package wiki

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"time"
)

const userAgent = "rsw-cli/1.0 (RuneScape Wiki CLI tool; https://github.com/runescape-wiki/rsw)"

// Client wraps HTTP requests to the MediaWiki API.
type Client struct {
	baseURL    string
	httpClient *http.Client
}

// NewClient creates a wiki API client for the given base URL.
func NewClient(baseURL string) *Client {
	return &Client{
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 15 * time.Second,
		},
	}
}

// get performs a GET request with the given parameters and decodes JSON into dest.
func (c *Client) get(params url.Values, dest interface{}) error {
	params.Set("format", "json")

	reqURL := fmt.Sprintf("%s?%s", c.baseURL, params.Encode())
	req, err := http.NewRequest("GET", reqURL, nil)
	if err != nil {
		return fmt.Errorf("creating request: %w", err)
	}
	req.Header.Set("User-Agent", userAgent)

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("executing request: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
	}

	if err := json.NewDecoder(resp.Body).Decode(dest); err != nil {
		return fmt.Errorf("decoding response: %w", err)
	}

	return nil
}