# frozen_string_literal: true

require 'fileutils'
require 'shellwords'
require 'tmpdir'

# tool to write ArcGIS layer(s) to json or database output
# rubocop:disable Metrics/ClassLength
class LayerWriter
  attr_reader :type

  GDAL = /GDAL (\d+\.\d+\.\d+)/
  V1_11_4 = Gem::Version.new('1.11.4') # https://trac.osgeo.org/gdal/ticket/6529
  TABLES = "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'"
  TYPES = ['Group ', 'Feature ', 'Annotation ', 'Annotation Sub'].freeze
  CONN = %i[host port dbname user password].freeze
  GEOM_TYPES = { 'esriGeometryPoint' => 'POINT',
                 'esriGeometryMultipoint' => 'MULTIPOINT',
                 'esriGeometryLine' => 'LINESTRING',
                 'esriGeometryPolyline' => 'MULTILINESTRING',
                 'esriGeometryPolygon' => 'MULTIPOLYGON' }.freeze
  OGR = 'ogr2ogr -overwrite -f "PostgreSQL" PG:'

  def initialize(url:, path: nil, arcrest_opts: {})
    @url = url
    @output_path = output_path(path) || config_path
    @arcrest_opts = arcrest_opts
    @conn = conn
    @id = id
    @service_url = service_url
    @layer = layer
    @page_json = @layer.json
    @type = layer_type
    @name = name
  end

  def output_json
    output(:json)
  end

  def output_to_db
    raise 'ogr2ogr executable missing, is GDAL installed and in your PATH?' unless (v_string = ogr2ogr?)
    raise 'ogr2ogr version must be > 1.11.4' unless Gem::Version.new(v_string.match(GDAL)[1]) > V1_11_4

    output(:db)
  end

  private

  def conn
    CONN.zip(CONN.map { |key| GisScraper.config[key] }).to_h
  end

  def output(format)
    @type == 'Feature Layer' ? _method(format) : do_sub_layers(format) # recurses sub-layers
  end

  def _method(format)
    format == :db ? write_to_db : write_json
  end

  def output_path(path)
    File.expand_path(path) if path
  end

  def connection
    PG.connect @conn
  end

  def ogr2ogr?
    `ogr2ogr --version`
  rescue Errno::ENOENT
    nil
  end

  def config_path
    File.expand_path GisScraper.config[:output_path]
  end

  def service_url
    @url.split('/')[0..-2].join('/')
  end

  def id
    @url.split('/').last
  end

  def layer
    ArcREST::Layer.new(@url, @arcrest_opts)
  end

  def layer_type
    validate_layer @page_json['type']
  end

  def validate_layer(type)
    raise "Bad Layer type: #{type}" unless TYPES.any? { |t| type == "#{t}Layer" }

    type
  end

  def name
    @page_json['name'].tr('/', '_') # make Postgres-safe
  end

  def sub_layer_ids
    @page_json['subLayers'].map { |hash| hash['id'] } || []
  end

  def json_data
    FeatureScraper.new(url: "#{@service_url}/#{@id}", arcrest_opts: @arcrest_opts).json_data
  end

  def write_json
    File.write json_path, json_data
  end

  def json_path
    "#{@output_path}/#{@name}.json"
  end

  def write_to_db
    @output_path = Dir.mktmpdir('gis_scraper') # prefix for identification
    write_json
    `#{OGR}"#{conn_str}" "#{json_path}" -nln #{table} #{srs} -nlt #{pg_geom}`
  ensure
    FileUtils.remove_entry @output_path
  end

  def pg_geom
    GEOM_TYPES[geo] || raise("Unknown geom: '#{geo}' for layer #{@name}")
  end

  def geo
    @page_json['geometryType']
  end

  def srs
    return '' unless GisScraper.config[:srs]

    "-a_srs #{GisScraper.config[:srs]}" || ''
  end

  def tables
    connection.exec(TABLES).map { |tup| tup['table_name'] } # list of current db table names
  end

  def table
    table_name << table_suffix
  end

  def table_name
    Shellwords.escape(@name.downcase.tr(' ', '_')).prepend('_')
  end

  def table_suffix
    tables.any? { |t| t == table_name } ? '_' : ''
  end

  def conn_str
    host, port, db, user, pwd = *@conn.values
    "dbname='#{db}' host='#{host}' port='#{port}' user='#{user}' password='#{pwd}'"
  end

  def do_sub_layers(format)
    FileUtils.mkdir File.join(@output_path, @name) if format == :json
    path = @output_path << "/#{@name}"
    sub_layer_ids.each { |n| sub_layer(n, path).send(:output, format) }
  end

  def sub_layer(id, path)
    self.class.new(url: "#{@service_url}/#{id}", path: path, arcrest_opts: @arcrest_opts) # recurse
  end
end
# rubocop:enable Metrics/ClassLength