#!/bin/bash

function usage {
  cat <<- EOF
  ./scrape.sh [options]

  Scrape facebook event pages.

  OPTIONS:
    -h --help -?                      print usage
    --events                          File in JSON format that contains an array
                                      of prevously parsed events. This option
                                      will disable image scraping of previously
                                      scraped events.
    -p --page                         Facebook page id. Scrape all events of a
                                      specific facebook page.
    --pages                           List of Facebook page ids. See examples for
                                      format.
    -o --output                       Output events into this path instead of
                                      stdout.
    -i --images (experimental)        Scrape event images.
    --image-directory                 Default: './img'. Set directory for saving
                                      event images.
    --skip-upcoming-events            Default: The scraper will automatically
                                      scrape upcoming events, with this option
                                      enabled they will be skipped.
    --past-events (experimental)      Default: The scraper will not scrape past
                                      events by default. Enabling this option
                                      makes the scraper include past events.
                                      Please note that this might take a while
                                      depending on the number of past events.
    --no-headless                     The scraper will not run in headless mode.

  NOTE:
  Events and pages needs to be public. Private events or pages are not yet
  supported.

  EXAMPLES:
  # Select files with options
  ./scrape.sh -p livesentralen -o events.json --events=events.json

  # You can redirect standard output into a file
  ./scrape.sh --pages="livesentralen,tyventrondheim" > events.json

EOF
}

function parse_args {
  if [ "$1" = "" ]; then
    usage
    exit 0
  fi
}

function install_node_dependencies {
  if ! [ -d node_modules ]; then
    yarn
  fi
}

function check_dependencies {
  local missing;
  missing=false;

  if [ ! $(command -v node) ]; then
    echo "Dependency missing. Please install node.js and make it available to the path as 'node'."
    missing=true
  fi

  if [ ! $(command -v yarn) ]; then
    echo "Dependency missing. Please install yarn and make it available to the path as 'yarn'."
    missing=true
  fi

  install_node_dependencies

  if [ "${missing}" != "false" ]; then
    exit 1;
  fi

  return 0;
}

function scrape {
  node src/scrape.js "$@" || usage
}

check_dependencies \
  && parse_args "$@" \
  && scrape "$@"