package config

import (
	"fmt"
	"os"
	"time"

	"gopkg.in/yaml.v3"
)

// Application 应用配置顶层结构
type Application struct {
	App    AppSection    `yaml:"app"`
	Server ServerSection `yaml:"server"`
	Agent  AgentSection  `yaml:"agent"`
	LLM    LLMSection    `yaml:"llm"`
}

// AppSection 应用基础信息
type AppSection struct {
	Name string `yaml:"name"`
	Env  string `yaml:"env"`
}

// ServerSection 服务器配置
type ServerSection struct {
	Addr string `yaml:"addr"`
}

// AgentSection Agent 配置路径列表
type AgentSection struct {
	ConfigPaths []string `yaml:"config-paths"`
}

// LLMSection LLM 相关配置
type LLMSection struct {
	RequestTimeout string `yaml:"request-timeout"`
}

const defaultLLMRequestTimeout = 5 * time.Minute

// RequestTimeoutDuration 解析 LLM 请求超时时间
func (s LLMSection) RequestTimeoutDuration() (time.Duration, error) {
	if s.RequestTimeout == "" {
		return defaultLLMRequestTimeout, nil
	}
	d, err := time.ParseDuration(s.RequestTimeout)
	if err != nil {
		return 0, fmt.Errorf("invalid llm.request-timeout %q: %w", s.RequestTimeout, err)
	}
	if d <= 0 {
		return 0, fmt.Errorf("llm.request-timeout must be positive, got %q", s.RequestTimeout)
	}
	return d, nil
}

// LoadApplication 从指定路径加载应用配置
func LoadApplication(path string) (Application, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return Application{}, fmt.Errorf("read application config %s: %w", path, err)
	}
	var app Application
	if err := yaml.Unmarshal(data, &app); err != nil {
		return Application{}, fmt.Errorf("parse application config: %w", err)
	}
	// 设置默认值
	if app.Server.Addr == "" {
		app.Server.Addr = ":8091"
	}
	if app.App.Env == "" {
		app.App.Env = "local"
	}
	return app, nil
}