package main

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

// grouped writes a whole number with a comma every three digits
func grouped(n int64) string {
	s := strconv.FormatInt(n, 10)
	for i := len(s) - 3; i > 0; i -= 3 {
		s = s[:i] + "," + s[i:]
	}
	return s
}

func main() {
	// Read NVDA's file (one GET, no key), naming your own project
	req, err := http.NewRequest("GET",
		"https://tickerinside.com/api/v1/sec/nvda.json", nil)
	if err != nil {
		log.Fatal(err)
	}
	req.Header.Set("User-Agent", "MyProject/1.0 (+https://example.com)")
	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		log.Fatalf("HTTP %d", resp.StatusCode)
	}

	// The etf_ownership block holds the figure; decode the fields used here
	var stock struct {
		Own struct {
			PctLowerBound         *float64 `json:"pct_lower_bound"`
			Refused               string   `json:"refused"`
			Basis                 string   `json:"basis"`
			SharesHeld            int64    `json:"shares_held"`
			SharesOutstanding     int64    `json:"shares_outstanding"`
			SharesOutstandingAsOf string   `json:"shares_outstanding_as_of"`
			HoldingsDates         struct {
				Oldest string `json:"oldest"`
				Newest string `json:"newest"`
			} `json:"holdings_dates"`
			CiteAs string `json:"cite_as"`
		} `json:"etf_ownership"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&stock); err != nil {
		log.Fatal(err)
	}
	own := stock.Own

	// pct_lower_bound is null when no figure is published, and refused says
	// why
	if own.PctLowerBound == nil {
		fmt.Println("NVDA etf_ownership: no figure published, refused",
			own.Refused)
		return
	}
	fmt.Printf("NVDA etf_ownership: at least %v%% of its shares held by "+
		"covered US ETFs, basis %s\n", *own.PctLowerBound, own.Basis)
	// The shares counted, and the date of the count of shares outstanding
	fmt.Println("shares_held", grouped(own.SharesHeld), "shares_outstanding",
		grouped(own.SharesOutstanding), "as of", own.SharesOutstandingAsOf)
	// The oldest and the newest holdings file behind the figure
	fmt.Println("holdings dated", own.HoldingsDates.Oldest, "to",
		own.HoldingsDates.Newest)
	// The line to print under the figure
	fmt.Println(own.CiteAs)
}