//go:generate struct-markdown
//go:generate mapstructure-to-hcl2 -type Config

package lxc

import (
	"fmt"
	"os"
	"time"

	"github.com/hashicorp/packer/common"
	"github.com/hashicorp/packer/helper/config"
	"github.com/hashicorp/packer/packer"
	"github.com/hashicorp/packer/template/interpolate"
	"github.com/mitchellh/mapstructure"
)

type Config struct {
	common.PackerConfig `mapstructure:",squash"`
	// The path to the lxc configuration file.
	ConfigFile string `mapstructure:"config_file" required:"true"`
	// The directory in which to save the exported
	// tar.gz. Defaults to output-<BuildName> in the current directory.
	OutputDir string `mapstructure:"output_directory" required:"false"`
	// The name of the LXC container. Usually stored
	// in /var/lib/lxc/containers/<container_name>. Defaults to
	// packer-<BuildName>.
	ContainerName string `mapstructure:"container_name" required:"false"`
	// Allows you to specify a wrapper command, such
	// as ssh so you can execute packer builds on a remote host. Defaults to
	// `{{.Command}}`; i.e. no wrapper.
	CommandWrapper string `mapstructure:"command_wrapper" required:"false"`
	// The timeout in seconds to wait for the the
	// container to start. Defaults to 20 seconds.
	InitTimeout time.Duration `mapstructure:"init_timeout" required:"false"`

	// Options to pass to lxc-create. For
	// instance, you can specify a custom LXC container configuration file with
	// ["-f", "/path/to/lxc.conf"]. Defaults to []. See man 1 lxc-create for
	// available options.
	CreateOptions []string `mapstructure:"create_options" required:"false"`
	// Options to pass to lxc-start. For
	// instance, you can override parameters from the LXC container configuration
	// file via ["--define", "KEY=VALUE"]. Defaults to []. See
	// man 1 lxc-start for available options.
	StartOptions []string `mapstructure:"start_options" required:"false"`
	// Options to pass to lxc-attach. For
	// instance, you can prevent the container from inheriting the host machine's
	// environment by specifying ["--clear-env"]. Defaults to []. See
	// man 1 lxc-attach for available options.
	AttachOptions []string `mapstructure:"attach_options" required:"false"`
	// The LXC template name to use.
	Name string `mapstructure:"template_name" required:"true"`
	// Options to pass to the given
	// lxc-template command, usually located in
	// /usr/share/lxc/templates/lxc-<template_name>. Note: This gets passed as
	// ARGV to the template command. Ensure you have an array of strings, as a
	// single string with spaces probably won't work. Defaults to [].
	Parameters []string `mapstructure:"template_parameters" required:"false"`
	// Environmental variables to
	// use to build the template with.
	EnvVars []string `mapstructure:"template_environment_vars" required:"true"`
	// The minimum run level to wait for the
	// container to reach. Note some distributions (Ubuntu) simulate run levels
	// and may report 5 rather than 3.
	TargetRunlevel int `mapstructure:"target_runlevel" required:"false"`

	ctx interpolate.Context
}

func (c *Config) Prepare(raws ...interface{}) error {

	var md mapstructure.Metadata
	err := config.Decode(c, &config.DecodeOpts{
		Metadata:    &md,
		Interpolate: true,
	}, raws...)
	if err != nil {
		return err
	}

	// Accumulate any errors
	var errs *packer.MultiError

	if c.OutputDir == "" {
		c.OutputDir = fmt.Sprintf("output-%s", c.PackerBuildName)
	}

	if c.ContainerName == "" {
		c.ContainerName = fmt.Sprintf("packer-%s", c.PackerBuildName)
	}

	if c.TargetRunlevel == 0 {
		c.TargetRunlevel = 3
	}

	if c.CommandWrapper == "" {
		c.CommandWrapper = "{{.Command}}"
	}

	if c.InitTimeout == 0 {
		c.InitTimeout = 20 * time.Second
	}

	if _, err := os.Stat(c.ConfigFile); os.IsNotExist(err) {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("LXC Config file appears to be missing: %s", c.ConfigFile))
	}

	if errs != nil && len(errs.Errors) > 0 {
		return errs
	}

	return nil
}