package predictions

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

	"github.com/google/go-querystring/query"
	"go.fifitido.net/twitch/api/types"
)

type GetPredictionsParams struct {
	// The ID of the broadcaster whose predictions you want to get. This ID must match the user ID in the user access token.
	BroadcasterID string `url:"broadcaster_id"`

	// The ID of the prediction to get.
	// To specify more than one ID, include this parameter for each prediction you want to get. For example, id=1234&id=5678.
	// You may specify a maximum of 25 IDs. The endpoint ignores duplicate IDs and those not owned by the broadcaster.
	IDs []string `url:"id,omitempty"`

	// The maximum number of items to return per page in the response.
	// The minimum page size is 1 item per page and the maximum is 25 items per page.
	// The default is 20.
	First *int `url:"first,omitempty"`

	// The cursor used to get the next page of results.
	// The Pagination object in the response contains the cursor’s value.
	// Read More: https://dev.twitch.tv/docs/api/guide#pagination
	After *types.Cursor `url:"after,omitempty"`
}

type GetPredictionsResponse struct {
	// The broadcaster’s list of Channel Points Predictions.
	// The list is sorted in descending ordered by when the prediction began (the most recent prediction is first).
	// The list is empty if the broadcaster hasn’t created predictions.
	Data []Prediction `json:"data"`

	// A pagination object that contains the cursor to use to get the next page of results.
	// The object is empty if there are no more pages left to page through.
	// Read More: https://dev.twitch.tv/docs/api/guide#pagination
	Pagination types.Pagination `json:"pagination"`
}

// Gets a list of Channel Points Predictions that the broadcaster created.
//
// Requires a user access token that includes the channel:read:predictions or channel:manage:predictions scope.
func (c *Predictions) GetPredictions(ctx context.Context, params *GetPredictionsParams) (*GetPredictionsResponse, error) {
	v, _ := query.Values(params)
	endpoint := c.baseUrl.ResolveReference(&url.URL{Path: "predictions", RawQuery: v.Encode()})

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
	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 get predictions (%d)", res.StatusCode)
	}

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

	return &data, nil
}