOReader *without nickel running*.
    if ! pgrep -f kbmenu >/dev/null 2>&1; then
        /sbin/reboot
    fi
fi

exit ${RETURN_VALUE}