-- P014: fills a real, previously-undiscovered gap in the migration chain.
-- sql/004_iceberg_write_boundary.sql's own comment already documented (but
-- did not fix) that `opt_dataset_iceberg_mappings.dataset_id REFERENCES
-- opt_datasets (dataset_id)` points at a table NO sql/ file ever defined --
-- meaning `psql -d opt < sql/001... < sql/002... < sql/004...` (exactly the
-- flow docs/runbook/backup-restore.md's own "Målbild" describes, and exactly
-- what a real restore drill executes) has never actually been runnable
-- end to end. This was found by running that exact sequence for real against
-- a throwaway Postgres container during P014's restore drill, not by
-- inspecting the code.
--
-- Numbered 003 (the previously-unused gap between 002_source_registry.sql
-- and 004_iceberg_write_boundary.sql) so the existing ordering -- 001 -> 002
-- -> 004 -> 005 -- becomes 001 -> 002 -> 003 -> 004 -> 005 without renumbering
-- anything already shipped.
--
-- Columns mirror src/services/dataset-service.ts's `DatasetRecord` exactly
-- (that file's own doc comment: "Storage shape: nullable columns, exactly as
-- the eventual `opt_datasets` table would hold them") -- this is the real
-- application contract, not a guess. `dataset_type`/`status` CHECK
-- constraints mirror src/types/dataset.ts's `DatasetType`/`DatasetStatus`
-- unions verbatim. DatasetService itself remains in-memory-only in this
-- pass (wiring it to this table is a separate, larger change than closing
-- the migration-chain gap); this table exists so the SCHEMA a fresh
-- database gets by replaying sql/*.sql matches what 004/005 already assume.

CREATE TABLE IF NOT EXISTS opt_datasets (
  dataset_id TEXT PRIMARY KEY,
  tenant_id TEXT NOT NULL,
  project_id TEXT NOT NULL,
  name TEXT NOT NULL,
  dataset_type TEXT NOT NULL CHECK (dataset_type IN ('raw', 'structured', 'enriched', 'curated', 'feature', 'derived')),
  status TEXT NOT NULL DEFAULT 'active' CHECK (status IN ('active', 'archived', 'deprecated')),
  description TEXT,
  correlation_id TEXT,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
  updated_at TIMESTAMPTZ,
  created_by TEXT
);

CREATE INDEX IF NOT EXISTS opt_datasets_tenant_project_idx ON opt_datasets (tenant_id, project_id);