-- The inbox becomes global to a user rather than per-project: a card now
-- either belongs to nobody's project (project_id AND status_id both NULL --
-- sitting in that user's inbox) or to exactly one project with a status in it
-- (both set). Cards also gain a direct owner_id, since inbox cards have no
-- project to derive ownership from.
--
-- SQLite can't relax an existing NOT NULL / add a CHECK to a live column, so
-- the table is rebuilt.

CREATE TABLE cards_new (
    id         INTEGER PRIMARY KEY AUTOINCREMENT,
    owner_id   INTEGER NOT NULL REFERENCES users (id) ON DELETE CASCADE,
    project_id INTEGER NULL REFERENCES projects (id) ON DELETE CASCADE,
    -- Was ON DELETE SET NULL; now that a project card must have a status
    -- (the CHECK below), silently nulling status_id on a deleted status would
    -- leave project_id orphaned without it. There is no status-delete
    -- endpoint yet, so this is only a safety net.
    status_id  INTEGER NULL REFERENCES card_statuses (id) ON DELETE RESTRICT,
    text       TEXT NOT NULL,
    complete   INTEGER NOT NULL DEFAULT 0 CHECK (complete IN (0, 1)),
    position   INTEGER NOT NULL DEFAULT 0,
    created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
    updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
    CHECK ((project_id IS NULL) = (status_id IS NULL))
);

-- Existing cards with no status were sitting in their project's old
-- per-project inbox column; that concept is gone, so they move to the (now
-- global, per-owner) inbox -- project_id cleared alongside status_id.
INSERT INTO cards_new (id, owner_id, project_id, status_id, text, complete, position, created_at, updated_at)
SELECT c.id,
       p.owner_id,
       CASE WHEN c.status_id IS NULL THEN NULL ELSE c.project_id END,
       c.status_id,
       c.text, c.complete, c.position, c.created_at, c.updated_at
FROM cards c
JOIN projects p ON p.id = c.project_id;

DROP TABLE cards;
ALTER TABLE cards_new RENAME TO cards;

CREATE INDEX idx_cards_owner_project_status_position
    ON cards (owner_id, project_id, status_id, position);
CREATE INDEX idx_cards_status ON cards (status_id);

-- Re-pack every column -- including each owner's inbox -- to a dense 0..n-1,
-- preserving relative order. Safe despite writing the table it reads: the CTE
-- is evaluated against the pre-update snapshot.
WITH ranked (id, rk) AS (
    SELECT id,
           row_number() OVER (
               PARTITION BY owner_id, project_id, status_id
               ORDER BY position, id
           ) - 1
    FROM cards
)
UPDATE cards
SET position = (SELECT rk FROM ranked WHERE ranked.id = cards.id);