package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"runtime"

	"github.com/docker/docker/pkg/system"
	"github.com/ghodss/yaml"
	"github.com/urfave/cli"
)

var (
	infoDescription = "display system information"
	infoCommand     = cli.Command{
		Name:        "info",
		Usage:       infoDescription,
		Description: `Information display here pertain to the host, current storage stats, and build of kpod. Useful for the user and when reporting issues.`,
		Flags:       infoFlags,
		Action:      infoCmd,
		ArgsUsage:   "",
	}
	infoFlags = []cli.Flag{
		cli.BoolFlag{
			Name:  "debug, D",
			Usage: "display additional debug information",
		},
		cli.BoolFlag{
			Name:  "json",
			Usage: "output as JSON instead of the default YAML",
		},
	}
)

func infoCmd(c *cli.Context) error {
	info := map[string]interface{}{}

	infoGivers := []infoGiverFunc{
		storeInfo,
		hostInfo,
	}

	if c.Bool("debug") {
		infoGivers = append(infoGivers, debugInfo)
	}

	for _, giver := range infoGivers {
		thisName, thisInfo, err := giver(c)
		if err != nil {
			info[thisName] = infoErr(err)
			continue
		}
		info[thisName] = thisInfo
	}

	var buf []byte
	var err error
	if c.Bool("json") {
		buf, err = json.MarshalIndent(info, "", "  ")
	} else {
		buf, err = yaml.Marshal(info)
	}
	if err != nil {
		return err
	}
	fmt.Println(string(buf))

	return nil
}

func infoErr(err error) map[string]interface{} {
	return map[string]interface{}{
		"error": err.Error(),
	}
}

type infoGiverFunc func(c *cli.Context) (name string, info map[string]interface{}, err error)

// top-level "debug" info
func debugInfo(c *cli.Context) (string, map[string]interface{}, error) {
	info := map[string]interface{}{}
	info["compiler"] = runtime.Compiler
	info["go version"] = runtime.Version()
	return "debug", info, nil
}

// top-level "host" info
func hostInfo(c *cli.Context) (string, map[string]interface{}, error) {
	// lets say OS, arch, number of cpus, amount of memory, maybe os distribution/version, hostname, kernel version, uptime
	info := map[string]interface{}{}
	info["os"] = runtime.GOOS
	info["arch"] = runtime.GOARCH
	info["cpus"] = runtime.NumCPU()
	mi, err := system.ReadMemInfo()
	if err != nil {
		info["meminfo"] = infoErr(err)
	} else {
		// TODO this might be a place for github.com/dustin/go-humanize
		info["MemTotal"] = mi.MemTotal
		info["MemFree"] = mi.MemFree
		info["SwapTotal"] = mi.SwapTotal
		info["SwapFree"] = mi.SwapFree
	}
	if kv, err := readKernelVersion(); err != nil {
		info["kernel"] = infoErr(err)
	} else {
		info["kernel"] = kv
	}

	if up, err := readUptime(); err != nil {
		info["uptime"] = infoErr(err)
	} else {
		info["uptime"] = up
	}
	if host, err := os.Hostname(); err != nil {
		info["hostname"] = infoErr(err)
	} else {
		info["hostname"] = host
	}
	return "host", info, nil
}

// top-level "store" info
func storeInfo(c *cli.Context) (string, map[string]interface{}, error) {
	store, err := getStore(c)
	if err != nil {
		return "store", nil, err
	}

	// lets say storage driver in use, number of images, number of containers
	info := map[string]interface{}{}
	info["GraphRoot"] = store.GraphRoot()
	info["GraphDriverName"] = store.GraphDriverName()
	if is, err := store.ImageStore(); err != nil {
		info["ImageStore"] = infoErr(err)
	} else {
		images, err := is.Images()
		if err != nil {
			info["ImageStore"] = infoErr(err)
		} else {
			info["ImageStore"] = map[string]interface{}{
				"number": len(images),
			}
		}
	}
	/* Oh this is in master on containers/storage, rebase later
	if is, err := store.ROImageStores(); err != nil {
		info["ROImageStore"] = infoErr(err)
	} else {
		images, err := is.Images()
		if err != nil {
			info["ROImageStore"] = infoErr(err)
		} else {
			info["ROImageStore"] = map[string]interface{}{
				"number": len(images),
			}
		}
	}
	*/
	if cs, err := store.ContainerStore(); err != nil {
		info["ContainerStore"] = infoErr(err)
	} else {
		containers, err := cs.Containers()
		if err != nil {
			info["ContainerStore"] = infoErr(err)
		} else {
			info["ContainerStore"] = map[string]interface{}{
				"number": len(containers),
			}
		}
	}
	return "store", info, nil
}

func readKernelVersion() (string, error) {
	buf, err := ioutil.ReadFile("/proc/version")
	if err != nil {
		return "", err
	}
	f := bytes.Fields(buf)
	if len(f) < 2 {
		return string(bytes.TrimSpace(buf)), nil
	}
	return string(f[2]), nil
}

func readUptime() (string, error) {
	buf, err := ioutil.ReadFile("/proc/uptime")
	if err != nil {
		return "", err
	}
	f := bytes.Fields(buf)
	if len(f) < 1 {
		return "", fmt.Errorf("invalid uptime")
	}
	return string(f[0]), nil
}