hledger-install.sh

#!/bin/bash
# Easy hledger installation script for POSIX systems, requiring bash and some other POSIX tools.
# This is based on a snapshot of get-stack.sh which was copyright (c) 2015-2017, Stack contributors.

# This was disabled as a workaround for https://github.com/simonmichael/hledger/issues/714
# It has been left off so that one uninstallable tool doesn't block the others.
# (XXX though, try_install is supposed to continue on failure)
#set -e
set -o pipefail

# This install script's name (can't use $0 when it's piped into bash).
HLEDGER_INSTALL_TOOL=hledger-install.sh

# This install script's version.
HLEDGER_INSTALL_VERSION=20240601

# Tools to be installed by this install script, official tools first.
# Keep synced with the package versions below.
# When changing remember to also bump HLEDGER_INSTALL_VERSION.
HLEDGER_TOOLS="\
hledger \
hledger-ui \
hledger-web \
hledger-edit \
hledger-lots \
hledger-plot \
hledger-interest \
hledger-iadd \
pricehist \
"

# Additional install-related tools to be listed
INSTALL_TOOLS="\
stack \
cabal \
pip \
"

# Package versions to be installed by this install script.
# Keep synced with the tools above. 
# When changing remember to also bump HLEDGER_INSTALL_VERSION.
# Official:
HLEDGER_LIB_VERSION=1.34
HLEDGER_VERSION=1.34
HLEDGER_UI_VERSION=1.34
HLEDGER_WEB_VERSION=1.34
# Third-party:
HLEDGER_IADD_VERSION=1.3.21
HLEDGER_INTEREST_VERSION=1.6.6
HLEDGER_EDIT_VERSION=1.14.0
HLEDGER_PLOT_VERSION=1.14.0
HLEDGER_LOTS_VERSION=0.4.2
PRICEHIST_VERSION=1.4.6

# this script's one-line description
HLEDGER_INSTALL_DESC="$HLEDGER_INSTALL_TOOL version $HLEDGER_INSTALL_VERSION to install hledger $HLEDGER_VERSION and related tools"

usage() {
  cat <<HERE
$HLEDGER_INSTALL_DESC

hledger-install.sh [-f|--force-install-stack] [-s|--status] [-v|--verbose]
                   [--version] [-h|--help]

This script builds and installs the current release of hledger and addons,
on a GHC-supporting POSIX system with bash installed, as reliably as possible.
Run it the security-conscious way:

 curl -sSLO https://hledger.org/hledger-install.sh  # download
 less hledger-install.sh                            # review for malware
 bash -x hledger-install.sh                         # run it, showing commands

or the lazy way:

 curl -sSL https://hledger.org/hledger-install.sh | bash

The stack build tool is used by preference, and will be installed if needed.
The cabal build tool will be used instead if it is installed and stack is not,
and the -f/--force-install-stack flag is not used,

Note building can require 2G or more of both memory and disk space,
and could take up to an hour (subsequent runs will be faster).
You can kill and rerun it without losing progress.

To just show which hledger tools are currently installed, run with the -s flag.

HERE
}

# the oldest version of stack that might possibly work: perhaps 2.5.1
STACK_MIN_VERSION=2.5.1

# stackage snapshot to use when installing with stack.
# You can try specifying a different stackage version here, or 
# commenting out this line to use your current global resolver,
# to avoid unnecessary building.
STACK_RESOLVER="--resolver=nightly-2024-05-16"

# Dependencies we require that aren't in the above stackage snapshot.
# (Also requested when using cabal, but that's harmless.)
# Be careful not to break interpolation in commands below, the format should be
# STACK_EXTRA_DEPS="PKG1-VER1 PKG2-VER2 ..."
# extra deps as in stack9.6.yaml:
STACK_EXTRA_DEPS=""

#TODO? https://github.com/commercialhaskell/stack/issues/3055 https://github.com/haskell/hackage-security/issues/187
#Updating package index Hackage (mirrored at https://s3.amazonaws.com/hackage.fpcomplete.com/) ...
#   /Users/simon/.stack/indices/Hackage/hackage-security-lock: createDirectory: already exists (File exists)

##############################################################################
# Below is (most of) FP Complete's/Stack team's get-stack.sh, from
# https://github.com/commercialhaskell/stack/blob/master/etc/scripts/get-stack.sh .
# CHANGED marks a few of our customisations, but not all.
##############################################################################

HOME_LOCAL_BIN="$HOME/.local/bin"
USR_LOCAL_BIN="/usr/local/bin"
QUIET=""
FORCE_INSTALL_STACK=""
STACK_TEMP_DIR=

# creates a temporary directory, which will be cleaned up automatically
# when the script finishes
make_temp_dir() {
  STACK_TEMP_DIR="$(mktemp -d 2>/dev/null || mktemp -d -t stack)"
}

# cleanup the temporary directory if it's been created.  called automatically
# when the script exits.
cleanup_temp_dir() {
  if [ -n "$STACK_TEMP_DIR" ] ; then
    rm -rf "$STACK_TEMP_DIR"
    STACK_TEMP_DIR=
  fi
}

# print a message to stderr and exit with error code
die() {
  echo "$@" >&2
  exit 1
}

# print a message to stdout unless '-q' passed to script
info() {
  if [ -z "$QUIET" ] ; then
    echo "$@"
  fi
}

# print a separator for post-install messages
post_install_separator() {
  info ""
  info "-------------------------------------------------------------------------------"
  info ""
}

# determines the the CPU's instruction set
get_isa() {
  if arch | grep -q arm ; then
    echo arm
  else
    echo x86
  fi
}

# exits with code 0 if arm ISA is detected as described above
is_arm() {
  test "$(get_isa)" = arm
}


# determines 64- or 32-bit architecture
# if getconf is available, it will return the arch of the OS, as desired
# if not, it will use uname to get the arch of the CPU, though the installed
# OS could be 32-bits on a 64-bit CPU
get_arch() {
  if has_getconf ; then
    if getconf LONG_BIT | grep -q 64 ; then
      echo 64
    else
      echo 32
    fi
  else
    case "$(uname -m)" in
      *64)
        echo 64
        ;;
      *)
        echo 32
        ;;
    esac
  fi
}

# exits with code 0 if a 64-bit architecture is detected as described above
is_64_bit() {
  test "$(get_arch)" = 64
}

# prints a generic bindist notice
print_bindist_notice() {
  if [ -z "$1" ] ; then
    info ""
    info "Using generic bindist..."
    info ""
  else
    info ""
    info "Using generic $1 bindist..."
    info ""
  fi
}

# Adds a `sudo` prefix if sudo is available to execute the given command
# If not, the given command is run as is
sudocmd() {
  $(command -v sudo) "$@"
}

# Install dependencies for distros that use Apt
apt_install_dependencies() {
    info "Installing dependencies..."
    info ""
    apt_get_install_pkgs "$@"
}

# Attempts an install on Ubuntu via apt, if possible
# Expects the version (in Major.Minor format, with any sub-minor removed)
# as the first and only argument
# If the version of Ubuntu is unsupported, it attempts to copy the binary
# and install the necessary dependencies explicitly.
do_ubuntu_install() {

  install_dependencies() {
    apt_install_dependencies g++ gcc libc6-dev libffi-dev libgmp-dev make xz-utils zlib1g-dev git gnupg  libtinfo-dev
  }

  if is_arm ; then
    install_dependencies
    print_bindist_notice
    install_arm_binary
  elif is_64_bit ; then
    install_dependencies
    print_bindist_notice
    install_64bit_linux_binary
  else
    install_dependencies
    print_bindist_notice
    install_32bit_standard_binary
  fi

}

# Attempts an install on Debian.
# Expects the single-number version as the first and only argument
# If the version of Debian is unsupported, it attempts to copy the binary
# and install the necessary dependencies explicitly.
do_debian_install() {

  install_dependencies() {
    apt_install_dependencies g++ gcc libc6-dev libffi-dev libgmp-dev make xz-utils zlib1g-dev libtinfo-dev
  }

  if is_arm ; then
    install_dependencies
    print_bindist_notice
    install_arm_binary
  elif is_64_bit ; then
    install_dependencies
    print_bindist_notice
    install_64bit_linux_binary
  else
    install_dependencies
    print_bindist_notice
    install_32bit_standard_binary
  fi
}

# Attempts an install on Fedora.
# Expects the single-number version as the first and only argument
# If the version of Fedora is unsupported, it attempts to copy the binary
# and install the necessary dependencies explicitly.
do_fedora_install() {
  install_dependencies() {
    dnf_install_pkgs perl make automake gcc gmp-devel libffi zlib xz tar
  }

  if is_64_bit ; then
    install_dependencies "$1"
    print_bindist_notice
    install_64bit_linux_binary
  else
    install_dependencies "$1"
    print_bindist_notice
    install_32bit_standard_binary
  fi
}

# Attempts an install on CentOS.
# Expects the single-number version as the first and only argument
# If the version of CentOS is unsupported, it attempts to copy the binary
# and install the necessary dependencies explicitly.
do_centos_install() {
  install_dependencies() {
    yum_install_pkgs perl make automake gcc gmp-devel libffi zlib xz tar
  }

  if is_64_bit ; then
    install_dependencies
    print_bindist_notice
    install_64bit_linux_binary
  else
    install_dependencies
    case "$1" in
      "6")
        print_bindist_notice "libgmp4"
        install_32bit_gmp4_linked_binary
        ;;
      *)
        print_bindist_notice
        install_32bit_standard_binary
        ;;
    esac
  fi
}

# Attempts to install on macOS.
# If 'brew' exists, installs using Homebrew.  Otherwise, installs
# the generic bindist.
do_osx_install() {
  info "Using generic bindist..."
  info ""
  install_64bit_osx_binary
#CHANGED
#  info "NOTE: You may need to run 'xcode-select --install' to set"
#  info "      up the Xcode command-line tools, which Stack uses."
#  info ""
  echo "NOTE: You may need to run 'xcode-select --install' to set"
  echo "      up the Xcode command-line tools, which Stack uses."
  echo ""
}

# Attempts to install on FreeBSD.  Installs dependencies with
# 'pkg install' and then downloads bindist.
do_freebsd_install() {
  install_dependencies() {
    pkg_install_pkgs devel/gmake perl5 lang/gcc misc/compat8x misc/compat9x converters/libiconv ca_root_nss
  }
  if is_64_bit ; then
    install_dependencies
    install_64bit_freebsd_binary
  else
    die "Sorry, there is currently no 32-bit FreeBSD binary available."
  fi
}

# Alpine distro install
do_alpine_install() {
  install_dependencies() {
    apk_install_pkgs gmp libgcc xz make
  }
  install_dependencies
  if is_64_bit ; then
    install_64bit_linux_binary
  else
    die "Sorry, there is currently no 32-bit Alpine Linux binary available."
  fi
}

# Attempts to install on unsupported Linux distribution by downloading
# the bindist.
do_sloppy_install() {
  info "This installer doesn't support your Linux distribution, trying generic"
  info "bindist..."
  info ""

  if is_arm ; then
      install_arm_binary
  elif is_64_bit ; then
      install_64bit_linux_binary
  else
      install_32bit_standard_binary
  fi
  info "Since this installer doesn't support your Linux distribution,"
  info "there is no guarantee that 'stack' will work at all!  You may"
  info "need to manually install some system info dependencies for GHC:"
  info "  gcc, make, libffi, zlib, libgmp and libtinfo"
  info "Please see http://docs.haskellstack.org/en/stable/install_and_upgrade/"
  info "Pull requests to add support for this distro would be welcome!"
  info ""
}

# Attempts to determine the running Linux distribution.
# Prints "DISTRO;VERSION" (distribution name and version)"."
distro_info() {
  parse_lsb() {
    lsb_release -a 2> /dev/null | perl -ne "$1"
  }

  try_lsb() {
    if has_lsb_release ; then
      TL_DIST="$(parse_lsb 'if(/Distributor ID:\s+([^ ]+)/) { print "\L$1"; }')"
      TL_VERSION="$(parse_lsb 'if(/Release:\s+([^ ]+)/) { print "\L$1"; }')"
      echo "$TL_DIST;$TL_VERSION"
    else
      return 1
    fi
  }

  try_release() {
    parse_release() {
      perl -ne "$1" /etc/*release 2>/dev/null
    }

    parse_release_id() {
      parse_release 'if(/^(DISTRIB_)?ID\s*=\s*"?([^"]+)/) { print "\L$2"; exit 0; }'
    }

    parse_release_version() {
      parse_release 'if(/^(DISTRIB_RELEASE|VERSION_ID)\s*=\s*"?([^"]+)/) { print $2; exit 0; }'
    }

    TR_RELEASE="$(parse_release_id);$(parse_release_version)"

    if [ ";" = "$TR_RELEASE" ] ; then
      if [ -e /etc/arch-release ] ; then
        # /etc/arch-release exists but is often empty
        echo "arch;"
      elif [ -e /etc/centos-release ] && grep -q "\\<6\\>" /etc/centos-release ; then
        # /etc/centos-release has a non-standard format before version 7
        echo "centos;6"
      else
        return 1
      fi
    else
      echo "$TR_RELEASE"
    fi
  }

  try_issue() {
    case "$(cat /etc/issue 2>/dev/null)" in
      "Arch Linux"*)
        echo "arch;" # n.b. Version is not available in /etc/issue on Arch
        ;;
      "Ubuntu"*)
        echo "ubuntu;$(perl -ne 'if(/Ubuntu (\d+\.\d+)/) { print $1; }' < /etc/issue)"
        ;;
      "Debian"*)
        echo "debian;$(perl -ne 'if(/Debian GNU\/Linux (\d+(\.\d+)?)/) { print $1; }' < /etc/issue)"
        ;;
      *"SUSE"*)
        echo "suse;$(perl -ne 'if(/SUSE\b.* (\d+\.\d+)/) { print $1; }' < /etc/issue)"
        ;;
      *"NixOS"*)
        echo "nixos;$(perl -ne 'if(/NixOS (\d+\.\d+)/) { print $1; }' < /etc/issue)"
        ;;
      "CentOS"*)
        echo "centos;$(perl -ne 'if(/^CentOS release (\d+)\./) { print $1; }' < /etc/issue)"
        ;;
      *)
    esac
    # others do not output useful info in issue, return empty
  }

  try_lsb || try_release || try_issue
}

# Attempt to install on a Linux distribution
do_distro() {
  if ! has_perl ; then
    if ! try_install_pkgs perl ; then
      #TODO: remove dependence on 'perl', which is not installed by default
      #on some distributions (Fedora and RHEL, in particular).
      die "This script requires 'perl', please install it to continue."
    fi
  fi

  IFS=";" read -r DISTRO VERSION <<GETDISTRO
$(distro_info)
GETDISTRO

  if [ -n "$DISTRO" ] ; then
    info "Detected Linux distribution: $DISTRO"
    info ""
  fi

  case "$DISTRO" in
    ubuntu)
      do_ubuntu_install "$VERSION"
      ;;
    debian|kali|raspbian)
      do_debian_install "$VERSION"
      ;;
    fedora)
      do_fedora_install "$VERSION"
      ;;
    centos|rhel)
      do_centos_install "$VERSION"
      ;;
    alpine)
      do_alpine_install "$VERSION"
      ;;
    *)
      do_sloppy_install
  esac
}

# Determine operating system and attempt to install.
do_os() {
  case "$(uname)" in
    "Linux")
      do_distro
      ;;
    "Darwin")
      do_osx_install
      ;;
    "FreeBSD")
      do_freebsd_install
      ;;
    *)
      die "Sorry, this installer does not support your operating system: $(uname).
See http://docs.haskellstack.org/en/stable/install_and_upgrade/"
  esac
}

# Download a URL to file using 'curl' or 'wget'.
dl_to_file() {
  if has_curl ; then
    if ! curl ${QUIET:+-sS} -L -o "$2" "$1"; then
      die "curl download failed: $1"
    fi
  elif has_wget ; then
    if ! wget ${QUIET:+-q} "-O$2" "$1"; then
      die "wget download failed: $1"
    fi
  else
    # should already have checked for this, otherwise this message will probably
    # not be displayed, since dl_to_stdout will be part of a pipeline
    die "Neither wget nor curl is available, please install one to continue."
  fi
}

# Check for 'curl' or 'wget' and attempt to install 'curl' if neither found,
# or fail the script if that is not possible.
check_dl_tools() {
  if ! has_curl && ! has_wget ; then
    if ! try_install_pkgs curl ; then
      die "Neither wget nor curl is available, please install one to continue."
    fi
  fi
}

# Download a Stack bindst and install it in /usr/local/bin/stack.
install_from_bindist() {
    IFB_URL="https://www.stackage.org/stack/$1"
    check_dl_tools
    make_temp_dir

    dl_to_file "$IFB_URL" "$STACK_TEMP_DIR/$1.bindist"
    mkdir -p "$STACK_TEMP_DIR/$1"
    if ! tar xzf "$STACK_TEMP_DIR/$1.bindist" -C "$STACK_TEMP_DIR/$1"; then
      die "Extract bindist failed"
    fi
#CHANGED
#    if ! sudocmd install -c -o 0 -g 0 -m 0755 "$STACK_TEMP_DIR/$1"/*/stack "$USR_LOCAL_BIN/stack"; then
#      die "Install to $USR_LOCAL_BIN/stack failed"
    ensure_home_local_bin
    if ! install -m 0755 "$STACK_TEMP_DIR/$1"/*/stack "$HOME_LOCAL_BIN/stack"; then
      die "Install to $HOME_LOCAL_BIN/stack failed"
    fi

    post_install_separator
#CHANGED
#    info "Stack has been installed to: $USR_LOCAL_BIN/stack"
    echo "Stack has been installed to: $HOME_LOCAL_BIN/stack"
    info ""

#CHANGED
#    check_usr_local_bin_on_path
}

install_arm_binary() {
  install_from_bindist "linux-arm"
}

install_32bit_standard_binary() {
  install_from_bindist "linux-i386"
}

install_64bit_linux_binary() {
  install_from_bindist "linux-x86_64"
}

install_64bit_static_binary() {
  install_from_bindist "linux-x86_64-static"
}

install_32bit_gmp4_linked_binary() {
  install_from_bindist "linux-i386-gmp4"
}

install_64bit_osx_binary() {
  install_from_bindist "osx-x86_64"
}

install_64bit_freebsd_binary() {
  install_from_bindist "freebsd-x86_64"
}

# Attempt to install packages using whichever of apt-get, dnf, yum, or apk is
# available.
try_install_pkgs() {
  if has_apt_get ; then
    apt_get_install_pkgs "$@"
  elif has_dnf ; then
    dnf_install_pkgs "$@"
  elif has_yum ; then
    yum_install_pkgs "$@"
  elif has_apk ; then
    apk_install_pkgs "$@"
  else
    return 1
  fi
}

# Install packages using apt-get
apt_get_install_pkgs() {
  if ! sudocmd apt-get install -y ${QUIET:+-qq} "$@"; then
    die "Installing apt packages failed.  Please run 'apt-get update' and try again."
  fi
}

# Install packages using dnf
dnf_install_pkgs() {
  if ! sudocmd dnf install -y ${QUIET:+-q} "$@"; then
    die "Installing dnf packages failed.  Please run 'dnf check-update' and try again."
  fi
}

# Install packages using yum
yum_install_pkgs() {
  if ! sudocmd yum install -y ${QUIET:+-q} "$@"; then
    die "Installing yum packages failed.  Please run 'yum check-update' and try again."
  fi
}

# Install packages using apk
apk_install_pkgs() {
  if ! sudocmd apk add --update ${QUIET:+-q} "$@"; then
    die "Installing apk packages failed.  Please run 'apk update' and try again."
  fi
}

# Install packages using pkg
pkg_install_pkgs() {
    if ! sudocmd pkg install -y "$@"; then
        die "Installing pkg packages failed.  Please run 'pkg update' and try again."
    fi
}

# Get installed Stack version, if any.
stack_version_number() {
  stack --version | grep -o 'Version \([[:digit:]]\|\.\)\+'
}

# Get Stack's --version output, trimmed for sanity, if it is installed.
stack_version_quiet() {
  stack --version | grep -E -v '^(Compiled|- |$)'
}

# Get installed Stack's path
stack_location() {
  command -v stack
}

# Check whether 'stack' command exists
has_stack() {
  has_cmd stack
}

# Check whether a new enough version of the 'stack' command exists
has_good_stack() {
  has_cmd stack &&
  [[ ! $(cmpver "$(cmd_version stack 2>/dev/null)" $STACK_MIN_VERSION) = 2 ]]
}

# Check whether 'wget' command exists
has_wget() {
  has_cmd wget
}

# Check whether 'curl' command exists
has_curl() {
  has_cmd curl
}

# Check whether 'lsb_release' command exists
has_lsb_release() {
  has_cmd lsb_release
}

# Check whether 'sudo' command exists
has_sudo() {
  has_cmd sudo
}

# Check whether 'getconf' command exists
has_getconf() {
  has_cmd getconf
}

# Check whether 'brew' command exists
#has_brew() {
#  has_cmd brew
#}

# Check whether 'perl' command exists
has_perl() {
  has_cmd perl
}

# Check whether 'apt-get' command exists
has_apt_get() {
  has_cmd apt-get
}

# Check whether 'yum' command exists
has_yum() {
  has_cmd yum
}

# Check whether 'apk' command exists
has_apk() {
  has_cmd apk
}

# Check whether 'dnf' command exists
has_dnf() {
  has_cmd dnf
}

# Check whether the given command exists
has_cmd() {
  command -v "$1" > /dev/null 2>&1
}

# Ensure that $HOME/.local/bin/ exists, or die.
ensure_home_local_bin() {
  install -d "$HOME_LOCAL_BIN" || die "Creating $HOME_LOCAL_BIN/ directory failed"
}

# Check whether the given path is listed in the PATH environment variable
on_path() {
  echo ":$PATH:" | grep -q :"$1":
}

# Check whether ~/.local/bin is on the PATH, and print a warning if not.
check_home_local_bin_on_path() {
  if ! on_path "$HOME_LOCAL_BIN" ; then
    #TODO: offer to add it for the user (pull requests welcome!)
    info "WARNING: '$HOME_LOCAL_BIN' is not on your PATH."
    info "    For best results, please add it to the beginning of PATH in your profile."
    info ""
  fi
}

# Check whether /usr/local/bin is on the PATH, and print a warning if not.
check_usr_local_bin_on_path() {
  if ! on_path "$USR_LOCAL_BIN" ; then
    info "WARNING: '$USR_LOCAL_BIN' is not on your PATH."
    info ""
  fi
}

# Check whether Stack is already installed, and print an error if it is.
check_stack_installed() {
  if [ "$FORCE_INSTALL_STACK" != "true" ] && has_good_stack ; then
    die "Stack $(stack_version_number) already appears to be installed at:
  $(stack_location)
Use 'stack upgrade' or your OS's package manager to upgrade,
or pass --force-install-stack to this script to install anyway."
  fi
}

trap cleanup_temp_dir EXIT

# end of (most of) get-stack.sh

# hledger routines

# Compare dotted number version strings, based on https://stackoverflow.com/a/4025065/84401.
# cmpver A B's exit status *and* output is
# 0 for A ~= B (1 is equivalent to 1.0, 1.0.0 etc.)
# 1 for A > B
# 2 for A < B.
cmpver () {
    if [[ $1 == $2 ]]
    then
        echo 0; return 0
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            echo 1; return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            echo 2; return 2
        fi
    done
    echo 0; return 0
}

# install stack or a newer version of stack if needed, 
# or always with --force-install-stack, 
# in $HOME/.local/bin.
# After installing, check that a new-enough stack is now the first in $PATH,
# and if it's not, exit with a warning advising the user to remove the old one. 
ensure_stack() {
  if ! has_good_stack || [[ "$FORCE_INSTALL_STACK" == "true" ]] ; then
    echo "Installing stack"
    do_os
    if ! has_good_stack ; then
      echo "Error: an older stack ($(cmd_version stack)) is first in \$PATH, shadowing the new version."
      echo "Please delete or rename $(which stack) and run hledger-install again."
      exit 1
    fi
  fi
  echo "Using stack $(stack_version_quiet)"
}

# get a sed command that supports EREs
if sed -r </dev/null >/dev/null 2>&1 ; then
  SED="sed -r"
else
  SED="sed -E"
fi

# Get the given command's location, or empty string if it's not in $PATH.
cmd_location() {
  command -v "$1"
}

# Get the given command's version, ie the first number in the first line of its --version output,
# or empty string if there's a problem.
cmd_version() {
  (command "$1" --version 2>/dev/null | head -n1 | grep -E '[0-9]' | $SED -e 's/[^0-9]*([0-9][0-9.]*).*/\1/') || ""
}

# Check whether the given command exists with given version
has_cmd_version() {
  [[ $(cmd_version "$1") == "$2" ]]
}

# Show a command's presence in $PATH, and its version if present.
print_cmd_version() {
  if [[ $(cmd_location "$1") ]]; then
    printf "%-28s is installed at %s\n" "$1 $(cmd_version "$1")" $(cmd_location "$1")
  else
    echo "$1 is not found"
  fi
}

# Show the current installation status of the hledger packages.
print_installed_versions() {
  for cmd in $INSTALL_TOOLS $HLEDGER_TOOLS ; do print_cmd_version "$cmd"; done
}

# Run a command, but first log it with "Trying" prepended.
try_info() {
  echo Trying "$@"
  "$@"
}

# Run a command if possible, suppressing any error output or non-zero exit code.
quietly_run() {
  "$@" 2>/dev/null || true
}

# Try to install the executables of the given haskell package versions,
# using stack or cabal, logging the commands, continuing on failure.
# It's assumed that either a new-enough stack or cabal-install is already installed.
# stack is preferred.
# For stack, you must specify the package(s) you want to install, plus any additional
# dependency packages which are not in the stackage $STACK_RESOLVER configured above.
try_install() {
  cd  # ensure we install at user level, not in some project's stack/cabal setup
  if has_cmd stack ; then
    try_info stack install --install-ghc $STACK_RESOLVER "$@" --verbosity="$STACK_VERBOSITY" || echo "Failed to install $@"
  elif has_cmd cabal ; then
    try_info cabal install "$@" --verbose="$CABAL_VERBOSITY" || echo "Failed to install $@"
  else
    echo "Failed to install $@"
  fi
}

# Try to install the given python package versions,
# using pip, logging the commands, continuing on failure.
try_install_py() {
  cd  # ensure we install at user level, not in some project's env
  if has_cmd pip ; then
    try_info pip install --disable-pip-version-check -U "$@" $PIP_VERBOSITY
  else
    echo "Failed to install $@"
  fi
}

# start

# process command-line flags

HELPFLAG=""
STATUSFLAG=""
VERBOSEFLAG=""
VERSIONFLAG=""

while [ $# -gt 0 ]; do
  case "$1" in
    -f|--force-install-stack)
      FORCE_INSTALL_STACK="true"
      shift
      ;;
    -v|--verbose)
      VERBOSEFLAG="true"
      shift
      ;;
    -s|--status)
      STATUSFLAG="true"
      shift
      ;;
    --version)
      VERSIONFLAG="true"
      shift
      ;;
    -h|--help)
      HELPFLAG="true"
      shift
      ;;
    *)
      echo "Invalid argument: $1" >&2
      exit 1
      ;;
  esac
done

if [[ $HELPFLAG ]] ; then
  usage
  exit 0
fi

if [[ $VERSIONFLAG ]] ; then
  echo "$HLEDGER_INSTALL_TOOL version $HLEDGER_INSTALL_VERSION, installs hledger $HLEDGER_VERSION and related tools"
  exit 0
fi

if [[ $VERBOSEFLAG ]]; then
  CABAL_VERBOSITY=1       # 0-3
  STACK_VERBOSITY=info    # silent, error, warn, info, debug
  PIP_VERBOSITY=-v
else
  CABAL_VERBOSITY=0
  # info shows too many warnings, but error hides install plan failure details,
  # and still shows warnings.
  # STACK_VERBOSITY=info
  # Try error again. It looks much better, and it might have improved by now.
  # If there's trouble, they must rerun with --verbose.
  STACK_VERBOSITY=error
  PIP_VERBOSITY=-q
  QUIET=true
fi

date
echo "Running $HLEDGER_INSTALL_DESC"

# ensure ~/.local/bin/ in PATH
# TODO should check ~/.cabal/bin if using cabal
if ! on_path "$HOME_LOCAL_BIN" ; then
  echo "WARNING: this script installs hledger (and perhaps stack) in '$HOME_LOCAL_BIN'"
  echo "  but this directory is not in your PATH. Adding it temporarily. To run"
  echo "  these things easily, please add it to PATH in your shell profile."
  echo "  Eg, bash users: "
  echo "    echo \"export PATH=\$PATH:~/.local/bin\" >> ~/.bashrc && source ~/.bashrc"
  export PATH=$HOME_LOCAL_BIN:$PATH
fi

# show system info
printf "on "
quietly_run uname -rsv
quietly_run lsb_release -a

# show current installed hledger packages
echo
echo "Current install status:"
print_installed_versions

if [[ $STATUSFLAG ]] ; then
  exit 0
fi

# ensure a haskell build tool
echo
echo "Ensuring a Haskell build tool:"
# if stack is installed, use stack
# || [[ "$FORCE_INSTALL_STACK" == "true" ]]  #--force-install-stack
if has_stack ; then
  echo "stack $(cmd_version stack) is installed, using stack to install hledger in $HOME/.local/bin"
  # if it's too old, explain that we'll be installing the latest
  if ! has_good_stack ; then
    echo "Note: stack $(cmd_version stack) is too old, a newer version will be installed"
  fi
  # install stack now (or if new enough, just print its precise version)
  ensure_stack
  echo "Updating stack's package db to see latest packages"
  try_info stack update --verbosity=error
# else if cabal is installed, use cabal
elif has_cmd cabal ; then
  echo "no stack installed, cabal $(cabal --numeric-version) installed; using cabal to install hledger in $HOME/.cabal/bin"
  echo Using $(cabal --version)  # unquoted to squash cabal version to one line
  # run cabal update to make sure it knows about latest packages
  try_info cabal update -v0
# else use stack
else
  echo "no stack or cabal installed; stack will be installed and used to install hledger in $HOME/.local/bin"
    # install stack now
  ensure_stack
fi

# ensure a python install tool
echo
echo "Ensuring the Python pip install tool:"
if has_cmd pip ; then
  echo "$(pip --version) is installed"
else
  echo "pip was not found; python-based addons will not be installed"
fi

# try installing each package that needs installing, in turn
echo
echo "Installing hledger tools:"

if [[ $(cmpver "$(cmd_version hledger 2>/dev/null)" $HLEDGER_VERSION) = 2 ]]; then
  echo Installing hledger
  try_install hledger-$HLEDGER_VERSION hledger-lib-$HLEDGER_LIB_VERSION $STACK_EXTRA_DEPS
  echo
fi

if [[ $(cmpver "$(cmd_version hledger-ui 2>/dev/null)" $HLEDGER_UI_VERSION) = 2 ]]; then
  echo Installing hledger-ui
  try_install hledger-ui-$HLEDGER_UI_VERSION hledger-$HLEDGER_VERSION hledger-lib-$HLEDGER_LIB_VERSION $STACK_EXTRA_DEPS \
    # brick-X.Y   # when hledger-iadd requires a special brick, use the same here to reduce rebuilding
  echo
fi

if [[ $(cmpver "$(cmd_version hledger-web 2>/dev/null)" $HLEDGER_WEB_VERSION) = 2 ]]; then
  echo Installing hledger-web
  try_install hledger-web-$HLEDGER_WEB_VERSION hledger-$HLEDGER_VERSION hledger-lib-$HLEDGER_LIB_VERSION $STACK_EXTRA_DEPS
  echo
fi

# Third-party addons.
# We might have to build these with an older version of hledger,
# if they have not been updated yet.

if [[ $(cmpver "$(cmd_version hledger-iadd 2>/dev/null)" $HLEDGER_IADD_VERSION) = 2 ]]; then
  echo Installing hledger-iadd
  try_install hledger-iadd-$HLEDGER_IADD_VERSION hledger-lib-$HLEDGER_LIB_VERSION $STACK_EXTRA_DEPS
  echo
else
  echo hledger-iadd is up to date
fi

if [[ $(cmpver "$(cmd_version hledger-interest 2>/dev/null)" $HLEDGER_INTEREST_VERSION) = 2 ]]; then
  echo Installing hledger-interest
  try_install hledger-interest-$HLEDGER_INTEREST_VERSION hledger-lib-$HLEDGER_LIB_VERSION $STACK_EXTRA_DEPS
  echo
else
  echo hledger-interest is up to date
fi

if [[ $(cmpver "$(cmd_version pricehist 2>/dev/null)" $PRICEHIST_VERSION) = 2 ]]; then
  echo Installing pricehist
  try_install_py pricehist
  echo
else
  echo pricehist is up to date
fi

# hledger-edit, hledger-plot packaged together as hledger-utils, just install it twice for now
if [[ $(cmpver "$(cmd_version hledger-edit 2>/dev/null)" $HLEDGER_EDIT_VERSION) = 2 ]]; then
  echo Installing hledger-edit
  try_install_py hledger-utils
  echo
else
  echo hledger-edit is up to date
fi

if [[ $(cmpver "$(cmd_version hledger-plot 2>/dev/null)" $HLEDGER_PLOT_VERSION) = 2 ]]; then
  echo Installing hledger-plot
  try_install_py hledger-utils
  echo
else
  echo hledger-plot is up to date
fi

if [[ $(cmpver "$(cmd_version hledger-lots 2>/dev/null)" $HLEDGER_LOTS_VERSION) = 2 ]]; then
  echo Installing hledger-lots
  try_install_py hledger-lots
  echo
else
  echo hledger-lots is up to date
fi

# show new installation status
echo
echo "New install status:"
print_installed_versions

# warn if $HOME/.local/bin isn't in $PATH
check_home_local_bin_on_path
# TODO if we installed with cabal, we should check $HOME/.cabal/bin instead

# TODO
# check/require ghc-8.0.2+/lts-8+ on osx sierra+
# automate testing
# install hledger experimental tools
# help install c libs
# try installing system packages
# help with logging & reporting successes/failures
# detect latest hledger version & resolver ?
# detect latest installer version, self upgrade ?