package config

import (
	"net/http"
	"path/filepath"

	"github.com/docker/docker/client"
	"github.com/docker/go-connections/tlsconfig"
)

var Default Config

type Config struct {
	Debug         bool         `mapstructure:"debug"`
	PluginAPIPort int          `mapstructure:"plugin_api_port" validate:"gte=0,lte=65535"`
	Docker        DockerConfig `mapstructure:"docker"`
	DefaultServer string       `mapstructure:"default_server"`
	Servers       []Server     `mapstructure:"servers"`
}

type DockerConfig struct {
	FromEnv   *bool  `mapstructure:"from_env,omitempty"`
	CertPath  string `mapstructure:"cert_path"`
	TLSVerify *bool  `mapstructure:"tls_verify,omitempty"`
	Host      string `mapstructure:"host"`
	Version   string `mapstructure:"version"`
}

type DriverParams map[string]interface{}

type DriverType string

const (
	DriverSSH    DriverType = "ssh"
	DriverPlugin DriverType = "plugin"
	DriverNull   DriverType = "null"
)

type Server struct {
	Name   string       `mapstructure:"name" validate:"required"`
	Driver DriverType   `mapstructure:"driver"`
	Params DriverParams `mapstructure:"params"`
}

func (d DockerConfig) Opts(c *client.Client) error {
	if d.FromEnv == nil || *d.FromEnv {
		return client.FromEnv(c)
	}
	ops := []client.Opt{
		d.withTLSClientConfig(),
		d.withHost(),
		d.withVersion(),
	}
	for _, op := range ops {
		if err := op(c); err != nil {
			return err
		}
	}
	return nil
}

func (d DockerConfig) withTLSClientConfig() client.Opt {
	return func(c *client.Client) error {
		dockerCertPath := d.CertPath
		if dockerCertPath == "" {
			return nil
		}
		skipTLSVerify := false
		if d.TLSVerify != nil && !(*d.TLSVerify) {
			skipTLSVerify = true
		}
		options := tlsconfig.Options{
			CAFile:             filepath.Join(dockerCertPath, "ca.pem"),
			CertFile:           filepath.Join(dockerCertPath, "cert.pem"),
			KeyFile:            filepath.Join(dockerCertPath, "key.pem"),
			InsecureSkipVerify: skipTLSVerify,
		}
		tlsConfig, err := tlsconfig.Client(options)
		if err != nil {
			return err
		}

		return client.WithHTTPClient(&http.Client{
			Transport:     &http.Transport{TLSClientConfig: tlsConfig},
			CheckRedirect: client.CheckRedirect,
		})(c)
	}
}

func (d DockerConfig) withHost() client.Opt {
	return func(c *client.Client) error {
		if host := d.Host; host != "" {
			return client.WithHost(host)(c)
		}
		return nil
	}
}

func (d DockerConfig) withVersion() client.Opt {
	return func(c *client.Client) error {
		return client.WithVersion(d.Version)(c)
	}
}