package engine

// backend.go - EngineBackend 接口定义.
//
// 升华改进(ELEVATED): 原设计在主循环中散落 Provider==nil 判断
// (创建 api.Client / 构建 api.MessageRequest / 调用 CreateMessageStream).
// 现在通过 EngineBackend 接口将两个路径封装:
//   - anthropicBackend:直连 Anthropic API(走 api.Client)
//   - providerBackend:通过 flyto.ModelProvider 接口
//
// 主循环只调 backend.BuildAndStream(),不再感知双路径差异.

import (
	"context"

	agentctx "git.flytoex.net/yuanwei/flyto-agent/pkg/context"
	"git.flytoex.net/yuanwei/flyto-agent/pkg/flyto"
	"git.flytoex.net/yuanwei/flyto-agent/pkg/query"
)

// EngineBackend 封装"构建请求 + 流式调用"两个操作.
//
// 主循环只调此接口,不判断 Provider==nil.
type EngineBackend interface {
	// BuildAndStream 构建请求并发起流式调用.
	// attempt 用于可观测性(记录在重试日志中).
	BuildAndStream(ctx context.Context, model string, maxTokens int, promptBlocks []agentctx.SystemPromptBlock, messages []query.Message, toolDefs any, responseFormat *flyto.ResponseFormat, attempt int) (<-chan flyto.Event, error)
}