//go:build ignore

// Prints src/lib/dkc/testing/capsule-vectors.json: the verdicts of the Go
// reference on what scripts/capsule-ts-samples.mjs wrote with the writer of
// this repository (plan of phase 3, decision 11 and section 8, point 9):
//
//   - samples: each .dkc, of format 2 or 3, is inspected with capsule.Inspect
//     and opened with capsule.Open and the published signature of its round,
//     with each credential alone and with all of them, and the verdict, the
//     format, L, the padding rule and P are recorded; in format 2 the SHA-256
//     of the content, and in format 3 the files that a Sink receives, with
//     their SHA-256, the head encoded again with capsule.EncodeHead, the
//     verdicts of the security area and the size of the area. Its
//     PUBLIC_HEADER, its CONTROL_CBOR, opened layer by layer with the
//     identities of agewrap, and its .dkk are encoded again by the reference
//     and compared with the bytes written, the public note that
//     Header.PublicNote reads in its PUBLIC_HEADER is recorded, null without
//     one, and so is the number of stanzas of its INNER_ACCESS_AGE.
//   - mixes: the code and the step at which capsule.Open fails.
//   - encoders: capsule.EncodeHeader, capsule.EncodeControl (format 2) and
//     AccessKey.MarshalBody on every input, compared with the bytes of the
//     TypeScript library.
//   - recipients: age.ParseX25519Recipient, then agewrap.CheckX25519Recipient,
//     on every string.
//   - errors: the text of capsule.Encrypt for each invalid option, as a
//     generator of test vectors, the only writer of format 2 (spec §62.1
//     rule 1).
//   - note_errors: the text of capsule.EncryptFiles for each public note that
//     breaks the rules of spec §24.1.
//
// Run it from a scratch module that requires the reference implementation
// (replace g.activething.com/go/DateKeys => ../datekeys-go, GOFLAGS=-mod=mod
// and the go directive of the reference, so that its toolchain is used),
// passing the output of capsule-ts-samples.mjs:
//
//	go run capsule-go-verdicts.go ts-samples.json > capsule-vectors.json
package main

import (
	"bytes"
	"context"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"maps"
	"os"
	"runtime/debug"
	"slices"
	"strings"
	"time"

	"filippo.io/age"
	datekeys "g.activething.com/go/DateKeys"
	"g.activething.com/go/DateKeys/accesskey"
	"g.activething.com/go/DateKeys/agewrap"
	"g.activething.com/go/DateKeys/capsule"
	"g.activething.com/go/DateKeys/codec/bech32"
	"g.activething.com/go/DateKeys/datekey"
	"g.activething.com/go/DateKeys/extension"
	"g.activething.com/go/DateKeys/profile"
	"g.activething.com/go/DateKeys/provider"
)

// The published Quicknet signatures of the rounds of the samples, as in the
// fixtures; provider.Verify checks them in capsule.Open.
var published = map[uint64]string{
	1000: "b44679b9a59af2ec876b1a6b1ad52ea9b1615fc3982b19576350f93447cb1125e342b73a8dd2bacbe47e4b6b63ed5e39",
	1001: "b33bf3667cbd5a82de3a24b4e0e9fe5513cc1a0e840368c6e31f5fcfa79bea03f73896b25883abf2853d10337fb8fa41",
	2000: "b6cb8f482a0b15d45936a4c4ea08e98a087e71787caee3f4d07a8a9843b1bc5423c6b3c22f446488b3137eaca799c77e",
}

type extJSON struct {
	ID      string  `json:"id"`
	Version uint64  `json:"version"`
	Data    *string `json:"data,omitempty"`
}

type sampleIn struct {
	Name         string `json:"name"`
	Round        uint64 `json:"round"`
	Policy       string `json:"policy"`
	Format       int    `json:"format"`
	Length       uint64 `json:"length"`
	Padding      int    `json:"padding"`
	PaddedLength uint64 `json:"padded_length"`
	// Format 2: the SHA-256 of the content. Format 3: the head written and
	// its files.
	ContentSHA256 string     `json:"content_sha256,omitempty"`
	HeadCBOR      string     `json:"head_cbor,omitempty"`
	Files         []fileJSON `json:"files,omitempty"`
	Identities    []string   `json:"identities"`
	DKK           string     `json:"dkk,omitempty"`
	Known         []extJSON  `json:"known"`
	// PublicNote is the public note that the writer was given, if any.
	PublicNote *string `json:"public_note,omitempty"`
	DKC        string  `json:"dkc"`
}

// A file of a format 3 capsule: its path, size, SHA-256 and mtime.
type fileJSON struct {
	Path   string  `json:"path"`
	Size   uint64  `json:"size"`
	SHA256 string  `json:"sha256"`
	MTime  *uint64 `json:"mtime,omitempty"`
}

type encoderIn struct {
	Header struct {
		CapsuleID   string    `json:"capsule_id"`
		Round       uint64    `json:"round"`
		Policy      int       `json:"policy"`
		Critical    []extJSON `json:"critical"`
		Noncritical []extJSON `json:"noncritical"`
	} `json:"header"`
	Control struct {
		HeaderBinding   string    `json:"header_binding"`
		PayloadIdentity string    `json:"payload_identity"`
		PayloadLength   uint64    `json:"payload_length"`
		Padding         int       `json:"padding"`
		Critical        []extJSON `json:"critical"`
		Noncritical     []extJSON `json:"noncritical"`
	} `json:"control"`
	DKK struct {
		CredentialID  string    `json:"credential_id"`
		CapsuleID     string    `json:"capsule_id"`
		Material      string    `json:"material"`
		CapsuleDigest *string   `json:"capsule_digest,omitempty"`
		Critical      []extJSON `json:"critical"`
		Noncritical   []extJSON `json:"noncritical"`
	} `json:"dkk"`
	HeaderCBOR  string `json:"header_cbor"`
	ControlCBOR string `json:"control_cbor"`
	DKKBody     string `json:"dkk_body"`
}

type errorCase struct {
	Name               string    `json:"name"`
	Policy             int       `json:"policy"`
	Recipients         []string  `json:"recipients,omitempty"`
	Portable           bool      `json:"portable,omitempty"`
	UnlockAt           string    `json:"unlock_at"`
	Now                string    `json:"now"`
	Length             int64     `json:"length"`
	Padding            int       `json:"padding,omitempty"`
	Critical           []extJSON `json:"critical,omitempty"`
	Noncritical        []extJSON `json:"noncritical,omitempty"`
	ControlCritical    []extJSON `json:"control_critical,omitempty"`
	ControlNoncritical []extJSON `json:"control_noncritical,omitempty"`
	ChainHashFlip      bool      `json:"chain_hash_flip,omitempty"`
	PublicNote         string    `json:"public_note,omitempty"`
	TS                 string    `json:"ts"`
	Go                 string    `json:"go"`
}

// noteError is a public note that breaks the rules of spec §24.1, and the
// texts of capsule.EncryptFiles and of the TypeScript library for it.
type noteError struct {
	Name string `json:"name"`
	Note string `json:"note"`
	TS   string `json:"ts"`
	Go   string `json:"go"`
}

type input struct {
	Generator string     `json:"generator"`
	Samples   []sampleIn `json:"samples"`
	Mixes     []struct {
		Name  string `json:"name"`
		Round uint64 `json:"round"`
		DKC   string `json:"dkc"`
	} `json:"mixes"`
	Encoders struct {
		Seed   int         `json:"seed"`
		Count  int         `json:"count"`
		SHA256 string      `json:"sha256"`
		Cases  []encoderIn `json:"cases"`
	} `json:"encoders"`
	Recipients []string    `json:"recipients"`
	Errors     []errorCase `json:"errors"`
	NoteErrors []noteError `json:"note_errors"`
}

// The verdict of one opening: "ok" with what was delivered, or the code and
// the step of the failure.
type openVerdict struct {
	Credentials string     `json:"credentials"`
	Result      string     `json:"result"`
	Step        int        `json:"step,omitempty"`
	Opened      *openedOut `json:"opened,omitempty"`
}

type openedOut struct {
	ContentSHA256 string     `json:"content_sha256,omitempty"`
	Format        int        `json:"format"`
	Length        uint64     `json:"length"`
	Padding       int        `json:"padding"`
	PaddedLength  uint64     `json:"padded_length"`
	Files         []fileJSON `json:"files,omitempty"`
	HeadCBOR      string     `json:"head_cbor,omitempty"`
	Verdicts      []string   `json:"verdicts,omitempty"`
	AreaLen       uint32     `json:"area_len,omitempty"`
}

// sink keeps the files of a format 3 capsule in memory.
type sink struct {
	files []*bytes.Buffer
}

type buffer struct{ *bytes.Buffer }

func (buffer) Close() error { return nil }

func (s *sink) Begin(*capsule.Head) error { return nil }
func (s *sink) Create(int) (io.WriteCloser, error) {
	b := &bytes.Buffer{}
	s.files = append(s.files, b)
	return buffer{b}, nil
}
func (s *sink) Commit() error { return nil }
func (s *sink) Abort()        { s.files = nil }

type sampleOut struct {
	sampleIn
	Go struct {
		Inspect      string        `json:"inspect"`
		Opens        []openVerdict `json:"opens"`
		InnerStanzas int           `json:"inner_stanzas"`
		Reencoded    bool          `json:"reencoded"`
		PublicNote   *string       `json:"public_note"`
	} `json:"go"`
}

type mixOut struct {
	Name  string `json:"name"`
	Round uint64 `json:"round"`
	DKC   string `json:"dkc"`
	Go    struct {
		Code string `json:"code"`
		Step int    `json:"step"`
	} `json:"go"`
}

type recipientOut struct {
	String string `json:"string"`
	Parse  string `json:"parse"`
	Check  string `json:"check,omitempty"`
}

type output struct {
	Description      string         `json:"description"`
	Generator        string         `json:"generator"`
	SamplesGenerator string         `json:"samples_generator"`
	Libraries        string         `json:"libraries"`
	Releases         []releaseOut   `json:"releases"`
	Samples          []sampleOut    `json:"samples"`
	Mixes            []mixOut       `json:"mixes"`
	Encoders         encodersOut    `json:"encoders"`
	Recipients       []recipientOut `json:"recipients"`
	Errors           []errorCase    `json:"errors"`
	NoteErrors       []noteError    `json:"note_errors"`
}

type releaseOut struct {
	Round     uint64 `json:"round"`
	Signature string `json:"signature"`
}

type encodersOut struct {
	Seed        int      `json:"seed"`
	Count       int      `json:"count"`
	SHA256      string   `json:"sha256"`
	Equal       int      `json:"equal"`
	Differences []string `json:"differences"`
}

func must[T any](v T, err error) T {
	if err != nil {
		panic(err)
	}
	return v
}

func unhex(s string) []byte { return must(hex.DecodeString(s)) }

func exts(list []extJSON) []extension.Extension {
	var out []extension.Extension
	for _, e := range list {
		x := extension.Extension{ID: e.ID, Version: e.Version}
		if e.Data != nil {
			x.Data = unhex(*e.Data)
			if x.Data == nil {
				x.Data = []byte{}
			}
		}
		out = append(out, x)
	}
	return out
}

func source(round uint64) provider.ReleaseSource {
	return provider.ReleaseSourceFunc(func(_ context.Context, _ *profile.Profile, c provider.Condition) (provider.Release, error) {
		return provider.Release{Round: c.Round, Signature: unhex(published[c.Round])}, nil
	})
}

func opened(dkc []byte, round uint64, reg profile.Registry, ex extension.Registry, ids []age.Identity, dkk []byte) openVerdict {
	var out bytes.Buffer
	files := &sink{}
	o := capsule.OpenOptions{Registry: reg, Extensions: ex, Source: source(round), Identities: ids, Sink: files, Now: func() time.Time {
		return time.Unix(1692803367+int64(round-1)*3, 0)
	}}
	if dkk != nil {
		o.AccessKeyFile = bytes.NewReader(dkk)
	}
	res, err := capsule.Open(context.Background(), &out, bytes.NewReader(dkc), o)
	v := openVerdict{Result: "ok"}
	if err != nil {
		v.Result = datekeys.Code(err)
		if v.Result == "" {
			v.Result = "error: " + err.Error()
		}
		if res != nil && res.Inspection != nil && len(res.Inspection.Checks) > 0 {
			v.Step = res.Inspection.Checks[len(res.Inspection.Checks)-1].Step
		}
		return v
	}
	v.Opened = &openedOut{Format: int(res.Format), Length: res.PayloadLength, Padding: int(res.Padding), PaddedLength: res.PaddedLength}
	if res.Format != capsule.Format3 {
		sum := sha256.Sum256(out.Bytes())
		v.Opened.ContentSHA256 = hex.EncodeToString(sum[:])
		return v
	}
	for i, f := range res.Head.Files {
		sum := sha256.Sum256(files.files[i].Bytes())
		fj := fileJSON{Path: f.Path, Size: f.Size, SHA256: hex.EncodeToString(sum[:])}
		if f.HasMTime {
			mtime := f.MTime
			fj.MTime = &mtime
		}
		v.Opened.Files = append(v.Opened.Files, fj)
	}
	v.Opened.HeadCBOR = hex.EncodeToString(must(capsule.EncodeHead(res.Head)))
	v.Opened.Verdicts = []string{string(res.Verdicts.Signature), string(res.Verdicts.Seal)}
	v.Opened.AreaLen = res.AreaLen
	return v
}

func main() {
	var in input
	must(0, json.Unmarshal(must(os.ReadFile(os.Args[1])), &in))
	reg := must(profile.Default())
	p := profile.Quicknet()
	out := output{
		Description:      "Verdicts of the Go reference on capsules, mixes, encodings, recipients and invalid options of the TypeScript writer (plan of phase 3, section 8, point 9); see the header of scripts/capsule-go-verdicts.go.",
		Generator:        "scripts/capsule-go-verdicts.go",
		SamplesGenerator: in.Generator,
		Libraries:        libraries(),
	}
	for _, r := range slices.Sorted(maps.Keys(published)) {
		out.Releases = append(out.Releases, releaseOut{r, published[r]})
	}

	for _, s := range in.Samples {
		dkc := unhex(s.DKC)
		known := extension.Set{}
		for _, k := range s.Known {
			known[k.ID] = append(known[k.ID], k.Version)
		}
		so := sampleOut{sampleIn: s}
		if _, err := capsule.Inspect(bytes.NewReader(dkc), capsule.InspectOptions{Registry: reg, Extensions: known}); err != nil {
			so.Go.Inspect = datekeys.Code(err)
		} else {
			so.Go.Inspect = "ok"
		}
		var ids []age.Identity
		for i, raw := range s.Identities {
			id := must(agewrap.X25519IdentityFromRaw(unhex(raw)))
			ids = append(ids, id)
			v := opened(dkc, s.Round, reg, known, []age.Identity{id}, nil)
			v.Credentials = fmt.Sprintf("identity %d", i)
			so.Go.Opens = append(so.Go.Opens, v)
		}
		var dkk []byte
		if s.DKK != "" {
			dkk = unhex(s.DKK)
			v := opened(dkc, s.Round, reg, known, nil, dkk)
			v.Credentials = ".dkk"
			so.Go.Opens = append(so.Go.Opens, v)
		}
		v := opened(dkc, s.Round, reg, known, ids, dkk)
		v.Credentials = "all"
		if ids == nil && dkk == nil {
			v.Credentials = "none"
		}
		so.Go.Opens = append(so.Go.Opens, v)
		so.Go.InnerStanzas, so.Go.Reencoded, so.Go.PublicNote = layers(dkc, s, p, dkk)
		out.Samples = append(out.Samples, so)
	}

	for _, m := range in.Mixes {
		v := opened(unhex(m.DKC), m.Round, reg, extension.Set{}, nil, nil)
		mo := mixOut{Name: m.Name, Round: m.Round, DKC: m.DKC}
		mo.Go.Code, mo.Go.Step = v.Result, v.Step
		out.Mixes = append(out.Mixes, mo)
	}

	out.Encoders = encodersOut{Seed: in.Encoders.Seed, Count: in.Encoders.Count, SHA256: in.Encoders.SHA256, Differences: []string{}}
	for i, c := range in.Encoders.Cases {
		if d := encoders(c); d != "" {
			out.Encoders.Differences = append(out.Encoders.Differences, fmt.Sprintf("case %d: %s", i, d))
		} else {
			out.Encoders.Equal++
		}
	}

	for _, s := range in.Recipients {
		r := recipientOut{String: s, Parse: "ok"}
		x, err := age.ParseX25519Recipient(s)
		if err != nil {
			r.Parse = err.Error()
		} else if err := agewrap.CheckX25519Recipient(x); err != nil {
			r.Check = err.Error()
		} else {
			r.Check = "ok"
		}
		out.Recipients = append(out.Recipients, r)
	}

	for _, c := range in.Errors {
		c.Go = encryptError(c)
		out.Errors = append(out.Errors, c)
	}

	for _, c := range in.NoteErrors {
		c.Go = noteText(c.Note)
		out.NoteErrors = append(out.NoteErrors, c)
	}

	enc := json.NewEncoder(os.Stdout)
	enc.SetIndent("", " ")
	must(0, enc.Encode(out))
}

// layers opens SEALED_CONTROL of a sample with the published release and, in
// time_and_key, with its first credential, and encodes PUBLIC_HEADER,
// CONTROL_CBOR and the .dkk again. It returns the number of stanzas of
// INNER_ACCESS_AGE, whether every encoding equals the bytes written, and the
// public note of PUBLIC_HEADER, nil when there is none that is usable.
func layers(dkc []byte, s sampleIn, p *profile.Profile, dkk []byte) (int, bool, *string) {
	pre := must(capsule.ParsePrelude(dkc))
	header := dkc[capsule.PreludeSize : capsule.PreludeSize+int(pre.PublicHeaderLen)]
	sealed := dkc[capsule.PreludeSize+int(pre.PublicHeaderLen) : capsule.PreludeSize+int(pre.PublicHeaderLen)+int(pre.SealedControlLen)]
	same := true
	h := must(capsule.DecodeHeader(header))
	same = same && bytes.Equal(must(capsule.EncodeHeader(h)), header)
	var note *string
	if text, ok := h.PublicNote(); ok {
		note = &text
	}

	tid := must(agewrap.NewTimeIdentity(p, s.Round, provider.Release{Round: s.Round, Signature: unhex(published[s.Round])}))
	inner := must(io.ReadAll(must(age.Decrypt(bytes.NewReader(sealed), tid))))
	control := inner
	stanzas := 0
	if s.Policy == "time_and_key" {
		st := must(agewrap.Stanzas(bytes.NewReader(inner)))
		stanzas = len(st)
		var id age.Identity
		if len(s.Identities) > 0 {
			id = must(agewrap.X25519IdentityFromRaw(unhex(s.Identities[0])))
		} else {
			k := must(accesskey.Decode(bytes.NewReader(dkk)))
			id = must(agewrap.X25519IdentityFromRaw(k.Material))
		}
		aid := must(agewrap.NewAccessIdentity(agewrap.AccessSlots, id))
		control = must(io.ReadAll(must(age.Decrypt(bytes.NewReader(inner), aid))))
	}
	c := must(capsule.DecodeControl(control, pre.Format))
	same = same && bytes.Equal(must(capsule.EncodeControl(c, pre.Format)), control)
	if dkk != nil {
		k := must(accesskey.Decode(bytes.NewReader(dkk)))
		var b bytes.Buffer
		must(0, accesskey.Encode(&b, k))
		same = same && bytes.Equal(b.Bytes(), dkk)
	}
	return stanzas, same, note
}

// encoders encodes one input with the reference and names the first encoding
// that differs from the bytes of the TypeScript library, or returns "".
func encoders(c encoderIn) string {
	var h capsule.Header
	copy(h.CapsuleID[:], unhex(c.Header.CapsuleID))
	h.DateKey = datekey.DateKey{ProfileID: "datekeys:quicknet:v1", Round: c.Header.Round}
	h.Policy = capsule.Policy(c.Header.Policy)
	h.Critical, h.Noncritical = exts(c.Header.Critical), exts(c.Header.Noncritical)
	hb, err := capsule.EncodeHeader(&h)
	if err != nil || hex.EncodeToString(hb) != c.HeaderCBOR {
		return fmt.Sprintf("PUBLIC_HEADER (%v)", err)
	}
	var ctrl capsule.Control
	copy(ctrl.HeaderBinding[:], unhex(c.Control.HeaderBinding))
	copy(ctrl.PayloadIdentity[:], unhex(c.Control.PayloadIdentity))
	ctrl.PayloadLength, ctrl.Padding = c.Control.PayloadLength, capsule.Padding(c.Control.Padding)
	ctrl.Critical, ctrl.Noncritical = exts(c.Control.Critical), exts(c.Control.Noncritical)
	cb, err := capsule.EncodeControl(&ctrl, capsule.Format2)
	if err != nil || hex.EncodeToString(cb) != c.ControlCBOR {
		return fmt.Sprintf("CONTROL_CBOR (%v)", err)
	}
	k := accesskey.AccessKey{Type: accesskey.TypeX25519, Material: unhex(c.DKK.Material)}
	copy(k.CredentialID[:], unhex(c.DKK.CredentialID))
	copy(k.CapsuleID[:], unhex(c.DKK.CapsuleID))
	if c.DKK.CapsuleDigest != nil {
		k.Verification = &accesskey.Verification{CapsuleDigest: unhex(*c.DKK.CapsuleDigest)}
	}
	k.Critical, k.Noncritical = exts(c.DKK.Critical), exts(c.DKK.Noncritical)
	kb, err := k.MarshalBody()
	if err != nil || hex.EncodeToString(kb) != c.DKKBody {
		return fmt.Sprintf(".dkk BODY_CBOR (%v)", err)
	}
	return ""
}

// encryptError runs capsule.Encrypt with the options of a case and returns
// its error text, or "ok".
func encryptError(c errorCase) string {
	p := profile.Quicknet()
	if c.ChainHashFlip {
		p.ChainHash[0] ^= 1
	}
	var recipients []age.Recipient
	for _, raw := range c.Recipients {
		s := must(bech32.Encode("age", unhex(raw)))
		recipients = append(recipients, must(age.ParseX25519Recipient(s)))
	}
	opts := capsule.EncryptOptions{
		Profile:            p,
		UnlockAt:           must(time.Parse(time.RFC3339Nano, c.UnlockAt)),
		Policy:             capsule.Policy(c.Policy),
		Recipients:         recipients,
		NewPortableKey:     c.Portable,
		Length:             c.Length,
		Padding:            capsule.Padding(c.Padding),
		Critical:           exts(c.Critical),
		Noncritical:        exts(c.Noncritical),
		ControlCritical:    exts(c.ControlCritical),
		ControlNoncritical: exts(c.ControlNoncritical),
		PublicNote:         c.PublicNote,
		TestVectors:        true,
		Now:                func() time.Time { return must(time.Parse(time.RFC3339Nano, c.Now)) },
	}
	src := bytes.NewReader(make([]byte, min(c.Length, 1)))
	if _, err := capsule.Encrypt(io.Discard, src, opts); err != nil {
		return err.Error()
	}
	return "ok"
}

// noteText runs capsule.EncryptFiles on a file of one byte, for round 1000
// with now at the genesis, with the public note given, and returns its error
// text, or "ok".
func noteText(note string) string {
	genesis := time.Unix(1692803367, 0).UTC()
	opts := capsule.EncryptOptions{
		Profile:    profile.Quicknet(),
		UnlockAt:   genesis.Add(999 * 3 * time.Second),
		Policy:     capsule.TimeOnly,
		PublicNote: note,
		Now:        func() time.Time { return genesis },
	}
	src := []capsule.Source{{Path: "a.txt", Size: 1, Open: func() (io.ReadCloser, error) { return io.NopCloser(strings.NewReader("x")), nil }}}
	if _, err := capsule.EncryptFiles(io.Discard, src, opts); err != nil {
		return err.Error()
	}
	return "ok"
}

func libraries() string {
	info, ok := debug.ReadBuildInfo()
	if !ok {
		return ""
	}
	var parts []string
	for _, d := range info.Deps {
		switch d.Path {
		case "filippo.io/age", "github.com/drand/drand/v2", "github.com/drand/kyber", "github.com/drand/kyber-bls12381", "github.com/drand/tlock":
			parts = append(parts, d.Path+" "+d.Version)
		}
	}
	return strings.Join(parts, ", ")
}