package sysadmin

import "os"

// Feature 功能开关视图。value / effectiveValue 是进程实际读到的配置，
// 不等于能力已经接入；是否可用看 implementationState 与 adapterReadiness。
type Feature struct {
	Key                 string `json:"key"`
	Label               string `json:"label"`
	Group               string `json:"group"`
	Value               string `json:"value"`
	ConfiguredValue     string `json:"configuredValue"`
	EffectiveValue      string `json:"effectiveValue"`
	ImplementationState string `json:"implementationState"`
	AdapterReadiness    string `json:"adapterReadiness"`
	AdapterReason       string `json:"adapterReason,omitempty"`
	RolloutScope        string `json:"rolloutScope"`
	Source              string `json:"source"`
	RequiresRestart     bool   `json:"requiresRestart"`
	Description         string `json:"description"`
}

const (
	implPlaceholder = "placeholder"
	implDryRun      = "dry_run"
	implShadow      = "shadow"
	implLive        = "live"

	adapterReady       = "ready"
	adapterUnavailable = "unavailable"
	adapterDegraded    = "degraded"

	rolloutEnvironment = "environment"
)

type featureMaturity struct {
	state   string
	adapter string
	reason  string
}

// featureMaturityCatalog 是源码接线事实，不随环境变量翻转。
// 未列出的开关视为已接入的环境级能力；列出的项即使配置为 true 也保持此处状态。
var featureMaturityCatalog = map[string]featureMaturity{
	"FAV_PUBLISHER_ENABLED": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "观察窗未授权，禁止 live",
	},
	"FAV_DEGRADED_READ": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "降级读保持关闭",
	},
	"MULTI_INTENT_PLAN_TIER": {
		state: implLive, adapter: adapterDegraded,
		reason: "I2 接线就绪：shadow 持久不可执行计划 + 项目 allowlist + 指标；默认仍 legacy，升档需 allowlist 与阈值验收",
	},
	"INTENT_PLAN_PROJECT_ALLOWLIST": {
		state: implLive, adapter: adapterReady,
		reason: "空值拒绝所有 elevated tier；* 放开全部；逗号分隔项目 ID",
	},
	"MULTI_INTENT_U9_SEGMENT": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "仅有 PI proposer，尚未进入真实聊天分段；提议请求已使用 reasoning profile",
	},
	"MULTI_INTENT_U10_MUTATE": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "适配器仍是 dry-run/validated-only",
	},
	"MULTI_INTENT_U11_DOCGOV": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "适配器仍是 dry-run/validated-only",
	},
	"MULTI_INTENT_U12_RUN_CONTROL": {
		state: implDryRun, adapter: adapterUnavailable,
		reason: "适配器仍是 dry-run/validated-only",
	},
	"SEMANTIC_SUMMARY_SHADOW": {
		state: implShadow, adapter: adapterDegraded,
		reason: "影子组件默认关闭；dev/test schema 61 已含 chat_summaries。摘要请求已用 reasoning profile，pi-agent 经 bind-mount 的 pi-args.mjs 带 --no-tools。授权可见集 digest 仍空",
	},
	"SEMANTIC_SUMMARY_REPLACE": {
		state: implPlaceholder, adapter: adapterUnavailable,
		reason: "替换路径明确未接线，打开开关不会替换叙事",
	},
	"PI_CHANGE_REPORT_NARRATIVE": {
		state: implShadow, adapter: adapterDegraded,
		reason: "只读事实已含截断后的差异片段和影响说明，不含整篇文档。开关默认关闭。叙事请求已用 reasoning profile；pi-agent 经 bind-mount 已带 --no-tools。未授权打开前保持 shadow",
	},
}

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: "INTENT_PLAN_PROJECT_ALLOWLIST", label: "多意图计划项目白名单", group: "intentflow", fallback: "", description: "elevated tier 项目 allowlist：空拒绝；* 全部；逗号分隔项目 ID"},
	{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: "WORKFLOW_SCOPE_MODE", label: "工作流作用域裁决", group: "intent", fallback: "strict", description: "文档命中裁决：strict 命中他流即拦截；weighted 按工作流关系权重打分"},
	{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
			}
		}
		maturity := featureMaturity{state: implLive, adapter: adapterReady}
		if known, ok := featureMaturityCatalog[spec.key]; ok {
			maturity = known
		}
		out = append(out, Feature{
			Key:                 spec.key,
			Label:               spec.label,
			Group:               spec.group,
			Value:               value,
			ConfiguredValue:     value,
			EffectiveValue:      value,
			ImplementationState: maturity.state,
			AdapterReadiness:    maturity.adapter,
			AdapterReason:       maturity.reason,
			RolloutScope:        rolloutEnvironment,
			Source:              "env",
			RequiresRestart:     true,
			Description:         spec.description,
		})
	}
	return out
}