fzf-file-previewer

#!/usr/bin/env sh
# vim: ft=sh ts=4 sw=4 sts=4 et :

has() {
    # $1: command to test
    command -v "$1" >/dev/null 2>&1
}

which_exe() {
    # $@: list of commands to test
    for cmd in "$@"; do
        if has "$cmd"; then
            echo "$cmd"
            return
        fi
    done
}

fzf_file_previewer() {
    # $1: file to preview

    # In case that the file name starts with a hyphen
    # and command does not support '--' convention
    fpath=$(realpath -- "$1" 2>/dev/null)

    if [ ! -r "$1" ]; then
        printf "\033[1m%s\033[0m\n" "File not readable:" >&2
        printf "%s\n" "$1" >&2
        return 1
    fi

    # Clear possible ueberzugpp image preview
    if [ -S "$UB_SOCK" ] && has ueberzugpp; then
        ueberzugpp cmd -s "$UB_SOCK" -a remove -i fzf-file-preview-ub 2>/dev/null
    fi

    # Preview directories
    if [ -d "$1" ]; then
        if has tree; then
            tree_output=$(tree -N -L 4 -C -- "$1")
            info=$(echo "$tree_output" | tail -n 1)
            printf "\033[1m%s\033[0m\n\n" "$info"
            printf "%s\n" "$tree_output" | head -n -1
        else
            if has find && has wc; then
                num_files=$(find "$fpath" -type f | wc -l)
                num_dirs=$(find "$fpath" -type d | wc -l)
                printf "\033[1m%d directories, %d files\033[0m\n" \
                    "$num_dirs" "$num_files"
            fi
            ls -l --color=always -- "$1"
        fi
        return
    fi

    # Preview regular files
    if [ -f "$1" ]; then
        case "$(file -b --mime -- "$1")" in
            image/*)
                # ueberzugpp is up and fzf is called from wrapper
                if [ -S "$UB_SOCK" ] && has ueberzugpp; then
                    if [ "$((FZF_MARGIN_RIGHT + FZF_MARGIN_LEFT + \
                        FZF_PADDING_RIGHT + FZF_PADDING_LEFT))" -lt \
                        "$FZF_TERM_COLUMNS" ]; then
                        if [ "$FZF_PREVIEW_ORIENTATION" = 'right' ]; then
                            ub_x=$((FZF_TERM_COLUMNS - FZF_PREVIEW_COLUMNS - \
                                FZF_MARGIN_RIGHT - FZF_PADDING_RIGHT - 2))
                        else
                            ub_x=$((FZF_MARGIN_LEFT + FZF_PADDING_LEFT + 2))
                        fi
                    fi
                    if [ "$((FZF_MARGIN_UP + FZF_MARGIN_BOTTOM + \
                        FZF_PADDING_UP + FZF_PADDING_BOTTOM))" -lt \
                        "$FZF_TERM_LINES" ]; then
                        if [ "$FZF_PREVIEW_ORIENTATION" = 'up' ]; then
                            ub_y=$((FZF_TERM_LINES - FZF_HEIGHT + \
                                FZF_MARGIN_TOP + FZF_PADDING_TOP + 1))
                        else
                            ub_y=$((FZF_TERM_LINES - FZF_MARGIN_BOTTOM - \
                                FZF_PADDING_BOTTOM - FZF_PREVIEW_LINES - 1))
                        fi
                    fi
                    if [ -n "$ub_x" ] && [ -n "$ub_y" ]; then
                        ueberzugpp cmd \
                            -s "$UB_SOCK" \
                            -i fzf-file-preview-ub \
                            -a add \
                            -x "$ub_x" \
                            -y "$ub_y" \
                            --max-width "$FZF_PREVIEW_COLUMNS" \
                            --max-height "$((FZF_PREVIEW_LINES - 1))" \
                            -f "$1" 2>/dev/null
                        return
                    fi
                fi

                # Use ASCII image previewers if ueberzugpp not available
                case "$(which_exe chafa imgcat tiv)" in
                    chafa)
                        if [ -n "$TMUX" ]; then
                            chafa -f symbols \
                                -s "$FZF_PREVIEW_COLUMNS"x"$FZF_PREVIEW_LINES" "$fpath"
                        else
                            chafa -s "$FZF_PREVIEW_COLUMNS"x"$FZF_PREVIEW_LINES" "$fpath"
                        fi
                        ;;
                    imgcat)
                        imgcat -H -w "$FZF_PREVIEW_COLUMNS" \
                            -r "$FZF_PREVIEW_LINES" "$fpath"
                        ;;
                    tiv)
                        tiv -w "$FZF_PREVIEW_COLUMNS" -h "$FZF_PREVIEW_LINES" "$fpath"
                        ;;
                    *)
                        echo "No ascii image previewer found, install chafa, imgcat or tiv" >&2
                        ;;
                esac
                ;;

            application/pdf*)
                if has pdftotext; then
                    pdftotext -l 10 -nopgbrk -nodiag -q "$1" -
                    return
                else
                    echo 'pdftotext not found' >&2
                fi
                ;;

            application/zip*)
                if has unzip; then
                    unzip -l "$fpath"
                elif has zip; then
                    zip -sf -- "$1"
                else
                    echo 'unzip and zip not found' >&2
                fi
                ;;

            application/x-tar* | application/gzip*)
                if has tar; then
                    tar --ignore-command-error -tf "$1" 2>/dev/null
                else
                    echo 'tar not found' >&2
                fi
                ;;

            text/html*)
                if has w3m; then
                    w3m -dump "$fpath"
                    return
                elif has html2text; then
                    html2text -- "$1"
                    return
                fi
                ;;

            *)
                # Use glow for markdown files
                case "$1" in
                    *.md)
                        if has glow; then
                            glow_config="${XDG_CONFIG_HOME-$HOME/.config}/glow/glow.yml"
                            if [ -e "$glow_config" ]; then
                                style=$(grep -Po '(?<=style: ")[^"]+' "$glow_config")
                            else
                                style='auto'
                            fi
                            glow -s="$style" -w="$FZF_PREVIEW_COLUMNS" -- "$1"
                            return
                        fi
                        ;;
                esac

                # Use highlight or cat for remaining files
                if has highlight; then
                    highlight_config="$HOME/.highlight/themes/highlight.theme"
                    if [ ! -e "$highlight_config" ]; then
                        highlight -O ansi --force -- "$1"
                    else
                        highlight -O ansi --force --config-file "$highlight_config" -- "$1"
                    fi
                    return
                fi

                if has cat; then
                    cat "$1"
                    return
                fi
                ;;
        esac
    fi
}

fzf_file_previewer "$@"