package main

import (
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path"

	log "github.com/Sirupsen/logrus"

	"github.com/docker/hyperkit/go"

	"github.com/docker/infrakit/pkg/spi/instance"
	"github.com/docker/infrakit/pkg/types"
)

// NewHyperKitPlugin creates an instance plugin for hyperkit.
func NewHyperKitPlugin(vmDir, hyperkit, vpnkitSock string) instance.Plugin {
	return &hyperkitPlugin{VMDir: vmDir,
		HyperKit:   hyperkit,
		VPNKitSock: vpnkitSock,
	}
}

type hyperkitPlugin struct {
	// VMDir is the path to a directory where per VM state is kept
	VMDir string

	// Hyperkit is the path to the hyperkit executable
	HyperKit string

	// VPNKitSock is the path to the VPNKit Unix domain socket.
	VPNKitSock string
}

// Validate performs local validation on a provision request.
func (p hyperkitPlugin) Validate(req *types.Any) error {
	return nil
}

// Provision creates a new instance.
func (p hyperkitPlugin) Provision(spec instance.Spec) (*instance.ID, error) {

	var properties map[string]interface{}

	if spec.Properties != nil {
		if err := spec.Properties.Decode(&properties); err != nil {
			return nil, fmt.Errorf("Invalid instance properties: %s", err)
		}
	}

	if properties["Moby"] == nil {
		return nil, errors.New("Property 'Moby' must be set")
	}
	if properties["CPUs"] == nil {
		properties["CPUs"] = 1
	}
	if properties["Memory"] == nil {
		properties["Memory"] = 512
	}
	if properties["Disk"] == nil {
		properties["Disk"] = 256
	}

	instanceDir, err := ioutil.TempDir(p.VMDir, "infrakit-")
	if err != nil {
		return nil, err
	}
	id := instance.ID(path.Base(instanceDir))

	// Start a HyperKit instance
	h, err := hyperkit.New(p.HyperKit, instanceDir, p.VPNKitSock, "")
	if err != nil {
		return nil, err
	}
	h.Kernel = properties["Moby"].(string) + "-bzImage"
	h.Initrd = properties["Moby"].(string) + "-initrd.img"
	h.CPUs = int(properties["CPUs"].(float64))
	h.Memory = int(properties["Memory"].(float64))
	h.DiskSize = int(properties["Disk"].(float64))
	h.UserData = spec.Init
	h.Console = hyperkit.ConsoleFile
	err = h.Start("console=ttyS0")
	if err != nil {
		return nil, err
	}
	log.Info("Started new VM: ", id)

	tagData, err := types.AnyValue(spec.Tags)
	if err != nil {
		return nil, err
	}

	if err := ioutil.WriteFile(path.Join(instanceDir, "tags"), tagData.Bytes(), 0644); err != nil {
		return nil, err
	}

	return &id, nil
}

// Label labels the instance
func (p hyperkitPlugin) Label(instance instance.ID, labels map[string]string) error {
	instanceDir := path.Join(p.VMDir, string(instance))
	tagFile := path.Join(instanceDir, "tags")
	buff, err := ioutil.ReadFile(tagFile)
	if err != nil {
		return err
	}

	tags := map[string]string{}
	err = types.AnyBytes(buff).Decode(&tags)
	if err != nil {
		return err
	}

	for k, v := range labels {
		tags[k] = v
	}

	encoded, err := types.AnyValue(tags)
	if err != nil {
		return err
	}
	return ioutil.WriteFile(tagFile, encoded.Bytes(), 0644)
}

// Destroy terminates an existing instance.
func (p hyperkitPlugin) Destroy(id instance.ID) error {
	log.Info("Destroying VM: ", id)

	instanceDir := path.Join(p.VMDir, string(id))
	_, err := os.Stat(instanceDir)
	if err != nil {
		if os.IsNotExist(err) {
			return errors.New("Instance does not exist")
		}
	}

	h, err := hyperkit.FromState(instanceDir)
	if err != nil {
		return err
	}
	err = h.Stop()
	if err != nil {
		return err
	}
	err = h.Remove(false)
	if err != nil {
		return err
	}
	return nil
}

// DescribeInstances returns descriptions of all instances matching all of the provided tags.
func (p hyperkitPlugin) DescribeInstances(tags map[string]string) ([]instance.Description, error) {
	files, err := ioutil.ReadDir(p.VMDir)
	if err != nil {
		return nil, err
	}

	descriptions := []instance.Description{}

	for _, file := range files {
		if !file.IsDir() {
			continue
		}

		instanceDir := path.Join(p.VMDir, file.Name())

		tagData, err := ioutil.ReadFile(path.Join(instanceDir, "tags"))
		if err != nil {
			if os.IsNotExist(err) {
				continue
			}

			return nil, err
		}

		instanceTags := map[string]string{}
		if err := types.AnyBytes(tagData).Decode(&instanceTags); err != nil {
			return nil, err
		}

		allMatched := true
		for k, v := range tags {
			value, exists := instanceTags[k]
			if !exists || v != value {
				allMatched = false
				break
			}
		}

		if allMatched {
			var logicalID *instance.LogicalID
			id := instance.ID(file.Name())

			h, err := hyperkit.FromState(instanceDir)
			if err != nil {
				log.Warningln("Could not get instance data. Id: ", id)
				p.Destroy(id)
				continue
			}
			if !h.IsRunning() {
				log.Warningln("Instance is not running. Id: ", id)
				p.Destroy(id)
				continue
			}
			lid := instance.LogicalID(h.Pid)
			logicalID = &lid

			descriptions = append(descriptions, instance.Description{
				ID:        id,
				LogicalID: logicalID,
				Tags:      instanceTags,
			})
		}
	}

	return descriptions, nil
}