package sysadmin

import "os"

// Feature 功能开关视图；value 统一用字符串表示。
type Feature struct {
	Key             string `json:"key"`
	Label           string `json:"label"`
	Group           string `json:"group"`
	Value           string `json:"value"`
	Source          string `json:"source"`
	RequiresRestart bool   `json:"requiresRestart"`
	Description     string `json:"description"`
}

type featureSpec struct {
	key         string // 环境变量名
	label       string
	group       string
	fallback    string // 组合根未提供生效值时的兜底
	description string
}

// featureCatalog 覆盖 config.Config 主要开关与各业务包灰度 flag（宁全勿缺）。
// 生效值由组合根（app）解析后注入，避免本包反向依赖业务模块。
var featureCatalog = []featureSpec{
	{key: "AGENT_BACKEND", label: "Agent 执行后端", group: "agent", fallback: "pi-agent", description: "对话与任务执行的 Agent 后端（stub / cursor / pi-agent）"},
	{key: "MAX_CONCURRENT_AGENTS", label: "Agent 全局并发上限", group: "agent", fallback: "8", description: "保护 pi-agent / GPU / API 的并发闸"},
	{key: "PI_AGENT_RUNNER_URL", label: "PI Runner 地址", group: "agent", fallback: "", description: "产品内 PI Agent Runner 服务地址；空表示未接入"},
	{key: "ALLOW_IN_MEMORY", label: "允许内存降级模式", group: "system", fallback: "false", description: "数据库不可用时降级内存模式（仅限本地 Demo）"},
	{key: "AUTH_REGISTRATION_ENABLED", label: "开放注册", group: "auth", fallback: "true", description: "是否允许用户自主注册"},
	{key: "AUTH_REQUIRE_APPROVAL", label: "注册需审核", group: "auth", fallback: "false", description: "新注册用户是否需要管理员审核后激活"},
	{key: "FAV_PUBLISHER_ENABLED", label: "FAV 发布器", group: "artifact-vault", fallback: "false", description: "Final Artifact Vault 后台发布器；默认关闭"},
	{key: "FAV_DEGRADED_READ", label: "FAV 降级读", group: "artifact-vault", fallback: "false", description: "FAV 缺失时允许降级读取；默认关闭"},
	{key: "INTENT_V2_SHADOW", label: "意图 V2 影子模式", group: "intent", fallback: "false", description: "V2 意图识别影子运行，仅观测不接管"},
	{key: "INTENT_V2_DECISION", label: "意图 V2 决策", group: "intent", fallback: "false", description: "V2 意图识别接管路由决策"},
	{key: "INTENT_V2_DECISION_TIER", label: "意图 V2 决策档位", group: "intent", fallback: "none", description: "V2 灰度风险档位：none/query/generate/write_low/write_high/all"},
	{key: "WORKFLOW_INTENTS_ENABLED", label: "工作流意图", group: "intent", fallback: "true", description: "识别工作流类意图"},
	{key: "MULTI_INTENT_ENABLED", label: "多意图识别", group: "intent", fallback: "true", description: "单条消息多意图拆解"},
	{key: "MULTI_INTENT_PLAN_TIER", label: "多意图计划档位", group: "intentflow", fallback: "legacy", description: "意图计划灰度：legacy/shadow/auto_read/confirm/full"},
	{key: "MULTI_INTENT_U9_SEGMENT", label: "U9 LLM 分段", group: "intentflow", fallback: "false", description: "LLM 意图分段提议"},
	{key: "MULTI_INTENT_U10_MUTATE", label: "U10 变更适配器", group: "intentflow", fallback: "false", description: "低/中风险 mutate 动作适配器"},
	{key: "MULTI_INTENT_U11_DOCGOV", label: "U11 文档治理适配器", group: "intentflow", fallback: "false", description: "docgov 动作适配器"},
	{key: "MULTI_INTENT_U12_RUN_CONTROL", label: "U12 运行控制适配器", group: "intentflow", fallback: "false", description: "workflow/run-control 动作适配器"},
	{key: "SEMANTIC_SUMMARY_SHADOW", label: "语义摘要影子", group: "ctxmgr", fallback: "false", description: "上下文语义摘要影子生成"},
	{key: "SEMANTIC_SUMMARY_REPLACE", label: "语义摘要替换", group: "ctxmgr", fallback: "false", description: "语义摘要替换确定性叙事（保留位，未接线）"},
	{key: "PI_CHANGE_REPORT_NARRATIVE", label: "PI 变更报告叙事", group: "docrevision", fallback: "false", description: "变更报告 PI 叙事增强；默认仅确定性回退"},
}

// Features 返回功能开关快照；source 恒为 env，均需重启生效。
func (s *Service) Features() []Feature {
	values := map[string]string{}
	if s.featureValues != nil {
		values = s.featureValues()
	}
	out := make([]Feature, 0, len(featureCatalog))
	for _, spec := range featureCatalog {
		value, ok := values[spec.key]
		if !ok {
			if env, set := os.LookupEnv(spec.key); set {
				value = env
			} else {
				value = spec.fallback
			}
		}
		out = append(out, Feature{
			Key:             spec.key,
			Label:           spec.label,
			Group:           spec.group,
			Value:           value,
			Source:          "env",
			RequiresRestart: true,
			Description:     spec.description,
		})
	}
	return out
}