package audit_test

import (
	"bufio"
	"context"
	"encoding/json"
	"log/slog"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/jackc/pgx/v5"

	"archivmail/internal/audit"
)

// testDSN returns a schema-scoped DSN for an isolated audit_log table, or skips
// the test if no PostgreSQL is configured.
func testDSN(t *testing.T) (dsn, schemaDSN string) {
	t.Helper()
	dsn = os.Getenv("TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("TEST_DATABASE_URL not set — skipping (needs PostgreSQL)")
	}
	schema := "autest_" + strings.ToLower(strings.ReplaceAll(t.Name(), "/", "_"))
	if len(schema) > 63 {
		schema = schema[:63]
	}
	ctx := context.Background()
	conn, err := pgx.Connect(ctx, dsn)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	conn.Exec(ctx, "CREATE SCHEMA IF NOT EXISTS "+schema)
	conn.Close(ctx)
	t.Cleanup(func() {
		conn2, _ := pgx.Connect(context.Background(), dsn)
		if conn2 != nil {
			conn2.Exec(context.Background(), "DROP SCHEMA "+schema+" CASCADE")
			conn2.Close(context.Background())
		}
	})
	sep := "?"
	if strings.Contains(dsn, "?") {
		sep = "&"
	}
	return dsn, dsn + sep + "search_path=" + schema
}

func newTestAudit(t *testing.T) *audit.Logger {
	t.Helper()
	dsn := os.Getenv("TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("TEST_DATABASE_URL not set — skipping (needs PostgreSQL)")
	}
	schema := "autest_" + strings.ToLower(strings.ReplaceAll(t.Name(), "/", "_"))
	// truncate schema name to 63 chars (PostgreSQL limit)
	if len(schema) > 63 {
		schema = schema[:63]
	}

	ctx := context.Background()
	conn, err := pgx.Connect(ctx, dsn)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	conn.Exec(ctx, "CREATE SCHEMA IF NOT EXISTS "+schema)
	conn.Close(ctx)

	sep := "?"
	if strings.Contains(dsn, "?") {
		sep = "&"
	}
	schemaDSN := dsn + sep + "search_path=" + schema

	logger := slog.New(slog.NewTextHandler(os.Discard, nil))
	l, err := audit.New(schemaDSN, t.TempDir(), logger)
	if err != nil {
		t.Fatalf("audit.New: %v", err)
	}
	t.Cleanup(func() {
		l.Close()
		conn2, _ := pgx.Connect(context.Background(), dsn)
		if conn2 != nil {
			conn2.Exec(context.Background(), "DROP SCHEMA "+schema+" CASCADE")
			conn2.Close(context.Background())
		}
	})
	return l
}

func TestLogAndQuery(t *testing.T) {
	l := newTestAudit(t)

	l.Log(audit.Entry{
		EventType: audit.EventLogin,
		Username:  "alice",
		IPAddress: "192.168.1.1",
		Success:   true,
	})
	l.Log(audit.Entry{
		EventType: audit.EventSearch,
		Username:  "alice",
		IPAddress: "192.168.1.1",
		Query:     "invoice",
		Success:   true,
	})
	l.Log(audit.Entry{
		EventType: audit.EventLogin,
		Username:  "bob",
		IPAddress: "10.0.0.1",
		Success:   false,
		Detail:    "wrong password",
	})

	all, total, err := l.Query(audit.QueryFilter{PageSize: 50})
	if err != nil {
		t.Fatalf("Query all: %v", err)
	}
	if total != 3 {
		t.Errorf("expected 3 entries, got %d", total)
	}
	_ = all
}

func TestQueryByUsername(t *testing.T) {
	l := newTestAudit(t)

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", Success: true})
	l.Log(audit.Entry{EventType: audit.EventSearch, Username: "alice", Success: true})
	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "bob", Success: true})

	entries, total, _ := l.Query(audit.QueryFilter{Username: "alice", PageSize: 50})
	if total != 2 {
		t.Errorf("alice: expected 2 entries, got %d", total)
	}
	for _, e := range entries {
		if e.Username != "alice" {
			t.Errorf("got entry for user %q in alice filter", e.Username)
		}
	}
}

func TestQueryByEventType(t *testing.T) {
	l := newTestAudit(t)

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", Success: true})
	l.Log(audit.Entry{EventType: audit.EventSearch, Username: "alice", Success: true})
	l.Log(audit.Entry{EventType: audit.EventMailView, Username: "alice", MailID: "abc123", Success: true})

	_, total, _ := l.Query(audit.QueryFilter{EventType: audit.EventSearch, PageSize: 50})
	if total != 1 {
		t.Errorf("search event filter: expected 1, got %d", total)
	}
}

func TestQueryByMailID(t *testing.T) {
	l := newTestAudit(t)

	l.Log(audit.Entry{EventType: audit.EventMailView, Username: "alice", MailID: "mail-001", Success: true})
	l.Log(audit.Entry{EventType: audit.EventMailView, Username: "bob", MailID: "mail-001", Success: true})
	l.Log(audit.Entry{EventType: audit.EventMailView, Username: "alice", MailID: "mail-002", Success: true})

	_, total, _ := l.Query(audit.QueryFilter{MailID: "mail-001", PageSize: 50})
	if total != 2 {
		t.Errorf("mailID filter: expected 2, got %d", total)
	}
}

func TestQueryDateRange(t *testing.T) {
	l := newTestAudit(t)

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", Success: true})
	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "bob", Success: true})

	// Query with future date range — should return 0
	future := time.Now().Add(24 * time.Hour)
	futureEnd := time.Now().Add(48 * time.Hour)
	_, total, _ := l.Query(audit.QueryFilter{From: &future, To: &futureEnd, PageSize: 50})
	if total != 0 {
		t.Errorf("future date range should return 0, got %d", total)
	}

	// Query with past-to-now range — should return all
	past := time.Now().Add(-1 * time.Minute)
	now := time.Now().Add(1 * time.Minute)
	_, total, _ = l.Query(audit.QueryFilter{From: &past, To: &now, PageSize: 50})
	if total != 2 {
		t.Errorf("current date range should return 2, got %d", total)
	}
}

func TestQueryPagination(t *testing.T) {
	l := newTestAudit(t)

	for i := 0; i < 10; i++ {
		l.Log(audit.Entry{EventType: audit.EventSearch, Username: "alice", Success: true})
	}

	page0, total, _ := l.Query(audit.QueryFilter{PageSize: 4, Page: 0})
	_, _, _ = l.Query(audit.QueryFilter{PageSize: 4, Page: 1})
	page2, _, _ := l.Query(audit.QueryFilter{PageSize: 4, Page: 2})

	if total != 10 {
		t.Errorf("total = %d, want 10", total)
	}
	if len(page0) != 4 {
		t.Errorf("page 0 len = %d, want 4", len(page0))
	}
	if len(page2) != 2 {
		t.Errorf("page 2 len = %d, want 2", len(page2))
	}
}

// TestImmutableTrigger verifies the PROJ-48 DB trigger rejects UPDATE and
// DELETE on audit_log through the normal application connection.
func TestImmutableTrigger(t *testing.T) {
	dsn, schemaDSN := testDSN(t)
	logger := slog.New(slog.NewTextHandler(os.Discard, nil))
	l, err := audit.New(schemaDSN, t.TempDir(), logger)
	if err != nil {
		t.Fatalf("audit.New: %v", err)
	}
	defer l.Close()

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", Success: true})

	// Connect through the same search_path to hit the protected table.
	_ = dsn
	ctx := context.Background()
	conn, err := pgx.Connect(ctx, schemaDSN)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	defer conn.Close(ctx)

	if _, err := conn.Exec(ctx, "UPDATE audit_log SET detail = 'tampered'"); err == nil {
		t.Error("UPDATE on audit_log should fail but succeeded")
	}
	if _, err := conn.Exec(ctx, "DELETE FROM audit_log"); err == nil {
		t.Error("DELETE on audit_log should fail but succeeded")
	}

	// INSERT must still work (verified indirectly via Query count).
	_, total, _ := l.Query(audit.QueryFilter{PageSize: 50})
	if total != 1 {
		t.Errorf("expected 1 surviving entry, got %d", total)
	}
}

// TestFileLogging verifies that each event is mirrored to the append-only
// JSON-Lines file (PROJ-48).
func TestFileLogging(t *testing.T) {
	_, schemaDSN := testDSN(t)
	logPath := filepath.Join(t.TempDir(), "audit.log")
	logger := slog.New(slog.NewTextHandler(os.Discard, nil))
	l, err := audit.New(schemaDSN, logPath, logger)
	if err != nil {
		t.Fatalf("audit.New: %v", err)
	}

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", IPAddress: "10.0.0.1", Success: true})
	l.Log(audit.Entry{EventType: audit.EventSearch, Username: "bob", Query: "invoice", Success: false, Detail: "denied"})
	l.Close()

	f, err := os.Open(logPath)
	if err != nil {
		t.Fatalf("open log file: %v", err)
	}
	defer f.Close()

	var lines []map[string]any
	sc := bufio.NewScanner(f)
	for sc.Scan() {
		var m map[string]any
		if err := json.Unmarshal(sc.Bytes(), &m); err != nil {
			t.Fatalf("invalid JSON line %q: %v", sc.Text(), err)
		}
		lines = append(lines, m)
	}
	if len(lines) != 2 {
		t.Fatalf("expected 2 log lines, got %d", len(lines))
	}
	if lines[0]["username"] != "alice" || lines[0]["event_type"] != "login" {
		t.Errorf("line 0 unexpected: %v", lines[0])
	}
	if _, err := time.Parse(time.RFC3339, lines[0]["timestamp"].(string)); err != nil {
		t.Errorf("timestamp not RFC3339: %v", lines[0]["timestamp"])
	}
}

// TestFileLoggingUnwritableContinues verifies the service tolerates an
// unwritable log path (DB-only logging continues, no panic).
func TestFileLoggingUnwritableContinues(t *testing.T) {
	_, schemaDSN := testDSN(t)
	// A directory cannot be opened for writing → file logging disabled.
	logPath := t.TempDir()
	logger := slog.New(slog.NewTextHandler(os.Discard, nil))
	l, err := audit.New(schemaDSN, logPath, logger)
	if err != nil {
		t.Fatalf("audit.New should not fail on unwritable path: %v", err)
	}
	defer l.Close()

	l.Log(audit.Entry{EventType: audit.EventLogin, Username: "alice", Success: true})
	_, total, _ := l.Query(audit.QueryFilter{PageSize: 50})
	if total != 1 {
		t.Errorf("DB logging must continue, got total=%d", total)
	}
}