# Script for populating the database. You can run it as:
#
#     mix run priv/repo/seeds.exs
#
# Inside the script, you can read and write to any of your
# repositories directly:
#
#     ActionRequestsDemo.Repo.insert!(%ActionRequestsDemo.SomeSchema{})
#
# We recommend using the bang functions (`insert!`, `update!`
# and so on) as they will fail if something goes wrong.

alias ActionRequestsDemo.Repo
alias ActionRequestsDemo.ActionRequests.ActionRequest

# Configuration
total_records = 1_000_000
# SQLite has a max parameter limit of 32766
# With 7 fields per record, max is ~4681 records per batch
# Using 4000 to be safe
batch_size = 4_000
num_batches = div(total_records, batch_size)

IO.puts("Seeding #{total_records} action requests in #{num_batches} batches of #{batch_size}...")
IO.puts("Started at: #{DateTime.utc_now()}")

statuses = ["resolved", "unresolved"]

# Helper function to generate a single record
generate_record = fn ->
  patient_name = Faker.Person.name()
  status = Enum.random(statuses)
  assigned_user_id = if :rand.uniform() > 0.3, do: Enum.random(1..5), else: nil
  days_ago = :rand.uniform(365)

  inserted_at =
    DateTime.utc_now()
    |> DateTime.add(-days_ago * 24 * 3600, :second)
    |> DateTime.truncate(:second)

  delivery_scheduled_at =
    if :rand.uniform() > 0.4 do
      days_ahead = :rand.uniform(14)

      NaiveDateTime.utc_now()
      |> NaiveDateTime.add(days_ahead * 24 * 3600, :second)
      |> NaiveDateTime.truncate(:second)
    else
      nil
    end

  %{
    id: Ecto.UUID.generate(),
    patient_name: patient_name,
    status: status,
    assigned_user_id: assigned_user_id,
    delivery_scheduled_at: delivery_scheduled_at,
    inserted_at: inserted_at,
    updated_at: inserted_at
  }
end

# Process batches sequentially (SQLite doesn't handle concurrent writes well)
start_time = System.monotonic_time(:millisecond)

Enum.each(1..num_batches, fn batch_num ->
  # Generate batch of records
  records = for _i <- 1..batch_size, do: generate_record.()

  # Insert batch in a single transaction
  {count, _} = Repo.insert_all(ActionRequest, records)

  if rem(batch_num, 10) == 0 do
    elapsed = div(System.monotonic_time(:millisecond) - start_time, 1000)
    progress = batch_num * batch_size
    rate = if elapsed > 0, do: div(progress, elapsed), else: 0
    IO.puts("Progress: #{progress}/#{total_records} (#{div(progress * 100, total_records)}%) - #{rate} records/sec")
  end

  count
end)

end_time = System.monotonic_time(:millisecond)
elapsed_seconds = div(end_time - start_time, 1000)
records_per_second = div(total_records, max(elapsed_seconds, 1))

IO.puts("\n✓ Successfully seeded #{total_records} action requests!")
IO.puts("Total time: #{elapsed_seconds} seconds (#{records_per_second} records/sec)")
IO.puts("Finished at: #{DateTime.utc_now()}")