// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file contains utility functions and types for tests for the security package.

package security

import (
	"bytes"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"fmt"
	"reflect"
	"strings"
	"testing"

	"v.io/v23/context"
	"v.io/v23/uniqueid"
	"v.io/v23/vdl"
	"v.io/v23/vom"
)

type markedRoot struct {
	root    []byte
	pattern BlessingPattern
}

type roots struct {
	data []markedRoot
}

func (r *roots) Add(root []byte, pattern BlessingPattern) error {
	if !pattern.IsValid() {
		return fmt.Errorf("pattern %q is invalid", pattern)
	}
	r.data = append(r.data, markedRoot{root, pattern})
	return nil
}

func (r *roots) Recognized(root []byte, blessing string) error {
	for _, mr := range r.data {
		if bytes.Equal(root, mr.root) && mr.pattern.MatchedBy(blessing) {
			return nil
		}
	}
	key, err := UnmarshalPublicKey(root)
	if err != nil {
		return err
	}
	return NewErrUnrecognizedRoot(nil, key.String(), nil)
}

func (r *roots) Dump() map[BlessingPattern][]PublicKey {
	ret := make(map[BlessingPattern][]PublicKey)
	for _, mr := range r.data {
		key, err := UnmarshalPublicKey(mr.root)
		if err != nil {
			ret[mr.pattern] = append(ret[mr.pattern], key)
		}
	}
	return ret
}

func (*roots) DebugString() string {
	return "BlessingRoots implementation for testing purposes only"
}

func newCaveat(c Caveat, err error) Caveat {
	if err != nil {
		panic(err)
	}
	return c
}

// Caveat that validates iff Call.Suffix matches the string.
//
// Since at the time of this writing, it was not clear that we want to make caveats on
// suffixes generally available, this type is implemented in this test file.
// If there is a general need for such a caveat, it should be defined similar to
// other caveats (like methodCaveat) in caveat.vdl and removed from this test file.
var suffixCaveat = CaveatDescriptor{
	Id:        uniqueid.Id{0xce, 0xc4, 0xd0, 0x98, 0x94, 0x53, 0x90, 0xdb, 0x15, 0x7c, 0xa8, 0x10, 0xae, 0x62, 0x80, 0x0},
	ParamType: vdl.TypeOf(string("")),
}

func newSuffixCaveat(suffix string) Caveat { return newCaveat(NewCaveat(suffixCaveat, suffix)) }

func newECDSASigner(t testing.TB, curve elliptic.Curve) Signer {
	key, err := ecdsa.GenerateKey(curve, rand.Reader)
	if err != nil {
		t.Fatalf("Failed to generate ECDSA key: %v", err)
	}
	return NewInMemoryECDSASigner(key)
}

func newPrincipal(t testing.TB) Principal {
	p, err := CreatePrincipal(newECDSASigner(t, elliptic.P256()), nil, &roots{})
	if err != nil {
		t.Fatalf("CreatePrincipal failed: %v", err)
	}
	return p
}

func blessSelf(t *testing.T, p Principal, name string, caveats ...Caveat) Blessings {
	b, err := p.BlessSelf(name, caveats...)
	if err != nil {
		t.Fatal(err)
	}
	return b
}

func addToRoots(t *testing.T, p Principal, b Blessings) {
	if err := AddToRoots(p, b); err != nil {
		t.Fatal(err)
	}
}

func equalBlessings(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}
	return true
}

func checkBlessings(b Blessings, c CallParams, want ...string) error {
	// Validate the integrity of the bits.
	var decoded Blessings
	if err := roundTrip(b, &decoded); err != nil {
		return err
	}
	if !reflect.DeepEqual(decoded, b) {
		return fmt.Errorf("reflect.DeepEqual of %#v and %#v failed after roundtripping", decoded, b)
	}
	// And now check them under the right call
	c.RemoteBlessings = b
	ctx, cancel := context.RootContext()
	defer cancel()
	got, _ := RemoteBlessingNames(ctx, NewCall(&c))
	if !equalBlessings(got, want) {
		return fmt.Errorf("Got blessings %v, want %v", got, want)
	}
	return nil
}

func matchesError(got error, want string) error {
	if (got == nil) && len(want) == 0 {
		return nil
	}
	if got == nil {
		return fmt.Errorf("Got nil error, wanted to match %q", want)
	}
	if !strings.Contains(got.Error(), want) {
		return fmt.Errorf("Got error %q, wanted to match %q", got, want)
	}
	return nil
}

func roundTrip(in, out interface{}) error {
	data, err := vom.Encode(in)
	if err != nil {
		return err
	}
	return vom.Decode(data, out)
}

func init() {
	RegisterCaveatValidator(suffixCaveat, func(ctx *context.T, call Call, suffix string) error {
		if suffix != call.Suffix() {
			return fmt.Errorf("suffixCaveat not met")
		}
		return nil
	})
}