package service

import (
	"context"
	"fmt"
	"strings"

	"ai-agent-scaffold-go/internal/model"
)

// RunnerImpl Runner 的默认实现
type RunnerImpl struct {
	appName string
	agent   model.Agent
}

// NewRunner 创建 Runner
func NewRunner(appName string, agent model.Agent) *RunnerImpl {
	return &RunnerImpl{
		appName: appName,
		agent:   agent,
	}
}

// CreateSession 创建会话 ID
func (r *RunnerImpl) CreateSession(userID string) (string, error) {
	if strings.TrimSpace(userID) == "" {
		return "", fmt.Errorf("user id is required")
	}
	next := sessionCounter.Add(1)
	return fmt.Sprintf("%s:%s:%d", r.appName, userID, next), nil
}

// Run 同步执行
func (r *RunnerImpl) Run(userID, sessionID string, content model.ChatContent) ([]string, error) {
	if strings.TrimSpace(userID) == "" || strings.TrimSpace(sessionID) == "" {
		return nil, fmt.Errorf("user id and session id are required")
	}
	output, err := r.agent.Run(context.Background(), content)
	if err != nil {
		return nil, err
	}
	if output == "" {
		return []string{}, nil
	}
	return []string{output}, nil
}

// Stream 流式执行
func (r *RunnerImpl) Stream(userID, sessionID string, content model.ChatContent) (<-chan string, <-chan error) {
	outputs := make(chan string, 8)
	errs := make(chan error, 1)

	go func() {
		defer close(outputs)
		defer close(errs)

		if strings.TrimSpace(userID) == "" || strings.TrimSpace(sessionID) == "" {
			errs <- fmt.Errorf("user id and session id are required")
			return
		}
		if err := r.agent.Stream(context.Background(), content, outputs); err != nil {
			errs <- err
		}
	}()

	return outputs, errs
}