package main

import (
	"bytes"
	"crypto/ed25519"
	"crypto/sha256"
	"encoding/hex"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestWriteMirrorPrivateKey(t *testing.T) {
	t.Parallel()

	seed := bytes.Repeat([]byte{0x42}, ed25519.SeedSize)
	out := filepath.Join(t.TempDir(), "mirror.key")
	fingerprint, err := writeMirrorPrivateKey(out, false, bytes.NewReader(seed))

	if err != nil {
		t.Fatalf("write key: %v", err)
	}

	b, err := os.ReadFile(out)

	if err != nil {
		t.Fatalf("read key file: %v", err)
	}

	expectedFile := hex.EncodeToString(seed) + "\n"

	if string(b) != expectedFile {
		t.Fatalf("key file content mismatch: got %q want %q", string(b), expectedFile)
	}

	pub := ed25519.NewKeyFromSeed(seed).Public().(ed25519.PublicKey)
	sum := sha256.Sum256(pub)
	expectedFP := "ed25519:" + hex.EncodeToString(sum[:8])

	if fingerprint != expectedFP {
		t.Fatalf("fingerprint mismatch: got %s want %s", fingerprint, expectedFP)
	}
}

func TestWriteMirrorPrivateKey_NoForceRefusesOverwrite(t *testing.T) {
	t.Parallel()

	out := filepath.Join(t.TempDir(), "mirror.key")

	if err := os.WriteFile(out, []byte("existing\n"), 0o600); err != nil {
		t.Fatalf("seed existing file: %v", err)
	}

	_, err := writeMirrorPrivateKey(out, false, bytes.NewReader(bytes.Repeat([]byte{0x01}, ed25519.SeedSize)))

	if err == nil {
		t.Fatalf("expected overwrite refusal error")
	}

	if !strings.Contains(err.Error(), "already exists") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestWriteMirrorPrivateKey_ForceOverwrites(t *testing.T) {
	t.Parallel()

	out := filepath.Join(t.TempDir(), "mirror.key")

	if err := os.WriteFile(out, []byte("existing\n"), 0o600); err != nil {
		t.Fatalf("seed existing file: %v", err)
	}

	seed := bytes.Repeat([]byte{0x03}, ed25519.SeedSize)

	if _, err := writeMirrorPrivateKey(out, true, bytes.NewReader(seed)); err != nil {
		t.Fatalf("force overwrite key: %v", err)
	}

	b, err := os.ReadFile(out)

	if err != nil {
		t.Fatalf("read overwritten file: %v", err)
	}

	expectedFile := hex.EncodeToString(seed) + "\n"

	if string(b) != expectedFile {
		t.Fatalf("overwritten content mismatch: got %q want %q", string(b), expectedFile)
	}
}