package stirling.software.SPDF.utils;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import java.util.List;

import org.springframework.web.multipart.MultipartFile;

import com.fathzer.soft.javaluator.DoubleEvaluator;

import io.github.pixee.security.HostValidator;
import io.github.pixee.security.Urls;

public class GeneralUtils {

    public static File convertMultipartFileToFile(MultipartFile multipartFile) throws IOException {
        File tempFile = Files.createTempFile("temp", null).toFile();
        try (FileOutputStream os = new FileOutputStream(tempFile)) {
            os.write(multipartFile.getBytes());
        }
        return tempFile;
    }

    public static void deleteDirectory(Path path) throws IOException {
        Files.walkFileTree(
                path,
                new SimpleFileVisitor<Path>() {
                    @Override
                    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
                            throws IOException {
                        Files.delete(file);
                        return FileVisitResult.CONTINUE;
                    }

                    @Override
                    public FileVisitResult postVisitDirectory(Path dir, IOException exc)
                            throws IOException {
                        Files.delete(dir);
                        return FileVisitResult.CONTINUE;
                    }
                });
    }

    public static String convertToFileName(String name) {
        String safeName = name.replaceAll("[^a-zA-Z0-9]", "_");
        if (safeName.length() > 50) {
            safeName = safeName.substring(0, 50);
        }
        return safeName;
    }

    public static boolean isValidURL(String urlStr) {
        try {
            Urls.create(
                    urlStr, Urls.HTTP_PROTOCOLS, HostValidator.DENY_COMMON_INFRASTRUCTURE_TARGETS);
            return true;
        } catch (MalformedURLException e) {
            return false;
        }
    }

    public static File multipartToFile(MultipartFile multipart) throws IOException {
        Path tempFile = Files.createTempFile("overlay-", ".pdf");
        try (InputStream in = multipart.getInputStream();
                FileOutputStream out = new FileOutputStream(tempFile.toFile())) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
            }
        }
        return tempFile.toFile();
    }

    public static Long convertSizeToBytes(String sizeStr) {
        if (sizeStr == null) {
            return null;
        }

        sizeStr = sizeStr.trim().toUpperCase();
        try {
            if (sizeStr.endsWith("KB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2)) * 1024);
            } else if (sizeStr.endsWith("MB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2))
                                * 1024
                                * 1024);
            } else if (sizeStr.endsWith("GB")) {
                return (long)
                        (Double.parseDouble(sizeStr.substring(0, sizeStr.length() - 2))
                                * 1024
                                * 1024
                                * 1024);
            } else if (sizeStr.endsWith("B")) {
                return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 1));
            } else {
                // Assume MB if no unit is specified
                return (long) (Double.parseDouble(sizeStr) * 1024 * 1024);
            }
        } catch (NumberFormatException e) {
            // The numeric part of the input string cannot be parsed, handle this case
        }

        return null;
    }

    public static List<Integer> parsePageList(String pages, int totalPages, boolean oneBased) {
        if (pages == null) {
            return List.of(1); // Default to first page if input is null
        }
        try {
            return parsePageList(pages.split(","), totalPages, oneBased);
        } catch (NumberFormatException e) {
            return List.of(1); // Default to first page if input is invalid
        }
    }

    public static List<Integer> parsePageList(String[] pages, int totalPages) {
        return parsePageList(pages, totalPages, false);
    }

    public static List<Integer> parsePageList(String[] pages, int totalPages, boolean oneBased) {
        List<Integer> result = new ArrayList<>();
        int offset = oneBased ? 1 : 0;
        for (String page : pages) {
            if ("all".equalsIgnoreCase(page)) {
                for (int i = 0; i < totalPages; i++) {
                    result.add(i + offset);
                }
            } else if (page.contains(",")) {
                // Split the string into parts, could be single pages or ranges
                String[] parts = page.split(",");
                for (String part : parts) {
                    result.addAll(handlePart(part, totalPages, offset));
                }
            } else {
                result.addAll(handlePart(page, totalPages, offset));
            }
        }
        return new ArrayList<>(
                new java.util.LinkedHashSet<>(result)); // Remove duplicates and maintain order
    }

    public static List<Integer> evaluateNFunc(String expression, int maxValue) {
        List<Integer> results = new ArrayList<>();
        DoubleEvaluator evaluator = new DoubleEvaluator();

        // Validate the expression
        if (!expression.matches("[0-9n+\\-*/() ]+")) {
            throw new IllegalArgumentException("Invalid expression");
        }

        int n = 0;
        while (true) {
            // Replace 'n' with the current value of n, correctly handling numbers before 'n'
            String sanitizedExpression = insertMultiplicationBeforeN(expression, n);
            Double result = evaluator.evaluate(sanitizedExpression);

            // Check if the result is null or not within bounds
            if (result == null || result <= 0 || result.intValue() > maxValue) {
                if (n != 0) break;
            } else {
                results.add(result.intValue());
            }
            n++;
        }

        return results;
    }

    private static String insertMultiplicationBeforeN(String expression, int nValue) {
        // Insert multiplication between a number and 'n' (e.g., "4n" becomes "4*n")
        String withMultiplication = expression.replaceAll("(\\d)n", "$1*n");
        // Now replace 'n' with its current value
        return withMultiplication.replaceAll("n", String.valueOf(nValue));
    }

    private static List<Integer> handlePart(String part, int totalPages, int offset) {
        List<Integer> partResult = new ArrayList<>();

        // First check for n-syntax because it should not be processed as a range
        if (part.contains("n")) {
            partResult = evaluateNFunc(part, totalPages);
            // Adjust the results according to the offset
            for (int i = 0; i < partResult.size(); i++) {
                int adjustedValue = partResult.get(i) - 1 + offset;
                partResult.set(i, adjustedValue);
            }
        } else if (part.contains("-")) {
            // Process ranges only if it's not n-syntax
            String[] rangeParts = part.split("-");
            try {
                int start = Integer.parseInt(rangeParts[0]);
                int end = Integer.parseInt(rangeParts[1]);
                for (int i = start; i <= end; i++) {
                    if (i >= 1 && i <= totalPages) {
                        partResult.add(i - 1 + offset);
                    }
                }
            } catch (NumberFormatException e) {
                // Range is invalid, ignore this part
            }
        } else {
            // This is a single page number
            try {
                int pageNum = Integer.parseInt(part.trim());
                if (pageNum >= 1 && pageNum <= totalPages) {
                    partResult.add(pageNum - 1 + offset);
                }
            } catch (NumberFormatException ignored) {
                // Ignore invalid numbers
            }
        }
        return partResult;
    }

    public static boolean createDir(String path) {
        Path folder = Paths.get(path);
        if (!Files.exists(folder)) {
            try {
                Files.createDirectories(folder);
            } catch (IOException e) {
                e.printStackTrace();
                return false;
            }
        }
        return true;
    }
}
