package ledger

import (
	"os"
	"testing"
)

func TestAppendAndRead(t *testing.T) {
	f, err := os.CreateTemp("", "ledger-test-*.jsonl")
	if err != nil {
		t.Fatalf("tempfile: %v", err)
	}
	path := f.Name()
	f.Close()
	defer os.Remove(path)

	l := New(path, "stream-1")
	// ensure empty read
	evs, err := l.ReadAll()
	if err != nil {
		t.Fatalf("read empty: %v", err)
	}
	if len(evs) != 0 {
		t.Fatalf("expected 0 events, got %d", len(evs))
	}

	e1, err := l.Append("route_decision", map[string]any{"tier": "fast"})
	if err != nil {
		t.Fatalf("append1: %v", err)
	}
	if l.LastHash == nil || *l.LastHash != e1.Hash {
		t.Fatalf("lasthash not set after append1")
	}

	e2, err := l.Append("final_output_emitted", map[string]any{"result": "ok"})
	if err != nil {
		t.Fatalf("append2: %v", err)
	}
	if l.LastHash == nil || *l.LastHash != e2.Hash {
		t.Fatalf("lasthash not set after append2")
	}
	if e2.PrevHash == nil || *e2.PrevHash != e1.Hash {
		t.Fatalf("prevhash chain broken")
	}

	evs, err = l.ReadAll()
	if err != nil {
		t.Fatalf("read: %v", err)
	}
	if len(evs) != 2 {
		t.Fatalf("expected 2 events, got %d", len(evs))
	}
	if evs[0].Hash != e1.Hash || evs[1].Hash != e2.Hash {
		t.Fatalf("readback hashes mismatch")
	}
}