//go:build integration

package web

// The runtime player (novox/hq ADR 0192, ADR 0198; issue 1285): mesh-mail-web is a bundle under runs-as, and
// reaches the bus only through the runtime that launches it, over stdin and stdout (initialize, tools/list,
// tools/call; the bundle's own mesh/ask, mesh/state.<verb>). Nothing in this repository has played that
// protocol's runtime side against a real, built bundle binary before (the survey at this issue's prepare step
// found no precedent), so this harness takes the wire shape from the SDK's own source, never from memory:
// ~/go/pkg/mod/.../mesh-sdk/go@.../stdio.go (the unexported `message`, ServeOn's own switch, c.newID's
// "bundle-<n>" ids, live()'s "before Serve" refusal) and state.go (KeptState.ask's "mesh/state."+verb,
// {"state":...,"key":...} params). The stand-in mail-store answers seat:mail-store.<verb> and records every
// call (AC2); mesh-mail's own account bucket is answered from a real JetStream key-value bucket on a test
// nats-server, named as the controller names a module's state (Module+"_"+StateName, mesh-mail's own
// acceptance_integration_test.go:79-107) — here "mesh-mail_accounts", since mesh-mail-web's own `reads` names
// "mesh-mail.accounts". Compiled by `go vet -tags integration ./...`; never run on this machine (the
// context file's hard rule) — the lead's try runs it for real.

import (
	"bufio"
	"context"
	"encoding/json"
	"fmt"
	"html"
	"io"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/nats-io/nats-server/v2/server"
	"github.com/nats-io/nats.go"
	"github.com/nats-io/nats.go/jetstream"
)

// ---- the wire, copied from the SDK's own stdio.go (its unexported `message`) --------------------------------

// wireMessage mirrors stdio.go's own unexported `message`: newline-framed JSON-RPC, as the runtime and a
// bundle exchange it over stdin/stdout. Copied, not imported (it is unexported there) — this harness plays
// the runtime's own side of exactly that shape.
type wireMessage struct {
	ID     json.RawMessage `json:"id,omitempty"`
	Method string          `json:"method,omitempty"`
	Params json.RawMessage `json:"params,omitempty"`
	Result json.RawMessage `json:"result,omitempty"`
	Error  *wireError      `json:"error,omitempty"`
}

type wireError struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
}

// ---- the stand-in mail-store (issue 1285/AC2, AC4) -------------------------------------------------------

// askRecord is one ask the bundle made, as the harness recorded it (issue 1285/AC2): its key
// ("seat:mail-store.<verb>", stdio.go's own Ask) and its body, whole.
type askRecord struct {
	Key  string
	Body json.RawMessage
}

// mailStoreFunc answers one seat:mail-store.<verb> ask (the key, exactly as stdio.Ask's own caller gives it,
// and its body's arguments already read into a map); known is false when the stand-in was not given an
// answer for that key at all — the player then fails the test naming the ask, rather than only shaping a
// protocol error the bundle's own caller would read as some ordinary failure (issue 1285/AC4).
type mailStoreFunc func(key string, args map[string]any) (result any, err error, known bool)

// standInMailStore is mail-store as the tests in this file and in acceptance_integration_test.go fake it:
// one function per seat verb, called by key, and every call recorded (issue 1285/AC2).
type standInMailStore struct {
	mu sync.Mutex

	Accounts   func(args map[string]any) (any, error)
	Search     func(args map[string]any) (any, error)
	Read       func(args map[string]any) (any, error)
	Send       func(args map[string]any) (any, error)
	SendStatus func(args map[string]any) (any, error)

	calls []askRecord
}

// answer is this stand-in's own mailStoreFunc. The key is matched BEFORE anything is recorded (review
// round 1 finding 1, issue 1430/1523): a key that is not one of mail-store's own five verbs — such as
// seat:mail-reading.<verb>, which handleAsk tries here first and falls through on — is never added to
// Calls/Keys at all, so a test's own "only these verbs were asked" check (acceptance_integration_test.go's
// wantKeys) is never tripped by an ask this stand-in was never for.
func (s *standInMailStore) answer(key string, args map[string]any) (any, error, bool) {
	var f func(args map[string]any) (any, error)
	switch key {
	case "seat:mail-store.accounts":
		f = s.Accounts
	case "seat:mail-store.search":
		f = s.Search
	case "seat:mail-store.read":
		f = s.Read
	case "seat:mail-store.send":
		f = s.Send
	case "seat:mail-store.send-status":
		f = s.SendStatus
	default:
		return nil, nil, false
	}
	raw, _ := json.Marshal(args)
	s.mu.Lock()
	s.calls = append(s.calls, askRecord{Key: key, Body: raw})
	s.mu.Unlock()
	if f == nil {
		return nil, nil, false
	}
	out, err := f(args)
	return out, err, true
}

// Calls is every ask this stand-in has answered so far, a copy (issue 1285/AC2, issue 1268's design test 3).
func (s *standInMailStore) Calls() []askRecord {
	s.mu.Lock()
	defer s.mu.Unlock()
	return append([]askRecord(nil), s.calls...)
}

// Keys is every distinct key asked so far, in the order first seen (design test 3's own "only these verbs").
func (s *standInMailStore) Keys() []string {
	s.mu.Lock()
	defer s.mu.Unlock()
	seen := map[string]bool{}
	var out []string
	for _, c := range s.calls {
		if !seen[c.Key] {
			seen[c.Key] = true
			out = append(out, c.Key)
		}
	}
	return out
}

// ---- the stand-in mail-reading (issue 1523/AC4) ------------------------------------------------------------

// mailReadingFunc is mailStoreFunc's own shape, for seat:mail-reading.<verb> (issue 1523/AC4).
type mailReadingFunc func(key string, args map[string]any) (result any, err error, known bool)

// standInMailReading is mail-reading's own six seat verbs, faked the same shape as standInMailStore above:
// one function per verb, called by key, every call recorded. Extends the harness that issue 1285 built (the
// pattern it already proves): a correction posted on the page reaches this stand-in's Correct, an undo
// reaches Undo, and nothing of mail is read but through mail-store (1523/AC4) — this stand-in never touches
// a mailbox itself.
type standInMailReading struct {
	mu sync.Mutex

	Entries func(args map[string]any) (any, error)
	Groups  func(args map[string]any) (any, error)
	Status  func(args map[string]any) (any, error)
	Correct func(args map[string]any) (any, error)
	Lessons func(args map[string]any) (any, error)
	Undo    func(args map[string]any) (any, error)
	// The list page's verbs (issue 1859): left unset, each answers an error, as the six above do.
	List     func(args map[string]any) (any, error)
	Handle   func(args map[string]any) (any, error)
	Unhandle func(args map[string]any) (any, error)
	Remind   func(args map[string]any) (any, error)
	Record   func(args map[string]any) (any, error)

	calls []askRecord
}

// answer is this stand-in's own mailReadingFunc. A key matched below but left unset by the test answers an
// error, never "unknown" (review round 1 finding 1, issue 1430/1523): accounts.go's mailReadingSection asks
// mail-reading.status on every page load now (issue 1430), so every test from before mail-reading existed
// that loads "/" and never configured this stand-in at all would otherwise fail as an unknown ask; an error
// here is exactly what mailReadingSection itself reads as "mail-reading does not answer" and takes its own
// "unavailable" path, same as the real seat refusing or timing out would. A key that is not one of
// mail-reading's own six verbs is still unknown, as before (never recorded, below).
func (s *standInMailReading) answer(key string, args map[string]any) (any, error, bool) {
	var f func(args map[string]any) (any, error)
	switch key {
	case "seat:mail-reading.entries":
		f = s.Entries
	case "seat:mail-reading.groups":
		f = s.Groups
	case "seat:mail-reading.status":
		f = s.Status
	case "seat:mail-reading.correct":
		f = s.Correct
	case "seat:mail-reading.lessons":
		f = s.Lessons
	case "seat:mail-reading.undo":
		f = s.Undo
	case "seat:mail-reading.list":
		f = s.List
	case "seat:mail-reading.handle":
		f = s.Handle
	case "seat:mail-reading.unhandle":
		f = s.Unhandle
	case "seat:mail-reading.remind":
		f = s.Remind
	case "seat:mail-reading.record":
		f = s.Record
	default:
		return nil, nil, false
	}
	raw, _ := json.Marshal(args)
	s.mu.Lock()
	s.calls = append(s.calls, askRecord{Key: key, Body: raw})
	s.mu.Unlock()
	if f == nil {
		return nil, fmt.Errorf("the test's own stand-in for %s answers nothing", key), true
	}
	out, err := f(args)
	return out, err, true
}

// Calls is every ask this stand-in has answered so far, a copy (1523/AC4).
func (s *standInMailReading) Calls() []askRecord {
	s.mu.Lock()
	defer s.mu.Unlock()
	return append([]askRecord(nil), s.calls...)
}

// ---- the real account bucket, on a real JetStream bus (issue 1285/AC3) ---------------------------------

// AccountsBucketName is the real key-value bucket mesh-mail-web's own account bucket read resolves to: the
// controller's own naming for a module's state, "<module>_<state>" (mesh-mail's
// acceptance_integration_test.go:79-107, Module+"_"+SendsState) — here mesh-mail's own module name and its
// accounts state (issue 1255), matching this module's `reads` entry "mesh-mail.accounts".
const AccountsBucketName = "mesh-mail_accounts"

// newTestBus starts a JetStream-enabled nats-server for the test alone, on a random port with its own temp
// store — copied from mesh-mail's own cmd/mesh-mail/sender_integration_test.go:55-70 (itself copied there
// from modules/mesh-delivery/cmd/mesh-delivery/bus_test.go, the SDK's own testbus being internal).
func newTestBus(t *testing.T) string {
	t.Helper()
	opts := &server.Options{Host: "127.0.0.1", Port: server.RANDOM_PORT, JetStream: true, StoreDir: t.TempDir(),
		NoLog: true, NoSigs: true}
	s, err := server.NewServer(opts)
	if err != nil {
		t.Fatalf("a bus for this test could not be made: %v", err)
	}
	go s.Start()
	if !s.ReadyForConnections(30 * time.Second) {
		s.Shutdown()
		t.Fatal("a bus for this test did not come up within 30s")
	}
	t.Cleanup(func() { s.Shutdown(); s.WaitForShutdown() })
	return s.ClientURL()
}

// newAccountsBucket makes the real key-value bucket mesh-mail's own Mirror would write (issue 1255) on a
// fresh test bus, and puts one key per account given — each value mesh-mail-web's own accountBucketValue
// (accounts.go), itself copied from mesh-mail's AccountValue (modules/mesh-mail/cmd/mesh-mail/mirror.go,
// issue 1255; accounts.go's own comment names the source again). Answers the jetstream.KeyValue the player
// reads mesh-mail.accounts from, and the *nats.Conn/jetstream.JetStream for a test to write more keys with
// (issue 1285/AC3).
func newAccountsBucket(t *testing.T, accounts map[string]accountBucketValue) (jetstream.JetStream, jetstream.KeyValue) {
	t.Helper()
	url := newTestBus(t)
	nc, err := nats.Connect(url)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(nc.Close)
	js, err := jetstream.New(nc)
	if err != nil {
		t.Fatal(err)
	}
	ctx := context.Background()
	kv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: AccountsBucketName})
	if err != nil {
		t.Fatal(err)
	}
	for account, v := range accounts {
		raw, err := json.Marshal(v)
		if err != nil {
			t.Fatal(err)
		}
		if _, err := kv.Put(ctx, account, raw); err != nil {
			t.Fatalf("putting the account bucket's key %q: %v", account, err)
		}
	}
	return js, kv
}

// ---- building the bundle's own binary (issue 1285) ---------------------------------------------------------

// buildMailWebBinary builds mesh-mail-web's own binary into TMPDIR (the brief's own rule: a short TMPDIR,
// issue 1244's long-path lesson), once per test.
func buildMailWebBinary(t *testing.T) string {
	t.Helper()
	dir, err := os.MkdirTemp(os.Getenv("TMPDIR"), "mw-web-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(dir) })
	bin := filepath.Join(dir, "mesh-mail-web")
	cmd := exec.Command("go", "build", "-o", bin, "../../cmd/mesh-mail-web")
	cmd.Dir, err = os.Getwd()
	if err != nil {
		t.Fatal(err)
	}
	cmd.Env = os.Environ()
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("building mesh-mail-web: %v\n%s", err, out)
	}
	return bin
}

// freePort answers a TCP port free at the moment it is asked — released before the bundle (a separate
// process, so this harness cannot hand it a listener directly) is told to bind it. A small, accepted race,
// the same shape as picking any port ahead of starting an external process.
func freePort(t *testing.T) int {
	t.Helper()
	l, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	defer l.Close()
	return l.Addr().(*net.TCPAddr).Port
}

// ---- the runtime player itself (issue 1285) ------------------------------------------------------------

// askFailer is the small part of *testing.T the runtime player reports an unknown ask through (Helper,
// Errorf) — never the whole of it. Every ordinary test gives its own *testing.T (which has both). Issue
// 1285/AC4's own test gives a recorder instead: a failed subtest fails its parent (t.Run answers false, but
// the parent is marked failed regardless, try 2's own finding), which would make "the harness fails the
// test" itself untestable the direct way.
type askFailer interface {
	Helper()
	Errorf(format string, args ...any)
}

// runtimePlayer plays the node's runtime against one started bundle, over its real stdin and stdout:
// initialize, tools/list, tools/call (this harness's own outgoing requests, stdio.go's ServeOn switch), and
// answers to what the bundle itself asks — mesh/ask, mesh/state.<verb> (the bundle's own outgoing requests,
// stdio.go's channel.ask / state.go's KeptState.ask).
type runtimePlayer struct {
	fail askFailer
	cmd  *exec.Cmd
	in   io.WriteCloser

	mu      sync.Mutex
	nextID  int
	waiting map[string]chan wireMessage

	mailStore   mailStoreFunc
	mailReading mailReadingFunc
	js          jetstream.JetStream
}

// startRuntimePlayer starts binary with env, and begins playing the runtime on its stdin/stdout at once: the
// handshake (initialize, notifications/initialized) is done here, so a caller gets back a player already
// past it, exactly as the SDK's own live() expects before any Ask (stdio.go:391-398, live_before_serve_test.go).
// t is used for the process's own setup and cleanup (Fatal, Cleanup) always; failer is where an unknown ask
// is reported (Errorf) — t itself when nil, a recorder for issue 1285/AC4's own test.
func startRuntimePlayer(t *testing.T, binary string, env []string, mailStore mailStoreFunc, mailReading mailReadingFunc, js jetstream.JetStream, failer askFailer) *runtimePlayer {
	t.Helper()
	if failer == nil {
		failer = t
	}
	cmd := exec.Command(binary)
	cmd.Env = env
	stderr := &prefixedLog{t: t, prefix: "mesh-mail-web stderr: "}
	cmd.Stderr = stderr
	stdin, err := cmd.StdinPipe()
	if err != nil {
		t.Fatal(err)
	}
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		t.Fatal(err)
	}
	if err := cmd.Start(); err != nil {
		t.Fatal(err)
	}
	p := &runtimePlayer{fail: failer, cmd: cmd, in: stdin, waiting: map[string]chan wireMessage{}, mailStore: mailStore, mailReading: mailReading, js: js}
	go p.readLoop(stdout)
	t.Cleanup(func() {
		_ = cmd.Process.Kill()
		_ = cmd.Wait()
	})

	if _, err := p.ask("initialize", map[string]any{
		"protocolVersion": "2025-03-26", "capabilities": map[string]any{}, "clientInfo": map[string]any{"name": "test", "version": "1"},
	}); err != nil {
		t.Fatalf("initialize: %v", err)
	}
	if err := p.send(map[string]any{"jsonrpc": "2.0", "method": "notifications/initialized", "params": map[string]any{}}); err != nil {
		t.Fatalf("notifications/initialized: %v", err)
	}
	return p
}

// prefixedLog writes the bundle's own stderr to the test log, a line at a time, so a failure's cause (a
// panic, a refused build, an unreachable issuer) is in the test's own output rather than lost.
type prefixedLog struct {
	t      *testing.T
	prefix string
	buf    []byte
	mu     sync.Mutex
}

func (p *prefixedLog) Write(b []byte) (int, error) {
	p.mu.Lock()
	defer p.mu.Unlock()
	p.buf = append(p.buf, b...)
	for {
		i := strings.IndexByte(string(p.buf), '\n')
		if i < 0 {
			break
		}
		p.t.Log(p.prefix + string(p.buf[:i]))
		p.buf = p.buf[i+1:]
	}
	return len(b), nil
}

// readLoop reads every line the bundle writes to its own stdout: a line with no "method" and an id is an
// answer to something this player asked (stdio.go's own channel read loop tells them apart the same way,
// stdio.go:181-191); a line with a "method" is a request the bundle itself is making, answered by
// handleBundleRequest.
func (p *runtimePlayer) readLoop(stdout io.Reader) {
	scanner := bufio.NewScanner(stdout)
	scanner.Buffer(make([]byte, 1<<20), 1<<24)
	for scanner.Scan() {
		var m wireMessage
		if json.Unmarshal(scanner.Bytes(), &m) != nil {
			continue
		}
		if m.Method == "" && len(m.ID) > 0 {
			var key string
			_ = json.Unmarshal(m.ID, &key)
			p.mu.Lock()
			ch := p.waiting[key]
			delete(p.waiting, key)
			p.mu.Unlock()
			if ch != nil {
				ch <- m
			}
			continue
		}
		if m.Method != "" {
			go p.handleBundleRequest(m)
		}
	}
}

// send writes one JSON-RPC object, newline-framed, to the bundle's stdin — this player's own half of the
// wire (stdio.go's channel.say).
func (p *runtimePlayer) send(m map[string]any) error {
	raw, err := json.Marshal(m)
	if err != nil {
		return err
	}
	p.mu.Lock()
	defer p.mu.Unlock()
	_, err = p.in.Write(append(raw, '\n'))
	return err
}

// ask sends one request to the bundle (initialize, tools/list, tools/call — this player's own outgoing
// calls) and waits for its answer, under an id of this player's own choosing (never "bundle-<n>", which the
// bundle's own outgoing ids use, stdio.go's channel.newID — so the two id spaces never collide on one wire).
func (p *runtimePlayer) ask(method string, params any) (json.RawMessage, error) {
	p.mu.Lock()
	p.nextID++
	id := "player-" + strconv.Itoa(p.nextID)
	ch := make(chan wireMessage, 1)
	p.waiting[id] = ch
	p.mu.Unlock()

	if err := p.send(map[string]any{"jsonrpc": "2.0", "id": id, "method": method, "params": params}); err != nil {
		return nil, err
	}
	select {
	case m := <-ch:
		if m.Error != nil {
			return nil, fmt.Errorf("%s: %s", method, m.Error.Message)
		}
		return m.Result, nil
	case <-time.After(30 * time.Second):
		p.mu.Lock()
		delete(p.waiting, id)
		p.mu.Unlock()
		return nil, fmt.Errorf("%s: no answer within 30s", method)
	}
}

// ToolsList is tools/list, for a test to check what the bundle serves.
func (p *runtimePlayer) ToolsList() ([]string, error) {
	raw, err := p.ask("tools/list", map[string]any{})
	if err != nil {
		return nil, err
	}
	var out struct {
		Tools []struct {
			Name string `json:"name"`
		} `json:"tools"`
	}
	if err := json.Unmarshal(raw, &out); err != nil {
		return nil, err
	}
	names := make([]string, 0, len(out.Tools))
	for _, t := range out.Tools {
		names = append(names, t.Name)
	}
	return names, nil
}

// ToolsCall is tools/call, answering the tool's own text content (stdio.go's own "content":[{"type":"text",
// "text":...}] shape), and whether the runtime itself said isError.
func (p *runtimePlayer) ToolsCall(name string, args map[string]any) (text string, isError bool, err error) {
	raw, askErr := p.ask("tools/call", map[string]any{"name": name, "arguments": args})
	if askErr != nil {
		return "", false, askErr
	}
	var out struct {
		Content []struct {
			Text string `json:"text"`
		} `json:"content"`
		IsError bool `json:"isError"`
	}
	if err := json.Unmarshal(raw, &out); err != nil {
		return "", false, err
	}
	if len(out.Content) == 0 {
		return "", out.IsError, nil
	}
	return out.Content[0].Text, out.IsError, nil
}

// handleBundleRequest answers one request the bundle itself made (mesh/ask, mesh/state.<verb>) — never one
// this player sent (those are answers, read.Loop already told apart and never reach here).
func (p *runtimePlayer) handleBundleRequest(m wireMessage) {
	p.fail.Helper()
	reply := func(result any, errMsg string) {
		out := map[string]any{"jsonrpc": "2.0", "id": json.RawMessage(m.ID)}
		if errMsg != "" {
			out["error"] = map[string]any{"code": -32000, "message": errMsg}
		} else {
			raw, _ := json.Marshal(result)
			out["result"] = json.RawMessage(raw)
		}
		_ = p.send(out)
	}
	switch {
	case m.Method == "mesh/ask":
		p.handleAsk(m, reply)
	case strings.HasPrefix(m.Method, "mesh/state."):
		p.handleState(m, reply)
	default:
		p.fail.Errorf("the bundle asked %s, which the helper does not know (issue 1285/AC4)", m.Method)
		reply(nil, "the helper does not know "+m.Method)
	}
}

// handleAsk is mesh/ask (stdio.go's Ask, params {"key":...,"body":...}): the stand-in mail-store's own
// answer, or — a key the stand-in was given nothing for — the test failing, naming the ask (issue 1285/AC4).
func (p *runtimePlayer) handleAsk(m wireMessage, reply func(result any, errMsg string)) {
	p.fail.Helper()
	var params struct {
		Key  string         `json:"key"`
		Body map[string]any `json:"body"`
	}
	_ = json.Unmarshal(m.Params, &params)
	// 1523/AC4: a key of either stand-in is tried in turn; mail-reading's own verbs never reach mail-store's.
	if p.mailStore != nil {
		if result, err, known := p.mailStore(params.Key, params.Body); known {
			if err != nil {
				reply(nil, err.Error())
				return
			}
			reply(result, "")
			return
		}
	}
	if p.mailReading != nil {
		if result, err, known := p.mailReading(params.Key, params.Body); known {
			if err != nil {
				reply(nil, err.Error())
				return
			}
			reply(result, "")
			return
		}
	}
	p.fail.Errorf("the bundle asked %s, which the helper does not know (issue 1285/AC4)", params.Key)
	reply(nil, "the helper does not know "+params.Key)
}

// handleState is mesh/state.<verb> (state.go's KeptState.ask, params {"state":"<module>.<name>", ...}):
// get and keys answered from the real JetStream bucket this player was given (issue 1285/AC3); any other
// verb, or a `state` this player holds no bucket for, fails the test naming the ask (AC4).
func (p *runtimePlayer) handleState(m wireMessage, reply func(result any, errMsg string)) {
	p.fail.Helper()
	verb := strings.TrimPrefix(m.Method, "mesh/state.")
	var params struct {
		State string `json:"state"`
		Key   string `json:"key"`
	}
	_ = json.Unmarshal(m.Params, &params)
	fail := func() {
		p.fail.Errorf("the bundle asked %s for state %s, which the helper does not know (issue 1285/AC4)", m.Method, params.State)
		reply(nil, "the helper does not know mesh/state."+verb+" for "+params.State)
	}
	// Only mesh-mail.accounts is wired to a real bucket (issue 1285's own scope); any other `state` is
	// unknown to this player.
	if params.State != "mesh-mail.accounts" || p.js == nil {
		fail()
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	kv, err := p.js.KeyValue(ctx, AccountsBucketName)
	if err != nil {
		reply(nil, err.Error())
		return
	}
	switch verb {
	case "get":
		entry, err := kv.Get(ctx, params.Key)
		if err != nil {
			if err == jetstream.ErrKeyNotFound {
				reply(nil, "")
				return
			}
			reply(nil, err.Error())
			return
		}
		reply(map[string]any{"key": params.Key, "value": json.RawMessage(entry.Value()), "revision": entry.Revision()}, "")
	case "keys":
		keys, err := kv.Keys(ctx)
		if err != nil && err != jetstream.ErrNoKeysFound {
			reply(nil, err.Error())
			return
		}
		reply(keys, "")
	default:
		fail()
	}
}

// ---- a started mesh-mail-web, ready for a test (issue 1285, reused by acceptance_integration_test.go) ------

// testClientID is the oidc-client binding's own client id these tests write (issue 1262's oidc.json), and
// the audience the stand-in issuer's own ID tokens are minted for (auth_test.go's fi.idToken) — the two must
// agree, exactly as mesh-mail-web's own real oidc.json and Keycloak's real client would.
const testClientID = "mesh-mail-web-test"

// testNode is MESH_NODE for these tests: InternalHost(testNode) is the Host every request carries, as the
// operator's own setting would assign it on a real machine (ADR 0440 §2).
const testNode = "test-node"

// startedMailWeb is one running mesh-mail-web, built and started by the helper, with its stand-in mail-store,
// its real account bucket, its stand-in identity provider, and an HTTP client that reaches its endpoint —
// everything issue 1285's own tests, and issue 1268's acceptance tests, need.
type startedMailWeb struct {
	player       *runtimePlayer
	store        *standInMailStore
	mailReading  *standInMailReading
	fakeIssuer   *fakeIssuer
	client       *http.Client
	internalHost string
	js           jetstream.JetStream
}

// startMailWeb is startMailWebWithFailer with the test's own *testing.T as the ask failer (every ordinary
// test).
func startMailWeb(t *testing.T, accounts map[string]accountBucketValue, operators []string) *startedMailWeb {
	t.Helper()
	return startMailWebWithFailer(t, accounts, operators, nil)
}

// startMailWebWithFailer builds mesh-mail-web's own binary, starts it with a real account bucket (one key
// per entry in accounts) and the trusted setting operators, and plays the runtime on it until initialize and
// notifications/initialized are done. The stand-in mail-store (startedMailWeb.store) answers nothing until a
// test sets its own fields. failer is where an unknown ask is reported (issue 1285/AC4): nil for the test's
// own *testing.T, or a recorder for a test that must assert on that report without failing itself.
func startMailWebWithFailer(t *testing.T, accounts map[string]accountBucketValue, operators []string, failer askFailer) *startedMailWeb {
	t.Helper()
	binary := buildMailWebBinary(t)
	port := freePort(t)
	internalHost := InternalHost(testNode)

	js, _ := newAccountsBucket(t, accounts)
	fi := newFakeIssuer(t)

	dir := t.TempDir()
	opJSON, err := json.Marshal(map[string]any{"operators": operators})
	if err != nil {
		t.Fatal(err)
	}
	opPath := filepath.Join(dir, "operators.json")
	if err := os.WriteFile(opPath, opJSON, 0o600); err != nil {
		t.Fatal(err)
	}
	oidcJSON, err := json.Marshal(OIDCConfig{ClientID: testClientID, ClientSecret: "s3cr3t", Issuer: fi.Server.URL})
	if err != nil {
		t.Fatal(err)
	}
	oidcPath := filepath.Join(dir, "oidc.json")
	if err := os.WriteFile(oidcPath, oidcJSON, 0o600); err != nil {
		t.Fatal(err)
	}

	store := &standInMailStore{}
	mailReading := &standInMailReading{}
	env := append(os.Environ(),
		"MESH_MAIL_WEB_LISTEN="+strconv.Itoa(port),
		"MESH_NODE="+testNode,
		"MESH_MAIL_WEB_OPERATORS="+opPath,
		"MESH_MAIL_WEB_OIDC="+oidcPath,
		"MESH_SERVED_MODULE=mesh-mail-web",
	)
	player := startRuntimePlayer(t, binary, env, store.answer, mailReading.answer, js, failer)
	waitForHTTP(t, port)

	return &startedMailWeb{
		player: player, store: store, mailReading: mailReading, fakeIssuer: fi,
		client: httpClientForPort(port), internalHost: internalHost, js: js,
	}
}

// httpClientForPort is an http.Client that reaches 127.0.0.1:port for any request, whatever Host the
// request itself carries — so a test sends Host: mail.<node>.internal exactly as the route proxy would,
// never by editing /etc/hosts (the mesh's own hard rule) or needing a real DNS entry. It never follows a
// redirect on its own, so a test reads a 302's own Location (the sign-in redirect, issue 1263).
func httpClientForPort(port int) *http.Client {
	return &http.Client{
		CheckRedirect: func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse },
		Transport: &http.Transport{
			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
				return (&net.Dialer{}).DialContext(ctx, network, fmt.Sprintf("127.0.0.1:%d", port))
			},
		},
	}
}

// waitForHTTP polls 127.0.0.1:port until it accepts a connection: the HTTP endpoint comes up only once
// sign-in's own issuer discovery has succeeded (main.go's serveHTTP retries buildAuth until it does).
func waitForHTTP(t *testing.T, port int) {
	t.Helper()
	deadline := time.Now().Add(30 * time.Second)
	for time.Now().Before(deadline) {
		conn, err := net.DialTimeout("tcp", fmt.Sprintf("127.0.0.1:%d", port), time.Second)
		if err == nil {
			_ = conn.Close()
			return
		}
		time.Sleep(200 * time.Millisecond)
	}
	t.Fatal("mesh-mail-web's HTTP endpoint did not come up within 30s")
}

// followSignInBounce is a plain GET to path carrying no session cookie, followed through RequireSession's own
// one-time bounce (review round 1 finding 1: the first cookieless answer is a 200 page of this origin's own,
// never a redirect — a browser's own meta refresh is what reaches the real one) exactly the way a browser
// would: read the bounce's own refresh target and ask it. Answers that second response: the 302 to the
// issuer, since the cookie is still missing on a request this client never carries one on.
func followSignInBounce(t *testing.T, mw *startedMailWeb, path string) *http.Response {
	t.Helper()
	resp := doWithCookie(t, mw, http.MethodGet, path, nil, nil)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("%s with no session: status %d, want 200 (RequireSession's own one-time bounce, review round 1 finding 1)", path, resp.StatusCode)
	}
	body, err := io.ReadAll(resp.Body)
	_ = resp.Body.Close()
	if err != nil {
		t.Fatal(err)
	}
	return doWithCookie(t, mw, http.MethodGet, extractMetaRefreshURL(t, string(body)), nil, nil)
}

// signIn drives issue 1263's own flow through HTTP alone, as a browser would, never by calling a handler
// directly: it asks path (any page behind RequireSession) with no session, follows RequireSession's own
// one-time bounce (review round 1 finding 1), reads the state the resulting redirect to the stand-in issuer
// carries, and calls back mesh-mail-web's own /signed-in with a fresh ID token the issuer mints for username.
// Answers the session cookie mesh-mail-web set — the callback's own answer is a 200 refresh page too
// (finding 1), but Set-Cookie is read from it exactly the same way a 302's would have been.
func signIn(t *testing.T, mw *startedMailWeb, username, path string) *http.Cookie {
	t.Helper()
	resp := followSignInBounce(t, mw, path)
	if resp.StatusCode != http.StatusFound {
		t.Fatalf("asking %s with no session: status %d, want 302 to sign in", path, resp.StatusCode)
	}
	loc, err := url.Parse(resp.Header.Get("Location"))
	if err != nil {
		t.Fatal(err)
	}
	state := loc.Query().Get("state")
	if state == "" {
		t.Fatalf("the redirect to sign in carries no state: %s", resp.Header.Get("Location"))
	}

	mw.fakeIssuer.nextIDToken = mw.fakeIssuer.idToken(testClientID, username, time.Now(), nil, mw.fakeIssuer.key, mw.fakeIssuer.kid)
	cbReq, err := http.NewRequest(http.MethodGet,
		"http://"+mw.internalHost+SignedInPath+"?state="+url.QueryEscape(state)+"&code=test-code", nil)
	if err != nil {
		t.Fatal(err)
	}
	cbReq.Host = mw.internalHost
	cbResp, err := mw.client.Do(cbReq)
	if err != nil {
		t.Fatal(err)
	}
	defer cbResp.Body.Close()
	for _, c := range cbResp.Cookies() {
		if c.Name == SessionCookie {
			return c
		}
	}
	t.Fatalf("sign-in did not set a session cookie for %q (callback status %d)", username, cbResp.StatusCode)
	return nil
}

// checkCSP is review round 1 finding 3's own strengthening: the content security policy (ADR 0440 §5) is
// Server.ServeHTTP's own first line, set on every answer whatever else happens to it (a page, a 404, a
// sign-in bounce or redirect alike) — so every request these tests drive through doWithCookie and doForm
// checks it, rather than the three hand-picked answers the design test asked of it before.
func checkCSP(t *testing.T, method, path string, resp *http.Response) {
	t.Helper()
	if got := resp.Header.Get("Content-Security-Policy"); got != CSP {
		t.Fatalf("%s %s: Content-Security-Policy %q, want %q", method, path, got, CSP)
	}
}

// doWithCookie is one request to mw's own endpoint, the session cookie attached, Host set to its internal
// name — the shape every page, attachment and send request in these tests shares. Every answer's own CSP is
// checked here (review round 1 finding 3), not left to a handful of tests to ask for themselves.
func doWithCookie(t *testing.T, mw *startedMailWeb, method, path string, body io.Reader, cookie *http.Cookie) *http.Response {
	t.Helper()
	req, err := http.NewRequest(method, "http://"+mw.internalHost+path, body)
	if err != nil {
		t.Fatal(err)
	}
	req.Host = mw.internalHost
	if cookie != nil {
		req.AddCookie(cookie)
	}
	resp, err := mw.client.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	checkCSP(t, method, path, resp)
	return resp
}

// doForm is one form POST to mw's own endpoint, the session cookie attached when given — the shape issue
// 1268's sign-in, CSRF and send scenarios share. Every answer's own CSP is checked here too (finding 3).
func doForm(t *testing.T, mw *startedMailWeb, path string, form url.Values, cookie *http.Cookie) *http.Response {
	t.Helper()
	req, err := http.NewRequest(http.MethodPost, "http://"+mw.internalHost+path, strings.NewReader(form.Encode()))
	if err != nil {
		t.Fatal(err)
	}
	req.Host = mw.internalHost
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	if cookie != nil {
		req.AddCookie(cookie)
	}
	resp, err := mw.client.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	checkCSP(t, http.MethodPost, path, resp)
	return resp
}

// extractMetaRefreshURL reads a page's own meta refresh target out of its rendered HTML (review round 1
// finding 1, finding 3): RequireSession's own bounce, the callback's own return, and the write page's own
// send-status poll (write.go's sendStatusTemplate) all carry one, whatever its own delay. html/template's
// contextual auto-escaping recognises content="...;url=..." inside a meta tag as a URL within an HTML
// attribute, and escapes it as both (an "&" becomes "&amp;"); html.UnescapeString reverses exactly that, so
// this never builds the URL by hand — it reads the one the page itself carries, as a browser's own meta
// refresh would.
func extractMetaRefreshURL(t *testing.T, body string) string {
	t.Helper()
	marker := "; url="
	i := strings.Index(body, marker)
	if i < 0 {
		t.Fatalf("no meta refresh in the page:\n%s", body)
	}
	rest := body[i+len(marker):]
	j := strings.Index(rest, `"`)
	if j < 0 {
		t.Fatalf("the meta refresh's own url is not closed:\n%s", body)
	}
	return html.UnescapeString(rest[:j])
}

// extractHiddenValue reads a hidden input's own value out of a rendered page's HTML, by its field name —
// issue 1284's own form token, which is never answered by any tool, only ever rendered into a page
// (write.go's FormTokenInput).
func extractHiddenValue(body, field string) string {
	marker := `name="` + field + `" value="`
	i := strings.Index(body, marker)
	if i < 0 {
		return ""
	}
	rest := body[i+len(marker):]
	j := strings.Index(rest, `"`)
	if j < 0 {
		return ""
	}
	return rest[:j]
}

// ---- issue 1285's own acceptance criteria -----------------------------------------------------------------

// 1285/AC1: initialize and tools/list complete, and a tools/call of mail-webclient.status answers.
func TestHarnessInitializeToolsListAndStatusCall(t *testing.T) {
	mw := startMailWeb(t, nil, nil)
	mw.store.Accounts = func(map[string]any) (any, error) {
		return map[string]any{"accounts": []any{}}, nil
	}
	names, err := mw.player.ToolsList()
	if err != nil {
		t.Fatalf("tools/list: %v", err)
	}
	if !containsName(names, StatusTool) {
		t.Fatalf("tools/list does not name %s: %v", StatusTool, names)
	}
	text, isError, err := mw.player.ToolsCall(StatusTool, map[string]any{})
	if err != nil {
		t.Fatalf("tools/call %s: %v", StatusTool, err)
	}
	if isError || text == "" {
		t.Fatalf("%s answered isError=%v, text=%q", StatusTool, isError, text)
	}
}

// 1285/AC2: the bundle's ask of seat:mail-store.<verb> is answered by the stand-in, and recorded with its
// arguments.
func TestHarnessRecordsASeatAskWithItsArguments(t *testing.T) {
	mw := startMailWeb(t, nil, nil)
	mw.store.Accounts = func(map[string]any) (any, error) {
		return map[string]any{"accounts": []any{map[string]any{"account": "a"}}}, nil
	}
	if _, _, err := mw.player.ToolsCall(StatusTool, map[string]any{}); err != nil {
		t.Fatal(err)
	}
	calls := mw.store.Calls()
	if len(calls) != 1 || calls[0].Key != "seat:mail-store.accounts" {
		t.Fatalf("calls recorded: %+v", calls)
	}
	var args map[string]any
	if err := json.Unmarshal(calls[0].Body, &args); err != nil {
		t.Fatal(err)
	}
	if len(args) != 0 {
		t.Fatalf("mail-webclient.status's own accounts ask carries arguments: %v", args)
	}
}

// 1285/AC3: a value put in the real key-value bucket for account a is what the bundle's own state read of
// mesh-mail.accounts key a answers — driven through the accounts page (accounts.go), the one production
// path that reads it; there is no tool exposing the bucket read directly.
func TestHarnessStateReadAnswersTheRealBucketsValue(t *testing.T) {
	mw := startMailWeb(t, map[string]accountBucketValue{
		"a": {State: "current", Folders: []accountBucketFolder{{Name: "INBOX", Mails: 7, Unread: 3}}},
	}, []string{"alice"})
	mw.store.Accounts = func(map[string]any) (any, error) {
		return map[string]any{"accounts": []any{map[string]any{"account": "a", "kind": "imap", "address": "a@example.org", "state": "current"}}}, nil
	}
	cookie := signIn(t, mw, "alice", "/")
	resp := doWithCookie(t, mw, http.MethodGet, "/all", nil, cookie)
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status %d: %s", resp.StatusCode, body)
	}
	text := string(body)
	for _, want := range []string{"INBOX", "7 mail(s)", "3 unread"} {
		if !strings.Contains(text, want) {
			t.Fatalf("the page does not show the real bucket's value (%q missing):\n%s", want, text)
		}
	}
}

// askFailRecorder is a fake askFailer: it keeps every message instead of failing a test (try 2's own
// finding — a failed subtest fails its parent through t.Run, which would make "the harness fails the test"
// itself untestable the direct way), so issue 1285/AC4's own test can assert on what was reported without
// failing itself.
type askFailRecorder struct {
	mu       sync.Mutex
	messages []string
}

func (r *askFailRecorder) Helper() {}

func (r *askFailRecorder) Errorf(format string, args ...any) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.messages = append(r.messages, fmt.Sprintf(format, args...))
}

func (r *askFailRecorder) Messages() []string {
	r.mu.Lock()
	defer r.mu.Unlock()
	return append([]string(nil), r.messages...)
}

// 1285/AC4: the bundle asking something the helper does not know is reported through the ask failer, naming
// the ask, and the bundle's own ask gets an error answer back.
func TestHarnessFailsTheTestWhenTheBundleAsksSomethingUnknown(t *testing.T) {
	recorder := &askFailRecorder{}
	mw := startMailWebWithFailer(t, nil, nil, recorder)
	// mw.store.Accounts is left nil on purpose: mail-webclient.status's own ask of seat:mail-store.accounts
	// is then unknown to the stand-in.
	text, isError, err := mw.player.ToolsCall(StatusTool, map[string]any{})
	if err != nil {
		t.Fatalf("tools/call: %v", err)
	}
	if isError {
		t.Fatalf("mail-webclient.status answered isError; it catches the ask's own error itself: %s", text)
	}
	if !strings.Contains(text, "does not answer") {
		t.Fatalf("mail-webclient.status's own text does not show the ask got an error answer: %s", text)
	}
	messages := recorder.Messages()
	if len(messages) != 1 || !strings.Contains(messages[0], "seat:mail-store.accounts") {
		t.Fatalf("the recorder's messages: %v, want exactly one naming seat:mail-store.accounts", messages)
	}
}