package apt

import (
	"testing"
)

const sampleStanza = `Package: curl
Version: 7.88.1-10+deb12u5
Architecture: amd64
Filename: pool/main/c/curl/curl_7.88.1-10+deb12u5_amd64.deb
SHA256: abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890
Size: 314456`

const sampleStanza2 = `Package: wget
Version: 1.21.3-1+b1
Architecture: amd64
Filename: pool/main/w/wget/wget_1.21.3-1+b1_amd64.deb
SHA256: 0000111122223333444455556666777788889999aaaabbbbccccddddeeeeffff
Size: 512000`

func TestParsePackages_single(t *testing.T) {
	pkgs, err := ParsePackages([]byte(sampleStanza))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if len(pkgs) != 1 {
		t.Fatalf("expected 1 package, got %d", len(pkgs))
	}
	p := pkgs[0]
	if p.Package != "curl" {
		t.Errorf("Package: got %q, want %q", p.Package, "curl")
	}
	if p.Version != "7.88.1-10+deb12u5" {
		t.Errorf("Version: got %q, want %q", p.Version, "7.88.1-10+deb12u5")
	}
	if p.Architecture != "amd64" {
		t.Errorf("Architecture: got %q, want %q", p.Architecture, "amd64")
	}
	if p.Filename != "pool/main/c/curl/curl_7.88.1-10+deb12u5_amd64.deb" {
		t.Errorf("Filename: got %q", p.Filename)
	}
	if p.SHA256 != "abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890" {
		t.Errorf("SHA256: got %q", p.SHA256)
	}
	if p.Size != 314456 {
		t.Errorf("Size: got %d, want %d", p.Size, 314456)
	}
}

func TestParsePackages_multiple(t *testing.T) {
	input := sampleStanza + "\n\n" + sampleStanza2
	pkgs, err := ParsePackages([]byte(input))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if len(pkgs) != 2 {
		t.Fatalf("expected 2 packages, got %d", len(pkgs))
	}
	if pkgs[0].Package != "curl" {
		t.Errorf("first package: got %q, want curl", pkgs[0].Package)
	}
	if pkgs[1].Package != "wget" {
		t.Errorf("second package: got %q, want wget", pkgs[1].Package)
	}
}

func TestParsePackages_empty(t *testing.T) {
	pkgs, err := ParsePackages([]byte(""))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if len(pkgs) != 0 {
		t.Errorf("expected 0 packages, got %d", len(pkgs))
	}
}

func TestParsePackages_missingPackageField(t *testing.T) {
	bad := `Version: 1.0
Architecture: amd64
Filename: pool/main/x/x/x_1.0_amd64.deb
SHA256: 0000000000000000000000000000000000000000000000000000000000000000
Size: 100`
	_, err := ParsePackages([]byte(bad))
	if err == nil {
		t.Error("expected error for missing Package field, got nil")
	}
}

func TestFilterPackages(t *testing.T) {
	pkgs, _ := ParsePackages([]byte(sampleStanza + "\n\n" + sampleStanza2))

	// Only curl is "on disk".
	onDisk := map[string]bool{
		"pool/main/c/curl/curl_7.88.1-10+deb12u5_amd64.deb": true,
	}
	filtered := FilterPackages(pkgs, func(filename string) bool {
		return onDisk[filename]
	})

	if len(filtered) != 1 {
		t.Fatalf("expected 1 filtered package, got %d", len(filtered))
	}
	if filtered[0].Package != "curl" {
		t.Errorf("expected curl, got %q", filtered[0].Package)
	}
}

func TestParseEmitRoundTrip(t *testing.T) {
	input := []byte(sampleStanza + "\n\n" + sampleStanza2 + "\n")
	pkgs, err := ParsePackages(input)
	if err != nil {
		t.Fatalf("parse: %v", err)
	}

	emitted := emitPackages(pkgs)

	reparsed, err := ParsePackages(emitted)
	if err != nil {
		t.Fatalf("reparse: %v", err)
	}
	if len(reparsed) != len(pkgs) {
		t.Fatalf("round-trip length: got %d, want %d", len(reparsed), len(pkgs))
	}
	for i := range pkgs {
		if reparsed[i].Package != pkgs[i].Package {
			t.Errorf("[%d] Package: got %q, want %q", i, reparsed[i].Package, pkgs[i].Package)
		}
		if reparsed[i].Filename != pkgs[i].Filename {
			t.Errorf("[%d] Filename: got %q, want %q", i, reparsed[i].Filename, pkgs[i].Filename)
		}
		if reparsed[i].SHA256 != pkgs[i].SHA256 {
			t.Errorf("[%d] SHA256: got %q, want %q", i, reparsed[i].SHA256, pkgs[i].SHA256)
		}
		if reparsed[i].Size != pkgs[i].Size {
			t.Errorf("[%d] Size: got %d, want %d", i, reparsed[i].Size, pkgs[i].Size)
		}
	}
}