package ingest

import (
	"bytes"
	"context"
	"errors"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"testing"
	"time"

	"textmachine/platform/internal/money"
)

// fakeEngine writes a shell script that behaves like tmctl's contract: NDJSON on stdout, human log
// on stderr, and one of the ratified exit codes. The supervision path is exercised with a real
// process — a mocked one would prove nothing about pipes, signals or exit codes.
func fakeEngine(t *testing.T, stdout, stderr string, code int) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "tmctl")
	script := "#!/bin/sh\nprintf '%s' " + shellQuote(stdout) + "\nprintf '%s' " + shellQuote(stderr) + " >&2\nexit " + strconv.Itoa(code) + "\n"
	if err := os.WriteFile(path, []byte(script), 0o755); err != nil {
		t.Fatal(err)
	}
	return path
}

func TestRunIngestsStreamAndMapsExitCode(t *testing.T) {
	stream := helloLine + "\n" + `{"seq":2,"type":"bank_stop","data":{"terms_proposed":7}}` + "\n"
	var engineLog bytes.Buffer
	s := &Supervisor{
		Bin:       fakeEngine(t, stream, "bank-mining: new terms await owner signature\n", 3),
		Workdir:   t.TempDir(),
		EngineLog: &engineLog,
	}
	sink := &recordingSink{}

	got, err := s.Run(context.Background(), sink, "translate", "--verify-bank")
	if err != nil {
		t.Fatalf("run: %v", err)
	}
	if got != OutcomeBankStop {
		t.Fatalf("outcome = %q, want %q (exit 3 is a deliberate halt, not a failure)", got, OutcomeBankStop)
	}
	if len(sink.applied) != 1 || sink.applied[0].Type != TypeBankStop {
		t.Fatalf("stream not materialized: %+v", sink.applied)
	}
	// The engine's own log must land in the file, not in our structured logger: it carries money.
	if !bytes.Contains(engineLog.Bytes(), []byte("bank-mining")) {
		t.Fatalf("engine stderr not captured: %q", engineLog.String())
	}
}

func TestRunReportsOutcomeEvenWhenStreamBreaks(t *testing.T) {
	s := &Supervisor{Bin: fakeEngine(t, "not a stream\n", "", 1), Workdir: t.TempDir()}
	got, err := s.Run(context.Background(), &recordingSink{})
	if err == nil {
		t.Fatal("a broken stream must be reported")
	}
	if got != OutcomeFailed {
		t.Fatalf("outcome = %q, want %q", got, OutcomeFailed)
	}
}

// PD-12. When the sink stops accepting, the run must END, not continue unwatched: a translation
// keeps spending for hours, and its ceiling and bank-stop events would go to io.Discard with nobody
// told. Mutation caught: dropping the stop() after a failed Ingest — the test then waits out the
// child's sleep and times out.
func TestFailingSinkStopsTheRun(t *testing.T) {
	stream := helloLine + "\n" + `{"seq":2,"type":"progress","data":{}}` + "\n"
	path := filepath.Join(t.TempDir(), "tmctl")
	// Emits a valid stream, then behaves like a long translation: it stays alive until told to go.
	script := "#!/bin/sh\nprintf '%s' " + shellQuote(stream) + "\nsleep 60\nexit 0\n"
	if err := os.WriteFile(path, []byte(script), 0o755); err != nil {
		t.Fatal(err)
	}
	s := &Supervisor{Bin: path, Workdir: t.TempDir()}

	done := make(chan struct{})
	go func() {
		defer close(done)
		if _, err := s.Run(context.Background(), &failingSink{}, "translate"); err == nil {
			t.Error("a failing sink must be reported")
		}
	}()
	select {
	case <-done:
	case <-time.After(20 * time.Second):
		t.Fatal("the run outlived its sink: the engine was left running while the platform was blind")
	}
}

type failingSink struct{}

func (failingSink) Begin(context.Context, Hello) error { return nil }

func (failingSink) Apply(context.Context, Envelope, Cursor) error {
	return errors.New("database is down")
}

func TestStatusDecodesTheResyncChannel(t *testing.T) {
	// A real `tmctl status --json` body carries money and snapshot fields; the allowlist ignores
	// them, and this fixture keeps one of each to prove it.
	body := `{"book_id":"gzr","snapshot_id":"a1","committed_usd":1.25,"reserved_usd":0.5,
		"total_units":10,"done":4,"pending":6,"eta_seconds":900,"unsigned_bank_terms":3,
		"chapters":[{"chapter":1,"units_total":2,"units_done":2,"cost_usd":0.4,"verdict":"pass"}]}`
	s := &Supervisor{Bin: fakeEngine(t, body, "", 0), Workdir: t.TempDir()}
	got, err := s.Status(context.Background())
	if err != nil {
		t.Fatalf("status: %v", err)
	}
	if got.BookID != "gzr" || got.Done != 4 || got.ETASeconds != 900 || got.UnsignedBankTerms != 3 {
		t.Fatalf("status = %+v", got)
	}
	if got.Spend == nil || *got.Spend != 1_250_000 {
		t.Fatalf("spend must be metered from status: %v", got.Spend)
	}
	// A status without the figure is not a status reporting zero.
	absent, err := DecodeStatus([]byte(`{"book_id":"gzr"}`))
	if err != nil {
		t.Fatal(err)
	}
	if absent.Spend != nil {
		t.Fatalf("a missing committed_usd read as %v", *absent.Spend)
	}
	if len(got.Chapters) != 1 || got.Chapters[0].UnitsDone != 2 {
		t.Fatalf("chapters = %+v", got.Chapters)
	}
}

// The dev path reads the same shell contract as the production one: `status --json` over a book with
// a flagged unit prints the report and exits 2, and a stand whose demo book flags one unit must not
// lose its reconciliation channel over that (acceptance dofix ФП-1).
func TestTheDevelopmentStatusReadsAFlaggedBookToo(t *testing.T) {
	s := &Supervisor{
		Bin:     fakeEngine(t, `{"book_id":"gzr","flagged":1,"committed_usd":2}`, "tmctl: 1 unit flagged\n", 2),
		Workdir: t.TempDir(),
	}
	got, err := s.Status(context.Background())
	if err != nil {
		t.Fatalf("a flagged book could not be read: %v", err)
	}
	if got.Flagged != 1 || got.Spend == nil || *got.Spend != 2*money.PerUSD {
		t.Fatalf("status = %+v", got)
	}
	// And the other half of the rule: the code alone is not the answer.
	s = &Supervisor{Bin: fakeEngine(t, "=== STATUS: gzr ===", "", 2), Workdir: t.TempDir()}
	if _, err := s.Status(context.Background()); err == nil {
		t.Fatal("a human dashboard was accepted as a report because the code was 2")
	}
}

func shellQuote(s string) string { return "'" + strings.ReplaceAll(s, "'", `'\''`) + "'" }

// A run we stopped ourselves is not a failed run. exec reports a cancelled command as
// context.Canceled instead of an *ExitError, so reading the outcome off the wait error alone marks
// every gracefully stopped translation as failed — every one in flight on an ordinary SIGTERM.
// Mutation caught: going back to `errors.As(waitErr, &exitErr)` as the only source of the outcome.
func TestStoppedRunKeepsTheEnginesOutcome(t *testing.T) {
	path := filepath.Join(t.TempDir(), "tmctl")
	// Behaves like tmctl: stops on the interrupt and exits 0.
	script := "#!/bin/sh\ntrap 'exit 0' INT\nprintf '%s' " + shellQuote(helloLine+"\n") + "\nsleep 30\n"
	if err := os.WriteFile(path, []byte(script), 0o755); err != nil {
		t.Fatal(err)
	}
	s := &Supervisor{Bin: path, Workdir: t.TempDir()}

	ctx, cancel := context.WithCancel(context.Background())
	type result struct {
		outcome Outcome
		err     error
	}
	done := make(chan result, 1)
	go func() {
		o, err := s.Run(ctx, nopSink{}, "translate")
		done <- result{o, err}
	}()
	time.Sleep(200 * time.Millisecond) // let the engine reach its sleep
	cancel()

	select {
	case got := <-done:
		if got.outcome == OutcomeFailed {
			t.Fatalf("a run stopped by us reported %q; the engine exited 0", got.outcome)
		}
		if !errors.Is(got.err, context.Canceled) {
			t.Fatalf("a stopped run must be distinguishable from a finished one, got err %v", got.err)
		}
	case <-time.After(20 * time.Second):
		t.Fatal("Run did not return")
	}
}

// nopSink accepts everything and records nothing: this test is about the run's OUTCOME, not about
// what the sink saw.
type nopSink struct{}

func (nopSink) Begin(context.Context, Hello) error { return nil }

func (nopSink) Apply(context.Context, Envelope, Cursor) error { return nil }