CREATE TABLE spaces (
  id          uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  slug        text NOT NULL UNIQUE,
  name        text NOT NULL,
  description text,
  theme       text,
  created_at  timestamptz NOT NULL DEFAULT now(),
  updated_at  timestamptz NOT NULL DEFAULT now()
);

CREATE TABLE projects (
  id           uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  space_id     uuid NOT NULL REFERENCES spaces(id) ON DELETE CASCADE,
  slug         text NOT NULL,
  name         text NOT NULL,
  description  text,
  status       text NOT NULL DEFAULT 'active'
               CHECK (status IN ('idea','active','paused','done','abandoned')),
  started_at   timestamptz,
  completed_at timestamptz,
  created_at   timestamptz NOT NULL DEFAULT now(),
  updated_at   timestamptz NOT NULL DEFAULT now(),
  UNIQUE (space_id, slug)
);

CREATE TABLE tasks (
  id           uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  space_id     uuid NOT NULL REFERENCES spaces(id) ON DELETE CASCADE,
  project_id   uuid REFERENCES projects(id) ON DELETE SET NULL,
  title        text NOT NULL,
  body         text,
  status       text NOT NULL DEFAULT 'todo'
               CHECK (status IN ('todo','doing','blocked','done')),
  priority     int,
  due_at       timestamptz,
  position     int,
  completed_at timestamptz,
  created_at   timestamptz NOT NULL DEFAULT now(),
  updated_at   timestamptz NOT NULL DEFAULT now()
);

CREATE INDEX idx_projects_space ON projects(space_id);
CREATE INDEX idx_tasks_space ON tasks(space_id);
CREATE INDEX idx_tasks_project ON tasks(project_id);
CREATE INDEX idx_tasks_status ON tasks(status) WHERE status <> 'done';