#!/bin/sh
# The source of this file is https://raw.githubusercontent.com/grafana/writers-toolkit/main/docs/make-docs.

set -ef

readonly DOCS_CONTAINER="${DOCS_CONTAINER:-make-docs}"
readonly DOCS_HOST_PORT="${DOCS_HOST_PORT:-3002}"
readonly DOCS_IMAGE="${DOCS_IMAGE:-grafana/docs-base:latest}"

readonly DOC_VALIDATOR_INCLUDE="${DOC_VALIDATOR_INCLUDE:-.+\.md$}"

readonly HUGO_REFLINKSERRORLEVEL="${HUGO_REFLINKSERRORLEVEL:-WARNING}"
readonly WEBSITE_EXEC="${WEBSITE_EXEC:-make server}"
# If set, the docs-base image will run a prebuild script that sets up Hugo mounts.
readonly WEBSITE_MOUNTS="${WEBSITE_MOUNTS:-}"

PODMAN="$(if command -v podman >/dev/null 2>&1; then echo podman; else echo docker; fi)"

about() {
  cat <<EOF
Test documentation locally with multiple source repositories.

The REPOS_PATH environment variable is a colon (:) separated list of paths in which to look for project repositories.
EOF
}

usage() {
  cat <<EOF
Usage:
  REPOS_PATH=<PATH[:<PATH>...]> $0 [<PROJECT>[:<VERSION>[:<REPO>[:<DIR>]]]...]

Examples:
  REPOS_PATH=~/ext/grafana/ $0 writers-toolkit tempo:latest helm-charts/mimir-distributed:latest:mimir:docs/sources/mimir-distributed
EOF
}

if [ $# -lt 1 ]; then
  cat <<EOF >&2
ERRR: arguments required but not supplied.

$(about)

$(usage)
EOF
  exit 1
fi

readonly REPOS_PATH="${REPOS_PATH:-$(realpath "$(git rev-parse --show-toplevel)/..")}"

if [ -z "${REPOS_PATH}" ]; then
  cat <<EOF >&2
ERRR: REPOS_PATH environment variable is required but has not been provided.

$(usage)
EOF
  exit 1
fi

SOURCES_as_code='as-code-docs'
SOURCES_enterprise_metrics='backend-enterprise'
SOURCES_enterprise_metrics_='backend-enterprise'
SOURCES_grafana_cloud='cloud-docs'
SOURCES_grafana_cloud_k6='k6-docs'
SOURCES_helm_charts_mimir_distributed='mimir'
SOURCES_helm_charts_tempo_distributed='tempo'
SOURCES_opentelemetry='opentelemetry-docs'

VERSIONS_as_code='UNVERSIONED'
VERSIONS_grafana_cloud='UNVERSIONED'
VERSIONS_grafana_cloud_k6='UNVERSIONED'
VERSIONS_opentelemetry='UNVERSIONED'
VERSIONS_technical_documentation='UNVERSIONED'
VERSIONS_writers_toolkit='UNVERSIONED'

PATHS_helm_charts_mimir_distributed='docs/sources/helm-charts/mimir-distributed'
PATHS_helm_charts_tempo_distributed='docs/sources/helm-charts/tempo-distributed'
PATHS_mimir='docs/sources/mimir'
PATHS_tempo='docs/sources/tempo'

# identifier STR
# Replace characters that are not valid in an identifier with underscores.
identifier() {
  echo "$1" | tr -C '[:alnum:]_\n' '_'
}

# aget ARRAY KEY
# Get the value of KEY from associative array ARRAY.
# Characters that are not valid in an identifier are replaced with underscores.
aget() {
  eval echo '$'"$(identifier "$1")_$(identifier "$2")"
}

# new_proj populates a new project structure.
new_proj() {
  _project="$1"
  _version="$2"
  _repo="$3"
  _path="$4"

  # If version is not set, use the script mapping of project to default versions if it exists.
  # Fallback to 'latest'.
  if [ -z "${_version}" ]; then
    if [ -z "$(aget VERSIONS "${_project}")" ]; then
      _version=latest
    else
      _version="$(aget VERSIONS "${_project}")"
    fi
  fi

  # If repo is not set, use the script mapping of project to repo name if it exists.
  # Fallback to using the project name.
  if [ -z "${_repo}" ]; then
    if [ -z "$(aget SOURCES "${_project}")" ]; then
      _repo="${_project}"
    else
      _repo="$(aget SOURCES "${_project}")"
    fi
  fi

  # If path is not set, use the script mapping of project to docs sources path if it exists.
  # Fallback to using 'docs/sources'.
  if [ -z "${_path}" ]; then
    if [ -z "$(aget PATHS "${_project}")" ]; then
      _path="docs/sources"
    else
      _path="$(aget PATHS "${_project}")"
    fi
  fi

  echo "${_project}:${_version}:${_repo}:${_path}"
  unset _project _version _repo _path
}

# proj_url returns the webserver URL for a project.
# It expects a complete project structure as input.
proj_url() {
  IFS=: read -r _project _version _ _ <<POSIX_HERESTRING
$1
POSIX_HERESTRING

  if [ -z "${_version}" ] || [ "${_version}" = 'UNVERSIONED' ]; then
    echo "http://localhost:${DOCS_HOST_PORT}/docs/${_project}/"
  else
    echo "http://localhost:${DOCS_HOST_PORT}/docs/${_project}/${_version}/"
  fi

  unset _project _version
}

# proj_ver returns the version for a project.
# It expects a complete project structure as input.
proj_ver() {
  IFS=: read -r _ _ver _ _ <<POSIX_HERESTRING
$1
POSIX_HERESTRING

  echo "${_ver}"
  unset _ver
}

# proj_dst returns the container path to content source for a project.
# It expects a complete project structure as input.
proj_dst() {
  IFS=: read -r _project _version _ _ <<POSIX_HERESTRING
$1
POSIX_HERESTRING

  if [ -z "${_version}" ] || [ "${_version}" = 'UNVERSIONED' ]; then
    echo "/hugo/content/docs/${_project}"
  else
    echo "/hugo/content/docs/${_project}/${_version}"
  fi
  unset _project _version
}

# proj_src returns the host path to content source for a project.
# It expects a complete project structure as input.
# It looks for the provided repository name in each of the paths specified in the REPOS_PATH environment variable.
proj_src() {
  IFS=: read -r _ _ _repo _path <<POSIX_HERESTRING
$1
POSIX_HERESTRING

  IFS=:
  for lookup in ${REPOS_PATH}; do
    if [ -d "${lookup}/${_repo}" ]; then
      echo "${lookup}/${_repo}/${_path}"
      unset _path _repo
      return
    fi
  done
  unset IFS

  echo "ERRR: could not find project '${_repo}' in any of the paths in REPOS_PATH '${REPOS_PATH}'." >&2
  echo "NOTE: you must have a checkout of the project '${_repo}' at '${REPOS_PATH##:*}/${_repo}'." >&2
  echo "NOTE: if you have cloned the repository into a directory with a different name, consider changing it to ${_repo}." >&2
  unset _path _repo
  exit 1
}

# proj_canonical returns the canonical absolute path partial URI for a project.
# It expects a complete project structure as input.
proj_canonical() {
  IFS=: read -r _project _version _ _ <<POSIX_HERESTRING
$1
POSIX_HERESTRING

  if [ -z "${_version}" ] || [ "${_version}" = 'UNVERSIONED' ]; then
    echo "/docs/${_project}"
  else
    echo "/docs/${_project}/${_version}"
  fi
  unset _project _version
}

proj_to_url_src_dst_ver() {
  _url="$(proj_url "$1")"
  _src="$(proj_src "$1")"
  _dst="$(proj_dst "$1")"
  _ver="$(proj_ver "$1")"

  echo "${_url}^${_src}^${_dst}^${_ver}"
  unset _url _src _dst _ver
}

url_src_dst_vers() {
  for arg in "$@"; do
    IFS=: read -r _project _version _repo _path <<POSIX_HERESTRING
$arg
POSIX_HERESTRING

    case "${_project}" in
      # Workaround for arbitrary mounts where the version field is expected to be the local directory
      # and the repo field is expected to be the container directory.
      arbitrary)
        echo "${_project}^${_version}^${_repo}^" # TODO
        ;;
      logs)
        proj_to_url_src_dst_ver "$(new_proj loki "${_version}")"
        proj_to_url_src_dst_ver "$(new_proj enterprise-logs "${_version}")"
        ;;
      metrics)
        proj_to_url_src_dst_ver "$(new_proj mimir "${_version}")"
        proj_to_url_src_dst_ver "$(new_proj helm-charts/mimir-distributed "${_version}")"
        proj_to_url_src_dst_ver "$(new_proj enterprise-metrics "${_version}")"
        ;;
      traces)
        proj_to_url_src_dst_ver "$(new_proj tempo "${_version}")"
        proj_to_url_src_dst_ver "$(new_proj enterprise-traces "${_version}")"
        ;;
      *)
        proj_to_url_src_dst_ver "$(new_proj "${_project}" "${_version}" "${_repo}" "${_path}")"
        ;;
    esac
  done

  unset _project _version _repo _path
}

url_src_dst_vers="$(url_src_dst_vers "$@")"

volumes=""
redirects=""

for x in ${url_src_dst_vers}; do
  IFS='^' read -r _url _src _dst _ver <<POSIX_HERESTRING
$x
POSIX_HERESTRING

  if [ "${_url}" != "arbitrary" ]; then
    if [ ! -f "${_src}/_index.md" ]; then
      echo "ERRR: Index file '${_src}/_index.md' does not exist." >&2
      echo "Is '${_src}' the correct source directory?" >&2
      exit 1
    fi
  fi

  echo "DEBG: Mounting '${_src}' at container path '${_dst}'" >&2
  if [ -z "${volumes}" ]; then
    volumes="--volume=${_src}:${_dst}"
  else
    volumes="${volumes} --volume=${_src}:${_dst}"
  fi

  if [ -n "${_ver}" ] && [ "${_ver}" != 'UNVERSIONED' ]; then
    if [ -z "${redirects}" ]; then
      redirects="${_dst}^${_ver}"
    else
      redirects="${redirects} ${_dst}^${_ver}"
    fi
  fi
  unset _url _src _dst _ver
done

IFS=':' read -r image _ <<POSIX_HERESTRING
${DOCS_IMAGE}
POSIX_HERESTRING

if [ "${image}" = "grafana/doc-validator" ]; then
  echo
  "${PODMAN}" run \
    --init \
    --interactive \
    --name "${DOCS_CONTAINER}" \
    --platform linux/amd64 \
    --rm \
    --tty \
    ${volumes} \
    "${DOCS_IMAGE}" \
    --skip-image-validation \
    --include="${DOC_VALIDATOR_INCLUDE}" \
    /hugo/content/docs \
    "$(proj_canonical "$(new_proj "$1")")"
else

  cat <<EOF >/tmp/make-docs-entrypoint
#!/usr/bin/env bash
for redirect in ${redirects}; do
  IFS='^' read -r path ver <<<"\${redirect}"
  echo -e "---\\nredirectURL: \"\${path/\/hugo\/content/}\"\\ntype: redirect\\n---\\n" > "\${path/\${ver}/_index.md}"

  if [[ -n "${WEBSITE_MOUNTS}" ]]; then
    unset WEBSITE_SKIP_MOUNTS
  fi
done

${WEBSITE_EXEC}
EOF
  chmod +x /tmp/make-docs-entrypoint
  volumes="${volumes} --volume=/tmp/make-docs-entrypoint:/entrypoint"
  readonly volumes

  echo
  echo "Documentation will be served at the following URLs:"
  for x in ${url_src_dst_vers}; do
    IFS='^' read -r url _ _ <<POSIX_HERESTRING
$x
POSIX_HERESTRING

    if [ -n "${url}" ]; then
      echo "  ${url}"
    fi
  done

  echo
  "${PODMAN}" run \
    --env "HUGO_REFLINKSERRORLEVEL=${HUGO_REFLINKSERRORLEVEL}" \
    --init \
    --interactive \
    --name "${DOCS_CONTAINER}" \
    --platform linux/amd64 \
    --publish "${DOCS_HOST_PORT}:3002" \
    --publish "3003:3003" \
    --rm \
    --tty \
    ${volumes} \
    "${DOCS_IMAGE}" \
    /entrypoint
fi