#!/bin/bash
# Copyright 2015 The Vanadium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# Check for bash
[[ -z "$BASH_VERSION" ]] && return

# Extracts subcommands from the help output of a given command ($1).
# An example help output from "jiri help":
# ...
# The jiri commands are:
#    build        Tool for managing vanadium builds
#    contributors List vanadium project contributors
#    ...
# Run "jiri help [command]" for command usage.
# ...
_jiri_extract_subcommands() {
  local -r CMD="$1"
  local -r START_LINE="The .* commands are"
  local -r END_LINE="Run \"jiri"
  ${CMD} -h > /dev/null 2>&1
  if [[ "$?" = 0 ]]; then
    ${CMD} -h \
      | sed -n "/${START_LINE}/,/${END_LINE}/p" | grep '^   '| awk '{print $1}' | sort
  fi
}

# Extracts flags from the help output of a given command ($1).
# Note that we ignore all "global" flags.
# An example help output from "jiri help update":
# ...
# The jiri update flags are:
#  -gc=false
#    Garbage collect obsolete repositories.
#  -n=false
# ...
_jiri_extract_flags() {
  local -r CMD="$1"
  local -r START_LINE="The .* flags are"
  local -r END_LINE="^$"
  ${CMD} -h > /dev/null 2>&1
  if [[ "$?" = 0 ]]; then
    ${CMD} -h | sed -n "/${START_LINE}/,/${END_LINE}/p" | grep '^ -'| cut -d= -f1 | tr -d " " | sort
  fi
}

# Gets the command line before the word where the current cursor is.
_jiri_get_cmdline_before_cursor() {
  local i
  local CMD=""
  for(( i=0; i<COMP_CWORD; i++ )); do
    CMD="${CMD} ${COMP_WORDS[i]}"
  done
  echo "${CMD}"
}

# Gets the names of available projects.
_jiri_get_project_names() {
  jiri project list | sed "s/^.*project=\"\(.*\)\" path.*/\1/"
}


# Main bash completion function for the "jiri" command.
#
# Completion-related internal Bash vars:
# - COMP_WORDS: An array variable consisting of the individual words in the
#   current command line
# - COMP_CWORD: An index into ${COMP_WORDS} of the word containing the current cursor
#   position.
# - COMPREPLY An array variable from which bash reads the possible completions
#   generated by a completion function.
_jiri_complete() {
  local -r CUR="${COMP_WORDS[COMP_CWORD]}"
  local -r CMD="$(_jiri_get_cmdline_before_cursor)"

  case "${CUR}" in
    -*)
      # Complete flags.
      COMPREPLY=($(compgen -W "$(_jiri_extract_flags "${CMD}")" -- ${CUR}))
      ;;
    *)
      # Complete commands.
      if [[ "${COMP_LINE}" =~ .*test(\ )+project.* ]]; then
        # Special handling for completing "jiri test project".
        COMPREPLY=($(compgen -W "$(_jiri_get_project_names)" -- ${CUR}))
      elif [[ "${COMP_LINE}" =~ .*test(\ )+run.* ]]; then
        # Special handling for completing "jiri test run".
        COMPREPLY=($(compgen -W "$(jiri test list)" -- ${CUR}))
      else
        COMPREPLY=($(compgen -W "$(_jiri_extract_subcommands "${CMD}")" -- ${CUR}))
      fi
      ;;
  esac

  return 0
}

# Main bash completion function for the "vcd" command.
_jiri_vcd_complete() {
  local -r CUR="${COMP_WORDS[COMP_CWORD]}"

  COMPREPLY=($(compgen -W "$(_jiri_get_project_names)" -- ${CUR}))
}

complete -F _jiri_complete jiri
complete -F _jiri_vcd_complete vcd