package finnhub

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

const baseURL = "https://finnhub.io/api/v1"

type Client struct {
	apiKey string
	http   *http.Client
}

type NewsItem struct {
	ID       int    `json:"id"`
	Category string `json:"category"`
	Datetime int64  `json:"datetime"`
	Headline string `json:"headline"`
	Related  string `json:"related"`
	Source   string `json:"source"`
	URL      string `json:"url"`
	Summary  string `json:"summary"`
}

func New(apiKey string) *Client {
	return &Client{
		apiKey: apiKey,
		http:   &http.Client{Timeout: 10 * time.Second},
	}
}

func (c *Client) CompanyNews(symbol, from, to string) ([]NewsItem, error) {
	url := fmt.Sprintf("%s/company-news?symbol=%s&from=%s&to=%s&token=%s",
		baseURL, symbol, from, to, c.apiKey)
	return c.fetchNews(url)
}

func (c *Client) MarketNews() ([]NewsItem, error) {
	url := fmt.Sprintf("%s/news?category=general&token=%s", baseURL, c.apiKey)
	return c.fetchNews(url)
}

func (c *Client) Ping() error {
	url := fmt.Sprintf("%s/news?category=general&minId=999999999&token=%s", baseURL, c.apiKey)
	resp, err := c.http.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode == 401 || resp.StatusCode == 403 {
		return fmt.Errorf("invalid API key (HTTP %d)", resp.StatusCode)
	}
	return nil
}

func (c *Client) fetchNews(url string) ([]NewsItem, error) {
	resp, err := c.http.Get(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("finnhub: HTTP %d", resp.StatusCode)
	}

	var items []NewsItem
	if err := json.NewDecoder(resp.Body).Decode(&items); err != nil {
		return nil, err
	}
	return items, nil
}