powerline-shell.bash

#!/usr/bin/env bash

__ps_main() {
  readonly __ps_branch_indicator='⎇'
  readonly __ps_clean_indicator='✓'
  readonly __ps_dirty_indicator='✗'
  readonly __ps_staged_indicator='+'
  readonly __ps_unstaged_indicator='-'
  readonly __ps_untracked_indicator='?'
  readonly __ps_stash_indicator='¢'
  readonly __ps_pull_indicator='⇣'
  readonly __ps_push_indicator='⇡'

  readonly __ps_color_fg_base="\\[$(tput setaf 0)\\]"
  readonly __ps_color_bg_base="\\[$(tput setab 7)\\]"
  readonly __ps_color_bg_exit_nonzero="\\[$(tput setab 1)\\]"
  readonly __ps_color_bg_exit_zero="\\[$(tput setab 2)\\]"
  readonly __ps_color_bg_git="\\[$(tput setab 7)\\]"
  readonly __ps_color_reset="\\[$(tput sgr0)\\]"

  __ps_repository_status() {
    hash git 2>/dev/null || return

    local -r branch=$(git symbolic-ref --short HEAD 2>/dev/null || git describe --tags --always 2>/dev/null)

    [[ -n "${branch}" ]] || return

    local -r git_status=$(git status --porcelain)
    if [[ -z "${git_status}" ]]; then
      local status_indicators="${__ps_clean_indicator}"
    else
      local status_indicators="${__ps_dirty_indicator}"
    fi

    local -r staged_files=$(echo "${git_status}" | grep -cE '^[A-Z]' | grep -Eo '\d+')
    [[ "${staged_files}" -gt 0 ]] 2>/dev/null && status_indicators+=" ${__ps_staged_indicator}${staged_files}"

    local -r unstaged_files=$(echo "${git_status}" | grep -cE '^.[A-Z]' | grep -Eo '\d+')
    [[ "${unstaged_files}" -gt 0 ]] 2>/dev/null && status_indicators+=" ${__ps_unstaged_indicator}${unstaged_files}"

    local -r untracked_files=$(echo "${git_status}" | grep -cE '^\?\?' | grep -Eo '\d+')
    [[ "${untracked_files}" -gt 0 ]] 2>/dev/null && status_indicators+=" ${__ps_untracked_indicator}${untracked_files}"
    
    local -r stash_items=$(git stash list | wc -l | grep -Eo '\d+')
    [[ "${stash_items}" -gt 0 ]] 2>/dev/null && status_indicators+=" ${__ps_stash_indicator}${stash_items}"
    
    local -r git_status_branch=$(git status --porcelain --branch)
    
    local -r commits_behind=$(echo "${git_status_branch}" | grep -E '^##' | grep -Eo 'behind \d+' | grep -Eo '\d+')
    [[ -n "${commits_behind}" ]] && status_indicators+=" ${__ps_pull_indicator}${commits_behind}"

    local -r commits_ahead=$(echo "${git_status_branch}" | grep -E '^##' | grep -Eo 'ahead \d+' | grep -Eo '\d+')
    [[ -n "${commits_ahead}" ]] && status_indicators+=" ${__ps_push_indicator}${commits_ahead}"

    printf '%s  %s %s ' "${__ps_branch_indicator}"  "${branch}" "${status_indicators}"
  }

  __ps_ps1() {
    # shellcheck disable=SC2181
    if [[ $? -eq 0 ]]; then
      PS1="${__ps_color_bg_exit_zero} "
    else
      PS1="${__ps_color_bg_exit_nonzero} "
    fi

    PS1+="${__ps_color_reset}${__ps_color_bg_base}${__ps_color_fg_base} "

    local -r prefix=$(git rev-parse --show-prefix 2>/dev/null)
    local -r toplevel=$(git rev-parse --show-toplevel 2>/dev/null)
    local -r git_dir=$(git rev-parse --git-dir 2>/dev/null)
    if [[ -n "$prefix" ]]; then
      PS1+="$(basename "$toplevel")/${prefix%/}"
    elif [[ -d "$git_dir" && "$toplevel" = "$(pwd)" ]]; then
      PS1+="\\W"
    else
      PS1+="\\w"
    fi

    PS1+=" ${__ps_color_reset}${__ps_color_bg_git}${__ps_color_fg_base}"

    # Description: https://github.com/njhartwell/pw3nage
    # Related fix in git-bash: https://github.com/git/git/blob/9d77b0405ce6b471cb5ce3a904368fc25e55643d/contrib/completion/git-prompt.sh#L324
    if shopt -q promptvars; then
      escaped_repository_status="$(__ps_repository_status)"
      PS1+="\${escaped_repository_status}"
    else
      PS1+="$(__ps_repository_status)"
    fi

    PS1+="| \\A ${__ps_color_reset}\\nλ "
  }

  PROMPT_COMMAND="__ps_ps1; ${PROMPT_COMMAND}"
}

__ps_main && unset -f __ps_main