package config

import (
	"errors"
	"fmt"
	"os"
	"strings"
)

// DispatcherRuntimeEnvironment contains deployment-owned runtime settings. A
// pure preflight must finish before any SQLite, MQ, HTTP or gRPC resource opens.
type DispatcherRuntimeEnvironment struct {
	DispatcherEnvironment
	Listen             string
	AgentEndpointsFile string
	OSSConfigFile      string
	CAFile             string
	CertFile           string
	KeyFile            string
	PeerFingerprints   map[string]struct{}
}

func LoadDispatcherRuntimeEnvironment(mode string) (DispatcherRuntimeEnvironment, error) {
	base, err := LoadDispatcherEnvironment(mode)
	if err != nil {
		return DispatcherRuntimeEnvironment{}, err
	}
	settings := DispatcherRuntimeEnvironment{DispatcherEnvironment: base}
	get := func(name string) (string, error) {
		value := os.Getenv(name)
		if strings.TrimSpace(value) == "" {
			return "", fmt.Errorf("%s is required", name)
		}
		return value, nil
	}
	for _, field := range []struct {
		name  string
		value *string
	}{
		{"DISPATCHER_AGENT_ENDPOINTS_FILE", &settings.AgentEndpointsFile},
		{"MTLS_CA_FILE", &settings.CAFile},
		{"MTLS_CERT_FILE", &settings.CertFile},
		{"MTLS_KEY_FILE", &settings.KeyFile},
	} {
		value, err := get(field.name)
		if err != nil {
			return DispatcherRuntimeEnvironment{}, err
		}
		*field.value = value
	}
	if mode == "sip-only" {
		return settings, nil
	}
	if settings.Listen, err = get("DISPATCHER_GRPC_LISTEN"); err != nil {
		return DispatcherRuntimeEnvironment{}, err
	}
	if settings.OSSConfigFile, err = get("DISPATCHER_OSS_CONFIG_FILE"); err != nil {
		return DispatcherRuntimeEnvironment{}, err
	}
	if !localGRPCAddress(settings.Listen, true) {
		return DispatcherRuntimeEnvironment{}, errors.New("DISPATCHER_GRPC_LISTEN must be an isolated local Mock address")
	}
	fingerprints, err := get("MTLS_PEER_CERT_FINGERPRINTS")
	if err != nil {
		return DispatcherRuntimeEnvironment{}, err
	}
	settings.PeerFingerprints, err = ParseCertificateFingerprints(fingerprints)
	if err != nil || len(settings.PeerFingerprints) == 0 {
		return DispatcherRuntimeEnvironment{}, errors.New("MTLS_PEER_CERT_FINGERPRINTS is invalid")
	}
	return settings, nil
}