package main

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

// The fields of a fund file this example uses
type fund struct {
	HoldingsAsOf string             `json:"holdings_as_of"`
	Holdings     map[string]float64 `json:"holdings"`
	CiteAs       string             `json:"cite_as"`
}

func main() {
	// Read both funds' files; each has the date of its own issuer's file
	client := &http.Client{Timeout: 30 * time.Second}
	tickers := []string{"VOO", "QQQ"}
	funds := map[string]fund{}
	for _, ticker := range tickers {
		req, err := http.NewRequest("GET", "https://tickerinside.com/api/v1/fund/"+
			strings.ToLower(ticker)+".json", nil)
		if err != nil {
			log.Fatal(err)
		}
		req.Header.Set("User-Agent", "MyProject/1.0 (+https://example.com)")
		resp, err := client.Do(req)
		if err != nil {
			log.Fatal(err)
		}
		if resp.StatusCode != http.StatusOK {
			log.Fatalf("HTTP %d for %s", resp.StatusCode, ticker)
		}
		var f fund
		err = json.NewDecoder(resp.Body).Decode(&f)
		resp.Body.Close()
		if err != nil {
			log.Fatal(err)
		}
		funds[ticker] = f
		fmt.Println(ticker, "holdings_as_of", f.HoldingsAsOf)
	}

	// Overlap by weight, as the site computes it: for every ticker both
	// funds hold, add the smaller of its two weights
	a, b := funds["VOO"].Holdings, funds["QQQ"].Holdings
	overlap, shared := 0.0, 0
	for t, wa := range a {
		if wb, ok := b[t]; ok {
			overlap += min(wa, wb)
			shared++
		}
	}
	fmt.Printf("overlap by weight %.1f%%, %d companies in both\n",
		overlap, shared)

	// The lines to print under the figure, one per fund file
	for _, ticker := range tickers {
		fmt.Println(funds[ticker].CiteAs)
	}
}