package wshub

import (
	"math"
	"testing"
)

// dump returns the ring's contents oldest-first, which is what every reader
// sees through slice() but is easier to assert on directly.
func dump(rb *sigRing) ([]float64, []float64) {
	return rb.slice(math.Inf(-1), math.Inf(1))
}

func TestRingBucketStoresMinMaxPairsInTimeOrder(t *testing.T) {
	rb := newSigRing(100)
	rb.setBucket(4)
	// Two buckets. In the first the minimum comes before the maximum, in the
	// second the order is reversed, so the emitted pairs must not be sorted by
	// value — a ring whose timestamps are not monotonic breaks slice()'s
	// binary search.
	ts := []float64{0, 1, 2, 3, 4, 5, 6, 7}
	vs := []float64{-5, 0, 0, 9, 9, 0, 0, -5}
	rb.write(ts, vs)

	gotT, gotV := dump(rb)
	wantT := []float64{0, 3, 4, 7}
	wantV := []float64{-5, 9, 9, -5}
	if len(gotT) != len(wantT) {
		t.Fatalf("stored %d points, want %d", len(gotT), len(wantT))
	}
	for i := range wantT {
		if gotT[i] != wantT[i] || gotV[i] != wantV[i] {
			t.Fatalf("point %d = (%v,%v), want (%v,%v)", i, gotT[i], gotV[i], wantT[i], wantV[i])
		}
	}
}

func TestRingBucketExtendsTheSpanAFixedCapacityCovers(t *testing.T) {
	const cap = 200
	// 2000 samples at 1 kHz is 2 s, ten times what the capacity holds verbatim.
	ts := make([]float64, 2000)
	vs := make([]float64, 2000)
	for i := range ts {
		ts[i] = float64(i) * 1e-3
		vs[i] = math.Sin(float64(i))
	}

	full := newSigRing(cap)
	full.write(ts, vs)
	if _, span := full.stats(); span > 0.25 {
		t.Fatalf("full-rate ring spans %.3f s, expected ~0.2 s", span)
	}

	// bucket 20 turns 20 samples into 2 points, so the same capacity reaches
	// 10x further: 200/2*20 = 2000 samples = 2 s.
	bucketed := newSigRing(cap)
	bucketed.setBucket(20)
	bucketed.write(ts, vs)
	count, span := bucketed.stats()
	if count != cap {
		t.Fatalf("bucketed ring holds %d points, want the full %d", count, cap)
	}
	if span < 1.9 {
		t.Fatalf("bucketed ring spans %.3f s, want the whole ~2 s", span)
	}
}

func TestRingSourceRateIsUnaffectedByBucketing(t *testing.T) {
	rb := newSigRing(1000)
	rb.setBucket(50)
	ts := make([]float64, 5000)
	vs := make([]float64, 5000)
	for i := range ts {
		ts[i] = float64(i) * 1e-4 // 10 kHz
	}
	rb.write(ts, vs)

	got := rb.sourceRate()
	if math.Abs(got-10000) > 10 {
		t.Fatalf("sourceRate = %.1f, want ~10000", got)
	}
}

func TestSetBucketFlushesThePartialBucket(t *testing.T) {
	rb := newSigRing(100)
	rb.setBucket(10)
	// Three samples: not enough to close a bucket of 10, so nothing is stored
	// yet and they would be silently dropped by a re-bucket that just reset the
	// accumulator.
	rb.write([]float64{0, 1, 2}, []float64{7, -7, 0})
	if n, _ := rb.stats(); n != 0 {
		t.Fatalf("partial bucket already emitted %d points", n)
	}
	rb.setBucket(2)
	gotT, gotV := dump(rb)
	if len(gotT) != 2 || gotT[0] != 0 || gotV[0] != 7 || gotT[1] != 1 || gotV[1] != -7 {
		t.Fatalf("flushed pair = %v/%v, want t=[0 1] v=[7 -7]", gotT, gotV)
	}
}

func TestActiveWindowSecFallsBackToTheDefault(t *testing.T) {
	h := NewHub()
	if got := h.activeWindowSec(); got != defaultLiveWindowSec {
		t.Fatalf("activeWindowSec with no clients = %v, want %v", got, defaultLiveWindowSec)
	}
}

// Clients disagree about how far back they are plotting, and a buffer sized for
// the narrowest one leaves the others with nothing to zoom into.
func TestActiveWindowSecTakesTheWidestClientWindow(t *testing.T) {
	h := NewHub()
	narrow, wide, silent := &wsClient{}, &wsClient{}, &wsClient{}
	narrow.setDisplayWindowSec(1)
	wide.setDisplayWindowSec(120)
	h.clients[narrow], h.clients[wide], h.clients[silent] = true, true, true

	if got := h.activeWindowSec(); got != 120 {
		t.Fatalf("activeWindowSec = %v, want the widest 120", got)
	}
}

// An armed trigger owns the window: its pre-window has to be in the buffer
// before the trigger fires or the capture has nothing to back-fill from.
func TestActiveWindowSecPrefersTheArmedTrigger(t *testing.T) {
	h := NewHub()
	c := &wsClient{}
	c.setDisplayWindowSec(1)
	h.clients[c] = true
	h.trigger.SetConfig(trigConfig{signalKey: "s1:sig", windowSec: 45, mode: "normal"})

	if got := h.activeWindowSec(); got != 45 {
		t.Fatalf("activeWindowSec = %v, want the trigger's 45", got)
	}
}

func TestSetBucketToOneRestoresVerbatimStorage(t *testing.T) {
	rb := newSigRing(100)
	rb.setBucket(4)
	rb.setBucket(1)
	ts := []float64{0, 1, 2, 3}
	vs := []float64{1, 2, 3, 4}
	rb.write(ts, vs)
	gotT, _ := dump(rb)
	if len(gotT) != 4 {
		t.Fatalf("stored %d points, want all 4", len(gotT))
	}
}