// Package registry provides the global capability registry. Every capability a
// character can use — tools, skills, channels, MCP servers and IoT providers —
// is registered here so it is globally shared and always available to any
// character and mode (DevDocs/design/01-角色人格与行为模式.md §4).
//
// It is the single source of truth that tool dispatch (M2) and plugin/skill/MCP
// wiring (M5) read from. The registry is safe for concurrent use; it implements
// the pkg/plugins/sdk Registrar interface so plugins register through the SDK
// helpers without knowing this concrete type.
package registry

import (
	"errors"
	"fmt"
	"sync"

	"git.yeij.top/AskaEth/Cyrene_v2/pkg/plugins/sdk"
)

// Kind classifies a registered capability.
type Kind string

const (
	// KindTool is a callable function with a JSON Schema (sdk.Tool).
	KindTool Kind = "tool"
	// KindSkill is a reusable workflow with steps, prompts, refs and guardrails
	// (sdk.Skill).
	KindSkill Kind = "skill"
	// KindChannel is a platform adapter (sdk.Channel).
	KindChannel Kind = "channel"
	// KindMCP is a capability exposed by an MCP server (subsystem-owned).
	KindMCP Kind = "mcp"
	// KindIoT is an IoT device or provider capability (subsystem-owned).
	KindIoT Kind = "iot"
)

// ToolPolicy holds the editable Boolean markers that gate a tool/capability in
// non-owner environments (DevDocs/design/11 §3). Both fields default to false,
// so a capability is owner-only until a marker is explicitly enabled. Policies
// are per-capability and editable at runtime (the admin panel, M10).
type ToolPolicy struct {
	// AllowInGroup permits invocation from a group chat environment.
	AllowInGroup bool
	// AllowInStranger permits invocation from a stranger's private chat
	// environment.
	AllowInStranger bool
}

// Capability is a globally shared, always-available capability registered in
// the registry.
type Capability struct {
	// Name is the unique capability identifier.
	Name string
	// Kind classifies the capability.
	Kind Kind
	// Description is a human-readable summary used for selection and display.
	Description string
	// Policy is the editable reachability markers for this capability. It
	// defaults to zero, which the policy engine reads as owner-only.
	Policy ToolPolicy
	// Origin 是能力的**上游来源章**（DevDocs/audit/MCP工具按上游分组-2026-10-24.md
	// 方案①）：由工具自己通过 sdk.OriginAware 声明，注册汇点
	// RegisterTool/ReplaceTool 盖在这里。零值 = 宿主内置 / 来源未知 ——
	// 这枚章**只用于呈现归属**，不参与权限判定、不进模型可见的工具面
	// （restrict 只按名字查策略，ToolSchemas 只取 Name/Description/Parameters）。
	Origin sdk.Origin
	// Value is the underlying capability object. For KindTool/KindSkill/
	// KindChannel it is the SDK interface from pkg/plugins/sdk; for KindMCP and
	// KindIoT it is owned by the relevant subsystem.
	Value any
}

// Registry is the thread-safe global capability registry.
type Registry struct {
	mu   sync.RWMutex
	caps map[string]Capability
	// store 是策略落盘载体（design/11 §3、裁决 10.4.2）。为 nil 时注册表
	// 退回纯内存态（既有行为）；AttachPolicyStore 装上后，SetPolicy 系列
	// 先落库再改内存。
	store PolicyStore
	// persisted 是最近一次落盘成功的策略快照（能力名 → 标记）。注册表在
	// Register 时用它覆盖能力的初始 Policy，因此「策略在能力注册之前就已落盘」
	// 与「能力先注册、策略后落盘」两种顺序都得到同一个结果。
	persisted map[string]ToolPolicy
}

// Compile-time assertion that *Registry satisfies the SDK Registrar interface.
var _ sdk.Registrar = (*Registry)(nil)

// Sentinel errors returned by the registry. Use errors.Is to test for them.
var (
	// ErrNotFound is returned by Get when no capability has the given name.
	ErrNotFound = errors.New("registry: capability not found")
	// ErrDuplicate is returned by Register when a capability with the same name
	// is already registered.
	ErrDuplicate = errors.New("registry: capability already registered")
	// ErrInvalidArgument is returned when a capability has an empty name, an
	// unknown kind, or a nil Value.
	ErrInvalidArgument = errors.New("registry: invalid capability")
)

// New returns an empty, concurrency-safe registry.
func New() *Registry {
	return &Registry{caps: make(map[string]Capability)}
}

// Register adds cap to the registry. It returns ErrInvalidArgument when the
// name is empty, the kind is unknown or the Value is nil, and ErrDuplicate when
// a capability with the same name already exists.
func (r *Registry) Register(cap Capability) error {
	if cap.Name == "" || !validKind(cap.Kind) || cap.Value == nil {
		return fmt.Errorf("registry: register %q: %w", cap.Name, ErrInvalidArgument)
	}
	r.mu.Lock()
	defer r.mu.Unlock()
	if _, exists := r.caps[cap.Name]; exists {
		return fmt.Errorf("registry: register %q: %w", cap.Name, ErrDuplicate)
	}
	// 落盘策略覆盖注册时带的初始标记：DB 是策略的权威载体（裁决 10.4.2），
	// 因此重启后先 Load、再热注册（MCP 热装等）也能拿到已配置的值。
	if pol, ok := r.persisted[cap.Name]; ok {
		cap.Policy = pol
	}
	r.caps[cap.Name] = cap
	return nil
}

// Get returns the capability registered under name. It returns ErrNotFound when
// no such capability is registered.
func (r *Registry) Get(name string) (Capability, error) {
	r.mu.RLock()
	defer r.mu.RUnlock()
	cap, ok := r.caps[name]
	if !ok {
		return Capability{}, fmt.Errorf("registry: get %q: %w", name, ErrNotFound)
	}
	return cap, nil
}

// Remove deletes the capability registered under name. It returns ErrNotFound
// when no such capability is registered.
func (r *Registry) Remove(name string) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	if _, ok := r.caps[name]; !ok {
		return fmt.Errorf("registry: remove %q: %w", name, ErrNotFound)
	}
	delete(r.caps, name)
	return nil
}

// List returns a copy of the capabilities whose Kind matches kind. An empty
// kind returns every registered capability. The returned slice is owned by the
// caller and safe to mutate.
func (r *Registry) List(kind Kind) []Capability {
	r.mu.RLock()
	defer r.mu.RUnlock()
	out := make([]Capability, 0, len(r.caps))
	for _, cap := range r.caps {
		if kind != "" && cap.Kind != kind {
			continue
		}
		out = append(out, cap)
	}
	return out
}

// Policy returns the editable reachability markers for the capability named
// name. It returns ErrNotFound when no such capability is registered.
func (r *Registry) Policy(name string) (ToolPolicy, error) {
	r.mu.RLock()
	defer r.mu.RUnlock()
	cap, ok := r.caps[name]
	if !ok {
		return ToolPolicy{}, fmt.Errorf("registry: policy %q: %w", name, ErrNotFound)
	}
	return cap.Policy, nil
}

// SetPolicy replaces the reachability markers for the capability named name. It
// returns ErrNotFound when no such capability is registered.
//
// 落盘（裁决 1.3/10.4.2）：已装上 PolicyStore 时先写库，成功后才改内存——
// 写库失败即返回错误、内存保持旧值，绝不产生「面板说保存成功、重启却复位」。
// 顺序是「存在性读 → 落库（锁外做 SQL）→ 持锁套用」。
func (r *Registry) SetPolicy(name string, p ToolPolicy) error {
	if _, err := r.Policy(name); err != nil {
		return fmt.Errorf("registry: set policy %q: %w", name, err)
	}
	if err := r.persist(name, p); err != nil {
		return err
	}
	r.mu.Lock()
	defer r.mu.Unlock()
	cap, ok := r.caps[name]
	if !ok {
		return fmt.Errorf("registry: set policy %q: %w", name, ErrNotFound)
	}
	cap.Policy = p
	r.caps[name] = cap
	r.remember(name, p)
	return nil
}

// SetAllowInGroup toggles the group-chat marker for the capability named name.
// It returns ErrNotFound when no such capability is registered. 它复用
// setPolicyField，因此同样先落库再改内存（裁决 10.4.2）。
func (r *Registry) SetAllowInGroup(name string, allow bool) error {
	return r.setPolicyField(name, "allow_in_group", func(p *ToolPolicy) { p.AllowInGroup = allow })
}

// SetAllowInStranger toggles the stranger-chat marker for the capability named
// name. It returns ErrNotFound when no such capability is registered. 同
// SetAllowInGroup：先落库再改内存。
func (r *Registry) SetAllowInStranger(name string, allow bool) error {
	return r.setPolicyField(name, "allow_in_stranger", func(p *ToolPolicy) { p.AllowInStranger = allow })
}

// setPolicyField 是三个策略写入口共用的「读当前值 → 改一位 → SetPolicy」路径
// （先落库再改内存，见 SetPolicy）。field 只用于错误消息里的操作名。
func (r *Registry) setPolicyField(name, field string, apply func(*ToolPolicy)) error {
	cur, err := r.Policy(name)
	if err != nil {
		return fmt.Errorf("registry: set %s %q: %w", field, name, err)
	}
	apply(&cur)
	if err := r.SetPolicy(name, cur); err != nil {
		return fmt.Errorf("registry: set %s %q: %w", field, name, err)
	}
	return nil
}

// RegisterTool registers t as a KindTool capability.
//
// 它是**来源章的唯一汇点**（DevDocs/audit/MCP工具按上游分组-2026-10-24.md §2 方案①）：
// MCP 工具的**两条接入路径**都从这里进注册表 —— 运行时热装
// （plugin.Manager.start → mcp.NewRegistry → mcp.Registry.Register）与 `.env` 的
// MCP_SERVERS_JSON 启动期装（cmd/cyrene/mcp.go，不经 Manager）—— 因此在这一处盖章
// 一次就覆盖两条路（以及 tools/list_changed 的增量 refresh）。
// 不从 Manager 现场反推归属：那会漏掉 env 路径，把现役接入方式误报成「无来源」。
func (r *Registry) RegisterTool(t sdk.Tool) error {
	if t == nil {
		return fmt.Errorf("registry: register tool: %w", ErrInvalidArgument)
	}
	return r.Register(Capability{
		Name:        t.Name(),
		Kind:        KindTool,
		Description: t.Description(),
		Origin:      originOf(t),
		Value:       t,
	})
}

// originOf 返回 t 自报的来源章；没实现 sdk.OriginAware（宿主内置工具）或自报零值时
// 返回零值 Origin —— 零值在线上表现为**键缺席**，不是一个空对象。
func originOf(t sdk.Tool) sdk.Origin {
	origin, ok := sdk.OriginOf(t)
	if !ok {
		return sdk.Origin{}
	}
	return origin
}

// ReplaceTool 用**同名**的 t 就地换掉已登记的工具条目（热替换，design/09 §5.5：
// 面板保存后下一轮即用新接线，不必重启）。
//
// 与「Remove + Register」的两处实质差别，正是这个窄方法存在的理由：
//   - **原子**：替换在一次写锁内完成，读者中间看不到「这个名字不存在」的空窗
//     （Remove+Register 之间若有 Invoke 落到这个名字上，会得到 ErrUnknownTool）；
//   - **保留 Policy**：分组/陌生人的可达标记是**运行期可改的配置**（§11 §3），
//     不属于工具实现。初始注册时带的标记没有进 persisted 快照，Remove+Register
//     会把它悄悄重置成零值（= 退回 owner-only），用户会看到「面板保存后某个群
//     忽然不能用了」。这里原样沿用内存里的既有标记。
//
// 没有同名条目时返回 ErrNotFound（**不**顺手新增：热替换的语义是「换掉现在这把」，
// 名字打错时静默插入会掩盖调用方的错）；既有条目不是 KindTool 时返回 ErrInvalidArgument。
func (r *Registry) ReplaceTool(t sdk.Tool) error {
	if t == nil || t.Name() == "" {
		return fmt.Errorf("registry: replace tool: %w", ErrInvalidArgument)
	}
	name := t.Name()
	r.mu.Lock()
	defer r.mu.Unlock()
	cur, ok := r.caps[name]
	if !ok {
		return fmt.Errorf("registry: replace %q: %w", name, ErrNotFound)
	}
	if cur.Kind != KindTool {
		return fmt.Errorf("registry: replace %q: 既有能力类型是 %q，不是工具: %w", name, cur.Kind, ErrInvalidArgument)
	}
	r.caps[name] = Capability{
		Name:        name,
		Kind:        KindTool,
		Description: t.Description(),
		// Policy 沿用旧条目的：它是可编辑的运行期配置，不属于工具的构造产出。
		Policy: cur.Policy,
		// Origin **必须重新盖章**：这里逐字段重建条目，漏掉一位就等于「热替换把来源
		// 抹掉」，面板上那把工具会从它的 server 分节里掉进「宿主内置」。来源是工具的
		// 构造产出（跟 RegisterTool 同一口径取），不沿用旧条目 —— 换了实现就该换章。
		Origin: originOf(t),
		Value:  t,
	}
	return nil
}

// RegisterSkill registers s as a KindSkill capability.
func (r *Registry) RegisterSkill(s sdk.Skill) error {
	if s == nil {
		return fmt.Errorf("registry: register skill: %w", ErrInvalidArgument)
	}
	return r.Register(Capability{
		Name:        s.Name(),
		Kind:        KindSkill,
		Description: s.Description(),
		Value:       s,
	})
}

// RegisterChannel registers c as a KindChannel capability.
func (r *Registry) RegisterChannel(c sdk.Channel) error {
	if c == nil {
		return fmt.Errorf("registry: register channel: %w", ErrInvalidArgument)
	}
	return r.Register(Capability{
		Name:        c.Name(),
		Kind:        KindChannel,
		Description: c.Name(),
		Value:       c,
	})
}

// ReplaceChannel 用**同名**的 c 就地更新已登记的渠道条目（热重载，design/04 §3.1）。
//
// 为什么必须是替换而不是 Register：渠道热重载**必然同名**（同名账号的账号名由
// channels.json 决定，重载前后不变），而 Register 遇重名返回 ErrDuplicate，会把
// 新适配器挡在门外 —— 注册表于是继续指向旧实例，管理面板照旧按旧配置读写它的状态
// （显示「未连接」、点「连接」拨的是旧地址）。
//
// 语义是 **upsert**，与 ReplaceTool 有意不同（工具的窄方法是「只换现有这把」）：
//   - 名字不存在 ⇒ 按 RegisterChannel 同口径新增（账号被新加进配置后，热重载是它
//     第一次出现在注册表里的时机，没有别处会替它注册）；
//   - 名字已存在且 Kind == KindChannel ⇒ 覆盖 Value（指向新适配器），**保留既有
//     Policy** —— 分组/陌生人的可达标记是运行期可编辑配置（design/11 §3），不属于
//     适配器的构造产出，热重载把它清掉等于「面板保存一次，某个群忽然不能用了」；
//   - 名字已存在但 Kind != KindChannel ⇒ 报错，绝不悄悄改掉那条能力的类型。
func (r *Registry) ReplaceChannel(c sdk.Channel) error {
	if c == nil || c.Name() == "" {
		return fmt.Errorf("registry: replace channel: %w", ErrInvalidArgument)
	}
	name := c.Name()
	r.mu.Lock()
	defer r.mu.Unlock()
	cur, ok := r.caps[name]
	if !ok {
		// 新增分支与 Register 同口径：落盘策略覆盖初始标记（DB 是策略的权威载体）。
		added := Capability{
			Name:        name,
			Kind:        KindChannel,
			Description: name,
			Value:       c,
		}
		if pol, ok := r.persisted[name]; ok {
			added.Policy = pol
		}
		r.caps[name] = added
		return nil
	}
	if cur.Kind != KindChannel {
		return fmt.Errorf("registry: replace %q: 既有能力类型是 %q，不是渠道: %w", name, cur.Kind, ErrInvalidArgument)
	}
	r.caps[name] = Capability{
		Name: name,
		Kind: KindChannel,
		// Description 与 RegisterChannel 一致地取适配器名（面板按注册名精确匹配）。
		Description: name,
		// Policy 沿用旧条目：它是可编辑的运行期配置，不属于适配器的构造产出。
		Policy: cur.Policy,
		Value:  c,
	}
	return nil
}

// validKind reports whether k is one of the known capability kinds.
func validKind(k Kind) bool {
	switch k {
	case KindTool, KindSkill, KindChannel, KindMCP, KindIoT:
		return true
	default:
		return false
	}
}