package oci

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/kubernetes-incubator/ocid/utils"
	"github.com/opencontainers/runtime-spec/specs-go"
)

// New creates a new Runtime with options provided
func New(runtimePath string, containerDir string) (*Runtime, error) {
	r := &Runtime{
		name:         filepath.Base(runtimePath),
		path:         runtimePath,
		containerDir: containerDir,
	}
	return r, nil
}

// Runtime stores the information about a oci runtime
type Runtime struct {
	name         string
	path         string
	containerDir string
}

// Name returns the name of the OCI Runtime
func (r *Runtime) Name() string {
	return r.name
}

// Path returns the full path the OCI Runtime executable
func (r *Runtime) Path() string {
	return r.path
}

// ContainerDir returns the path to the base directory for storing container configurations
func (r *Runtime) ContainerDir() string {
	return r.containerDir
}

// Version returns the version of the OCI Runtime
func (r *Runtime) Version() (string, error) {
	runtimeVersion, err := getOCIVersion(r.path, "-v")
	if err != nil {
		return "", err
	}
	return runtimeVersion, nil
}

func getOCIVersion(name string, args ...string) (string, error) {
	out, err := utils.ExecCmd(name, args...)
	if err != nil {
		return "", err
	}

	firstLine := out[:strings.Index(out, "\n")]
	v := firstLine[strings.LastIndex(firstLine, " ")+1:]
	return v, nil
}

// CreateContainer creates a container.
func (r *Runtime) CreateContainer(c *Container) error {
	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "--systemd-cgroup", "create", "--bundle", c.bundlePath, c.name)
}

// StartContainer starts a container.
func (r *Runtime) StartContainer(c *Container) error {
	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "start", c.name); err != nil {
		return err
	}
	c.state.Started = time.Now()
	return nil
}

// StopContainer stops a container.
func (r *Runtime) StopContainer(c *Container) error {
	// TODO: Check if it is still running after some time and send SIGKILL
	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "kill", c.name)
}

// DeleteContainer deletes a container.
func (r *Runtime) DeleteContainer(c *Container) error {
	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "delete", c.name)
}

// updateStatus refreshes the status of the container.
func (r *Runtime) UpdateStatus(c *Container) error {
	out, err := exec.Command(r.path, "state", c.name).Output()
	if err != nil {
		return fmt.Errorf("error getting container state for %s: %s", c.name, err)
	}
	stateReader := bytes.NewReader(out)
	if err := json.NewDecoder(stateReader).Decode(&c.state); err != nil {
		return fmt.Errorf("failed to decode container status for %s: %s", c.name, err)
	}
	return nil
}

// ContainerStatus returns the state of a container.
func (r *Runtime) ContainerStatus(c *Container) *ContainerState {
	return c.state
}

// Container respresents a runtime container.
type Container struct {
	name       string
	bundlePath string
	logPath    string
	labels     map[string]string
	sandbox    string
	state      *ContainerState
}

// ContainerStatus represents the status of a container.
type ContainerState struct {
	specs.State
	Created time.Time `json:"created"`
	Started time.Time `json:"started"`
}

// NewContainer creates a container object.
func NewContainer(name string, bundlePath string, logPath string, labels map[string]string, sandbox string) (*Container, error) {
	c := &Container{
		name:       name,
		bundlePath: bundlePath,
		logPath:    logPath,
		labels:     labels,
		sandbox:    sandbox,
	}
	return c, nil
}

// Name returns the name of the container.
func (c *Container) Name() string {
	return c.name
}

// BundlePath returns the bundlePath of the container.
func (c *Container) BundlePath() string {
	return c.bundlePath
}

// LogPath returns the log path of the container.
func (c *Container) LogPath() string {
	return c.logPath
}

// Labels returns the labels of the container.
func (c *Container) Labels() map[string]string {
	return c.labels
}

// Sandbox returns the sandbox name of the container.
func (c *Container) Sandbox() string {
	return c.sandbox
}

// NetNsPath returns the path to the network namespace of the container.
func (c *Container) NetNsPath() (string, error) {
	if c.state == nil {
		return "", fmt.Errorf("container state is not populated")
	}
	return fmt.Sprintf("/proc/%d/ns/net", c.state.Pid), nil
}