helix-ext

#!/usr/bin/env bash
#
# Author: Davide Galassi <davxy@datawok.net>
# Version: 0.1.8
#
# Extensions used by Helix editor
#
# Depedencies:
# - `zellij`
# - `ff`: https://github.com/davxy/script-nest/blob/main/bin/ff
# - `fzf` for the `search` subcommand
# - `bat` for the `search --buffer` option
# - `git` for the `git` subcommand
# - `gh` for the `git` subcommand `--browse` option

# Construct a trampoline editor
function make_editor() {
    bin="$EXT_DIR/bin/edit"
    cat > "$bin" <<EOF
#!/usr/bin/env bash
zellij action focus-previous-pane
zellij action write 27
zellij action write-chars ":open \$@"
zellij action write 13
zellij action focus-next-pane
#zellij action write-chars ":q"
#zellij action write 13
EOF
    chmod +x "$bin"
}

# Construct a trampoline xdg_open
function make_xdg_open() {
    bin="$EXT_DIR/bin/xdg-open"
    cat > "$bin" <<EOF
#!/usr/bin/env bash
if [[ -f "\$1" ]]; then
    /tmp/helix-ext/bin/edit "\$1"
else
    /usr/bin/xdg-open "\$1"
fi
EOF
    chmod +x "$bin"
}

function make_ext_dir() {
    mkdir -p "$EXT_DIR/bin"
    make_editor
    make_xdg_open
}

# Opens a list of files.
#
# Input files should be a space separated list of "<name>:<line>"
function open_files() {
    local files=$1
    # Select editor pane
    zellij action focus-previous-pane
    # Write down open command
    # Looks like carriage return is the way to do this (line feed doesn't work)
    zellij action write 27  # ESC
    zellij action write-chars ":open $files"
    zellij action write 13  # CR
    # Move focus back to working pane
    zellij action focus-next-pane
}

# Search some text in helix current buffer
function search_text() {
    local text=$1
    # Select editor pane
    zellij action focus-previous-pane
    # Write down search command
    zellij action write 27  # ESC
    zellij action write-chars "/$text"
    zellij action write 13  # CR
    # Move focus back to working pane
    zellij action focus-next-pane
}

# Saturated subtraction
function saturating_sub() {
    if (( $2 >= $1 )); then
        echo 1
    else
        echo $(( $1 - $2 ))
    fi
}

# Get current file name and line number from the helix status bar.
# Assumes the following helix configuration:
#
# ```toml
# [editor.statusline]
# left = ["mode", "spinner"]
# center = ["file-name"]
# right = ["diagnostics", "selections", "position-percentage", "position"]
# ```
# Doesn't work if the "spinner" is in action...
function current_file_and_line() {
    # Select original pane
    zellij action focus-previous-pane
    # Capture output of the original pane
    zellij action dump-screen "$DUMP_FILE"
    # Back to working pane
    zellij action focus-next-pane

    # Extract status line
    status_line=$(cat $DUMP_FILE | grep -E "(NOR|INS|SEL)")
    rm -f $DUMP_FILE
    # Manage multiple opened windows
    status_line=$(echo $status_line | sed -n -E 's/.*(NOR|INS|SEL)[[:space:]]*(.*)/\1 \2/p')

    filename=$(echo $status_line | cut -d' ' -f2)
    # Try to detect if 'spinner' is present on the line
    # "⣾", "⣽", "⣻", "⢿", "⡿", "⣟", "⣯", "⣷" 
    if [[ "$filename" =~ [⣾⣽⣻⢿⡿⣟⣯⣷] ]]; then
        filename=$(echo $status_line | cut -d' ' -f3)
    fi
    # Expand eventual "~"
    filename=$(eval echo $filename)
    # Fetch line number
    line=$(echo $status_line | rev | cut -d' ' -f1 | rev | cut -d ':' -f1)
    echo "$filename:$line"
}

# Get current file name
function current_file() {
    fl=$(current_file_and_line)
    file=$(echo $fl | cut -d':' -f1)
    echo "$file"
}

# Search in current working directory
# 
# First argument should be any extra option to pass to `ff` script (like "f")
function search_cwd() {
    opts="-xc"
    if [[ $1 = "-f" ]]; then
        opts="${opts}f"
        shift
    fi
    query=""
    if [[ $1 == "-q" && ${#2} != 1 ]]; then
        query="$2"
    fi

    zellij action toggle-fullscreen
    file_paths=$(ff "$opts" -q "$query")
    zellij action toggle-fullscreen

    new_paths=""
    for file in $file_paths; do
        new_paths="${new_paths} ${PWD}/${file}"
    done
    file_paths=$new_paths

    if [[ $file_paths == "" ]]; then
        return 1
    fi

    open_files "$file_paths"
}

# Search in git workspace
function search_ws() {
    wd=$(pwd)
    ws=$(git rev-parse --show-toplevel 2>/dev/null)
    if [ $? -ne 0 ]; then
        echo "Not in a git working directory"; sleep 2; return 1
    fi
    cd $ws
    search_cwd $@
    cd $wd
}

# Seach in current buffer
function search_buf() {
    query=""
    if [[ $1 == "-q" && ${#2} != 1 ]]; then
        query="$2"
    fi

    file=$(current_file)
    if [[ $file == "[scratch]" ]]; then
        echo "Can't search in scratch buffer"; sleep 2; return 1
    fi

    zellij action toggle-fullscreen
    flq="$(ff -vc -q "$query" "$file")"
    zellij action toggle-fullscreen

    fl=$(echo "$flq" | grep "result" | awk '{ print $2 }')
    if [[ "$fl" != "" ]]; then
        open_files "$fl"
        query=$(echo "$flq" | grep "query" | awk '{ print $2}')
        if [[ $query != "" ]]; then
            search_text "$query"
        fi
    fi
}

# Print git status
function git_status() {
    zellij action toggle-fullscreen
    file=$(git status --short | \
         awk '{ printf("[%s] %s\n", $1, $2) }' | \
         fzf --cycle --preview 'git diff --color {2}' --preview-window 'up,~4,+{2}+4/2' | \
         awk '{ print $2 }')
    zellij action toggle-fullscreen
    if [[ $file == "" ]]; then
        return 1
    fi

    open_files "${file}:1"
}

# Print git blame information
function git_blame() {
    fl=$(current_file_and_line)
    file=$(echo $fl | cut -d':' -f1)
    line=$(echo $fl | cut -d':' -f2)
    git ls-files --error-unmatch "$file" 2> /dev/null
    if [ $? -ne 0 ]; then
        echo "Not in a git working directory"; sleep 3; return 1
    fi
    start=$(saturating_sub $line 10)
    git blame -L $start,+100 $file --color-by-age --color-lines
}

# Open current file and line in a browser using `gh` tool
function git_browse() {   
    fl=$(current_file_and_line)
    file=$(echo $fl | cut -d':' -f1) 
    line=$(echo $fl | cut -d':' -f2)
    file_path=$(realpath $file)

    git ls-files --error-unmatch "$file_path" >/dev/null 2>&1
    if [ $? -ne 0 ]; then
        # Not versioned file. Open the repo root
        fl=""
    else
        git_root=$(git rev-parse --show-toplevel)
        fl="${file_path#$git_root/}:$line"
    fi

    branch=$(git symbolic-ref --short HEAD)

    remote=$(git config --get branch.${branch}.remote)
    if [[ $remote == "" ]]; then
        echo "Warning no 'remote' associated to track branch '$branch'."
        echo "Available remotes:"
        git remote -v | awk '{ 
            if ($3 == "(fetch)") {
                printf("  - \"%s\": %s\n", $1, $2) }
            }
        '
        echo "Fix with: 'git branch --set-upstream-to=origin/main $branch'."
        read -p "Enter remote to use [origin]: " remote
        remote=${remote:-origin}
    fi

    remote_url=$(git remote get-url $remote)
    if [[ $remote_url == "" ]]; then
        echo "No remote url for $remote"
        sleep 3
        return 1
    fi

    gh browse "$fl" -b "$branch" -R "$remote_url"
    # Necessary sleep...
    sleep 3
}

# Open markdown file table of contents
function markdown_toc() {
    file=$(current_file)
    zellij action toggle-fullscreen
    choice=$(cat $file | grep -n "^#" | sed 's/#/  /g' | awk -F':' '{printf("%4s - %s\n", $1, $2)}' | fzf --no-sort --exact --cycle --layout=reverse --header="'$file' TOC")
    zellij action toggle-fullscreen
    line=$(echo $choice | cut -d' ' -f1)
    if [[ "$line" != "" ]]; then
        open_files "$file:$line"
    fi
}

# Diff current buffer with the one in the disk
function diff_with_saved() {
    fl=$(current_file_and_line)
    file=$(echo $fl | cut -d':' -f1)
    line=$(echo $fl | cut -d':' -f2)

    # Select original pane
    zellij action focus-previous-pane

    # Save buffer to a temporary file by copying buffer content to a scratch
    # buffer and saving it to DUMP_FILE (this will left untouched the current
    # buffer, with its pending changes as well)
    zellij action write-chars "%y"
    zellij action write-chars "${line}G"
    zellij action write-chars ":new"
    zellij action write 13
    zellij action write-chars "p"
    # Remove first empty line
    zellij action write-chars "ggd"
    # Write temporary buffer in DUMP_FILE
    zellij action write-chars ":write! $DUMP_FILE"
    zellij action write 13
    # Close temporary file buffer
    zellij action write-chars ":buffer-close"
    zellij action write 13

    # Back to working pane
    zellij action focus-next-pane

    if command -v delta &> /dev/null; then
        delta --paging always $file $DUMP_FILE
    else
        diff -u --color $file $DUMP_FILE | bat --plain --paging always
    fi

    rm -f $DUMP_FILE
}

# Resize a pane
function resize_pane() {
    counter=1
    while [ $counter -le 3 ]; do
        zellij action resize decrease
        ((counter++))
    done
}

# Open gitui pane
function gitui_pane() {
    if [ -e $GITUI_FILE ]; then
        return 1
    fi
    zellij action rename-pane "gitui"

    touch $GITUI_FILE
    GIT_EDITOR="$EXT_DIR/bin/edit" gitui
    rm -f $GITUI_FILE
}

# Open broot pane
function tree_pane() {
    if [ -e $BROOT_FILE ]; then
        return 1
    fi
    zellij action rename-pane "broot"

    file=$(current_file)
    if [[ $file == "[scratch]" ]]; then
        file=
    fi
    dir=$(dirname "$file")

    touch $BROOT_FILE
    EDITOR="$EXT_DIR/bin/edit" broot "$dir"
    rm -f $BROOT_FILE

    
}

# Change directory
function change_dir() {
    file=$(current_file)
    dir=$(dirname "$file")

    # Select original pane
    zellij action focus-previous-pane

    # Save buffer to a temporary file by copying buffer content to a scratch
    # buffer and saving it to DUMP_FILE (this will left untouched the current
    # buffer, with its pending changes as well)
    zellij action write-chars ":cd ${dir}"
    zellij action write 13
    # Back to working pane
    zellij action focus-next-pane
}

# Open terminal pane
function term_pane() {
    if [ -e $TERM_FILE ]; then
        return 1
    fi
    zellij action rename-pane "term"

    touch $TERM_FILE
    EDITOR="$EXT_DIR/bin/edit" /bin/bash
    rm -f $TERM_FILE
}

# Print help and sleep $1 seconds
function help() {
    echo "Usage: helix-ext <command> [options]"
    echo ""
    echo "Commands:"
    echo "- 'search'"
    echo "   -b, --buffer: search in current buffer content"
    echo "   -c, --current: search in current working directory"
    echo "   -C, --current-inc-path: search in current working directory (include path)"
    echo "   -w, --workspace: search in git workspace (requires to be in a git repo)"
    echo "   -W, --workspace-inc-path: search in git workspace (include path)"
    echo "- 'git'"
    echo "   -u, --ui: git-ui"
    echo "   -s, --status: print working dir status"
    echo "   -b, --blame: print blame info for current file"
    echo "   -B, --browse: browse remote repo at current file and line"
    echo "- 'markdown'"
    echo "   - t, --toc: table of contents"
    echo "- 'diff': diff buffer unsaved modifications with backing file"
    echo "- 'tree': open file tree (broot)"
    echo "- 'term': open terminal"
    echo "- 'clean': cleanup helix instance data"
    sleep $1
    exit 1
}

EXT_DIR="/tmp/helix-ext"
if [ ! -d "$EXT_DIR" ]; then
    make_ext_dir
fi

CANARY_FILE="${EXT_DIR}/canary"

if [ ! -e "$CANARY_FILE" ]; then
    # Be sure the parent process is Helix
    # Get the parent process ID (PPID) of the current process
    parent_pid=$PPID
    # Get the name of the parent process using the PPID
    parent_name=$(ps -o comm= -p "$parent_pid")
    if [[ $parent_name != "helix" && $parent_name != "hx" ]]; then 
        echo "This script should be called from Helix (got $parent_name)"
        exit
    fi
    # Save the helix process instance pid in CANARY_FILE (to get it later)
    echo $PPID > "$CANARY_FILE"

    direction="down"
    if [[ $1 == "tree" ]]; then
        direction="right"
    fi

    read userinput

    # Re-execute the script in a working pane
    zellij action rename-pane "helix"
    exec zellij run -c -n "helix-ext" -d $direction -- helix-ext $@ "$userinput"
fi

# TODO: testing if improves reliability
sleep 0.1

# Remove the canary file
helix_pid=$(cat $CANARY_FILE)
rm $CANARY_FILE

INSTANCE_DIR="${EXT_DIR}/${helix_pid}"
mkdir -p ${INSTANCE_DIR}

DUMP_FILE="${INSTANCE_DIR}/dump" 
BROOT_FILE="${INSTANCE_DIR}/broot"
GITUI_FILE="${INSTANCE_DIR}/gitui"
TERM_FILE="${INSTANCE_DIR}/term"

direction="down"
if [[ $1 == "tree" ]]; then
    direction="right"
fi
resize_pane $direction

# # Check if this is the first helix-ext program for this helix instance
# if [ -z "$(ls -A ${INSTANCE_DIR})" ]; then
#     zellij action toggle-pane-frames
# fi

# Create a tag file for the program
touch "${INSTANCE_DIR}/$$"

# Default to custom bins (xdg-open)
export PATH="$EXT_DIR/bin:$PATH"

case "$1" in
    "cd")
        case $2 in
            "-c"|"--current")
                change_dir
                ;;
            "*")
                help 3
        esac
        ;;
    "search") 
        case $2 in
            "-b"|"--buffer")
                search_buf -q "$3"
                ;;
            "-c"|"--current")
                search_cwd -q "$3"
                ;;
            "-C"|"--current-inc-path")
                search_cwd -f -q "$3"
                ;;
            "-w"|"--workspace")
                search_ws -q "$3"
                ;;
            "-W"|"--workspace-inc-path")
                search_ws -f -q "$3"
                ;;
            "*")
                help 3
        esac
        ;;
    "git")
        case $2 in
            "-u"|"--ui")
                gitui_pane
                ;;
            "-s"|"--status")
                git_status
                ;;
            "-b"|"--blame")
                git_blame
                ;;
            "-B"|"--browse")
                git_browse
                ;;
            "*")
                help 3
        esac
        ;;
    "markdown")
        case $2 in
            "-t"|"--toc")
                markdown_toc
                ;;
            "*")
                help 3
        esac
        ;;
    "diff")
        diff_with_saved
        ;;
    "tree")
        tree_pane
        ;;
    "term")
        term_pane
        ;;
    "clean")
        echo "Removing all helix-ext data for current instance ($helix_pid)"
        sleep 2
        rm -rf $INSTANCE_DIR
        ;;
    *)
        help 3
        ;;
esac

# Remove helix-ext instance file
rm -f "${INSTANCE_DIR}/$$"
# # Check if this is the last helix-ext instance program
# if [ -z "$(ls -A ${INSTANCE_DIR})" ]; then
#     zellij action toggle-pane-frames
# fi

# Remove instance folder (if empty)
rmdir --ignore-fail-on-non-empty "$INSTANCE_DIR"

# Close working pane
zellij action close-pane