package cas

import (
	"os"
	"path/filepath"
	"testing"
)

func TestIsValidHash(t *testing.T) {
	tests := []struct {
		hash string
		want bool
	}{
		{"a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2", true},
		{"0000000000000000000000000000000000000000", true},
		{"ffffffffffffffffffffffffffffffffffffffff", true},
		{"A1B2C3D4E5F6A1B2C3D4E5F6A1B2C3D4E5F6A1B2", false}, // uppercase
		{"g1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2", false}, // non-hex
		{"a1b2c3d4e5f6",                                     false}, // too short
		{"",                                                 false}, // empty
		{"a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3", false}, // too long (41)
	}
	for _, tt := range tests {
		got := isValidHash(tt.hash)
		if got != tt.want {
			t.Errorf("isValidHash(%q) = %v, want %v", tt.hash, got, tt.want)
		}
	}
}

func TestStoreFile(t *testing.T) {
	dir := t.TempDir()
	data := []byte("hello minecraft world")

	hash, err := StoreFile(dir, data)
	if err != nil {
		t.Fatalf("StoreFile failed: %v", err)
	}
	if len(hash) != 40 {
		t.Errorf("expected 40-char hash, got %d", len(hash))
	}

	// File should exist at dir/<prefix>/<hash>.
	path := filepath.Join(dir, hash[:2], hash)
	info, err := os.Stat(path)
	if err != nil {
		t.Fatalf("stored file not found: %v", err)
	}
	if info.Size() != int64(len(data)) {
		t.Errorf("stored file size = %d, want %d", info.Size(), len(data))
	}
}

func TestStoreFile_Duplicate(t *testing.T) {
	dir := t.TempDir()
	data := []byte("same content")

	h1, err := StoreFile(dir, data)
	if err != nil {
		t.Fatalf("first StoreFile failed: %v", err)
	}
	h2, err := StoreFile(dir, data)
	if err != nil {
		t.Fatalf("second StoreFile failed: %v", err)
	}
	if h1 != h2 {
		t.Errorf("same data produced different hashes: %s vs %s", h1, h2)
	}
}

func TestFileExists(t *testing.T) {
	dir := t.TempDir()
	data := []byte("test data")

	hash, _ := StoreFile(dir, data)
	if !FileExists(dir, hash) {
		t.Error("FileExists returned false for stored file")
	}
	if FileExists(dir, "0000000000000000000000000000000000000000") {
		t.Error("FileExists returned true for non-existent file")
	}
}

func TestVerifyAndStore(t *testing.T) {
	dir := t.TempDir()
	data := []byte("verify me")
	hash, _ := StoreFile(dir, data)

	// Correct hash → should succeed (idempotent).
	got, err := VerifyAndStore(dir, data, hash)
	if err != nil {
		t.Errorf("VerifyAndStore with correct hash failed: %v", err)
	}
	if got != hash {
		t.Errorf("hash mismatch: got %s, want %s", got, hash)
	}

	// Wrong hash → should fail.
	_, err = VerifyAndStore(dir, data, "0000000000000000000000000000000000000000")
	if err == nil {
		t.Error("VerifyAndStore with wrong hash should have failed")
	}
}

func TestDetectContentType(t *testing.T) {
	tests := []struct {
		fileName string
		want     string
	}{
		{"mod.jar", "application/java-archive"},
		{"config.json", "application/json"},
		{"skin.png", "image/png"},
		{"pack.zip", "application/zip"},
		{"options.toml", "application/toml"},
		{"server.cfg", "text/plain"},
		{"notes.txt", "text/plain"},
		{"data.xml", "application/xml"},
		{"config.yml", "application/x-yaml"},
		{"config.yaml", "application/x-yaml"},
		{"game.properties", "text/plain"},
		{"unknown.dat", "application/octet-stream"},
		{"noext", "application/octet-stream"},
		{"UPPER.JAR", "application/java-archive"},
	}
	for _, tt := range tests {
		got := detectContentType(tt.fileName)
		if got != tt.want {
			t.Errorf("detectContentType(%q) = %q, want %q", tt.fileName, got, tt.want)
		}
	}
}