package tenant

import (
	"context"
	"errors"
	"os"
	"strings"
	"sync"
	"testing"

	"github.com/jackc/pgx/v5/pgxpool"

	"gitea.perlbach24.de/scripte/nexarch/internal/user"
)

// schemaPathForTest liefert den Pfad zur echten Migration, damit Tests exakt
// dasselbe Schema anwenden wie die Produktion (keine Zweitkopie des SQL).
const schemaPathForTest = "../../migrations/tenant/0001_users.up.sql"

func TestOnboarding_ValidationErrors(t *testing.T) {
	// Reine Eingabevalidierung, braucht keine Datenbank.
	svc := NewOnboardingService(nil, schemaPathForTest)
	ctx := context.Background()

	cases := []struct {
		name       string
		slug       string
		tenantName string
		email      string
		adminName  string
		wantErr    error
	}{
		{"leerer name", "acme", "", "a@b.de", "Admin", ErrMissingField},
		{"leerer admin-name", "acme", "Acme", "a@b.de", "", ErrMissingField},
		{"ungueltiger slug", "Acme!", "Acme", "a@b.de", "Admin", ErrInvalidSlug},
		{"ungueltige email", "acme", "Acme", "keine-email", "Admin", user.ErrInvalidEmail},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			_, err := svc.Onboard(ctx, c.slug, c.tenantName, c.email, c.adminName)
			if !errors.Is(err, c.wantErr) {
				t.Fatalf("erwartet %v, habe %v", c.wantErr, err)
			}
		})
	}
}

func newTestOnboardingService(t *testing.T) (*OnboardingService, func()) {
	t.Helper()
	adminDSN := os.Getenv("TEST_ADMIN_DSN")
	if adminDSN == "" {
		t.Skip("TEST_ADMIN_DSN nicht gesetzt, Integrationstest uebersprungen")
	}
	ctx := context.Background()

	adminPool, err := pgxpool.New(ctx, adminDSN)
	if err != nil {
		t.Fatalf("admin pool: %v", err)
	}
	registryPool, err := pgxpool.New(ctx, adminDSN)
	if err != nil {
		t.Fatalf("registry pool: %v", err)
	}

	if _, err := registryPool.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS tenants (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			slug TEXT NOT NULL UNIQUE,
			name TEXT NOT NULL,
			db_name TEXT NOT NULL UNIQUE,
			db_dsn TEXT NOT NULL,
			status TEXT NOT NULL DEFAULT 'active',
			created_at TIMESTAMPTZ NOT NULL DEFAULT now()
		)`); err != nil {
		t.Fatalf("registry-schema: %v", err)
	}

	registry := NewRegistry(registryPool)
	dsnTemplate := strings.Replace(adminDSN, "/postgres?", "/%s?", 1)
	provisioner := NewProvisioner(adminPool, registry, dsnTemplate)
	svc := NewOnboardingService(provisioner, schemaPathForTest)

	cleanup := func() {
		registryPool.Close()
		adminPool.Close()
	}
	return svc, cleanup
}

// Akzeptanzkriterien 1+2: Mandant + Erst-Admin in einem Vorgang.
func TestOnboarding_CreatesTenantAndAdmin(t *testing.T) {
	svc, cleanup := newTestOnboardingService(t)
	defer cleanup()
	ctx := context.Background()

	t.Cleanup(func() {
		adminDSN := os.Getenv("TEST_ADMIN_DSN")
		p, _ := pgxpool.New(ctx, adminDSN)
		defer p.Close()
		_, _ = p.Exec(ctx, `DELETE FROM tenants WHERE slug = 'onboardtest'`)
		_, _ = p.Exec(ctx, `DROP DATABASE IF EXISTS tenant_onboardtest`)
	})

	result, err := svc.Onboard(ctx, "onboardtest", "Onboard Test GmbH", "admin@onboardtest.example", "Erste Admin")
	if err != nil {
		t.Fatalf("onboard: %v", err)
	}
	if result.Tenant.Slug != "onboardtest" {
		t.Fatalf("tenant slug = %q", result.Tenant.Slug)
	}
	if result.Admin.Email != "admin@onboardtest.example" {
		t.Fatalf("admin email = %q", result.Admin.Email)
	}

	pool, err := pgxpool.New(ctx, result.Tenant.DBDSN)
	if err != nil {
		t.Fatalf("connect tenant db: %v", err)
	}
	defer pool.Close()

	var count int
	if err := pool.QueryRow(ctx, `SELECT count(*) FROM users WHERE email = $1`, "admin@onboardtest.example").Scan(&count); err != nil {
		t.Fatalf("admin in tenant-db pruefen: %v", err)
	}
	if count != 1 {
		t.Fatalf("erwartet genau einen admin in der tenant-db, habe %d", count)
	}
}

// Akzeptanzkriterium 3 + Pruefung 1: doppelte Registrierung wird abgewiesen,
// auch bei zwei parallelen Anfragen entsteht kein Doppel-Tenant.
func TestOnboarding_RejectsDuplicateSlugConcurrently(t *testing.T) {
	svc, cleanup := newTestOnboardingService(t)
	defer cleanup()
	ctx := context.Background()

	t.Cleanup(func() {
		adminDSN := os.Getenv("TEST_ADMIN_DSN")
		p, _ := pgxpool.New(ctx, adminDSN)
		defer p.Close()
		_, _ = p.Exec(ctx, `DELETE FROM tenants WHERE slug = 'dupetest'`)
		_, _ = p.Exec(ctx, `DROP DATABASE IF EXISTS tenant_dupetest`)
	})

	var wg sync.WaitGroup
	results := make([]error, 2)
	for i := 0; i < 2; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			_, err := svc.Onboard(ctx, "dupetest", "Dupe Test", "admin@dupetest.example", "Admin")
			results[i] = err
		}(i)
	}
	wg.Wait()

	successCount := 0
	for _, err := range results {
		if err == nil {
			successCount++
		} else if !errors.Is(err, ErrTenantExists) {
			t.Fatalf("unerwarteter fehler: %v", err)
		}
	}
	if successCount != 1 {
		t.Fatalf("erwartet genau einen erfolgreichen onboarding-vorgang, habe %d", successCount)
	}
}