package web

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"

	"donniemarko/internal/note"
	"donniemarko/internal/render"
	"donniemarko/internal/service"
	"donniemarko/internal/storage"
)

type testEnv struct {
	handler *Handler
	storage *storage.NoteStorage
}

func newTestEnv(t *testing.T) *testEnv {
	t.Helper()

	ns := storage.NewNoteStorage()

	notes := []*note.Note{
		{
			ID:        "a1",
			Title:     "Alpha",
			Content:   "# Alpha\ncontent",
			Path:      "notes/alpha.md",
			UpdatedAt: time.Date(2025, 12, 31, 10, 0, 0, 0, time.UTC),
		},
		{
			ID:        "b2",
			Title:     "Beta",
			Content:   "# Beta\nRust tips",
			Path:      "dev/beta.md",
			UpdatedAt: time.Date(2026, 1, 1, 10, 0, 0, 0, time.UTC),
		},
		{
			ID:        "z9",
			Title:     "Zulu",
			Content:   "# Zulu\nRust book",
			Path:      "notes/zulu.md",
			UpdatedAt: time.Date(2026, 1, 2, 10, 0, 0, 0, time.UTC),
		},
	}

	for _, n := range notes {
		if err := ns.Create(n); err != nil {
			t.Fatalf("create note: %v", err)
		}
	}

	svc := service.NewNoteService()
	svc.SetStorage(ns)

	tm := render.NewTemplateManager("templates")
	handler := NewHandler(svc, tm)

	return &testEnv{
		handler: handler,
		storage: ns,
	}
}

func assertOrder(t *testing.T, body string, want []string) {
	t.Helper()

	prev := -1
	for _, title := range want {
		idx := strings.Index(body, title)
		if idx == -1 {
			t.Fatalf("expected to find %q in response body", title)
		}
		if idx <= prev {
			t.Fatalf("expected %q to appear after previous title", title)
		}
		prev = idx
	}
}

func noteMarker(id string) string {
	return `data-hash="` + id + `"`
}

func groupSection(body, name string) string {
	header := `<h3 class="note-group">` + name + `</h3>`
	start := strings.Index(body, header)
	if start == -1 {
		return ""
	}
	rest := body[start+len(header):]
	next := strings.Index(rest, `<h3 class="note-group">`)
	if next == -1 {
		return rest
	}
	return rest[:next]
}

func TestHandlerRoot_DefaultSortRecent(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	if ct := rec.Header().Get("Content-Type"); ct != "text/html; charset=utf-8" {
		t.Fatalf("expected content-type text/html; charset=utf-8, got %q", ct)
	}

	body := rec.Body.String()
	if !strings.Contains(body, `<h3 class="note-group">dev</h3>`) {
		t.Fatalf("expected dev group header")
	}
	if !strings.Contains(body, `<h3 class="note-group">notes</h3>`) {
		t.Fatalf("expected notes group header")
	}

	devSection := groupSection(body, "dev")
	if devSection == "" {
		t.Fatalf("expected dev section")
	}
	assertOrder(t, devSection, []string{noteMarker("b2")})

	notesSection := groupSection(body, "notes")
	if notesSection == "" {
		t.Fatalf("expected notes section")
	}
	assertOrder(t, notesSection, []string{noteMarker("z9"), noteMarker("a1")})
}

func TestHandlerRoot_SortAlpha(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/?sort=alpha", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	devSection := groupSection(body, "dev")
	if devSection == "" {
		t.Fatalf("expected dev section")
	}
	assertOrder(t, devSection, []string{noteMarker("b2")})

	notesSection := groupSection(body, "notes")
	if notesSection == "" {
		t.Fatalf("expected notes section")
	}
	assertOrder(t, notesSection, []string{noteMarker("a1"), noteMarker("z9")})
}

func TestHandlerRoot_Search(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/?search=rust&sort=alpha", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "Matching results for query 'rust'") {
		t.Fatalf("expected search header to be rendered")
	}

	if strings.Contains(body, `data-hash="a1"`) {
		t.Fatalf("expected non-matching note to be excluded")
	}

	assertOrder(t, body, []string{noteMarker("b2"), noteMarker("z9")})
}

func TestHandlerNotes_Success(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/notes/b2", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "<h1>Beta</h1>") {
		t.Fatalf("expected rendered markdown for note content")
	}
	if !strings.Contains(body, `class="active-note"`) {
		t.Fatalf("expected active note class in list")
	}
	if !strings.Contains(body, `data-hash="b2"`) {
		t.Fatalf("expected active note hash in list")
	}
}

func TestHandlerNotes_NotFound(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/notes/missing", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusNotFound {
		t.Fatalf("expected status 404, got %d", rec.Code)
	}

	if !strings.Contains(rec.Body.String(), "Note not found") {
		t.Fatalf("expected not found message")
	}
}

func TestHandler_NotFoundPath(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/nope", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusNotFound {
		t.Fatalf("expected status 404, got %d", rec.Code)
	}
}

func TestExtractHash(t *testing.T) {
	cases := []struct {
		name string
		path string
		want string
	}{
		{
			name: "valid note path",
			path: "/notes/abcd",
			want: "abcd",
		},
		{
			name: "missing hash",
			path: "/notes/",
			want: "",
		},
		{
			name: "wrong prefix",
			path: "/other/abcd",
			want: "",
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := extractHash(tc.path); got != tc.want {
				t.Fatalf("expected %q, got %q", tc.want, got)
			}
		})
	}
}

func TestHandlerTags_Add(t *testing.T) {
	env := newTestEnv(t)

	form := url.Values{}
	form.Set("tag", " Go ")
	req := httptest.NewRequest(http.MethodPost, "/notes/b2/tags", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("expected status 303, got %d", rec.Code)
	}

	n, err := env.storage.Get("b2")
	if err != nil {
		t.Fatalf("get note: %v", err)
	}
	if len(n.Tags) != 1 || n.Tags[0] != "go" {
		t.Fatalf("expected normalized tag on note, got %+v", n.Tags)
	}
}

func TestHandlerTags_Remove(t *testing.T) {
	env := newTestEnv(t)

	if err := env.storage.AddTag("b2", "go"); err != nil {
		t.Fatalf("seed tag: %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/notes/b2/tags/go", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("expected status 303, got %d", rec.Code)
	}

	n, err := env.storage.Get("b2")
	if err != nil {
		t.Fatalf("get note: %v", err)
	}
	if len(n.Tags) != 0 {
		t.Fatalf("expected tag to be removed, got %+v", n.Tags)
	}
}

func TestHandlerRoot_TagFilter(t *testing.T) {
	env := newTestEnv(t)

	if err := env.storage.AddTag("a1", "go"); err != nil {
		t.Fatalf("seed tag: %v", err)
	}
	if err := env.storage.AddTag("b2", "rust"); err != nil {
		t.Fatalf("seed tag: %v", err)
	}

	req := httptest.NewRequest(http.MethodGet, "/?tag=go", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	if strings.Contains(body, noteMarker("b2")) {
		t.Fatalf("expected non-matching note to be excluded")
	}
	if !strings.Contains(body, noteMarker("a1")) {
		t.Fatalf("expected matching note to be included")
	}
}

func TestHandlerRoot_RendersActiveNote(t *testing.T) {
	env := newTestEnv(t)

	req := httptest.NewRequest(http.MethodGet, "/?search=rust&active=b2", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "<h1>Beta</h1>") {
		t.Fatalf("expected rendered active note content")
	}
}

func TestHandlerRoot_RendersRootGroupHeader(t *testing.T) {
	env := newTestEnv(t)

	rootNote := &note.Note{
		ID:        "r1",
		Title:     "Root Note",
		Content:   "# Root\ncontent",
		Path:      "root.md",
		UpdatedAt: time.Date(2026, 1, 3, 10, 0, 0, 0, time.UTC),
	}

	if err := env.storage.Create(rootNote); err != nil {
		t.Fatalf("create note: %v", err)
	}

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	rec := httptest.NewRecorder()

	env.handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("expected status 200, got %d", rec.Code)
	}

	body := rec.Body.String()
	if !strings.Contains(body, `<h3 class="note-group">root</h3>`) {
		t.Fatalf("expected root group header")
	}
	if !strings.Contains(body, noteMarker("r1")) {
		t.Fatalf("expected root note to be rendered")
	}
}

func TestRootFolderName(t *testing.T) {
	cases := []struct {
		name string
		path string
		want string
	}{
		{name: "empty", path: "", want: "root"},
		{name: "dot", path: ".", want: "root"},
		{name: "file at root", path: "bookmarks.md", want: "root"},
		{name: "single", path: "notes/file.md", want: "notes"},
		{name: "nested", path: "dev/ideas/note.md", want: "dev"},
		{name: "absolute", path: "/writings/notes/a.md", want: "writings"},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := rootFolderName(tc.path); got != tc.want {
				t.Fatalf("expected %q, got %q", tc.want, got)
			}
		})
	}
}

func TestGroupNotesByFolder(t *testing.T) {
	notes := []*note.Note{
		{ID: "a1", Title: "Alpha", Path: "notes/a.md"},
		{ID: "b2", Title: "Beta", Path: "dev/b.md"},
		{ID: "c3", Title: "Gamma", Path: "notes/c.md"},
	}

	groups := groupNotesByFolder(notes)
	if len(groups) != 2 {
		t.Fatalf("expected 2 groups, got %d", len(groups))
	}

	if groups[0].Name != "dev" || len(groups[0].Notes) != 1 {
		t.Fatalf("unexpected dev group: %+v", groups[0])
	}
	if groups[1].Name != "notes" || len(groups[1].Notes) != 2 {
		t.Fatalf("unexpected notes group: %+v", groups[1])
	}
}