#!/usr/bin/env bash
#
# Copyright 2021 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Disable expansion
set -f

script_dir="$(dirname "$(realpath -e "${BASH_SOURCE[0]}")")"
readonly script_dir

# Print usage string
usage() {
    echo "Usage: $(basename "$0") [options] <title> <proto> <output>"
    echo
    echo "Generate an SVG rendering of the protobuffer schema and embed"
    echo "it in a static html page for documentation."
    echo
    echo "Arguments:"
    echo "   title - Title for output HTML page"
    echo "   proto - Path to protobuffer to generate SVG output for"
    echo "  output - Output filename (relative to script directory)"
    echo
    echo "Options:"
    echo "  --select/-s - Alternate select string to pass to protodot"
}

# Check that a binary with a given name exists.
checkbin_exists() {
    type "$1" &> /dev/null
}

# Convert a file into a data url
make_data_url() {
    mimetype=$(file -bN --mime-type "$1")
    content=$(base64 -w0 < "$1")
    echo "data:$mimetype;base64,$content"
}

if ! checkbin_exists "protodot"; then
    echo "Protodot not found, please install and add to PATH"
    exit 1
fi

# Parse options
select=""
while [[ $# -gt 0 ]]; do
    case $1 in
        --select|-s)
            select=$2
            shift 2
            ;;
        *)
            break
            ;;
    esac
done

if [[ $# -lt 3 ]]; then
    (
        echo "Error, not enough arguments."
        usage
    ) >&2
    exit 1
fi

# Get arguments
title=$1
proto=$2
output=$3

cd "${script_dir}" || exit 1

# Generate SVG output
cmd=(protodot -src "${proto}" -inc "$(realpath "${script_dir}/../proto")")
if [[ -n "${select}" ]]; then
    cmd+=(-select "${select}")
fi

# tee >(cat 1>&2) |
file=$(${cmd[*]} | grep "creating file" | cut -d: -f2 | xargs echo)

# Encode SVG to a data url and write it to a scratch file that we'll clean up.
make_data_url "${file}.svg" > __data.url
trap "rm -f __data.url" EXIT

# Copy template to output location and replace template fields.
cp "template/index.html" "${output}"
sed -i "s/{{TITLE}}/${title}/g" "${output}"
sed -i "s/{{DATE}}/$(date -u +%Y-%m-%d)/g" "${output}"

python - <<EOF
dataurl = open("__data.url").read().strip()
lines = [line.replace("{{DATA_URL}}", dataurl)
         for line in open("${output}").readlines()]

open("${output}", "w").writelines(lines)
EOF