package server

import (
	"bufio"
	"bytes"
	"encoding/json"
	"io"
	"log"
	"net/http"
	"net/http/httptest"
	"net/url"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"cc.tiredsysadmin.keeporg/internal/secret"
	"cc.tiredsysadmin.keeporg/internal/store"
	"cc.tiredsysadmin.keeporg/internal/totp"
)

type harness struct {
	t    *testing.T
	srv  *Server
	http *httptest.Server
}

const adminPassword = "admin-password-1"

func newHarness(t *testing.T) *harness {
	t.Helper()
	dir := t.TempDir()
	srv, err := New(Config{DataDir: dir, ExternalURL: "https://keeporg.test"},
		log.New(io.Discard, "", 0))
	if err != nil {
		t.Fatal(err)
	}
	hash, err := secret.Hash(adminPassword)
	if err != nil {
		t.Fatal(err)
	}
	if err := srv.Store().Update(func(st *store.State) error {
		st.Users["admin"] = &store.User{ID: "admin", Username: "admin", PassHash: hash, ServerAdmin: true}
		st.Groups["everyone"] = &store.Group{ID: "everyone", Name: "everyone"}
		st.Memberships = append(st.Memberships,
			store.Membership{UserID: "admin", GroupID: "everyone", Role: store.RoleAdmin})
		return nil
	}); err != nil {
		t.Fatal(err)
	}
	ts := httptest.NewServer(srv.Handler())
	t.Cleanup(ts.Close)
	_ = filepath.Join(dir, "state.json")
	return &harness{t: t, srv: srv, http: ts}
}

// call sends a JSON request and decodes the JSON response.
func (h *harness) call(method, path, token string, body any) (int, map[string]any) {
	h.t.Helper()
	var rdr io.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			h.t.Fatal(err)
		}
		rdr = bytes.NewReader(b)
	}
	req, err := http.NewRequest(method, h.http.URL+path, rdr)
	if err != nil {
		h.t.Fatal(err)
	}
	if token != "" {
		req.Header.Set("Authorization", "Bearer "+token)
	}
	resp, err := h.http.Client().Do(req)
	if err != nil {
		h.t.Fatal(err)
	}
	defer resp.Body.Close()
	out := map[string]any{}
	raw, _ := io.ReadAll(resp.Body)
	if len(raw) > 0 {
		_ = json.Unmarshal(raw, &out)
	}
	return resp.StatusCode, out
}

func (h *harness) login(user, password, code string) (string, int, map[string]any) {
	h.t.Helper()
	status, body := h.call("POST", "/api/v1/auth/login", "",
		map[string]string{"username": user, "password": password, "totp": code, "label": "test"})
	tok, _ := body["token"].(string)
	return tok, status, body
}

// push uploads bytes with an explicit If-Match and returns the response.
func (h *harness) push(token, dbID, ifMatch string, data []byte) (int, map[string]any, http.Header) {
	h.t.Helper()
	req, err := http.NewRequest("PUT", h.http.URL+"/api/v1/databases/"+dbID+"/blob", bytes.NewReader(data))
	if err != nil {
		h.t.Fatal(err)
	}
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("If-Match", ifMatch)
	resp, err := h.http.Client().Do(req)
	if err != nil {
		h.t.Fatal(err)
	}
	defer resp.Body.Close()
	out := map[string]any{}
	raw, _ := io.ReadAll(resp.Body)
	_ = json.Unmarshal(raw, &out)
	return resp.StatusCode, out, resp.Header
}

// makeDB creates a database owned by the "everyone" group.
func (h *harness) makeDB(token, name string) string {
	h.t.Helper()
	status, body := h.call("POST", "/api/v1/databases", token,
		map[string]string{"name": name, "owner_group_id": "everyone"})
	if status != http.StatusCreated {
		h.t.Fatalf("create database: %d %v", status, body)
	}
	return body["id"].(string)
}

func TestLoginRejectsWrongPassword(t *testing.T) {
	h := newHarness(t)
	if _, status, _ := h.login("admin", "nope", ""); status != http.StatusUnauthorized {
		t.Fatalf("status = %d", status)
	}
	tok, status, _ := h.login("admin", adminPassword, "")
	if status != http.StatusOK || tok == "" {
		t.Fatalf("status = %d token = %q", status, tok)
	}
}

func TestPushPullAndServerWinsConflict(t *testing.T) {
	h := newHarness(t)
	tok, _, _ := h.login("admin", adminPassword, "")
	db := h.makeDB(tok, "Team")

	status, body, hdr := h.push(tok, db, `"0"`, []byte("kdbx-v1"))
	if status != http.StatusOK || body["version"].(float64) != 1 {
		t.Fatalf("first push: %d %v", status, body)
	}
	if hdr.Get("ETag") != `"1"` {
		t.Fatalf("etag = %q", hdr.Get("ETag"))
	}

	// A second client that still believes it is on version 0 is refused, and
	// learns both the current version and the policy to apply.
	status, body, hdr = h.push(tok, db, `"0"`, []byte("kdbx-other"))
	if status != http.StatusConflict || body["code"] != "conflict" {
		t.Fatalf("stale push: %d %v", status, body)
	}
	if body["current_version"].(float64) != 1 || body["merge_strategy"] != "server-wins" {
		t.Fatalf("conflict body = %v", body)
	}
	if hdr.Get("X-KeepOrg-Strategy") != "server-wins" {
		t.Fatalf("strategy header = %q", hdr.Get("X-KeepOrg-Strategy"))
	}

	// Forcing is refused while the strategy is server-wins.
	if status, _, _ = h.push(tok, db, "*", []byte("forced")); status != http.StatusConflict {
		t.Fatalf("force under server-wins: %d", status)
	}

	// Re-pushing identical bytes is a no-op, so a save that changed nothing
	// does not burn a version.
	status, body, _ = h.push(tok, db, `"1"`, []byte("kdbx-v1"))
	if status != http.StatusOK || body["unchanged"] != true || body["version"].(float64) != 1 {
		t.Fatalf("idempotent push: %d %v", status, body)
	}

	// Download returns exactly what was stored.
	req, _ := http.NewRequest("GET", h.http.URL+"/api/v1/databases/"+db+"/blob", nil)
	req.Header.Set("Authorization", "Bearer "+tok)
	resp, err := h.http.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	got, _ := io.ReadAll(resp.Body)
	if string(got) != "kdbx-v1" || resp.Header.Get("ETag") != `"1"` {
		t.Fatalf("download = %q etag %q", got, resp.Header.Get("ETag"))
	}
}

func TestClientWinsAllowsForce(t *testing.T) {
	h := newHarness(t)
	tok, _, _ := h.login("admin", adminPassword, "")
	db := h.makeDB(tok, "Team")
	h.push(tok, db, `"0"`, []byte("v1"))

	if status, body := h.call("PATCH", "/api/v1/databases/"+db, tok,
		map[string]string{"merge_strategy": "client-wins"}); status != http.StatusOK {
		t.Fatalf("patch strategy: %d %v", status, body)
	}
	status, body, _ := h.push(tok, db, "*", []byte("v2-forced"))
	if status != http.StatusOK || body["version"].(float64) != 2 {
		t.Fatalf("forced push: %d %v", status, body)
	}
}

func TestReadOnlyGrantCannotPush(t *testing.T) {
	h := newHarness(t)
	admin, _, _ := h.login("admin", adminPassword, "")
	db := h.makeDB(admin, "Team")

	// A child group with a read-only grant, and a member invited into it.
	status, g := h.call("POST", "/api/v1/groups", admin,
		map[string]string{"name": "readers", "parent_id": "everyone"})
	if status != http.StatusCreated {
		t.Fatalf("create group: %d %v", status, g)
	}
	readers := g["id"].(string)
	if status, body := h.call("POST", "/api/v1/grants", admin, map[string]string{
		"group_id": readers, "database_id": db, "perm": "read"}); status != http.StatusOK {
		t.Fatalf("grant: %d %v", status, body)
	}
	status, inv := h.call("POST", "/api/v1/invites", admin,
		map[string]any{"group_id": readers, "role": "member", "ttl_hours": 1, "max_uses": 1})
	if status != http.StatusCreated {
		t.Fatalf("invite: %d %v", status, inv)
	}
	token := inv["token"].(string)

	form := url.Values{"username": {"reader"}, "password": {"reader-password"},
		"password2": {"reader-password"}}
	resp, err := h.http.Client().PostForm(h.http.URL+"/invite/"+token, form)
	if err != nil {
		t.Fatal(err)
	}
	page, _ := io.ReadAll(resp.Body)
	resp.Body.Close()
	if !strings.Contains(string(page), "Account created") {
		t.Fatalf("invite redemption page: %s", page)
	}

	rtok, status, _ := h.login("reader", "reader-password", "")
	if status != http.StatusOK {
		t.Fatalf("reader login: %d", status)
	}
	// The reader sees the database through the grant on its group...
	status, list := h.call("GET", "/api/v1/databases", rtok, nil)
	dbs := list["databases"].([]any)
	if status != http.StatusOK || len(dbs) != 1 {
		t.Fatalf("reader database list: %d %v", status, list)
	}
	if dbs[0].(map[string]any)["perm"] != "read" {
		t.Fatalf("reader perm = %v", dbs[0])
	}
	// ...but may not write it.
	if status, body, _ := h.push(rtok, db, `"0"`, []byte("nope")); status != http.StatusForbidden {
		t.Fatalf("reader push: %d %v", status, body)
	}
	// A second redemption of a single-use invite fails.
	resp2, err := h.http.Client().PostForm(h.http.URL+"/invite/"+token, form)
	if err != nil {
		t.Fatal(err)
	}
	page2, _ := io.ReadAll(resp2.Body)
	resp2.Body.Close()
	if !strings.Contains(string(page2), "already been used") {
		t.Fatalf("reused invite page: %s", page2)
	}
}

func TestEventStreamDeliversPush(t *testing.T) {
	h := newHarness(t)
	tok, _, _ := h.login("admin", adminPassword, "")
	db := h.makeDB(tok, "Team")

	req, _ := http.NewRequest("GET", h.http.URL+"/api/v1/events?access_token="+tok, nil)
	resp, err := h.http.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "text/event-stream") {
		t.Fatalf("content type = %q", ct)
	}

	lines := make(chan string, 8)
	go func() {
		sc := bufio.NewScanner(resp.Body)
		for sc.Scan() {
			lines <- sc.Text()
		}
		close(lines)
	}()
	// Wait for the stream to register before pushing.
	deadline := time.After(3 * time.Second)
	for h.srv.hub.Count() == 0 {
		select {
		case <-deadline:
			t.Fatal("stream never registered")
		default:
			time.Sleep(5 * time.Millisecond)
		}
	}
	if status, body, _ := h.push(tok, db, `"0"`, []byte("v1")); status != http.StatusOK {
		t.Fatalf("push: %d %v", status, body)
	}
	for {
		select {
		case l, open := <-lines:
			if !open {
				t.Fatal("stream closed before the event arrived")
			}
			if strings.HasPrefix(l, "data: ") {
				var ev Event
				if err := json.Unmarshal([]byte(strings.TrimPrefix(l, "data: ")), &ev); err != nil {
					t.Fatal(err)
				}
				if ev.Type != EventUpdated || ev.DatabaseID != db || ev.Version != 1 {
					t.Fatalf("event = %+v", ev)
				}
				return
			}
		case <-time.After(5 * time.Second):
			t.Fatal("timed out waiting for the push event")
		}
	}
}

func TestTOTPEnrollmentThenRequiredAtLogin(t *testing.T) {
	h := newHarness(t)
	tok, _, _ := h.login("admin", adminPassword, "")
	status, body := h.call("POST", "/api/v1/auth/totp/enroll", tok, nil)
	if status != http.StatusOK {
		t.Fatalf("enroll: %d %v", status, body)
	}
	sec := body["secret"].(string)
	if !strings.HasPrefix(body["uri"].(string), "otpauth://totp/") {
		t.Fatalf("uri = %v", body["uri"])
	}
	code, err := totp.Code(sec, time.Now())
	if err != nil {
		t.Fatal(err)
	}
	if status, body = h.call("POST", "/api/v1/auth/totp/confirm", tok,
		map[string]string{"code": code}); status != http.StatusOK {
		t.Fatalf("confirm: %d %v", status, body)
	}
	if _, status, body = h.login("admin", adminPassword, ""); status != http.StatusUnauthorized ||
		body["code"] != "totp_required" {
		t.Fatalf("login without code: %d %v", status, body)
	}
	code, _ = totp.Code(sec, time.Now())
	if _, status, body = h.login("admin", adminPassword, code); status != http.StatusOK {
		t.Fatalf("login with code: %d %v", status, body)
	}
}

func TestDeviceLoginApprovedInBrowser(t *testing.T) {
	h := newHarness(t)
	status, start := h.call("POST", "/api/v1/auth/device/start", "", map[string]string{"label": "laptop"})
	if status != http.StatusOK {
		t.Fatalf("device start: %d %v", status, start)
	}
	deviceCode := start["device_code"].(string)
	userCode := start["user_code"].(string)
	if !strings.Contains(start["verification_url"].(string), userCode) {
		t.Fatalf("verification url = %v", start["verification_url"])
	}
	if status, body := h.call("POST", "/api/v1/auth/device/poll", "",
		map[string]string{"device_code": deviceCode}); status != http.StatusAccepted {
		t.Fatalf("poll before approval: %d %v", status, body)
	}
	resp, err := h.http.Client().PostForm(h.http.URL+"/device", url.Values{
		"code": {userCode}, "username": {"admin"}, "password": {adminPassword}})
	if err != nil {
		t.Fatal(err)
	}
	page, _ := io.ReadAll(resp.Body)
	resp.Body.Close()
	if !strings.Contains(string(page), "Device approved") {
		t.Fatalf("approval page: %s", page)
	}
	status, body := h.call("POST", "/api/v1/auth/device/poll", "",
		map[string]string{"device_code": deviceCode})
	if status != http.StatusOK || body["token"] == "" {
		t.Fatalf("poll after approval: %d %v", status, body)
	}
	// The issued token works, and the device code is single use.
	if status, _ := h.call("GET", "/api/v1/auth/whoami", body["token"].(string), nil); status != http.StatusOK {
		t.Fatalf("whoami with device token: %d", status)
	}
	if status, _ := h.call("POST", "/api/v1/auth/device/poll", "",
		map[string]string{"device_code": deviceCode}); status != http.StatusGone {
		t.Fatalf("second poll: %d", status)
	}
}

func TestNonAdminCannotAdminister(t *testing.T) {
	h := newHarness(t)
	admin, _, _ := h.login("admin", adminPassword, "")
	hash, _ := secret.Hash("outsider-password")
	if err := h.srv.Store().Update(func(st *store.State) error {
		st.Users["out"] = &store.User{ID: "out", Username: "outsider", PassHash: hash}
		return nil
	}); err != nil {
		t.Fatal(err)
	}
	db := h.makeDB(admin, "Team")
	otok, _, _ := h.login("outsider", "outsider-password", "")

	if status, _ := h.call("POST", "/api/v1/databases", otok,
		map[string]string{"name": "x", "owner_group_id": "everyone"}); status != http.StatusForbidden {
		t.Fatalf("outsider created a database: %d", status)
	}
	if status, _ := h.call("PATCH", "/api/v1/databases/"+db, otok,
		map[string]string{"merge_strategy": "client-wins"}); status != http.StatusForbidden {
		t.Fatalf("outsider changed the strategy: %d", status)
	}
	// Without any grant the database is invisible, not merely unwritable.
	if status, _ := h.call("GET", "/api/v1/databases/"+db+"/blob", otok, nil); status != http.StatusNotFound {
		t.Fatalf("outsider read the blob: %d", status)
	}
	if status, _ := h.call("GET", "/api/v1/databases", "", nil); status != http.StatusUnauthorized {
		t.Fatalf("anonymous list: %d", status)
	}
}