// Copyright ©2017 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package testblas

import (
	"fmt"
	"testing"
)

type Zdotcer interface {
	Zdotc(n int, x []complex128, incX int, y []complex128, incY int) complex128
}

func ZdotcTest(t *testing.T, impl Zdotcer) {
	for tc, test := range []struct {
		x, y []complex128

		want    complex128 // Result when both increments have the same sign.
		wantRev complex128 // Result when the increments have opposite sign.
	}{
		{
			x:       nil,
			y:       nil,
			want:    0,
			wantRev: 0,
		},
		{
			x:       []complex128{1 + 2i},
			y:       []complex128{30 + 31i},
			want:    92 - 29i,
			wantRev: 92 - 29i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i},
			y:       []complex128{30 + 31i, 33 + 34i},
			want:    327 - 59i,
			wantRev: 315 - 59i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i},
			want:    729 - 90i,
			wantRev: 681 - 90i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i},
			want:    1322 - 122i,
			wantRev: 1202 - 122i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i},
			want:    2130 - 155i,
			wantRev: 1890 - 155i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i},
			want:    3177 - 189i,
			wantRev: 2757 - 189i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i},
			want:    4487 - 224i,
			wantRev: 3815 - 224i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i, 15 + 16i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i, 51 + 52i},
			want:    6084 - 260i,
			wantRev: 5076 - 260i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i, 15 + 16i, 17 + 18i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i, 51 + 52i, 54 + 55i},
			want:    7992 - 297i,
			wantRev: 6552 - 297i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i, 15 + 16i, 17 + 18i, 19 + 20i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i, 51 + 52i, 54 + 55i, 57 + 58i},
			want:    10235 - 335i,
			wantRev: 8255 - 335i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i, 15 + 16i, 17 + 18i, 19 + 20i, 21 + 22i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i, 51 + 52i, 54 + 55i, 57 + 58i, 60 + 61i},
			want:    12837 - 374i,
			wantRev: 10197 - 374i,
		},
		{
			x:       []complex128{1 + 2i, 3 + 4i, 5 + 6i, 7 + 8i, 9 + 10i, 11 + 12i, 13 + 14i, 15 + 16i, 17 + 18i, 19 + 20i, 21 + 22i, 23 + 24i},
			y:       []complex128{30 + 31i, 33 + 34i, 36 + 37i, 39 + 40i, 42 + 43i, 45 + 46i, 48 + 49i, 51 + 52i, 54 + 55i, 57 + 58i, 60 + 61i, 63 + 64i},
			want:    15822 - 414i,
			wantRev: 12390 - 414i,
		},
	} {
		n := len(test.x)
		if len(test.y) != n {
			panic("bad test")
		}
		for _, inc := range allPairs([]int{-7, -3, 1, 13}, []int{-11, -5, 1, 17}) {
			incX := inc[0]
			incY := inc[1]

			x := makeZVector(test.x, incX)
			xCopy := make([]complex128, len(x))
			copy(xCopy, x)

			y := makeZVector(test.y, incY)
			yCopy := make([]complex128, len(y))
			copy(yCopy, y)

			want := test.want
			if incX*incY < 0 {
				want = test.wantRev
			}

			got := impl.Zdotc(n, x, incX, y, incY)

			prefix := fmt.Sprintf("Case %v (incX=%v,incY=%v):", tc, incX, incY)

			if !zsame(x, xCopy) {
				t.Errorf("%v: unexpected modification of x", prefix)
			}
			if !zsame(y, yCopy) {
				t.Errorf("%v: unexpected modification of y", prefix)
			}

			if got != want {
				t.Errorf("%v: unexpected result. want %v, got %v", prefix, want, got)
			}
		}
	}
}