package servertiming

import (
	"net/http"
	"reflect"
	"testing"
	"time"
)

// Example taken from the W3C spec
// see: https://w3c.github.io/server-timing/#examples
//
// ```
// > GET /resource HTTP/1.1
// > Host: example.com
//
//
// < HTTP/1.1 200 OK
// < Server-Timing: miss, db;dur=53, app;dur=47.2
// < Server-Timing: customView, dc;desc=atl
// < Server-Timing: cache;desc="Cache Read";dur=23.2
// < Trailer: Server-Timing
// < (... snip response body ...)
// < Server-Timing: total;dur=123.4
// ```
//
// | Name       | Duration | Description |
// | ---------- | -------- | ----------- |
// | miss       |          |             |
// | db         |       53 |             |
// | app        |     47.2 |             |
// | customView |          |             |
// | dc         |          | atl         |
// | cache      |     23.2 | Cache Read  |
// | total      |    123.4 |             |

func TestServerTiming_String(t *testing.T) {
	tests := []struct {
		name string
		st   ServerTiming
		want string
	}{
		{
			name: "just name",
			st:   ServerTiming{Name: "miss"},
			want: "miss",
		},
		{
			name: "name and dur",
			st: ServerTiming{
				Name: "db",
				Dur:  53 * time.Millisecond,
			},
			want: "db;dur=53",
		},
		{
			name: "name and decimal dur",
			st: ServerTiming{
				Name:             "app",
				Dur:              47_200 * time.Microsecond,
				DecimalPrecision: 1,
			},
			want: "app;dur=47.2",
		},
		{
			name: "name and nanosecond dur",
			st: ServerTiming{
				Name:             "app",
				Dur:              47_200 * time.Microsecond,
				DecimalPrecision: 6,
			},
			want: "app;dur=47.200000",
		},
		{
			name: "name and dur, negative precision",
			st: ServerTiming{
				Name:             "app",
				Dur:              47_200 * time.Microsecond,
				DecimalPrecision: -1,
			},
			want: "app;dur=47",
		},
		{
			name: "name and dur, out-of-bound precision",
			st: ServerTiming{
				Name:             "app",
				Dur:              47_200 * time.Microsecond,
				DecimalPrecision: 7,
			},
			want: "app;dur=47.200000",
		},
		{
			name: "name and desc",
			st: ServerTiming{
				Name: "dc",
				Desc: "atl",
			},
			want: "dc;desc=atl",
		},
		{
			name: "name, desc, and dur",
			st: ServerTiming{
				Name: "cache",
				Dur:  23 * time.Millisecond,
				Desc: "Cache Read",
			},
			want: "cache;dur=23;desc=Cache Read",
		},
		{
			name: "name, desc, and decimal dur",
			st: ServerTiming{
				Name:             "cache",
				Dur:              23_200 * time.Microsecond,
				Desc:             "Cache Read",
				DecimalPrecision: 1,
			},
			want: "cache;dur=23.2;desc=Cache Read",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := tt.st.String(); got != tt.want {
				t.Errorf("ServerTiming.String() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestFromString(t *testing.T) {
	tests := []struct {
		name string
		s    string
		want ServerTiming
	}{
		{
			name: "empty",
			s:    "",
			want: ServerTiming{},
		},
		{
			name: "name only",
			s:    "miss",
			want: ServerTiming{Name: "miss"},
		},
		{
			name: "name and dur",
			s:    "db;dur=53",
			want: ServerTiming{
				Name: "db",
				Dur:  53 * time.Millisecond,
			},
		},
		{
			name: "name, dur and desc",
			s:    "cache;dur=23;desc=Cache Read",
			want: ServerTiming{
				Name: "cache",
				Dur:  23 * time.Millisecond,
				Desc: "Cache Read",
			},
		},
		{
			name: "name, desc",
			s:    "cache;desc=Cache Read;dur=23",
			want: ServerTiming{
				Name: "cache",
				Dur:  23 * time.Millisecond,
				Desc: "Cache Read",
			},
		},
		{
			name: "name, dur and desc with padding",
			s:    "cache  ;   dur=23 ;    desc=Cache Read    ",
			want: ServerTiming{
				Name: "cache",
				Dur:  23 * time.Millisecond,
				Desc: "Cache Read",
			},
		},
		{
			name: "name and decimal dur",
			s:    "cache;dur=23.2",
			want: ServerTiming{
				Name: "cache",
				Dur:  23_200 * time.Microsecond,
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := FromString(tt.s); !reflect.DeepEqual(got, tt.want) {
				t.Errorf("FromString() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestAppend(t *testing.T) {
	resp := &http.Response{
		Header: http.Header{},
	}

	tests := []struct {
		name string
		st   ServerTiming
	}{
		{
			name: "name only",
			st:   ServerTiming{Name: "miss"},
		},
		{
			name: "name and dur",
			st: ServerTiming{
				Name: "db",
				Dur:  53 * time.Millisecond,
			},
		},
		{
			name: "name, dur and desc",
			st: ServerTiming{
				Name: "cache",
				Dur:  23 * time.Millisecond,
				Desc: "Cache Read",
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			Append(resp, tt.st)
		})
	}

	vals := resp.Header.Values("Server-Timing")
	if len(vals) != len(tests) {
		t.Errorf("Expected %d values in the headers, got %d", len(tests), len(vals))
	}

	for i, v := range vals {
		if v != tests[i].st.String() {
			t.Errorf("Expected '%s', got %s", tests[i].st.String(), v)
		}
	}
}

func TestTrailer(t *testing.T) {
	type args struct {
		r *http.Response
		t ServerTiming
	}
	tests := []struct {
		name string
		args args
	}{
		// TODO: Add test cases.
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			Trailer(tt.args.r, tt.args.t)
		})
	}
}

func TestParse(t *testing.T) {
	resp := &http.Response{
		Header:  http.Header{},
		Trailer: http.Header{},
	}
	resp.Header.Add("Server-Timing", "miss, db;dur=53, app;dur=47")
	resp.Header.Add("Server-Timing", "customView, dc;desc=atl")
	resp.Header.Add("Server-Timing", `cache;desc="Cache Read";dur=23`)
	resp.Trailer.Add("Server-Timing", "total;dur=123")

	timings := Parse(resp)
	if len(timings) != 7 {
		t.Errorf("Expected 7 timings, got %d", len(timings))
	}
}

func TestParseWithDecimal(t *testing.T) {
	resp := &http.Response{
		Header:  http.Header{},
		Trailer: http.Header{},
	}
	resp.Header.Add("Server-Timing", "miss, db;dur=53, app;dur=47.2")
	resp.Header.Add("Server-Timing", "customView, dc;desc=atl")
	resp.Header.Add("Server-Timing", `cache;desc="Cache Read";dur=23.2`)
	resp.Trailer.Add("Server-Timing", "total;dur=123.4")

	timings := Parse(resp)
	if len(timings) != 7 {
		t.Errorf("Expected 7 timings, got %d", len(timings))
	}
}