BEGIN;

ALTER TABLE conversation
    ADD COLUMN runtime_type varchar(32) NOT NULL DEFAULT 'legacy_voicechat'
    CHECK (runtime_type IN ('legacy_voicechat', 'volc_hardware_agent'));

CREATE INDEX conversation_runtime_status_idx
    ON conversation (runtime_type, status, created_at DESC);

CREATE TABLE hardware_agent_device_binding (
    id                  uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    public_id           uuid NOT NULL UNIQUE DEFAULT gen_random_uuid(),
    tenant_id           uuid NOT NULL REFERENCES tenant(id),
    device_id           uuid NOT NULL,
    provider            varchar(40) NOT NULL DEFAULT 'volcengine',
    product_key         varchar(200),
    provider_device_ref varchar(200),
    credential_ref      varchar(500),
    bot_id              varchar(200) NOT NULL,
    transport           varchar(32) NOT NULL DEFAULT 'high_quality'
                        CHECK (transport IN ('high_quality', 'low_load')),
    status              varchar(24) NOT NULL DEFAULT 'ACTIVE'
                        CHECK (status IN ('ACTIVE', 'DISABLED', 'REVOKED')),
    created_at          timestamptz NOT NULL DEFAULT now(),
    updated_at          timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT hardware_agent_binding_device_tenant_fk FOREIGN KEY (device_id, tenant_id)
        REFERENCES device (id, tenant_id),
    CONSTRAINT hardware_agent_binding_device_key UNIQUE (device_id)
);
CREATE INDEX hardware_agent_binding_tenant_status_idx
    ON hardware_agent_device_binding (tenant_id, status);

CREATE TABLE hardware_agent_session (
    id                       uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    public_id                uuid NOT NULL UNIQUE DEFAULT gen_random_uuid(),
    tenant_id                uuid NOT NULL REFERENCES tenant(id),
    conversation_id          uuid NOT NULL UNIQUE,
    provider                 varchar(40) NOT NULL DEFAULT 'volcengine',
    provider_session_ref     varchar(200) NOT NULL UNIQUE,
    bot_id                   varchar(200) NOT NULL,
    transport                varchar(32) NOT NULL
                             CHECK (transport IN ('high_quality', 'low_load')),
    session_nonce_digest     char(64) NOT NULL,
    config_digest            char(64) NOT NULL,
    status                   varchar(32) NOT NULL
                             CHECK (status IN ('READY', 'STARTING', 'ACTIVE', 'STOPPING', 'COMPLETED', 'FAILED', 'EXPIRED')),
    wait_for_session_update  boolean NOT NULL DEFAULT true,
    provider_started_at      timestamptz,
    provider_ended_at        timestamptz,
    last_event_at            timestamptz,
    last_event_sequence      bigint NOT NULL DEFAULT 0 CHECK (last_event_sequence >= 0),
    created_at               timestamptz NOT NULL DEFAULT now(),
    updated_at               timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT hardware_agent_session_conversation_tenant_fk FOREIGN KEY (conversation_id, tenant_id)
        REFERENCES conversation (id, tenant_id)
);
CREATE INDEX hardware_agent_session_tenant_status_idx
    ON hardware_agent_session (tenant_id, status, updated_at DESC);

CREATE TABLE hardware_agent_event (
    id                    uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id             uuid NOT NULL REFERENCES tenant(id),
    conversation_id       uuid NOT NULL,
    event_id              varchar(255) NOT NULL,
    sequence_no           bigint NOT NULL CHECK (sequence_no > 0),
    event_type            varchar(64) NOT NULL,
    occurred_at           timestamptz NOT NULL,
    payload_digest        char(64) NOT NULL,
    created_at            timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT hardware_agent_event_conversation_tenant_fk FOREIGN KEY (conversation_id, tenant_id)
        REFERENCES conversation (id, tenant_id),
    CONSTRAINT hardware_agent_event_key UNIQUE (tenant_id, event_id),
    CONSTRAINT hardware_agent_event_sequence_key UNIQUE (conversation_id, sequence_no)
);

COMMENT ON COLUMN conversation.runtime_type IS
    'legacy_voicechat uses platform-managed RTC/VoiceChat; volc_hardware_agent uses device-to-provider audio with platform control-plane sessions.';

COMMIT;