add generator

lib/michel/generators/michel_generator.rb

@@ -0,0 +1,162 @@
+class MichelGenerator < Rails::Generators::Base
+  def add_scenic_gem
+    puts "Adding scenic gem to Gemfile"
+    gem "scenic"
+    `bundle install`
+  end
+
+  def create_index_in_migration
+    puts "Generating bookings index migration"
+    generate "migration", "add_index_to_bookings"
+    Dir.glob("db/migrate/*add_index_to_bookings.rb").each do |file|
+      insert_into_file file, after: "def change" do
+        <<~RUBY
+          \nreversible do |direction|
+            direction.up do
+              execute <<-SQL
+                CREATE EXTENSION btree_gist;
+                CREATE INDEX on bookings using gist (resource_id, tsrange(start_time, start_time + interval '1 minute' * duration, '()'));
+              SQL
+            end
+            direction.down do
+              execute <<-SQL
+                DROP INDEX bookings_resource_id_tsrange_idx;
+                DROP EXTENSION IF EXISTS btree_gist;
+              SQL
+            end
+          end
+        RUBY
+      end
+    end
+  end
+
+  def create_scenic_model
+    puts "Creating scenic model available_time_slots"
+    generate "scenic:model", "available_time_slots", "--materialized"
+  end
+
+  def create_sql_file
+    puts "Creating materialized view SQL at db/views/available_time_slots_v01.sql"
+    insert_into_file "db/views/available_time_slots_v01.sql" do
+      <<~SQL
+        WITH RECURSIVE time_slots AS (
+          -- Generate a series of dates for the next year, starting from tomorrow
+          SELECT
+            p.id AS availability_id,
+            p.resource_id,
+            -- what is DATE_TRUNC?
+            -- DATE_TRUNC('week', CURRENT_DATE) returns the first day of the week
+            (DATE_TRUNC('week', CURRENT_DATE) + (p.weekday - 1 || ' days')::interval) AS start_date,
+            CURRENT_DATE + INTERVAL '6 months' AS end_date,
+            p.start_time,
+            p.end_time,
+            p.timezone
+          FROM
+            availabilities p
+          UNION ALL
+          -- Recursively generate dates for all instances of the given weekday
+          SELECT
+            ts.availability_id,
+            ts.resource_id,
+            ts.start_date + INTERVAL '1 week' AS start_date,  -- Explicitly alias the column
+            ts.end_date,
+            ts.start_time,
+            ts.end_time,
+            ts.timezone
+          FROM
+            time_slots ts
+          WHERE
+            ts.start_date + INTERVAL '1 week' <= ts.end_date
+        ),
+        -- Generate time slots for each day, every 15 minutes
+        slot_intervals AS (
+          SELECT
+            ts.availability_id,
+            ts.resource_id,
+            ts.start_date,
+
+            -- Create proper timestamps for start and end times with timezone handling
+            (make_timestamptz(
+              date_part('year', ts.start_date)::integer,
+              date_part('month', ts.start_date)::integer,
+              date_part('day', ts.start_date)::integer,
+              split_part(ts.start_time, ':', 1)::int,
+              split_part(ts.start_time, ':', 2)::int,
+              0,
+              ts.timezone
+            )) AT TIME ZONE 'UTC' AS slot_start_time,
+
+            (make_timestamptz(
+              date_part('year', ts.start_date)::integer,
+              date_part('month', ts.start_date)::integer,
+              date_part('day', ts.start_date)::integer,
+              split_part(ts.end_time, ':', 1)::int,
+              split_part(ts.end_time, ':', 2)::int,
+              0,
+              ts.timezone
+            )) AT TIME ZONE 'UTC' AS slot_end_time
+          FROM
+            time_slots ts
+        ),
+        time_slots_every_15_min AS (
+          SELECT
+            si.availability_id,
+            si.resource_id,
+            si.start_date,
+
+            -- Generate the series for time slots every 15 minutes
+            generate_series(
+              GREATEST(si.slot_start_time, CURRENT_DATE + INTERVAL '1 day'),
+              -- Ensure it starts from tomorrow
+              si.slot_end_time - INTERVAL '30 minutes',
+              INTERVAL '15 minutes'
+            ) AS slot_start_time
+          FROM
+            slot_intervals si
+        )
+        SELECT
+          concat(availability_id, slot_start_time) AS id,
+          availability_id,
+          resource_id,
+          slot_start_time as start_time,
+          slot_start_time + INTERVAL '30 minutes' AS end_time
+        FROM
+          time_slots_every_15_min
+        EXCEPT
+                    SELECT
+                      concat(availability_id, slot_start_time) AS id,
+                      time_slots_every_15_min.availability_id,
+                      time_slots_every_15_min.resource_id,
+                      time_slots_every_15_min.slot_start_time as start_time,
+                      time_slots_every_15_min.slot_start_time + INTERVAL '30 minutes' AS end_time
+                    FROM       time_slots_every_15_min
+                    CROSS JOIN bookings
+                    WHERE      tsrange(bookings.start_time, bookings.start_time + interval '1 minute' * bookings.duration, '()')
+                              && tsrange(time_slots_every_15_min.slot_start_time, time_slots_every_15_min.slot_start_time + INTERVAL '30 minutes', '()')
+                    AND bookings.resource_id = time_slots_every_15_min.resource_id
+
+      SQL
+    end
+  end
+
+  def add_associations_to_models
+    insert_into_file "app/models/availability.rb", after: "class Availability < ApplicationRecord" do
+      <<~RUBY
+        \nhas_many :available_time_slots
+      RUBY
+    end
+
+    insert_into_file "app/models/available_time_slot.rb", after: "class AvailableTimeSlot < ApplicationRecord" do
+      <<~RUBY
+        \nbelongs_to :availability
+        \nbelongs_to :resource
+      RUBY
+    end
+
+    insert_into_file "app/models/resource.rb", after: "class Resource < ApplicationRecord" do
+      <<~RUBY
+        \nhas_many :available_time_slots
+      RUBY
+    end
+  end
+end