Refactor GIAS commands into helper function

This will make it easier to create a scheduled Sidekiq job for this
task.

This also adds more comprehensive testing for these processes.

Jira-Issue: MAV-2788

Author: alistair-white-horne-tng

app/lib/gias.rb

@@ -0,0 +1,320 @@
+# frozen_string_literal: true
+
+module GIAS
+  class << self
+    def download(output_file:)
+      # 1. Go to https://get-information-schools.service.gov.uk/Downloads
+      # 2. Check "Establishment fields CSV"
+      # 3. Check "Establishment links CSV"
+      # 4. Submit
+      # 5. Download the zip file
+      # 6. Move the downloaded file to db/data/dfe-schools.zip
+
+      require "mechanize"
+
+      agent = Mechanize.new
+      agent.user_agent_alias = "Mac Safari"
+
+      page =
+        agent.get("https://get-information-schools.service.gov.uk/Downloads")
+      form = page.form_with(action: "/Downloads/Collate")
+      form.checkbox_with(id: "establishment-fields-csv-checkbox").check
+      form.checkbox_with(id: "establishment-links-csv-checkbox").check
+      download_page = form.submit
+
+      wait_time = 0
+      until (
+              download_form =
+                download_page.form_with(action: "/Downloads/Download/Extract")
+            ) || wait_time > 60
+        sleep(2)
+        wait_time += 2
+        download_page = agent.get(download_page.uri)
+      end
+
+      if download_form
+        download_button = download_form.button_with(value: "Results.zip")
+        download_file = agent.click(download_button)
+        download_file.save!(output_file)
+        true
+      else
+        false
+      end
+    end
+
+    def import(input_file:, progress_bar: nil)
+      open_csv(input_file) do |rows|
+        batch_size = 1000
+        schools = []
+
+        rows.each do |row|
+          gias_establishment_number = row["EstablishmentNumber"]
+          next if gias_establishment_number.blank?
+
+          schools << Location.new(
+            type: :school,
+            urn: row["URN"],
+            gias_local_authority_code: row["LA (code)"],
+            gias_establishment_number:,
+            gias_phase: Integer(row["PhaseOfEducation (code)"]),
+            gias_year_groups: process_year_groups(row),
+            name: row["EstablishmentName"],
+            address_line_1: row["Street"],
+            address_line_2: [
+              row["Locality"],
+              row["Address3"]
+            ].compact_blank.join(", "),
+            address_town: row["Town"],
+            address_postcode: row["Postcode"],
+            status: Integer(row["EstablishmentStatus (code)"]),
+            url: process_url(row["SchoolWebsite"].presence)
+          )
+
+          if schools.size >= batch_size
+            import_schools(schools)
+            update_sites(schools)
+            schools.clear
+          end
+
+          progress_bar&.increment
+        end
+
+        unless schools.empty?
+          import_schools(schools)
+          update_sites(schools)
+        end
+      end
+    end
+
+    def check_import(input_file:, progress_bar: nil)
+      schools_with_future_sessions = {
+        existing:
+          Set.new(
+            Location
+              .school
+              .joins(:sessions)
+              .merge(Session.scheduled)
+              .pluck(:urn)
+          ),
+        closed: {
+        },
+        closing: {
+        },
+        year_group_changes: {
+        }
+      }
+      schools_without_future_sessions = {
+        closed: {
+        },
+        closing: {
+        },
+        year_group_changes: {
+        }
+      }
+
+      existing_schools = Set.new(Location.school.pluck(:urn))
+      team_schools =
+        Set.new(
+          TeamLocation
+            .joins(:location)
+            .merge(Location.school)
+            .pluck(:"locations.urn")
+        )
+
+      new_schools = Set.new
+
+      Zip::File.open(input_file) do |zip|
+        links_csv = zip.glob("links_edubasealldata*.csv").first
+        links_csv_content = links_csv.get_input_stream.read
+
+        successors = {}
+        CSV.parse(
+          links_csv_content,
+          headers: true,
+          encoding: "ISO-8859-1:UTF-8"
+        ) do |row|
+          next unless row["LinkType"]&.include?("Successor")
+
+          successors[row["URN"]] ||= []
+          successors[row["URN"]] << row["LinkURN"]
+        end
+
+        school_data_csv = zip.glob("edubasealldata*.csv").first
+        school_csv_content = school_data_csv.get_input_stream.read
+
+        CSV.parse(
+          school_csv_content,
+          headers: true,
+          encoding: "ISO-8859-1:UTF-8"
+        ) do |row|
+          gias_establishment_number = row["EstablishmentNumber"]
+          next if gias_establishment_number.blank?
+
+          urn = row["URN"]
+          new_status = row["EstablishmentStatus (name)"]
+
+          if urn.in?(schools_with_future_sessions[:existing])
+            check_for_school_closure(
+              row,
+              schools_with_future_sessions,
+              successors
+            )
+            check_for_year_group_changes(
+              row,
+              schools_with_future_sessions,
+              existing_schools
+            )
+          elsif urn.in?(team_schools)
+            check_for_school_closure(
+              row,
+              schools_without_future_sessions,
+              successors
+            )
+            check_for_year_group_changes(
+              row,
+              schools_without_future_sessions,
+              existing_schools
+            )
+          elsif !urn.in?(existing_schools) &&
+                new_status.in?(["Open", "Open, but proposed to close"])
+            new_schools << urn
+          end
+        ensure
+          progress_bar&.increment
+        end
+      end
+
+      {
+        new_schools:,
+        schools_with_future_sessions:,
+        schools_without_future_sessions:
+      }
+    end
+
+    def process_url(url)
+      return nil if url.blank?
+
+      # Legh Vale school has a URL of http:www.leghvale.st-helens.sch.uk
+      # which is not a valid URL.
+      url = url.gsub("http:www", "http://www")
+
+      # Some school URLs don't start with http:// and https://
+      url.start_with?("http://", "https://") ? url : "https://#{url}"
+    end
+
+    def process_year_groups(row)
+      low_year_group = row["StatutoryLowAge"].to_i - 4
+      high_year_group = row["StatutoryHighAge"].to_i - 5
+      (low_year_group..high_year_group).to_a
+    end
+
+    def row_count(input_file)
+      Zip::File.open(input_file) do |zip|
+        csv_entry = zip.glob("edubasealldata*.csv").first
+        csv_entry.get_input_stream.read.lines.count
+      end
+    end
+
+    private
+
+    def open_csv(input_file)
+      Zip::File.open(input_file) do |zip|
+        csv_entry = zip.glob("edubasealldata*.csv").first
+        csv_content = csv_entry.get_input_stream.read
+        rows =
+          CSV.parse(csv_content, headers: true, encoding: "ISO-8859-1:UTF-8")
+        yield rows
+      end
+    end
+
+    def import_schools(schools)
+      Location.import!(
+        schools,
+        on_duplicate_key_update: {
+          conflict_target: %i[urn],
+          index_predicate: "site IS NULL",
+          columns: %i[
+            address_line_1
+            address_line_2
+            address_postcode
+            address_town
+            gias_establishment_number
+            gias_local_authority_code
+            gias_phase
+            gias_year_groups
+            name
+            status
+            url
+          ]
+        }
+      )
+    end
+
+    def update_sites(schools)
+      schools_by_urn = schools.index_by(&:urn)
+
+      sites =
+        Location
+          .where(urn: schools_by_urn.keys)
+          .where.not(site: nil)
+          .distinct
+          .map do |site|
+            school = schools_by_urn[site.urn]
+
+            site.assign_attributes(
+              gias_establishment_number: school.gias_establishment_number,
+              gias_local_authority_code: school.gias_local_authority_code,
+              gias_phase: school.gias_phase,
+              gias_year_groups: school.gias_year_groups,
+              status: school.status,
+              url: school.url
+            )
+
+            site
+          end
+
+      return if sites.empty?
+
+      Location.import!(
+        sites,
+        on_duplicate_key_update: {
+          conflict_target: %i[urn site],
+          columns: %i[
+            gias_establishment_number
+            gias_local_authority_code
+            gias_phase
+            gias_year_groups
+            status
+            url
+          ]
+        }
+      )
+    end
+
+    def check_for_school_closure(row, school_set, successors = {})
+      urn = row["URN"]
+      new_status = row["EstablishmentStatus (name)"]
+
+      if new_status == "Closed"
+        school_set[:closed][urn] = successors[urn] || []
+      elsif new_status == "Open, but proposed to close"
+        school_set[:closing][urn] = successors[urn] || []
+      end
+    end
+
+    def check_for_year_group_changes(row, school_set, existing_schools)
+      urn = row["URN"]
+      return unless urn.in? existing_schools
+
+      new_year_groups = process_year_groups(row)
+      current_year_groups = Location.school.find_by(urn:).gias_year_groups
+
+      if new_year_groups != current_year_groups
+        school_set[:year_group_changes][urn] = {
+          current: current_year_groups,
+          new: new_year_groups
+        }
+      end
+    end
+  end
+end