#!/bin/bash
# Copyright 2019 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Documentation
### create markdown docs for fx subcommands

## usage: fx helpdoc [OPTIONS] OUTPUT_PATH
##
## Create markdown documentation for fx and its subcommands, based on
## the same metadata that is used to create the output of `fx help`
##
##     --vendor                  create docs for subcommands in //vendor/*/scripts/devshell.
##                                 If specified, only vendor docs are documented. There's
##                                 no way to generate docs for vendor and non-vendor at the
##                                 same time.
##     --toc-prefix URL_PREFIX   use URL_PREFIX instead of "/reference/tools/fx"
##                                 as an URL prefix in generated _toc.yaml files.
##     --escape-jinja            escape jinja tags in fx help text to avoid
##                                 parsing errors in fuchsia.dev.
##     --no-deprecated           do not create docs for deprecated subcommands
##     --no-contrib              do not create docs for contrib scripts in //tools/devshell/contrib/*
##     --archive                 creates a compressed archive at OUTPUT_PATH.
##                                 If specified, output will be compressed
##                                 and OUTPUT_PATH must end with .tgz or .tar.gz.
##                                 This must be the last option specified before the OUTPUT_PATH
##     --depfile DEPFILENAME     creates a depfile for helpdoc generation. Must be run with archive

# The generated documentation is laid out with all commands in /cmd/<cmd>.md is to make the URL predictable and stable. Categories
# are arbitrary texts and used to change often, it is undesirable that a category change invalidates the previous command help URL.
# Since the table of contents for each category needs to be in a file named _toc.yaml, these files are generated in the per-category
# directory along with a README.md, which links to the markdown in ../cmd.

# shellcheck disable=SC1091
source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?

categories=()

function main {
  show_vendor=0
  show_contrib=1
  escape_jinja=0
  show_deprecated=1
  archive_output=0
  archive_path=
  toc_prefix="/reference/tools/fx"
  create_depfile=0
  while [[ $# -ne 0 ]]; do
    case $1 in
      --vendor)
        show_vendor=1
        ;;
      --toc-prefix)
        if [[ $# -lt 2 ]]; then
          fx-error "Invalid syntax"
          fx-command-help
          exit 1
        fi
        shift
        toc_prefix="$1"
        ;;
      --depfile)
        if [[ $# -lt 2 ]]; then
          fx-error "Invalid syntax"
          fx-command-help
          exit 1
        fi
        shift
        depfile_prefix="$1"
        create_depfile=1
        ;;
      --no-deprecated)
        show_deprecated=0
        ;;
      --escape-jinja)
        escape_jinja=1
        ;;
      --no-contrib)
        show_contrib=0
        ;;
      --archive)
        archive_output=1
        ;;
      -*)
        fx-error "Unknown argument $1"
        fx-command-help
        exit 1
        ;;
      *)
        break
        ;;
    esac
    shift
  done

  if [[ $# -ne 1 ]]; then
    fx-error "No output path specified"
    fx-command-help
    return 1
  fi

  base_out="$1"
  if [[ "${archive_output}" -eq 1 ]]; then
    if [[ $base_out != *.tgz ]] && [[ $base_out != *.tar.gz ]]; then
          fx-error "OUTPUT_PATH must end with .tgz or .tar.gz if the archive flag is specified: ${base_out}"
          fx-command-help
          exit 1
    fi
    archive_path="$base_out"
    base_out="$(mktemp -d)"

    temp_dir="$base_out"
    base_out="${base_out}/helpdoc"
    mkdir "$base_out"
    trap 'cleanup' ERR INT TERM EXIT
  fi

  if [[ "${create_depfile}" -eq 1 ]]; then
          if [[ "${archive_output}" -eq 0 ]]; then
            fx-error "depfile currently not supported without archive_output"
            fx-command-help
            exit 1
          fi
   # This creates the depfile without quoting the archive_path or any of
   # the dependencies labels/filenames. According to the MAKEFILE documentation
   # which defines the format of depfiles, it is not clear if quoting will correctly
   # deal with special characters, vs. using \ to escape them.
    initial_deps="${archive_path}:  ../../scripts/fx ../../scripts/fx-help.awk
${archive_path}:  ../../tools/devshell/lib/fx-cmd-locator.sh ../../tools/devshell/lib/vars.sh
${archive_path}:  ../../tools/devshell/lib/fx-optional-features.sh ../../tools/devshell/lib/metrics.sh
${archive_path}:  ../../tools/devshell/lib/platform.sh "
    echo -n "$initial_deps" >> "${depfile_prefix}"
    for vendor_dir in "${FUCHSIA_DIR}"/vendor/*/scripts/devshell; do
      for d in "${vendor_dir}"/*; do
          echo "vendor file ${d}"
          if [[ "${d}" != *"/*" ]]; then
            rel_path="$(realpath_relative_to_pwd "${d}")"
            printf %s "${rel_path} " >> "${depfile_prefix}"
          fi
      done
    done
  fi

  # Make the cmd subdirectory to hold the per-command generated markdown.
  mkdir -p "${base_out}/cmd"

  # initializes the main index.md
  {
    echo "# fx - Fuchsia development commands"
    echo
    echo "\`fx\` is the entry-point for a set of subcommands that make many tasks related to Fuchsia development easier."
    echo
    echo "It contains a large number of subcommands. Run \`fx help\` to see all the available subcommands."
    echo "If you use bash or zsh as a shell, source \`scripts/fx-env.sh\`  "
    echo "to get some auto-completion."
    echo
    echo "Also see the [global options and flags](fx.md) that affect all subcommands."
    echo
    echo "# fx subcommands"

  } > "${base_out}/index.md"

  {
    echo "## fx command"
    echo
    echo "For help with specific subcommands, see [Overview page](index.md)."
    echo
    echo '```none'
    print-redacted-fx-help
    echo '```'
    echo
    echo "[fx source code](https://cs.opensource.google/fuchsia/fuchsia/+/main:scripts/fx)"
  } > "${base_out}/fx.md"

  if [[ "${show_vendor}" -eq 1 ]]; then
    for d in "${FUCHSIA_DIR}"/vendor/*/scripts/devshell; do
      if [[ -d "${d}" ]]; then
        vendor="${d%/scripts/devshell}"
        vendor="${vendor##*/}"
        {
          echo
          echo "## ${vendor} subcommands"
          echo
          _md_main_table_header
        } >> "${base_out}/index.md"
        handle-directory "${d}"
      fi
    done
  else
    {
      echo
      echo "## Main subcommands"
      echo
      echo "Subcommands that are part of the [fx workflow](/docs/development/build/fx.md)."
      echo
      _md_main_table_header
    } >> "${base_out}/index.md"
    handle-directory "${FUCHSIA_DIR}/tools/devshell"
    local d="${FUCHSIA_DIR}/tools/devshell/contrib"
    if [[ "${show_contrib}" -eq 1 && -d "${d}" ]]; then
      {
        echo
        echo "## Contrib subcommands"
        echo
        echo "Subcommands that have been contributed by project members that have other levels of support, ownership, or both."
        echo "The [OWNERS file](https://cs.opensource.google/fuchsia/fuchsia/+/main:tools/devshell/contrib/OWNERS) in the"
        echo "contrib directory provides a pointer to the member that supports each script."
        echo
        _md_main_table_header
      } >> "${base_out}/index.md"
      handle-directory "${d}"
    fi
  fi
  create-main-toc
  if [[ "${archive_output}" -eq 1 ]]; then
    tar -C "$temp_dir" -czvf "$archive_path" .
  fi

}

function realpath_relative_to_pwd {
  local path="$1" rp source target

  source="${PWD}"
  target="${path}"
  back=
  common_part="${source}"
  # shellcheck disable=SC2295
  while [[ "${target#$common_part}" == "${target}" ]]; do
    common_part="$(dirname "${common_part}")"
    back="../${back}"
  done
  # shellcheck disable=SC2295
  rp="${back}${target#$common_part/}"
  echo "${rp}"
}

function cleanup {
  if [[ -d "$temp_dir" ]]; then
    rm -Rf "$temp_dir"
  fi
}

function _md_main_table_header {
  echo "Command | Category | Description"
  echo "------- | -------- | -----------"
}

function print-redacted-fx-help {
  local filter
  filter="$(mktemp)"
  cat > "${filter}" <<EOF
  NR==1 || NR==3, /^$/ {
    print
  }

  /^[^ ].*help flags.*:/,/^$/ {
    print
  }
  /^Global .*:/,/^$/ {
    print
  }
EOF
  "${FUCHSIA_DIR}"/scripts/fx help --full | awk -f "${filter}"
  rm "${filter}"
}

function handle-directory {
  local d files cmds

  d="$1"
  files=( "${d}"/* )
  cmds=()

  for f in "${files[@]}"; do
    if [[ "${create_depfile}" -eq 1 ]]; then
      rel_path="$(realpath_relative_to_pwd "${f}")"
      printf %s "${rel_path} " >> "${depfile_prefix}"
    fi

    if [[ -f "${f}" && ( -x "${f}" || "${f: -3}" == ".fx" ) ]]; then
      cmds+=( "${f}" )
    fi
  done

  # sort cmds
  IFS=$'\n' sorted=($(sort <<< "${cmds[*]}"))
  unset IFS

  for c in "${sorted[@]}"; do
    echo "Processing $(basename "${c}")"
    handle-command "${c}"
  done
}


function normalize {
  local str="$1"
  echo "${str}" | tr -s ', .' '_' | tr '[:upper:]' '[:lower:]'
}

function get_binary_metadata {
  local file="$1"
  local key="$2"
  awk -F ' *= *' -f - "${file}" <<EOF
    /^#### +${key} */ {
      print 1;
    }
EOF
}

function get_metadata {
  local file="$1"
  local key="$2"
  awk -F ' *= *' -f - "${file}" <<EOF
    /^#### +${key} */ {
      print \$2;
    }
EOF
}

function get_metadata_camelcase {
  local file="$1"
  local key="$2"
  awk -F ' *= *' -f - "${file}" <<EOF
    /^#### +${key} */ {
      print toupper(substr(\$2,1,1)) tolower(substr(\$2,2));
    }
EOF
}

function get_summary {
  local cmd_path="$1"
  sed -n '1,/^### /s/^### //p' < "${cmd_path}" | sed 's/_/\\_/g; s/*/\\*/g; s/|/\\|/g'
}

function create-main-toc {
  # initializes the global toc
  {
    echo "toc:"
    echo "- title: Overview"
    echo "  path: ${toc_prefix}/index.md"
    echo "- title: fx command"
    echo "  path: ${toc_prefix}/fx.md"
  } > "${base_out}/_toc.yaml"

  # sort categories
  IFS=$'\n' sorted=($(sort -u <<< "${categories[*]}"))
  unset IFS

  for category in "${sorted[@]}"; do
    local norm_cat

    echo "Processing category ${category}"
    norm_cat="$(normalize "${category}")"
    # Make the category sub-dir to hold the toc.
    mkdir -p "${base_out}/${norm_cat}"
    # Appends the category to the global _toc.yaml
    {
      echo "- title: \"${category} commands\""
      echo "  path: ${toc_prefix}/${norm_cat}/README.md"
      echo "  section:"
      echo "  - include: ${toc_prefix}/${norm_cat}/_toc.yaml"
    } >> "${base_out}/_toc.yaml"
  done
}

function get-category-title {
  local category="$1"
  if [[ -n "${vendor}" ]]; then
    echo "${category} fx subcommands for ${vendor}"
  else
    echo "${category} fx subcommands"
  fi
}

function maybe-add-category {
  local cat_base category norm_cat toc
  category="$1"
  norm_cat="$(normalize "${category}")"
  cat_base="${base_out}/${norm_cat}/README.md"
  toc="${base_out}/${norm_cat}/_toc.yaml"
  # Make the category sub-dir to hold the toc.
  mkdir -p "${base_out}/${norm_cat}"
  if [[ ! -f "${toc}" ]]; then
    # initializes the per-category _toc.yaml
    {
      echo "toc:"
    } > "${toc}"

    # initializes the per-category index
    {
      echo "# $(get-category-title "${category}")"
      echo
      echo "Command | Description"
      echo "------- | -----------"
    } > "${cat_base}"
  fi
  echo "${norm_cat}"
}

function escape-jinja {
  # the way fuchsia.dev processes jinja tags is complicated, so simple escaping
  # techniques like {% verbatim %} or {{ '{' }} don't work, and since the help
  # text for these commands are in a fenced block, regular html escaping also
  # doesn't work. The "hack" below mixes jinja escaping with html escaping in
  # order to avoid errors with the fuchsia.dev parser.
  sed "s/{%/{{ '{\&ZeroWidthSpace;%' }}/g"
}

function handle-command {
  local category cat_url cmd_name cmd_path cmd_url deprecated deprecated_str filename norm_cat rel_path summary

  cmd_path="$1"
  cmd_name="$(basename "${cmd_path}" ".fx")"

  category="$(get_metadata_camelcase "${cmd_path}" "CATEGORY")"
   if [[ -z "${category}" ]]; then
    category="Other"
  fi

  norm_cat="$(maybe-add-category "${category}")"

  # categories is a global list.
  categories+=( "${category}" )

  # filename is the name of the generated markdown for this command.
  filename="${base_out}/cmd/${cmd_name}.md"
  deprecated_str=""
  deprecated="$(get_binary_metadata "${cmd_path}" "DEPRECATED")"

  if [[ "${deprecated}" -eq 1 ]]; then
    if [[ "${show_deprecated}" -eq 0 ]]; then
      return
    fi
    deprecated_str="DEPRECATED! "
  fi

  summary="${deprecated_str}$(get_summary "${cmd_path}")"
  cmd_url="cmd/${cmd_name}.md"
  cat_url="${norm_cat}/README.md"
  rel_path="${cmd_path#"${FUCHSIA_DIR}"/}"

  # Creates the per-command markdown file
  {
    if [[ -n "${vendor}" ]]; then
      echo "# ${deprecated_str}fx vendor ${vendor} ${cmd_name}"
    else
      echo "# ${deprecated_str}fx ${cmd_name}"
    fi
    echo ""
    echo "${summary}"
    echo
    echo '```none'
    fx-print-command-help "$cmd_path" |
      ( [[ ${escape_jinja} -eq 0 ]] && cat || escape-jinja )
    echo '```'
    if [[ -z "${vendor}" ]]; then
      echo
      echo "[${cmd_name} source code](https://cs.opensource.google/fuchsia/fuchsia/+/main:${rel_path})"
    fi
  } > "${filename}"

  # Appends the command to the per-category index
  {
    echo "[${cmd_name}](../${cmd_url}) | ${summary}"
  } >> "${base_out}/${norm_cat}/README.md"

  # Appends the command to the global index
  {
    echo "[${cmd_name}](${cmd_url}) | [${category}](${cat_url}) | ${summary}"
  } >> "${base_out}/index.md"

  # Appends the command to the per-category _toc.yaml
  {
    echo "- title: \"${deprecated_str}${cmd_name}\""
    echo "  path: ${toc_prefix}/${cmd_url}"
  } >> "${base_out}/${norm_cat}/_toc.yaml"

}

main "$@"