package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"sort"
	"strings"
	"time"

	"github.com/Luzifer/rconfig/v2"
	"github.com/hashicorp/vault/api"
	homedir "github.com/mitchellh/go-homedir"
	"github.com/sethgrid/curse"
)

var (
	cfg = struct {
		Field          string `flag:"field" default:"secret" description:"Field inside the key to search the TOTP secret in"`
		NoTime         bool   `flag:"no-time,n" default:"false" description:"Omit printing the validity time"`
		OneShot        bool   `flag:"one-shot,1" default:"false" description:"Prints token only once instead continuously"`
		TestSecret     string `flag:"test" default:"" description:"Use a test secret from CLI instead of using a secret from Vault"`
		VaultAddress   string `flag:"vault-addr" env:"VAULT_ADDR" default:"https://127.0.0.1:8200" description:"Vault API address"`
		VaultToken     string `flag:"vault-token" env:"VAULT_TOKEN" vardefault:"vault-token" description:"Vault Token to use for accessing Vault instance"`
		VersionAndExit bool   `flag:"version" default:"false" description:"Prints current version and exits"`
	}{}

	version = "dev"
)

func vaultTokenFromDisk() string {
	vf, err := homedir.Expand("~/.vault-token")
	if err != nil {
		return ""
	}

	data, err := ioutil.ReadFile(vf)
	if err != nil {
		return ""
	}

	return string(data)
}

func init() {
	rconfig.SetVariableDefaults(map[string]string{
		"vault-token": vaultTokenFromDisk(),
	})

	if err := rconfig.Parse(&cfg); err != nil {
		log.Fatalf("Unable to parse commandline options: %s", err)
	}

	if cfg.VersionAndExit {
		fmt.Printf("vault-totp %s\n", version)
		os.Exit(0)
	}

	if cfg.VaultToken == "" && cfg.TestSecret == "" {
		log.Fatalf("You need to specify a vault-token")
	}
}

func main() {
	if len(rconfig.Args()) < 2 && cfg.TestSecret == "" {
		log.Fatalf("Please specify a vault key to read the secret from.\n\nUsage: vault-totp [opts] <vault-key>")
	}

	var (
		secrets []token
		err     error
	)

	if cfg.TestSecret == "" {
		secrets, err = getSecretsFromVault()
		if err != nil {
			log.Fatalf("Error to retrieve secret: %s", err)
		}
	} else {
		secrets = []token{{Name: "Test", Secret: cfg.TestSecret}}
	}

	sort.Sort(tokenList(secrets))

	output, err := curse.New()
	if err != nil {
		log.Fatal(err)
	}

	firstRun := true
	for range time.Tick(250 * time.Millisecond) {
		if !firstRun {
			output.MoveUp(len(secrets))
		}

		for _, s := range secrets {
			output.EraseCurrentLine()
			o, err := s.BuildOutput(len(secrets) > 1, tokenList(secrets).LongestName())
			if err != nil {
				fmt.Printf("%s: ERROR (%s)\n", s.Name, err)
				continue
			}

			fmt.Println(o)
		}

		if cfg.OneShot {
			break
		}

		firstRun = false
	}
}

func getSecretsFromVault() ([]token, error) {
	client, err := api.NewClient(&api.Config{
		Address: cfg.VaultAddress,
	})
	if err != nil {
		return nil, fmt.Errorf("Unable to create client: %s", err)
	}

	client.SetToken(cfg.VaultToken)

	resp := []token{}
	keyPool := []string{}

	key := rconfig.Args()[1]

	if strings.HasSuffix(key, "*") {
		scanPool := []string{strings.TrimRight(key, "*")}

		for len(scanPool) > 0 {
			s, err := client.Logical().List(scanPool[0])
			if err != nil {
				return nil, fmt.Errorf("Unable to list keys %q: %s", key, err)
			}

			if s == nil {
				return nil, fmt.Errorf("There is no key %q", scanPool[0])
			}

			if s.Data["keys"] != nil {
				for _, sk := range s.Data["keys"].([]interface{}) {
					sks := sk.(string)
					if strings.HasSuffix(sks, "/") {
						scanPool = append(scanPool, scanPool[0]+sks)
					} else {
						keyPool = append(keyPool, scanPool[0]+sks)
					}
				}
			}

			scanPool = scanPool[1:]
		}

	} else {
		keyPool = append(keyPool, key)
	}

	for _, k := range keyPool {
		data, err := client.Logical().Read(k)
		if err != nil {
			return nil, fmt.Errorf("Unable to read from key %q: %s", k, err)
		}

		if data == nil {
			return nil, fmt.Errorf("Key %q not found", k)
		}

		if data.Data[cfg.Field] == nil {
			return nil, fmt.Errorf("The key %q does not have a field named %q.", k, cfg.Field)
		}

		name := k
		if data.Data["name"] != nil {
			name = data.Data["name"].(string)
		}

		resp = append(resp, token{Name: name, Secret: data.Data[cfg.Field].(string)})
	}

	return resp, nil
}