-- t-paliad-161: Inline Paliadin chat modal + agent-suggested write path.
--
-- Design: docs/design-paliadin-inline-2026-05-08.md §7.1 + §4.2.
--
-- Two coordinated additions:
--
-- 1. paliad.approval_requests gets two new columns marking which requests
--    were drafted by Paliadin on a user's behalf:
--      - requester_kind text — 'user' (direct create) | 'agent' (Paliadin
--                              suggestion awaiting the user's review)
--      - agent_turn_id  uuid — links back to the paliadin_turns row that
--                              produced the suggestion. ON DELETE SET NULL
--                              so audit rows survive turn-row purges.
--    The xor-check pins (kind='agent' ↔ agent_turn_id IS NOT NULL) so we
--    can't lose provenance on agent rows or accidentally tag user rows
--    with a turn id.
--
-- 2. paliad.paliadin_turns.context jsonb — the structured page-context
--    payload (route_name + primary_entity_type + primary_entity_id +
--    user_selection_text + view hints) the inline widget submits with
--    every turn. Old page_origin column stays as the cosmetic URL field.
--
-- Idempotent — every ALTER uses IF NOT EXISTS and the constraints/index
-- are guarded by DO blocks. Re-applying after a partial failure leaves
-- the same end state as a fresh run.

-- ============================================================================
-- 1. paliad.approval_requests.requester_kind + agent_turn_id
-- ============================================================================

ALTER TABLE paliad.approval_requests
    ADD COLUMN IF NOT EXISTS requester_kind text NOT NULL DEFAULT 'user';

DO $$
BEGIN
    IF NOT EXISTS (
        SELECT 1 FROM pg_constraint
         WHERE conname = 'approval_requests_requester_kind_check'
           AND conrelid = 'paliad.approval_requests'::regclass
    ) THEN
        ALTER TABLE paliad.approval_requests
            ADD CONSTRAINT approval_requests_requester_kind_check
            CHECK (requester_kind IN ('user', 'agent'));
    END IF;
END$$;

ALTER TABLE paliad.approval_requests
    ADD COLUMN IF NOT EXISTS agent_turn_id uuid;

DO $$
BEGIN
    IF NOT EXISTS (
        SELECT 1 FROM pg_constraint
         WHERE conname = 'approval_requests_agent_turn_fk'
           AND conrelid = 'paliad.approval_requests'::regclass
    ) THEN
        ALTER TABLE paliad.approval_requests
            ADD CONSTRAINT approval_requests_agent_turn_fk
            FOREIGN KEY (agent_turn_id) REFERENCES paliad.paliadin_turns(turn_id)
            ON DELETE SET NULL;
    END IF;
END$$;

DO $$
BEGIN
    IF NOT EXISTS (
        SELECT 1 FROM pg_constraint
         WHERE conname = 'approval_requests_agent_xor'
           AND conrelid = 'paliad.approval_requests'::regclass
    ) THEN
        ALTER TABLE paliad.approval_requests
            ADD CONSTRAINT approval_requests_agent_xor
            CHECK (
                (requester_kind = 'agent' AND agent_turn_id IS NOT NULL)
             OR (requester_kind = 'user'  AND agent_turn_id IS NULL)
            );
    END IF;
END$$;

CREATE INDEX IF NOT EXISTS approval_requests_agent_turn_idx
    ON paliad.approval_requests (agent_turn_id)
    WHERE agent_turn_id IS NOT NULL;

COMMENT ON COLUMN paliad.approval_requests.requester_kind IS
    'Who originated the request: ''user'' (direct user create) or '
    '''agent'' (Paliadin drafted it from a chat turn, awaiting user '
    'approval). Default ''user'' so existing audit rows backfill cleanly.';

COMMENT ON COLUMN paliad.approval_requests.agent_turn_id IS
    'When requester_kind=''agent'', the paliadin_turns row the suggestion '
    'came from. NULL otherwise. ON DELETE SET NULL so the audit record '
    'survives if the turn row is later purged.';

-- ============================================================================
-- 2. paliad.paliadin_turns.context — structured page payload
-- ============================================================================

ALTER TABLE paliad.paliadin_turns
    ADD COLUMN IF NOT EXISTS context jsonb;

COMMENT ON COLUMN paliad.paliadin_turns.context IS
    'Structured page-context payload from the inline widget: route_name + '
    'primary_entity_type + primary_entity_id + user_selection_text + '
    'view_mode + filter_summary. NULL for legacy turns (PoC standalone '
    'page predates the structured payload — page_origin is the only field '
    'they carry). Design: docs/design-paliadin-inline-2026-05-08.md §4.';