package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/BurntSushi/toml"
	"github.com/csaf-poc/csaf_distribution/csaf"
)

const (
	configEnv         = "CSAF_CONFIG"
	defaultConfigPath = "/usr/lib/casf/config.toml"
	defaultFolder     = "/var/www/"
	defaultWeb        = "/var/www/html"
	defaultPGPURL     = "http://pgp.mit.edu/pks/lookup?search=${KEY}&op=index"
)

type config struct {
	Key             string          `toml:"key"`
	Folder          string          `toml:"folder"`
	Web             string          `toml:"web"`
	TLPs            []tlp           `toml:"tlps"`
	UploadSignature bool            `toml:"upload_signature"`
	PGPURL          string          `toml:"pgp_url"`
	Domain          string          `toml:"domain"`
	NoPassphrase    bool            `toml:"no_passphrase"`
	Publisher       *csaf.Publisher `toml:"publisher"`
}

type tlp string

const (
	tlpCSAF  tlp = "csaf"
	tlpWhite tlp = "white"
	tlpGreen tlp = "green"
	tlpAmber tlp = "amber"
	tlpRed   tlp = "red"
)

func (t tlp) valid() bool {
	switch t {
	case tlpCSAF, tlpWhite, tlpGreen, tlpAmber, tlpRed:
		return true
	default:
		return false
	}
}

func (t *tlp) UnmarshalText(text []byte) error {
	if s := tlp(text); s.valid() {
		*t = s
		return nil
	}
	return fmt.Errorf("invalid config TLP value: %v", string(text))
}

func (cfg *config) GetPGPURL(key string) string {
	return strings.ReplaceAll(cfg.PGPURL, "${KEY}", key)
}

func (cfg *config) modelTLPs() []csaf.TLPLabel {
	tlps := make([]csaf.TLPLabel, len(cfg.TLPs))
	for _, t := range cfg.TLPs {
		if t != tlpCSAF {
			tlps = append(tlps, csaf.TLPLabel(t))
		}
	}
	return tlps
}

func loadConfig() (*config, error) {
	path := os.Getenv(configEnv)
	if path == "" {
		path = defaultConfigPath
	}
	var cfg config
	if _, err := toml.DecodeFile(path, &cfg); err != nil {
		return nil, err
	}

	// Preset defaults

	if cfg.Folder == "" {
		cfg.Folder = defaultFolder
	}

	if cfg.Web == "" {
		cfg.Web = defaultWeb
	}

	if cfg.Domain == "" {
		cfg.Domain = "http://" + os.Getenv("SERVER_NAME")
	}

	if cfg.TLPs == nil {
		cfg.TLPs = []tlp{tlpCSAF, tlpWhite, tlpGreen, tlpAmber, tlpRed}
	}

	if cfg.PGPURL == "" {
		cfg.PGPURL = defaultPGPURL
	}

	return &cfg, nil
}