-- Phase 12 (TASK-0121 + TASK-0125): AI usage-ledger + re-embed-walk indexes.
--
-- ai_messages IS the usage ledger (TASK-0121): the monthly token rollup
-- sums tokensIn + tokensOut per workspace since month-start → the
-- createdAt range index (plus the composite conversation range for
-- per-conversation history scans).
--
-- ai_embeddings gets [workspaceId, model] for the nightly full re-embed
-- walk (TASK-0125): the job groups rows by model before re-embedding.
--
-- No tables added/removed; no column changes (workspace.usageLimits /
-- workspace.settings are pre-existing Json columns).

CREATE INDEX "ai_messages_createdAt_idx" ON "ai_messages"("createdAt");
CREATE INDEX "ai_messages_conversationId_createdAt_idx" ON "ai_messages"("conversationId", "createdAt");
CREATE INDEX "ai_embeddings_workspaceId_model_idx" ON "ai_embeddings"("workspaceId", "model");

-- TASK-0122: conversation soft delete (hide immediately, purge after 30 d).
ALTER TABLE "ai_conversations" ADD COLUMN "deletedAt" TIMESTAMP(3);
CREATE INDEX "ai_conversations_deletedAt_idx" ON "ai_conversations"("deletedAt");

-- TASK-0121/0123+: per-message metadata (feature tag on hidden per-call
-- ledger rows, truncated flag on aborted streams, …).
ALTER TABLE "ai_messages" ADD COLUMN "metadata" JSONB;