#!/usr/bin/ruby

require 'optparse'
require 'yaml'
require 'fileutils'
require 'pathname'

@options = {}

@bitness = {
  'i386' => 32,
  'amd64' => 64,
}

def system!(cmd)
  system(cmd) or raise "failed to run #{cmd}"
end

def sanitize(str, where)
  raise "unsanitary string in #{where}" if (str =~ /[^\w.-]/)
  str
end

def sanitize_path(str, where)
  raise "unsanitary string in #{where}" if (str =~ /[^\w\/.-]/)
  str
end

def info(str)
  puts str unless @options[:quiet]
end

def build_one_configuration(suite, arch, build_desc, reference_datetime)
  bits = @bitness[arch] or raise "unknown architecture ${arch}"
  suitearch = "#{suite}-#{arch}"

  info "Stopping target if it is up"
  system "stop-target"

  sleep 1

  unless @options[:skip_image]
    info "Making a new image copy"
    system! "cp base-#{suitearch}.qcow2 target-#{suitearch}.qcow2"
  end

  info "Starting target"
  system! "start-target #{bits} #{suitearch}&"

  $stdout.write "Checking if target is up"

  (1..10).each do
    system "on-target true 2> /dev/null" and break
    sleep 2
    $stdout.write '.'
  end

  info ''

  system! "on-target true"

  info "Preparing build environment"
  system! "on-target bash < target-bin/init-build.sh"

  build_desc["files"].each do |filename|
    filename = sanitize(filename, "files section")
    system! "cd inputs && copy-to-target #{filename} build/"
  end

  info "Updating apt-get repository (log in var/install.log)"
  system! "on-target -u root apt-get update > var/install.log 2>&1"

  info "Installing additional packages (log in var/install.log)"
  system! "on-target -u root apt-get -y install #{build_desc["packages"].join(" ")} > var/install.log 2>&1"

  info "Grabbing package manifest"
  system! "on-target -u root bash < target-bin/grab-packages.sh > var/base-#{suitearch}.manifest"

  info "Creating build script (var/build-script)"

  File.open("var/build-script", "w") do |script|
    script.puts "#!/bin/bash"
    script.puts "set -e"
    script.puts "export OUTDIR=$HOME/out"
    script.puts "GBUILD_BITS=#{bits}"
    script.puts "MAKEOPTS=(-j2)"
    (ref_date, ref_time) = reference_datetime.split
    script.puts "REFERENCE_DATETIME='#{reference_datetime}'"
    script.puts "REFERENCE_DATE='#{ref_date}'"
    script.puts "REFERENCE_TIME='#{ref_time}'"
    script.puts
    build_desc["remotes"].each do |remote|
      script.puts "git clone -q #{remote["url"]} build/#{remote["dir"]}"
      script.puts "(cd build/#{remote["dir"]} && git checkout -q #{remote["commit"]})"
    end
    script.puts "cd build"
    script.puts build_desc["script"]
  end

  info "Running build script (log in var/build.log)"
  system! "on-target bash < var/build-script > var/build.log 2>&1"
end

################################

OptionParser.new do |opts|
  opts.banner = "Usage: build [options] <build-description>.yml"

  opts.on("-i", "--skip-image", "reuse current target image") do |v|
    @options[:skip_image] = v
  end
  opts.on("-q", "--quiet", "be quiet") do |v|
    @options[:quiet] = v
  end
  opts.on("-c PAIRS", "--commit PAIRS", "comma separated list of DIRECTORY=COMMIT pairs") do |v|
    @options[:commit] = v
  end
end.parse!

base_dir = Pathname.new(__FILE__).expand_path.dirname.parent
libexec_dir = base_dir + 'libexec'

ENV['PATH'] = libexec_dir.to_s + ":" + ENV['PATH']
ENV['GITIAN_BASE'] = base_dir.to_s

build_desc_file = ARGV.shift or raise "must supply YAML build description file"

build_desc = YAML.load_file(build_desc_file)

in_sums = []

build_dir = 'build'
result_dir = 'result'

FileUtils.rm_rf(build_dir)
FileUtils.mkdir(build_dir)
FileUtils.mkdir_p(result_dir)

package_name = build_desc["name"] or raise "must supply name"
package_name = sanitize(package_name, "package name")

suites = build_desc["suites"] or raise "must supply suites"
archs = build_desc["architectures"] or raise "must supply architectures"
reference_datetime = build_desc["reference_datetime"] or raise "must supply reference_datetime"

desc_sum = `sha256sum #{build_desc_file}`
desc_sum = desc_sum.sub(build_desc_file, "#{package_name}-desc.yml")
in_sums << desc_sum

build_desc["files"].each do |filename|
  filename = sanitize(filename, "files section")
  in_sums << `cd inputs && sha256sum #{filename}`
end

commits = {}

if @options[:commit]
  @options[:commit].split(',').each do |pair|
    (dir, commit) = pair.split('=')
    commits[dir] = commit
  end
end

build_desc["remotes"].each do |remote|
  if !remote["commit"]
    remote["commit"] = commits[remote["dir"]]
    raise "must specify a commit for directory #{remote["dir"]}" unless remote["commit"]
  end
end

base_manifests = YAML::Omap.new

suites.each do |suite|
  suite = sanitize(suite, "suite")
  archs.each do |arch|
    info "--- Building for #{suite} #{arch} ---"
    arch = sanitize(arch, "architecture")

    # Build!
    build_one_configuration(suite, arch, build_desc, reference_datetime)

    info "Grabbing results"
    system! "copy-from-target out #{build_dir}"

    base_manifest = File.read("var/base-#{suite}-#{arch}.manifest")
    base_manifests["#{suite}-#{arch}"] = base_manifest
  end
end

out_dir = File.join(build_dir, "out")
out_sums = {}

info "Generating report"
Dir.glob(File.join(out_dir, '**', '*'), File::FNM_DOTMATCH).sort.each do |file_in_out|
  next if File.directory?(file_in_out)
  file = file_in_out.sub(out_dir + File::SEPARATOR, '')
  file = sanitize_path(file, file_in_out)
  out_sums[file] = `cd #{out_dir} && sha256sum #{file}`
  raise "failed to sum #{file}" unless $? == 0
  puts out_sums[file] unless @options[:quiet]
end

out_manifest = out_sums.keys.sort.map { |key| out_sums[key] }.join('')

in_manifest = in_sums.join('')

# Use Omap to keep result deterministic
report = YAML::Omap[
  'out_manifest', out_manifest,
  'in_manifest', in_manifest,
  'base_manifests', base_manifests,
]

result_file = "#{package_name}-res.yml"
File.open(File.join(result_dir, result_file), "w") do |io|
  io.write report.to_yaml
end

system!("cd #{result_dir} && sha256sum #{result_file}") unless @options[:quiet]

info "Done."