package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"regexp"
	"time"

	"golang.org/x/crypto/ssh"
)

type Config struct {
	Zfsnap   map[string]string `json:"zfsnap"`
	Box      map[string]*Box   `json:"box"`
	Email    EmailConfig       `json:"email"`
	Apps     []AppConfig       `json:"apps"`
	Timezone string            `json:"timezone"`
	Now      time.Time         `json:"-"`
}

//Load config from file
func (c *Config) Load() error {
	if *debugFlag {
		log.Printf("SSHConfig.Load : Start")
	}
	b, err := ioutil.ReadFile(*cfgFile)
	if err != nil {
		if *debugFlag {
			log.Printf("Config.Load : ioutil.ReadFile(%s) : %s", *cfgFile, err)
		}
		return err
	}

	err = json.Unmarshal(b, &c)
	if err != nil {
		if *debugFlag {
			log.Printf("Config.Load : json.Unmarshal : %s", err)
		}
		return err
	}

	if *debugFlag {
		log.Printf("Config.Load :\r\n%v", cfg)
	}

	l, err := time.LoadLocation(cfg.Timezone)
	if err != nil {
		if *debugFlag {
			log.Printf("Config.Load : time.LoadLocation : %s", err)
		}
		return err
	}

	if len(cfg.Email.SmtpHost) == 0 {
		if *debugFlag {
			log.Printf("Config.Load : no smtp")
		}
		return fmt.Errorf("no smtp")
	}

	if len(cfg.Email.FromEmail) == 0 {
		if *debugFlag {
			log.Printf("Config.Load : no email from")
		}
		return fmt.Errorf("no email from")
	}

	if len(cfg.Email.ToEmail) == 0 {
		if *debugFlag {
			log.Printf("Config.Load : no email to")
		}
		return fmt.Errorf("no email to")
	}

	c.Now = time.Now().In(l)

	for k, v := range c.Box {
		v.Name = k
		v.online = false
		v.zfs = NewZFSConfig()
		s := &SSHConfig{
			logged: false,
			name:   k,
		}
		v.ssh = s
		keyRaw, err := ioutil.ReadFile(v.Key)
		if err != nil {
			if *debugFlag {
				log.Printf("Config.Load : ioutil.ReadFile(%s) : %s", k, err)
			}
			return err
		}

		key, err := ssh.ParseRawPrivateKey(keyRaw)
		if err != nil {
			if *debugFlag {
				log.Printf("Config.Load : ssh.ParseRawPrivateKey(%s) : %s", k, err)
			}
			return err
		}

		s.signer, err = ssh.NewSignerFromKey(key)
		if err != nil {
			if *debugFlag {
				log.Printf("Config.Load : ssh.NewSignerFromKey(%s) : %s", k, err)
			}
			return err
		}

		s.config = &ssh.ClientConfig{
			User: v.User,
			Auth: []ssh.AuthMethod{
				ssh.PublicKeys(s.signer),
			},
			HostKeyCallback: ssh.InsecureIgnoreHostKey(),
			Timeout:         5 * time.Second,
		}

		s.client, err = ssh.Dial("tcp", v.Addr, s.config)
		if err != nil {
			if *debugFlag {
				log.Printf("Config.Load : ssh.Dial(%s) : %s", k, err)
			}
		} else {
			v.online = true
			session, err := s.client.NewSession()
			if err != nil {
				if *debugFlag {
					log.Printf("Config.Load : client.NewSession(%s) : %s", k, err)
				}
				return err
			}

			var b bytes.Buffer
			session.Stdout = &b

			err = session.Run("TZ=\"" + cfg.Timezone + "\" zfsnap --version")
			if err != nil {
				if *debugFlag {
					log.Printf("Config.Load : client.NewSession(%s) : %s", k, err)
				}
				return err
			}
			if *debugFlag {
				log.Printf("Config.Load : logged into %s : %s", k, b.String())
			}
			session.Close()
			s.logged = true
		}
	}

	for _, app := range c.Apps {
		for _, src := range app.Sources {
			if !src.Valid() {
				return fmt.Errorf("Source not valid : %s", string(src))
			}
			if _, ok := cfg.Box[src.Box()]; !ok {
				return fmt.Errorf("No box defined for source : %s", string(src))
			}
			if !cfg.Box[src.Box()].online {
				email.items = append(email.items, fmt.Sprintf("Source box offline for app : %s", app.Name))
			}
		}
		var allOffline bool = true
		for _, dest := range app.Destinations {
			if !dest.Valid() {
				return fmt.Errorf("Destination not valid : %s", string(dest))
			}
			if _, ok := cfg.Box[dest.Box()]; !ok {
				return fmt.Errorf("No box defined for destination : %s", string(dest))
			}
			if cfg.Box[dest.Box()].online {
				allOffline = false
			}
		}
		if allOffline {
			email.items = append(email.items, fmt.Sprintf("No online destination box for app : %s", app.Name))
		}

		for val, before := range app.Before {
			_, err = regexp.Compile(val)
			if err != nil {
				if *debugFlag {
					log.Printf("Config.Load : invalid regex : %s", val)
				}
				return err
			}
			if !before.Valid() {
				return fmt.Errorf("Before not valid : %s", string(before))
			}
			if _, ok := cfg.Box[before.Box()]; !ok {
				return fmt.Errorf("No box defined for before : %s", string(before))
			}
			if !cfg.Box[before.Box()].online {
				email.items = append(email.items, fmt.Sprintf("Before box offline for app : %s", app.Name))
			}
		}
		for val, after := range app.After {
			_, err = regexp.Compile(val)
			if err != nil {
				if *debugFlag {
					log.Printf("Config.Load : invalid regex : %s", val)
				}
				return err
			}
			if !after.Valid() {
				return fmt.Errorf("After not valid : %s", string(after))
			}
			if _, ok := cfg.Box[after.Box()]; !ok {
				return fmt.Errorf("No box defined for after : %s", string(after))
			}
			if !cfg.Box[after.Box()].online {
				email.items = append(email.items, fmt.Sprintf("After box offline for app : %s", app.Name))
			}
		}
	}

	return nil
}

//Close config
func (c *Config) Close() error {
	return nil
}