package main

import (
	"encoding/csv"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"

	"github.com/michaeldileo/SafelyYouCodingChallenge/internal/api"
	"github.com/michaeldileo/SafelyYouCodingChallenge/internal/store"
)

func main() {
	deviceIDs, err := loadDeviceIDs("devices.csv")
	if err != nil {
		log.Fatalf("load devices: %v", err)
	}

	s := store.New(deviceIDs)
	log.Printf("loaded %d known devices", len(deviceIDs))

	srv := api.NewServer(s)

	addr := ":6733"
	fmt.Println("listening on", addr)
	if err := http.ListenAndServe(addr, srv.Handler()); err != nil {
		log.Fatal(err)
	}
}

// loadDeviceIDs reads devices.csv (header + one device_id per row).
// Lives in main on purpose: startup I/O stays at the process edge;
// the store only receives already-parsed IDs.
func loadDeviceIDs(path string) ([]store.DeviceID, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	r := csv.NewReader(f)

	// Skip header: device_id
	if _, err := r.Read(); err != nil {
		return nil, fmt.Errorf("read header: %w", err)
	}

	var ids []store.DeviceID
	for {
		record, err := r.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		if len(record) == 0 || record[0] == "" {
			continue
		}
		ids = append(ids, store.DeviceID(record[0]))
	}
	return ids, nil
}