gh-shell

#!/usr/bin/env bash
set -eo pipefail

usage () {
    echo "AVAILABLE COMMANDS"
    echo "  list:    View your saved shell commands"
    echo "  add:     Add a shell command to your list"
    echo "  remove:  Remove a shell command from your list"
    echo "  restore: Append all commands from your list so your current shell's history file"
    echo ""
    echo "EXAMPLES"
    echo "$ gh shell list"
    echo "$ gh shell add <command>"
    echo "$ gh shell remove <command>"
    echo "$ gh shell restore"
}

get_gist_id () {
    gh api gists -q 'map(select(.files | has("gh-shell")))[0].id'
}

read_gist () {
    gh gist view -f gh-shell $1
}

list () {
    id=$(get_gist_id)
    if [[ -z "$id" ]]; then
        echo "You don't have any commands saved. Try adding one with 'gh shell add <command>'."
        exit 1
    fi

    output=$(read_gist $id)
    if [[ -z "$output" ]]; then
        echo "You don't have any commands saved. Try adding one with 'gh shell add <command>'."
        exit 1
    fi

    echo "$output"
}

create_gist () {
    command=$*
    echo "$command" | gh gist create -d "Saved commands for gh-shell" -f gh-shell - &>/dev/null
}

delete_gist () {
    gh gist delete $1
}

update_gist () {
    id=$1
    shift
    content=$*

    jq --arg c "$content" -n '{"files":{"gh-shell":{"content":$c}}}' \
        | gh api gists/$id -X PATCH -H 'Accept: application/vnd.github.v3+json' --input - \
        &>/dev/null
}

add () {
    shift
    command="$*"
    if [[ -z "$command" ]]; then
        echo "No command specified to add."
        echo ""
        usage
        exit 1
    fi

    id=$(get_gist_id)
    if [[ -z "$id" ]]; then
        create_gist $command
    else
        content=$(read_gist $id)
        content=$(echo -e "$content\n$command")
        update_gist $id "$content"
    fi
}

remove () {
    shift
    command="$*"
    if [[ -z "$command" ]]; then
        echo "No command specified to remove."
        echo ""
        usage
        exit 1
    fi

    id=$(get_gist_id)
    if [[ -z "$id" ]]; then
        # List doesn't exist. Nothing to remove.
        exit 0
    else
        content=$(read_gist $id)
        set +e
        content=$(echo "$content" | grep -Fxv "$command")
        set -e
        if [[ -z "$content" ]]; then
            # When the last command is removed, delete the whole gist
            delete_gist $id
        else
            update_gist $id "$content"
        fi
    fi
}

restore () {
    # When invoked through `gh` directly in a shell, the process chain should look something like
    # (shell) -> gh shell restore -> bash -> gh-shell
    # $PPID will point to the process id of `gh shell restore`. We need to find the parent
    # of this process to determine which shell the user is invoking this from so that we
    # can update the correct history file for that shell.
    parent_shell_pid=$(ps -o ppid= -p $PPID | tr -d '[:space:]')
    parent_shell=$(ps -p $parent_shell_pid -o comm=)
    case $parent_shell in
    *zsh) 
        echo "✅ Detected zsh"
        file=${HISTFILE:-$HOME/.zsh_history}
    ;;
    *bash)
        echo "✅ Detected bash"
        file=${HISTFILE:-$HOME/.bash_history}
    ;;
    *)
        echo "⚠️ Could not detect shell ($parent_shell). Assuming bash."
        file=${HISTFILE:-$HOME/.bash_history}
    esac
    
    echo "$(list)" >> $file
    echo "History file $file updated"

    case $parent_shell in
    *zsh)
        if [[ -z "$TERM_SESSION_ID" ]]; then
            echo "Open a new shell or refresh history in the current shell by running 'fc -RI'"
        else
            # Special case for running in an Apple Terminal instance, which by default captures
            # terminal session history separately and merges from the shared history on launch
            echo "Open a new Terminal instance to refresh history"
        fi
    ;;
    *)
        echo "Open a new shell or refresh history in the current shell by running 'history -n'"
    esac
}

declare -A COMMANDS=(
    [usage]=usage
    [list]=list
    [add]=add
    [remove]=remove
    [restore]=restore
)

"${COMMANDS[${1:-usage}]:-${COMMANDS[usage]}}" "$@"