#!/usr/bin/env sh

# Description: Preview plugin for nnn's built-in preview pane
# Auto-detected from plugins dir
# Usage: .npreview <filepath> <width> <height>
# All dependencies optional — graceful fallback to head/file/strings

set -euf

F="$1"
W="${2:-80}"
H="${3:-25}"
ext="${F##*.}"
ext="$(printf "%s" "$ext" | tr '[:upper:]' '[:lower:]')"

has() { type "$1" >/dev/null 2>&1; }
hd() { head -n "$H"; }

# --- Handlers ---

show_dir() {
    has tree && { tree -L 1 -n --dirsfirst --noreport "$F" | hd; return; }
    find "$F" -maxdepth 1 -print 2>/dev/null | hd
}

show_text() {
    has bat && { bat --style=plain --color=never --paging=never --line-range=":${H}" -- "$F" 2>/dev/null; return; }
    has batcat && { batcat --style=plain --color=never --paging=never --line-range=":${H}" -- "$F" 2>/dev/null; return; }
    head -n "$H" "$F"
}

show_pdf() {
    has pdftotext && { pdftotext -l 1 -nopgbrk -q -- "$F" - 2>/dev/null | hd; return; }
    has mutool && { mutool draw -F txt -i -- "$F" 1 2>/dev/null | hd; return; }
    show_meta
}

show_archive() {
    case "$ext" in
        rar) has unrar && { unrar lt -p- -- "$F" 2>/dev/null | hd; return; } ;;
        7z)  has 7z && { 7z l -p -- "$F" 2>/dev/null | hd; return; } ;;
    esac
    has atool && { atool --list -- "$F" 2>/dev/null | hd; return; }
    has bsdtar && { bsdtar --list --file "$F" 2>/dev/null | hd; return; }
    has tar && { tar tf "$F" 2>/dev/null | hd; return; }
    has unzip && [ "$ext" = "zip" ] && { unzip -l "$F" 2>/dev/null | hd; return; }
    printf "[archive %s]\n" "$(du -h "$F" 2>/dev/null | cut -f1)"
}

show_image() {
    has img2txt && { img2txt --gamma=0.6 --width="$W" -- "$F" 2>/dev/null | hd; return; }
    show_meta
}

show_meta() {
    has exiftool && { exiftool "$F" 2>/dev/null | hd; return; }
    has mediainfo && { mediainfo "$F" 2>/dev/null | hd; return; }
    has file && { file -b "$F"; return; }
    printf "[no metadata tool]\n"
}

show_json() {
    has jq && { head -c 65536 "$F" | jq --monochrome-output . 2>/dev/null | hd; return; }
    has python3 && { head -c 65536 "$F" | python3 -m json.tool 2>/dev/null | hd; return; }
    show_text
}

show_md() {
    has glow && { glow -s notty "$F" 2>/dev/null | hd; return; }
    has lowdown && { lowdown -Tterm "$F" 2>/dev/null | hd; return; }
    show_text
}

show_html() {
    has w3m && { w3m -dump "$F" 2>/dev/null | hd; return; }
    has lynx && { lynx -dump -- "$F" 2>/dev/null | hd; return; }
    show_text
}

show_elf() {
    has readelf && { readelf -h "$F" 2>/dev/null | hd; return; }
    has objdump && { objdump -f "$F" 2>/dev/null | hd; return; }
    has file && file -b "$F"
}

show_doc() {
    has odt2txt && { odt2txt "$F" 2>/dev/null | hd; return; }
    show_meta
}

show_bin() {
    has strings && { printf "[binary]\n"; strings "$F" 2>/dev/null | hd; return; }
    printf "[binary %s]\n" "$(du -h "$F" 2>/dev/null | cut -f1)"
}

# --- Directory ---
[ -d "$F" ] && { show_dir; exit 0; }

# --- Dispatch by extension ---
case "$ext" in
    a|ace|alz|arc|arj|bz|bz2|cab|cpio|deb|gz|jar|lha|lz|lzh|lzma|lzo|\
    rpm|rz|t7z|tar|tbz|tbz2|tgz|tlz|txz|tz|tzo|war|xpi|xz|z|zip|rar|7z|zst)
        show_archive; exit 0 ;;
    pdf) show_pdf; exit 0 ;;
    md|mkd|markdown) show_md; exit 0 ;;
    htm|html|xhtml) show_html; exit 0 ;;
    json) show_json; exit 0 ;;
    odt|ods|odp|sxw) show_doc; exit 0 ;;
    torrent) has transmission-show && { transmission-show -- "$F" 2>/dev/null | hd; exit 0; } ;;
    sqlite|sqlite3|db) has sqlite3 && { printf ".tables\n" | sqlite3 "$F" 2>/dev/null | hd; exit 0; } ;;
    o|so|dylib) show_elf; exit 0 ;;
    c|cc|cpp|h|hpp|rs|go|py|rb|js|ts|java|sh|bash|zsh|pl|lua|vim|el|\
    css|scss|yaml|yml|toml|ini|conf|xml|sql|diff|patch|awk|sed|make)
        show_text; exit 0 ;;
esac

# --- Dispatch by mime type ---
has file || { show_text; exit 0; }
mime="$(file -bL --mime-type -- "$F" 2>/dev/null)"

case "$mime" in
    text/*|*/xml) show_text ;;
    application/json) show_json ;;
    application/pdf) show_pdf ;;
    application/zip|application/x-tar|application/x-rar*|\
    application/x-7z*|application/x-bzip*|application/x-xz|\
    application/x-compress*|application/gzip|application/zstd)
        show_archive ;;
    image/*) show_image ;;
    audio/*|video/*) show_meta ;;
    application/x-executable|application/x-sharedlib|application/x-pie-executable|\
    application/x-object) show_elf ;;
    application/vnd.openxmlformats*|application/vnd.oasis.opendocument*) show_doc ;;
    *) show_bin ;;
esac