// plexum-harborforge-plugin — Plexum-side HarborForge plugin.
//
// Mirrors HarborForge.OpenclawPlugin's responsibilities, recast on the
// Plexum SDK:
//
//   - eager activation: plugin spawns at host start so the Monitor
//     bridge listener and Calendar scheduler are running before any
//     turn fires
//   - 9 harborforge_* tools backed by tools.Dispatch
//   - state-aware wake-agent via HostAPI.WakeAgent for Calendar slots
//
// Config layout: <profile>/plugins/harbor-forge/config.json — see
// internal/config/config.go for the schema.
package main

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

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

	"git.hangman-lab.top/zhi/HarborForge.PlexumPlugin/internal/calendar"
	hfcfg "git.hangman-lab.top/zhi/HarborForge.PlexumPlugin/internal/config"
	"git.hangman-lab.top/zhi/HarborForge.PlexumPlugin/internal/monitor"
	"git.hangman-lab.top/zhi/HarborForge.PlexumPlugin/internal/telemetry"
	"git.hangman-lab.top/zhi/HarborForge.PlexumPlugin/internal/tools"
)

// Version is injected via -ldflags "-X main.Version=…" at build time.
var Version = "0.1.0"

// harborForgePlugin satisfies sdkplugin.ToolPlugin.
type harborForgePlugin struct {
	host       sdkplugin.HostAPI
	cfg        hfcfg.Resolved
	bridge     *monitor.Bridge
	sched      *calendar.Scheduler
	deps       tools.Deps
	cancelBg   context.CancelFunc
	wg         sync.WaitGroup
	agentCache sync.Map // sessionID/turnID → agentID stash (best-effort)
}

func (p *harborForgePlugin) Manifest() sdkplugin.Manifest {
	return manifestFromDisk()
}

func (p *harborForgePlugin) Init(ctx context.Context, host sdkplugin.HostAPI) error {
	p.host = host

	profileRoot := os.Getenv("PLEXUM_PROFILE_ROOT")
	if profileRoot == "" {
		home, _ := os.UserHomeDir()
		profileRoot = filepath.Join(home, ".plexum")
	}
	raw, err := hfcfg.Load(profileRoot)
	if err != nil {
		return fmt.Errorf("load harbor-forge config: %w", err)
	}
	p.cfg = hfcfg.Resolve(raw)
	host.Log("info", "harbor-forge plugin initialized", map[string]any{
		"version":           Version,
		"backend":           p.cfg.BackendURL,
		"identifier":        p.cfg.Identifier,
		"monitor_port":      p.cfg.MonitorPort,
		"calendar_enabled":  p.cfg.CalendarEnabled,
	})

	bgCtx, cancel := context.WithCancel(context.Background())
	p.cancelBg = cancel

	// Listers + collectors capture bgCtx (not Init ctx) — Init returns
	// once MCP initialize completes, but the plugin process lives on
	// and so do the goroutines + closures we registered.
	collect := func() telemetry.Snapshot {
		return telemetry.Collect(telemetry.CollectOpts{
			Identifier: p.cfg.Identifier,
			Version:    Version,
			AgentLister: func() []telemetry.AgentInfo {
				return p.listAgents(bgCtx, profileRoot)
			},
		})
	}

	p.bridge = monitor.New(p.cfg.MonitorPort, collect,
		func(level, msg string, attrs map[string]any) { host.Log(level, msg, attrs) })

	if err := p.bridge.Start(bgCtx); err != nil {
		host.Log("warn", "monitor bridge failed to start", map[string]any{"err": err.Error()})
	}

	calBackend := p.cfg.CalendarBackendURL
	if calBackend == "" {
		calBackend = p.cfg.BackendURL
	}
	bridge := calendar.New(calBackend, p.cfg.Identifier)
	p.sched = calendar.NewScheduler(
		calendar.Config{
			HeartbeatInterval: time.Duration(p.cfg.CalendarHeartbeatIntervalSeconds) * time.Second,
		},
		bridge, host,
		calendar.PluginInfoTag{Name: "harbor-forge", Version: Version, Backend: "plexum"},
		func() []calendar.ReportableAgent {
			return p.listReportableAgents(bgCtx, profileRoot)
		},
	)
	if p.cfg.CalendarEnabled {
		p.wg.Add(1)
		go func() {
			defer p.wg.Done()
			if err := p.sched.Run(bgCtx); err != nil {
				host.Log("warn", "calendar scheduler exited", map[string]any{"err": err.Error()})
			}
		}()
	} else {
		host.Log("info", "calendar scheduler disabled by config", nil)
	}

	p.deps = tools.Deps{
		Config:    p.cfg,
		Version:   Version,
		Collect:   collect,
		Bridge:    p.bridge,
		Scheduler: p.sched,
		Host:      host,
		AgentIDFromCtx: func(ctx context.Context) string {
			// Plexum stashes the calling agent id on the host-side
			// context (via WithAgent) before dispatching tool calls.
			// We can't directly import internal/agentloop from a
			// plugin, so we rely on PLEXUM_TOOL_AGENT_ID env-style
			// (set per-call by host when we add that wiring) or fall
			// back to the only-active-agent heuristic. v1: prefer the
			// only-active wake-target (deterministic in single-agent
			// HF deployments).
			return p.bestEffortAgentID()
		},
	}

	return nil
}

func (p *harborForgePlugin) CallTool(ctx context.Context, name string, input json.RawMessage) (sdkplugin.ToolResult, error) {
	return tools.Dispatch(ctx, p.deps, name, input)
}

// ---- agent enumeration ----

// listAgents walks <profile>/agents/*/agent.json + state.json so the
// telemetry payload includes every Plexum agent visible on this host.
// Best-effort: read failures degrade to empty list.
func (p *harborForgePlugin) listAgents(ctx context.Context, profileRoot string) []telemetry.AgentInfo {
	root := filepath.Join(profileRoot, "agents")
	entries, err := os.ReadDir(root)
	if err != nil {
		return nil
	}
	out := make([]telemetry.AgentInfo, 0, len(entries))
	for _, e := range entries {
		if !e.IsDir() {
			continue
		}
		agentID := e.Name()
		var info telemetry.AgentInfo
		info.ID = agentID
		if raw, err := os.ReadFile(filepath.Join(root, agentID, "agent.json")); err == nil {
			var meta struct{ Model string `json:"model"` }
			_ = json.Unmarshal(raw, &meta)
			info.Model = meta.Model
		}
		// State via HostAPI.ReadAgentState — host-side, ground truth.
		if snap, err := p.host.ReadAgentState(ctx, agentID); err == nil {
			info.State = snap.State
		}
		out = append(out, info)
	}
	return out
}

func (p *harborForgePlugin) listReportableAgents(ctx context.Context, profileRoot string) []calendar.ReportableAgent {
	telem := p.listAgents(ctx, profileRoot)
	out := make([]calendar.ReportableAgent, 0, len(telem))
	for _, a := range telem {
		out = append(out, calendar.ReportableAgent{
			ID: a.ID, Model: a.Model,
			State: mapStateToCalendar(a.State),
		})
	}
	return out
}

func mapStateToCalendar(s string) calendar.AgentStatusValue {
	switch strings.ToLower(s) {
	case "idle":
		return calendar.AgentStatusIdle
	case "working":
		return calendar.AgentStatusOnCall
	case "busy":
		return calendar.AgentStatusBusy
	case "offline":
		return calendar.AgentStatusOffline
	}
	return calendar.AgentStatusOffline
}

// bestEffortAgentID is a v1 stop-gap for tools that need the calling
// agent's id but don't have it on the ctx (Plexum SDK doesn't yet
// expose this — TODO upstream). v1: if exactly one agent has an
// active calendar slot we return it; otherwise empty. The calendar
// tools (the only ones that need agent context) usually fire when
// exactly one slot is active.
func (p *harborForgePlugin) bestEffortAgentID() string {
	sch := p.sched.Status()
	if len(sch.Active) != 1 {
		return ""
	}
	// We don't track AgentID on Slot directly — the scheduler keeps
	// activeByAgentID. Iterate to find the one.
	for _, a := range sch.Active {
		// Slot is shared between agents only via the scheduler's maps;
		// here we have just the Slot struct without owner.
		_ = a
	}
	// Fallback to scheduler's helper:
	return p.sched.SingleActiveAgentID()
}

func manifestFromDisk() sdkplugin.Manifest {
	// Bundled manifest.json is the authoritative shape; the binary
	// version reads it next to itself to avoid hand-syncing two
	// definitions. Falls back to a minimal in-code manifest if the
	// file is missing (development / first build).
	exe, err := os.Executable()
	if err == nil {
		raw, err := os.ReadFile(filepath.Join(filepath.Dir(exe), "manifest.json"))
		if err == nil {
			var m sdkplugin.Manifest
			if err := json.Unmarshal(raw, &m); err == nil && m.Name != "" {
				return m
			}
		}
	}
	return sdkplugin.Manifest{
		Name:       "harbor-forge",
		Version:    Version,
		Activation: sdkplugin.ActivationEager,
		Executable: "plexum-harborforge-plugin",
	}
}

func main() {
	p := &harborForgePlugin{}
	defer func() {
		if p.cancelBg != nil {
			p.cancelBg()
		}
		p.wg.Wait()
	}()
	if err := sdkplugin.Serve(p); err != nil && !errors.Is(err, context.Canceled) {
		fmt.Fprintf(os.Stderr, "plexum-harborforge-plugin: %v\n", err)
		os.Exit(1)
	}
}