Feature: Checkpoint Operations for Resume Functionality
  As a data engineer
  I want to save and retrieve checkpoint data
  So that I can resume processing from where it left off

  Background:
    Given an authenticated sheets tracker
    And a sheet with the following datasets
      | Dataset Name | Status      | Error | Last Shard | Total Rows | Skip Descriptions | Last Updated |
      | wordnet      | IN PROGRESS |       | 5          | 1000       | 50                | 2026-01-30   |
      | yago         | NOT STARTED |       |            |            |                   |              |

  Scenario: Get checkpoint data for dataset with checkpoint
    When I get checkpoint for "wordnet"
    Then the checkpoint should contain last_completed_shard 5
    And the checkpoint should contain total_rows 1000
    And the checkpoint should contain skip_descriptions 50
    And the checkpoint should contain timestamp "2026-01-30"

  Scenario: Get checkpoint for dataset without checkpoint data
    When I get checkpoint for "yago"
    Then the checkpoint should be empty or None

  Scenario: Get checkpoint for non-existent dataset
    When I get checkpoint for "nonexistent"
    Then the checkpoint should be None

  Scenario: Get checkpoint when tracker not authenticated
    Given an unauthenticated sheets tracker
    When I get checkpoint for "wordnet"
    Then the checkpoint should be None

  Scenario: Update checkpoint data for existing dataset
    When I update checkpoint for "yago" with shard 3, rows 500, descriptions 25
    Then the update should succeed
    When I get checkpoint for "yago"
    Then the checkpoint should contain last_completed_shard 3
    And the checkpoint should contain total_rows 500
    And the checkpoint should contain skip_descriptions 25
    And the checkpoint should have timestamp

  Scenario: Update checkpoint for non-existent dataset
    When I update checkpoint for "nonexistent" with shard 1, rows 100, descriptions 10
    Then the update should return False

  Scenario: Update checkpoint when tracker not authenticated
    Given an unauthenticated sheets tracker
    When I update checkpoint for "wordnet" with shard 10, rows 2000, descriptions 100
    Then the update should return False

  Scenario: Checkpoint columns with alternate names
    Given a sheet with headers "Dataset Name, Status, Error, Last Completed Shard, Total Rows, Skip Descriptions, Last Updated"
    And a sheet with the following datasets
      | Dataset Name | Status      | Error | Last Completed Shard | Total Rows | Skip Descriptions | Last Updated |
      | wordnet      | IN PROGRESS |       | 10                   | 5000       | 250               | 2026-01-30   |
    When the tracker loads headers
    Then last_shard_col should be identified correctly
    And total_rows_col should be identified correctly
    And skip_descriptions_col should be identified correctly
    And last_updated_col should be identified correctly

  Scenario: Checkpoint with missing columns
    Given a sheet with headers "Dataset Name, Status, Error, Last Shard"
    And a sheet with the following datasets
      | Dataset Name | Status      | Error | Last Shard |
      | wordnet      | IN PROGRESS |       | 7          |
    When I get checkpoint for "wordnet"
    Then the checkpoint should contain last_completed_shard 7
    And the checkpoint should not contain total_rows
    And the checkpoint should not contain skip_descriptions

  Scenario: Update checkpoint with only some columns present
    Given a sheet with headers "Dataset Name, Status, Last Shard, Total Rows"
    And a sheet with the following datasets
      | Dataset Name | Status      | Last Shard | Total Rows |
      | wordnet      | IN PROGRESS | 2          | 200        |
    When I update checkpoint for "wordnet" with shard 5, rows 500, descriptions 50
    Then the update should succeed
    And only last_shard and total_rows should be updated

  Scenario: Checkpoint with empty values
    Given a sheet with the following datasets
      | Dataset Name | Status      | Error | Last Shard | Total Rows | Skip Descriptions |
      | wordnet      | IN PROGRESS |       |            |            |                   |
    When I get checkpoint for "wordnet"
    Then the checkpoint values should default to 0

  Scenario: Update checkpoint automatically sets timestamp
    Given a sheet with headers "Dataset Name, Status, Last Updated"
    And a sheet with the following datasets
      | Dataset Name | Status      | Last Updated |
      | wordnet      | IN PROGRESS |              |
    When I update checkpoint for "wordnet" with shard 1, rows 100, descriptions 10
    Then the last_updated column should be populated with current timestamp