package plugins

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

	"github.com/jfraeys/fetch_ml/internal/container"
	"github.com/jfraeys/fetch_ml/internal/logging"
	trackingpkg "github.com/jfraeys/fetch_ml/internal/tracking"
)

// TensorBoardOptions configure the TensorBoard plugin.
type TensorBoardOptions struct {
	PortAllocator *trackingpkg.PortAllocator
	Image         string
	LogBasePath   string
}

type tensorboardSidecar struct {
	containerID string
	port        int
}

// TensorBoardPlugin exposes training logs through TensorBoard.
type TensorBoardPlugin struct {
	logger   *logging.Logger
	podman   *container.PodmanManager
	sidecars map[string]*tensorboardSidecar
	opts     TensorBoardOptions
	mu       sync.Mutex
}

// NewTensorBoardPlugin constructs a TensorBoard plugin instance.
func NewTensorBoardPlugin(
	logger *logging.Logger,
	podman *container.PodmanManager,
	opts TensorBoardOptions,
) (*TensorBoardPlugin, error) {
	if podman == nil {
		return nil, fmt.Errorf("podman manager is required for TensorBoard plugin")
	}
	if opts.Image == "" {
		opts.Image = "tensorflow/tensorflow:2.17.0"
	}
	if opts.LogBasePath == "" {
		return nil, fmt.Errorf("log base path is required for TensorBoard plugin")
	}
	if opts.PortAllocator == nil {
		opts.PortAllocator = trackingpkg.NewPortAllocator(5700, 5900)
	}

	return &TensorBoardPlugin{
		logger:   logger,
		podman:   podman,
		opts:     opts,
		sidecars: make(map[string]*tensorboardSidecar),
	}, nil
}

// Name returns the plugin name.
func (t *TensorBoardPlugin) Name() string {
	return "tensorboard"
}

// ProvisionSidecar starts TensorBoard to tail a task's log directory.
func (t *TensorBoardPlugin) ProvisionSidecar(
	ctx context.Context,
	taskID string,
	config trackingpkg.ToolConfig,
) (map[string]string, error) {
	if config.Mode == trackingpkg.ModeRemote || config.Mode == trackingpkg.ModeDisabled {
		return nil, nil
	}

	jobName := trackingpkg.StringSetting(config.Settings, "job_name")
	if jobName == "" {
		jobName = taskID
	}

	logDir := filepath.Join(t.opts.LogBasePath, jobName)
	if err := os.MkdirAll(logDir, 0750); err != nil {
		return nil, fmt.Errorf("failed to ensure tensorboard log dir: %w", err)
	}

	port, err := t.opts.PortAllocator.Allocate()
	if err != nil {
		return nil, err
	}

	containerName := fmt.Sprintf("tensorboard-%s", taskID)
	cmd := []string{
		"tensorboard",
		"--logdir", "/logs",
		"--host", "0.0.0.0",
		"--port", "6006",
	}

	cfg := &container.ContainerConfig{
		Name:    containerName,
		Image:   t.opts.Image,
		Command: cmd,
		Volumes: map[string]string{
			logDir: "/logs:ro",
		},
		Ports: map[int]int{
			port: 6006,
		},
		Network: container.NetworkConfig{
			AllowNetwork: true,
		},
	}

	containerID, err := t.podman.StartContainer(ctx, cfg)
	if err != nil {
		t.opts.PortAllocator.Release(port)
		return nil, err
	}

	t.mu.Lock()
	t.sidecars[taskID] = &tensorboardSidecar{
		containerID: containerID,
		port:        port,
	}
	t.mu.Unlock()

	return map[string]string{
		"TENSORBOARD_URL":          fmt.Sprintf("http://127.0.0.1:%d", port),
		"TENSORBOARD_HOST_LOG_DIR": logDir,
	}, nil
}

// Teardown stops the TensorBoard sidecar.
func (t *TensorBoardPlugin) Teardown(ctx context.Context, taskID string) error {
	t.mu.Lock()
	sidecar, ok := t.sidecars[taskID]
	if ok {
		delete(t.sidecars, taskID)
	}
	t.mu.Unlock()

	if !ok {
		return nil
	}

	if sidecar.port != 0 {
		t.opts.PortAllocator.Release(sidecar.port)
	}

	if sidecar.containerID == "" {
		return nil
	}

	if err := t.podman.StopContainer(ctx, sidecar.containerID); err != nil && t.logger != nil {
		t.logger.Warn("failed to stop tensorboard container", "task_id", taskID, "error", err)
	}
	if err := t.podman.RemoveContainer(ctx, sidecar.containerID); err != nil && t.logger != nil {
		t.logger.Warn("failed to remove tensorboard container", "task_id", taskID, "error", err)
	}

	return nil
}

// HealthCheck currently returns true; extend with HTTP checks later.
func (t *TensorBoardPlugin) HealthCheck(context.Context, trackingpkg.ToolConfig) bool {
	return true
}