package stacks

import (
	"encoding/json"
	"io"
	"log"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"sync"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/crypto"
	"gitea.dooplex.hu/admin/felhom-controller/internal/settings"
)

// R-513 — FileBrowser accepted admin/admin on every box. The fake below behaves like the measured
// Quantum 1.3.3 API (evidence-p1fixes-2026-09-15/B1): login by X-Password, PUT /api/users with the
// current password in X-Password.

type fakeFB struct {
	mu       sync.Mutex
	password string
	puts     int
}

func (f *fakeFB) handler() http.Handler {
	mux := http.NewServeMux()
	mux.HandleFunc("/api/auth/login", func(w http.ResponseWriter, r *http.Request) {
		f.mu.Lock()
		defer f.mu.Unlock()
		if r.Header.Get("X-Password") != f.password {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}
		io.WriteString(w, "tok-123")
	})
	mux.HandleFunc("/api/users", func(w http.ResponseWriter, r *http.Request) {
		f.mu.Lock()
		defer f.mu.Unlock()
		if r.Header.Get("X-Auth") != "tok-123" {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}
		switch r.Method {
		case http.MethodGet:
			io.WriteString(w, `{"id":1,"username":"admin"}`)
		case http.MethodPut:
			if r.Header.Get("X-Password") != f.password {
				w.WriteHeader(http.StatusUnauthorized)
				return
			}
			var body struct {
				Which []string `json:"which"`
				Data  struct {
					Password string `json:"password"`
				} `json:"data"`
			}
			_ = json.NewDecoder(r.Body).Decode(&body)
			f.password = body.Data.Password
			f.puts++
			w.WriteHeader(http.StatusNoContent)
		}
	})
	return mux
}

func fbManager(t *testing.T, base string) (*Manager, *settings.Settings, []byte) {
	t.Helper()
	st, err := settings.Load(filepath.Join(t.TempDir(), "settings.json"), log.New(io.Discard, "", 0))
	if err != nil {
		t.Fatal(err)
	}
	key := make([]byte, 32)
	for i := range key {
		key[i] = byte(i + 1)
	}
	return &Manager{logger: log.New(io.Discard, "", 0), settings: st, encKey: key, fbBaseURL: base}, st, key
}

// The consequence: after one tick admin/admin no longer logs in, the stored (decrypted) password
// does, and the state is "generated". A second tick changes nothing.
//
// RED-PROOF (run 2026-09-15, recorded in REPORT.md): with EnsureFileBrowserAdminPassword returning
// nil before the PUT, admin/admin stayed valid and this failed at "admin/admin still logs in".
func TestFileBrowserAdmin_DefaultLoginReplaced(t *testing.T) {
	fb := &fakeFB{password: "admin"}
	srv := httptest.NewServer(fb.handler())
	defer srv.Close()
	m, st, key := fbManager(t, srv.URL)

	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
		t.Fatalf("ensure: %v", err)
	}
	if _, c, _ := fbLogin(srv.Client().Do, srv.URL, "admin"); c == http.StatusOK {
		t.Fatalf("admin/admin still logs in — R-513 not fixed")
	}
	state, enc, at := st.GetFileBrowserAdmin()
	if state != settings.FileBrowserAdminGenerated || enc == "" || at == "" {
		t.Fatalf("decision not recorded: state=%q enc=%v at=%q", state, enc != "", at)
	}
	if enc == fb.password {
		t.Fatal("the password was stored in plaintext")
	}
	pw, err := crypto.Decrypt(key, enc)
	if err != nil || len(pw) != 16 {
		t.Fatalf("stored password does not decrypt to a 16-char value (len=%d err=%v)", len(pw), err)
	}
	if _, c, _ := fbLogin(srv.Client().Do, srv.URL, pw); c != http.StatusOK {
		t.Fatalf("the stored password does not log in (HTTP %d)", c)
	}
	_ = m.EnsureFileBrowserAdminPassword()
	if fb.puts != 1 {
		t.Fatalf("a recorded decision was acted on again (puts=%d)", fb.puts)
	}
}

// A password set by hand (admin/admin refused) is NEVER overwritten.
func TestFileBrowserAdmin_HandSetPasswordLeftAlone(t *testing.T) {
	fb := &fakeFB{password: "operator-set-by-hand"}
	srv := httptest.NewServer(fb.handler())
	defer srv.Close()
	m, st, _ := fbManager(t, srv.URL)
	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
		t.Fatal(err)
	}
	if fb.puts != 0 || fb.password != "operator-set-by-hand" {
		t.Fatalf("hand-set password was changed (puts=%d)", fb.puts)
	}
	if state, enc, _ := st.GetFileBrowserAdmin(); state != settings.FileBrowserAdminOperator || enc != "" {
		t.Fatalf("want state operator with no stored value, got %q enc=%v", state, enc != "")
	}
}

// FileBrowser not reachable → nothing recorded, so the next tick tries again.
func TestFileBrowserAdmin_UnreachableRecordsNothing(t *testing.T) {
	srv := httptest.NewServer(http.NotFoundHandler())
	url := srv.URL
	srv.Close()
	m, st, _ := fbManager(t, url)
	if err := m.EnsureFileBrowserAdminPassword(); err == nil {
		t.Fatal("want an error (for the log) when FileBrowser is unreachable")
	}
	if state, _, _ := st.GetFileBrowserAdmin(); state != "" {
		t.Fatalf("an unreachable FileBrowser recorded a decision: %q", state)
	}
}

// R-977: the decision is no longer once per box. A FileBrowser whose data was re-created (a new run whose database
// starts on admin/admin again) is reset at its first tick; the same run is never probed twice; a new run on another
// password (the household's own) leaves the recorded decision alone.
//
// RED-PROOF (2026-10-17): with the old early return (`if state != "" { return nil }`) the second run keeps
// admin/admin and this fails at „the default login came back on a new run and was left".
func TestFileBrowserAdmin_R977_DefaultBackOnANewRunIsReplaced(t *testing.T) {
	fb := &fakeFB{password: "admin"}
	srv := httptest.NewServer(fb.handler())
	defer srv.Close()
	m, st, key := fbManager(t, srv.URL)
	run := "2026-10-17T06:54:56Z"
	m.fbStarted = func() string { return run }

	if err := m.EnsureFileBrowserAdminPassword(); err != nil { // first run: a new box
		t.Fatal(err)
	}
	_, enc1, _ := st.GetFileBrowserAdmin()

	// The data volume is re-created: FileBrowser starts again on its default.
	fb.mu.Lock()
	fb.password = "admin"
	fb.mu.Unlock()
	if err := m.EnsureFileBrowserAdminPassword(); err != nil { // the SAME run: not probed again
		t.Fatal(err)
	}
	if fb.puts != 1 {
		t.Fatalf("the same FileBrowser run was probed and changed again (puts=%d)", fb.puts)
	}
	run = "2026-10-17T09:12:00Z" // the box brought FileBrowser back: a new run
	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
		t.Fatal(err)
	}
	if _, c, _ := fbLogin(srv.Client().Do, srv.URL, "admin"); c == http.StatusOK {
		t.Fatal("the default login came back on a new run and was left")
	}
	state, enc2, _ := st.GetFileBrowserAdmin()
	if state != settings.FileBrowserAdminGenerated || enc2 == "" || enc2 == enc1 {
		t.Fatalf("a new generated password must be recorded: state=%q changed=%v", state, enc2 != enc1)
	}
	pw, err := crypto.Decrypt(key, enc2)
	if err != nil {
		t.Fatal(err)
	}
	if _, c, _ := fbLogin(srv.Client().Do, srv.URL, pw); c != http.StatusOK {
		t.Fatalf("the recorded password does not log in (HTTP %d)", c)
	}

	// The household changes it in FileBrowser; a later run on THEIR password changes nothing.
	fb.mu.Lock()
	fb.password = "the-households-own"
	fb.mu.Unlock()
	run = "2026-10-18T02:30:00Z"
	puts := fb.puts
	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
		t.Fatal(err)
	}
	if fb.puts != puts || fb.password != "the-households-own" {
		t.Fatalf("a run on the household's own password was changed (puts %d -> %d)", puts, fb.puts)
	}
	if s, e, _ := st.GetFileBrowserAdmin(); s != settings.FileBrowserAdminGenerated || e != enc2 {
		t.Fatalf("the recorded decision moved on a run that is not on the default: state=%q", s)
	}
}

// R-977, measured live: the tick that brings FileBrowser back probes it while it is still starting, and without a wait
// the default login stayed open until the next round (5 minutes on 9202). A NEW run is given a short wait.
// RED-PROOF (2026-10-17): with one try per tick this fails at „the default stayed open".
func TestFileBrowserAdmin_R977_NewRunIsWaitedForInTheSameTick(t *testing.T) {
	fb := &fakeFB{password: "admin"}
	starting := 3 // the first three answers: FileBrowser not ready yet
	inner := fb.handler()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fb.mu.Lock()
		notReady := starting > 0
		if notReady {
			starting--
		}
		fb.mu.Unlock()
		if notReady {
			w.WriteHeader(http.StatusBadGateway)
			return
		}
		inner.ServeHTTP(w, r)
	}))
	defer srv.Close()
	m, st, _ := fbManager(t, srv.URL)
	m.fbStarted = func() string { return "2026-10-17T09:24:35Z" }
	if err := m.EnsureFileBrowserAdminPassword(); err != nil {
		t.Fatalf("one tick: %v", err)
	}
	if _, c, _ := fbLogin(srv.Client().Do, srv.URL, "admin"); c == http.StatusOK {
		t.Fatal("the default stayed open after the tick that started FileBrowser")
	}
	if s, _, _ := st.GetFileBrowserAdmin(); s != settings.FileBrowserAdminGenerated {
		t.Fatalf("state %q, want generated", s)
	}
}