#!/bin/bash

# Converts the agent docs here to the ReadTheDocs repo at
# https://github.com/signalfx/product-docs. You will probably have to provide
# the envvar $PRODUCT_DOCS_REPO, which is the directory path to the root of the
# product-docs repo.  It will overwrite any existing agent docs in the repo,
# but will not commit them to git.

# For Mac, Pandoc 2.5 should be used and can be gotten from
# https://github.com/jgm/pandoc/releases/tag/2.5

set -euo pipefail

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
AGENT_REPO_BASE="$SCRIPT_DIR/../.."
PRODUCT_DOCS_REPO="${PRODUCT_DOCS_REPO:-$AGENT_REPO_BASE/../product-docs}"
AGENT_PRODUCT_DOCS="$PRODUCT_DOCS_REPO/integrations/agent"
MANAGE_GIT="${MANAGE_GIT-yes}"

check_pandoc_version() {
	pandoc --version | grep 'pandoc 2.[57]'
}

header_comment() {
  printf ".. Generated by scripts/docs/to-product-docs in signalfx-agent repo. DO NOT EDIT in product-docs!!\n\n"
}

. $SCRIPT_DIR/common.sh

convert_overview_links() {
  sed -E -e 's@../README.html@./overview.html@'
}

# Convert all relative links that aren't already html links to be absolute to
# the github repo url.
convert_relative_links() {
  sed -E -e '/\.html(#.*)?$/! s@(\.\. _[a-zA-Z].*:) \.\/(.*)@\1 https://github.com/signalfx/signalfx-agent/tree/master/\2@'
}

# Changes .md extensions to .html
convert_doc_extensions() {
  sed -E -e '/http:|https:|(development|signalfx-agent.1|MANUAL).md/! s/\.md(#.*)?[[:>:]]/.html\1/g' -e'/(development|signalfx-agent.1).md/! s@\./docs/@./@g'
}

strip_needless_header_refs() {
  sed -E -e '/\.\. _.*default-metrics-version/d'
}

reset_repo() {
  if ! git -C $PRODUCT_DOCS_REPO diff --exit-code; then
    echo "Product docs repo has uncommitted changes, please deal with them first" >&2
    exit 1
  fi

  git -C $PRODUCT_DOCS_REPO fetch origin
  git -C $PRODUCT_DOCS_REPO checkout smart-agent
  # If there aren't any pending commits in the smart-agent branch, then reset
  # with the latest master first
  if [[ -z "$(git cherry -v origin/master origin/smart-agent || echo '')" ]]; then
    git -C $PRODUCT_DOCS_REPO reset --hard origin/master
  fi
}

check_pandoc_version

[ -d $PRODUCT_DOCS_REPO ] || \
  (echo "product-docs repo dir cannot be found at $PRODUCT_DOCS_REPO; please set \$PRODUCT_DOCS_REPO" && exit 1)

if [[ "$MANAGE_GIT" == "yes" ]]; then
  reset_repo
fi

mkdir -p $AGENT_PRODUCT_DOCS/{monitors,observers}

for f in $(find $AGENT_REPO_BASE/docs -name "*.md"); do
  if [[ $f =~ writing-a-monitor.md$ ]] || [[ $f =~ development.md$ ]]; then
    continue
  fi

  out_file=$AGENT_PRODUCT_DOCS/$(echo $f | sed -e "s@${AGENT_REPO_BASE}/docs/@@" | sed 's/md/rst/')

  header_comment > $out_file

  cat $f | \
  use_marketing_name | \
  pandoc \
    --from gfm \
    --to rst \
    --standalone \
    --reference-links \
    --columns=1300 | \
   convert_doc_extensions | \
   convert_relative_links | \
   strip_needless_header_refs | \
   convert_overview_links \
     >> $out_file

  if [[ $out_file =~ monitor-config.rst$ ]]; then
    cat <<EOH >> $out_file

.. toctree::
   :glob:
   :hidden:
   :maxdepth: 1

   ./monitors/*
EOH
  fi

  if [[ $out_file =~ observer-config.rst$ ]]; then
    cat <<EOH >> $out_file

.. toctree::
   :glob:
   :hidden:
   :maxdepth: 1

   ./observers/*
EOH
  fi

done

header_comment | \
  cat - $AGENT_REPO_BASE/README.md | \
    use_marketing_name | \
    sed -e 's/# SignalFx Smart Agent/# Overview/' | \
    sed -e '/GoDoc/d' | \
    sed -e '/CircleCI/d' | \
    pandoc --from gfm --to rst --standalone --reference-links --wrap none | \
    convert_doc_extensions | \
    convert_relative_links \
      > $AGENT_PRODUCT_DOCS/overview.rst

# Make sure we can build the project in sphinx
make -C $AGENT_PRODUCT_DOCS html