package app

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"os"
	"path/filepath"

	agentcommand "agent-command"
	"agent-system-backend/internal/cmdbus"
	"agent-system-backend/internal/server"
	"agent-system-backend/pkg/extension"
	core "agent-system-core"
)

type compiledRegistry struct {
	skillsRoot string
	bus        *cmdbus.Bus
}

// pluginRegistry 携带插件身份与宿主能力，per-InProc 构造：
// AddCommandHandler 绑定的处理器在分发时按请求 Owner 构造 inprocHost（EXT-1）。
type pluginRegistry struct {
	compiledRegistry
	pluginID string
	caps     hostcaps
	// summary 是本插件的注册面摘要（WP3-I4）：AddAdminZone 声明记录于此，
	// server 经 CompiledPlugins 供给分区清单端点（WP3-I3）。
	summary *server.CompiledPlugin
}

// AddAdminZone 记录管理区分区声明（WP3-I3）：声明即展示元数据，权威记录
// 就是注册期摘要；规格非法（非对象、id/title 缺失）fail-closed 拒绝，
// 使 register() 整体中止（与命令注册同一失败语义）。
func (r pluginRegistry) AddAdminZone(spec json.RawMessage) error {
	if r.summary == nil {
		return errors.New("extension: " + r.pluginID + ": admin zone outside applyCompiled")
	}
	var s extension.AdminZoneSpec
	if err := json.Unmarshal(spec, &s); err != nil {
		return fmt.Errorf("extension: admin zone spec: %w", err)
	}
	if s.ID == "" || s.Title == "" {
		return fmt.Errorf("extension: %s: admin zone requires id and title", r.pluginID)
	}
	r.summary.AdminZones = append(r.summary.AdminZones, server.AdminZoneSection{
		ID: s.ID, Title: s.Title, Icon: s.Icon, Desc: s.Desc, Order: s.Order,
	})
	return nil
}

func (r pluginRegistry) AddCommandHandler(spec json.RawMessage, h extension.Handler) error {
	if r.bus == nil {
		return nil
	}
	if h == nil {
		return fmt.Errorf("extension: %s: nil command handler", r.pluginID)
	}
	var s agentcommand.CommandSpec
	if err := json.Unmarshal(spec, &s); err != nil {
		return fmt.Errorf("extension: command spec: %w", err)
	}
	return r.bus.RegisterPluginCommand(s, func(ctx context.Context, req cmdbus.Request) (any, error) {
		host := inprocHost{caps: r.caps, pluginID: r.pluginID, owner: req.Owner, actor: req.Actor}
		return h(ctx, host, extension.Request{
			ID: req.ID, Params: req.Params, Entrance: req.Entrance,
			Actor: req.Actor, Owner: req.Owner, ConversationID: req.ConversationID,
			HostProjectID: req.HostProjectID,
		})
	})
}

// AddIntent 意图声明（G2-2）：汇入总线意图表；插件身份随声明归因。
func (r pluginRegistry) AddIntent(spec json.RawMessage) error {
	if r.bus == nil {
		return nil
	}
	var is extension.IntentSpec
	if err := json.Unmarshal(spec, &is); err != nil {
		return fmt.Errorf("extension: intent spec: %w", err)
	}
	return r.bus.Intents().Declare(cmdbus.Intent{
		ID: is.ID, Phrases: is.Phrases, Command: is.Command,
		Params: is.Params, Description: is.Description, Plugin: r.pluginID,
	})
}

func (r compiledRegistry) AddSkill(name, markdown string) error {
	if r.skillsRoot == "" || name == "" {
		return nil
	}
	dest := filepath.Join(r.skillsRoot, "compiled", name)
	if err := os.MkdirAll(dest, 0o755); err != nil {
		return err
	}
	return os.WriteFile(filepath.Join(dest, "SKILL.md"), []byte(markdown), 0o644)
}

func (r compiledRegistry) AddCommand(spec json.RawMessage) error {
	if r.bus == nil {
		return nil
	}
	return r.bus.RegisterPluginCommands([]json.RawMessage{spec})
}

// RegisterResourceAuthorizer 声明式扩展无宿主进程内代码，不能提供回调（fail-closed）。
func (r compiledRegistry) RegisterResourceAuthorizer(extension.ResourceAuthorizer) error {
	return errors.New("extension: declarative plugins cannot register resource authorizers")
}

// RegisterResourceAuthorizer 进程内扩展（EXT-1）：填充 EXT-8 适配器槽
// （hostcaps.authz 共享指针；首个注册者生效，组合根已装配进 Server/runmgr）。
// 此前 pluginRegistry 未覆盖该方法——进程内插件注册适配器会命中声明式分支的
// 拒绝，register() 整体中止，插件命令全部未注册（RDM 二进制 rdm.* 全部
// 「unknown command」；MS1 重验收烟测实测发现）。
func (r pluginRegistry) RegisterResourceAuthorizer(fn extension.ResourceAuthorizer) error {
	if fn == nil {
		return errors.New("extension: " + r.pluginID + ": nil resource authorizer")
	}
	r.caps.authz.set(r.pluginID, fn)
	return nil
}

func (r compiledRegistry) Note(kind, name string, payload json.RawMessage) error {
	log.Printf("extension: note %s %s (%d bytes)", kind, name, len(payload))
	return nil
}

// recordRegistry 包装 per-plugin 注册表，把成功注册的声明资产名记入摘要
// （WP3-I4：注册面即清单面——编译插件的管理条目不另设声明口）。
type recordRegistry struct {
	extension.Registry
	sum *server.CompiledPlugin
}

func (r recordRegistry) AddCommand(spec json.RawMessage) error {
	if err := r.Registry.AddCommand(spec); err != nil {
		return err
	}
	if id := specID(spec); id != "" {
		r.sum.Commands = append(r.sum.Commands, id)
	}
	return nil
}

func (r recordRegistry) AddCommandHandler(spec json.RawMessage, h extension.Handler) error {
	if err := r.Registry.AddCommandHandler(spec, h); err != nil {
		return err
	}
	if id := specID(spec); id != "" {
		r.sum.Commands = append(r.sum.Commands, id)
	}
	return nil
}

func (r recordRegistry) AddIntent(spec json.RawMessage) error {
	if err := r.Registry.AddIntent(spec); err != nil {
		return err
	}
	if id := specID(spec); id != "" {
		r.sum.Intents = append(r.sum.Intents, id)
	}
	return nil
}

func (r recordRegistry) AddSkill(name, markdown string) error {
	if err := r.Registry.AddSkill(name, markdown); err != nil {
		return err
	}
	r.sum.Skills = append(r.sum.Skills, name)
	return nil
}

// specID 宽松提取 spec 顶层 id：仅服务清单摘要展示，解析失败返回空串
// 不记录，不影响注册结果本身。
func specID(spec json.RawMessage) string {
	var s struct {
		ID string `json:"id"`
	}
	if err := json.Unmarshal(spec, &s); err != nil {
		return ""
	}
	return s.ID
}

func applyCompiled(skillsRoot string, bus *cmdbus.Bus, caps hostcaps) []server.CompiledPlugin {
	base := compiledRegistry{skillsRoot: skillsRoot, bus: bus}
	var out []server.CompiledPlugin
	for _, e := range extension.Compiled() {
		if e.Register == nil {
			continue
		}
		sum := server.CompiledPlugin{ID: e.ID}
		reg := pluginRegistry{compiledRegistry: base, pluginID: e.ID, caps: caps, summary: &sum}
		// Register 失败的插件保留已成功注册部分（与命令总线一致：部分注册
		// 生效），摘要如实反映实际注册面。
		if err := e.Register(recordRegistry{Registry: reg, sum: &sum}); err != nil {
			log.Printf("extension: %s: %v", e.ID, err)
		}
		out = append(out, sum)
	}
	return out
}

func mergeMCPServers(raw string, extra []core.PluginMCPServer) string {
	var base []json.RawMessage
	if raw != "" {
		if err := json.Unmarshal([]byte(raw), &base); err != nil {
			return raw
		}
	}
	for _, s := range extra {
		b, err := json.Marshal(s)
		if err != nil {
			continue
		}
		base = append(base, b)
	}
	if len(base) == 0 {
		return ""
	}
	out, err := json.Marshal(base)
	if err != nil {
		return raw
	}
	return string(out)
}