package sandbox

import (
	"context"
	"fmt"
	"path/filepath"
	"sync"
	"time"

	"github.com/yaoapp/yao/config"
	"github.com/yaoapp/yao/tai"
	"github.com/yaoapp/yao/tai/registry"
	tairuntime "github.com/yaoapp/yao/tai/runtime"
	taitypes "github.com/yaoapp/yao/tai/types"
	"github.com/yaoapp/yao/workspace"
)

// Manager manages sandbox lifecycle. Node connections are delegated to tai/registry.
type Manager struct {
	boxes  sync.Map
	mu     sync.Mutex
	cancel context.CancelFunc
}

func newManager() *Manager {
	return &Manager{}
}

// Start discovers existing containers from all registered nodes, rebuilds
// the boxes map, and starts the cleanup loop.
// If no "local" node is registered yet, it probes the local Docker environment
// and auto-registers one when available.
func (m *Manager) Start(ctx context.Context) error {
	reg := registry.Global()
	if reg == nil {
		return nil
	}

	m.ensureLocalNode(reg)

	for _, snap := range reg.List() {
		res, err := m.getNode(snap.TaiID)
		if err != nil {
			continue
		}
		m.recoverBoxes(ctx, snap.TaiID, res)
	}

	loopCtx, cancel := context.WithCancel(ctx)
	m.cancel = cancel
	go m.cleanupLoop(loopCtx)
	return nil
}

// ensureLocalNode delegates to tai.RegisterLocal() which probes the local
// Docker environment and registers a "local" node in the registry if available.
// The workspace data directory is derived from config.Conf.DataRoot so that
// workspace files persist across restarts.
func (m *Manager) ensureLocalNode(_ *registry.Registry) {
	dataDir := filepath.Join(config.Conf.DataRoot, "workspaces")
	tai.RegisterLocal(tai.WithDataDir(dataDir))
}

// Nodes returns the list of registered Tai nodes from the registry.
func (m *Manager) Nodes() []taitypes.NodeMeta {
	reg := registry.Global()
	if reg == nil {
		return nil
	}
	return reg.List()
}

// Heartbeat updates the box's last heartbeat timestamp.
func (m *Manager) Heartbeat(sandboxID string, active bool, processCount int) error {
	v, ok := m.boxes.Load(sandboxID)
	if !ok {
		return ErrNotFound
	}
	b := v.(*Box)
	if active {
		b.lastHeartbeat.Store(time.Now().UnixMilli())
	}
	b.processCount.Store(int32(processCount))
	return nil
}

// Host returns a Host handle for executing commands on the Tai host machine.
func (m *Manager) Host(_ context.Context, nodeID string) (*Host, error) {
	if nodeID == "" {
		return nil, ErrNodeMissing
	}

	res, err := m.getNode(nodeID)
	if err != nil {
		return nil, fmt.Errorf("sandbox: connect node %q: %w", nodeID, err)
	}

	if res.HostExec == nil {
		return nil, fmt.Errorf("sandbox: node %q has no host_exec capability", nodeID)
	}

	sys := SystemInfo{
		OS:       res.System.OS,
		Arch:     res.System.Arch,
		Hostname: res.System.Hostname,
		NumCPU:   res.System.NumCPU,
		TotalMem: res.System.TotalMem,
		Shell:    res.System.Shell,
		TempDir:  res.System.TempDir,
	}

	return &Host{nodeID: nodeID, system: sys, manager: m}, nil
}

// Create creates and starts a new sandbox.
func (m *Manager) Create(ctx context.Context, opts CreateOptions) (*Box, error) {
	if opts.Image == "" {
		return nil, fmt.Errorf("sandbox: image is required")
	}

	nodeID := opts.NodeID

	if opts.WorkspaceID != "" {
		if wsm := workspace.M(); wsm != nil {
			node, err := wsm.NodeForWorkspace(ctx, opts.WorkspaceID)
			if err != nil {
				targetNode := nodeID
				if targetNode == "" {
					if nodes := wsm.Nodes(); len(nodes) > 0 {
						for _, n := range nodes {
							if n.Online {
								targetNode = n.Name
								break
							}
						}
					}
				}
				if targetNode == "" {
					return nil, fmt.Errorf("sandbox: resolve workspace %q: no available node", opts.WorkspaceID)
				}
				_, err = wsm.Create(ctx, workspace.CreateOptions{
					ID:    opts.WorkspaceID,
					Name:  opts.WorkspaceID,
					Owner: opts.Owner,
					Node:  targetNode,
				})
				if err != nil {
					return nil, fmt.Errorf("sandbox: auto-create workspace %q: %w", opts.WorkspaceID, err)
				}
				nodeID = targetNode
			} else {
				nodeID = node
			}
		}
	}

	if nodeID == "" {
		return nil, ErrNodeMissing
	}

	id := opts.ID
	if id == "" {
		id = fmt.Sprintf("sb-%d", time.Now().UnixNano())
	}

	res, err := m.getNode(nodeID)
	if err != nil {
		return nil, fmt.Errorf("sandbox: connect node %q: %w", nodeID, err)
	}

	if res.Runtime == nil {
		return nil, fmt.Errorf("sandbox: node %q has no container runtime", nodeID)
	}

	taiOpts := m.buildTaiCreateOptions(opts, nodeID, id)

	containerID, err := res.Runtime.Create(ctx, taiOpts)
	if err != nil {
		return nil, fmt.Errorf("sandbox: create container: %w", err)
	}

	if err := res.Runtime.Start(ctx, containerID); err != nil {
		res.Runtime.Remove(ctx, containerID, true)
		return nil, fmt.Errorf("sandbox: start container: %w", err)
	}

	policy := opts.Policy
	if policy == "" {
		policy = Session
	}

	sys := SystemInfo{
		OS:       res.System.OS,
		Arch:     res.System.Arch,
		Hostname: res.System.Hostname,
		NumCPU:   res.System.NumCPU,
		TotalMem: res.System.TotalMem,
		Shell:    res.System.Shell,
		TempDir:  res.System.TempDir,
	}

	boxWorkDir := opts.WorkDir
	if boxWorkDir == "" {
		boxWorkDir = "/workspace"
	}

	box := &Box{
		id:           id,
		containerID:  containerID,
		nodeID:       nodeID,
		owner:        opts.Owner,
		policy:       policy,
		labels:       opts.Labels,
		idleTimeoutD: opts.IdleTimeout,
		maxLifetimeD: opts.MaxLifetime,
		stopTimeoutD: opts.StopTimeout,
		createdAt:    time.Now(),
		manager:      m,
		vnc:          opts.VNC,
		image:        opts.Image,
		workspaceID:  opts.WorkspaceID,
		workDir:      boxWorkDir,
		system:       sys,
	}
	box.lastCall.Store(time.Now().UnixMilli())

	m.boxes.Store(id, box)
	return box, nil
}

// Get returns an existing sandbox by ID.
func (m *Manager) Get(_ context.Context, id string) (*Box, error) {
	v, ok := m.boxes.Load(id)
	if !ok {
		return nil, ErrNotFound
	}
	return v.(*Box), nil
}

// GetOrCreate returns existing sandbox by ID or creates a new one.
func (m *Manager) GetOrCreate(ctx context.Context, opts CreateOptions) (*Box, error) {
	if opts.ID != "" {
		if v, ok := m.boxes.Load(opts.ID); ok {
			return v.(*Box), nil
		}
	}
	return m.Create(ctx, opts)
}

// List returns all sandboxes, optionally filtered.
func (m *Manager) List(_ context.Context, opts ListOptions) ([]*Box, error) {
	var result []*Box
	m.boxes.Range(func(_, value any) bool {
		b := value.(*Box)
		if opts.Owner != "" && b.owner != opts.Owner {
			return true
		}
		if opts.NodeID != "" && b.nodeID != opts.NodeID {
			return true
		}
		if len(opts.Labels) > 0 {
			for k, v := range opts.Labels {
				if b.labels[k] != v {
					return true
				}
			}
		}
		result = append(result, b)
		return true
	})
	return result, nil
}

// Remove force-removes a sandbox (SIGKILL + delete).
func (m *Manager) Remove(ctx context.Context, id string) error {
	v, ok := m.boxes.Load(id)
	if !ok {
		return ErrNotFound
	}
	b := v.(*Box)

	res, err := m.getNode(b.nodeID)
	if err == nil && res.Runtime != nil {
		res.Runtime.Remove(ctx, b.containerID, true)
	}

	m.boxes.Delete(id)
	return nil
}

// Cleanup removes idle/expired sandboxes.
func (m *Manager) Cleanup(ctx context.Context) error {
	now := time.Now()
	m.boxes.Range(func(key, value any) bool {
		b := value.(*Box)
		idle := now.Sub(b.lastActiveTime())

		switch b.policy {
		case OneShot:
			// handled after Exec
		case Session:
			if timeout := b.idleTimeout(); timeout > 0 && idle > timeout {
				m.Remove(ctx, b.id)
			}
		case LongRunning:
			if timeout := b.idleTimeout(); timeout > 0 && idle > timeout {
				if res, err := m.getNode(b.nodeID); err == nil && res.Runtime != nil {
					res.Runtime.Stop(ctx, b.containerID, b.stopTimeout())
				}
			}
			if lifetime := b.maxLifetime(); lifetime > 0 && now.Sub(b.createdAt) > lifetime {
				m.Remove(ctx, b.id)
			}
		case Persistent:
			// never auto-cleaned
		}
		return true
	})
	return nil
}

// Close stops the cleanup loop. Node connections are managed by the registry.
func (m *Manager) Close() error {
	if m.cancel != nil {
		m.cancel()
	}
	return nil
}

func (m *Manager) cleanupLoop(ctx context.Context) {
	ticker := time.NewTicker(1 * time.Minute)
	defer ticker.Stop()
	for {
		select {
		case <-ticker.C:
			m.Cleanup(ctx)
		case <-ctx.Done():
			return
		}
	}
}

func (m *Manager) getNode(name string) (*tai.ConnResources, error) {
	res, ok := tai.GetResources(name)
	if !ok {
		return nil, ErrNodeNotFound
	}
	return res, nil
}

func (m *Manager) buildTaiCreateOptions(opts CreateOptions, nodeID, sandboxID string) tairuntime.CreateOptions {
	env := make(map[string]string)

	reg := registry.Global()
	if reg != nil {
		if snap, ok := reg.Get(nodeID); ok {
			grpcEnv := BuildGRPCEnv(snap.Mode, snap.Addr, sandboxID)
			for k, v := range grpcEnv {
				env[k] = v
			}
		}
	}

	for k, v := range opts.Env {
		env[k] = v
	}

	labels := map[string]string{
		"managed-by":      "yao-sandbox",
		"sandbox-id":      sandboxID,
		"sandbox-owner":   opts.Owner,
		"sandbox-node-id": nodeID,
		"sandbox-policy":  string(opts.Policy),
	}
	if opts.VNC {
		labels["sandbox-vnc"] = "true"
	}
	if opts.WorkspaceID != "" {
		labels["workspace-id"] = opts.WorkspaceID
	}
	for k, v := range opts.Labels {
		labels[k] = v
	}

	workDir := opts.WorkDir
	if workDir == "" {
		workDir = "/workspace"
	}

	cmd := []string{"sh", "-c", "trap 'exit 0' TERM; while :; do sleep 86400 & wait $!; done"}

	var ports []tairuntime.PortMapping
	for _, p := range opts.Ports {
		ports = append(ports, tairuntime.PortMapping{
			ContainerPort: p.ContainerPort,
			HostPort:      p.HostPort,
			HostIP:        p.HostIP,
			Protocol:      p.Protocol,
		})
	}

	var binds []string
	if opts.WorkspaceID != "" {
		if wsm := workspace.M(); wsm != nil {
			mountPath := opts.MountPath
			if mountPath == "" {
				mountPath = "/workspace"
			}
			mode := opts.MountMode
			if mode == "" {
				mode = "rw"
			}
			hostPath, _ := wsm.MountPath(context.Background(), opts.WorkspaceID)
			if hostPath != "" {
				binds = append(binds, fmt.Sprintf("%s:%s:%s", hostPath, mountPath, mode))
			}
		}
	}

	return tairuntime.CreateOptions{
		Name:       sandboxID,
		Image:      opts.Image,
		Cmd:        cmd,
		Env:        env,
		Binds:      binds,
		WorkingDir: workDir,
		User:       opts.User,
		Memory:     opts.Memory,
		CPUs:       opts.CPUs,
		VNC:        opts.VNC,
		Ports:      ports,
		Labels:     labels,
	}
}

func (m *Manager) recoverBoxes(ctx context.Context, nodeID string, res *tai.ConnResources) {
	if res.Runtime == nil {
		return
	}
	containers, err := res.Runtime.List(ctx, tairuntime.ListOptions{
		All:    true,
		Labels: map[string]string{"managed-by": "yao-sandbox"},
	})
	if err != nil {
		return
	}

	for _, c := range containers {
		sandboxID := c.Labels["sandbox-id"]
		if sandboxID == "" {
			continue
		}
		if _, loaded := m.boxes.Load(sandboxID); loaded {
			continue
		}

		cid := c.ID
		if c.Name != "" {
			cid = c.Name
		}
		hasVNC := c.Labels["sandbox-vnc"] == "true"
		if !hasVNC {
			for _, p := range c.Ports {
				if p.ContainerPort == 5900 || p.ContainerPort == 6080 {
					hasVNC = true
					break
				}
			}
		}
		box := &Box{
			id:          sandboxID,
			containerID: cid,
			nodeID:      c.Labels["sandbox-node-id"],
			owner:       c.Labels["sandbox-owner"],
			policy:      LifecyclePolicy(c.Labels["sandbox-policy"]),
			labels:      c.Labels,
			createdAt:   time.Now(),
			image:       c.Image,
			workspaceID: c.Labels["workspace-id"],
			vnc:         hasVNC,
			workDir:     "/workspace",
			manager:     m,
		}
		box.lastCall.Store(time.Now().UnixMilli())
		m.boxes.Store(sandboxID, box)
	}
}

// ImageExists reports whether the given image ref exists on the target node.
func (m *Manager) ImageExists(ctx context.Context, nodeID, ref string) (bool, error) {
	res, err := m.getNode(nodeID)
	if err != nil {
		return false, err
	}
	if res.Image == nil {
		return true, nil
	}
	return res.Image.Exists(ctx, ref)
}

// PullImage pulls an image to the target node, returning a channel of
// real-time progress events.
func (m *Manager) PullImage(ctx context.Context, nodeID, ref string, opts ImagePullOptions) (<-chan tairuntime.PullProgress, error) {
	res, err := m.getNode(nodeID)
	if err != nil {
		return nil, err
	}
	if res.Image == nil {
		return nil, nil
	}
	pullOpts := tairuntime.PullOptions{}
	if opts.Auth != nil {
		pullOpts.Auth = &tairuntime.RegistryAuth{
			Username: opts.Auth.Username,
			Password: opts.Auth.Password,
			Server:   opts.Auth.Server,
		}
	}
	return res.Image.Pull(ctx, ref, pullOpts)
}

// EnsureImage checks whether the image exists on the node; if not, it
// pulls the image and blocks until the pull completes.
func (m *Manager) EnsureImage(ctx context.Context, nodeID, ref string, opts ImagePullOptions) error {
	exists, err := m.ImageExists(ctx, nodeID, ref)
	if err != nil {
		return fmt.Errorf("image exists check: %w", err)
	}
	if exists {
		return nil
	}

	ch, err := m.PullImage(ctx, nodeID, ref, opts)
	if err != nil {
		return fmt.Errorf("image pull: %w", err)
	}
	if ch == nil {
		return nil
	}

	for p := range ch {
		if p.Error != "" {
			return fmt.Errorf("image pull %q: %s", ref, p.Error)
		}
	}
	return nil
}