// plexum-fabric-channel-plugin is the Plexum channel plugin that
// connects Plexum agents to a Fabric guild as members.
//
// F-1 (current): identity load, channel config discovery, REST send,
// agentLogin handshake. Plugin advertises channels via manifest +
// reads channels/<name>.json for the Plexum-channel → Fabric-channel
// mapping. The `send` outbound tool posts via Fabric REST.
//
// F-2+ (deferred): socket.io inbound, wakeup gating, token refresh,
// presence sync, sub-discussion, MCP tool surface (~15 tools from
// the openclaw plugin's tools.ts), attachments, channel canvas.
package main

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

	plugin "git.hangman-lab.top/hzhang/Plexum-sdk-go/plugin"

	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/attachments"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/config"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/fabric"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/identity"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/inbound"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/presence"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/subdisc"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/tokens"
	"git.hangman-lab.top/hzhang/Plexum-fabric-channel-plugin/internal/tools"
)

// HostConfig is the plugin's own config at
// <profile>/plugins/plexum-fabric-channel/config.json:
//
//	{
//	  "center_api_base": "http://localhost:7001/api",
//	  "commands_sync_key": "...",   // F-5: enables /command autocomplete in Fabric
//	  "sync_commands": ["new","stop"]  // optional override; defaults to ["new","stop"]
//	}
type HostConfig struct {
	CenterAPIBase           string   `json:"center_api_base"`
	CommandsSyncKey         string   `json:"commands_sync_key,omitempty"`
	SyncCommands            []string `json:"sync_commands,omitempty"`
	PresenceIntervalSeconds int      `json:"presence_interval_seconds,omitempty"` // F-5b; 0 → default 30s
}

type fabricPlugin struct {
	host plugin.HostAPI

	cfgPath    string
	cfg        HostConfig
	identities *identity.Registry
	bindings   []config.FabricBinding
	byFabric   config.ByFabricChannel
	client     *fabric.Client
	tokens     *tokens.Cache
	tools      *tools.Registry

	// Goroutine handle for the inbound supervisor. Cancelled on
	// plugin shutdown (we don't have an explicit shutdown signal in
	// the SDK today; rely on subprocess kill).
	inboundCancel context.CancelFunc
	inboundDone   chan struct{}

	// Legacy field — kept only for back-compat with non-tokens code
	// paths during the F-1 → F-2 refactor; safe to remove once nothing
	// else references it. Not used anymore.
	sessMu   sync.Mutex
	sessions map[string]*fabric.Session
}

func (p *fabricPlugin) Manifest() plugin.Manifest {
	channels := p.dynamicChannelContracts()
	// Tool surface = the agent-facing tool family (port of openclaw
	// plugin's tools.ts, F-4). The "send" outbound is also there for
	// the host's channel manager.
	return plugin.Manifest{
		Name:       config.PluginName,
		Version:    "0.1.0",
		Activation: plugin.ActivationLazy,
		Executable: "plexum-fabric-channel-plugin",
		Contracts: plugin.Contracts{
			Channels: channels,
			Tools:    tools.New(tools.Deps{}).Contracts(),
		},
	}
}

func (p *fabricPlugin) dynamicChannelContracts() []plugin.ChannelContract {
	// Read channels/*.json from <profile>/channels and surface every
	// `plugin: plexum-fabric-channel` entry as a ChannelContract.
	profileRoot := os.Getenv("PLEXUM_PROFILE_ROOT")
	if profileRoot == "" {
		home, _ := os.UserHomeDir()
		profileRoot = filepath.Join(home, ".plexum")
	}
	bindings, err := config.Load(filepath.Join(profileRoot, "channels"))
	if err != nil {
		// Logged later in Init; manifest call can't itself reach a logger.
		return nil
	}
	out := make([]plugin.ChannelContract, 0, len(bindings))
	for _, b := range bindings {
		out = append(out, plugin.ChannelContract{
			Name: b.PlexumChannelName, OutboundTool: "send",
		})
	}
	return out
}

func (p *fabricPlugin) Init(ctx context.Context, host plugin.HostAPI) error {
	p.host = host
	p.sessions = map[string]*fabric.Session{}

	profileRoot := os.Getenv("PLEXUM_PROFILE_ROOT")
	if profileRoot == "" {
		home, _ := os.UserHomeDir()
		profileRoot = filepath.Join(home, ".plexum")
	}

	// Plugin-private config.
	p.cfgPath = filepath.Join(profileRoot, "plugins", config.PluginName, "config.json")
	raw, err := os.ReadFile(p.cfgPath)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		return fmt.Errorf("read %s: %w", p.cfgPath, err)
	}
	if len(raw) > 0 {
		if err := json.Unmarshal(raw, &p.cfg); err != nil {
			return fmt.Errorf("parse %s: %w", p.cfgPath, err)
		}
	}
	if p.cfg.CenterAPIBase == "" {
		p.cfg.CenterAPIBase = "http://localhost:7001/api"
	}
	p.client = fabric.New(p.cfg.CenterAPIBase)

	// Identity.
	idPath := filepath.Join(profileRoot, identity.FileName)
	p.identities, err = identity.Open(idPath)
	if err != nil {
		return fmt.Errorf("identity: %w", err)
	}

	// Channel bindings.
	p.bindings, err = config.Load(filepath.Join(profileRoot, "channels"))
	if err != nil {
		return fmt.Errorf("channel bindings: %w", err)
	}
	p.byFabric = config.Index(p.bindings)

	// Token cache: re-login per agent on TTL miss (8min default).
	p.tokens = tokens.New(0, func(loginCtx context.Context, agentID string) (*fabric.Session, error) {
		entry := p.identities.Lookup(agentID)
		if entry == nil || !entry.Enabled {
			return nil, fmt.Errorf("agent %s: no enabled identity", agentID)
		}
		return p.client.AgentLogin(loginCtx, entry.FabricAPIKey)
	})

	// Sub-discussion KV (F-7); persists across restarts.
	subStore, err := subdisc.Open(subdisc.DefaultPath())
	if err != nil {
		host.Log("warn", "fabric subdisc open", map[string]any{"err": err.Error()})
	}

	// Agent-facing tool surface (port of openclaw's tools.ts).
	p.tools = tools.New(tools.Deps{
		Client: p.client, Tokens: p.tokens, Identities: p.identities,
		SubDisc: subStore,
	})

	host.Log("info", "fabric channel plugin initialized", map[string]any{
		"center":            p.cfg.CenterAPIBase,
		"identity_path":     idPath,
		"channels_loaded":   len(p.bindings),
		"identities_loaded": len(p.identities.AgentIDs()),
	})

	// Warm sessions (early bad-key detection).
	if err := p.warmSessions(ctx); err != nil {
		host.Log("warn", "fabric warm-sessions had errors",
			map[string]any{"err": err.Error()})
	}

	// F-5: push slash command catalog to every guild the bound agents
	// belong to. Cosmetic — gives Fabric frontend "/command" autocomplete.
	// Requires commands_sync_key matching the guild's
	// FABRIC_BACKEND_GUILD_COMMANDS_SYNC_KEY; silently skip when unset.
	if p.cfg.CommandsSyncKey != "" {
		p.syncCommandsToGuilds(ctx)
	}

	// Phase F-2: start the inbound supervisor in a goroutine. Lives
	// until p.inboundCancel fires (currently never — SDK has no
	// shutdown hook; subprocess kill is the only stop signal).
	if len(p.bindings) > 0 {
		ctxBg, cancel := context.WithCancel(context.Background())
		p.inboundCancel = cancel
		p.inboundDone = make(chan struct{})
		notifier := func(channelName, message, sessionID string, media []inbound.MediaItem) {
			payload := map[string]any{
				"channel_name": channelName,
				"message":      message,
				"session_id":   sessionID,
			}
			if len(media) > 0 {
				mediaWire := make([]map[string]any, 0, len(media))
				for _, m := range media {
					mediaWire = append(mediaWire, map[string]any{
						"path":       m.Path,
						"media_type": m.MediaType,
						"name":       m.Name,
					})
				}
				payload["media"] = mediaWire
			}
			p.host.EmitNotification("notifications/plexum/channel/inbound", payload)
		}
		// slog wrapping plugin.HostAPI.Log isn't worth the indirection
		// here; use a discard-style adapter that pipes WARN/INFO to
		// the host log.
		logger := slog.New(&hostLogHandler{host: host, level: slog.LevelInfo})
		sup := inbound.New(p.client, p.tokens, p.bindings, notifier, logger)
		// F-6: enable attachment downloads. Files land under
		// $TMPDIR/plexum-fabric/<msg-id>/<filename>; agents access via
		// the exec tool (cat / file).
		sup.Attachments = attachments.New("")
		go func() {
			defer close(p.inboundDone)
			if err := sup.Run(ctxBg); err != nil {
				host.Log("warn", "inbound supervisor exited", map[string]any{"err": err.Error()})
			}
		}()
		host.Log("info", "fabric inbound supervisor started",
			map[string]any{"agents": sup.AgentIDs, "bindings": len(p.bindings)})

		// F-5b: presence-sync. Shares the inbound supervisor's context
		// so it dies together. Tick interval honours config override.
		interval := time.Duration(p.cfg.PresenceIntervalSeconds) * time.Second
		ps := &presence.Sync{
			Host:       host,
			Client:     p.client,
			Tokens:     p.tokens,
			Identities: p.identities,
			Bindings:   p.bindings,
			Interval:   interval,
		}
		ps.Start(ctxBg)
		host.Log("info", "fabric presence-sync started",
			map[string]any{"interval": ps.Interval.String()})
	}

	return nil
}

// hostLogHandler is a tiny slog.Handler that forwards records to the
// plugin's HostAPI.Log. inbound + supervisor use slog for structured
// logging; this bridges to the host's log notification stream.
type hostLogHandler struct {
	host  plugin.HostAPI
	level slog.Level
}

func (h *hostLogHandler) Enabled(_ context.Context, l slog.Level) bool { return l >= h.level }
func (h *hostLogHandler) Handle(_ context.Context, r slog.Record) error {
	attrs := make(map[string]any, r.NumAttrs())
	r.Attrs(func(a slog.Attr) bool {
		attrs[a.Key] = a.Value.Any()
		return true
	})
	h.host.Log(levelString(r.Level), r.Message, attrs)
	return nil
}
func (h *hostLogHandler) WithAttrs(_ []slog.Attr) slog.Handler { return h }
func (h *hostLogHandler) WithGroup(_ string) slog.Handler      { return h }

func levelString(l slog.Level) string {
	switch {
	case l >= slog.LevelError:
		return "error"
	case l >= slog.LevelWarn:
		return "warn"
	case l >= slog.LevelInfo:
		return "info"
	default:
		return "debug"
	}
}

func (p *fabricPlugin) warmSessions(ctx context.Context) error {
	// Which agents appear as a binding's AgentID?
	agentsNeeded := map[string]bool{}
	for _, b := range p.bindings {
		agentsNeeded[b.AgentID] = true
	}
	enabled := p.identities.EnabledEntries()

	var firstErr error
	for agentID := range agentsNeeded {
		if _, ok := enabled[agentID]; !ok {
			err := fmt.Errorf("agent %s has channels but no identity (run plexum-fabric-register --agent-id %s --api-key ...)",
				agentID, agentID)
			p.host.Log("warn", err.Error(), nil)
			if firstErr == nil {
				firstErr = err
			}
			continue
		}
		sess, err := p.tokens.Get(ctx, agentID)
		if err != nil {
			p.host.Log("warn", "fabric agent warm failed",
				map[string]any{"agent": agentID, "err": err.Error()})
			if firstErr == nil {
				firstErr = err
			}
			continue
		}
		p.host.Log("info", "fabric session warm", map[string]any{
			"agent": agentID, "fabric_user": sess.User.Email,
			"guilds": len(sess.Guilds),
		})
	}
	return firstErr
}

// CallTool dispatches by tool name. "send" is the host-side channel
// outbound (driven by Plexum's channel manager); everything else
// delegates to the tools.Registry built at init time.
func (p *fabricPlugin) CallTool(ctx context.Context, name string, input json.RawMessage) (plugin.ToolResult, error) {
	if name == "send" {
		return p.handleSend(ctx, input)
	}
	if handler := p.tools.Handler(name); handler != nil {
		return handler(ctx, input)
	}
	return plugin.ToolResult{}, fmt.Errorf("unknown tool: %s", name)
}

// handleSend implements the "send" outbound tool: posts the assistant
// reply via Fabric REST as the agent bound to the Plexum channel name.
func (p *fabricPlugin) handleSend(ctx context.Context, input json.RawMessage) (plugin.ToolResult, error) {
	var args struct {
		ChannelName string `json:"channel_name"`
		SessionID   string `json:"session_id"`
		Message     string `json:"message"`
	}
	if err := json.Unmarshal(input, &args); err != nil {
		return plugin.ToolResult{}, fmt.Errorf("parse args: %w", err)
	}
	if args.ChannelName == "" {
		return errResult("channel_name required"), nil
	}
	p.host.Log("info", "fabric send", map[string]any{
		"channel_name": args.ChannelName, "len": len(args.Message),
	})

	var binding *config.FabricBinding
	for i := range p.bindings {
		if p.bindings[i].PlexumChannelName == args.ChannelName {
			binding = &p.bindings[i]
			break
		}
	}
	if binding == nil {
		return errResult("unknown plexum channel: " + args.ChannelName), nil
	}

	sess, err := p.sessionFor(ctx, binding.AgentID)
	if err != nil {
		return errResult("session for agent " + binding.AgentID + ": " + err.Error()), nil
	}

	var endpoint, token string
	for _, g := range sess.Guilds {
		if g.NodeID == binding.FabricGuildNodeID {
			endpoint = g.Endpoint
			break
		}
	}
	for _, t := range sess.GuildAccessTokens {
		if t.GuildNodeID == binding.FabricGuildNodeID {
			token = t.Token
			break
		}
	}
	if endpoint == "" || token == "" {
		return errResult(fmt.Sprintf("agent %s has no access to guild %s",
			binding.AgentID, binding.FabricGuildNodeID)), nil
	}

	if err := p.client.PostMessage(ctx, endpoint, token,
		binding.FabricChannelID, args.Message, sess.User.ID); err != nil {
		return errResult("post: " + err.Error()), nil
	}
	return plugin.NewTextResult("sent"), nil
}

func (p *fabricPlugin) sessionFor(ctx context.Context, agentID string) (*fabric.Session, error) {
	loginCtx, cancel := context.WithTimeout(ctx, 15*time.Second)
	defer cancel()
	return p.tokens.Get(loginCtx, agentID)
}

// syncCommandsToGuilds PUTs the slash-command catalog to every unique
// (agent, guild) the plugin knows about. Best-effort — failure on any
// one guild is logged but doesn't block other guilds.
func (p *fabricPlugin) syncCommandsToGuilds(ctx context.Context) {
	commands := p.cfg.SyncCommands
	if len(commands) == 0 {
		commands = []string{"new", "stop"} // host-side intercepted slashes
	}
	wire := make([]any, 0, len(commands))
	for _, c := range commands {
		wire = append(wire, map[string]any{
			"name": c, "description": "Plexum host-intercepted slash: /" + c,
		})
	}
	seen := map[string]bool{}
	for _, b := range p.bindings {
		sess, err := p.tokens.Get(ctx, b.AgentID)
		if err != nil {
			continue
		}
		for _, g := range sess.Guilds {
			key := b.AgentID + "/" + g.NodeID
			if seen[key] {
				continue
			}
			seen[key] = true
			tok, err := p.tokens.GuildToken(ctx, b.AgentID, g.NodeID)
			if err != nil {
				continue
			}
			if err := p.client.SyncCommands(ctx, g.Endpoint, tok, wire, p.cfg.CommandsSyncKey); err != nil {
				p.host.Log("warn", "fabric commands sync failed",
					map[string]any{"guild": g.NodeID, "err": err.Error()})
			} else {
				p.host.Log("info", "fabric commands synced",
					map[string]any{"guild": g.NodeID, "n": len(commands)})
			}
		}
	}
}

func errResult(msg string) plugin.ToolResult {
	return plugin.ToolResult{
		Content: []plugin.ContentBlock{{Type: "text", Text: msg}},
		IsError: true,
	}
}

func main() {
	if err := plugin.Serve(&fabricPlugin{}); err != nil {
		fmt.Fprintf(os.Stderr, "plexum-fabric-channel-plugin: %v\n", err)
		os.Exit(1)
	}
}