package initialize

import (
	"errors"
	"fmt"
	"log"
	"path"

	"github.com/coreos/coreos-cloudinit/third_party/launchpad.net/goyaml"

	"github.com/coreos/coreos-cloudinit/system"
)

// CloudConfigFile represents a CoreOS specific configuration option that can generate
// an associated system.File to be written to disk
type CloudConfigFile interface {
	// File should either return (*system.File, error), or (nil, nil) if nothing
	// needs to be done for this configuration option.
	File(root string) (*system.File, error)
}

// CloudConfigUnit represents a CoreOS specific configuration option that can generate
// an associated system.Unit to be created/enabled appropriately
type CloudConfigUnit interface {
	// Unit should either return (*system.Unit, error), or (nil, nil) if nothing
	// needs to be done for this configuration option.
	Unit(root string) (*system.Unit, error)
}

// CloudConfig encapsulates the entire cloud-config configuration file and maps directly to YAML
type CloudConfig struct {
	SSHAuthorizedKeys []string `yaml:"ssh_authorized_keys"`
	Coreos            struct {
		Etcd   EtcdEnvironment
		Fleet  FleetEnvironment
		OEM    OEMRelease
		Update UpdateConfig
		Units  []system.Unit
	}
	WriteFiles     []system.File `yaml:"write_files"`
	Hostname       string
	Users          []system.User
	ManageEtcHosts EtcHosts `yaml:"manage_etc_hosts"`
}

func NewCloudConfig(contents string) (*CloudConfig, error) {
	var cfg CloudConfig
	err := goyaml.Unmarshal([]byte(contents), &cfg)
	return &cfg, err
}

func (cc CloudConfig) String() string {
	bytes, err := goyaml.Marshal(cc)
	if err != nil {
		return ""
	}

	stringified := string(bytes)
	stringified = fmt.Sprintf("#cloud-config\n%s", stringified)

	return stringified
}

// Apply renders a CloudConfig to an Environment. This can involve things like
// configuring the hostname, adding new users, writing various configuration
// files to disk, and manipulating systemd services.
func Apply(cfg CloudConfig, env *Environment) error {
	if cfg.Hostname != "" {
		if err := system.SetHostname(cfg.Hostname); err != nil {
			return err
		}
		log.Printf("Set hostname to %s", cfg.Hostname)
	}

	for _, user := range cfg.Users {
		if user.Name == "" {
			log.Printf("User object has no 'name' field, skipping")
			continue
		}

		if system.UserExists(&user) {
			log.Printf("User '%s' exists, ignoring creation-time fields", user.Name)
			if user.PasswordHash != "" {
				log.Printf("Setting '%s' user's password", user.Name)
				if err := system.SetUserPassword(user.Name, user.PasswordHash); err != nil {
					log.Printf("Failed setting '%s' user's password: %v", user.Name, err)
					return err
				}
			}
		} else {
			log.Printf("Creating user '%s'", user.Name)
			if err := system.CreateUser(&user); err != nil {
				log.Printf("Failed creating user '%s': %v", user.Name, err)
				return err
			}
		}

		if len(user.SSHAuthorizedKeys) > 0 {
			log.Printf("Authorizing %d SSH keys for user '%s'", len(user.SSHAuthorizedKeys), user.Name)
			if err := system.AuthorizeSSHKeys(user.Name, env.SSHKeyName(), user.SSHAuthorizedKeys); err != nil {
				return err
			}
		}
		if user.SSHImportGithubUser != "" {
			log.Printf("Authorizing github user %s SSH keys for CoreOS user '%s'", user.SSHImportGithubUser, user.Name)
			if err := SSHImportGithubUser(user.Name, user.SSHImportGithubUser); err != nil {
				return err
			}
		}
		if user.SSHImportURL != "" {
			log.Printf("Authorizing SSH keys for CoreOS user '%s' from '%s'", user.Name, user.SSHImportURL)
			if err := SSHImportKeysFromURL(user.Name, user.SSHImportURL); err != nil {
				return err
			}
		}
	}

	if len(cfg.SSHAuthorizedKeys) > 0 {
		err := system.AuthorizeSSHKeys("core", env.SSHKeyName(), cfg.SSHAuthorizedKeys)
		if err == nil {
			log.Printf("Authorized SSH keys for core user")
		} else {
			return err
		}
	}

	for _, ccf := range []CloudConfigFile{cfg.Coreos.OEM, cfg.Coreos.Update, cfg.ManageEtcHosts} {
		f, err := ccf.File(env.Root())
		if err != nil {
			return err
		}
		if f != nil {
			cfg.WriteFiles = append(cfg.WriteFiles, *f)
		}
	}

	for _, ccu := range []CloudConfigUnit{cfg.Coreos.Etcd, cfg.Coreos.Fleet, cfg.Coreos.Update} {
		u, err := ccu.Unit(env.Root())
		if err != nil {
			return err
		}
		if u != nil {
			cfg.Coreos.Units = append(cfg.Coreos.Units, *u)
		}
	}

	for _, file := range cfg.WriteFiles {
		file.Path = path.Join(env.Root(), file.Path)
		if err := system.WriteFile(&file); err != nil {
			return err
		}
		log.Printf("Wrote file %s to filesystem", file.Path)
	}

	commands := make(map[string]string, 0)
	reload := false
	for _, unit := range cfg.Coreos.Units {
		dst := system.UnitDestination(&unit, env.Root())
		if unit.Content != "" {
			log.Printf("Writing unit %s to filesystem at path %s", unit.Name, dst)
			if err := system.PlaceUnit(&unit, dst); err != nil {
				return err
			}
			log.Printf("Placed unit %s at %s", unit.Name, dst)
			reload = true
		}

		if unit.Mask {
			log.Printf("Masking unit file %s", unit.Name)
			if err := system.MaskUnit(unit.Name, env.Root()); err != nil {
				return err
			}
		}

		if unit.Enable {
			if unit.Group() != "network" {
				log.Printf("Enabling unit file %s", dst)
				if err := system.EnableUnitFile(dst, unit.Runtime); err != nil {
					return err
				}
				log.Printf("Enabled unit %s", unit.Name)
			} else {
				log.Printf("Skipping enable for network-like unit %s", unit.Name)
			}
		}

		if unit.Group() == "network" {
			commands["systemd-networkd.service"] = "restart"
		} else if unit.Command != "" {
			commands[unit.Name] = unit.Command
		}
	}

	if reload {
		if err := system.DaemonReload(); err != nil {
			return errors.New(fmt.Sprintf("failed systemd daemon-reload: %v", err))
		}
	}

	for unit, command := range commands {
		log.Printf("Calling unit command '%s %s'", command, unit)
		res, err := system.RunUnitCommand(command, unit)
		if err != nil {
			return err
		}
		log.Printf("Result of '%s %s': %s", command, unit, res)
	}

	return nil
}