//go:generate struct-markdown
//go:generate mapstructure-to-hcl2 -type AmiFilterOptions,SecurityGroupFilterOptions,SubnetFilterOptions,VpcFilterOptions,PolicyDocument,Statement

package common

import (
	"fmt"
	"net"
	"os"
	"regexp"
	"strings"
	"time"

	"github.com/hashicorp/packer/common/uuid"
	"github.com/hashicorp/packer/hcl2template"
	"github.com/hashicorp/packer/helper/communicator"
	"github.com/hashicorp/packer/template/interpolate"
)

var reShutdownBehavior = regexp.MustCompile("^(stop|terminate)$")

type AmiFilterOptions struct {
	hcl2template.KVFilter `mapstructure:",squash"`
	Owners                []string
	MostRecent            bool `mapstructure:"most_recent"`
}

func (d *AmiFilterOptions) GetOwners() []*string {
	res := make([]*string, 0, len(d.Owners))
	for _, owner := range d.Owners {
		i := owner
		res = append(res, &i)
	}
	return res
}

func (d *AmiFilterOptions) Empty() bool {
	return len(d.Owners) == 0 && d.KVFilter.Empty()
}

func (d *AmiFilterOptions) NoOwner() bool {
	return len(d.Owners) == 0
}

type SubnetFilterOptions struct {
	hcl2template.KVFilter `mapstructure:",squash"`
	MostFree              bool `mapstructure:"most_free"`
	Random                bool `mapstructure:"random"`
}

type VpcFilterOptions struct {
	hcl2template.KVFilter `mapstructure:",squash"`
}

type Statement struct {
	Effect   string
	Action   []string
	Resource string
}

type PolicyDocument struct {
	Version   string
	Statement []Statement
}

type SecurityGroupFilterOptions struct {
	hcl2template.KVFilter `mapstructure:",squash"`
}

// RunConfig contains configuration for running an instance from a source
// AMI and details on how to access that launched image.
type RunConfig struct {
	// If using a non-default VPC,
	// public IP addresses are not provided by default. If this is true, your
	// new instance will get a Public IP. default: false
	AssociatePublicIpAddress bool `mapstructure:"associate_public_ip_address" required:"false"`
	// Destination availability zone to launch
	// instance in. Leave this empty to allow Amazon to auto-assign.
	AvailabilityZone string `mapstructure:"availability_zone" required:"false"`
	// Requires spot_price to be set. The
	// required duration for the Spot Instances (also known as Spot blocks). This
	// value must be a multiple of 60 (60, 120, 180, 240, 300, or 360). You can't
	// specify an Availability Zone group or a launch group if you specify a
	// duration.
	BlockDurationMinutes int64 `mapstructure:"block_duration_minutes" required:"false"`
	// Packer normally stops the build instance after all provisioners have
	// run. For Windows instances, it is sometimes desirable to [run
	// Sysprep](http://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/ami-create-standard.html)
	// which will stop the instance for you. If this is set to `true`, Packer
	// *will not* stop the instance but will assume that you will send the stop
	// signal yourself through your final provisioner. You can do this with a
	// [windows-shell
	// provisioner](https://www.packer.io/docs/provisioners/windows-shell.html).
	// Note that Packer will still wait for the instance to be stopped, and
	// failing to send the stop signal yourself, when you have set this flag to
	// `true`, will cause a timeout.
	// Example of a valid shutdown command:
	//
	// ```json
	// {
	//   "type": "windows-shell",
	//   "inline": ["\"c:\\Program Files\\Amazon\\Ec2ConfigService\\ec2config.exe\" -sysprep"]
	// }
	// ```
	DisableStopInstance bool `mapstructure:"disable_stop_instance" required:"false"`
	// Mark instance as [EBS
	// Optimized](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSOptimized.html).
	// Default `false`.
	EbsOptimized bool `mapstructure:"ebs_optimized" required:"false"`
	// Enabling T2 Unlimited allows the source instance to burst additional CPU
	// beyond its available [CPU
	// Credits](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/t2-credits-baseline-concepts.html)
	// for as long as the demand exists. This is in contrast to the standard
	// configuration that only allows an instance to consume up to its
	// available CPU Credits. See the AWS documentation for [T2
	// Unlimited](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/t2-unlimited.html)
	// and the **T2 Unlimited Pricing** section of the [Amazon EC2 On-Demand
	// Pricing](https://aws.amazon.com/ec2/pricing/on-demand/) document for
	// more information. By default this option is disabled and Packer will set
	// up a [T2
	// Standard](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/t2-std.html)
	// instance instead.
	//
	// To use T2 Unlimited you must use a T2 instance type, e.g. `t2.micro`.
	// Additionally, T2 Unlimited cannot be used in conjunction with Spot
	// Instances, e.g. when the `spot_price` option has been configured.
	// Attempting to do so will cause an error.
	//
	// !> **Warning!** Additional costs may be incurred by enabling T2
	// Unlimited - even for instances that would usually qualify for the
	// [AWS Free Tier](https://aws.amazon.com/free/).
	EnableT2Unlimited bool `mapstructure:"enable_t2_unlimited" required:"false"`
	// The name of an [IAM instance
	// profile](https://docs.aws.amazon.com/IAM/latest/UserGuide/instance-profiles.html)
	// to launch the EC2 instance with.
	IamInstanceProfile string `mapstructure:"iam_instance_profile" required:"false"`
	// Whether or not to check if the IAM instance profile exists. Defaults to false
	SkipProfileValidation bool `mapstructure:"skip_profile_validation" required:"false"`
	// Temporary IAM instance profile policy document
	// If IamInstanceProfile is specified it will be used instead. Example:
	//
	// ```json
	//{
	//	"Version": "2012-10-17",
	//	"Statement": [
	//		{
	//			"Action": [
	//			"logs:*"
	//			],
	//			"Effect": "Allow",
	//			"Resource": "*"
	//		}
	//	]
	//}
	// ```
	//
	TemporaryIamInstanceProfilePolicyDocument *PolicyDocument `mapstructure:"temporary_iam_instance_profile_policy_document" required:"false"`
	// Automatically terminate instances on
	// shutdown in case Packer exits ungracefully. Possible values are stop and
	// terminate. Defaults to stop.
	InstanceInitiatedShutdownBehavior string `mapstructure:"shutdown_behavior" required:"false"`
	// The EC2 instance type to use while building the
	// AMI, such as t2.small.
	InstanceType string `mapstructure:"instance_type" required:"true"`
	// Filters used to populate the `security_group_ids` field. Example:
	//
	// ```json
	// {
	//   "security_group_filter": {
	//     "filters": {
	//       "tag:Class": "packer"
	//     }
	//   }
	// }
	// ```
	//
	// This selects the SG's with tag `Class` with the value `packer`.
	//
	// -   `filters` (map of strings) - filters used to select a
	//     `security_group_ids`. Any filter described in the docs for
	//     [DescribeSecurityGroups](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeSecurityGroups.html)
	//     is valid.
	//
	// `security_group_ids` take precedence over this.
	SecurityGroupFilter SecurityGroupFilterOptions `mapstructure:"security_group_filter" required:"false"`
	// Tags to apply to the instance that is that is *launched* to create the
	// EBS volumes. This is a [template engine](/docs/templates/engine.html),
	// see [Build template data](#build-template-data) for more information.
	RunTags map[string]string `mapstructure:"run_tags" required:"false"`
	// Same as [`run_tags`](#run_tags) but defined as a singular repeatable
	// block containing a key and a value field. In HCL2 mode the
	// [`dynamic_block`](https://packer.io/docs/configuration/from-1.5/expressions.html#dynamic-blocks)
	// will allow you to create those programatically.
	RunTag hcl2template.KeyValues `mapstructure:"run_tag" required:"false"`
	// The ID (not the name) of the security
	// group to assign to the instance. By default this is not set and Packer will
	// automatically create a new temporary security group to allow SSH access.
	// Note that if this is specified, you must be sure the security group allows
	// access to the ssh_port given below.
	SecurityGroupId string `mapstructure:"security_group_id" required:"false"`
	// A list of security groups as
	// described above. Note that if this is specified, you must omit the
	// security_group_id.
	SecurityGroupIds []string `mapstructure:"security_group_ids" required:"false"`
	// The source AMI whose root volume will be copied and
	// provisioned on the currently running instance. This must be an EBS-backed
	// AMI with a root volume snapshot that you have access to. Note: this is not
	// used when from_scratch is set to true.
	SourceAmi string `mapstructure:"source_ami" required:"true"`
	// Filters used to populate the `source_ami`
	// field. Example:
	//
	//   ```json
	//   {
	//     "source_ami_filter": {
	//       "filters": {
	//         "virtualization-type": "hvm",
	//         "name": "ubuntu/images/\*ubuntu-xenial-16.04-amd64-server-\*",
	//         "root-device-type": "ebs"
	//       },
	//       "owners": ["099720109477"],
	//       "most_recent": true
	//     }
	//   }
	//   ```
	//
	//   This selects the most recent Ubuntu 16.04 HVM EBS AMI from Canonical. NOTE:
	//   This will fail unless *exactly* one AMI is returned. In the above example,
	//   `most_recent` will cause this to succeed by selecting the newest image.
	//
	//   -   `filters` (map of strings) - filters used to select a `source_ami`.
	//       NOTE: This will fail unless *exactly* one AMI is returned. Any filter
	//       described in the docs for
	//       [DescribeImages](http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeImages.html)
	//       is valid.
	//
	//   -   `owners` (array of strings) - Filters the images by their owner. You
	//       may specify one or more AWS account IDs, "self" (which will use the
	//       account whose credentials you are using to run Packer), or an AWS owner
	//       alias: for example, `amazon`, `aws-marketplace`, or `microsoft`. This
	//       option is required for security reasons.
	//
	//   -   `most_recent` (boolean) - Selects the newest created image when true.
	//       This is most useful for selecting a daily distro build.
	//
	//   You may set this in place of `source_ami` or in conjunction with it. If you
	//   set this in conjunction with `source_ami`, the `source_ami` will be added
	//   to the filter. The provided `source_ami` must meet all of the filtering
	//   criteria provided in `source_ami_filter`; this pins the AMI returned by the
	//   filter, but will cause Packer to fail if the `source_ami` does not exist.
	SourceAmiFilter AmiFilterOptions `mapstructure:"source_ami_filter" required:"false"`
	// a list of acceptable instance
	// types to run your build on. We will request a spot instance using the max
	// price of spot_price and the allocation strategy of "lowest price".
	// Your instance will be launched on an instance type of the lowest available
	// price that you have in your list.  This is used in place of instance_type.
	// You may only set either spot_instance_types or instance_type, not both.
	// This feature exists to help prevent situations where a Packer build fails
	// because a particular availability zone does not have capacity for the
	// specific instance_type requested in instance_type.
	SpotInstanceTypes []string `mapstructure:"spot_instance_types" required:"false"`
	// With Spot Instances, you pay the Spot price that's in effect for the
	// time period your instances are running. Spot Instance prices are set by
	// Amazon EC2 and adjust gradually based on long-term trends in supply and
	// demand for Spot Instance capacity.
	//
	// When this field is set, it represents the maximum hourly price you are
	// willing to pay for a spot instance. If you do not set this value, it
	// defaults to a maximum price equal to the on demand price of the
	// instance. In the situation where the current Amazon-set spot price
	// exceeds the value set in this field, Packer will not launch an instance
	// and the build will error. In the situation where the Amazon-set spot
	// price is less than the value set in this field, Packer will launch and
	// you will pay the Amazon-set spot price, not this maximum value.
	// For more information, see the Amazon docs on
	// [spot pricing](https://aws.amazon.com/ec2/spot/pricing/).
	SpotPrice string `mapstructure:"spot_price" required:"false"`
	// Required if spot_price is set to
	// auto. This tells Packer what sort of AMI you're launching to find the
	// best spot price. This must be one of: Linux/UNIX, SUSE Linux,
	// Windows, Linux/UNIX (Amazon VPC), SUSE Linux (Amazon VPC),
	// Windows (Amazon VPC)
	SpotPriceAutoProduct string `mapstructure:"spot_price_auto_product" required:"false"`
	// Requires spot_price to be set. This tells Packer to apply tags to the
	// spot request that is issued.
	SpotTags map[string]string `mapstructure:"spot_tags" required:"false"`
	// Same as [`spot_tags`](#spot_tags) but defined as a singular repeatable block
	// containing a key and a value field. In HCL2 mode the
	// [`dynamic_block`](https://packer.io/docs/configuration/from-1.5/expressions.html#dynamic-blocks)
	// will allow you to create those programatically.
	SpotTag hcl2template.KeyValues `mapstructure:"spot_tag" required:"false"`
	// Filters used to populate the `subnet_id` field.
	// Example:
	//
	//   ```json
	//   {
	//     "subnet_filter": {
	//       "filters": {
	//         "tag:Class": "build"
	//       },
	//       "most_free": true,
	//       "random": false
	//     }
	//   }
	//   ```
	//
	//   This selects the Subnet with tag `Class` with the value `build`, which has
	//   the most free IP addresses. NOTE: This will fail unless *exactly* one
	//   Subnet is returned. By using `most_free` or `random` one will be selected
	//   from those matching the filter.
	//
	//   -   `filters` (map of strings) - filters used to select a `subnet_id`.
	//       NOTE: This will fail unless *exactly* one Subnet is returned. Any
	//       filter described in the docs for
	//       [DescribeSubnets](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeSubnets.html)
	//       is valid.
	//
	//   -   `most_free` (boolean) - The Subnet with the most free IPv4 addresses
	//       will be used if multiple Subnets matches the filter.
	//
	//   -   `random` (boolean) - A random Subnet will be used if multiple Subnets
	//       matches the filter. `most_free` have precendence over this.
	//
	//   `subnet_id` take precedence over this.
	SubnetFilter SubnetFilterOptions `mapstructure:"subnet_filter" required:"false"`
	// If using VPC, the ID of the subnet, such as
	// subnet-12345def, where Packer will launch the EC2 instance. This field is
	// required if you are using an non-default VPC.
	SubnetId string `mapstructure:"subnet_id" required:"false"`
	// The name of the temporary key pair to
	// generate. By default, Packer generates a name that looks like
	// `packer_<UUID>`, where &lt;UUID&gt; is a 36 character unique identifier.
	TemporaryKeyPairName string `mapstructure:"temporary_key_pair_name" required:"false"`
	// A list of IPv4 CIDR blocks to be authorized access to the instance, when
	// packer is creating a temporary security group.
	//
	// The default is [`0.0.0.0/0`] (i.e., allow any IPv4 source). This is only
	// used when `security_group_id` or `security_group_ids` is not specified.
	TemporarySGSourceCidrs []string `mapstructure:"temporary_security_group_source_cidrs" required:"false"`
	// User data to apply when launching the instance. Note
	// that you need to be careful about escaping characters due to the templates
	// being JSON. It is often more convenient to use user_data_file, instead.
	// Packer will not automatically wait for a user script to finish before
	// shutting down the instance this must be handled in a provisioner.
	UserData string `mapstructure:"user_data" required:"false"`
	// Path to a file that will be used for the user
	// data when launching the instance.
	UserDataFile string `mapstructure:"user_data_file" required:"false"`
	// Filters used to populate the `vpc_id` field.
	// Example:
	//
	// ```json
	// {
	//   "vpc_filter": {
	//     "filters": {
	//       "tag:Class": "build",
	//       "isDefault": "false",
	//       "cidr": "/24"
	//     }
	//   }
	// }
	// ```
	//
	// This selects the VPC with tag `Class` with the value `build`, which is not
	// the default VPC, and have a IPv4 CIDR block of `/24`. NOTE: This will fail
	// unless *exactly* one VPC is returned.
	//
	// -   `filters` (map of strings) - filters used to select a `vpc_id`. NOTE:
	//     This will fail unless *exactly* one VPC is returned. Any filter
	//     described in the docs for
	//     [DescribeVpcs](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeVpcs.html)
	//     is valid.
	//
	// `vpc_id` take precedence over this.
	VpcFilter VpcFilterOptions `mapstructure:"vpc_filter" required:"false"`
	// If launching into a VPC subnet, Packer needs the VPC ID
	// in order to create a temporary security group within the VPC. Requires
	// subnet_id to be set. If this field is left blank, Packer will try to get
	// the VPC ID from the subnet_id.
	VpcId string `mapstructure:"vpc_id" required:"false"`
	// The timeout for waiting for a Windows
	// password for Windows instances. Defaults to 20 minutes. Example value:
	// 10m
	WindowsPasswordTimeout time.Duration `mapstructure:"windows_password_timeout" required:"false"`

	// Communicator settings
	Comm communicator.Config `mapstructure:",squash"`

	// One of `public_ip`, `private_ip`, `public_dns`, or `private_dns`. If
	//    set, either the public IP address, private IP address, public DNS name
	//    or private DNS name will be used as the host for SSH. The default behaviour
	//    if inside a VPC is to use the public IP address if available, otherwise
	//    the private IP address will be used. If not in a VPC the public DNS name
	//    will be used. Also works for WinRM.
	//
	//    Where Packer is configured for an outbound proxy but WinRM traffic
	//    should be direct, `ssh_interface` must be set to `private_dns` and
	//    `<region>.compute.internal` included in the `NO_PROXY` environment
	//    variable.
	SSHInterface string `mapstructure:"ssh_interface"`
}

func (c *RunConfig) Prepare(ctx *interpolate.Context) []error {
	// If we are not given an explicit ssh_keypair_name or
	// ssh_private_key_file, then create a temporary one, but only if the
	// temporary_key_pair_name has not been provided and we are not using
	// ssh_password.
	if c.Comm.SSHKeyPairName == "" && c.Comm.SSHTemporaryKeyPairName == "" &&
		c.Comm.SSHPrivateKeyFile == "" && c.Comm.SSHPassword == "" {

		c.Comm.SSHTemporaryKeyPairName = fmt.Sprintf("packer_%s", uuid.TimeOrderedUUID())
	}

	if c.WindowsPasswordTimeout == 0 {
		c.WindowsPasswordTimeout = 20 * time.Minute
	}

	if c.RunTags == nil {
		c.RunTags = make(map[string]string)
	}

	// Validation
	errs := c.Comm.Prepare(ctx)

	// Copy singular tag maps
	errs = append(errs, c.RunTag.CopyOn(&c.RunTags)...)
	errs = append(errs, c.SpotTag.CopyOn(&c.SpotTags)...)

	for _, preparer := range []interface{ Prepare() []error }{
		&c.SourceAmiFilter,
		&c.SecurityGroupFilter,
		&c.SubnetFilter,
		&c.VpcFilter,
	} {
		errs = append(errs, preparer.Prepare()...)
	}

	// Validating ssh_interface
	if c.SSHInterface != "public_ip" &&
		c.SSHInterface != "private_ip" &&
		c.SSHInterface != "public_dns" &&
		c.SSHInterface != "private_dns" &&
		c.SSHInterface != "" {
		errs = append(errs, fmt.Errorf("Unknown interface type: %s", c.SSHInterface))
	}

	if c.Comm.SSHKeyPairName != "" {
		if c.Comm.Type == "winrm" && c.Comm.WinRMPassword == "" && c.Comm.SSHPrivateKeyFile == "" {
			errs = append(errs, fmt.Errorf("ssh_private_key_file must be provided to retrieve the winrm password when using ssh_keypair_name."))
		} else if c.Comm.SSHPrivateKeyFile == "" && !c.Comm.SSHAgentAuth {
			errs = append(errs, fmt.Errorf("ssh_private_key_file must be provided or ssh_agent_auth enabled when ssh_keypair_name is specified."))
		}
	}

	if c.SourceAmi == "" && c.SourceAmiFilter.Empty() {
		errs = append(errs, fmt.Errorf("A source_ami or source_ami_filter must be specified"))
	}

	if c.SourceAmi == "" && c.SourceAmiFilter.NoOwner() {
		errs = append(errs, fmt.Errorf("For security reasons, your source AMI filter must declare an owner."))
	}

	if c.InstanceType == "" && len(c.SpotInstanceTypes) == 0 {
		errs = append(errs, fmt.Errorf("either instance_type or "+
			"spot_instance_types must be specified"))
	}

	if c.InstanceType != "" && len(c.SpotInstanceTypes) > 0 {
		errs = append(errs, fmt.Errorf("either instance_type or "+
			"spot_instance_types must be specified, not both"))
	}

	if c.BlockDurationMinutes%60 != 0 {
		errs = append(errs, fmt.Errorf(
			"block_duration_minutes must be multiple of 60"))
	}

	if c.SpotTags != nil {
		if c.SpotPrice == "" || c.SpotPrice == "0" {
			errs = append(errs, fmt.Errorf(
				"spot_tags should not be set when not requesting a spot instance"))
		}
	}

	if c.UserData != "" && c.UserDataFile != "" {
		errs = append(errs, fmt.Errorf("Only one of user_data or user_data_file can be specified."))
	} else if c.UserDataFile != "" {
		if _, err := os.Stat(c.UserDataFile); err != nil {
			errs = append(errs, fmt.Errorf("user_data_file not found: %s", c.UserDataFile))
		}
	}

	if c.SecurityGroupId != "" {
		if len(c.SecurityGroupIds) > 0 {
			errs = append(errs, fmt.Errorf("Only one of security_group_id or security_group_ids can be specified."))
		} else {
			c.SecurityGroupIds = []string{c.SecurityGroupId}
			c.SecurityGroupId = ""
		}
	}

	if len(c.TemporarySGSourceCidrs) == 0 {
		c.TemporarySGSourceCidrs = []string{"0.0.0.0/0"}
	} else {
		for _, cidr := range c.TemporarySGSourceCidrs {
			if _, _, err := net.ParseCIDR(cidr); err != nil {
				errs = append(errs, fmt.Errorf("Error parsing CIDR in temporary_security_group_source_cidrs: %s", err.Error()))
			}
		}
	}

	if c.InstanceInitiatedShutdownBehavior == "" {
		c.InstanceInitiatedShutdownBehavior = "stop"
	} else if !reShutdownBehavior.MatchString(c.InstanceInitiatedShutdownBehavior) {
		errs = append(errs, fmt.Errorf("shutdown_behavior only accepts 'stop' or 'terminate' values."))
	}

	if c.EnableT2Unlimited {
		if c.SpotPrice != "" {
			errs = append(errs, fmt.Errorf("Error: T2 Unlimited cannot be used in conjuction with Spot Instances"))
		}
		firstDotIndex := strings.Index(c.InstanceType, ".")
		if firstDotIndex == -1 {
			errs = append(errs, fmt.Errorf("Error determining main Instance Type from: %s", c.InstanceType))
		} else if c.InstanceType[0:firstDotIndex] != "t2" {
			errs = append(errs, fmt.Errorf("Error: T2 Unlimited enabled with a non-T2 Instance Type: %s", c.InstanceType))
		}
	}

	return errs
}

func (c *RunConfig) IsSpotInstance() bool {
	return c.SpotPrice != "" && c.SpotPrice != "0"
}