sure/lib/generators/provider/family/templates/importer.rb.tt

# frozen_string_literal: true

class <%= class_name %>Item::Importer
  include SyncStats::Collector
  include <%= class_name %>Account::DataHelpers
<% if investment_provider? -%>

  # Chunk size for fetching activities
  ACTIVITY_CHUNK_DAYS = 365
  MAX_ACTIVITY_CHUNKS = 3 # Up to 3 years of history

  # Minimum existing activities required before using incremental sync
  MINIMUM_HISTORY_FOR_INCREMENTAL = 10
<% end -%>

  attr_reader :<%= file_name %>_item, :<%= file_name %>_provider, :sync

  def initialize(<%= file_name %>_item, <%= file_name %>_provider:, sync: nil)
    @<%= file_name %>_item = <%= file_name %>_item
    @<%= file_name %>_provider = <%= file_name %>_provider
    @sync = sync
  end

  class CredentialsError < StandardError; end

  def import
    Rails.logger.info "<%= class_name %>Item::Importer - Starting import for item #{<%= file_name %>_item.id}"

    credentials = <%= file_name %>_item.<%= file_name %>_credentials
    unless credentials
      raise CredentialsError, "No <%= class_name %> credentials configured for item #{<%= file_name %>_item.id}"
    end

    # Step 1: Fetch and store all accounts
    import_accounts(credentials)

    # Step 2: For LINKED accounts only, fetch data
    # Unlinked accounts just need basic info (name, balance) for the setup modal
    linked_accounts = <%= class_name %>Account
      .where(<%= file_name %>_item_id: <%= file_name %>_item.id)
      .joins(:account_provider)

    Rails.logger.info "<%= class_name %>Item::Importer - Found #{linked_accounts.count} linked accounts to process"

    linked_accounts.each do |<%= file_name %>_account|
      Rails.logger.info "<%= class_name %>Item::Importer - Processing linked account #{<%= file_name %>_account.id}"
      import_account_data(<%= file_name %>_account, credentials)
    end

    # Update raw payload on the item
    <%= file_name %>_item.upsert_<%= file_name %>_snapshot!(stats)
  rescue Provider::<%= class_name %>::AuthenticationError => e
    <%= file_name %>_item.update!(status: :requires_update)
    raise
  end

  private

    def stats
      @stats ||= {}
    end

    def persist_stats!
      return unless sync&.respond_to?(:sync_stats)
      merged = (sync.sync_stats || {}).merge(stats)
      sync.update_columns(sync_stats: merged)
    end

    def import_accounts(credentials)
      Rails.logger.info "<%= class_name %>Item::Importer - Fetching accounts"

      # TODO: Implement API call to fetch accounts
      # accounts_data = <%= file_name %>_provider.list_accounts(...)
      accounts_data = []

      stats["api_requests"] = stats.fetch("api_requests", 0) + 1
      stats["total_accounts"] = accounts_data.size

      # Track upstream account IDs to detect removed accounts
      upstream_account_ids = []

      accounts_data.each do |account_data|
        begin
          import_account(account_data, credentials)
          # TODO: Extract account ID from your provider's response format
          # upstream_account_ids << account_data[:id].to_s if account_data[:id]
        rescue => e
          Rails.logger.error "<%= class_name %>Item::Importer - Failed to import account: #{e.message}"
          stats["accounts_skipped"] = stats.fetch("accounts_skipped", 0) + 1
          register_error(e, account_data: account_data)
        end
      end

      persist_stats!

      # Clean up accounts that no longer exist upstream
      prune_removed_accounts(upstream_account_ids)
    end

    def import_account(account_data, credentials)
      # TODO: Customize based on your provider's account ID field
      # <%= file_name %>_account_id = account_data[:id].to_s
      # return if <%= file_name %>_account_id.blank?

      # <%= file_name %>_account = <%= file_name %>_item.<%= file_name %>_accounts.find_or_initialize_by(
      #   <%= file_name %>_account_id: <%= file_name %>_account_id
      # )

      # Update from API data
      # <%= file_name %>_account.upsert_from_<%= file_name %>!(account_data)

      stats["accounts_imported"] = stats.fetch("accounts_imported", 0) + 1
    end

    def import_account_data(<%= file_name %>_account, credentials)
<% if investment_provider? -%>
      # Import holdings
      import_holdings(<%= file_name %>_account, credentials)

      # Import activities
      import_activities(<%= file_name %>_account, credentials)
<% else -%>
      # Import transactions
      import_transactions(<%= file_name %>_account, credentials)
<% end -%>
    end
<% if investment_provider? -%>

    def import_holdings(<%= file_name %>_account, credentials)
      Rails.logger.info "<%= class_name %>Item::Importer - Fetching holdings for account #{<%= file_name %>_account.id}"

      begin
        # TODO: Implement API call to fetch holdings
        # holdings_data = <%= file_name %>_provider.get_holdings(account_id: <%= file_name %>_account.<%= file_name %>_account_id)
        holdings_data = []

        stats["api_requests"] = stats.fetch("api_requests", 0) + 1

        if holdings_data.any?
          # Convert SDK objects to hashes for storage
          holdings_hashes = holdings_data.map { |h| sdk_object_to_hash(h) }
          <%= file_name %>_account.upsert_holdings_snapshot!(holdings_hashes)
          stats["holdings_found"] = stats.fetch("holdings_found", 0) + holdings_data.size
        end
      rescue => e
        Rails.logger.warn "<%= class_name %>Item::Importer - Failed to fetch holdings: #{e.message}"
        register_error(e, context: "holdings", account_id: <%= file_name %>_account.id)
      end
    end

    def import_activities(<%= file_name %>_account, credentials)
      Rails.logger.info "<%= class_name %>Item::Importer - Fetching activities for account #{<%= file_name %>_account.id}"

      begin
        # Determine date range
        start_date = calculate_start_date(<%= file_name %>_account)
        end_date = Date.current

        # TODO: Implement API call to fetch activities
        # activities_data = <%= file_name %>_provider.get_activities(
        #   account_id: <%= file_name %>_account.<%= file_name %>_account_id,
        #   start_date: start_date,
        #   end_date: end_date
        # )
        activities_data = []

        stats["api_requests"] = stats.fetch("api_requests", 0) + 1

        if activities_data.any?
          # Convert SDK objects to hashes and merge with existing
          activities_hashes = activities_data.map { |a| sdk_object_to_hash(a) }
          merged = merge_activities(<%= file_name %>_account.raw_activities_payload || [], activities_hashes)
          <%= file_name %>_account.upsert_activities_snapshot!(merged)
          stats["activities_found"] = stats.fetch("activities_found", 0) + activities_data.size
        elsif fresh_linked_account?(<%= file_name %>_account)
          # Fresh account with no activities - schedule background fetch
          schedule_background_activities_fetch(<%= file_name %>_account, start_date)
        end
      rescue => e
        Rails.logger.warn "<%= class_name %>Item::Importer - Failed to fetch activities: #{e.message}"
        register_error(e, context: "activities", account_id: <%= file_name %>_account.id)
      end
    end

    def calculate_start_date(<%= file_name %>_account)
      # Use user-specified start date if available
      user_start = <%= file_name %>_account.sync_start_date
      return user_start if user_start.present?

      # For accounts with existing history, use incremental sync
      existing_count = (<%= file_name %>_account.raw_activities_payload || []).size
      if existing_count >= MINIMUM_HISTORY_FOR_INCREMENTAL && <%= file_name %>_account.last_activities_sync.present?
        # Incremental: go back 30 days from last sync to catch updates
        (<%= file_name %>_account.last_activities_sync - 30.days).to_date
      else
        # Full sync: go back up to 3 years
        (ACTIVITY_CHUNK_DAYS * MAX_ACTIVITY_CHUNKS).days.ago.to_date
      end
    end

    def fresh_linked_account?(<%= file_name %>_account)
      # Account was just linked and has no activity history yet
      <%= file_name %>_account.last_activities_sync.nil? &&
        (<%= file_name %>_account.raw_activities_payload || []).empty?
    end

    def schedule_background_activities_fetch(<%= file_name %>_account, start_date)
      return if <%= file_name %>_account.activities_fetch_pending?

      Rails.logger.info "<%= class_name %>Item::Importer - Scheduling background activities fetch for account #{<%= file_name %>_account.id}"

      <%= file_name %>_account.update!(activities_fetch_pending: true)
      <%= class_name %>ActivitiesFetchJob.perform_later(<%= file_name %>_account, start_date: start_date)
    end

    def merge_activities(existing, new_activities)
      # Merge by ID, preferring newer data
      by_id = {}
      existing.each { |a| by_id[activity_key(a)] = a }
      new_activities.each { |a| by_id[activity_key(a)] = a }
      by_id.values
    end

    def activity_key(activity)
      activity = activity.with_indifferent_access if activity.is_a?(Hash)
      # Use ID if available, otherwise generate key from date/type/amount
      activity[:id] || activity["id"] ||
        [ activity[:date], activity[:type], activity[:amount], activity[:symbol] ].join("-")
    end
<% else -%>

    def import_transactions(<%= file_name %>_account, credentials)
      Rails.logger.info "<%= class_name %>Item::Importer - Fetching transactions for account #{<%= file_name %>_account.id}"

      begin
        # Determine date range
        start_date = calculate_transaction_start_date(<%= file_name %>_account)
        end_date = Date.current

        # TODO: Implement API call to fetch transactions
        # transactions_data = <%= file_name %>_provider.get_transactions(
        #   account_id: <%= file_name %>_account.<%= file_name %>_account_id,
        #   start_date: start_date,
        #   end_date: end_date
        # )
        transactions_data = []

        stats["api_requests"] = stats.fetch("api_requests", 0) + 1

        if transactions_data.any?
          # Convert SDK objects to hashes and merge with existing
          transactions_hashes = transactions_data.map { |t| sdk_object_to_hash(t) }
          merged = merge_transactions(<%= file_name %>_account.raw_transactions_payload || [], transactions_hashes)
          <%= file_name %>_account.upsert_<%= file_name %>_transactions_snapshot!(merged)
          stats["transactions_found"] = stats.fetch("transactions_found", 0) + transactions_data.size
        end
      rescue => e
        Rails.logger.warn "<%= class_name %>Item::Importer - Failed to fetch transactions: #{e.message}"
        register_error(e, context: "transactions", account_id: <%= file_name %>_account.id)
      end
    end

    def calculate_transaction_start_date(<%= file_name %>_account)
      # Use user-specified start date if available
      user_start = <%= file_name %>_account.sync_start_date
      return user_start if user_start.present?

      # For accounts with existing transactions, use incremental sync
      existing_count = (<%= file_name %>_account.raw_transactions_payload || []).size
      if existing_count >= 10 && <%= file_name %>_item.last_synced_at.present?
        # Incremental: go back 7 days from last sync to catch updates
        (<%= file_name %>_item.last_synced_at - 7.days).to_date
      else
        # Full sync: go back 90 days
        90.days.ago.to_date
      end
    end

    def merge_transactions(existing, new_transactions)
      # Merge by ID, preferring newer data
      by_id = {}
      existing.each { |t| by_id[transaction_key(t)] = t }
      new_transactions.each { |t| by_id[transaction_key(t)] = t }
      by_id.values
    end

    def transaction_key(transaction)
      transaction = transaction.with_indifferent_access if transaction.is_a?(Hash)
      # Use ID if available, otherwise generate key from date/amount/description
      transaction[:id] || transaction["id"] ||
        [ transaction[:date], transaction[:amount], transaction[:description] ].join("-")
    end
<% end -%>

    def prune_removed_accounts(upstream_account_ids)
      return if upstream_account_ids.empty?

      # Find accounts that exist locally but not upstream
      removed = <%= file_name %>_item.<%= file_name %>_accounts
        .where.not(<%= file_name %>_account_id: upstream_account_ids)

      if removed.any?
        Rails.logger.info "<%= class_name %>Item::Importer - Pruning #{removed.count} removed accounts"
        removed.destroy_all
      end
    end

    def register_error(error, **context)
      stats["errors"] ||= []
      stats["errors"] << {
        message: error.message,
        context: context.to_s,
        timestamp: Time.current.iso8601
      }
    end
end