#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

PDF_FILENAME=slides.pdf
RST_FILENAME="${RST_FILENAME:-slides.rst}"
THUMBNAIL_FILENAME=thumbnail.jpg

function clean {
  rm -fr dist/*
  touch dist/.keep

  find . \
    -type f \( -name "${PDF_FILENAME}*" -o -name *.build_temp -o -name ${THUMBNAIL_FILENAME} \) \
    -delete
}

function generate {
  generate:pdf "${@}"
}

function generate:pdf {
  if [ "${1}" == "" ]; then
    echo "Usage: ./${0##*/} ${FUNCNAME[0]} <talk-name>"
    exit 1
  fi

  DIRECTORY_NAME=$1
  shift 1
  pushd "src/${DIRECTORY_NAME}"

  rst2pdf "${RST_FILENAME}" \
    --break-level 1 \
    -e preprocess \
    --fit-background-mode scale \
    --font-path ../fonts \
    --output "../../dist/${DIRECTORY_NAME}.pdf" \
    --stylesheets ../styles/opdavies-light,tango \
    "${@}"

  popd

  tree dist
}

# Generate JPG thumbnails of each slide in a presentation.
function generate:thumbnail {
  if [ "${1}" == "" ]; then
    echo "Usage: ./${0##*/} ${FUNCNAME[0]} <talk-name>"
    exit 1
  fi

  if [ ! -d "src/${1}" ]; then
    echo "${1} not found"
    exit 2
  fi

  generate:pdf "${1}"

  mkdir -p "dist/${1}"

  gs \
    -dBATCH \
    -dDownScaleFactor=3 \
    -dNOPAUSE \
    -r600 \
    -sDEVICE=jpeg \
    -sOutputFile="dist/${1}/%d.jpg" \
    "dist/${1}.pdf"
}

function help {
  printf "%s <task> [args]\n\nTasks:\n" "${0}"

  compgen -A function | grep -v "^_" | cat -n

  printf "\nExtended help:\n  Each task has comments for general usage\n"
}

# Create a new talk.
function new {
  if [ "${1}" == "" ]; then
    echo "Usage: ./${0##*/} ${FUNCNAME[0]} <talk-name>"
    exit 1
  fi

  if [[ -e "src/${1}" ]]; then
    echo "Error: ${1} already exists."
    exit 1
  fi

  mkdir -vp "src/${1}"

  touch "src/${1}/slides.rst"
}

function present {
  TALK_PATH=$1
  shift 1

  pdfpc "${@}" "dist/${TALK_PATH}.pdf"
}

TIMEFORMAT=$'\nTask completed in %3lR'
time "${@:-help}"