package retentiondestroy

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"
	"time"

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

	"gitea.perlbach24.de/scripte/nexarch/dms/internal/jobqueue"
	"gitea.perlbach24.de/scripte/nexarch/dms/internal/retentionclient"
	"gitea.perlbach24.de/scripte/nexarch/dms/internal/storage"
)

func setupTest(t *testing.T) *pgxpool.Pool {
	t.Helper()
	dsn := os.Getenv("TEST_TENANT_DSN")
	if dsn == "" {
		t.Skip("TEST_TENANT_DSN nicht gesetzt, Integrationstest uebersprungen")
	}
	ctx := context.Background()
	pool, err := pgxpool.New(ctx, dsn)
	if err != nil {
		t.Fatalf("pool: %v", err)
	}
	t.Cleanup(func() { pool.Close() })

	if _, err := pool.Exec(ctx, `
		CREATE EXTENSION IF NOT EXISTS pgcrypto;
		CREATE TABLE IF NOT EXISTS users (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(), email TEXT NOT NULL UNIQUE, name TEXT NOT NULL DEFAULT 'Test'
		);
		CREATE TABLE IF NOT EXISTS documents (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			folder_id UUID,
			title TEXT NOT NULL,
			current_revision_id UUID,
			created_by UUID NOT NULL REFERENCES users(id),
			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
			updated_at TIMESTAMPTZ NOT NULL DEFAULT now(),
			deleted_at TIMESTAMPTZ
		);
		CREATE TABLE IF NOT EXISTS file_revisions (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			document_id UUID NOT NULL REFERENCES documents(id) ON DELETE CASCADE,
			revision_number INT NOT NULL,
			storage_key TEXT NOT NULL,
			checksum_sha256 TEXT NOT NULL,
			size_bytes BIGINT NOT NULL,
			mime_type TEXT NOT NULL,
			created_by UUID NOT NULL REFERENCES users(id),
			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
			UNIQUE (document_id, revision_number)
		);
		CREATE TABLE IF NOT EXISTS processing_jobs (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(), job_type TEXT NOT NULL,
			payload JSONB NOT NULL DEFAULT '{}'::jsonb, idempotency_key TEXT UNIQUE,
			status TEXT NOT NULL DEFAULT 'pending' CHECK (status IN ('pending', 'processing', 'succeeded', 'failed', 'dead_letter')),
			attempts INT NOT NULL DEFAULT 0, max_attempts INT NOT NULL DEFAULT 5,
			available_at TIMESTAMPTZ NOT NULL DEFAULT now(), locked_at TIMESTAMPTZ, locked_by TEXT,
			last_error TEXT, created_at TIMESTAMPTZ NOT NULL DEFAULT now(), updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
		);
	`); err != nil {
		t.Fatalf("schema: %v", err)
	}
	t.Cleanup(func() {
		_, _ = pool.Exec(context.Background(), `TRUNCATE processing_jobs, file_revisions, documents, users CASCADE`)
	})
	return pool
}

type fakeUsageReporter struct{ reports []int64 }

func (f *fakeUsageReporter) Report(ctx context.Context, tenantSlug, metric string, delta int64) error {
	f.reports = append(f.reports, delta)
	return nil
}

// fakeRET05Server simuliert Archive RET-05/RET-09 (POST /register).
func fakeRET05Server(t *testing.T, fail bool) *retentionclient.Client {
	t.Helper()
	mux := http.NewServeMux()
	mux.HandleFunc("POST /register", func(w http.ResponseWriter, r *http.Request) {
		if fail {
			http.Error(w, "simulierter fehler", http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(map[string]string{
			"ID": "fake-reg-id", "ModuleName": ModuleName, "ObjectType": ObjectTypeDocument,
			"RetentionClass": "test-klasse", "CallbackURL": "http://test/callback",
		})
	})
	server := httptest.NewServer(mux)
	t.Cleanup(server.Close)
	return retentionclient.New(server.URL)
}

// TestRegisterOrRequeue_RealRegistrationAgainstTestEndpoint ist die
// geforderte Pflichtpruefung 1: Registrierung real gegen einen
// Test-RET-05-Endpunkt durchgefuehrt und verifiziert.
func TestRegisterOrRequeue_RealRegistrationAgainstTestEndpoint(t *testing.T) {
	pool := setupTest(t)
	client := fakeRET05Server(t, false)
	queue := jobqueue.NewQueue(pool, time.Minute)

	queued, err := RegisterOrRequeue(context.Background(), client, queue, RegisterConfig{
		ObjectType: ObjectTypeDocument, RetentionClass: "test-klasse", CallbackURL: "http://test/callback",
	})
	if err != nil {
		t.Fatalf("erwartet erfolgreiche registrierung, habe fehler: %v", err)
	}
	if queued {
		t.Fatal("erfolgreiche registrierung haette NICHT requeued werden duerfen")
	}
}

// TestDestroyCallbackHandler_RealDeletionAnd2xx ist die geforderte
// Pflichtpruefung 2: Vernichtungs-Rueckruf gegen einen echten Testfall
// ausgeloest, DMS-Loeschung nachweislich erfolgt, 2xx-Antwort gesendet.
func TestDestroyCallbackHandler_RealDeletionAnd2xx(t *testing.T) {
	pool := setupTest(t)
	ctx := context.Background()

	var userID string
	if err := pool.QueryRow(ctx, `INSERT INTO users (email, name) VALUES ('destroy-test@acme.example', 'Destroy Test') RETURNING id`).Scan(&userID); err != nil {
		t.Fatal(err)
	}
	var docID string
	if err := pool.QueryRow(ctx, `INSERT INTO documents (title, created_by) VALUES ('Zu vernichtendes Dokument', $1) RETURNING id`, userID).Scan(&docID); err != nil {
		t.Fatal(err)
	}

	storageDir := t.TempDir()
	driver := storage.NewLocalDriver(storageDir, []byte("secret"), "https://files.example.test")
	usage := &fakeUsageReporter{}
	storageSvc := storage.NewService(driver, usage, "acme")

	storageKey := "documents/" + docID + "/revisions/rev-1"
	content := "vertrauliches dokument"
	if _, err := storageSvc.Put(ctx, storageKey, strings.NewReader(content), int64(len(content)), "text/plain"); err != nil {
		t.Fatalf("testdatei ablegen: %v", err)
	}
	if _, err := pool.Exec(ctx, `
		INSERT INTO file_revisions (document_id, revision_number, storage_key, checksum_sha256, size_bytes, mime_type, created_by)
		VALUES ($1, 1, $2, 'irrelevant', $3, 'text/plain', $4)
	`, docID, storageKey, len(content), userID); err != nil {
		t.Fatal(err)
	}

	handler := DestroyCallbackHandler(pool, storageSvc)
	server := httptest.NewServer(handler)
	defer server.Close()

	body, _ := json.Marshal(destroyRequest{
		ObjectType: ObjectTypeDocument, ObjectReference: docID, DestroyedAt: time.Now().UTC().Format(time.RFC3339),
	})
	resp, err := http.Post(server.URL, "application/json", strings.NewReader(string(body)))
	if err != nil {
		t.Fatalf("post: %v", err)
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		t.Fatalf("status = %d, want 2xx", resp.StatusCode)
	}

	// Nachweis: Storage-Objekt WIRKLICH geloescht (nicht nur DB-Flag).
	if _, err := driver.Get(ctx, storageKey); err == nil {
		t.Fatal("erwartet geloeschtes storage-objekt, konnte es aber noch lesen")
	}

	var deletedAt *time.Time
	if err := pool.QueryRow(ctx, `SELECT deleted_at FROM documents WHERE id = $1`, docID).Scan(&deletedAt); err != nil {
		t.Fatal(err)
	}
	if deletedAt == nil {
		t.Fatal("erwartet gesetztes deleted_at nach vernichtung")
	}
	if len(usage.reports) != 2 || usage.reports[0] <= 0 || usage.reports[1] >= 0 {
		t.Fatalf("erwartet eine positive (put) und eine negative (delete) nutzungsmeldung, habe: %v", usage.reports)
	}
}

// TestRegisterOrRequeue_FailedRegistrationCreatesRequeueEntry ist die
// geforderte Pflichtpruefung 3: simulierter Nicht-2xx-Fehler bei der
// Registrierung fuehrt nachweislich zu einem Requeue-Eintrag in der
// Jobqueue, kein Absturz.
func TestRegisterOrRequeue_FailedRegistrationCreatesRequeueEntry(t *testing.T) {
	pool := setupTest(t)
	client := fakeRET05Server(t, true)
	queue := jobqueue.NewQueue(pool, time.Minute)

	queued, err := RegisterOrRequeue(context.Background(), client, queue, RegisterConfig{
		ObjectType: ObjectTypeDocument, RetentionClass: "test-klasse", CallbackURL: "http://test/callback",
	})
	if err == nil {
		t.Fatal("erwartet fehler von der fehlgeschlagenen registrierung (fuer protokollierung), habe nil")
	}
	if !queued {
		t.Fatal("erwartet queued=true bei fehlgeschlagener registrierung")
	}

	var count int
	if err := pool.QueryRow(context.Background(), `SELECT count(*) FROM processing_jobs WHERE job_type = $1 AND status = 'pending'`, JobTypeRegister).Scan(&count); err != nil {
		t.Fatal(err)
	}
	if count != 1 {
		t.Fatalf("erwartet genau einen requeue-eintrag in der jobqueue, habe %d", count)
	}
}

// TestProcessRegisterJob_SucceedsOnRetry beweist, dass ein Requeue-Job
// vom Worker erfolgreich nachgeholt werden kann (Requeue ist kein
// Sackgassen-Zustand).
func TestProcessRegisterJob_SucceedsOnRetry(t *testing.T) {
	setupTest(t)
	client := fakeRET05Server(t, false)
	payload, _ := json.Marshal(RegisterConfig{ObjectType: ObjectTypeDocument, RetentionClass: "test-klasse", CallbackURL: "http://test/callback"})

	if err := ProcessRegisterJob(context.Background(), client, payload); err != nil {
		t.Fatalf("erwartet erfolgreichen retry, habe fehler: %v", err)
	}
}