package main

// ops.go — the lvmh-ops control container: an agent pi with docker access
// (docker.sock bind) that prepares repos, builds per-repo worker images and
// registers them via /api/repos. Kept alive by StartOpsLoop.

import (
	"context"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"time"

	cerrdefs "github.com/containerd/errdefs"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/volume"
)

// Ops container wiring constants.
const (
	opsImageRef              string        = "lvmh-ops:latest"
	opsContainerName         string        = "lvmh-ops"
	labelOps                 string        = "lvmh.ops"
	opsSessionID             string        = "lvmh-ops-control"
	envControlDockerfile     string        = "LVMH_CONTROL_DOCKERFILE"
	defaultControlDockerfile string        = "/app/build/docker/control.Dockerfile"
	opsRecheckInterval       time.Duration = 30 * time.Second

	volumeOpsWork string = "lvmh-ops-work"
	opsMount      string = "/ops"
	opsAPIBase    string = "http://lvmh:8686"
	dockerSock    string = "/var/run/docker.sock"
)

// EnsureOps guarantees the ops control container is running: a running
// container is a no-op, a stopped one is started, a missing one is built
// (image) + created + started. Errors are returned, never fatal — the ops
// loop logs them and retries on the next tick (docker may be down at boot).
func (s *Spawner) EnsureOps(ctx context.Context) error {
	inspect, err := s.cli.ContainerInspect(ctx, opsContainerName)
	if err == nil {
		if inspect.State != nil && inspect.State.Running {
			return nil
		}
		return s.cli.ContainerStart(ctx, opsContainerName, container.StartOptions{})
	}
	if !cerrdefs.IsNotFound(err) {
		return fmt.Errorf("inspect %s: %w", opsContainerName, err)
	}
	if err := s.ensureOpsImage(ctx); err != nil {
		return err
	}
	return s.createOps(ctx)
}

// ensureOpsImage builds the ops image when missing, from the control
// Dockerfile (build context derived like the worker's: dir above the
// dockerfile's dir).
func (s *Spawner) ensureOpsImage(ctx context.Context) error {
	exists, err := s.imageRefExists(ctx, opsImageRef)
	if err != nil {
		return err
	}
	if exists {
		return nil
	}
	if _, err := os.Stat(s.controlDockerfile); err != nil {
		return fmt.Errorf("control Dockerfile missing at %s: %w", s.controlDockerfile, err)
	}
	return s.buildImage(ctx, filepath.Dir(filepath.Dir(s.controlDockerfile)), s.controlDockerfile, opsImageRef)
}

// createOps creates and starts the ops container with its own workspace
// volume, the shared session/pi caches, and the docker socket. Never
// auto-removed: the loop restarts it in place.
func (s *Spawner) createOps(ctx context.Context) error {
	for _, vol := range []string{volumeOpsWork, volumeSessions, volumePiCache} {
		if _, err := s.cli.VolumeCreate(ctx, volume.CreateOptions{Name: vol}); err != nil {
			return fmt.Errorf("volume %s: %w", vol, err)
		}
	}
	env := []string{
		envProviderAPIKey + "=" + os.Getenv(envProviderAPIKey),
		envToken + "=" + daemonToken,
		"LVMH_URL=" + s.containerURL,
		envLVMHSessionID + "=" + opsSessionID,
		envLVMHAgent + "=1",
		"LVMH_API=" + opsAPIBase,
	}
	if pat, ok, _ := s.store.GetSetting(settingGitLabToken); ok && pat != "" {
		env = append(env, "LVMH_GITEA_TOKEN="+pat)
	}
	cfg := &container.Config{
		Image:      opsImageRef,
		Env:        env,
		WorkingDir: opsMount,
		Labels:     map[string]string{labelOps: "true", labelSession: opsSessionID},
	}
	hostCfg := &container.HostConfig{
		Binds: []string{
			volumeOpsWork + ":" + opsMount,
			volumeSessions + ":" + sessionsMount,
			volumePiCache + ":" + cacheMount,
			dockerSock + ":" + dockerSock,
		},
		NetworkMode: container.NetworkMode(s.network),
		AutoRemove:  false,
		Init:        &[]bool{true}[0],
	}
	if _, err := s.cli.ContainerCreate(ctx, cfg, hostCfg, nil, nil, opsContainerName); err != nil {
		return fmt.Errorf("docker create: %w", err)
	}
	if err := s.cli.ContainerStart(ctx, opsContainerName, container.StartOptions{}); err != nil {
		s.removeContainer(context.Background(), opsContainerName)
		return fmt.Errorf("docker start: %w", err)
	}
	return nil
}

// StartOpsLoop keeps the ops container alive, re-checking every
// opsRecheckInterval. Ensure failures are logged, never fatal.
func (s *Spawner) StartOpsLoop(ctx context.Context) {
	go func() {
		if err := s.EnsureOps(ctx); err != nil {
			log.Printf("ops: ensure: %v", err)
		}
		ticker := time.NewTicker(opsRecheckInterval)
		defer ticker.Stop()
		for {
			select {
			case <-ctx.Done():
				return
			case <-ticker.C:
				if err := s.EnsureOps(ctx); err != nil {
					log.Printf("ops: ensure: %v", err)
				}
			}
		}
	}()
}

// RemoveOps stops and removes the ops container by NAME (it has no
// containers-table row, so RemoveSession cannot handle it). The ops loop
// recreates it on the next tick.
func (s *Spawner) RemoveOps(_ context.Context) error {
	stopCtx, cancel := context.WithTimeout(context.Background(), time.Duration(stopTimeoutSeconds)*time.Second)
	if err := s.cli.ContainerStop(stopCtx, opsContainerName, container.StopOptions{}); err != nil && !cerrdefs.IsNotFound(err) {
		cancel()
		return fmt.Errorf("docker stop: %w", err)
	}
	cancel()
	s.removeContainer(context.Background(), opsContainerName)
	return nil
}