#!/bin/sh

#using PID for dirname in case multiple instances are opened they do not interfere
CACHEDIR="$HOME/.cache/mangaterm"
TMPDIR="$CACHEDIR/$$"

# read_char var
# from: https://stackoverflow.com/a/30022297
read_char() {
    stty -icanon -echo
    eval "$1=\$(dd bs=1 count=1 2>/dev/null)"
    stty icanon echo
}

help() {
    echo "Read manga/comics/pdfs in the terminal"
    echo "    mangaterm.sh DIRECTORY"
    echo "    mangaterm.sh FILE"
    echo ""
    echo "    --help   show this help menu" 
    echo ""
    echo "keybindings:"
    echo "    j -> next page"
    echo "    k -> previous page"
    echo "    q -> quit"
    echo ""
    exit
}

disp() {
    FILE="$DIR"/"$(echo "$FILES" | head -n "$1" | tail -n 1)" 
    clear
    [ -f "$FILE" ] && chafa -C on "$FILE"

    printf "%s" "$FILE"
}

close() {
    rm -rf "$TMPDIR"
    clear
    exit
}

readDir() {
    DIR="$(echo "$1" | xargs)"

    #if opening an archive that created a subdirectory, open subdirectories until there are multiple files
    SDIR="$(ls -A "$DIR")"
    if [ "$(echo "$SDIR" | wc -l)" = "1" ]; then
        if [ -d "$DIR/$SDIR" ]; then  
            readDir "$DIR"/"$SDIR" 
        fi
    fi

    FILES="$(ls "$DIR")"
    LEN="$(echo "$FILES" | wc -l)"

    disp "1"

    I=1
    while read_char char; do
        if [ "$char" = "j" ]; then
                I=$((I + 1))
            elif [ "$char" = "k" ]; then
                I=$((I - 1))
            elif [ "$char" = "q" ]; then
                close
            fi

        if [ "$I" -ge "$LEN" ] || [ "$I" -le "0" ]; then
            if [ "$I" -ge "$LEN" ]; then
                I="$LEN"
            elif [ "$I" -le "0" ]; then
                I=0
            fi 
        fi

        disp "$I" 
    done

    close
}

handleFile() {
    case $(file --mime-type "$1" -b) in
        inode/directory) readDir "$1" ;; 
        application/zip) unzip "$1" -d "$TMPDIR" && readDir "$TMPDIR" ;; 
        application/*rar) 7z x "$1" -o"$TMPDIR" && readDir "$TMPDIR" ;;
        application/gzip) tar xzvf "$1" --directory="$TMPDIR" && readDir "$TMPDIR" ;;
        application/pdf) pdftoppm -jpeg "$1" "$TMPDIR"/page && readDir "$TMPDIR" ;;
        *) help ;;

    esac
}

trap 'close' 2
trap 'close' 15 

[ "$1" = "--help" ] && help

mkdir -p "$TMPDIR"

if [ "$(echo "$1" | cut -c1-1)" = "-" ]; then
   foot -e mangaterm "$2" 2>/dev/null > /dev/null
fi

handleFile "$1"