package web

import (
	"strings"
	"testing"
	"time"
)

func TestABarChartDrawsOneBarPerValue(t *testing.T) {
	out := string(BarChart(Series{Values: []float64{1, 5, 3}}, "requests"))
	if n := strings.Count(out, "<rect"); n != 3 {
		t.Errorf("%d bars for 3 values", n)
	}
	if !strings.Contains(out, "peak 5 requests") {
		t.Errorf("the peak is not labelled: %s", out)
	}
}

func TestAnHourWithTrafficNeverLooksLikeOneWithout(t *testing.T) {
	// One request in an hour against a peak of ten thousand rounds to a bar of
	// zero height, and a chart where a busy hour and an idle one look identical
	// is worse than no chart.
	out := string(BarChart(Series{Values: []float64{10000, 1}}, "requests"))
	for _, frag := range []string{`height="0.00"`, `height="0"`} {
		if strings.Contains(out, frag) {
			t.Errorf("a non-zero value was drawn with no height: %s", out)
		}
	}
}

func TestAnEmptySeriesStillRendersAFrame(t *testing.T) {
	// A missing chart reads as a broken page; a flat one reads as no traffic,
	// which is the truth.
	for _, s := range []Series{{}, {Values: []float64{0, 0, 0}}} {
		out := string(BarChart(s, "requests"))
		if !strings.Contains(out, "<svg") {
			t.Error("no frame was drawn")
		}
		if !strings.Contains(out, "nothing recorded") {
			t.Errorf("an empty chart does not say so: %s", out)
		}
		if strings.Contains(out, "<rect") {
			t.Error("bars were drawn for an empty series")
		}
	}
}

func TestLabelsAreEscaped(t *testing.T) {
	// Tooltips carry text that came from somewhere else, and the output of this
	// function is marked as trusted HTML.
	out := string(BarChart(Series{
		Values: []float64{1},
		Labels: []string{`</title><script>alert(1)</script>`},
	}, "requests"))

	if strings.Contains(out, "<script>") {
		t.Fatalf("a label reached the markup unescaped: %s", out)
	}
	if !strings.Contains(out, "&lt;script&gt;") {
		t.Errorf("the label was dropped rather than escaped: %s", out)
	}
}

func TestTheUnitIsEscapedToo(t *testing.T) {
	out := string(BarChart(Series{Values: []float64{1}}, `"><script>alert(1)</script>`))
	if strings.Contains(out, "<script>") {
		t.Fatalf("the unit reached the markup unescaped: %s", out)
	}
}

func TestOnlyKnownColoursReachTheStyleAttribute(t *testing.T) {
	// A colour that could be anything is a way to write CSS into every page the
	// chart appears on.
	out := string(BarChart(Series{Values: []float64{1}, Colour: "red;}</style><script>x"}, "u"))
	if strings.Contains(out, "</style>") || strings.Contains(out, "script") {
		t.Fatalf("a colour escaped its attribute: %s", out)
	}
	if !strings.Contains(out, "var(--accent)") {
		t.Errorf("an unknown colour did not fall back: %s", out)
	}

	for _, ok := range []string{"--accent", "--ok", "--warn", "--bad"} {
		if got := cssVar(ok); got != ok {
			t.Errorf("cssVar(%q) = %q", ok, got)
		}
	}
}

func TestCompactNumbers(t *testing.T) {
	cases := map[float64]string{
		0: "0", 7: "7", 1500: "1.5k", 2_400_000: "2.4M", 3_100_000_000: "3.1B", 1.25: "1.2",
	}
	for in, want := range cases {
		if got := compact(in); got != want {
			t.Errorf("compact(%v) = %q, want %q", in, got, want)
		}
	}
}

func TestHourLabelsSayWhenAndHowMuch(t *testing.T) {
	at := time.Date(2026, 9, 16, 14, 0, 0, 0, time.UTC)
	got := hourLabel(at, 1500, "requests")
	if !strings.Contains(got, "1.5k requests") {
		t.Errorf("label = %q", got)
	}
}

func TestASmallFigureIsNotRenderedAsZero(t *testing.T) {
	// A spend of 0.03 units shown as "0.0" says nothing was spent. On a cluster
	// whose prices make a month's traffic a fraction of a unit, that is every
	// figure on the page.
	for _, c := range []struct {
		in   float64
		want string
	}{
		{0.03, "0.03"},
		{0.5, "0.5"},
		{0, "0"},
		{1, "1"},
		{1500, "1.5k"},
	} {
		if got := compact(c.in); got != c.want {
			t.Errorf("compact(%v) = %q, want %q", c.in, got, c.want)
		}
	}
}