/*
   Copyright 2014 CoreOS, Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package initialize

import (
	"os"
	"path"
	"regexp"
	"strings"

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

const DefaultSSHKeyName = "coreos-cloudinit"

type Environment struct {
	root          string
	configRoot    string
	workspace     string
	netconfType   string
	sshKeyName    string
	substitutions map[string]string
}

// TODO(jonboulle): this is getting unwieldy, should be able to simplify the interface somehow
func NewEnvironment(root, configRoot, workspace, netconfType, sshKeyName string, substitutions map[string]string) *Environment {
	if substitutions == nil {
		substitutions = make(map[string]string)
	}
	// If certain values are not in the supplied substitution, fall back to retrieving them from the environment
	for k, v := range map[string]string{
		"$public_ipv4":  os.Getenv("COREOS_PUBLIC_IPV4"),
		"$private_ipv4": os.Getenv("COREOS_PRIVATE_IPV4"),
		"$public_ipv6":  os.Getenv("COREOS_PUBLIC_IPV6"),
		"$private_ipv6": os.Getenv("COREOS_PRIVATE_IPV6"),
	} {
		if _, ok := substitutions[k]; !ok {
			substitutions[k] = v
		}
	}
	return &Environment{root, configRoot, workspace, netconfType, sshKeyName, substitutions}
}

func (e *Environment) Workspace() string {
	return path.Join(e.root, e.workspace)
}

func (e *Environment) Root() string {
	return e.root
}

func (e *Environment) ConfigRoot() string {
	return e.configRoot
}

func (e *Environment) NetconfType() string {
	return e.netconfType
}

func (e *Environment) SSHKeyName() string {
	return e.sshKeyName
}

func (e *Environment) SetSSHKeyName(name string) {
	e.sshKeyName = name
}

// Apply goes through the map of substitutions and replaces all instances of
// the keys with their respective values. It supports escaping substitutions
// with a leading '\'.
func (e *Environment) Apply(data string) string {
	for key, val := range e.substitutions {
		matchKey := strings.Replace(key, `$`, `\$`, -1)
		replKey := strings.Replace(key, `$`, `$$`, -1)

		// "key" -> "val"
		data = regexp.MustCompile(`([^\\]|^)`+matchKey).ReplaceAllString(data, `${1}`+val)
		// "\key" -> "key"
		data = regexp.MustCompile(`\\`+matchKey).ReplaceAllString(data, replKey)
	}
	return data
}

func (e *Environment) DefaultEnvironmentFile() *system.EnvFile {
	ef := system.EnvFile{
		File: &system.File{File: config.File{
			Path: "/etc/environment",
		}},
		Vars: map[string]string{},
	}
	if ip, ok := e.substitutions["$public_ipv4"]; ok && len(ip) > 0 {
		ef.Vars["COREOS_PUBLIC_IPV4"] = ip
	}
	if ip, ok := e.substitutions["$private_ipv4"]; ok && len(ip) > 0 {
		ef.Vars["COREOS_PRIVATE_IPV4"] = ip
	}
	if ip, ok := e.substitutions["$public_ipv6"]; ok && len(ip) > 0 {
		ef.Vars["COREOS_PUBLIC_IPV6"] = ip
	}
	if ip, ok := e.substitutions["$private_ipv6"]; ok && len(ip) > 0 {
		ef.Vars["COREOS_PRIVATE_IPV6"] = ip
	}
	if len(ef.Vars) == 0 {
		return nil
	} else {
		return &ef
	}
}