package docs

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

var now = time.Date(2026, 10, 23, 20, 45, 12, 345_000_000, time.UTC)

// TestNewTemplates checks that fresh records fail only on their markers and
// become valid once those are replaced.
func TestNewTemplates(t *testing.T) {
	for _, tt := range []struct {
		kind, path string
		markers    int
	}{
		{"adr", "docs/adr/20261023T204512345Z-use-x-y.md", 6},
		{"plan", "docs/plans/20261023T204512345Z-use-x-y.md", 3},
	} {
		t.Run(tt.kind, func(t *testing.T) {
			root := t.TempDir()
			path, err := New(root, tt.kind, `Use "X" & Y`, now)
			must(t, err)
			if path != tt.path {
				t.Fatalf("path = %s", path)
			}
			res, err := Check(root)
			must(t, err)
			if len(res.Problems) != tt.markers {
				t.Fatalf("got %v, want %d marker problems", res.Problems, tt.markers)
			}
			for _, p := range res.Problems {
				if !strings.Contains(p.Msg, marker) {
					t.Errorf("not a marker problem: %s", p)
				}
			}
			data, err := os.ReadFile(filepath.Join(root, path))
			must(t, err)
			must(t, os.WriteFile(filepath.Join(root, path), []byte(strings.ReplaceAll(string(data), marker, "x")), 0o644))
			res, err = Check(root)
			must(t, err)
			expect(t, res.Problems, nil)
		})
	}
}

func TestNewCollisions(t *testing.T) {
	root := t.TempDir()
	first, err := New(root, "adr", "Same", now)
	must(t, err)
	second, err := New(root, "adr", "Same", now)
	must(t, err)
	// The same stem in the other directory also advances the timestamp.
	third, err := New(root, "plan", "Same", now)
	must(t, err)
	want := []string{
		"docs/adr/20261023T204512345Z-same.md",
		"docs/adr/20261023T204512346Z-same.md",
		"docs/plans/20261023T204512347Z-same.md",
	}
	for i, got := range []string{first, second, third} {
		if got != want[i] {
			t.Errorf("file %d = %s, want %s", i, got, want[i])
		}
	}
	// Advancing across midnight keeps the date equal to the filename.
	root = t.TempDir()
	_, err = New(root, "adr", "Edge", time.Date(2026, 10, 23, 23, 59, 59, 999_000_000, time.UTC))
	must(t, err)
	got, err := New(root, "adr", "Edge", time.Date(2026, 10, 23, 23, 59, 59, 999_000_000, time.UTC))
	must(t, err)
	if got != "docs/adr/20261024T000000000Z-edge.md" {
		t.Fatalf("got %s", got)
	}
	res, err := Check(root)
	must(t, err)
	for _, p := range res.Problems {
		if !strings.Contains(p.Msg, marker) {
			t.Errorf("unexpected %s", p)
		}
	}
}

func TestNewRejectsBadTitles(t *testing.T) {
	for _, title := range []string{"", "  ", "a\nb", "!!!", "Drop C #", "#", "C ##"} {
		if path, err := New(t.TempDir(), "adr", title, now); err == nil {
			t.Errorf("title %q created %s", title, path)
		}
	}
}

func TestSlugify(t *testing.T) {
	for in, want := range map[string]string{"Use X, Y & Z!": "use-x-y-z", "  --Hello--  ": "hello", "Ünï": "n"} {
		if got := slugify(in); got != want {
			t.Errorf("slugify(%q) = %q, want %q", in, got, want)
		}
	}
	if got := slugify(strings.Repeat("ab ", 40)); len(got) != maxSlug || strings.HasSuffix(got, "-") {
		t.Errorf("long slug = %q", got)
	}
}