CREATE TABLE IF NOT EXISTS user_channels (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  organization_id uuid NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
  channel_type text NOT NULL DEFAULT 'agentbus',
  display_name text NOT NULL,
  external_user_ref text,
  agentbus_ws_token_ciphertext text NOT NULL,
  agentbus_bot_address text,
  enabled boolean NOT NULL DEFAULT true,
  status text NOT NULL DEFAULT 'disabled',
  last_connected_at timestamptz,
  last_session_epoch bigint,
  last_error text,
  created_by uuid REFERENCES users(id) ON DELETE SET NULL,
  created_at timestamptz NOT NULL DEFAULT now(),
  updated_at timestamptz NOT NULL DEFAULT now(),
  CONSTRAINT user_channels_type_check CHECK (channel_type = 'agentbus'),
  CONSTRAINT user_channels_status_check CHECK (status IN ('disabled', 'connecting', 'connected', 'error')),
  UNIQUE (organization_id, display_name)
);

CREATE INDEX IF NOT EXISTS user_channels_enabled_idx
  ON user_channels (organization_id, enabled, updated_at DESC);

ALTER TABLE tasks
  ADD COLUMN IF NOT EXISTS channel_id uuid REFERENCES user_channels(id) ON DELETE SET NULL;

CREATE INDEX IF NOT EXISTS tasks_channel_idx
  ON tasks (organization_id, channel_id, created_at DESC);

CREATE TABLE IF NOT EXISTS agentbus_deliveries (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  organization_id uuid NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
  channel_id uuid NOT NULL REFERENCES user_channels(id) ON DELETE CASCADE,
  task_id uuid NOT NULL REFERENCES tasks(id) ON DELETE CASCADE,
  inbound_frame_id text NOT NULL,
  inbound_from text NOT NULL,
  conversation_id text,
  delivery_kind text NOT NULL,
  payload jsonb NOT NULL DEFAULT '{}'::jsonb,
  delivery_status text NOT NULL DEFAULT 'pending',
  attempt_count integer NOT NULL DEFAULT 0,
  next_attempt_at timestamptz NOT NULL DEFAULT now(),
  last_error text,
  delivered_at timestamptz,
  created_at timestamptz NOT NULL DEFAULT now(),
  updated_at timestamptz NOT NULL DEFAULT now(),
  CONSTRAINT agentbus_deliveries_kind_check CHECK (delivery_kind IN ('accepted', 'result')),
  CONSTRAINT agentbus_deliveries_status_check CHECK (delivery_status IN ('pending', 'sending', 'delivered', 'failed')),
  UNIQUE (channel_id, inbound_frame_id, delivery_kind)
);

CREATE INDEX IF NOT EXISTS agentbus_deliveries_pending_idx
  ON agentbus_deliveries (channel_id, delivery_status, next_attempt_at, created_at)
  WHERE delivery_status IN ('pending', 'sending', 'failed');

CREATE INDEX IF NOT EXISTS agentbus_deliveries_task_idx
  ON agentbus_deliveries (organization_id, task_id, delivery_kind, created_at);