-- +goose Up
SET @bases_exists := (
  SELECT COUNT(*)
  FROM information_schema.tables
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
);

SET @col_default_shift_start_exists := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
    AND column_name = 'default_shift_start'
);

SET @col_default_shift_end_exists := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
    AND column_name = 'default_shift_end'
);

SET @backfill_default_shift_start_sql := IF(
  @bases_exists > 0 AND @col_default_shift_start_exists > 0,
  "UPDATE bases SET default_shift_start = '06:00:00' WHERE default_shift_start IS NULL",
  'SELECT 1'
);
PREPARE stmt_backfill_default_shift_start FROM @backfill_default_shift_start_sql;
EXECUTE stmt_backfill_default_shift_start;
DEALLOCATE PREPARE stmt_backfill_default_shift_start;

SET @backfill_default_shift_end_sql := IF(
  @bases_exists > 0 AND @col_default_shift_end_exists > 0,
  "UPDATE bases SET default_shift_end = '21:00:00' WHERE default_shift_end IS NULL",
  'SELECT 1'
);
PREPARE stmt_backfill_default_shift_end FROM @backfill_default_shift_end_sql;
EXECUTE stmt_backfill_default_shift_end;
DEALLOCATE PREPARE stmt_backfill_default_shift_end;

SET @modify_default_shift_start_sql := IF(
  @bases_exists > 0 AND @col_default_shift_start_exists > 0,
  'ALTER TABLE bases MODIFY COLUMN default_shift_start TIME NOT NULL',
  'SELECT 1'
);
PREPARE stmt_modify_default_shift_start FROM @modify_default_shift_start_sql;
EXECUTE stmt_modify_default_shift_start;
DEALLOCATE PREPARE stmt_modify_default_shift_start;

SET @modify_default_shift_end_sql := IF(
  @bases_exists > 0 AND @col_default_shift_end_exists > 0,
  'ALTER TABLE bases MODIFY COLUMN default_shift_end TIME NOT NULL',
  'SELECT 1'
);
PREPARE stmt_modify_default_shift_end FROM @modify_default_shift_end_sql;
EXECUTE stmt_modify_default_shift_end;
DEALLOCATE PREPARE stmt_modify_default_shift_end;

-- +goose Down
SET @bases_exists := (
  SELECT COUNT(*)
  FROM information_schema.tables
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
);

SET @col_default_shift_start_exists := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
    AND column_name = 'default_shift_start'
);

SET @col_default_shift_end_exists := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'bases'
    AND column_name = 'default_shift_end'
);

SET @modify_default_shift_start_sql := IF(
  @bases_exists > 0 AND @col_default_shift_start_exists > 0,
  'ALTER TABLE bases MODIFY COLUMN default_shift_start TIME NULL',
  'SELECT 1'
);
PREPARE stmt_modify_default_shift_start_down FROM @modify_default_shift_start_sql;
EXECUTE stmt_modify_default_shift_start_down;
DEALLOCATE PREPARE stmt_modify_default_shift_start_down;

SET @modify_default_shift_end_sql := IF(
  @bases_exists > 0 AND @col_default_shift_end_exists > 0,
  'ALTER TABLE bases MODIFY COLUMN default_shift_end TIME NULL',
  'SELECT 1'
);
PREPARE stmt_modify_default_shift_end_down FROM @modify_default_shift_end_sql;
EXECUTE stmt_modify_default_shift_end_down;
DEALLOCATE PREPARE stmt_modify_default_shift_end_down;