-- Migration 019: Enhanced Configuration NOTIFY Triggers
--
-- Implements service-specific PostgreSQL NOTIFY channels for hot-reload
-- Replaces basic notify_config_change() with intelligent routing
--
-- Created: Wave 70 Agent 11
-- Purpose: Enable targeted configuration updates per service

-- ============================================================================
-- Enhanced NOTIFY Trigger Function for config_entries
-- ============================================================================

-- Drop existing trigger if it exists from initial schema
DROP TRIGGER IF EXISTS notify_config_entries_change ON config_entries;

-- Create enhanced function with service-specific channel routing
CREATE OR REPLACE FUNCTION notify_config_change()
RETURNS TRIGGER AS $$
DECLARE
    service_name TEXT;
    category TEXT;
    payload JSON;
    old_val TEXT;
    new_val TEXT;
BEGIN
    -- Extract values for payload
    IF TG_OP = 'DELETE' THEN
        old_val := OLD.value;
        new_val := NULL;
    ELSIF TG_OP = 'UPDATE' THEN
        old_val := OLD.value;
        new_val := NEW.value;
    ELSE -- INSERT
        old_val := NULL;
        new_val := NEW.value;
    END IF;

    -- Extract category from key (e.g., "risk.max_daily_loss" → "risk")
    category := split_part(COALESCE(NEW.key, OLD.key), '.', 1);

    -- Determine service scope based on category
    CASE category
        WHEN 'trading', 'execution', 'order' THEN
            service_name := 'trading';
        WHEN 'risk', 'compliance', 'var', 'circuit' THEN
            service_name := 'trading'; -- Risk is part of trading service
        WHEN 'backtesting', 'strategy', 'simulation', 'backtest' THEN
            service_name := 'backtesting';
        WHEN 'ml', 'training', 'models', 'inference', 'model' THEN
            service_name := 'ml_training';
        WHEN 'api', 'auth', 'gateway', 'jwt', 'mfa', 'rbac' THEN
            service_name := 'api_gateway';
        WHEN 'system', 's3', 'database', 'redis', 'vault' THEN
            service_name := 'global'; -- Infrastructure settings affect all services
        ELSE
            service_name := 'global'; -- Unknown categories go to global channel
    END CASE;

    -- Build notification payload with full context
    payload := json_build_object(
        'operation', TG_OP,
        'table', TG_TABLE_NAME,
        'key', COALESCE(NEW.key, OLD.key),
        'value', new_val,
        'old_value', old_val,
        'category', category,
        'timestamp', EXTRACT(EPOCH FROM NOW()),
        'id', COALESCE(NEW.id, OLD.id)
    );

    -- Send NOTIFY to service-specific channel
    PERFORM pg_notify('config_changed_' || service_name, payload::text);

    -- Also send to global channel for monitoring/debugging
    PERFORM pg_notify('config_changed_global', payload::text);

    RETURN COALESCE(NEW, OLD);
END;
$$ LANGUAGE plpgsql;

-- Apply enhanced trigger to config_entries
CREATE TRIGGER notify_config_entries_change
    AFTER INSERT OR UPDATE OR DELETE ON config_entries
    FOR EACH ROW
    EXECUTE FUNCTION notify_config_change();

COMMENT ON FUNCTION notify_config_change() IS
'Enhanced NOTIFY trigger with service-specific channel routing based on config key prefix.
Channels: config_changed_trading, config_changed_backtesting, config_changed_ml_training,
config_changed_api_gateway, config_changed_global';

-- ============================================================================
-- Enhanced NOTIFY Trigger Function for model_config
-- ============================================================================

CREATE OR REPLACE FUNCTION notify_model_config_change()
RETURNS TRIGGER AS $$
DECLARE
    payload JSON;
    model_name_val TEXT;
    version_val TEXT;
BEGIN
    -- Extract model info for payload
    IF TG_OP = 'DELETE' THEN
        model_name_val := OLD.name;
        version_val := OLD.version;
    ELSE
        model_name_val := NEW.name;
        version_val := NEW.version;
    END IF;

    -- Build notification payload
    payload := json_build_object(
        'operation', TG_OP,
        'table', TG_TABLE_NAME,
        'model_name', model_name_val,
        'version', version_val,
        'is_active', CASE WHEN TG_OP = 'DELETE' THEN false ELSE NEW.is_active END,
        'timestamp', EXTRACT(EPOCH FROM NOW()),
        'id', COALESCE(NEW.id, OLD.id)
    );

    -- Send to ML training service (model owner)
    PERFORM pg_notify('config_changed_ml_training', payload::text);

    -- Also send to trading service (model consumer)
    PERFORM pg_notify('config_changed_trading', payload::text);

    -- Global channel for monitoring
    PERFORM pg_notify('config_changed_global', payload::text);

    RETURN COALESCE(NEW, OLD);
END;
$$ LANGUAGE plpgsql;

-- Drop old trigger and create new one
DROP TRIGGER IF EXISTS notify_model_config_change ON model_config;

CREATE TRIGGER notify_model_config_change
    AFTER INSERT OR UPDATE OR DELETE ON model_config
    FOR EACH ROW
    EXECUTE FUNCTION notify_model_config_change();

COMMENT ON FUNCTION notify_model_config_change() IS
'NOTIFY trigger for model_config changes. Sends to both ml_training (owner) and trading (consumer) services.';

-- ============================================================================
-- Enhanced NOTIFY Trigger Function for Permissions (RBAC)
-- ============================================================================

CREATE OR REPLACE FUNCTION notify_permission_change()
RETURNS TRIGGER AS $$
DECLARE
    payload JSON;
BEGIN
    -- Build notification payload
    payload := json_build_object(
        'operation', TG_OP,
        'table', TG_TABLE_NAME,
        'timestamp', EXTRACT(EPOCH FROM NOW()),
        -- Include IDs based on operation type
        'role_id', CASE
            WHEN TG_TABLE_NAME = 'role_permissions' OR TG_TABLE_NAME = 'user_roles'
            THEN COALESCE(NEW.role_id, OLD.role_id)
            ELSE NULL
        END,
        'permission_id', CASE
            WHEN TG_TABLE_NAME = 'role_permissions'
            THEN COALESCE(NEW.permission_id, OLD.permission_id)
            ELSE NULL
        END,
        'user_id', CASE
            WHEN TG_TABLE_NAME = 'user_roles'
            THEN COALESCE(NEW.user_id, OLD.user_id)
            ELSE NULL
        END
    );

    -- Send to API Gateway (RBAC enforcement point)
    PERFORM pg_notify('permissions_changed', payload::text);

    -- Also send to global for monitoring
    PERFORM pg_notify('config_changed_global', payload::text);

    RETURN COALESCE(NEW, OLD);
END;
$$ LANGUAGE plpgsql;

-- Apply permission change triggers to RBAC tables
-- Note: role_permissions and user_roles triggers already exist from migration 018
-- We're enhancing them here

DROP TRIGGER IF EXISTS trigger_role_permissions_change ON role_permissions;
CREATE TRIGGER trigger_role_permissions_change
    AFTER INSERT OR UPDATE OR DELETE ON role_permissions
    FOR EACH ROW
    EXECUTE FUNCTION notify_permission_change();

DROP TRIGGER IF EXISTS trigger_user_roles_change ON user_roles;
CREATE TRIGGER trigger_user_roles_change
    AFTER INSERT OR UPDATE OR DELETE ON user_roles
    FOR EACH ROW
    EXECUTE FUNCTION notify_permission_change();

DROP TRIGGER IF EXISTS trigger_permissions_change ON permissions;
CREATE TRIGGER trigger_permissions_change
    AFTER INSERT OR UPDATE OR DELETE ON permissions
    FOR EACH ROW
    EXECUTE FUNCTION notify_permission_change();

DROP TRIGGER IF EXISTS trigger_roles_change ON roles;
CREATE TRIGGER trigger_roles_change
    AFTER INSERT OR UPDATE OR DELETE ON roles
    FOR EACH ROW
    EXECUTE FUNCTION notify_permission_change();

COMMENT ON FUNCTION notify_permission_change() IS
'NOTIFY trigger for RBAC permission changes. Sends to permissions_changed channel for API Gateway cache invalidation.';

-- ============================================================================
-- NOTIFY Channels Documentation
-- ============================================================================

COMMENT ON EXTENSION pg_notify IS
'PostgreSQL NOTIFY/LISTEN mechanism for real-time configuration updates.

Active Channels:
- config_changed_trading: Trading service configuration (risk, execution, compliance)
- config_changed_backtesting: Backtesting service configuration (strategy, simulation)
- config_changed_ml_training: ML training service configuration (models, training)
- config_changed_api_gateway: API Gateway configuration (auth, rate limits, routing)
- config_changed_global: All configuration changes (monitoring, debugging)
- permissions_changed: RBAC permission changes (API Gateway cache invalidation)

Payload Format (config_changed_*):
{
  "operation": "INSERT|UPDATE|DELETE",
  "table": "config_entries|model_config",
  "key": "risk.max_daily_loss",
  "value": "100000",
  "old_value": "50000",
  "category": "risk",
  "timestamp": 1730000000.123,
  "id": "uuid"
}

Payload Format (permissions_changed):
{
  "operation": "INSERT|UPDATE|DELETE",
  "table": "role_permissions|user_roles|permissions|roles",
  "timestamp": 1730000000.123,
  "role_id": "uuid",
  "permission_id": "uuid",
  "user_id": "uuid"
}
';

-- ============================================================================
-- Test Queries for NOTIFY Verification
-- ============================================================================

-- Test 1: Risk configuration change (should notify trading service)
-- In psql session 1: LISTEN config_changed_trading;
-- In psql session 2: UPDATE config_entries SET value = '100000' WHERE key = 'risk.max_daily_loss';
-- Expected: Session 1 receives NOTIFY with payload showing old/new values

-- Test 2: ML configuration change (should notify ml_training service)
-- In psql session 1: LISTEN config_changed_ml_training;
-- In psql session 2: UPDATE config_entries SET value = '7200' WHERE key = 'ml.model_cache_ttl';
-- Expected: Session 1 receives NOTIFY

-- Test 3: Global monitoring (receives all changes)
-- In psql session 1: LISTEN config_changed_global;
-- In psql session 2: UPDATE config_entries SET value = '15' WHERE key = 'system.latency_target_ns';
-- Expected: Session 1 receives NOTIFY on global channel

-- Test 4: Model configuration change (should notify both ml_training and trading)
-- In psql session 1: LISTEN config_changed_ml_training;
-- In psql session 2: LISTEN config_changed_trading;
-- In psql session 3: UPDATE model_config SET is_active = true WHERE name = 'mamba2' AND version = 'v1.2.3';
-- Expected: Both sessions 1 and 2 receive NOTIFY

-- Test 5: Permission change (should notify API Gateway)
-- In psql session 1: LISTEN permissions_changed;
-- In psql session 2:
--   INSERT INTO role_permissions (role_id, permission_id)
--   SELECT r.id, p.id FROM roles r, permissions p
--   WHERE r.name = 'trader' AND p.endpoint = 'risk.view_metrics';
-- Expected: Session 1 receives NOTIFY

-- ============================================================================
-- Migration Verification
-- ============================================================================

DO $$
DECLARE
    trigger_count INTEGER;
    function_count INTEGER;
BEGIN
    -- Count triggers on config_entries
    SELECT COUNT(*) INTO trigger_count
    FROM pg_trigger t
    JOIN pg_class c ON t.tgrelid = c.oid
    WHERE c.relname = 'config_entries' AND t.tgname LIKE '%notify%';

    -- Count notify functions
    SELECT COUNT(*) INTO function_count
    FROM pg_proc
    WHERE proname LIKE 'notify_%_change';

    RAISE NOTICE 'Migration 019 Complete:';
    RAISE NOTICE '  - NOTIFY triggers on config_entries: %', trigger_count;
    RAISE NOTICE '  - NOTIFY functions created: %', function_count;
    RAISE NOTICE '  - Service channels: config_changed_{trading,backtesting,ml_training,api_gateway,global}';
    RAISE NOTICE '  - RBAC channel: permissions_changed';
    RAISE NOTICE '';
    RAISE NOTICE 'To test NOTIFY, run in psql:';
    RAISE NOTICE '  Session 1: LISTEN config_changed_trading;';
    RAISE NOTICE '  Session 2: UPDATE config_entries SET value = ''999999'' WHERE key = ''risk.max_daily_loss'';';
END $$;