package docker

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"sort"
	"strings"
	"time"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/events"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/api/types/network"
	"github.com/docker/docker/api/types/registry"
	"github.com/docker/docker/api/types/system"
	"github.com/docker/docker/api/types/volume"
	"github.com/docker/docker/client"
	"github.com/docker/docker/pkg/stdcopy"
)

// Client wraps the Docker client with additional functionality
type Client struct {
	cli       *client.Client
	probeHost string
}

// NewClient creates a new Docker client
func NewClient() (*Client, error) {
	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		return nil, fmt.Errorf("failed to create Docker client: %w", err)
	}

	// Test connection
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	_, err = cli.Ping(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to Docker daemon: %w", err)
	}

	return &Client{cli: cli}, nil
}

// HostProbeHost returns an address through which host-published container
// ports are reachable. When this process runs inside a container, host
// loopback is unreachable; the bridge gateway IP routes to ports published
// on 0.0.0.0. Result is cached for the process lifetime.
func (c *Client) HostProbeHost(ctx context.Context) string {
	if c.probeHost != "" {
		return c.probeHost
	}
	host := "127.0.0.1"
	if self, err := c.self(ctx); err == nil && self.NetworkSettings != nil {
		for _, n := range self.NetworkSettings.Networks {
			if n != nil && n.Gateway != "" {
				host = n.Gateway
				break
			}
		}
	}
	c.probeHost = host
	return host
}

// OwnNetworkName returns the name of the platform network this process's
// container is attached to, or "" when not running containerized. Per-project
// and default Docker networks are never selected; among remaining networks
// the lexicographically first wins so the choice is deterministic.
func (c *Client) OwnNetworkName(ctx context.Context) string {
	self, err := c.self(ctx)
	if err != nil || self.NetworkSettings == nil {
		return ""
	}
	names := make([]string, 0, len(self.NetworkSettings.Networks))
	for name := range self.NetworkSettings.Networks {
		switch {
		case name == "bridge" || name == "host" || name == "none":
		case strings.HasPrefix(name, "containr-proj-"):
		default:
			names = append(names, name)
		}
	}
	sort.Strings(names)
	if len(names) == 0 {
		return ""
	}
	return names[0]
}

// self inspects the container this process runs in (hostname == container ID).
func (c *Client) self(ctx context.Context) (types.ContainerJSON, error) {
	hostname, err := os.Hostname()
	if err != nil || hostname == "" {
		return types.ContainerJSON{}, fmt.Errorf("hostname unavailable")
	}
	return c.cli.ContainerInspect(ctx, hostname)
}

// ConnectSelfToNetwork attaches this process's container to the given network.
// No-op when already attached or when not running containerized.
func (c *Client) ConnectSelfToNetwork(ctx context.Context, networkName string) error {
	hostname, err := os.Hostname()
	if err != nil || hostname == "" {
		return fmt.Errorf("hostname unavailable")
	}
	err = c.cli.NetworkConnect(ctx, networkName, hostname, &network.EndpointSettings{})
	if err != nil && strings.Contains(strings.ToLower(err.Error()), "already exists") {
		return nil
	}
	return err
}

// ListContainers returns all containers
func (c *Client) ListContainers(ctx context.Context, all bool) ([]types.Container, error) {
	return c.cli.ContainerList(ctx, container.ListOptions{
		All: all,
	})
}

// ListContainersFiltered returns containers matching the given filters.
func (c *Client) ListContainersFiltered(ctx context.Context, f filters.Args, all bool) ([]types.Container, error) {
	return c.cli.ContainerList(ctx, container.ListOptions{
		All:     all,
		Filters: f,
	})
}

// GetContainer returns detailed information about a specific container
func (c *Client) GetContainer(ctx context.Context, containerID string) (types.ContainerJSON, error) {
	return c.cli.ContainerInspect(ctx, containerID)
}

// CreateContainer creates a new container
func (c *Client) CreateContainer(ctx context.Context, config ContainerConfig) (string, error) {
	containerConfig := &container.Config{
		Image:        config.Image,
		Cmd:          config.Cmd,
		Env:          config.Env,
		Labels:       config.Labels,
		ExposedPorts: config.ExposedPorts,
		Healthcheck:  config.Healthcheck,
	}

	hostConfig := &container.HostConfig{
		RestartPolicy: container.RestartPolicy{
			Name: container.RestartPolicyMode(config.RestartPolicy),
		},
		PortBindings: config.PortBindings,
		Mounts:       config.Mounts,
		Resources: container.Resources{
			Memory:            config.Memory,
			MemoryReservation: config.MemoryReservation,
			NanoCPUs:          config.NanoCPUs,
			CPUShares:         config.CPUShares,
		},
		NetworkMode: container.NetworkMode(config.NetworkMode),
	}

	networkingConfig := &network.NetworkingConfig{
		EndpointsConfig: config.Networks,
	}

	resp, err := c.cli.ContainerCreate(
		ctx,
		containerConfig,
		hostConfig,
		networkingConfig,
		nil,
		config.Name,
	)

	if err != nil {
		return "", fmt.Errorf("failed to create container: %w", err)
	}

	return resp.ID, nil
}

// StartContainer starts a container
func (c *Client) StartContainer(ctx context.Context, containerID string) error {
	return c.cli.ContainerStart(ctx, containerID, container.StartOptions{})
}

// StopContainer stops a container
func (c *Client) StopContainer(ctx context.Context, containerID string, timeout *time.Duration) error {
	var timeoutInt *int
	if timeout != nil {
		t := int(timeout.Seconds())
		timeoutInt = &t
	}
	return c.cli.ContainerStop(ctx, containerID, container.StopOptions{
		Timeout: timeoutInt,
	})
}

// RestartContainer restarts a container
func (c *Client) RestartContainer(ctx context.Context, containerID string, timeout *time.Duration) error {
	var timeoutInt *int
	if timeout != nil {
		t := int(timeout.Seconds())
		timeoutInt = &t
	}
	return c.cli.ContainerRestart(ctx, containerID, container.StopOptions{
		Timeout: timeoutInt,
	})
}

// RemoveContainer removes a container
func (c *Client) RemoveContainer(ctx context.Context, containerID string, force bool) error {
	return c.cli.ContainerRemove(ctx, containerID, container.RemoveOptions{
		Force: force,
	})
}

// GetContainerLogs returns logs for a container
func (c *Client) GetContainerLogs(ctx context.Context, containerID string, options LogOptions) (io.ReadCloser, error) {
	return c.cli.ContainerLogs(ctx, containerID, container.LogsOptions{
		ShowStdout: options.Stdout,
		ShowStderr: options.Stderr,
		Follow:     options.Follow,
		Tail:       options.Tail,
		Timestamps: options.Timestamps,
	})
}

// CopyFromContainer streams a tar archive of srcPath out of a container.
// The container only needs to exist — it does not have to be running.
func (c *Client) CopyFromContainer(ctx context.Context, containerID, srcPath string) (io.ReadCloser, error) {
	reader, _, err := c.cli.CopyFromContainer(ctx, containerID, srcPath)
	return reader, err
}

// CopyToContainer copies a tar archive stream into a container path.
func (c *Client) CopyToContainer(ctx context.Context, containerID, dstPath string, content io.Reader) error {
	return c.cli.CopyToContainer(ctx, containerID, dstPath, content, container.CopyToContainerOptions{})
}

// GetContainerStats returns real-time resource usage statistics for a container
func (c *Client) GetContainerStats(ctx context.Context, containerID string, stream bool) (*container.StatsResponseReader, error) {
	resp, err := c.cli.ContainerStats(ctx, containerID, stream)
	if err != nil {
		return nil, err
	}
	return &resp, nil
}

// ListImages returns all images
func (c *Client) ListImages(ctx context.Context, all bool) ([]image.Summary, error) {
	return c.cli.ImageList(ctx, image.ListOptions{
		All: all,
	})
}

// PullImage pulls an image from a registry. The pull runs as the returned
// stream is consumed — callers must drain and close it (or use
// PullImageWait) or the pull may be aborted.
func (c *Client) PullImage(ctx context.Context, ref string, auth registry.AuthConfig) (io.ReadCloser, error) {
	authStr, _ := registry.EncodeAuthConfig(auth)
	return c.cli.ImagePull(ctx, ref, image.PullOptions{
		RegistryAuth: authStr,
	})
}

// PullImageWait pulls an image and blocks until the pull stream completes.
func (c *Client) PullImageWait(ctx context.Context, ref string, auth registry.AuthConfig) error {
	reader, err := c.PullImage(ctx, ref, auth)
	if err != nil {
		return err
	}
	defer reader.Close()
	// The daemon performs the pull while streaming progress; drain it fully
	// and surface any errorDetail the daemon reports in the stream.
	dec := json.NewDecoder(reader)
	var msg struct {
		ErrorDetail *struct {
			Message string `json:"message"`
		} `json:"errorDetail"`
		Error string `json:"error"`
	}
	for dec.Decode(&msg) == nil {
		if msg.ErrorDetail != nil {
			return fmt.Errorf("%s", msg.ErrorDetail.Message)
		}
		if msg.Error != "" {
			return fmt.Errorf("%s", msg.Error)
		}
	}
	return nil
}

// BuildImage builds an image from a Dockerfile
func (c *Client) BuildImage(ctx context.Context, buildContext io.Reader, options BuildOptions) (types.ImageBuildResponse, error) {
	resp, err := c.cli.ImageBuild(ctx, buildContext, types.ImageBuildOptions{
		Dockerfile: options.Dockerfile,
		Tags:       options.Tags,
		BuildArgs:  options.BuildArgs,
		Labels:     options.Labels,
		Remove:     options.Remove,
		NoCache:    options.NoCache,
	})
	if err != nil {
		return resp, err
	}
	// The daemon aborts the build if the response stream isn't consumed,
	// and reports failures only inside that stream.
	defer resp.Body.Close()
	var buildErr string
	dec := json.NewDecoder(resp.Body)
	for {
		var line struct {
			ErrorDetail struct {
				Message string `json:"message"`
			} `json:"errorDetail"`
			Error string `json:"error"`
		}
		if err := dec.Decode(&line); err != nil {
			break
		}
		if line.ErrorDetail.Message != "" {
			buildErr = line.ErrorDetail.Message
		} else if line.Error != "" {
			buildErr = line.Error
		}
	}
	if buildErr != "" {
		return resp, fmt.Errorf("docker build failed: %s", buildErr)
	}
	return resp, nil
}

// RemoveImage removes an image
func (c *Client) RemoveImage(ctx context.Context, imageID string, force bool) ([]image.DeleteResponse, error) {
	return c.cli.ImageRemove(ctx, imageID, image.RemoveOptions{
		Force: force,
	})
}

// TagImage tags an image
func (c *Client) TagImage(ctx context.Context, imageID, ref string) error {
	return c.cli.ImageTag(ctx, imageID, ref)
}

// ListNetworks returns all networks
func (c *Client) ListNetworks(ctx context.Context) ([]network.Summary, error) {
	return c.cli.NetworkList(ctx, network.ListOptions{})
}

// CreateNetwork creates a new network
func (c *Client) CreateNetwork(ctx context.Context, config NetworkConfig) (string, error) {
	resp, err := c.cli.NetworkCreate(ctx, config.Name, network.CreateOptions{
		Driver:   config.Driver,
		Internal: config.Internal,
		Labels:   config.Labels,
	})
	if err != nil {
		return "", err
	}
	return resp.ID, nil
}

// RemoveNetwork removes a network
func (c *Client) RemoveNetwork(ctx context.Context, networkID string) error {
	return c.cli.NetworkRemove(ctx, networkID)
}

// NetworkGateway returns the IPAM gateway of a network — the address
// containers on it can use to reach host-published ports.
func (c *Client) NetworkGateway(ctx context.Context, networkID string) string {
	resp, err := c.cli.NetworkInspect(ctx, networkID, network.InspectOptions{})
	if err != nil {
		return ""
	}
	for _, cfg := range resp.IPAM.Config {
		if cfg.Gateway != "" {
			return cfg.Gateway
		}
	}
	return ""
}

// ConnectNetwork connects a container to a network
func (c *Client) ConnectNetwork(ctx context.Context, networkID, containerID string, config network.EndpointSettings) error {
	return c.cli.NetworkConnect(ctx, networkID, containerID, &config)
}

// DisconnectNetwork disconnects a container from a network
func (c *Client) DisconnectNetwork(ctx context.Context, networkID, containerID string, force bool) error {
	return c.cli.NetworkDisconnect(ctx, networkID, containerID, force)
}

// ListVolumes returns all volumes
func (c *Client) ListVolumes(ctx context.Context) (volume.ListResponse, error) {
	return c.cli.VolumeList(ctx, volume.ListOptions{})
}

// CreateVolume creates a new volume
func (c *Client) CreateVolume(ctx context.Context, config VolumeConfig) (volume.Volume, error) {
	return c.cli.VolumeCreate(ctx, volume.CreateOptions{
		Name:       config.Name,
		Driver:     config.Driver,
		Labels:     config.Labels,
		DriverOpts: config.DriverOpts,
	})
}

// RemoveVolume removes a volume
func (c *Client) RemoveVolume(ctx context.Context, volumeID string, force bool) error {
	return c.cli.VolumeRemove(ctx, volumeID, force)
}

// GetSystemInfo returns system-wide information
func (c *Client) GetSystemInfo(ctx context.Context) (system.Info, error) {
	return c.cli.Info(ctx)
}

// GetDiskUsage returns Docker disk usage information
func (c *Client) GetDiskUsage(ctx context.Context) (types.DiskUsage, error) {
	return c.cli.DiskUsage(ctx, types.DiskUsageOptions{})
}

// GetEvents returns Docker events
func (c *Client) GetEvents(ctx context.Context, options EventOptions) (io.ReadCloser, error) {
	resp, errChan := c.cli.Events(ctx, events.ListOptions{
		Since:   options.Since,
		Until:   options.Until,
		Filters: options.Filters,
	})

	// Convert the channel to a reader
	r, w := io.Pipe()
	go func() {
		defer w.Close()
		for {
			select {
			case event, ok := <-resp:
				if !ok {
					return
				}
				// Write event data to pipe
				w.Write([]byte(fmt.Sprintf("%v\n", event)))
			case err := <-errChan:
				if err != nil {
					w.CloseWithError(err)
					return
				}
			case <-ctx.Done():
				return
			}
		}
	}()
	return r, nil
}

// ExecCreate creates an exec instance in a container
func (c *Client) ExecCreate(ctx context.Context, containerID string, config ExecConfig) (types.IDResponse, error) {
	return c.cli.ContainerExecCreate(ctx, containerID, container.ExecOptions{
		Cmd:          config.Cmd,
		Env:          config.Env,
		WorkingDir:   config.WorkingDir,
		User:         config.User,
		AttachStdin:  config.AttachStdin,
		AttachStdout: config.AttachStdout,
		AttachStderr: config.AttachStderr,
		Tty:          config.Tty,
	})
}

// ExecStart starts an exec instance
func (c *Client) ExecStart(ctx context.Context, execID string, config ExecStartConfig) error {
	return c.cli.ContainerExecStart(ctx, execID, container.ExecStartOptions{
		Detach: config.Detach,
		Tty:    config.Tty,
	})
}

// ExecInspect returns information about an exec instance
func (c *Client) ExecInspect(ctx context.Context, execID string) (container.ExecInspect, error) {
	return c.cli.ContainerExecInspect(ctx, execID)
}

// ExecRun runs a command in a container and returns its combined
// stdout/stderr output and exit code.
func (c *Client) ExecRun(ctx context.Context, containerID string, cmd []string) (string, int, error) {
	exec, err := c.cli.ContainerExecCreate(ctx, containerID, container.ExecOptions{
		Cmd:          cmd,
		AttachStdout: true,
		AttachStderr: true,
	})
	if err != nil {
		return "", -1, err
	}

	resp, err := c.cli.ContainerExecAttach(ctx, exec.ID, container.ExecAttachOptions{})
	if err != nil {
		return "", -1, err
	}
	defer resp.Close()

	var buf bytes.Buffer
	if _, err := stdcopy.StdCopy(&buf, &buf, resp.Reader); err != nil {
		return "", -1, err
	}

	inspect, err := c.cli.ContainerExecInspect(ctx, exec.ID)
	if err != nil {
		return buf.String(), -1, err
	}
	return buf.String(), inspect.ExitCode, nil
}

// ExecAttach attaches to a running exec instance, returning the hijacked
// bidirectional stream. With Tty enabled the stream carries raw pty data
// (no stdcopy multiplexing).
func (c *Client) ExecAttach(ctx context.Context, execID string) (types.HijackedResponse, error) {
	return c.cli.ContainerExecAttach(ctx, execID, container.ExecAttachOptions{})
}

// ExecResize resizes the pty of a running exec instance.
func (c *Client) ExecResize(ctx context.Context, execID string, cols, rows uint) error {
	return c.cli.ContainerExecResize(ctx, execID, container.ResizeOptions{
		Height: rows,
		Width:  cols,
	})
}

// GetImageInfo returns information about a Docker image
func (c *Client) GetImageInfo(ctx context.Context, imageName string) (*ImageInfo, error) {
	images, err := c.cli.ImageList(ctx, image.ListOptions{})
	if err != nil {
		return nil, err
	}

	for _, img := range images {
		for _, tag := range img.RepoTags {
			if tag == imageName || tag == imageName+":latest" {
				return &ImageInfo{
					ID:          img.ID,
					RepoTags:    img.RepoTags,
					Size:        img.Size,
					Created:     img.Created,
					Labels:      img.Labels,
					RepoDigests: img.RepoDigests,
					Digest:      getDigestFromRepoTags(img.RepoDigests),
				}, nil
			}
		}
	}

	return nil, fmt.Errorf("image not found: %s", imageName)
}

// PushImage pushes an image to a registry
func (c *Client) PushImage(ctx context.Context, imageName, registryURL string) error {
	auth := registry.AuthConfig{}
	authStr, _ := registry.EncodeAuthConfig(auth)

	_, err := c.cli.ImagePush(ctx, imageName, image.PushOptions{
		RegistryAuth: authStr,
	})
	return err
}

// Close closes the Docker client connection
func (c *Client) Close() error {
	return c.cli.Close()
}

// Helper function to extract digest from repo digests
func getDigestFromRepoTags(digests []string) string {
	if len(digests) > 0 {
		return digests[0]
	}
	return ""
}