// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package botanist

import (
	"context"
	"encoding/json"
	"fmt"
	"net"
	"os"
	"strings"
	"time"

	"fuchsia.googlesource.com/tools/netboot"
	"fuchsia.googlesource.com/tools/retry"
)

// StringsFlag implements flag.Value so it may be treated as a flag type.
type StringsFlag []string

// Set implements flag.Value.Set.
func (s *StringsFlag) Set(val string) error {
	*s = append(*s, val)
	return nil
}

// Strings implements flag.Value.String.
func (s *StringsFlag) String() string {
	if s == nil {
		return ""
	}
	return strings.Join([]string(*s), ", ")
}

// GetNodeAddress returns the UDP address corresponding to a given node, specifically
// the netsvc or fuchsia address dependending on the value of `fuchsia`.
func GetNodeAddress(ctx context.Context, nodename string, fuchsia bool) (*net.UDPAddr, error) {
	// Retry, as the netstack might not yet be up.
	var addr *net.UDPAddr
	var err error
	n := netboot.NewClient(time.Second)
	err = retry.Retry(ctx, retry.WithMaxDuration(&retry.ZeroBackoff{}, time.Minute), func() error {
		addr, err = n.Discover(nodename, fuchsia)
		return err
	}, nil)
	if err != nil {
		return nil, fmt.Errorf("cannot find node %q: %v", nodename, err)
	}
	return addr, nil
}

// DeviceProperties contains static properties of a hardware device.
type DeviceProperties struct {
	// Nodename is the hostname of the device that we want to boot on.
	Nodename string `json:"nodename"`

	// PDU is the configuration for the attached Power Distribution Unit.
	PDU *Config `json:"pdu,omitempty"`

	// SSHKeys are the default system keys to be used with the device.
	SSHKeys []string `json:"keys,omitempty"`
}

// LoadDeviceProperties unmarshalls the DeviceProperties found in a given file.
func LoadDeviceProperties(propertiesFile string, properties *DeviceProperties) error {
	file, err := os.Open(propertiesFile)
	if err != nil {
		return err
	}

	return json.NewDecoder(file).Decode(properties)
}