#!/usr/bin/env bash
# Usage: {script} DOCS_DIREECTORY
# Update list of rules and link related rules.

set -eo pipefail

declare -r IFS=$'\n'
declare -r DOCS_DIREECTORY="${1}"

declare -A RULES_BY_CATEGORIZATION=()
declare -A RELATED_RULES=()

list_rules()
{
  find "${DOCS_DIREECTORY}/rules" -type f |
    sed "s,${DOCS_DIREECTORY}/,," |
    cut -d '/' -f 2 |
    cut -d '.' -f 1 |
    sort
}

list_categories()
{
  while read rule; do
    declare filename="${DOCS_DIREECTORY}/rules/${rule}.md"
    sed -n '/## Categorization/,/## Changelog/p' "${filename}"
  done < <(list_rules) |
    grep '^-' |
    sort -u |
    sed 's,- ,,'
}

create_rule_documentation()
{
  # Usage: create_rule_documentation RULE RELATED_RULES
  local rule=${1}
  local related_rules=${2}
  local filename="${DOCS_DIREECTORY}/rules/${rule}.md"
  local links=$(ggrep -E '^\[.+\]: .+' "${filename}")
  local related_links=$(
    tr ':' '\n' <<< ${related_rules} |
      sort -u |
      grep -v '^$' |
      grep -v "^${rule}$" |
      sed -E "s,(.+),- [\1](\1.md),g"
  )

  # "Description" section
  sed -nE '/^# /,/^## Changelog/p' "${filename}" | ggrep -E -v '^## Changelog'

  # "Changelog" section
  sed -nE '/^## Changelog/,/^\*\*\*/p' "${filename}" | ggrep -Fv '***'

  # "See also" section
  echo "***"
  echo "See also:"
  echo
  echo "${related_links}"

  # Index of links
  if [[ ! -z "${links}" ]]; then
    echo
    echo "${links}"
  fi
}

create_list_of_rules()
{
  echo "Building list of rules per categorization"
  while read rule; do
    declare filename="${DOCS_DIREECTORY}/rules/${rule}.md"
    for category in $(sed -n '/## Categorization/,/## Changelog/p' "${filename}" |
                        grep '^-' |
                        sed 's,- ,,'); do
      RULES_BY_CATEGORIZATION[${category}]=${RULES_BY_CATEGORIZATION[${category}]}:${rule}
    done
  done < <(list_rules)

  echo "Creating list of rules"
  {
    echo "# List of rules by category"
    echo
    for category in $(list_categories); do
      echo "## ${category}"
      sed -E 's,:,\n- ,g' <<< "${RULES_BY_CATEGORIZATION[${category}]}" |
        sort -u |
        sed -E 's,- (.+),- [\1](rules/\1.md),'
      echo
    done

    echo "## Alphabetically"
    echo
    ls -1 "${DOCS_DIREECTORY}/rules/" | sort | sed -E 's,^(.+).md$,- [\1](rules/\1.md),'
  } > "${DOCS_DIREECTORY}/08-list-of-rules-by-category.md"
}

link_related_rules()
{
  local temporaty=$(mktemp)

  echo "Building list of related rules"
  for rule in $(list_rules); do
    declare filename="${DOCS_DIREECTORY}/rules/${rule}.md"
    declare related_rules=$(ggrep -E '\[.+\]\(.+\.md\)' "${filename}" |
                              sed -E 's,.*\[.+\]\((.+)\.md\).*,\1,' |
                              grep -v 'comparable-values')

    for related_rule in ${related_rules}; do
      RELATED_RULES[${related_rule}]=${RELATED_RULES[${related_rule}]}:${rule}
    done

    RELATED_RULES[${rule}]="${RELATED_RULES[${rule}]}:$(tr '\n' ':' <<< ${related_rules})"
  done

  echo "Recreating rule documentations with related rules"
  for rule in $(list_rules); do
    echo "- ${rule}"
    create_rule_documentation "${rule}" "${RELATED_RULES[${rule}]}" > "${temporaty}"
    cat "${temporaty}" > "${DOCS_DIREECTORY}/rules/${rule}.md"
  done
}

create_list_of_rules
link_related_rules