#!/bin/sh

# Parse arguments
# ------------------------------------------------------------------------------------
ALL=0
VERBOSE=0
VERY_VERBOSE=0
VERY_VERY_VERBOSE=0
TEMP_SHOW=0
DRY_RUN=0
NO_CACHE=0
NO_DISPLAY=0
MAX_AMOUNT=0
URGENCY="normal"
RESET=0
while [ "$1" ]; do
    case "$1" in
        -h | --help)
            cat << EOF
gh-notification is a tool that scrapes unread github notifications
It uses github-cli with meiji163/gh-notify addon to obtain the unread notifications
these are then parsed and sent as desktop notifications with notify-send

Options:
-a | --all: Also process already read notifications
-t | --temp-files: Show names of used temporary files for each notification
-v | --verbose: Shows info about what's happening.
-vv | --very-verbose: Implies --verbose, shows some more info about what's happening
-vvv | --very-very-verbose: Implies --very-verbose and --temp-files, shows even more details, usually just for debugging
-d | --dry-run: Run without sending any notificatinos, when ran with -r, this will also prevent any actual cache file removals
-nc | --no-cache: Ignore the cache and send all found notifications, even if they were already sent before.
-nd | --no-display: When the script is ran from headless mode (such as by crontab), this will still attempt to set the DISPLAY and send the desktop notification
-r | --reset: Resets notification cache (storing which notifications were already sent), skips notification sending, WARNING: removes the whole cache, regardless of '--all')
-u | --urgency [urgency-level]: pass over notify-send urgency attribute (low, normal, critical)
-n | --number [amount]: maximum amount of notifications to show
EOF
            exit 0
            ;;
        -a | --all)
            ALL=1
            ;;
        -t | --temp-files)
            TEMP_SHOW=1
            ;;
        -v | --verbose)
            VERBOSE=1
            ;;
        -vv | --very-verbose)
            VERBOSE=1
            VERY_VERBOSE=1
            ;;
        -vvv | --very-very-verbose)
            VERBOSE=1
            TEMP_SHOW=1
            VERY_VERBOSE=1
            VERY_VERY_VERBOSE=1
            ;;
        -d | --dry-run)
            DRY_RUN=1
            ;;
        -nc | --no-cache)
            NO_CACHE=1
            ;;
        -nd | --no-display)
            NO_DISPLAY=1
            ;;
        -u | --urgency)
            URGENCY="$2"
            shift
            ;;
        -n | --number)
            MAX_AMOUNT="$2"
            shift
            ;;
        -r | --reset)
            RESET=1
            ;;
        * ) 
            echo "Unknown argument '$1', use -h or --help for help" 
            exit 1
            ;;
    esac
    shift
done


# Perform cache resetting, if requested
# ------------------------------------------------------------------------------------
if [ $RESET -eq 1 ]; then
    if [ $NO_CACHE -eq 1 ]; then
        echo "Can't ignore cache when resetting the cache..."
        exit 1
    fi
    out="$(find /tmp -maxdepth 1 -name 'gh-notification-*' 2>/dev/null)"
    total="$(printf "%s\n" "$out" | wc -l)"
    # Since we always end with a newline (to count the last entry as a line), we always get
    # at least 1 as a total here, even if $out is empty. If we didn't use the \n, we'd always
    # get 0, even if there was a single line, since it wasn't ended with a newline. To figure
    # out whether there really is a line or not when we get a total of 1, we run character
    # amount check as well
    [ "$total" -eq 1 ] && [ "$(printf "%s" "$out" | wc -c)" -eq 0 ] && total=0

    if [ $total -gt 0 ]; then
        # Since the loop is running in a pipe, it can't modify variables, but we need to know
        # which files have failed to be removed, so to get that information, we store it in a
        # teporary file
        fail_files_file="$(mktemp)"

        printf "%s\n" "$out" | while read -r file_name; do
            # If desired, let user know about the found notification cache file
            if [ $VERY_VERBOSE -eq 1 ] || [ $TEMP_SHOW -eq 1 ]; then
                contents="$(cat "$file_name")"
                title="$(printf "%s" "$contents" | awk -F '~@~' '{ print $1 }')"

                echo "Found cache tempfile: '$file_name' - $title"
                if [ $VERY_VERY_VERBOSE -eq 1 ]; then 
                    description="$(printf "%s" "$contents" | awk -F '~@~' '{ print $2 }')"
                    echo "Notification description: $description"
                fi
            fi

            if [ $DRY_RUN -ne 1 ]; then
                # In case `rm` fails, keep track of which files it failed on
                if ! rm "$file_name" 2>/dev/null; then
                    printf "%s\n" "$file_name" >> "$fail_files_file"
                fi
            else
                [ $VERY_VERY_VERBOSE -eq 1 ] && echo "Tempfile removal skipped (dry-run)"
            fi

            # Add a new-line separator on very very verbose to group prints from each iteration
            [ $VERY_VERY_VERBOSE -eq 1 ] && echo ""
        done

        # Recover failed files from the temporary file
        failed_files="$(cat "$fail_files_file")"
        failed="$(printf "%s" "$fail_files_file" | wc -l)"
        rm "$fail_files_file"

        if [ $VERBOSE -eq 1 ]; then
            echo "Notification cache was reset."
            removed_count="$(("$total"-"$failed"))"
            if [ $DRY_RUN -eq 1 ]; then
                echo "Removed $removed_count files (dry-run: no files were actually removed)"
            else
                echo "Removed $removed_count files"
            fi
        fi

        # If some cache files were'nt removed successfully, inform the user about it
        # regardless of verbosity, this shouldn't go silent, even though it may be fine
        if [ "$failed" -gt 0 ]; then
            echo "WARNING: Failed to remove $failed files."
            echo "You probably don't have permission to remove these."
            echo "Perhaps these were made by someone else? If so, you can ignore this warning."
            if [ $VERBOSE -eq 0 ]; then
                echo "Run with --verbose to show exactly which files weren't removed."
            else
                echo "These are:"
                echo "$failed_files"
            fi
        fi
    else
        [ $VERBOSE -eq 1 ] && echo "No cache files found, nothing to reset"
    fi
    exit 0
fi


# Helper functins
# ------------------------------------------------------------------------------------
# This runs notify-send, and if NO_DISPLAY is set and we're running in headless
# mode, this will still try to send the notification by manually setting DISPLAY
# This also has a special handle that checks if dunst is the notification daemon
# in which case instead of using notify-send, we use dunstify to send the 
# notification, with which we can also specify some more values.
send_notify() {
    if [ $NO_DISPLAY -eq 1 ]; then
        XDG_RUNTIME_DIR="/run/user/$(id -u)" \
        DISPLAY=:0 \
        notify-send --app-name=github-notification --urgency="$URGENCY" "$1" "$2"
    else
        notify-send --app-name=github-notification --urgency="$URGENCY" "$1" "$2"
    fi
}


# Obtain notifications and show them, if they weren't showed (aren't in cache) already
# ------------------------------------------------------------------------------------
# Request unread notifications with gh-notify extension for github-cli
[ "$ALL" -eq 1 ] && out="$(gh notify -s -a -n "$MAX_AMOUNT")" || out="$(gh notify -s -n "$MAX_AMOUNT")"

# When no notifications were found, set output to empty string, to avoid 'All caught up!' line 
# being treated as notification
if [ "$out" == "All caught up!" ]; then
    out=""
fi

total="$(printf "%s\n" "$out" | wc -l)"
# Since we always end with a newline (to count the last entry as a line), we always get
# at least 1 as a total here, even if $out is empty. If we didn't use the \n, we'd always
# get 0, even if there was a single line, since it wasn't ended with a newline. To figure
# out whether there really is a line or not when we get a total of 1, we run character
# amount check as well
[ "$total" -eq 1 ] && [ "$(printf "%s" "$out" | wc -c)" -eq 0 ] && total=0

# Only run if we actually found some notifications
if [ "$total" -gt 0 ]; then
    # Since the loop is running in a pipe, it can't modify variables, but we need to know
    # how many notifications were sent, so to ge that information, we store it in a
    # temporary file
    sent_count_file="$(mktemp)"
    printf "0" > "$sent_count_file"

    # Go through each notification, one by one
    printf "%s\n" "$out" | while read -r line; do
        # Parse out the data from given output lines
        issue_type="$(echo "$line" | awk '{print $4}' | sed 's/\x1b\[[0-9;]*m//g')"
        repo_id="$(echo "$line" | awk '{print $3}' | sed 's/\x1b\[[0-9;]*m//g')"


        if [ "$issue_type" == "PullRequest" ]; then
            issue_id="$(echo "$line" | awk '{print $5}' | sed 's/\x1b\[[0-9;]*m//g' | cut -c2-)"
            description="$(echo "$line" | awk '{for (i=6; i<NF; i++) printf $i " "; print $NF}' | sed 's/\x1b\[[0-9;]*m//g')"
            name="$repo_id ($issue_type #$issue_id)"

            url="https://github.com/$repo_id/pull/$issue_id"
        elif [ "$issue_type" == "Issue" ]; then
            issue_id="$(echo "$line" | awk '{print $5}' | sed 's/\x1b\[[0-9;]*m//g' | cut -c2-)"
            description="$(echo "$line" | awk '{for (i=6; i<NF; i++) printf $i " "; print $NF}' | sed 's/\x1b\[[0-9;]*m//g')"
            name="$repo_id ($issue_type #$issue_id)"

            url="https://github.com/$repo_id/issues/$issue_id"
        elif [ "$issue_type" == "Release" ]; then
            # There's no issue ID with github releases, they just have a title
            # this means if the name is the same, they will be treated as the same release
            # and they could end up being ignored, this could be fixed by using github API and
            # searching for that release's commit, but that's too much work here for little benefit
            description="$(echo "$line" | awk '{for (i=5; i<NF; i++) printf $i " "; print $NF}' | sed 's/\x1b\[[0-9;]*m//g')"
            name="$repo_id ($issue_type)"

            # Because we don't know the tag or commit ID, best we can do is use the page for all releases
            # the new release will be the first one there anyway
            url="https://github.com/$repo_id/releases"
        else
            echo "Unknown issue type: '$issue_type'!"
            echo "Can't construct URL, falling back to just repository URL."
            echo "Please report this issue to ItsDrike/dotfiles repository."
            url="https://github.com/$repo_id"
        fi

        [ $VERY_VERBOSE -eq 1 ] && echo "Found notification $name"
        [ $VERY_VERY_VERBOSE -eq 1 ] && echo "Description: $description"
        [ $VERY_VERY_VERBOSE -eq 1 ] && echo "Constructed url: $url"

        # Create hash from the name and description and use it to construct
        # a path to a temporary file
        # To keep this POSIX compliant, we can't use <<< to feed a string to the
        # sum function, so we're using another temporary file which is then removed
        temp_file="$(mktemp)"
        printf "$name$description" > "$temp_file"
        hashsum="$(sum < "$temp_file" | cut -f 1 -d ' ')"
        rm "$temp_file"

        tmpname="/tmp/gh-notification-$hashsum"
        [ $TEMP_SHOW -eq 1 ] && echo "Tempfile: $tmpname"

        # If the temporary file is already present, this notification was already
        # send and we don't want to re-send it

        # Only sent the notification if it wasn't already cached (doesn't have temp file)
        # this avoids resending the same notifications
        if [ ! -e "$tmpname" ] || [ $NO_CACHE -eq 1 ]; then
            if [ $DRY_RUN -eq 1 ]; then
                [ $VERY_VERBOSE -eq 1 ] && echo "Sending notification (dry-run, no actual notification was sent)"
            else
                [ $VERY_VERBOSE -eq 1 ] && echo "Sending notification"
                send_notify "$name" "$description <$url>"
                # Create the tempfile so that in the next run, we won't resend this notification again
                # NOTE: We're storing the name and description into this file to make it easier
                # to figure out what notification the tempfile belongs to, with ~@~ separator
                printf "%s~@~%s" "$name" "$description" > "$tmpname"
            fi
            # Keep track of how many notifications were sent (didn't have a cache file)
            sent="$(cat "$sent_count_file")"
            sent="$(("$sent"+1))"
            printf "%s" "$sent" > "$sent_count_file"
        else
            [ $VERY_VERBOSE -eq 1 ] && echo "Skipping (cached) - notification already sent"
        fi

        # Add a new-line separator on very verbose to group prints from each iteration
        [ $VERY_VERBOSE -eq 1 ] && echo ""
    done

    # Recover amount of sent notifications from the temporary file
    sent="$(cat "$sent_count_file")"
    rm "$sent_count_file"

    if [ $VERBOSE -eq 1 ]; then
        unsent="$(("$total"-"$sent"))"
        if [ "$sent" -eq "$total" ]; then
            echo "Found and sent $total new notifications"
        elif [ "$unsent" -eq "$total" ]; then
            echo "Found $total notifications, all of which were already sent (no new notifications to send)"
        else
            echo "Found $total notifications, of which $sent were new and sent ($unsent were skipped - cached/already sent)"
        fi
    fi
else
    [ $VERBOSE -eq 1 ] && echo "No new notifications"
fi