package main

import (
	"context"
	"encoding/json"
	"errors"
	"strings"

	"git.soma.salesforce.com/chatbots/realtime-media-conductor/rmc"
)

// MessageStatsAgent is trusted, embedded Go code. It receives filtered room
// input but is not sandboxed from the host's filesystem or network.
type MessageStatsAgent struct{}

func (MessageStatsAgent) Descriptor() rmc.RoomAgentDescriptor {
	return rmc.RoomAgentDescriptor{
		ID: "example.message-stats", Version: "1", Role: "processor",
		Subscriptions: []rmc.ChannelSubscription{{
			ChannelID: "chat", EventTypes: []string{"text.message.committed"},
		}},
		Grants: []rmc.Grant{
			{Action: "event:subscribe", Resource: "chat"},
			{Action: "event:publish", Resource: "measurements"},
		},
		TimeoutMillis: 1000,
	}
}

func (MessageStatsAgent) Handle(ctx context.Context, request rmc.RoomAgentRequest) ([]rmc.EventInput, error) {
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	var message struct {
		Text string `json:"text"`
	}
	if err := json.Unmarshal(request.Event.Payload, &message); err != nil {
		return nil, err
	}
	if strings.TrimSpace(message.Text) == "" {
		return nil, errors.New("message text is required")
	}
	payload, err := json.Marshal(struct {
		SourceEventID string `json:"source_event_id"`
		WordCount     int    `json:"word_count"`
	}{request.Event.ID, len(strings.Fields(message.Text))})
	if err != nil {
		return nil, err
	}
	return []rmc.EventInput{{
		ChannelID: "measurements", Type: "demo.message.measured",
		CausationID: request.Event.ID, Visibility: request.Event.Visibility,
		Payload: payload,
	}}, nil
}