package main

import (
	"context"
	"io"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/audit"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/auth"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/config"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/httpx"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/setup"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/store"
	"git.lohmar.co.uk/cclohmar/NextMyDay/internal/core/users"
)

// stubEnroller satisfies setup.Enroller — this test never runs a ceremony.
type stubEnroller struct{}

func (stubEnroller) TOTPBegin(http.ResponseWriter, *http.Request, string) error  { return nil }
func (stubEnroller) TOTPVerify(http.ResponseWriter, *http.Request, string) error { return nil }

// setupYAML is a fresh-instance config: setup mode, every secret a placeholder.
const setupYAML = `setup: true
server:
  listen: "127.0.0.1:8080"
  base_url: "https://myday.example.com"
app:
  locale: "en-GB"
database:
  path: "DBPATH"
secrets:
  cookie_secret: "CHANGE_ME_32_BYTES_RANDOM"
  csrf_key: "CHANGE_ME_32_BYTES_RANDOM"
  totp_encryption_key: "CHANGE_ME_32_BYTES_RANDOM"
`

// TestTOTPKeySurvivesSetupAndRestart pins the D-1 invariant (M2c): the TOTP key
// the process GENERATES AT STARTUP is the key the wizard persists, so a restart
// adopts the same key and the secrets enrolled during setup still unseal. A
// regression here silently destroys every future TOTP secret.
func TestTOTPKeySurvivesSetupAndRestart(t *testing.T) {
	ctx := context.Background()
	dir := t.TempDir()
	cfgPath := filepath.Join(dir, config.FileName)
	dbPath := filepath.Join(dir, "myday.db")
	body := strings.Replace(setupYAML, "DBPATH", dbPath, 1)
	if err := os.WriteFile(cfgPath, []byte(body), 0o600); err != nil {
		t.Fatalf("write config: %v", err)
	}

	cfg, err := config.Load(cfgPath)
	if err != nil {
		t.Fatalf("config.Load: %v", err)
	}

	// Startup (D-1 + M1s): every placeholder is replaced with a strong value
	// the PROCESS will use — the wizard's ceremony must not run on a shipped
	// placeholder key.
	key, generated, err := prepareTOTPKey(cfg)
	if err != nil {
		t.Fatalf("prepareTOTPKey: %v", err)
	}
	if !generated || config.SecretIsPlaceholder(key) || len(key) != auth.KeySize {
		t.Fatalf("the TOTP key was not generated (generated=%v len=%d)", generated, len(key))
	}
	cfg.Secrets.TOTPEncryptionKey = key // run() adopts it in setup mode
	if _, err := prepareSigningKeys(cfg); err != nil {
		t.Fatalf("prepareSigningKeys: %v", err)
	}

	// First run: the wizard enrolls the admin and seals its TOTP secret with
	// the startup key.
	db, err := store.Open(cfg.Database.Path)
	if err != nil {
		t.Fatalf("store.Open: %v", err)
	}
	if err := db.Migrate(); err != nil {
		t.Fatalf("Migrate: %v", err)
	}
	aud := audit.New(db.DB)
	us := users.New(db.DB, aud)
	if _, err := us.Create(ctx, 0, "admin@example.com", "Claus", users.RoleAdmin); err != nil {
		t.Fatalf("create admin: %v", err)
	}
	sealer, err := auth.NewAEADSealer([]byte(key))
	if err != nil {
		t.Fatalf("NewAEADSealer: %v", err)
	}
	ids := auth.New(db.DB, aud, auth.WithSealer(sealer)).Identities()
	idID, _, err := ids.Mint(ctx, 1)
	if err != nil {
		t.Fatalf("Mint: %v", err)
	}
	if err := ids.Activate(ctx, idID); err != nil {
		t.Fatalf("Activate: %v", err)
	}
	const secret = "JBSWY3DPEHPK3PXP"
	if err := ids.PutTOTPSecret(ctx, idID, []byte(secret)); err != nil {
		t.Fatalf("PutTOTPSecret: %v", err)
	}

	// The wizard persists the config (`finish`).
	pre, err := httpx.NewPreSessionCSRF([]byte(cfg.Secrets.CookieSecret), false)
	if err != nil {
		t.Fatalf("NewPreSessionCSRF: %v", err)
	}
	wiz, err := setup.New(setup.Deps{
		Config: cfg, ConfigPath: cfgPath, Users: us, Identities: ids,
		Enroll: stubEnroller{}, CSRF: pre, Audit: aud, Printout: io.Discard,
	})
	if err != nil {
		t.Fatalf("setup.New: %v", err)
	}
	form := url.Values{"app.locale": {"en-GB"}, "app.timezone": {"Europe/London"}}
	req := httptest.NewRequest("POST", "/setup?do=setup&action=finish", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	if err := wiz.Finish(rec, req); err != nil {
		t.Fatalf("Finish: %v", err)
	}
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("Finish = %d, want 303", rec.Code)
	}
	if err := db.Close(); err != nil {
		t.Fatalf("close db: %v", err)
	}

	// Restart: the persisted config must carry the SAME TOTP key, and the
	// sealed secret must still open with it (D-1 — the whole point).
	restored, err := config.Load(cfgPath)
	if err != nil {
		t.Fatalf("the persisted config does not load after setup: %v", err)
	}
	if restored.Setup {
		t.Error("the persisted config still says setup: true")
	}
	if restored.Secrets.TOTPEncryptionKey != key {
		t.Fatalf("the persisted TOTP key differs from the runtime key (D-1):\n got %q\nwant %q",
			restored.Secrets.TOTPEncryptionKey, key)
	}

	db2, err := store.Open(restored.Database.Path)
	if err != nil {
		t.Fatalf("reopen db: %v", err)
	}
	defer func() { _ = db2.Close() }()
	sealer2, err := auth.NewAEADSealer([]byte(restored.Secrets.TOTPEncryptionKey))
	if err != nil {
		t.Fatalf("restart sealer: %v", err)
	}
	ids2 := auth.New(db2.DB, nil, auth.WithSealer(sealer2)).Identities()
	got, err := ids2.TOTPSecret(ctx, idID)
	if err != nil {
		t.Fatalf("the TOTP secret no longer unseals after a restart (D-1/M2c): %v", err)
	}
	if string(got) != secret {
		t.Errorf("TOTP secret after restart = %q, want %q", got, secret)
	}
}