package intent

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	_ "modernc.org/sqlite"

	"github.com/tegwick/fluid-core/internal/contract"
	"github.com/tegwick/fluid-core/internal/evidence"
)

func newStore(t *testing.T) *Store {
	t.Helper()
	ev, err := evidence.OpenSQLite(context.Background(), filepath.Join(t.TempDir(), "e.db"))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = ev.Close() })
	return New(ev, "hall-publishing")
}

const filledIntent = `# Interface Evolution Intent

**Current operational authority mode:**
FLUID-2

## Mission
Publish hall-of-helix entries to a Telegram channel.
`

func TestPutIsIdempotentAndImmutable(t *testing.T) {
	s := newStore(t)
	ctx := context.Background()

	first, err := s.Put(ctx, "IEI-1", filledIntent)
	if err != nil {
		t.Fatal(err)
	}
	if first.Mode != ModeAdvisory {
		t.Errorf("mode = %s, want FLUID-2", first.Mode)
	}

	// Recording the same content again must be a no-op, so startup is safe to
	// repeat.
	again, err := s.Put(ctx, "IEI-1", filledIntent)
	if err != nil {
		t.Fatalf("re-recording identical intent failed: %v", err)
	}
	if again.Digest != first.Digest {
		t.Error("identical documents produced different digests")
	}

	// Changing what a version says, after revisions may already be bound to it,
	// would break the audit question the store exists to answer.
	changed := strings.Replace(filledIntent, "FLUID-2", "FLUID-5", 1)
	if _, err := s.Put(ctx, "IEI-1", changed); !errors.Is(err, ErrImmutable) {
		t.Errorf("mutating a recorded version returned %v, want ErrImmutable", err)
	}
}

func TestParseModeRejectsUnresolvedTemplate(t *testing.T) {
	// The shipped template lists every mode as alternatives. Accepting that and
	// defaulting to something permissive is exactly the wrong failure.
	template, err := os.ReadFile(filepath.Join("..", "..", "spec", "InterfaceEvolutionIntent.md"))
	if err != nil {
		t.Skipf("template not readable: %v", err)
	}
	if _, err := ParseMode(string(template)); err == nil {
		t.Error("the unfilled template was accepted as a governing intent")
	}

	if _, err := ParseMode("no mode declared here"); err == nil {
		t.Error("a document with no authority mode was accepted")
	}
}

func TestAuthorityModeOrdering(t *testing.T) {
	if !ModeExperimental.Allows(ModeAdvisory) {
		t.Error("FLUID-4 should permit advisory authority")
	}
	if ModeAdvisory.Allows(ModeExperimental) {
		t.Error("FLUID-2 must not permit experimental authority")
	}
	if got := ModeBoundedAutonomous.String(); got != "FLUID-5" {
		t.Errorf("String() = %s", got)
	}
}

func TestActiveIntent(t *testing.T) {
	s := newStore(t)
	ctx := context.Background()

	if _, err := s.Active(ctx); !errors.Is(err, ErrNoActive) {
		t.Errorf("Active with nothing recorded returned %v, want ErrNoActive", err)
	}

	if _, err := s.Put(ctx, "IEI-1", filledIntent); err != nil {
		t.Fatal(err)
	}
	if err := s.SetActive(ctx, "IEI-1"); err != nil {
		t.Fatal(err)
	}

	active, err := s.Active(ctx)
	if err != nil {
		t.Fatal(err)
	}
	if active.Version != "IEI-1" {
		t.Errorf("active = %s, want IEI-1", active.Version)
	}

	if err := s.SetActive(ctx, "IEI-missing"); err == nil {
		t.Error("activating an unrecorded version succeeded")
	}
}

func TestBindingIsRecordedAndFirstWins(t *testing.T) {
	s := newStore(t)
	ctx := context.Background()

	if _, err := s.Put(ctx, "IEI-1", filledIntent); err != nil {
		t.Fatal(err)
	}
	v2 := strings.Replace(filledIntent, "FLUID-2", "FLUID-4", 1)
	if _, err := s.Put(ctx, "IEI-2", v2); err != nil {
		t.Fatal(err)
	}

	rev := contract.RevisionID("R-1")
	if err := s.Bind(ctx, rev, "IEI-1"); err != nil {
		t.Fatal(err)
	}

	got, err := s.GoverningIntent(ctx, rev)
	if err != nil {
		t.Fatal(err)
	}
	if got.Version != "IEI-1" {
		t.Errorf("governing intent = %s, want IEI-1", got.Version)
	}

	// A later reassignment is recorded in the audit trail but must not silently
	// become the answer to "what governed this revision".
	if err := s.Bind(ctx, rev, "IEI-2"); err != nil {
		t.Fatal(err)
	}
	got, err = s.GoverningIntent(ctx, rev)
	if err != nil {
		t.Fatal(err)
	}
	if got.Version != "IEI-1" {
		t.Errorf("a later binding overrode the original: got %s", got.Version)
	}
}

func TestUnboundRevisionHasNoIntent(t *testing.T) {
	s := newStore(t)
	if _, err := s.GoverningIntent(context.Background(), "R-unbound"); !errors.Is(err, ErrNotFound) {
		t.Errorf("got %v, want ErrNotFound", err)
	}
}