package initialize

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

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

	"github.com/coreos/coreos-cloudinit/network"
	"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
// associated system.Units to be created/enabled appropriately
type CloudConfigUnit interface {
	Units(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"`
	NetworkConfigPath string
	NetworkConfig     string
}

type warner func(format string, v ...interface{})

// warnOnUnrecognizedKeys parses the contents of a cloud-config file and calls
// warn(msg, key) for every unrecognized key (i.e. those not present in CloudConfig)
func warnOnUnrecognizedKeys(contents string, warn warner) {
	// Generate a map of all understood cloud config options
	var cc map[string]interface{}
	b, _ := goyaml.Marshal(&CloudConfig{})
	goyaml.Unmarshal(b, &cc)

	// Now unmarshal the entire provided contents
	var c map[string]interface{}
	goyaml.Unmarshal([]byte(contents), &c)

	// Check that every key in the contents exists in the cloud config
	for k, _ := range c {
		if _, ok := cc[k]; !ok {
			warn("Warning: unrecognized key %q in provided cloud config - ignoring section", k)
		}
	}

	// Check for unrecognized coreos options, if any are set
	if coreos, ok := c["coreos"]; ok {
		if set, ok := coreos.(map[interface{}]interface{}); ok {
			known := cc["coreos"].(map[interface{}]interface{})
			for k, _ := range set {
				if key, ok := k.(string); ok {
					if _, ok := known[key]; !ok {
						warn("Warning: unrecognized key %q in coreos section of provided cloud config - ignoring", key)
					}
				} else {
					warn("Warning: unrecognized key %q in coreos section of provided cloud config - ignoring", k)
				}
			}
		}
	}

	// Check for any badly-specified users, if any are set
	if users, ok := c["users"]; ok {
		var known map[string]interface{}
		b, _ := goyaml.Marshal(&system.User{})
		goyaml.Unmarshal(b, &known)

		if set, ok := users.([]interface{}); ok {
			for _, u := range set {
				if user, ok := u.(map[interface{}]interface{}); ok {
					for k, _ := range user {
						if key, ok := k.(string); ok {
							if _, ok := known[key]; !ok {
								warn("Warning: unrecognized key %q in user section of cloud config - ignoring", key)
							}
						} else {
							warn("Warning: unrecognized key %q in user section of cloud config - ignoring", k)
						}
					}
				}
			}
		}
	}

	// Check for any badly-specified files, if any are set
	if files, ok := c["write_files"]; ok {
		var known map[string]interface{}
		b, _ := goyaml.Marshal(&system.File{})
		goyaml.Unmarshal(b, &known)

		if set, ok := files.([]interface{}); ok {
			for _, f := range set {
				if file, ok := f.(map[interface{}]interface{}); ok {
					for k, _ := range file {
						if key, ok := k.(string); ok {
							if _, ok := known[key]; !ok {
								warn("Warning: unrecognized key %q in file section of cloud config - ignoring", key)
							}
						} else {
							warn("Warning: unrecognized key %q in file section of cloud config - ignoring", k)
						}
					}
				}
			}
		}
	}
}

// NewCloudConfig instantiates a new CloudConfig from the given contents (a
// string of YAML), returning any error encountered. It will ignore unknown
// fields but log encountering them.
func NewCloudConfig(contents string) (*CloudConfig, error) {
	var cfg CloudConfig
	err := goyaml.Unmarshal([]byte(contents), &cfg)
	if err != nil {
		return &cfg, err
	}
	warnOnUnrecognizedKeys(contents, log.Printf)
	return &cfg, nil
}

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.Units(env.Root())
		if err != nil {
			return err
		}
		cfg.Coreos.Units = append(cfg.Coreos.Units, u...)
	}

	wroteEnvironment := false
	for _, file := range cfg.WriteFiles {
		fullPath, err := system.WriteFile(&file, env.Root())
		if err != nil {
			return err
		}
		if path.Clean(file.Path) == "/etc/environment" {
			wroteEnvironment = true
		}
		log.Printf("Wrote file %s to filesystem", fullPath)
	}

	if !wroteEnvironment {
		ef := env.DefaultEnvironmentFile()
		if ef != nil {
			err := system.WriteEnvFile(ef, env.Root())
			if err != nil {
				return err
			}
			log.Printf("Updated /etc/environment")
		}
	}

	if env.NetconfType() != "" {
		var interfaces []network.InterfaceGenerator
		var err error
		switch env.NetconfType() {
		case "debian":
			interfaces, err = network.ProcessDebianNetconf(cfg.NetworkConfig)
		case "digitalocean":
			interfaces, err = network.ProcessDigitalOceanNetconf(cfg.NetworkConfig)
		default:
			return fmt.Errorf("Unsupported network config format %q", env.NetconfType())
		}

		if err != nil {
			return err
		}

		if err := system.WriteNetworkdConfigs(interfaces); err != nil {
			return err
		}
		if err := system.RestartNetwork(interfaces); err != nil {
			return err
		}
	}

	um := system.NewUnitManager(env.Root())
	return processUnits(cfg.Coreos.Units, env.Root(), um)

}

// processUnits takes a set of Units and applies them to the given root using
// the given UnitManager. This can involve things like writing unit files to
// disk, masking/unmasking units, or invoking systemd
// commands against units. It returns any error encountered.
func processUnits(units []system.Unit, root string, um system.UnitManager) error {
	type action struct {
		unit    string
		command string
	}
	actions := make([]action, 0, len(units))
	reload := false
	for _, unit := range units {
		dst := unit.Destination(root)
		if unit.Content != "" {
			log.Printf("Writing unit %s to filesystem at path %s", unit.Name, dst)
			if err := um.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 := um.MaskUnit(&unit); err != nil {
				return err
			}
		} else if unit.Runtime {
			log.Printf("Ensuring runtime unit file %s is unmasked", unit.Name)
			if err := um.UnmaskUnit(&unit); err != nil {
				return err
			}
		}

		if unit.Enable {
			if unit.Group() != "network" {
				log.Printf("Enabling unit file %s", unit.Name)
				if err := um.EnableUnitFile(unit.Name, 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" {
			actions = append(actions, action{"systemd-networkd.service", "restart"})
		} else if unit.Command != "" {
			actions = append(actions, action{unit.Name, unit.Command})
		}
	}

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

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

	return nil
}