package attendance

import (
	"context"
	"encoding/csv"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"
)

func TestClientFetchAdults(t *testing.T) {
	data, err := os.ReadFile("testdata/adults_minimal.csv")
	if err != nil {
		t.Fatal(err)
	}
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		_, _ = w.Write(data)
	}))
	defer srv.Close()

	// Point the client at our test server by re-implementing fetch against its URL.
	rows, err := fetchURL(context.Background(), srv.Client(), srv.URL)
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) < 2 {
		t.Fatalf("want ≥2 rows, got %d", len(rows))
	}
	if rows[0][0] != "Jméno" {
		t.Errorf("unexpected header: %q", rows[0][0])
	}
}

func TestFake(t *testing.T) {
	adultRows := parseCSV(t, "testdata/adults_minimal.csv")
	juniorRows := parseCSV(t, "testdata/juniors_minimal.csv")

	f := &Fake{Adults: adultRows, Juniors: juniorRows}

	got, err := f.FetchAdults(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if got[0][0] != "Jméno" {
		t.Errorf("adults header: %q", got[0][0])
	}

	got, err = f.FetchJuniors(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	if got[1][0] != "Junior One" {
		t.Errorf("juniors first member: %q", got[1][0])
	}
}

func parseCSV(t *testing.T, path string) [][]string {
	t.Helper()
	b, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	r := csv.NewReader(strings.NewReader(string(b)))
	r.FieldsPerRecord = -1
	rows, err := r.ReadAll()
	if err != nil {
		t.Fatal(err)
	}
	return rows
}

// fetchURL is a test helper that exercises the shared fetch logic against an arbitrary URL.
func fetchURL(ctx context.Context, hc *http.Client, url string) ([][]string, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	resp, err := hc.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	r := csv.NewReader(strings.NewReader(string(b)))
	r.FieldsPerRecord = -1
	return r.ReadAll()
}