package qlog

import (
	"bytes"
	"encoding/json"
	"testing"

	"github.com/quic-go/quic-go/qlogwriter/jsontext"

	"github.com/stretchr/testify/require"
)

func check(t *testing.T, f any, expected map[string]any) {
	t.Helper()

	var buf bytes.Buffer
	enc := jsontext.NewEncoder(&buf)
	require.NoError(t, (Frame{Frame: f}).encode(enc))
	data := buf.Bytes()
	require.True(t, json.Valid(data), "invalid JSON: %s", string(data))
	checkEncoding(t, data, expected)
}

func checkEncoding(t *testing.T, data []byte, expected map[string]any) {
	t.Helper()

	m := make(map[string]any)
	require.NoError(t, json.Unmarshal(data, &m))
	require.Len(t, m, len(expected))

	for key, value := range expected {
		switch v := value.(type) {
		case bool, string, map[string]any:
			require.Equal(t, v, m[key])
		case int:
			require.Equal(t, float64(v), m[key])
		case float64:
			require.Equal(t, v, m[key])
		case []map[string]any: // used for header fields
			require.Contains(t, m, key)
			slice, ok := m[key].([]any)
			require.True(t, ok)
			require.Len(t, slice, len(v))
			for i, expectedField := range v {
				field, ok := slice[i].(map[string]any)
				require.True(t, ok)
				require.Equal(t, expectedField, field)
			}
		default:
			t.Fatalf("unexpected type: %T", v)
		}
	}
}

func TestDataFrame(t *testing.T) {
	check(t, DataFrame{}, map[string]any{
		"frame_type": "data",
	})
}

func TestHeadersFrame(t *testing.T) {
	check(t, HeadersFrame{
		HeaderFields: []HeaderField{
			{Name: ":status", Value: "200"},
			{Name: "content-type", Value: "application/json"},
		},
	}, map[string]any{
		"frame_type": "headers",
		"header_fields": []map[string]any{
			{"name": ":status", "value": "200"},
			{"name": "content-type", "value": "application/json"},
		},
	})
}

func TestGoAwayFrame(t *testing.T) {
	check(t, GoAwayFrame{StreamID: 1337}, map[string]any{
		"frame_type": "goaway",
		"id":         1337,
	})
}

func pointer[T any](v T) *T {
	return &v
}

func TestSettingsFrame(t *testing.T) {
	tests := []struct {
		name     string
		frame    SettingsFrame
		expected map[string]any
	}{
		{
			name: "datagram: true",
			frame: SettingsFrame{
				MaxFieldSectionSize: -1,
				Datagram:            pointer(true),
			},
			expected: map[string]any{
				"frame_type": "settings",
				"settings": []map[string]any{{
					"name":  "settings_h3_datagram",
					"value": true,
				}},
			},
		},
		{
			name: "extended_connect: false",
			frame: SettingsFrame{
				MaxFieldSectionSize: -1,
				ExtendedConnect:     pointer(false),
			},
			expected: map[string]any{
				"frame_type": "settings",
				"settings": []map[string]any{{
					"name":  "settings_enable_connect_protocol",
					"value": false,
				}},
			},
		},
		{
			name:  "max_field_section_size",
			frame: SettingsFrame{MaxFieldSectionSize: 1337},
			expected: map[string]any{
				"frame_type": "settings",
				"settings": []map[string]any{{
					"name":  "settings_max_field_section_size",
					"value": float64(1337),
				}},
			},
		},
		{
			name: "datagram: false, extended_connect: false",
			frame: SettingsFrame{
				MaxFieldSectionSize: -1,
				Datagram:            pointer(false),
				ExtendedConnect:     pointer(false),
			},
			expected: map[string]any{
				"frame_type": "settings",
				"settings": []map[string]any{
					{"name": "settings_h3_datagram", "value": false},
					{"name": "settings_enable_connect_protocol", "value": false},
				},
			},
		},
		{
			name: "unknowns",
			// Only test a single unknown setting.
			// Testing multiple unknown settings doesn't add a lot of value,
			// and would require us to deal with non-deterministic map iteration order.
			frame: SettingsFrame{
				MaxFieldSectionSize: -1,
				Other:               map[uint64]uint64{0xdead: 0xbeef},
			},
			expected: map[string]any{
				"frame_type": "settings",
				"settings": []map[string]any{{
					"name":       "unknown",
					"name_bytes": float64(0xdead),
					"value":      float64(0xbeef),
				}},
			},
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			check(t, tc.frame, tc.expected)
		})
	}
}

func TestPushPromiseFrame(t *testing.T) {
	check(t, PushPromiseFrame{}, map[string]any{
		"frame_type": "push_promise",
	})
}

func TestCancelPushFrame(t *testing.T) {
	check(t, CancelPushFrame{}, map[string]any{
		"frame_type": "cancel_push",
	})
}

func TestMaxPushIDFrame(t *testing.T) {
	check(t, MaxPushIDFrame{}, map[string]any{
		"frame_type": "max_push_id",
	})
}

func TestReservedFrame(t *testing.T) {
	check(t, ReservedFrame{Type: 0x1f}, map[string]any{
		"frame_type":       "reserved",
		"frame_type_bytes": 0x1f,
	})
}

func TestUnknownFrame(t *testing.T) {
	check(t, UnknownFrame{Type: 0x2a}, map[string]any{
		"frame_type":       "unknown",
		"frame_type_bytes": 0x2a,
	})
}