#!/usr/bin/env bash

set -o noclobber -o noglob -o nounset -o pipefail
IFS=$'\n'

## Meanings of exit codes:
## code | meaning    | action of ranger
## -----+------------+-------------------------------------------
## 0    | success    | Display stdout as preview
## 1    | no preview | Display no preview at all
## 2    | plain text | Display the plain content of the file
## 3    | fix width  | Don't reload when width changes
## 4    | fix height | Don't reload when height changes
## 5    | fix both   | Don't ever reload
## 6    | image      | Display the image `$IMAGE_CACHE_PATH` points to as an image preview
## 7    | image      | Display the file directly as an image

# Script arguments
FILE_PATH="${1}"         # Full path of the highlighted file
PV_WIDTH="${2}"          # Width of the preview pane (number of fitting characters)

# shellcheck disable=SC2034 # PV_HEIGHT is provided for convenience and unused

PV_HEIGHT="${3}"         # Height of the preview pane (number of fitting characters)

# Full path that should be used to cache image preview
IMAGE_CACHE_PATH="$4"
PV_IMAGE_ENABLED="${5}"  # 'True' if image previews are enabled, 'False' otherwise.

FILE_EXTENSION="${FILE_PATH##*.}"
FILE_EXTENSION_LOWER="$(printf "%s" "${FILE_EXTENSION}" | tr '[:upper:]' '[:lower:]')"

HIGHLIGHT_SIZE_MAX=262143  # 256KiB
HIGHLIGHT_TABWIDTH=${HIGHLIGHT_TABWIDTH:-8}
HIGHLIGHT_STYLE=${HIGHLIGHT_STYLE:-pablo}
HIGHLIGHT_OPTIONS="--replace-tabs=${HIGHLIGHT_TABWIDTH} --style=${HIGHLIGHT_STYLE} ${HIGHLIGHT_OPTIONS:-}"
PYGMENTIZE_STYLE=${PYGMENTIZE_STYLE:-autumn}
OPENSCAD_IMGSIZE=${RNGR_OPENSCAD_IMGSIZE:-1000,1000}
OPENSCAD_COLORSCHEME=${RNGR_OPENSCAD_COLORSCHEME:-Tomorrow Night}

handle_extension() {
    case "${FILE_EXTENSION_LOWER}" in
        # DO NOTHING
        crypt|flac|mp3|opus|aac|iso|img|bk)
            exit 1
            ;;
        # ## Archive
        # a|ace|alz|arc|arj|bz|bz2|cab|cpio|deb|gz|jar|lha|lz|lzh|lzma|lzo|\
        # rpm|rz|t7z|tar|tbz|tbz2|tgz|tlz|txz|tZ|tzo|war|xpi|xz|Z|zip)
        #     atool --list -- "${FILE_PATH}" && exit 5
        #     bsdtar --list --file "${FILE_PATH}" && exit 5
        #     exit 1;;
        # rar)
        #     ## Avoid password prompt by providing empty password
        #     unrar lt -p- -- "${FILE_PATH}" && exit 5
        #     exit 1;;
        # 7z)
        #     ## Avoid password prompt by providing empty password
        #     7z l -p -- "${FILE_PATH}" && exit 5
        #     exit 1;;

        pdf)
            ## Preview as text conversion
            mutool draw -F txt -i -- "${FILE_PATH}" 1-10 | \
              fmt -w "${PV_WIDTH}" && exit 5
            exit 1;;

        odt|ods|odp|sxw)
        #     ## Preview as text conversion
        #     odt2txt "${FILE_PATH}" && exit 5
            pandoc -s -t markdown -- "${FILE_PATH}" && exit 5
            exit 1;;

        ## XLSX
        xlsx)
            ## Preview as csv conversion
            ## Uses: https://github.com/dilshod/xlsx2csv
            xlsx2csv -- "${FILE_PATH}" && exit 5
            exit 1;;

        ## HTML
        htm|html|xhtml)
            ## Preview as text conversion
            w3m -dump "${FILE_PATH}" && exit 5
            pandoc -s -t markdown -- "${FILE_PATH}" && exit 5
            ;;

        ## JSON
        json)
            jq --color-output . "${FILE_PATH}" && exit 5
            python -m json.tool -- "${FILE_PATH}" && exit 5
            ;;

        ## Direct Stream Digital/Transfer (DSDIFF) and wavpack aren't detected
        ## by file(1).
        dff|dsf|wv|wvc)
            mediainfo "${FILE_PATH}" && exit 5
            exiftool "${FILE_PATH}" && exit 5
            ;; # Continue with next handler on failure
    esac
}

handle_image() {
    ## Size of the preview if there are multiple options or it has to be
    ## rendered from vector graphics. If the conversion program allows
    ## specifying only one dimension while keeping the aspect ratio, the width
    ## will be used.
    local DEFAULT_SIZE="1920x1080"

    local mimetype="${1}"
    case "${mimetype}" in
        image/*)
            local orientation
            orientation="$( identify -format '%[EXIF:Orientation]\n' -- "${FILE_PATH}" )"
            ## If orientation data is present and the image actually
            ## needs rotating ("1" means no rotation)...
            if [[ -n "$orientation" && "$orientation" != 1 ]]; then
                ## ...auto-rotate the image according to the EXIF data.
                convert -- "${FILE_PATH}" -auto-orient "${IMAGE_CACHE_PATH}" && exit 6
            fi
            exit 7;;

        video/*)
            ffmpegthumbnailer -i "${FILE_PATH}" -o "${IMAGE_CACHE_PATH}" -s 0 -q 3 -c jpeg && exit 6
            exit 1
            ;;

        ## PDF
        # application/pdf)
        #     pdftoppm -f 1 -l 1 \
        #              -scale-to-x "${DEFAULT_SIZE%x*}" \
        #              -scale-to-y -1 \
        #              -singlefile \
        #              -jpeg -tiffcompression jpeg \
        #              -- "${FILE_PATH}" "${IMAGE_CACHE_PATH%.*}" \
        #         && exit 6 || exit 1;;

        ## ePub, MOBI, FB2 (using Calibre)
        # application/epub+zip|application/x-mobipocket-ebook|\
        # application/x-fictionbook+xml)
        #     # ePub (using https://github.com/marianosimone/epub-thumbnailer)
        #     epub-thumbnailer "${FILE_PATH}" "${IMAGE_CACHE_PATH}" \
        #         "${DEFAULT_SIZE%x*}" && exit 6
        #     ebook-meta --get-cover="${IMAGE_CACHE_PATH}" -- "${FILE_PATH}" \
        #         >/dev/null && exit 6
        #     exit 1;;

        # Font
        # application/font*|application/*opentype)
        #     preview_png="/tmp/$(basename "${IMAGE_CACHE_PATH%.*}").png"
        #     if fontimage -o "${preview_png}" \
        #                  --pixelsize "120" \
        #                  --fontname \
        #                  --pixelsize "80" \
        #                  --text "  ABCDEFGHIJKLMNOPQRSTUVWXYZ  " \
        #                  --text "  abcdefghijklmnopqrstuvwxyz  " \
        #                  --text "  0123456789.:,;(*!?') ff fl fi ffi ffl  " \
        #                  --text "  The quick brown fox jumps over the lazy dog.  " \
        #                  "${FILE_PATH}";
        #     then
        #         convert -- "${preview_png}" "${IMAGE_CACHE_PATH}" \
        #             && rm "${preview_png}" \
        #             && exit 6
        #     else
        #         exit 1
        #     fi
            # ;;

        ## Preview archives using the first image inside.
        # (Very useful for comic book collections for example.)
         application/zip|application/x-rar|application/x-7z-compressed|\
             application/x-xz|application/x-bzip2|application/x-gzip|application/x-tar)
             local fn=""; local fe=""
             local zip=""; local rar=""; local tar=""; local bsd=""
             case "${mimetype}" in
                 application/zip) zip=1 ;;
                 application/x-rar) rar=1 ;;
                 application/x-7z-compressed) ;;
                 *) tar=1 ;;
             esac
             { [ "$tar" ] && fn=$(tar --list --file "${FILE_PATH}"); } || \
             { fn=$(bsdtar --list --file "${FILE_PATH}") && bsd=1 && tar=""; } || \
             { [ "$rar" ] && fn=$(unrar lb -p- -- "${FILE_PATH}"); } || \
             { [ "$zip" ] && fn=$(zipinfo -1 -- "${FILE_PATH}"); } || return

             fn=$(echo "$fn" | python -c "import sys; import mimetypes as m; \
                     [ print(l, end='') for l in sys.stdin if \
                       (m.guess_type(l[:-1])[0] or '').startswith('image/') ]" |\
                 sort -V | head -n 1)
             [ "$fn" = "" ] && return
             [ "$bsd" ] && fn=$(printf '%b' "$fn")

             [ "$tar" ] && tar --extract --to-stdout \
                 --file "${FILE_PATH}" -- "$fn" > "${IMAGE_CACHE_PATH}" && exit 6
             fe=$(echo -n "$fn" | sed 's/[][*?\]/\\\0/g')
             [ "$bsd" ] && bsdtar --extract --to-stdout \
                 --file "${FILE_PATH}" -- "$fe" > "${IMAGE_CACHE_PATH}" && exit 6
             [ "$bsd" ] || [ "$tar" ] && rm -- "${IMAGE_CACHE_PATH}"
             [ "$rar" ] && unrar p -p- -inul -- "${FILE_PATH}" "$fn" > \
                 "${IMAGE_CACHE_PATH}" && exit 6
             [ "$zip" ] && unzip -pP "" -- "${FILE_PATH}" "$fe" > \
                 "${IMAGE_CACHE_PATH}" && exit 6
             [ "$rar" ] || [ "$zip" ] && rm -- "${IMAGE_CACHE_PATH}"
             ;;
    esac
}

handle_mime() {
    local mimetype="${1}"
    case "${mimetype}" in
        text/* | */xml | *script)
            ## Syntax highlight
            cat "$FILE_PATH" && exit 5
            exit 2;;
    esac
}

handle_fallback() {
    echo '----- File Type Classification -----' && file --dereference --brief -- "${FILE_PATH}" && exit 5
    exit 1
}

# do nothing if > 50mb
size="$(du -k "${FILE_PATH}" | sed 's/\t.*//g')"
[ "$size" -le 20480 ] || exit 1

handle_extension

MIMETYPE="$( file --dereference --brief --mime-type -- "${FILE_PATH}" )"
if [ "${PV_IMAGE_ENABLED}" = True ]; then
    handle_image "${MIMETYPE}"
fi
handle_mime "${MIMETYPE}"
handle_fallback
