package conduit

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"

	"go.fifitido.net/twitch/api/eventsub"
)

type UpdateConduitShardsRequest struct {
	// Conduit ID.
	ConduitID string `json:"conduit_id"`

	// List of Shards to update.
	Shards []ShardUpdate `json:"shards"`
}

type ShardUpdate struct {
	// Shard ID.
	ID string `json:"id"`

	// The transport details that you want Twitch to use when sending you notifications.
	//
	// Does not support conduit transport type.
	Transport *eventsub.Transport `json:"transport"`
}

type UpdateConduitShardsResponse struct {
	// List of successful shard updates.
	Data []ConduitData `json:"data"`

	// List of unsuccessful updates.
	Errors []UpdateConduitShardsError `json:"errors"`
}

type UpdateConduitShardsError struct {
	// Shard ID.
	ID string `json:"id"`

	// The error that occurred while updating the shard.
	// Possible errors:
	//
	// The length of the string in the secret field is not valid.
	//
	// The URL in the transport's callback field is not valid. The URL must use the HTTPS protocol and the 443 port number.
	//
	// The value specified in the method field is not valid.
	//
	// The callback field is required if you specify the webhook transport method.
	//
	// The session_id field is required if you specify the WebSocket transport method.
	//
	// The websocket session is not connected.
	//
	// The shard id is outside of the conduit’s range.
	Message string `json:"message"`

	// Error codes used to represent a specific error condition while attempting to update shards.
	Code string `json:"code"`
}

// Updates shard(s) for a conduit.
//
// NOTE: Shard IDs are indexed starting at 0, so a conduit with a shard_count of 5 will have shards with IDs 0 through 4.
//
// Requires an app access token.
func (c *Conduit) UpdateConduitShards(ctx context.Context, body *UpdateConduitShardsRequest) (*UpdateConduitShardsResponse, error) {
	endpoint := c.baseUrl.ResolveReference(&url.URL{Path: "eventsub/conduits/shards"})

	r, w := io.Pipe()

	go func() {
		if err := json.NewEncoder(w).Encode(body); err != nil {
			w.CloseWithError(err)
		} else {
			w.Close()
		}
	}()

	req, err := http.NewRequestWithContext(ctx, http.MethodPatch, endpoint.String(), r)
	if err != nil {
		return nil, err
	}

	res, err := c.client.Do(req)
	if err != nil {
		return nil, err
	}
	defer res.Body.Close()

	statusOK := res.StatusCode >= 200 && res.StatusCode < 300
	if !statusOK {
		return nil, fmt.Errorf("failed to update conduit shards (%d)", res.StatusCode)
	}

	var data UpdateConduitShardsResponse
	if err := json.NewDecoder(res.Body).Decode(&data); err != nil {
		return nil, err
	}

	return &data, nil
}