package config

import (
	"fmt"
	"regexp"
	"strings"
)

// StaticKind is the kind of hosts defined under hosts: instead of NetBox.
const StaticKind = "static"

// StaticHost is a host that is not in NetBox, defined in the config.
type StaticHost struct {
	Name    string     `mapstructure:"name"`
	Address string     `mapstructure:"address"` // IP address or DNS name
	User    string     `mapstructure:"user"`
	Port    int        `mapstructure:"port"`
	Tags    []string   `mapstructure:"tags"`
	SSH     SSHOptions `mapstructure:"ssh"`
}

var staticHostName = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._-]*$`)

// ValidateHosts keeps static host names usable as selectors and addresses
// safe to pass to ssh.
func (c *Config) ValidateHosts() error {
	seen := make(map[string]bool)
	for i, host := range c.Hosts {
		scope := fmt.Sprintf("hosts[%d]", i)
		if !staticHostName.MatchString(host.Name) {
			return fmt.Errorf("%s: name %q must start with a letter or digit and contain only letters, digits, dots, underscores, or hyphens", scope, host.Name)
		}
		name := strings.ToLower(host.Name)
		if seen[name] {
			return fmt.Errorf("%s: duplicate host name %q", scope, host.Name)
		}
		seen[name] = true
		if host.Address == "" || strings.HasPrefix(host.Address, "-") || strings.ContainsAny(host.Address, " \t\n\r/@") {
			return fmt.Errorf("%s: address %q must be an IP address or hostname", scope, host.Address)
		}
		if host.Port < 0 || host.Port > 65535 {
			return fmt.Errorf("%s: port must be between 1 and 65535", scope)
		}
		if strings.HasPrefix(host.User, "-") || strings.ContainsAny(host.User, " \t\n\r@") {
			return fmt.Errorf("%s: invalid user %q", scope, host.User)
		}
		if err := host.SSH.Validate(scope + ".ssh"); err != nil {
			return err
		}
	}
	return nil
}

// StaticHost returns the static host with the given name, or nil.
func (c *Config) StaticHost(name string) *StaticHost {
	for i := range c.Hosts {
		if strings.EqualFold(c.Hosts[i].Name, name) {
			return &c.Hosts[i]
		}
	}
	return nil
}