// Package plugins 实现插件宿主（4.6）：manifest + 声明资产 + 可选代码。
// fail-closed：任一资产解析失败整批拒绝该插件并保留上一状态；卸载注销注册项。
// 声明资产热加载：Reload 重扫目录；工具/面板/卡片/意图/工作流/设置全部数据化。
package plugins

import (
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
	"strings"
	"sync"

	"agent-system-backend/internal/settings"
	"agent-system-backend/internal/store"
	"agent-system-backend/internal/tools"
	"agent-system-backend/internal/workflow"
	core "agent-system-core"
)

// Loaded 是一个已装载插件的内存态（注册结果快照）。
type Loaded struct {
	Manifest       core.PluginManifest
	Dir            string
	Panels         []core.PluginPanel
	Cards          map[string][]core.UINode // kind → 模板节点
	Workflows      []core.WorkflowDef
	Scripts        map[string]string      // workflow.ScriptKey → 插件目录内的脚本正文
	Intents        []json.RawMessage      // agent-intent overlay 形态（目录侧消费）
	Commands       []json.RawMessage      // Agent-Command spec overlay（cmdbus 注册）
	Workspaces     []core.PluginWorkspace // 工作区弹层声明（OverlayHost 渲染）
	Prompts        map[string]string      // 文件名 → 内容（画像模板）
	PluginSettings []core.SettingDesc
	Defaults       map[string]any // 插件设置默认值（并入有效设置）
	Skills         map[string]string
	MCP            []core.PluginMCPServer
	Knowledge      []core.PluginKnowledgeSet
	Parsers        []core.PluginParserDecl
	Agents         []core.PluginAgentDecl
	Channels       []core.PluginChannelDecl
	Pages          []core.PluginPageDecl
}

// Host 管理插件目录装载与注册。
type Host struct {
	mu         sync.RWMutex
	st         *store.Store
	registry   *tools.Registry
	settings   *settings.Service
	dir        string
	skillsRoot string
	hostAPI    string
	hostToken  string
	sidecars   map[string]*exec.Cmd
	loaded     map[string]*Loaded // id → loaded
	// OnIntents 在装载集合变化后回调全部意图 overlay（宿主接识别闸门；nil = 不接）。
	OnIntents func(overlay []json.RawMessage) error
	// OnCommands 在装载集合变化后回调全部命令 spec overlay（宿主接命令总线；nil = 不接）。
	OnCommands func(overlay []json.RawMessage) error
	// OnWorkflows 在装载集合变化后回调全部工作流与脚本正文（nil = 不接）。
	OnWorkflows func(defs []core.WorkflowDef, scripts map[string]string) error
}

func New(st *store.Store, reg *tools.Registry, s *settings.Service, dir string) *Host {
	return &Host{st: st, registry: reg, settings: s, dir: dir, loaded: map[string]*Loaded{}, sidecars: map[string]*exec.Cmd{}}
}

type loadAccountGuard struct {
	st                   *store.Store
	actor                string
	allowImplicitDefault bool
	failed               error
}

func (g *loadAccountGuard) check() error {
	if g == nil {
		return nil // startup and existing fixture loader retain legacy behavior
	}
	if g.failed != nil {
		return g.failed
	}
	g.failed = g.st.CheckEffectiveAccountForExternalEffect(g.actor, g.allowImplicitDefault)
	return g.failed
}

func (g *loadAccountGuard) record(err error) error {
	if g != nil && err != nil {
		g.failed = err
	}
	return err
}

// LoadDir 全量装载目录（启动与热加载共用）；返回每个插件的结果（失败不中断其他）。
func (h *Host) LoadDir() map[string]error {
	results, _ := h.loadDir(nil)
	return results
}

// LoadDirAccountChecked reloads on behalf of an already authorized actor.
// Each Backend-owned DB write is fenced in its final transaction; process,
// sidecar and filesystem effects get a fresh state check immediately before
// execution. The caller must separately enforce plugin-management authority.
func (h *Host) LoadDirAccountChecked(actor string, allowImplicitDefault bool) (map[string]error, error) {
	return h.loadDir(&loadAccountGuard{st: h.st, actor: actor, allowImplicitDefault: allowImplicitDefault})
}

func (h *Host) loadDir(guard *loadAccountGuard) (map[string]error, error) {
	if err := guard.check(); err != nil {
		return nil, err
	}
	entries, err := os.ReadDir(h.dir)
	if err != nil {
		if os.IsNotExist(err) {
			return map[string]error{}, nil
		}
		return map[string]error{"<dir>": err}, nil
	}
	results := map[string]error{}
	seen := map[string]bool{}
	for _, e := range entries {
		if !e.IsDir() {
			continue
		}
		id := e.Name()
		seen[id] = true
		results[id] = h.loadOne(filepath.Join(h.dir, id), guard)
		if guard != nil && guard.failed != nil {
			return results, guard.failed
		}
	}
	// 移除已消失的插件（卸载语义）。
	h.mu.Lock()
	for id := range h.loaded {
		if !seen[id] {
			if err := guard.check(); err != nil {
				h.mu.Unlock()
				return results, err
			}
			delete(h.loaded, id)
			if cmd := h.sidecars[id]; cmd != nil && cmd.Process != nil {
				_ = cmd.Process.Kill()
			}
			delete(h.sidecars, id)
			h.registry.UnregisterBySource(core.SourcePlugin, id)
		}
	}
	overlay := h.collectIntentsLocked()
	cmdOverlay := h.collectCommandsLocked()
	defs, scripts := h.collectWorkflowsLocked()
	onIntents, onCommands, onWorkflows := h.OnIntents, h.OnCommands, h.OnWorkflows
	h.mu.Unlock()
	if onCommands != nil {
		if err := guard.check(); err != nil {
			return results, err
		}
		if err := onCommands(cmdOverlay); err != nil {
			results["<commands>"] = err
		}
	}
	if onIntents != nil {
		if err := guard.check(); err != nil {
			return results, err
		}
		if err := onIntents(overlay); err != nil {
			results["<intents>"] = err
		}
	}
	if onWorkflows != nil {
		if err := guard.check(); err != nil {
			return results, err
		}
		if err := onWorkflows(defs, scripts); err != nil {
			results["<workflows>"] = err
		}
	}
	return results, nil
}

// loadOne 装载单个插件；任何失败返回错误且不改变既有注册（fail-closed）。
func (h *Host) loadOne(dir string, guard *loadAccountGuard) error {
	manifestPath := filepath.Join(dir, "plugin.json")
	raw, err := os.ReadFile(manifestPath)
	if err != nil {
		return fmt.Errorf("plugins: %s: %w", filepath.Base(dir), err)
	}
	var m core.PluginManifest
	if err := json.Unmarshal(raw, &m); err != nil {
		return fmt.Errorf("plugins: %s: manifest json: %w", m.ID, err)
	}
	if m.ID == "" || m.Name == "" || m.Version == "" {
		return fmt.Errorf("plugins: %s: manifest missing id/name/version", m.ID)
	}
	if m.APIVersion == "" {
		m.APIVersion = core.PluginAPIVersion
	}
	if !core.PluginAPIAccepted(m.APIVersion) {
		return fmt.Errorf("plugins: %s: apiVersion %s 不在兼容窗口（%s, %s）", m.ID, m.APIVersion, core.PluginAPIVersion, core.PluginAPIVersionExperimental)
	}

	ld := &Loaded{Manifest: m, Dir: dir, Cards: map[string][]core.UINode{}, Prompts: map[string]string{}, Defaults: map[string]any{}, Scripts: map[string]string{}}

	// 同 ID 重载：先注销旧注册（含旧版本工具），再装载新资产。
	if err := guard.check(); err != nil {
		return err
	}
	h.registry.UnregisterBySource(core.SourcePlugin, m.ID)

	// tools/*.json：声明式 HTTP 工具（或含 parameters 的描述型工具）。
	for _, name := range m.Provides.Tools {
		var desc core.ToolDesc
		if err := readAsset(dir, "tools", name, &desc); err != nil {
			return fmt.Errorf("plugins: %s: tool %s: %w", m.ID, name, err)
		}
		desc.Source = core.SourcePlugin
		desc.PluginID = m.ID
		exec, err := h.bindToolExecutor(desc, m.APIVersion, m.Requires.Network)
		if err != nil {
			return fmt.Errorf("plugins: %s: tool %s: %w", m.ID, name, err)
		}
		if err := guard.check(); err != nil {
			return err
		}
		if err := h.registry.Register(desc, exec); err != nil {
			return fmt.Errorf("plugins: %s: register tool %s: %w", m.ID, name, err)
		}
	}

	// panels/*.json
	for _, name := range m.Provides.Panels {
		var panel core.PluginPanel
		if err := readAsset(dir, "panels", name, &panel); err != nil {
			return fmt.Errorf("plugins: %s: panel %s: %w", m.ID, name, err)
		}
		ld.Panels = append(ld.Panels, panel)
	}

	// cards/*.json：{kind, data:[UINode]}
	for _, name := range m.Provides.Cards {
		var card struct {
			Kind string        `json:"kind"`
			Data []core.UINode `json:"data"`
		}
		if err := readAsset(dir, "cards", name, &card); err != nil {
			return fmt.Errorf("plugins: %s: card %s: %w", m.ID, name, err)
		}
		if card.Kind == "" {
			return fmt.Errorf("plugins: %s: card %s: missing kind", m.ID, name)
		}
		ld.Cards[card.Kind] = card.Data
	}

	// workflows/*.json。script 步骤的文件必须留在插件目录内，正文随定义一起交给注册表。
	for _, name := range m.Provides.Workflows {
		var wf core.WorkflowDef
		if err := readAsset(dir, "workflows", name, &wf); err != nil {
			return fmt.Errorf("plugins: %s: workflow %s: %w", m.ID, name, err)
		}
		if err := workflow.Validate(wf, workflow.DeclarativeLimits(), func(tool string) bool {
			_, _, ok := h.registry.Get(tool)
			return ok
		}); err != nil {
			return fmt.Errorf("plugins: %s: workflow %s: %w", m.ID, name, err)
		}
		for _, step := range wf.Steps {
			if step.Kind != "script" {
				continue
			}
			body, err := readPluginFile(dir, step.Script)
			if err != nil {
				return fmt.Errorf("plugins: %s: workflow %s script: %w", m.ID, name, err)
			}
			ld.Scripts[workflow.ScriptKey(wf.ID, step.Script)] = string(body)
		}
		ld.Workflows = append(ld.Workflows, wf)
	}

	// intents/*.json：agent-intent overlay 形态原样透出（目录侧消费，不在此解析）。
	for _, name := range m.Provides.Intents {
		var specs []json.RawMessage
		if err := readAsset(dir, "intents", name, &specs); err != nil {
			return fmt.Errorf("plugins: %s: intents %s: %w", m.ID, name, err)
		}
		ld.Intents = append(ld.Intents, specs...)
	}

	// commands/*.json：Agent-Command spec overlay 形态透出（cmdbuf 注册；不在此校验语义）。
	for _, name := range m.Provides.Commands {
		var specs []json.RawMessage
		if err := readAsset(dir, "commands", name, &specs); err != nil {
			return fmt.Errorf("plugins: %s: commands %s: %w", m.ID, name, err)
		}
		ld.Commands = append(ld.Commands, specs...)
	}

	// workspaces/*.json：工作区弹层声明（T4；OverlayHost 渲染，声明权威在 Core 类型）。
	for _, name := range m.Provides.Workspaces {
		var ws []core.PluginWorkspace
		if err := readAsset(dir, "workspaces", name, &ws); err != nil {
			return fmt.Errorf("plugins: %s: workspaces %s: %w", m.ID, name, err)
		}
		ld.Workspaces = append(ld.Workspaces, ws...)
	}

	// prompts/*.md：画像模板（source=plugin，可被用户复制微调）。
	for _, name := range m.Provides.Prompts {
		content, err := os.ReadFile(filepath.Join(dir, "prompts", name+".md"))
		if err != nil {
			return fmt.Errorf("plugins: %s: prompt %s: %w", m.ID, name, err)
		}
		ld.Prompts[name] = string(content)
	}

	// settings.json：插件设置声明（并入设置中心 schema；默认值进覆盖链底层）。
	if len(m.Provides.Settings) > 0 {
		var descs []core.SettingDesc
		if err := readAsset(dir, "", "settings", &descs); err != nil {
			return fmt.Errorf("plugins: %s: settings: %w", m.ID, err)
		}
		for i := range descs {
			descs[i].Group = "plugin:" + m.ID
			ld.PluginSettings = append(ld.PluginSettings, descs[i])
		}
	}

	if err := h.loadDeclared(dir, m, ld, guard); err != nil {
		return err
	}
	if err := h.startSidecar(m, dir, guard); err != nil {
		return err
	}
	if err := guard.check(); err != nil {
		return err
	}
	h.mu.Lock()
	h.loaded[m.ID] = ld
	overlay := h.collectIntentsLocked()
	cmdOverlay := h.collectCommandsLocked()
	defs, scripts := h.collectWorkflowsLocked()
	onIntents, onCommands, onWorkflows := h.OnIntents, h.OnCommands, h.OnWorkflows
	h.mu.Unlock()
	if guard == nil {
		_ = h.st.UpsertPlugin(m.ID, dir, m)
	} else if err := h.st.UpsertPluginAccountChecked(guard.actor, m.ID, dir, m, guard.allowImplicitDefault); err != nil {
		return guard.record(err)
	}
	if onCommands != nil {
		if err := guard.check(); err != nil {
			return err
		}
		if err := onCommands(cmdOverlay); err != nil {
			return fmt.Errorf("plugins: %s: commands rejected by command bus (kept previous): %w", m.ID, err)
		}
	}
	if onIntents != nil {
		if err := guard.check(); err != nil {
			return err
		}
		if err := onIntents(overlay); err != nil {
			return fmt.Errorf("plugins: %s: intents rejected by host gate (kept previous): %w", m.ID, err)
		}
	}
	if onWorkflows != nil {
		if err := guard.check(); err != nil {
			return err
		}
		if err := onWorkflows(defs, scripts); err != nil {
			return fmt.Errorf("plugins: %s: workflows rejected: %w", m.ID, err)
		}
	}
	return nil
}

// collectIntentsLocked 汇总全部已装载插件的意图 overlay（调用方持锁）。
func (h *Host) collectIntentsLocked() []json.RawMessage {
	var out []json.RawMessage
	for _, ld := range h.loaded {
		out = append(out, ld.Intents...)
	}
	return out
}

// ListWorkspaces 全部已装载插件的工作区声明（GET /api/workspaces 数据源）。
func (h *Host) ListWorkspaces() []core.PluginWorkspace {
	h.mu.RLock()
	defer h.mu.RUnlock()
	var out []core.PluginWorkspace
	for _, ld := range h.loaded {
		out = append(out, ld.Workspaces...)
	}
	return out
}

// collectCommandsLocked 汇总全部已装载插件的命令 overlay（调用方持锁）。
func (h *Host) collectCommandsLocked() []json.RawMessage {
	var out []json.RawMessage
	for _, ld := range h.loaded {
		out = append(out, ld.Commands...)
	}
	return out
}

func (h *Host) collectWorkflowsLocked() ([]core.WorkflowDef, map[string]string) {
	ids := make([]string, 0, len(h.loaded))
	for id := range h.loaded {
		ids = append(ids, id)
	}
	sort.Strings(ids)
	var defs []core.WorkflowDef
	scripts := map[string]string{}
	for _, id := range ids {
		ld := h.loaded[id]
		defs = append(defs, ld.Workflows...)
		for k, v := range ld.Scripts {
			scripts[k] = v
		}
	}
	return defs, scripts
}

func readPluginFile(root, rel string) ([]byte, error) {
	cleaned := filepath.Clean(rel)
	if cleaned == "." || filepath.IsAbs(cleaned) {
		return nil, fmt.Errorf("path %s escapes plugin dir", rel)
	}
	full := filepath.Join(root, cleaned)
	rooted, err := filepath.Rel(root, full)
	if err != nil || rooted == ".." || strings.HasPrefix(rooted, ".."+string(filepath.Separator)) {
		return nil, fmt.Errorf("path %s escapes plugin dir", rel)
	}
	return os.ReadFile(full)
}

func readAsset(dir, sub, name string, v any) error {
	p := filepath.Join(dir, sub, name+".json")
	if sub == "" {
		p = filepath.Join(dir, name+".json")
	}
	raw, err := os.ReadFile(p)
	if err != nil {
		return err
	}
	return json.Unmarshal(raw, v)
}

// ---- 查询接口 ----

func (h *Host) List() []*Loaded {
	h.mu.RLock()
	defer h.mu.RUnlock()
	out := make([]*Loaded, 0, len(h.loaded))
	for _, ld := range h.loaded {
		out = append(out, ld)
	}
	sort.Slice(out, func(i, j int) bool { return out[i].Manifest.ID < out[j].Manifest.ID })
	return out
}

// SettingsSchema 追加插件设置项（settings schema 汇总用）。
func (h *Host) SettingsSchema() []core.SettingDesc {
	h.mu.RLock()
	defer h.mu.RUnlock()
	var out []core.SettingDesc
	for _, ld := range h.List() {
		out = append(out, ld.PluginSettings...)
	}
	return out
}

// Cards 返回 kind → 模板（server 演示卡片注入用）。
func (h *Host) Cards() map[string][]core.UINode {
	h.mu.RLock()
	defer h.mu.RUnlock()
	out := map[string][]core.UINode{}
	for _, ld := range h.loaded {
		for k, v := range ld.Cards {
			out[k] = v
		}
	}
	return out
}

// Unregister 注销插件全部注册项（卸载语义：在途引用由 registry miss 稳定报错）。
func (h *Host) Unregister(id string) {
	h.mu.Lock()
	delete(h.loaded, id)
	cmd := h.sidecars[id]
	delete(h.sidecars, id)
	overlay := h.collectIntentsLocked()
	cmdOverlay := h.collectCommandsLocked()
	defs, scripts := h.collectWorkflowsLocked()
	onIntents, onCommands, onWorkflows := h.OnIntents, h.OnCommands, h.OnWorkflows
	h.mu.Unlock()
	if cmd != nil && cmd.Process != nil {
		_ = cmd.Process.Kill()
	}
	h.registry.UnregisterBySource(core.SourcePlugin, id)
	_ = h.st.RemovePlugin(id)
	if onCommands != nil {
		_ = onCommands(cmdOverlay)
	}
	if onIntents != nil {
		_ = onIntents(overlay)
	}
	if onWorkflows != nil {
		_ = onWorkflows(defs, scripts)
	}
}