package authn

import (
	"reflect"
	"time"

	"forge.cadoles.com/cadoles/bouncer/internal/store"
	"github.com/mitchellh/mapstructure"
	"github.com/pkg/errors"
)

type LayerOptions struct {
	MatchURLs []string       `mapstructure:"matchURLs"`
	Headers   HeadersOptions `mapstructure:"headers"`
}

type HeadersOptions struct {
	Rules []string `mapstructure:"rules"`
}

func DefaultLayerOptions() LayerOptions {
	return LayerOptions{
		MatchURLs: []string{"*"},
		Headers: HeadersOptions{
			Rules: []string{
				"del_headers('Remote-*')",
				"set_header('Remote-User', user.subject)",
				`map(
					toPairs(user.attrs), {
						let name = replace(lower(string(get(#, 0))), '_', '-');
						set_header(
							'Remote-User-Attr-' + name, 
							get(#, 1)
						) 
					})
				`,
			},
		},
	}
}

func fromStoreOptions(storeOptions store.LayerOptions) (*LayerOptions, error) {
	layerOptions := DefaultLayerOptions()

	if err := FromStoreOptions(storeOptions, &layerOptions); err != nil {
		return nil, errors.WithStack(err)
	}

	return &layerOptions, nil
}

func FromStoreOptions(storeOptions store.LayerOptions, dest any) error {
	config := mapstructure.DecoderConfig{
		Result:     dest,
		ZeroFields: true,
		DecodeHook: mapstructure.ComposeDecodeHookFunc(
			toDurationHookFunc(),
		),
	}

	decoder, err := mapstructure.NewDecoder(&config)
	if err != nil {
		return errors.WithStack(err)
	}

	if err := decoder.Decode(storeOptions); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

func toDurationHookFunc() mapstructure.DecodeHookFunc {
	return func(
		f reflect.Type,
		t reflect.Type,
		data interface{}) (interface{}, error) {
		if t != reflect.TypeOf(*new(time.Duration)) {
			return data, nil
		}

		switch f.Kind() {
		case reflect.String:
			return time.ParseDuration(data.(string))
		case reflect.Int64:
			return time.Duration(data.(int64) * int64(time.Second)), nil
		default:
			return data, nil
		}
		// Convert it by parsing
	}
}