package agent

import "git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"

// defaultPurpose labels CallRecords when Options.Purpose is empty.
const defaultPurpose = "agent"

// buildRequest assembles a model.Request for one step: the agent's instructions
// prepended as a leading system message, plus the conversation messages, the
// configured model/temperature/max-tokens/purpose and the registered tool
// schemas. When a router is injected it overrides the model from the request
// contents, which is how vision requests are routed to the vision model.
//
// 本路径与流式主路径（loop.buildRequest）共用同一处 persona 钩子（裁决 03.4.1）：
// 角色由**适配器视图**携带（model.PersonaScoped，见 model/persona_stack.go），
// 写成请求上的 PersonaID，模型路由也按它走。为什么角色不在本函数参数里：RunStep
// 由 loop 与 automations 调用，角色只存在于 loop 的会话环境 ctx 里，而 agent
// 不能反向 import loop；按角色分开注入的适配器视图（一角色一 agent，
// design/22 §4.2 方案 A）是唯一不依赖 ctx 的载体。
//
// 角色**已知**时才切到 RouteRequestForPersona：未知角色（普通 *model.Router 或
// 未绑角色的视图）保持原来的 RouteRequest —— 后者带 vision 模型的改写规则，
// RouteRequestForPersona 刻意不含（图像路由已归 vision.Router，裁决 14.4.1/14.4.5）。
func (a *Agent) buildRequest(messages []model.Message) model.Request {
	req := model.Request{
		Model:       a.opts.Model,
		Messages:    a.assembleMessages(messages),
		Temperature: a.temperature(),
		MaxTokens:   a.opts.MaxTokens,
		Purpose:     a.purpose(),
		Tools:       a.toolSchemas(),
	}
	if ps, ok := a.adapter.(model.PersonaScoped); ok {
		req.PersonaID = ps.ScopedPersona()
	}
	if a.router != nil {
		if pr, ok := a.router.(model.PersonaRouter); ok && req.PersonaID != "" {
			if routeModel, _ := pr.RouteRequestForPersona(req.PersonaID, req); routeModel != "" {
				req.Model = routeModel
			}
			return req
		}
		if routeModel, _ := a.router.RouteRequest(req); routeModel != "" {
			req.Model = routeModel
		}
	}
	return req
}

// assembleMessages returns messages with the agent's instructions prepended as a
// leading system message when instructions are non-empty, otherwise the input
// slice is returned unchanged.
func (a *Agent) assembleMessages(messages []model.Message) []model.Message {
	if a.instructions == "" {
		return messages
	}
	out := make([]model.Message, 0, len(messages)+1)
	out = append(out, model.TextMessage(model.RoleSystem, a.instructions))
	out = append(out, messages...)
	return out
}

// temperature returns the temperature pointer to place in a Request. Zero maps
// to nil so the provider default applies.
func (a *Agent) temperature() *float64 {
	if a.opts.Temperature == 0 {
		return nil
	}
	t := a.opts.Temperature
	return &t
}

// purpose returns the CallRecord purpose label, defaulting to defaultPurpose.
func (a *Agent) purpose() string {
	if a.opts.Purpose == "" {
		return defaultPurpose
	}
	return a.opts.Purpose
}

// toolSchemas returns the registered tool schemas advertised to the model, or
// nil when no dispatcher is configured.
func (a *Agent) toolSchemas() []model.ToolSpec {
	if a.tools == nil {
		return nil
	}
	return a.tools.ToolSchemas()
}