package cln16sidh

import (
	"math/rand"
	"reflect"
	"testing"
	"testing/quick"
)

// Sage script for generating test vectors:
// sage: p = 2^372 * 3^239 - 1; Fp = GF(p)
// sage: R.<x> = Fp[]
// sage: Fp2 = Fp.extension(x^2 + 1, 'i')
// sage: i = Fp2.gen()
// sage: A = 4385300808024233870220415655826946795549183378139271271040522089756750951667981765872679172832050962894122367066234419550072004266298327417513857609747116903999863022476533671840646615759860564818837299058134292387429068536219*i + 1408083354499944307008104531475821995920666351413327060806684084512082259107262519686546161682384352696826343970108773343853651664489352092568012759783386151707999371397181344707721407830640876552312524779901115054295865393760
// sage: C = 933177602672972392833143808100058748100491911694554386487433154761658932801917030685312352302083870852688835968069519091048283111836766101703759957146191882367397129269726925521881467635358356591977198680477382414690421049768*i + 9088894745865170214288643088620446862479558967886622582768682946704447519087179261631044546285104919696820250567182021319063155067584445633834024992188567423889559216759336548208016316396859149888322907914724065641454773776307
// sage: E = EllipticCurve(Fp2, [0,A/C,0,1,0])
// sage: X, Y, Z = (8172151271761071554796221948801462094972242987811852753144865524899433583596839357223411088919388342364651632180452081960511516040935428737829624206426287774255114241789158000915683252363913079335550843837650671094705509470594*i + 9326574858039944121604015439381720195556183422719505497448541073272720545047742235526963773359004021838961919129020087515274115525812121436661025030481584576474033630899768377131534320053412545346268645085054880212827284581557, 2381174772709336084066332457520782192315178511983342038392622832616744048226360647551642232950959910067260611740876401494529727990031260499974773548012283808741733925525689114517493995359390158666069816204787133942283380884077*i + 5378956232034228335189697969144556552783858755832284194802470922976054645696324118966333158267442767138528227968841257817537239745277092206433048875637709652271370008564179304718555812947398374153513738054572355903547642836171, 1)
// sage: P = E((X,Y,Z))
// sage: X2, Y2, Z2 = 2*P
// sage: X3, Y3, Z3 = 3*P
// sage: m = 96550223052359874398280314003345143371473380422728857598463622014420884224892

// A = 4385300808024233870220415655826946795549183378139271271040522089756750951667981765872679172832050962894122367066234419550072004266298327417513857609747116903999863022476533671840646615759860564818837299058134292387429068536219*i + 1408083354499944307008104531475821995920666351413327060806684084512082259107262519686546161682384352696826343970108773343853651664489352092568012759783386151707999371397181344707721407830640876552312524779901115054295865393760
var curve_A = ExtensionFieldElement{a: fp751Element{0x8319eb18ca2c435e, 0x3a93beae72cd0267, 0x5e465e1f72fd5a84, 0x8617fa4150aa7272, 0x887da24799d62a13, 0xb079b31b3c7667fe, 0xc4661b150fa14f2e, 0xd4d2b2967bc6efd6, 0x854215a8b7239003, 0x61c5302ccba656c2, 0xf93194a27d6f97a2, 0x1ed9532bca75}, b: fp751Element{0xb6f541040e8c7db6, 0x99403e7365342e15, 0x457e9cee7c29cced, 0x8ece72dc073b1d67, 0x6e73cef17ad28d28, 0x7aed836ca317472, 0x89e1de9454263b54, 0x745329277aa0071b, 0xf623dfc73bc86b9b, 0xb8e3c1d8a9245882, 0x6ad0b3d317770bec, 0x5b406e8d502b}}

// C = 933177602672972392833143808100058748100491911694554386487433154761658932801917030685312352302083870852688835968069519091048283111836766101703759957146191882367397129269726925521881467635358356591977198680477382414690421049768*i + 9088894745865170214288643088620446862479558967886622582768682946704447519087179261631044546285104919696820250567182021319063155067584445633834024992188567423889559216759336548208016316396859149888322907914724065641454773776307
var curve_C = ExtensionFieldElement{a: fp751Element{0x4fb2358bbf723107, 0x3a791521ac79e240, 0x283e24ef7c4c922f, 0xc89baa1205e33cc, 0x3031be81cff6fee1, 0xaf7a494a2f6a95c4, 0x248d251eaac83a1d, 0xc122fca1e2550c88, 0xbc0451b11b6cfd3d, 0x9c0a114ab046222c, 0x43b957b32f21f6ea, 0x5b9c87fa61de}, b: fp751Element{0xacf142afaac15ec6, 0xfd1322a504a071d5, 0x56bb205e10f6c5c6, 0xe204d2849a97b9bd, 0x40b0122202fe7f2e, 0xecf72c6fafacf2cb, 0x45dfc681f869f60a, 0x11814c9aff4af66c, 0x9278b0c4eea54fe7, 0x9a633d5baf7f2e2e, 0x69a329e6f1a05112, 0x1d874ace23e4}}

var curve = ProjectiveCurveParameters{A: curve_A, C: curve_C}

// x(P) = 8172151271761071554796221948801462094972242987811852753144865524899433583596839357223411088919388342364651632180452081960511516040935428737829624206426287774255114241789158000915683252363913079335550843837650671094705509470594*i + 9326574858039944121604015439381720195556183422719505497448541073272720545047742235526963773359004021838961919129020087515274115525812121436661025030481584576474033630899768377131534320053412545346268645085054880212827284581557
var affine_xP = ExtensionFieldElement{a: fp751Element{0xe8d05f30aac47247, 0x576ec00c55441de7, 0xbf1a8ec5fe558518, 0xd77cb17f77515881, 0x8e9852837ee73ec4, 0x8159634ad4f44a6b, 0x2e4eb5533a798c5, 0x9be8c4354d5bc849, 0xf47dc61806496b84, 0x25d0e130295120e0, 0xdbef54095f8139e3, 0x5a724f20862c}, b: fp751Element{0x3ca30d7623602e30, 0xfb281eddf45f07b7, 0xd2bf62d5901a45bc, 0xc67c9baf86306dd2, 0x4e2bd93093f538ca, 0xcfd92075c25b9cbe, 0xceafe9a3095bcbab, 0x7d928ad380c85414, 0x37c5f38b2afdc095, 0x75325899a7b779f4, 0xf130568249f20fdd, 0x178f264767d1}}

// x([2]P) = 1476586462090705633631615225226507185986710728845281579274759750260315746890216330325246185232948298241128541272709769576682305216876843626191069809810990267291824247158062860010264352034514805065784938198193493333201179504845*i + 3623708673253635214546781153561465284135688791018117615357700171724097420944592557655719832228709144190233454198555848137097153934561706150196041331832421059972652530564323645509890008896574678228045006354394485640545367112224
var affine_xP2 = ExtensionFieldElement{a: fp751Element{0x2a77afa8576ce979, 0xab1360e69b0aeba0, 0xd79e3e3cbffad660, 0x5fd0175aa10f106b, 0x1800ebafce9fbdbc, 0x228fc9142bdd6166, 0x867cf907314e34c3, 0xa58d18c94c13c31c, 0x699a5bc78b11499f, 0xa29fc29a01f7ccf1, 0x6c69c0c5347eebce, 0x38ecee0cc57}, b: fp751Element{0x43607fd5f4837da0, 0x560bad4ce27f8f4a, 0x2164927f8495b4dd, 0x621103fdb831a997, 0xad740c4eea7db2db, 0x2cde0442205096cd, 0x2af51a70ede8324e, 0x41a4e680b9f3466, 0x5481f74660b8f476, 0xfcb2f3e656ff4d18, 0x42e3ce0837171acc, 0x44238c30530c}}

// x([3]P) = 9351941061182433396254169746041546943662317734130813745868897924918150043217746763025923323891372857734564353401396667570940585840576256269386471444236630417779544535291208627646172485976486155620044292287052393847140181703665*i + 9010417309438761934687053906541862978676948345305618417255296028956221117900864204687119686555681136336037659036201780543527957809743092793196559099050594959988453765829339642265399496041485088089691808244290286521100323250273
var affine_xP3 = ExtensionFieldElement{a: fp751Element{0x2096e3f23feca947, 0xf36f635aa4ad8634, 0xdae3b1c6983c5e9a, 0xe08df6c262cb74b4, 0xd2ca4edc37452d3d, 0xfb5f3fe42f500c79, 0x73740aa3abc2b21f, 0xd535fd869f914cca, 0x4a558466823fb67f, 0x3e50a7a0e3bfc715, 0xf43c6da9183a132f, 0x61aca1e1b8b9}, b: fp751Element{0x1e54ec26ea5077bd, 0x61380572d8769f9a, 0xc615170684f59818, 0x6309c3b93e84ef6e, 0x33c74b1318c3fcd0, 0xfe8d7956835afb14, 0x2d5a7b55423c1ecc, 0x869db67edfafea68, 0x1292632394f0a628, 0x10bba48225bfd141, 0x6466c28b408daba, 0x63cacfdb7c43}}

// m = 96550223052359874398280314003345143371473380422728857598463622014420884224892
var mScalarBytes = [...]uint8{124, 123, 149, 250, 180, 117, 108, 72, 140, 23, 85, 180, 73, 245, 30, 163, 11, 49, 240, 164, 166, 129, 173, 148, 81, 17, 231, 245, 91, 125, 117, 213}

// x([a]P) = 7893578558852400052689739833699289348717964559651707250677393044951777272628231794999463214496545377542328262828965953246725804301238040891993859185944339366910592967840967752138115122568615081881937109746463885908097382992642*i + 8293895847098220389503562888233557012043261770526854885191188476280014204211818299871679993460086974249554528517413590157845430186202704783785316202196966198176323445986064452630594623103149383929503089342736311904030571524837
var affine_xaP = ExtensionFieldElement{a: fp751Element{0x2112f3c7d7f938bb, 0x704a677f0a4df08f, 0x825370e31fb4ef00, 0xddbf79b7469f902, 0x27640c899ea739fd, 0xfb7b8b19f244108e, 0x546a6679dd3baebc, 0xe9f0ecf398d5265f, 0x223d2b350e75e461, 0x84b322a0b6aff016, 0xfabe426f539f8b39, 0x4507a0604f50}, b: fp751Element{0xac77737e5618a5fe, 0xf91c0e08c436ca52, 0xd124037bc323533c, 0xc9a772bf52c58b63, 0x3b30c8f38ef6af4d, 0xb9eed160e134f36e, 0x24e3836393b25017, 0xc828be1b11baf1d9, 0x7b7dab585df50e93, 0x1ca3852c618bd8e0, 0x4efa73bcb359fa00, 0x50b6a923c2d4}}

var one = ExtensionFieldElement{a: fp751Element{0x249ad, 0x0, 0x0, 0x0, 0x0, 0x8310000000000000, 0x5527b1e4375c6c66, 0x697797bf3f4f24d0, 0xc89db7b2ac5c4e2e, 0x4ca4b439d2076956, 0x10f7926c7512c7e9, 0x2d5b24bce5e2}, b: fp751Element{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}

func TestOne(t *testing.T) {
	var tmp ExtensionFieldElement
	tmp.Mul(&one, &affine_xP)
	if !tmp.VartimeEq(&affine_xP) {
		t.Error("Not equal 1")
	}
}

func (P ProjectivePoint) Generate(rand *rand.Rand, size int) reflect.Value {
	f := ExtensionFieldElement{}
	x, _ := f.Generate(rand, size).Interface().(ExtensionFieldElement)
	z, _ := f.Generate(rand, size).Interface().(ExtensionFieldElement)
	return reflect.ValueOf(ProjectivePoint{
		x: x,
		z: z,
	})
}

func (curve ProjectiveCurveParameters) Generate(rand *rand.Rand, size int) reflect.Value {
	f := ExtensionFieldElement{}
	A, _ := f.Generate(rand, size).Interface().(ExtensionFieldElement)
	C, _ := f.Generate(rand, size).Interface().(ExtensionFieldElement)
	return reflect.ValueOf(ProjectiveCurveParameters{
		A: A,
		C: C,
	})
}

func Test_jInvariant(t *testing.T) {
	var curve = ProjectiveCurveParameters{A: curve_A, C: curve_C}
	j := curve.jInvariant()
	// Computed using Sage
	// j = 3674553797500778604587777859668542828244523188705960771798425843588160903687122861541242595678107095655647237100722594066610650373491179241544334443939077738732728884873568393760629500307797547379838602108296735640313894560419*i + 3127495302417548295242630557836520229396092255080675419212556702820583041296798857582303163183558315662015469648040494128968509467224910895884358424271180055990446576645240058960358037224785786494172548090318531038910933793845
	known_j := ExtensionFieldElement{
		a: fp751Element{0xc7a8921c1fb23993, 0xa20aea321327620b, 0xf1caa17ed9676fa8, 0x61b780e6b1a04037, 0x47784af4c24acc7a, 0x83926e2e300b9adf, 0xcd891d56fae5b66, 0x49b66985beb733bc, 0xd4bcd2a473d518f, 0xe242239991abe224, 0xa8af5b20f98672f8, 0x139e4d4e4d98},
		b: fp751Element{0xb5b52a21f81f359, 0x715e3a865db6d920, 0x9bac2f9d8911978b, 0xef14acd8ac4c1e3d, 0xe81aacd90cfb09c8, 0xaf898288de4a09d9, 0xb85a7fb88c5c4601, 0x2c37c3f1dd303387, 0x7ad3277fe332367c, 0xd4cbee7f25a8e6f8, 0x36eacbe979eaeffa, 0x59eb5a13ac33},
	}

	if !j.VartimeEq(&known_j) {
		t.Error("Computed incorrect j-invariant: found\n", j, "\nexpected\n", known_j)
	}
}

func TestProjectivePointVartimeEq(t *testing.T) {
	xP := ProjectivePoint{x: affine_xP, z: one}
	xQ := xP
	// Scale xQ, which results in the same projective point
	xQ.x.Mul(&xQ.x, &curve_A)
	xQ.z.Mul(&xQ.z, &curve_A)
	if !xQ.VartimeEq(&xP) {
		t.Error("Expected the scaled point to be equal to the original")
	}
}

func TestPointDoubleVersusSage(t *testing.T) {
	var curve = ProjectiveCurveParameters{A: curve_A, C: curve_C}
	var xP, xQ ProjectivePoint
	xP = ProjectivePoint{x: affine_xP, z: one}
	affine_xQ := xQ.Pow2k(&curve, &xP, 1).toAffine()

	if !affine_xQ.VartimeEq(&affine_xP2) {
		t.Error("\nExpected\n", affine_xP2, "\nfound\n", affine_xQ)
	}
}

func TestPointTripleVersusSage(t *testing.T) {
	var curve = ProjectiveCurveParameters{A: curve_A, C: curve_C}
	var xP, xQ ProjectivePoint
	xP = ProjectivePoint{x: affine_xP, z: one}
	affine_xQ := xQ.Pow3k(&curve, &xP, 1).toAffine()

	if !affine_xQ.VartimeEq(&affine_xP3) {
		t.Error("\nExpected\n", affine_xP3, "\nfound\n", affine_xQ)
	}
}

func TestPointPow2kVersusScalarMult(t *testing.T) {
	var xP, xQ, xR ProjectivePoint
	xP = ProjectivePoint{x: affine_xP, z: one}
	affine_xQ := xQ.Pow2k(&curve, &xP, 5).toAffine()               // = x([32]P)
	affine_xR := xR.ScalarMult(&curve, &xP, []byte{32}).toAffine() // = x([32]P)

	if !affine_xQ.VartimeEq(affine_xR) {
		t.Error("\nExpected\n", affine_xQ, "\nfound\n", affine_xR)
	}
}

func TestScalarMultVersusSage(t *testing.T) {
	xP := ProjectivePoint{x: affine_xP, z: one}
	affine_xQ := xP.ScalarMult(&curve, &xP, mScalarBytes[:]).toAffine() // = x([m]P)

	if !affine_xaP.VartimeEq(affine_xQ) {
		t.Error("\nExpected\n", affine_xaP, "\nfound\n", affine_xQ)
	}
}

func TestThreePointLadderVersusSage(t *testing.T) {
	var xP, xQ, xPmQ, xR ProjectivePoint

	xP.x = ExtensionFieldElement{a: fp751Element{0xe8d05f30aac47247, 0x576ec00c55441de7, 0xbf1a8ec5fe558518, 0xd77cb17f77515881, 0x8e9852837ee73ec4, 0x8159634ad4f44a6b, 0x2e4eb5533a798c5, 0x9be8c4354d5bc849, 0xf47dc61806496b84, 0x25d0e130295120e0, 0xdbef54095f8139e3, 0x5a724f20862c}, b: fp751Element{0x3ca30d7623602e30, 0xfb281eddf45f07b7, 0xd2bf62d5901a45bc, 0xc67c9baf86306dd2, 0x4e2bd93093f538ca, 0xcfd92075c25b9cbe, 0xceafe9a3095bcbab, 0x7d928ad380c85414, 0x37c5f38b2afdc095, 0x75325899a7b779f4, 0xf130568249f20fdd, 0x178f264767d1}}
	xP.z.One()

	xQ.x = ExtensionFieldElement{a: fp751Element{0x2b71a2a93ad1e10e, 0xf0b9842a92cfb333, 0xae17373615a27f5c, 0x3039239f428330c4, 0xa0c4b735ed7dcf98, 0x6e359771ddf6af6a, 0xe986e4cac4584651, 0x8233a2b622d5518, 0xbfd67bf5f06b818b, 0xdffe38d0f5b966a6, 0xa86b36a3272ee00a, 0x193e2ea4f68f}, b: fp751Element{0x5a0f396459d9d998, 0x479f42250b1b7dda, 0x4016b57e2a15bf75, 0xc59f915203fa3749, 0xd5f90257399cf8da, 0x1fb2dadfd86dcef4, 0x600f20e6429021dc, 0x17e347d380c57581, 0xc1b0d5fa8fe3e440, 0xbcf035330ac20e8, 0x50c2eb5f6a4f03e6, 0x86b7c4571}}
	xQ.z.One()

	xPmQ.x = ExtensionFieldElement{a: fp751Element{0x4aafa9f378f7b5ff, 0x1172a683aa8eee0, 0xea518d8cbec2c1de, 0xe191bcbb63674557, 0x97bc19637b259011, 0xdbeae5c9f4a2e454, 0x78f64d1b72a42f95, 0xe71cb4ea7e181e54, 0xe4169d4c48543994, 0x6198c2286a98730f, 0xd21d675bbab1afa5, 0x2e7269fce391}, b: fp751Element{0x23355783ce1d0450, 0x683164cf4ce3d93f, 0xae6d1c4d25970fd8, 0x7807007fb80b48cf, 0xa005a62ec2bbb8a2, 0x6b5649bd016004cb, 0xbb1a13fa1330176b, 0xbf38e51087660461, 0xe577fddc5dd7b930, 0x5f38116f56947cd3, 0x3124f30b98c36fde, 0x4ca9b6e6db37}}
	xPmQ.z.One()

	xR.ThreePointLadder(&curve, &xP, &xQ, &xPmQ, mScalarBytes[:])

	affine_xR := xR.toAffine()

	sageAffine_xR := ExtensionFieldElement{a: fp751Element{0x729465ba800d4fd5, 0x9398015b59e514a1, 0x1a59dd6be76c748e, 0x1a7db94eb28dd55c, 0x444686e680b1b8ec, 0xcc3d4ace2a2454ff, 0x51d3dab4ec95a419, 0xc3b0f33594acac6a, 0x9598a74e7fd44f8a, 0x4fbf8c638f1c2e37, 0x844e347033052f51, 0x6cd6de3eafcf}, b: fp751Element{0x85da145412d73430, 0xd83c0e3b66eb3232, 0xd08ff2d453ec1369, 0xa64aaacfdb395b13, 0xe9cba211a20e806e, 0xa4f80b175d937cfc, 0x556ce5c64b1f7937, 0xb59b39ea2b3fdf7a, 0xc2526b869a4196b3, 0x8dad90bca9371750, 0xdfb4a30c9d9147a2, 0x346d2130629b}}

	if !affine_xR.VartimeEq(&sageAffine_xR) {
		t.Error("\nExpected\n", sageAffine_xR, "\nfound\n", affine_xR)
	}
}

func TestPointTripleVersusAddDouble(t *testing.T) {
	tripleEqualsAddDouble := func(curve ProjectiveCurveParameters, P ProjectivePoint) bool {

		cachedParams := curve.cachedParams()
		var P2, P3, P2plusP ProjectivePoint
		P2.Double(&P, &cachedParams) // = x([2]P)
		P3.Triple(&P, &cachedParams) // = x([3]P)
		P2plusP.Add(&P2, &P, &P)     // = x([2]P + P)

		return P3.VartimeEq(&P2plusP)
	}

	if err := quick.Check(tripleEqualsAddDouble, quickCheckConfig); err != nil {
		t.Error(err)
	}
}

func BenchmarkPointAddition(b *testing.B) {
	var xP = ProjectivePoint{x: curve_A, z: curve_C}
	var xP2, xP3 ProjectivePoint
	cachedParams := curve.cachedParams()
	xP2.Double(&xP, &cachedParams)

	for n := 0; n < b.N; n++ {
		xP3.Add(&xP2, &xP, &xP)
	}
}

func BenchmarkPointDouble(b *testing.B) {
	var xP = ProjectivePoint{x: curve_A, z: curve_C}
	cachedParams := curve.cachedParams()

	for n := 0; n < b.N; n++ {
		xP.Double(&xP, &cachedParams)
	}
}

func BenchmarkPointTriple(b *testing.B) {
	var xP = ProjectivePoint{x: curve_A, z: curve_C}
	cachedParams := curve.cachedParams()

	for n := 0; n < b.N; n++ {
		xP.Triple(&xP, &cachedParams)
	}
}