package web

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"keel/internal/settings"
)

// fakeApplier records the last settings it was asked to apply and can be told to
// reject with ErrInvalidBackend.
type fakeApplier struct {
	called int
	last   settings.Settings
	reject bool
}

func (f *fakeApplier) apply(s settings.Settings) error {
	if f.reject {
		return settings.ErrInvalidBackend
	}
	f.called++
	f.last = s
	return nil
}

func TestGetSettingsReturnsCurrent(t *testing.T) {
	s, _ := newTestServer(t)
	cur := settings.Settings{AIBackend: "claude", MarvinCmd: "am", KnowledgePath: "/tmp/k.md"}
	fa := &fakeApplier{}
	s.SetSettings(filepath.Join(t.TempDir(), "settings.json"), cur, fa.apply)
	r := s.Router()

	req := httptest.NewRequest(http.MethodGet, "/settings", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	var got settings.Settings
	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if got != cur {
		t.Errorf("got %+v, want %+v", got, cur)
	}
}

func TestPostSettingsValidAppliesAndSaves(t *testing.T) {
	s, _ := newTestServer(t)
	path := filepath.Join(t.TempDir(), "settings.json")
	fa := &fakeApplier{}
	s.SetSettings(path, settings.Settings{}, fa.apply)
	r := s.Router()

	body := `{"ai_backend":"codex","marvin_cmd":"uv run am","knowledge_path":"/tmp/k.md"}`
	w := post(t, r, "/settings", body)
	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body %s)", w.Code, w.Body.String())
	}
	if fa.called != 1 {
		t.Fatalf("applier called %d times, want 1", fa.called)
	}
	if fa.last.AIBackend != "codex" {
		t.Errorf("applied backend = %q, want codex", fa.last.AIBackend)
	}
	saved, err := settings.Load(path)
	if err != nil {
		t.Fatalf("settings file not loadable: %v", err)
	}
	if saved.AIBackend != "codex" || saved.MarvinCmd != "uv run am" || saved.KnowledgePath != "/tmp/k.md" {
		t.Errorf("saved settings = %+v, want codex/uv run am//tmp/k.md", saved)
	}
}

func TestPostSettingsInvalidBackendIs400AndNoSave(t *testing.T) {
	s, _ := newTestServer(t)
	path := filepath.Join(t.TempDir(), "settings.json")
	fa := &fakeApplier{reject: true}
	s.SetSettings(path, settings.Settings{}, fa.apply)
	r := s.Router()

	w := post(t, r, "/settings", `{"ai_backend":"bogus"}`)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400", w.Code)
	}
	if _, err := os.Stat(path); !os.IsNotExist(err) {
		t.Errorf("settings file should not exist after rejected save, stat err = %v", err)
	}
	if fa.called != 0 {
		t.Errorf("applier recorded %d successful applies, want 0", fa.called)
	}
}

func TestPostSettingsInvalidJSONIs400(t *testing.T) {
	s, _ := newTestServer(t)
	fa := &fakeApplier{}
	s.SetSettings(filepath.Join(t.TempDir(), "settings.json"), settings.Settings{}, fa.apply)
	r := s.Router()

	w := post(t, r, "/settings", `{not json`)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400", w.Code)
	}
	if fa.called != 0 {
		t.Errorf("applier called on invalid json; want 0, got %d", fa.called)
	}
}

func TestPostSettingsPreservesAWURL(t *testing.T) {
	s, _ := newTestServer(t)
	path := filepath.Join(t.TempDir(), "settings.json")
	fa := &fakeApplier{}
	cur := settings.Settings{AIBackend: "claude", AWURL: "http://aw.remote:9999"}
	s.SetSettings(path, cur, fa.apply)
	r := s.Router()

	// POST a body that omits aw_url (mirrors what the real UI form sends).
	body := `{"ai_backend":"claude","marvin_cmd":"","knowledge_path":""}`
	w := post(t, r, "/settings", body)
	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (body %s)", w.Code, w.Body.String())
	}
	if fa.called != 1 {
		t.Fatalf("applier called %d times, want 1", fa.called)
	}
	// (a) applyFn must have received the preserved AWURL.
	if fa.last.AWURL != "http://aw.remote:9999" {
		t.Errorf("applied AWURL = %q, want http://aw.remote:9999", fa.last.AWURL)
	}
	// (b) persisted file must also preserve the AWURL.
	saved, err := settings.Load(path)
	if err != nil {
		t.Fatalf("settings file not loadable: %v", err)
	}
	if saved.AWURL != "http://aw.remote:9999" {
		t.Errorf("saved AWURL = %q, want http://aw.remote:9999", saved.AWURL)
	}
}

func TestBrowseListsDirsAndMarkdown(t *testing.T) {
	dir := t.TempDir()
	if err := os.Mkdir(filepath.Join(dir, "sub"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "profile.md"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "notes.txt"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}

	s, _ := newTestServer(t)
	s.SetSettings(filepath.Join(t.TempDir(), "settings.json"), settings.Settings{}, func(settings.Settings) error { return nil })
	r := s.Router()

	req := httptest.NewRequest(http.MethodGet, "/fs/browse?dir="+dir, nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	var resp struct {
		Dir     string `json:"dir"`
		Parent  string `json:"parent"`
		Entries []struct {
			Name  string `json:"name"`
			Path  string `json:"path"`
			IsDir bool   `json:"is_dir"`
		} `json:"entries"`
	}
	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if resp.Parent != filepath.Dir(dir) {
		t.Errorf("parent = %q, want %q", resp.Parent, filepath.Dir(dir))
	}
	if resp.Dir != dir {
		t.Errorf("dir = %q, want %q", resp.Dir, dir)
	}
	var names []string
	hasSub, hasMd, hasTxt := false, false, false
	for _, e := range resp.Entries {
		names = append(names, e.Name)
		switch e.Name {
		case "sub":
			hasSub = e.IsDir
			if e.Path != filepath.Join(dir, e.Name) {
				t.Errorf("sub path = %q, want %q", e.Path, filepath.Join(dir, e.Name))
			}
		case "profile.md":
			hasMd = !e.IsDir
			if e.Path != filepath.Join(dir, e.Name) {
				t.Errorf("profile.md path = %q, want %q", e.Path, filepath.Join(dir, e.Name))
			}
		case "notes.txt":
			hasTxt = true
		}
	}
	if !hasSub || !hasMd {
		t.Errorf("missing dir or .md entry; names = %v", names)
	}
	if hasTxt {
		t.Errorf(".txt should be filtered out; names = %v", names)
	}
}

func TestBrowseBadDirIs400(t *testing.T) {
	s, _ := newTestServer(t)
	s.SetSettings(filepath.Join(t.TempDir(), "settings.json"), settings.Settings{}, func(settings.Settings) error { return nil })
	r := s.Router()
	req := httptest.NewRequest(http.MethodGet, "/fs/browse?dir=/no/such/dir/xyz", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400", w.Code)
	}
}