package inbucket

import (
	"container/list"
	"fmt"
	"github.com/robfig/goconfig/config"
	"net"
	"os"
)

// SmtpConfig houses the SMTP server configuration - not using pointers
// so that I can pass around copies of the object safely.
type SmtpConfig struct {
	Ip4address net.IP
	Ip4port    int
	Domain     string
}

type WebConfig struct {
	Ip4address    net.IP
	Ip4port       int
	TemplateDir   string
	TemplateCache bool
	PublicDir     string
}

var smtpConfig *SmtpConfig

var webConfig *WebConfig

var Config *config.Config

// GetSmtpConfig returns a copy of the SmtpConfig object
func GetSmtpConfig() SmtpConfig {
	return *smtpConfig
}

// GetWebConfig returns a copy of the WebConfig object
func GetWebConfig() WebConfig {
	return *webConfig
}

// LoadConfig loads the specified configuration file into inbucket.Config
// and performs validations on it.
func LoadConfig(filename string) error {
	var err error
	Config, err = config.ReadDefault(filename)
	if err != nil {
		return err
	}

	messages := list.New()

	// Validate sections
	requireSection(messages, "smtp")
	requireSection(messages, "web")
	requireSection(messages, "datastore")
	if messages.Len() > 0 {
		fmt.Fprintln(os.Stderr, "Error(s) validating configuration:")
		for e := messages.Front(); e != nil; e = e.Next() {
			fmt.Fprintln(os.Stderr, " -", e.Value.(string))
		}
		return fmt.Errorf("Failed to validate configuration")
	}

	// Validate options
	requireOption(messages, "smtp", "ip4.address")
	requireOption(messages, "smtp", "ip4.port")
	requireOption(messages, "smtp", "domain")
	requireOption(messages, "web", "ip4.address")
	requireOption(messages, "web", "ip4.port")
	requireOption(messages, "web", "template.dir")
	requireOption(messages, "web", "template.cache")
	requireOption(messages, "web", "public.dir")
	requireOption(messages, "datastore", "path")
	if messages.Len() > 0 {
		fmt.Fprintln(os.Stderr, "Error(s) validating configuration:")
		for e := messages.Front(); e != nil; e = e.Next() {
			fmt.Fprintln(os.Stderr, " -", e.Value.(string))
		}
		return fmt.Errorf("Failed to validate configuration")
	}

	err = parseSmtpConfig()
	if err != nil {
		return nil
	}

	err = parseWebConfig()

	return err
}

// parseSmtpConfig trying to catch config errors early
func parseSmtpConfig() error {
	smtpConfig = new(SmtpConfig)

	// Parse IP4 address only, error on IP6.
	option := "[smtp]ip4.address"
	str, err := Config.String("smtp", "ip4.address")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	addr := net.ParseIP(str)
	if addr == nil {
		return fmt.Errorf("Failed to parse %v '%v'", option, str)
	}
	addr = addr.To4()
	if addr == nil {
		return fmt.Errorf("Failed to parse %v '%v' not IPv4!", option, str)
	}
	smtpConfig.Ip4address = addr

	option = "[smtp]ip4.port"
	smtpConfig.Ip4port, err = Config.Int("smtp", "ip4.port")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}

	option = "[smtp]domain"
	str, err = Config.String("smtp", "domain")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	smtpConfig.Domain = str

	return nil
}

// parseWebConfig trying to catch config errors early
func parseWebConfig() error {
	webConfig = new(WebConfig)

	// Parse IP4 address only, error on IP6.
	option := "[web]ip4.address"
	str, err := Config.String("web", "ip4.address")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	addr := net.ParseIP(str)
	if addr == nil {
		return fmt.Errorf("Failed to parse %v '%v'", option, str)
	}
	addr = addr.To4()
	if addr == nil {
		return fmt.Errorf("Failed to parse %v '%v' not IPv4!", option, str)
	}
	webConfig.Ip4address = addr

	option = "[web]ip4.port"
	webConfig.Ip4port, err = Config.Int("web", "ip4.port")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}

	option = "[web]template.dir"
	str, err = Config.String("web", "template.dir")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	webConfig.TemplateDir = str

	option = "[web]template.cache"
	flag, err := Config.Bool("web", "template.cache")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	webConfig.TemplateCache = flag

	option = "[web]public.dir"
	str, err = Config.String("web", "public.dir")
	if err != nil {
		return fmt.Errorf("Failed to parse %v: %v", option, err)
	}
	webConfig.PublicDir = str

	return nil
}

// requireSection checks that a [section] is defined in the configuration file,
// appending a message if not.
func requireSection(messages *list.List, section string) {
	if !Config.HasSection(section) {
		messages.PushBack(fmt.Sprintf("Config section [%v] is required", section))
	}
}

// requireOption checks that 'option' is defined in [section] of the config file,
// appending a message if not.
func requireOption(messages *list.List, section string, option string) {
	if !Config.HasOption(section, option) {
		messages.PushBack(fmt.Sprintf("Config option '%v' is required in section [%v]", option, section))
	}
}