package main

import (
	"strings"
	"testing"
	"time"

	"golang.org/x/net/html"
)

func TestInferAssignmentDate(t *testing.T) {
	now := time.Date(2026, 3, 28, 10, 0, 0, 0, time.UTC)
	got := inferAssignmentDate("Jan 20", now)
	want := time.Date(2026, 1, 20, 0, 0, 0, 0, time.UTC)
	if !got.Equal(want) {
		t.Fatalf("got %s want %s", got, want)
	}
}

func TestInferAssignmentDateRollsBackYear(t *testing.T) {
	now := time.Date(2026, 3, 28, 10, 0, 0, 0, time.UTC)
	got := inferAssignmentDate("Dec 15", now)
	want := time.Date(2025, 12, 15, 0, 0, 0, 0, time.UTC)
	if !got.Equal(want) {
		t.Fatalf("got %s want %s", got, want)
	}
}

func TestInferUpcomingDateRollsForwardYear(t *testing.T) {
	now := time.Date(2026, 12, 28, 10, 0, 0, 0, time.UTC)
	got := inferUpcomingDate("Jan 03", now)
	want := time.Date(2027, 1, 3, 0, 0, 0, 0, time.UTC)
	if !got.Equal(want) {
		t.Fatalf("got %s want %s", got, want)
	}
}

func TestFilterUpcomingAssignments(t *testing.T) {
	now := time.Date(2026, 3, 28, 10, 0, 0, 0, time.UTC)
	assignments := []Assignment{
		{DueDate: time.Date(2026, 3, 29, 0, 0, 0, 0, time.UTC), Title: "Soon"},
		{DueDate: time.Date(2026, 4, 20, 0, 0, 0, 0, time.UTC), Title: "Later"},
	}
	got := filterUpcomingAssignments(assignments, now, 14)
	if len(got) != 1 || got[0].Title != "Soon" {
		t.Fatalf("unexpected filtered assignments: %#v", got)
	}
}

func TestDedupeAssignments(t *testing.T) {
	assignment := Assignment{
		DueDate: time.Date(2026, 4, 1, 0, 0, 0, 0, time.UTC),
		Title:   "Preparedness",
		Link:    "https://example.invalid/a",
	}
	got := dedupeAssignments([]Assignment{assignment, assignment})
	if len(got) != 1 {
		t.Fatalf("got %d items", len(got))
	}
}

func TestExtractLikeLiveMissingTable(t *testing.T) {
	doc := mustParseHTML(`
<table class="pure-table pure-table-horizontal missing-assignments">
  <tbody>
    <tr>
      <td>Mar<br>25</td>
      <td>
        <small><a href="/class/1">US History</a></small>
        <a data-alma-modal="StudentAssignmentDetailsModal" href="/assignment/1">HW: Timeline Events</a>
      </td>
      <td><i title="Missing"></i></td>
    </tr>
  </tbody>
</table>`)

	table := findNode(doc, func(n *html.Node) bool {
		return n.Type == html.ElementNode && n.Data == "table" && hasClass(n, "missing-assignments")
	})
	if table == nil {
		t.Fatal("missing table not found")
	}
	row := findNode(table, func(n *html.Node) bool { return n.Type == html.ElementNode && n.Data == "tr" })
	cells := directChildrenByTag(row, "td")
	if got := nodeText(cells[0]); got != "Mar 25" {
		t.Fatalf("got %q", got)
	}
	link := findNode(cells[1], func(n *html.Node) bool {
		return n.Type == html.ElementNode && n.Data == "a" && attr(n, "data-alma-modal") != ""
	})
	if got := nodeText(link); got != "HW: Timeline Events" {
		t.Fatalf("got %q", got)
	}
}

func mustParseHTML(text string) *html.Node {
	doc, err := html.Parse(strings.NewReader(text))
	if err != nil {
		panic(err)
	}
	return doc
}