BEGIN;
CREATE TABLE canvas_ai_runs (
 project text NOT NULL,
 workspace_id uuid NOT NULL,
 board_id uuid NOT NULL,
 id uuid NOT NULL DEFAULT gen_random_uuid(),
 account_id uuid NOT NULL,
 idempotency_key uuid NOT NULL,
 payload_hash text NOT NULL,
 status text NOT NULL CHECK(status IN('queued','running','succeeded','partially_succeeded','failed','cancelled','conflict')),
 plan jsonb NOT NULL,
 create_response jsonb NOT NULL,
 error_code text,
 cancel_requested boolean NOT NULL DEFAULT false,
 lease_id uuid,
 lease_until timestamptz,
 last_seq bigint NOT NULL DEFAULT 0 CHECK(last_seq>=0),
 available_at timestamptz NOT NULL DEFAULT now(),
 created_at timestamptz NOT NULL DEFAULT now(),
 completed_at timestamptz,
 expires_at timestamptz NOT NULL DEFAULT now()+interval '30 days',
 PRIMARY KEY(project,workspace_id,id),
 UNIQUE(project,workspace_id,account_id,board_id,idempotency_key),
 FOREIGN KEY(project,workspace_id,board_id) REFERENCES materials ON DELETE RESTRICT,
 FOREIGN KEY(project,account_id) REFERENCES project_accounts
);
CREATE INDEX canvas_ai_pending ON canvas_ai_runs(available_at,created_at,id) WHERE status='queued';
CREATE INDEX canvas_ai_active ON canvas_ai_runs(project,workspace_id,board_id,created_at,id) WHERE status IN('queued','running');
CREATE TABLE canvas_ai_steps (
 project text NOT NULL,
 workspace_id uuid NOT NULL,
 run_id uuid NOT NULL,
 id text NOT NULL,
 board_id uuid NOT NULL,
 node_id text NOT NULL,
 ordinal integer NOT NULL CHECK(ordinal>=0),
 status text NOT NULL CHECK(status IN('queued','running','succeeded','failed','cancelled','conflict','skipped')),
 model_id text NOT NULL,
 frozen_input jsonb NOT NULL,
 target_fingerprint text NOT NULL,
 output jsonb,
 error_code text,
 applied_version bigint,
 started_at timestamptz,
 completed_at timestamptz,
 PRIMARY KEY(project,workspace_id,run_id,id),
 UNIQUE(project,workspace_id,run_id,board_id,node_id),
 FOREIGN KEY(project,workspace_id,run_id) REFERENCES canvas_ai_runs ON DELETE CASCADE,
 FOREIGN KEY(project,workspace_id,board_id) REFERENCES materials ON DELETE RESTRICT
);
CREATE UNIQUE INDEX canvas_ai_node_busy ON canvas_ai_steps(project,workspace_id,board_id,node_id) WHERE status IN('queued','running');
CREATE TABLE canvas_ai_events (
 project text NOT NULL,
 workspace_id uuid NOT NULL,
 run_id uuid NOT NULL,
 seq bigint NOT NULL CHECK(seq>0),
 type text NOT NULL,
 data jsonb NOT NULL,
 created_at timestamptz NOT NULL DEFAULT now(),
 PRIMARY KEY(project,workspace_id,run_id,seq),
 FOREIGN KEY(project,workspace_id,run_id) REFERENCES canvas_ai_runs ON DELETE CASCADE
);
-- Per-run serialization increments last_seq and inserts an event in one statement.
-- A lease which expires after a worker started is not automatically re-executed:
-- recovery marks the uncertain step failed, preventing duplicate model invocations.
CREATE TABLE canvas_ai_mutations (
 project text NOT NULL,
 workspace_id uuid NOT NULL,
 run_id uuid NOT NULL,
 account_id uuid NOT NULL,
 action text NOT NULL,
 idempotency_key uuid NOT NULL,
 payload_hash text NOT NULL,
 response_body jsonb NOT NULL,
 created_at timestamptz NOT NULL DEFAULT now(),
 PRIMARY KEY(project,workspace_id,run_id,account_id,action,idempotency_key),
 FOREIGN KEY(project,workspace_id,run_id) REFERENCES canvas_ai_runs ON DELETE CASCADE,
 FOREIGN KEY(project,account_id) REFERENCES project_accounts
);
COMMIT;