package api

import (
	"context"

	"connectrpc.com/connect"
	"github.com/tigorlazuardi/bluemage/go/gen/reddit"
	"github.com/tigorlazuardi/bluemage/go/pkg/errs"
	"github.com/tigorlazuardi/bluemage/go/pkg/log"
	"github.com/tigorlazuardi/bluemage/go/pkg/telemetry"
)

type SubredditResolveNameRequest struct {
	Name string
	Type string
}

func (api *API) SubredditResolveName(ctx context.Context, request SubredditResolveNameRequest) (resolved string, err error) {
	ctx, span := tracer.Start(ctx, "SubredditResolveName")
	defer func() { telemetry.EndWithStatus(span, err) }()

	ctx, httplog := log.ContextWithRoundTripCollector(ctx)
	typ := reddit.GetListingTypeR
	if request.Type == "user" {
		typ = reddit.GetListingTypeUser
	}

	resp, err := api.Reddit.GetListing(ctx, reddit.GetListingParams{
		Type: typ,
		Name: request.Name,
	})
	if err != nil {
		err = errs.Wrapw(err, "failed to get listing from reddit", "round_trip", httplog)
		return resolved, err
	}

	switch resp := resp.(type) {
	case *reddit.GetListingForbidden:
		err = errs.
			Failw(
				"subreddit is private",
				"round_trip", httplog,
			).
			Code(connect.CodePermissionDenied)
		return resolved, err
	case *reddit.GetListingTooManyRequests:
		err = errs.
			Failw(
				"too many requests error response from reddit",
				"round_trip", httplog,
			).
			Code(connect.CodeResourceExhausted)
		return resolved, err
	case *reddit.ListingResponse:
		if !isValidSubreddit(resp) {
			err = errs.
				Failf("subreddit '%s' of type '%s' seems to be empty or not valid", request.Name, request.Type).
				Details("round_trip", httplog).
				Code(connect.CodeNotFound)
			return resolved, err
		}
		data := resp.Data.Children[0].Data
		if request.Type == "user" {
			return data.Author, nil
		}
		return data.Subreddit, nil
	default:
		err = errs.
			Failw("unexpected response from reddit", "round_trip", httplog)
		return resolved, err
	}
}

func isValidSubreddit(list *reddit.ListingResponse) bool {
	return list.Data.After.Null && len(list.Data.Children) == 0
}