package launch

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"
)

// A bundle that asks to take a worker's work and answers each piece it is handed.
const takingBundle = `#!/bin/sh
while IFS= read -r line; do
  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
  case "$line" in
    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
    *'"method":"tools/list"'*)
      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
      printf '{"jsonrpc":"2.0","id":"s1","method":"mesh/seat.take","params":{"worker":"SEAT_CHANNEL_TELEGRAM_worker"}}\n' ;;
    *'"method":"mesh/work"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{"taken":true}}\n' "$id" ;;
  esac
done
`

type seating struct {
	subscribing
	mu     sync.Mutex
	verb   string
	params string
	handOn func(string, any) (json.RawMessage, error)
}

func (b *seating) Seat(verb string, params json.RawMessage, handOn func(string, any) (json.RawMessage, error)) (json.RawMessage, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	b.verb, b.params, b.handOn = verb, string(params), handOn
	return json.RawMessage(`{}`), nil
}

// novox/hq ADR 0259 §3: a bundle's seat traffic reaches the runtime's bus from its own channel, and the work
// it takes is handed back to it.
func TestABundleTakesASeatsWorkThroughItsOwnChannel(t *testing.T) {
	entry := filepath.Join(t.TempDir(), "bundle")
	if err := os.WriteFile(entry, []byte(takingBundle), 0o755); err != nil {
		t.Fatal(err)
	}
	b := &seating{}
	l, err := Start("telegram", entry, os.Environ(), b, t.Logf)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(l.Stop)
	var handOn func(string, any) (json.RawMessage, error)
	for i := 0; handOn == nil; i++ {
		if i > 100 {
			t.Fatal("the bundle never asked to take its work")
		}
		time.Sleep(20 * time.Millisecond)
		b.mu.Lock()
		handOn = b.handOn
		b.mu.Unlock()
	}
	if b.verb != "take" || b.params != `{"worker":"SEAT_CHANNEL_TELEGRAM_worker"}` {
		t.Fatalf("asked %s %s", b.verb, b.params)
	}
	got, err := handOn("mesh/work", map[string]any{"work": map[string]any{"subject": "mesh.seat.channel.accept.show.telegram"}})
	if err != nil || string(got) != `{"taken":true}` {
		t.Fatalf("the work was not handed to the bundle: %s %v", got, err)
	}
	// Design 47 G §576, §518: a bundle reads the runner's capability words with mesh/capabilities, then runs its put session
	// through the runner's put-chunk, and the sessions of its channel are dropped when the channel closes.
	t.Run("ABundleReadsTheCapabilityWordsRunsAPutSessionAndItsChannelsClosingDropsThem", func(t *testing.T) {
		dir := t.TempDir()
		entry := filepath.Join(dir, "bundle")
		if err := os.WriteFile(entry, []byte(puttingBundle), 0o755); err != nil {
			t.Fatal(err)
		}
		b := &sessionBus{dropped: make(chan struct{})}
		l, err := Start("putter", entry, os.Environ(), b, func(string, ...any) {})
		if err != nil {
			t.Fatal(err)
		}
		t.Cleanup(l.Stop)
		select {
		case <-b.dropped:
		case <-time.After(5 * time.Second):
			t.Fatal("the bundle's sessions were not dropped when its channel closed")
		}
		b.mu.Lock()
		defer b.mu.Unlock()
		if len(b.chunks) != 1 || !strings.HasPrefix(b.chunks[0], "mesh/objects.put-chunk ") || !strings.Contains(b.chunks[0], `"seq":1`) {
			t.Fatalf("the runner took %v", b.chunks)
		}
	})
	// Design 47 G §559: `mesh/publish` with `ack` is answered with its sequence once the bus acknowledged it, or `{error}`;
	// `mesh/subscribe` with `deliver: new` makes a subscription for new messages that ends with the bundle's channel.
	t.Run("APublishWithAckIsAnsweredWithItsSequenceAndASubscriptionForNewMessagesEndsWithTheChannel", func(t *testing.T) {
		dir := t.TempDir()
		entry, out := filepath.Join(dir, "bundle"), filepath.Join(dir, "out")
		if err := os.WriteFile(entry, []byte(findingBundle), 0o755); err != nil {
			t.Fatal(err)
		}
		b := &findingBus{stopped: make(chan struct{})}
		l, err := Start("writer", entry, append(os.Environ(), "FINDING_OUT="+out), b, func(string, ...any) {})
		if err != nil {
			t.Fatal(err)
		}
		t.Cleanup(l.Stop)
		select {
		case <-b.stopped:
		case <-time.After(5 * time.Second):
			t.Fatal("the subscription for new messages was not ended with the bundle's channel")
		}
		got, _ := os.ReadFile(out)
		for _, want := range []string{`"sequence":42`, `"error":"the bus refused it"`} {
			if !strings.Contains(string(got), want) {
				t.Errorf("the bundle was answered %s, want it to hold %s", got, want)
			}
		}
		b.mu.Lock()
		defer b.mu.Unlock()
		if b.pattern != "mesh-conditions.findings-asked" {
			t.Errorf("the subscription was made for %q", b.pattern)
		}
		if len(b.published) != 0 {
			t.Errorf("a publish with ack went the unacknowledged way: %v", b.published)
		}
	})
}

// A bundle that pulls one ask from its worker when it is listed.
const pullingBundle = `#!/bin/sh
while IFS= read -r line; do
  id=$(printf '%s' "$line" | sed -n 's/.*"id":\([0-9]*\)[,}].*/\1/p')
  case "$line" in
    *'"method":"initialize"'*) printf '{"jsonrpc":"2.0","id":%s,"result":{}}\n' "$id" ;;
    *'"method":"tools/list"'*)
      printf '{"jsonrpc":"2.0","id":%s,"result":{"tools":[]}}\n' "$id"
      printf '{"jsonrpc":"2.0","id":"p1","method":"mesh/seat.pull","params":{"worker":"SEAT_NODE_BUILD_GO_DELIVERY_worker","wait_ms":0}}\n' ;;
  esac
done
`

// 1887/A11: a bundle's pull reaches the runtime's bus from its own channel, as its other seat traffic does.
func TestABundlePullsASeatsWorkThroughItsOwnChannel(t *testing.T) {
	entry := filepath.Join(t.TempDir(), "bundle")
	if err := os.WriteFile(entry, []byte(pullingBundle), 0o755); err != nil {
		t.Fatal(err)
	}
	b := &seating{}
	l, err := Start("mesh-build-go", entry, os.Environ(), b, t.Logf)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(l.Stop)
	for i := 0; ; i++ {
		b.mu.Lock()
		verb, params := b.verb, b.params
		b.mu.Unlock()
		if verb == "pull" {
			if params != `{"worker":"SEAT_NODE_BUILD_GO_DELIVERY_worker","wait_ms":0}` {
				t.Fatalf("pulled with %s", params)
			}
			return
		}
		if i > 100 {
			t.Fatal("the bundle's pull never reached the runtime")
		}
		time.Sleep(20 * time.Millisecond)
	}
}