package common

import (
	"errors"
	"fmt"
	"github.com/mitchellh/packer/packer"
	"os"
	"time"
)

// RunConfig contains configuration for running an instance from a source
// AMI and details on how to access that launched image.
type RunConfig struct {
	SourceAmi          string `mapstructure:"source_ami"`
	IamInstanceProfile string `mapstructure:"iam_instance_profile"`
	InstanceType       string `mapstructure:"instance_type"`
	UserData           string `mapstructure:"user_data"`
	UserDataFile       string `mapstructure:"user_data_file"`
	RawSSHTimeout      string `mapstructure:"ssh_timeout"`
	SSHUsername        string `mapstructure:"ssh_username"`
	SSHPort            int    `mapstructure:"ssh_port"`
	SecurityGroupId    string `mapstructure:"security_group_id"`
	SubnetId           string `mapstructure:"subnet_id"`
	VpcId              string `mapstructure:"vpc_id"`
	SSHKeyPairPattern  string `mapstructure:"ssh_keypair_pattern"`

	// Unexported fields that are calculated from others
	sshTimeout time.Duration
}

func (c *RunConfig) Prepare(t *packer.ConfigTemplate) []error {
	if t == nil {
		var err error
		t, err = packer.NewConfigTemplate()
		if err != nil {
			return []error{err}
		}
	}

	// Defaults
	if c.SSHPort == 0 {
		c.SSHPort = 22
	}

	if c.RawSSHTimeout == "" {
		c.RawSSHTimeout = "1m"
	}

	if c.SSHKeyPairPattern == "" {
		c.SSHKeyPairPattern = "packer %s"
	}

	// Validation
	var err error
	errs := make([]error, 0)
	if c.SourceAmi == "" {
		errs = append(errs, errors.New("A source_ami must be specified"))
	}

	if c.InstanceType == "" {
		errs = append(errs, errors.New("An instance_type must be specified"))
	}

	if c.SSHUsername == "" {
		errs = append(errs, errors.New("An ssh_username must be specified"))
	}

	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))
		}
	}

	templates := map[string]*string{
		"iam_instance_profile": &c.IamInstanceProfile,
		"instance_type":        &c.InstanceType,
		"ssh_timeout":          &c.RawSSHTimeout,
		"security_group_id":    &c.SecurityGroupId,
		"ssh_username":         &c.SSHUsername,
		"source_ami":           &c.SourceAmi,
		"subnet_id":            &c.SubnetId,
		"vpc_id":               &c.VpcId,
	}

	for n, ptr := range templates {
		var err error
		*ptr, err = t.Process(*ptr, nil)
		if err != nil {
			errs = append(
				errs, fmt.Errorf("Error processing %s: %s", n, err))
		}
	}

	c.sshTimeout, err = time.ParseDuration(c.RawSSHTimeout)
	if err != nil {
		errs = append(errs, fmt.Errorf("Failed parsing ssh_timeout: %s", err))
	}

	return errs
}

func (c *RunConfig) SSHTimeout() time.Duration {
	return c.sshTimeout
}