// Copyright (c) 2013-2017 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

package txscript

import (
	"bytes"
	"reflect"
	"testing"

	"github.com/daglabs/btcd/dagconfig"
	"github.com/daglabs/btcd/util"
)

// mustParseShortForm parses the passed short form script and returns the
// resulting bytes.  It panics if an error occurs.  This is only used in the
// tests as a helper since the only way it can fail is if there is an error in
// the test source code.
func mustParseShortForm(script string) []byte {
	s, err := parseShortForm(script)
	if err != nil {
		panic("invalid short form script in test source: err " +
			err.Error() + ", script: " + script)
	}

	return s
}

// newAddressPubKeyHash returns a new util.AddressPubKeyHash from the
// provided hash.  It panics if an error occurs.  This is only used in the tests
// as a helper since the only way it can fail is if there is an error in the
// test source code.
func newAddressPubKeyHash(pkHash []byte) util.Address {
	addr, err := util.NewAddressPubKeyHash(pkHash, util.Bech32PrefixDAGCoin)
	if err != nil {
		panic("invalid public key hash in test source")
	}

	return addr
}

// newAddressScriptHash returns a new util.AddressScriptHash from the
// provided hash.  It panics if an error occurs.  This is only used in the tests
// as a helper since the only way it can fail is if there is an error in the
// test source code.
func newAddressScriptHash(scriptHash []byte) util.Address {
	addr, err := util.NewAddressScriptHashFromHash(scriptHash,
		util.Bech32PrefixDAGCoin)
	if err != nil {
		panic("invalid script hash in test source")
	}

	return addr
}

// TestExtractPkScriptAddrs ensures that extracting the type, addresses, and
// number of required signatures from PkScripts works as intended.
func TestExtractPkScriptAddrs(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name    string
		script  []byte
		addrs   []util.Address
		reqSigs int
		class   ScriptClass
	}{
		{
			name: "standard p2pkh",
			script: hexToBytes("76a914ad06dd6ddee55cbca9a9e3713bd" +
				"7587509a3056488ac"),
			addrs: []util.Address{
				newAddressPubKeyHash(hexToBytes("ad06dd6ddee5" +
					"5cbca9a9e3713bd7587509a30564")),
			},
			reqSigs: 1,
			class:   PubKeyHashTy,
		},
		{
			name: "standard p2sh",
			script: hexToBytes("a91463bcc565f9e68ee0189dd5cc67f1b" +
				"0e5f02f45cb87"),
			addrs: []util.Address{
				newAddressScriptHash(hexToBytes("63bcc565f9e6" +
					"8ee0189dd5cc67f1b0e5f02f45cb")),
			},
			reqSigs: 1,
			class:   ScriptHashTy,
		},

		// The below are nonstandard script due to things such as
		// invalid pubkeys, failure to parse, and not being of a
		// standard form.

		{
			name: "p2pk with uncompressed pk missing OP_CHECKSIG",
			script: hexToBytes("410411db93e1dcdb8a016b49840f8c53b" +
				"c1eb68a382e97b1482ecad7b148a6909a5cb2e0eaddf" +
				"b84ccf9744464f82e160bfa9b8b64f9d4c03f999b864" +
				"3f656b412a3"),
			addrs:   nil,
			reqSigs: 0,
			class:   NonStandardTy,
		},
		{
			name: "valid signature from a sigscript - no addresses",
			script: hexToBytes("47304402204e45e16932b8af514961a1d" +
				"3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd41022" +
				"0181522ec8eca07de4860a4acdd12909d831cc56cbba" +
				"c4622082221a8768d1d0901"),
			addrs:   nil,
			reqSigs: 0,
			class:   NonStandardTy,
		},
		// Note the technically the pubkey is the second item on the
		// stack, but since the address extraction intentionally only
		// works with standard PkScripts, this should not return any
		// addresses.
		{
			name: "valid sigscript to reedeem p2pk - no addresses",
			script: hexToBytes("493046022100ddc69738bf2336318e4e0" +
				"41a5a77f305da87428ab1606f023260017854350ddc0" +
				"22100817af09d2eec36862d16009852b7e3a0f6dd765" +
				"98290b7834e1453660367e07a014104cd4240c198e12" +
				"523b6f9cb9f5bed06de1ba37e96a1bbd13745fcf9d11" +
				"c25b1dff9a519675d198804ba9962d3eca2d5937d58e" +
				"5a75a71042d40388a4d307f887d"),
			addrs:   nil,
			reqSigs: 0,
			class:   NonStandardTy,
		},
		{
			name:    "empty script",
			script:  []byte{},
			addrs:   nil,
			reqSigs: 0,
			class:   NonStandardTy,
		},
		{
			name:    "script that does not parse",
			script:  []byte{OpData45},
			addrs:   nil,
			reqSigs: 0,
			class:   NonStandardTy,
		},
	}

	t.Logf("Running %d tests.", len(tests))
	for i, test := range tests {
		class, addrs, reqSigs, err := ExtractPkScriptAddrs(
			test.script, &dagconfig.MainNetParams)
		if err != nil {
		}

		if !reflect.DeepEqual(addrs, test.addrs) {
			t.Errorf("ExtractPkScriptAddrs #%d (%s) unexpected "+
				"addresses\ngot  %v\nwant %v", i, test.name,
				addrs, test.addrs)
			continue
		}

		if reqSigs != test.reqSigs {
			t.Errorf("ExtractPkScriptAddrs #%d (%s) unexpected "+
				"number of required signatures - got %d, "+
				"want %d", i, test.name, reqSigs, test.reqSigs)
			continue
		}

		if class != test.class {
			t.Errorf("ExtractPkScriptAddrs #%d (%s) unexpected "+
				"script type - got %s, want %s", i, test.name,
				class, test.class)
			continue
		}
	}
}

// TestCalcScriptInfo ensures the CalcScriptInfo provides the expected results
// for various valid and invalid script pairs.
func TestCalcScriptInfo(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name      string
		sigScript string
		pkScript  string

		isP2SH bool

		scriptInfo    ScriptInfo
		scriptInfoErr error
	}{
		{
			// Invented scripts, the hashes do not match
			// Truncated version of test below:
			name: "pkscript doesn't parse",
			sigScript: "1 81 DATA_8 2DUP EQUAL NOT VERIFY ABS " +
				"SWAP ABS EQUAL",
			pkScript: "HASH160 DATA_20 0xfe441065b6532231de2fac56" +
				"3152205ec4f59c",
			isP2SH:        true,
			scriptInfoErr: scriptError(ErrMalformedPush, ""),
		},
		{
			name: "sigScript doesn't parse",
			// Truncated version of p2sh script below.
			sigScript: "1 81 DATA_8 2DUP EQUAL NOT VERIFY ABS " +
				"SWAP ABS",
			pkScript: "HASH160 DATA_20 0xfe441065b6532231de2fac56" +
				"3152205ec4f59c74 EQUAL",
			isP2SH:        true,
			scriptInfoErr: scriptError(ErrMalformedPush, ""),
		},
		{
			// Invented scripts, the hashes do not match
			name: "p2sh standard script",
			sigScript: "1 81 DATA_25 DUP HASH160 DATA_20 0x010203" +
				"0405060708090a0b0c0d0e0f1011121314 EQUALVERIFY " +
				"CHECKSIG",
			pkScript: "HASH160 DATA_20 0xfe441065b6532231de2fac56" +
				"3152205ec4f59c74 EQUAL",
			isP2SH: true,
			scriptInfo: ScriptInfo{
				PkScriptClass:  ScriptHashTy,
				NumInputs:      3,
				ExpectedInputs: 3, // nonstandard p2sh.
				SigOps:         1,
			},
		},
		{
			// from 567a53d1ce19ce3d07711885168484439965501536d0d0294c5d46d46c10e53b
			// from the blockchain.
			name: "p2sh nonstandard script",
			sigScript: "1 81 DATA_8 2DUP EQUAL NOT VERIFY ABS " +
				"SWAP ABS EQUAL",
			pkScript: "HASH160 DATA_20 0xfe441065b6532231de2fac56" +
				"3152205ec4f59c74 EQUAL",
			isP2SH: true,
			scriptInfo: ScriptInfo{
				PkScriptClass:  ScriptHashTy,
				NumInputs:      3,
				ExpectedInputs: -1, // nonstandard p2sh.
				SigOps:         0,
			},
		},
	}

	for _, test := range tests {
		sigScript := mustParseShortForm(test.sigScript)
		pkScript := mustParseShortForm(test.pkScript)

		si, err := CalcScriptInfo(sigScript, pkScript, test.isP2SH)
		if e := checkScriptError(err, test.scriptInfoErr); e != nil {
			t.Errorf("scriptinfo test %q: %v", test.name, e)
			continue
		}
		if err != nil {
			continue
		}

		if *si != test.scriptInfo {
			t.Errorf("%s: scriptinfo doesn't match expected. "+
				"got: %q expected %q", test.name, *si,
				test.scriptInfo)
			continue
		}
	}
}

// bogusAddress implements the util.Address interface so the tests can ensure
// unsupported address types are handled properly.
type bogusAddress struct{}

// EncodeAddress simply returns an empty string.  It exists to satisfy the
// util.Address interface.
func (b *bogusAddress) EncodeAddress() string {
	return ""
}

// ScriptAddress simply returns an empty byte slice.  It exists to satisfy the
// util.Address interface.
func (b *bogusAddress) ScriptAddress() []byte {
	return nil
}

// IsForPrefix lies blatantly to satisfy the util.Address interface.
func (b *bogusAddress) IsForPrefix(prefix util.Bech32Prefix) bool {
	return true // why not?
}

// String simply returns an empty string.  It exists to satisfy the
// util.Address interface.
func (b *bogusAddress) String() string {
	return ""
}

// TestPayToAddrScript ensures the PayToAddrScript function generates the
// correct scripts for the various types of addresses.
func TestPayToAddrScript(t *testing.T) {
	t.Parallel()

	// 1MirQ9bwyQcGVJPwKUgapu5ouK2E2Ey4gX
	p2pkhMain, err := util.NewAddressPubKeyHash(hexToBytes("e34cce70c86"+
		"373273efcc54ce7d2a491bb4a0e84"), util.Bech32PrefixDAGCoin)
	if err != nil {
		t.Fatalf("Unable to create public key hash address: %v", err)
	}

	// Taken from transaction:
	// b0539a45de13b3e0403909b8bd1a555b8cbe45fd4e3f3fda76f3a5f52835c29d
	p2shMain, _ := util.NewAddressScriptHashFromHash(hexToBytes("e8c300"+
		"c87986efa84c37c0519929019ef86eb5b4"), util.Bech32PrefixDAGCoin)
	if err != nil {
		t.Fatalf("Unable to create script hash address: %v", err)
	}

	// Errors used in the tests below defined here for convenience and to
	// keep the horizontal test size shorter.
	errUnsupportedAddress := scriptError(ErrUnsupportedAddress, "")

	tests := []struct {
		in       util.Address
		expected string
		err      error
	}{
		// pay-to-pubkey-hash address on mainnet
		{
			p2pkhMain,
			"DUP HASH160 DATA_20 0xe34cce70c86373273efcc54ce7d2a4" +
				"91bb4a0e8488 CHECKSIG",
			nil,
		},
		// pay-to-script-hash address on mainnet
		{
			p2shMain,
			"HASH160 DATA_20 0xe8c300c87986efa84c37c0519929019ef8" +
				"6eb5b4 EQUAL",
			nil,
		},

		// Supported address types with nil pointers.
		{(*util.AddressPubKeyHash)(nil), "", errUnsupportedAddress},
		{(*util.AddressScriptHash)(nil), "", errUnsupportedAddress},

		// Unsupported address type.
		{&bogusAddress{}, "", errUnsupportedAddress},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		pkScript, err := PayToAddrScript(test.in)
		if e := checkScriptError(err, test.err); e != nil {
			t.Errorf("PayToAddrScript #%d unexpected error - "+
				"got %v, want %v", i, err, test.err)
			continue
		}

		expected := mustParseShortForm(test.expected)
		if !bytes.Equal(pkScript, expected) {
			t.Errorf("PayToAddrScript #%d got: %x\nwant: %x",
				i, pkScript, expected)
			continue
		}
	}
}

// scriptClassTests houses several test scripts used to ensure various class
// determination is working as expected.  It's defined as a test global versus
// inside a function scope since this spans both the standard tests and the
// consensus tests (pay-to-script-hash is part of consensus).
var scriptClassTests = []struct {
	name   string
	script string
	class  ScriptClass
}{
	// p2pk. It is standard in BTC but not in DAGCoin
	{
		name: "Pay Pubkey",
		script: "DATA_65 0x0411db93e1dcdb8a016b49840f8c53bc1eb68a382e" +
			"97b1482ecad7b148a6909a5cb2e0eaddfb84ccf9744464f82e16" +
			"0bfa9b8b64f9d4c03f999b8643f656b412a3 CHECKSIG",
		class: NonStandardTy,
	},
	// tx 599e47a8114fe098103663029548811d2651991b62397e057f0c863c2bc9f9ea
	{
		name: "Pay PubkeyHash",
		script: "DUP HASH160 DATA_20 0x660d4ef3a743e3e696ad990364e555" +
			"c271ad504b EQUALVERIFY CHECKSIG",
		class: PubKeyHashTy,
	},
	// mutlisig. It is standard in BTC but not in DAGCoin
	{
		name: "multisig",
		script: "1 DATA_33 0x0232abdc893e7f0631364d7fd01cb33d24da4" +
			"5329a00357b3a7886211ab414d55a 1 CHECKMULTISIG",
		class: NonStandardTy,
	},
	// tx e5779b9e78f9650debc2893fd9636d827b26b4ddfa6a8172fe8708c924f5c39d
	{
		name: "P2SH",
		script: "HASH160 DATA_20 0x433ec2ac1ffa1b7b7d027f564529c57197f" +
			"9ae88 EQUAL",
		class: ScriptHashTy,
	},

	{
		// Nulldata. It is standard in BTC but not in DAGCoin
		name:   "nulldata",
		script: "RETURN 0",
		class:  NonStandardTy,
	},

	// The next few are almost multisig (it is the more complex script type)
	// but with various changes to make it fail.
	{
		// Multisig but invalid nsigs.
		name: "strange 1",
		script: "DUP DATA_33 0x0232abdc893e7f0631364d7fd01cb33d24da45" +
			"329a00357b3a7886211ab414d55a 1 CHECKMULTISIG",
		class: NonStandardTy,
	},
	{
		// Multisig but invalid pubkey.
		name:   "strange 2",
		script: "1 1 1 CHECKMULTISIG",
		class:  NonStandardTy,
	},
	{
		// Multisig but no matching npubkeys opcode.
		name: "strange 3",
		script: "1 DATA_33 0x0232abdc893e7f0631364d7fd01cb33d24da4532" +
			"9a00357b3a7886211ab414d55a DATA_33 0x0232abdc893e7f0" +
			"631364d7fd01cb33d24da45329a00357b3a7886211ab414d55a " +
			"CHECKMULTISIG",
		class: NonStandardTy,
	},
	{
		// Multisig but with multisigverify.
		name: "strange 4",
		script: "1 DATA_33 0x0232abdc893e7f0631364d7fd01cb33d24da4532" +
			"9a00357b3a7886211ab414d55a 1 CHECKMULTISIGVERIFY",
		class: NonStandardTy,
	},
	{
		// Multisig but wrong length.
		name:   "strange 5",
		script: "1 CHECKMULTISIG",
		class:  NonStandardTy,
	},
	{
		name:   "doesn't parse",
		script: "DATA_5 0x01020304",
		class:  NonStandardTy,
	},
	{
		name: "multisig script with wrong number of pubkeys",
		script: "2 " +
			"DATA_33 " +
			"0x027adf5df7c965a2d46203c781bd4dd8" +
			"21f11844136f6673af7cc5a4a05cd29380 " +
			"DATA_33 " +
			"0x02c08f3de8ee2de9be7bd770f4c10eb0" +
			"d6ff1dd81ee96eedd3a9d4aeaf86695e80 " +
			"3 CHECKMULTISIG",
		class: NonStandardTy,
	},
}

// TestScriptClass ensures all the scripts in scriptClassTests have the expected
// class.
func TestScriptClass(t *testing.T) {
	t.Parallel()

	for _, test := range scriptClassTests {
		script := mustParseShortForm(test.script)
		class := GetScriptClass(script)
		if class != test.class {
			t.Errorf("%s: expected %s got %s (script %x)", test.name,
				test.class, class, script)
			continue
		}
	}
}

// TestStringifyClass ensures the script class string returns the expected
// string for each script class.
func TestStringifyClass(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name     string
		class    ScriptClass
		stringed string
	}{
		{
			name:     "nonstandardty",
			class:    NonStandardTy,
			stringed: "nonstandard",
		},
		{
			name:     "pubkeyhash",
			class:    PubKeyHashTy,
			stringed: "pubkeyhash",
		},
		{
			name:     "scripthash",
			class:    ScriptHashTy,
			stringed: "scripthash",
		},
		{
			name:     "broken",
			class:    ScriptClass(255),
			stringed: "Invalid",
		},
	}

	for _, test := range tests {
		typeString := test.class.String()
		if typeString != test.stringed {
			t.Errorf("%s: got %#q, want %#q", test.name,
				typeString, test.stringed)
		}
	}
}