ALTER TABLE aibridge_token_usages
    ADD COLUMN cache_read_input_tokens BIGINT NOT NULL DEFAULT 0,
    ADD COLUMN cache_write_input_tokens BIGINT NOT NULL DEFAULT 0;

-- Backfill from metadata JSONB. Old rows stored cache tokens under
-- provider-specific keys; new rows use the dedicated columns above.
UPDATE aibridge_token_usages
SET

    -- Cache-read metadata keys by provider:
    --   Anthropic (/v1/messages):          "cache_read_input"
    --   OpenAI    (/v1/responses):         "input_cached"
    --   OpenAI    (/v1/chat/completions):  "prompt_cached"
    cache_read_input_tokens = GREATEST(
        COALESCE((metadata->>'cache_read_input')::bigint, 0),
        COALESCE((metadata->>'input_cached')::bigint, 0),
        COALESCE((metadata->>'prompt_cached')::bigint, 0)
    ),

	-- Cache-write metadata keys by provider:
	--   Anthropic (/v1/messages):          "cache_creation_input"
	--   OpenAI does not report cache-write tokens.
    cache_write_input_tokens = COALESCE((metadata->>'cache_creation_input')::bigint, 0)
WHERE metadata IS NOT NULL
  AND cache_read_input_tokens = 0
  AND cache_write_input_tokens = 0;