package web

import (
	"bytes"
	"encoding/binary"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"pcap-web-tools/internal/pcap"
)

func TestBuildPacketConcatenatesWithoutFix(t *testing.T) {
	res, err := buildPacket(hex2pcapForm{L2: "aa bb", L3: "cc", L7: "dd:ee"})
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(res.Packet, []byte{0xaa, 0xbb, 0xcc, 0xdd, 0xee}) {
		t.Errorf("packet %x", res.Packet)
	}
	if res.LinkType != pcap.LinkTypeEthernet || res.Fixed {
		t.Errorf("link type %d fixed %v", res.LinkType, res.Fixed)
	}
}

func TestBuildPacketLinkType(t *testing.T) {
	tests := []struct {
		form hex2pcapForm
		want uint32
	}{
		{hex2pcapForm{L3: "45"}, pcap.LinkTypeRaw},
		{hex2pcapForm{L2: "00", L3: "45"}, pcap.LinkTypeEthernet},
		{hex2pcapForm{L7: "00"}, pcap.LinkTypeEthernet},
		{hex2pcapForm{L3: "45", LinkType: "113"}, pcap.LinkTypeLinuxSLL},
		{hex2pcapForm{L7: "00", LinkType: "custom", CustomLinkType: "228"}, 228},
		{hex2pcapForm{L7: "00", LinkType: "custom", CustomLinkType: "0x93"}, 147},
	}
	for _, tt := range tests {
		res, err := buildPacket(tt.form)
		if err != nil {
			t.Errorf("%+v: %v", tt.form, err)
			continue
		}
		if res.LinkType != tt.want {
			t.Errorf("%+v: link type %d, want %d", tt.form, res.LinkType, tt.want)
		}
	}
}

func TestBuildPacketFixWholeFrameInPayload(t *testing.T) {
	// Full Ethernet + IPv4 + ICMP frame pasted into the payload field only.
	res, err := buildPacket(hex2pcapForm{
		L7:  "00112233445566778899aabb0800 45000000000100004001 0000 c0a8000108080808 0800 0000 abcd0001",
		Fix: true,
	})
	if err != nil {
		t.Fatal(err)
	}
	if res.IPOffset != 14 {
		t.Errorf("IP offset %d, want 14", res.IPOffset)
	}
	if got := binary.BigEndian.Uint16(res.Packet[14+2:]); got != 28 {
		t.Errorf("IPv4 total length %d, want 28", got)
	}
}

func TestBuildPacketFixUsesLayer3Boundary(t *testing.T) {
	// IPv4 with a 4 byte option and TCP with 12 bytes of options in layer 3:
	// the TCP data offset is set from where the layer 3 field ends.
	res, err := buildPacket(hex2pcapForm{
		L3:  "46000000123440004006 0000 0a0000010a000002 94040000  c350005000000001000000000018ffff00000000 0101080a0000000100000000",
		L7:  "474554202f",
		Fix: true,
	})
	if err != nil {
		t.Fatal(err)
	}
	if got := res.Packet[24+12] >> 4; got != 8 {
		t.Errorf("TCP data offset %d, want 8", got)
	}
}

func TestBuildPacketErrors(t *testing.T) {
	for name, f := range map[string]hex2pcapForm{
		"empty":          {},
		"bad hex":        {L3: "4g"},
		"fix non-IP":     {L7: "ffffffffffff 66778899aabb 0806 0001", Fix: true},
		"bad custom":     {L7: "00", LinkType: "custom", CustomLinkType: "x"},
		"fix not IP hdr": {L3: "00", Fix: true},
	} {
		if _, err := buildPacket(f); err == nil {
			t.Errorf("%s: expected error", name)
		}
	}
}

func TestPcapFilename(t *testing.T) {
	for in, want := range map[string]string{
		"":              "packet.pcap",
		"  ":            "packet.pcap",
		"dns query":     "dns_query.pcap",
		"x.pcap":        "x.pcap",
		"../etc/passwd": "passwd.pcap",
		`C:\\x\\y.pcap`: "y.pcap",
		`a"b`:           "a_b.pcap",
	} {
		if got := pcapFilename(in); got != want {
			t.Errorf("pcapFilename(%q) = %q, want %q", in, got, want)
		}
	}
}

func TestHandlers(t *testing.T) {
	srv, err := New(Config{MaxUploadBytes: 1 << 20})
	if err != nil {
		t.Fatal(err)
	}

	for _, path := range []string{"/", "/hex2pcap", "/hex2pcap?example", "/static/style.css"} {
		rec := httptest.NewRecorder()
		srv.ServeHTTP(rec, httptest.NewRequest("GET", path, nil))
		if rec.Code != http.StatusOK {
			t.Errorf("GET %s: %d", path, rec.Code)
		}
	}

	post := func(v url.Values) *httptest.ResponseRecorder {
		req := httptest.NewRequest("POST", "/hex2pcap", strings.NewReader(v.Encode()))
		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		rec := httptest.NewRecorder()
		srv.ServeHTTP(rec, req)
		return rec
	}

	rec := post(url.Values{"l3": {"4500"}, "l7": {"aabb"}, "action": {"download"}, "filename": {"test"}})
	if rec.Code != http.StatusOK {
		t.Fatalf("download: %d %s", rec.Code, rec.Body)
	}
	if cd := rec.Header().Get("Content-Disposition"); cd != `attachment; filename="test.pcap"` {
		t.Errorf("Content-Disposition %q", cd)
	}
	body := rec.Body.Bytes()
	if len(body) != 24+16+4 || binary.LittleEndian.Uint32(body[20:]) != pcap.LinkTypeRaw {
		t.Errorf("pcap body %x", body)
	}

	rec = post(url.Values{"l3": {"4500"}, "action": {"preview"}})
	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), "Hex dump") {
		t.Errorf("preview: %d", rec.Code)
	}

	rec = post(url.Values{"l3": {"zz"}, "action": {"download"}})
	if rec.Code != http.StatusBadRequest || !strings.Contains(rec.Body.String(), "invalid character") {
		t.Errorf("bad hex: %d", rec.Code)
	}
}