BEGIN;

CREATE TABLE billing_price_book (
    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),
    provider            varchar(40) NOT NULL CHECK (provider ~ '^[a-z][a-z0-9_.-]{1,39}$'),
    currency            char(3) NOT NULL CHECK (currency ~ '^[A-Z]{3}$'),
    version_no          integer NOT NULL CHECK (version_no>0),
    status              varchar(16) NOT NULL DEFAULT 'DRAFT' CHECK (status IN ('DRAFT','PUBLISHED','RETIRED')),
    source_ref          varchar(300) NOT NULL CHECK (length(trim(source_ref))>0),
    change_summary      varchar(500) NOT NULL CHECK (length(trim(change_summary))>0),
    effective_from      timestamptz NOT NULL,
    created_by          uuid NOT NULL,
    published_by        uuid,
    published_at        timestamptz,
    retired_at          timestamptz,
    row_version         bigint NOT NULL DEFAULT 1 CHECK (row_version>0),
    created_at          timestamptz NOT NULL DEFAULT now(),
    updated_at          timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT billing_price_book_creator_tenant_fk FOREIGN KEY (created_by,tenant_id) REFERENCES user_account(id,tenant_id),
    CONSTRAINT billing_price_book_publisher_tenant_fk FOREIGN KEY (published_by,tenant_id) REFERENCES user_account(id,tenant_id),
    CONSTRAINT billing_price_book_version_key UNIQUE (tenant_id,provider,version_no),
    CONSTRAINT billing_price_book_publish_state CHECK (
        (status='DRAFT' AND published_by IS NULL AND published_at IS NULL AND retired_at IS NULL) OR
        (status='PUBLISHED' AND published_by IS NOT NULL AND published_at IS NOT NULL AND retired_at IS NULL) OR
        (status='RETIRED' AND published_by IS NOT NULL AND published_at IS NOT NULL AND retired_at IS NOT NULL)
    )
);
CREATE UNIQUE INDEX billing_price_book_one_published ON billing_price_book(tenant_id,provider) WHERE status='PUBLISHED';

CREATE TABLE billing_price_rate (
    id                  uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    price_book_id       uuid NOT NULL REFERENCES billing_price_book(id) ON DELETE CASCADE,
    usage_category      varchar(32) NOT NULL CHECK (usage_category IN ('RTC','END_TO_END_VOICE','ASR','LLM','TTS','STORAGE','POST_PROCESSING')),
    metric_code         varchar(80) NOT NULL CHECK (metric_code ~ '^[a-z][a-z0-9_.-]{1,79}$'),
    unit                varchar(40) NOT NULL CHECK (unit ~ '^[a-z][a-z0-9_.-]{1,39}$'),
    unit_price_micros   bigint NOT NULL CHECK (unit_price_micros>=0),
    created_at          timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT billing_price_rate_key UNIQUE (price_book_id,usage_category,metric_code,unit)
);

CREATE TABLE usage_quota_policy (
    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),
    scope_type              varchar(16) NOT NULL CHECK (scope_type IN ('TENANT','DEVICE')),
    device_id               uuid,
    version_no              integer NOT NULL CHECK (version_no>0),
    status                  varchar(16) NOT NULL DEFAULT 'ACTIVE' CHECK (status IN ('ACTIVE','RETIRED')),
    billing_timezone        varchar(64) NOT NULL CHECK (length(trim(billing_timezone))>0),
    currency                char(3) NOT NULL CHECK (currency ~ '^[A-Z]{3}$'),
    daily_limit_micros      bigint NOT NULL CHECK (daily_limit_micros>0),
    monthly_limit_micros    bigint NOT NULL CHECK (monthly_limit_micros>0),
    max_concurrent_calls    integer NOT NULL CHECK (max_concurrent_calls BETWEEN 1 AND 100000),
    max_call_duration_sec   integer NOT NULL CHECK (max_call_duration_sec BETWEEN 60 AND 86400),
    in_progress_action      varchar(32) NOT NULL CHECK (in_progress_action IN ('STOP_IMMEDIATELY','COMPLETE_CURRENT_TURN')),
    change_summary          varchar(500) NOT NULL CHECK (length(trim(change_summary))>0),
    created_by              uuid NOT NULL,
    retired_at              timestamptz,
    row_version             bigint NOT NULL DEFAULT 1 CHECK (row_version>0),
    created_at              timestamptz NOT NULL DEFAULT now(),
    updated_at              timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT usage_quota_policy_creator_tenant_fk FOREIGN KEY (created_by,tenant_id) REFERENCES user_account(id,tenant_id),
    CONSTRAINT usage_quota_policy_device_tenant_fk FOREIGN KEY (device_id,tenant_id) REFERENCES device(id,tenant_id),
    CONSTRAINT usage_quota_policy_scope_check CHECK (
        (scope_type='TENANT' AND device_id IS NULL) OR (scope_type='DEVICE' AND device_id IS NOT NULL)
    )
);
CREATE UNIQUE INDEX usage_quota_policy_active_tenant ON usage_quota_policy(tenant_id) WHERE status='ACTIVE' AND scope_type='TENANT';
CREATE UNIQUE INDEX usage_quota_policy_active_device ON usage_quota_policy(tenant_id,device_id) WHERE status='ACTIVE' AND scope_type='DEVICE';
CREATE UNIQUE INDEX usage_quota_policy_tenant_version ON usage_quota_policy(tenant_id,version_no) WHERE scope_type='TENANT';
CREATE UNIQUE INDEX usage_quota_policy_device_version ON usage_quota_policy(tenant_id,device_id,version_no) WHERE scope_type='DEVICE';

CREATE TABLE conversation_usage_event (
    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,
    provider_event_id   uuid REFERENCES provider_event(id) ON DELETE SET NULL,
    provider            varchar(40) NOT NULL,
    source_event_key    varchar(255) NOT NULL,
    usage_category      varchar(32) NOT NULL CHECK (usage_category IN ('RTC','END_TO_END_VOICE','ASR','LLM','TTS','STORAGE','POST_PROCESSING')),
    metric_code         varchar(80) NOT NULL CHECK (metric_code ~ '^[a-z][a-z0-9_.-]{1,79}$'),
    quantity            numeric(24,6) NOT NULL CHECK (quantity>=0),
    unit                varchar(40) NOT NULL CHECK (unit ~ '^[a-z][a-z0-9_.-]{1,39}$'),
    occurred_at         timestamptz NOT NULL,
    received_at         timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT conversation_usage_conversation_tenant_fk FOREIGN KEY (conversation_id,tenant_id) REFERENCES conversation(id,tenant_id) ON DELETE CASCADE,
    CONSTRAINT conversation_usage_event_key UNIQUE (tenant_id,provider,source_event_key,usage_category,metric_code,unit)
);
CREATE INDEX conversation_usage_time_idx ON conversation_usage_event(tenant_id,conversation_id,occurred_at,id);

CREATE TABLE conversation_cost_line (
    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,
    usage_event_id      uuid NOT NULL UNIQUE REFERENCES conversation_usage_event(id) ON DELETE CASCADE,
    price_book_id       uuid NOT NULL REFERENCES billing_price_book(id),
    price_rate_id       uuid NOT NULL REFERENCES billing_price_rate(id),
    quantity            numeric(24,6) NOT NULL,
    unit                varchar(40) NOT NULL,
    unit_price_micros   bigint NOT NULL CHECK (unit_price_micros>=0),
    cost_micros         bigint NOT NULL CHECK (cost_micros>=0),
    currency            char(3) NOT NULL CHECK (currency ~ '^[A-Z]{3}$'),
    rated_at            timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT conversation_cost_conversation_tenant_fk FOREIGN KEY (conversation_id,tenant_id) REFERENCES conversation(id,tenant_id) ON DELETE CASCADE
);
CREATE INDEX conversation_cost_tenant_time_idx ON conversation_cost_line(tenant_id,rated_at,conversation_id);

CREATE TABLE conversation_usage_budget (
    conversation_id         uuid PRIMARY KEY REFERENCES conversation(id) ON DELETE CASCADE,
    tenant_id               uuid NOT NULL REFERENCES tenant(id),
    tenant_policy_id        uuid REFERENCES usage_quota_policy(id),
    device_policy_id        uuid REFERENCES usage_quota_policy(id),
    billing_timezone        varchar(64) NOT NULL,
    currency                char(3) NOT NULL CHECK (currency ~ '^[A-Z]{3}$'),
    daily_limit_micros      bigint NOT NULL CHECK (daily_limit_micros>0),
    monthly_limit_micros    bigint NOT NULL CHECK (monthly_limit_micros>0),
    max_call_duration_sec   integer NOT NULL CHECK (max_call_duration_sec BETWEEN 60 AND 86400),
    in_progress_action      varchar(32) NOT NULL CHECK (in_progress_action IN ('STOP_IMMEDIATELY','COMPLETE_CURRENT_TURN')),
    daily_spend_at_create   bigint NOT NULL CHECK (daily_spend_at_create>=0),
    monthly_spend_at_create bigint NOT NULL CHECK (monthly_spend_at_create>=0),
    frozen_at               timestamptz NOT NULL DEFAULT now(),
    CONSTRAINT conversation_usage_budget_tenant_fk FOREIGN KEY (conversation_id,tenant_id) REFERENCES conversation(id,tenant_id) ON DELETE CASCADE
);

COMMIT;