using Astralis;
using Invercargill;
using Invercargill.DataStructures;

namespace Spry.Tools {

    public class Mkssr : Object {

        private static bool show_version = false;
        private static string? output_file = null;
        private static string? content_type_override = null;
        private static string? resource_name_override = null;
        private static bool generate_vala = false;
        private static string? namespace_name = null;

        private const OptionEntry[] options = {
            { "output", 'o', 0, OptionArg.FILENAME, ref output_file, "Output file name (default: input.ssr or ClassNameResource.vala)", "FILE" },
            { "content-type", 'c', 0, OptionArg.STRING, ref content_type_override, "Override content type (e.g., text/html)", "TYPE" },
            { "name", 'n', 0, OptionArg.STRING, ref resource_name_override, "Override resource name (default: input filename)", "NAME" },
            { "vala", '\0', 0, OptionArg.NONE, ref generate_vala, "Generate Vala source file instead of SSR", null },
            { "ns", '\0', 0, OptionArg.STRING, ref namespace_name, "Namespace for generated Vala class (requires --vala)", "NAMESPACE" },
            { "version", 'v', 0, OptionArg.NONE, ref show_version, "Show version information", null },
            { null }
        };

        public static int main(string[] args) {
            try {
                var opt_context = new OptionContext("INPUT_FILE - Generate a Spry Static Resource file");
                opt_context.set_help_enabled(true);
                opt_context.add_main_entries(options, null);
                opt_context.parse(ref args);
            } catch (OptionError e) {
                stderr.printf("Error: %s\n", e.message);
                stderr.printf("Run '%s --help' for more information.\n", args[0]);
                return 1;
            }

            if (show_version) {
                stdout.printf("spry-mkssr 0.1\n");
                return 0;
            }

            // Validate --ns requires --vala
            if (namespace_name != null && !generate_vala) {
                stderr.printf("Error: --ns requires --vala flag.\n");
                return 1;
            }

            // Get input file from remaining arguments
            string? input_file = null;
            if (args.length > 1) {
                input_file = args[1];
            }

            if (input_file == null) {
                stderr.printf("Error: No input file specified.\n");
                stderr.printf("Run '%s --help' for more information.\n", args[0]);
                return 1;
            }

            // Determine output file and class name base
            string actual_output;
            string? class_name_base = null;
            if (output_file != null) {
                actual_output = output_file;
            } else if (generate_vala) {
                // Generate Vala filename from resource name (if -n specified) or input file
                class_name_base = resource_name_override ?? Path.get_basename(input_file);
                actual_output = make_pascal_case(class_name_base) + "Resource.vala";
            } else {
                actual_output = input_file + ".ssr";
            }

            try {
                var tool = new Mkssr();
                if (generate_vala) {
                    tool.generate_vala_source(input_file, actual_output, content_type_override, resource_name_override, namespace_name, class_name_base);
                } else {
                    tool.generate_ssr(input_file, actual_output, content_type_override, resource_name_override);
                }
                stdout.printf("Generated: %s\n", actual_output);
                return 0;
            } catch (Error e) {
                stderr.printf("Error: %s\n", e.message);
                return 1;
            }
        }

        public void generate_ssr(string input_path, string output_path, string? content_type_override, string? resource_name_override) throws Error {
            // Read input file
            var input_file = File.new_for_path(input_path);
            if (!input_file.query_exists()) {
                throw new IOError.NOT_FOUND(@"Input file '$input_path' does not exist");
            }

            var file_info = input_file.query_info("standard::size", 0);
            var file_size = (size_t)file_info.get_size();
            
            var input_stream = new DataInputStream(input_file.read());
            var input_bytes = input_stream.read_bytes(file_size);
            input_stream.close();

            // Get the data as uint8[] (copy to ensure we own it)
            var input_data = new uint8[input_bytes.get_size()];
            Memory.copy(input_data, input_bytes.get_data(), input_bytes.get_size());

            // Get file name and content type
            var name = resource_name_override ?? Path.get_basename(input_path);
            string content_type;
            if (content_type_override != null) {
                content_type = content_type_override;
            } else {
                content_type = guess_content_type(name, input_data);
            }

            // Compute hash for ETag (SHA-512 = 64 bytes)
            var hash = compute_hash(input_data);

            // Compress with all encodings at highest compression using Astralis compressors
            var encodings = new List<EncodedData>();

            // Identity (no compression) - always included
            var identity_data = new uint8[input_data.length];
            Memory.copy(identity_data, input_data, input_data.length);
            encodings.append(new EncodedData("identity", (owned)identity_data));

            // Create ByteBuffer from input data for compression
            var input_buffer = new ByteBuffer.from_byte_array((owned)input_data);

            // GZip at highest compression
            stdout.printf("Compressing with gzip...\n");
            var gzip_compressor = new GzipCompressor(9);
            var gzip_compressed = gzip_compressor.compress_buffer(input_buffer, null);
            var gzip_data = gzip_compressed.to_array();
            stdout.printf("  gzip: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, gzip_compressed.length, 
                100.0 * gzip_compressed.length / file_size);
            // Only add if smaller than original
            if (gzip_compressed.length < file_size) {
                encodings.append(new EncodedData("gzip", (owned)gzip_data));
            } else {
                stdout.printf("  Skipping gzip (not smaller than original)\n");
            }

            // Zstandard at highest compression
            stdout.printf("Compressing with zstd...\n");
            var zstd_compressor = new ZstdCompressor(19);
            var zstd_compressed = zstd_compressor.compress_buffer(input_buffer, null);
            var zstd_data = zstd_compressed.to_array();
            stdout.printf("  zstd: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, zstd_compressed.length, 
                100.0 * zstd_compressed.length / file_size);
            // Only add if smaller than original
            if (zstd_compressed.length < file_size) {
                encodings.append(new EncodedData("zstd", (owned)zstd_data));
            } else {
                stdout.printf("  Skipping zstd (not smaller than original)\n");
            }

            // Brotli at highest compression
            stdout.printf("Compressing with brotli...\n");
            var brotli_compressor = new BrotliCompressor(11);
            var brotli_compressed = brotli_compressor.compress_buffer(input_buffer, null);
            var brotli_data = brotli_compressed.to_array();
            stdout.printf("  brotli: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, brotli_compressed.length, 
                100.0 * brotli_compressed.length / file_size);
            // Only add if smaller than original
            if (brotli_compressed.length < file_size) {
                encodings.append(new EncodedData("br", (owned)brotli_data));
            } else {
                stdout.printf("  Skipping brotli (not smaller than original)\n");
            }

            // Write output file
            write_ssr_file(output_path, name, content_type, hash, encodings);
        }

        public void generate_vala_source(string input_path, string output_path, string? content_type_override, string? resource_name_override, string? namespace_name, string? class_name_base) throws Error {
            // Read input file
            var input_file = File.new_for_path(input_path);
            if (!input_file.query_exists()) {
                throw new IOError.NOT_FOUND(@"Input file '$input_path' does not exist");
            }

            var file_info = input_file.query_info("standard::size", 0);
            var file_size = (size_t)file_info.get_size();
            
            var input_stream = new DataInputStream(input_file.read());
            var input_bytes = input_stream.read_bytes(file_size);
            input_stream.close();

            // Get the data as uint8[] (copy to ensure we own it)
            var input_data = new uint8[input_bytes.get_size()];
            Memory.copy(input_data, input_bytes.get_data(), input_bytes.get_size());

            // Get file name and content type
            var name = resource_name_override ?? Path.get_basename(input_path);
            string content_type;
            if (content_type_override != null) {
                content_type = content_type_override;
            } else {
                content_type = guess_content_type(name, input_data);
            }

            // Compute hash for ETag (SHA-512 hex string)
            var hash_hex = compute_hash_hex(input_data);

            // Determine class name: use class_name_base if provided (from -n flag), otherwise from output path
            string class_name;
            if (class_name_base != null) {
                class_name = make_pascal_case(class_name_base) + "Resource";
            } else {
                class_name = Path.get_basename(output_path);
                if (class_name.has_suffix(".vala")) {
                    class_name = class_name.substring(0, class_name.length - 5);
                }
            }

            // Compress with all encodings at highest compression using Astralis compressors
            var encodings = new List<EncodedData>();

            // Identity (no compression) - always included
            var identity_data = new uint8[input_data.length];
            Memory.copy(identity_data, input_data, input_data.length);
            encodings.append(new EncodedData("identity", (owned)identity_data));

            // Create ByteBuffer from input data for compression
            var input_buffer = new ByteBuffer.from_byte_array((owned)input_data);

            // GZip at highest compression
            stdout.printf("Compressing with gzip...\n");
            var gzip_compressor = new GzipCompressor(9);
            var gzip_compressed = gzip_compressor.compress_buffer(input_buffer, null);
            var gzip_data = gzip_compressed.to_array();
            stdout.printf("  gzip: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, gzip_compressed.length, 
                100.0 * gzip_compressed.length / file_size);
            // Only add if smaller than original
            if (gzip_compressed.length < file_size) {
                encodings.append(new EncodedData("gzip", (owned)gzip_data));
            } else {
                stdout.printf("  Skipping gzip (not smaller than original)\n");
            }

            // Zstandard at highest compression
            stdout.printf("Compressing with zstd...\n");
            var zstd_compressor = new ZstdCompressor(19);
            var zstd_compressed = zstd_compressor.compress_buffer(input_buffer, null);
            var zstd_data = zstd_compressed.to_array();
            stdout.printf("  zstd: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, zstd_compressed.length, 
                100.0 * zstd_compressed.length / file_size);
            // Only add if smaller than original
            if (zstd_compressed.length < file_size) {
                encodings.append(new EncodedData("zstd", (owned)zstd_data));
            } else {
                stdout.printf("  Skipping zstd (not smaller than original)\n");
            }

            // Brotli at highest compression
            stdout.printf("Compressing with brotli...\n");
            var brotli_compressor = new BrotliCompressor(11);
            var brotli_compressed = brotli_compressor.compress_buffer(input_buffer, null);
            var brotli_data = brotli_compressed.to_array();
            stdout.printf("  brotli: %zu -> %zu bytes (%.1f%%)\n", 
                file_size, brotli_compressed.length, 
                100.0 * brotli_compressed.length / file_size);
            // Only add if smaller than original
            if (brotli_compressed.length < file_size) {
                encodings.append(new EncodedData("br", (owned)brotli_data));
            } else {
                stdout.printf("  Skipping brotli (not smaller than original)\n");
            }

            // Write Vala source file
            write_vala_file(output_path, class_name, name, content_type, hash_hex, encodings, namespace_name);
        }

        private string guess_content_type(string filename, uint8[] sample_data) {
            bool result_uncertain;
            var content_type = ContentType.guess(filename, sample_data, out result_uncertain);
            var mime = ContentType.get_mime_type(content_type);
            
            return mime ?? "application/octet-stream";
        }

        private uint8[] compute_hash(uint8[] data) {
            // Use SHA-512 for the hash (64 bytes)
            var checksum = new Checksum(ChecksumType.SHA512);
            checksum.update(data, data.length);
            
            // Get raw bytes of the hash
            var hex_string = checksum.get_string();
            var hash_bytes = new uint8[64];
            for (var i = 0; i < 64; i++) {
                var hex_byte = hex_string.substring(i * 2, 2);
                // Parse hex byte manually
                int val = 0;
                for (int j = 0; j < 2; j++) {
                    val *= 16;
                    var c = hex_byte.get(j);
                    if (c >= '0' && c <= '9') {
                        val += c - '0';
                    } else if (c >= 'a' && c <= 'f') {
                        val += c - 'a' + 10;
                    } else if (c >= 'A' && c <= 'F') {
                        val += c - 'A' + 10;
                    }
                }
                hash_bytes[i] = (uint8)val;
            }
            return hash_bytes;
        }

        private string compute_hash_hex(uint8[] data) {
            var checksum = new Checksum(ChecksumType.SHA512);
            checksum.update(data, data.length);
            return checksum.get_string();
        }

        private void write_ssr_file(string path, string name, string content_type, uint8[] hash, List<EncodedData> encodings) throws Error {
            var output_file = File.new_for_path(path);
            var output_stream = new DataOutputStream(output_file.replace(null, false, FileCreateFlags.NONE));

            // Write magic number: "spry-sr\0"
            output_stream.put_byte('s');
            output_stream.put_byte('p');
            output_stream.put_byte('r');
            output_stream.put_byte('y');
            output_stream.put_byte('-');
            output_stream.put_byte('s');
            output_stream.put_byte('r');
            output_stream.put_byte(0);

            // Write name field
            write_string_field(output_stream, name);

            // Write content type field
            write_string_field(output_stream, content_type);

            // Write hash (64 bytes)
            output_stream.write(hash);

            // Calculate header size to determine starting offset
            var header_size = 8; // magic
            header_size += 1 + name.data.length; // name field
            header_size += 1 + content_type.data.length; // content type field
            header_size += 64; // hash
            header_size += 1; // encoding count byte
            
            // Add size of each encoding header
            foreach (var encoding in encodings) {
                header_size += 1 + encoding.type.data.length; // type string field
                header_size += 8; // offset
                header_size += 8; // size
            }

            // Write encoding count
            output_stream.put_byte((uint8)encodings.length());

            // Write encoding headers with offsets
            uint64 current_offset = header_size;
            foreach (var encoding in encodings) {
                write_string_field(output_stream, encoding.type);
                output_stream.put_uint64(current_offset);
                output_stream.put_uint64(encoding.data.length);
                current_offset += encoding.data.length;
            }

            // Write encoding data
            foreach (var encoding in encodings) {
                output_stream.write(encoding.data);
            }

            output_stream.close();
        }

        private void write_vala_file(string path, string class_name, string name, string content_type, string hash_hex, List<EncodedData> encodings, string? namespace_name) throws Error {
            var output_file = File.new_for_path(path);
            var output_stream = new DataOutputStream(output_file.replace(null, false, FileCreateFlags.NONE));

            // Determine indentation based on namespace
            string indent = namespace_name != null ? "    " : "";
            string indent2 = namespace_name != null ? "        " : "    ";
            string indent3 = namespace_name != null ? "            " : "        ";
            string indent4 = namespace_name != null ? "                " : "            ";

            // Write using statements
            output_stream.put_string("using Spry;\n");
            output_stream.put_string("using Invercargill;\n\n");

            // Write namespace if provided
            if (namespace_name != null) {
                output_stream.put_string(@"namespace $(namespace_name) {\n\n");
            }

            // Write comment and class declaration
            output_stream.put_string(@"$(indent)// Generated by spry-mkssr\n");
            output_stream.put_string(@"$(indent)public class $(class_name) : ConstantStaticResource {\n\n");

            // Write properties
            output_stream.put_string(@"$(indent2)public override string name { get { return \"$name\"; } }\n");
            output_stream.put_string(@"$(indent2)public override string file_hash { get { return \"$hash_hex\"; } }\n");
            output_stream.put_string(@"$(indent2)public override string content_type { get { return \"$content_type\"; } }\n\n");

            // Write get_best_encoding method
            output_stream.put_string(@"$(indent2)public override string get_best_encoding(Set<string> supported) {\n");
            
            // Sort encodings by size (smallest first) - build a sorted array
            var sorted_encodings = new EncodedData[encodings.length()];
            int idx = 0;
            foreach (var enc in encodings) {
                sorted_encodings[idx++] = enc;
            }
            // Simple bubble sort by size
            for (int i = 0; i < sorted_encodings.length - 1; i++) {
                for (int j = i + 1; j < sorted_encodings.length; j++) {
                    if (sorted_encodings[i].data.length > sorted_encodings[j].data.length) {
                        var tmp = sorted_encodings[i];
                        sorted_encodings[i] = sorted_encodings[j];
                        sorted_encodings[j] = tmp;
                    }
                }
            }

            // Check in order of smallest to largest
            foreach (var encoding in sorted_encodings) {
                if (encoding.type == "identity") continue; // Handle identity last
                output_stream.put_string(@"$(indent3)if (supported.has(\"$(encoding.type)\")) return \"$(encoding.type)\";\n");
            }
            output_stream.put_string(@"$(indent3)return \"identity\";\n");
            output_stream.put_string(@"$(indent2)}\n\n");

            // Write get_encoding method
            output_stream.put_string(@"$(indent2)public override unowned uint8[] get_encoding(string encoding) {\n");
            output_stream.put_string(@"$(indent3)switch (encoding) {\n");
            foreach (var encoding in encodings) {
                var var_name = encoding_name_to_const(encoding.type);
                output_stream.put_string(@"$(indent4)case \"$(encoding.type)\": return $var_name;\n");
            }
            output_stream.put_string(@"$(indent4)default: return IDENTITY_DATA;\n");
            output_stream.put_string(@"$(indent3)}\n");
            output_stream.put_string(@"$(indent2)}\n\n");

            // Write const arrays for each encoding
            foreach (var encoding in encodings) {
                var var_name = encoding_name_to_const(encoding.type);
                output_stream.put_string(@"$(indent2)private const uint8[] $var_name = {\n");
                write_byte_array(output_stream, encoding.data, indent3);
                output_stream.put_string(@"\n$(indent2)};\n\n");
            }

            // Close class
            output_stream.put_string(@"$(indent)}\n");

            // Close namespace if provided
            if (namespace_name != null) {
                output_stream.put_string("}\n");
            }

            output_stream.close();
        }

        private string encoding_name_to_const(string encoding_type) {
            // Convert encoding type to ALL_CAPS const name
            // e.g., "identity" -> "IDENTITY_DATA", "gzip" -> "GZIP_DATA", "br" -> "BR_DATA"
            var upper = encoding_type.replace("-", "_").up();
            return @"$(upper)_DATA";
        }

        private void write_byte_array(DataOutputStream stream, uint8[] data, string indent) throws Error {
            for (int i = 0; i < data.length; i++) {
                if (i > 0) {
                    if (i % 16 == 0) {
                        stream.put_string(",\n" + indent);
                    } else {
                        stream.put_string(", ");
                    }
                } else {
                    stream.put_string(indent);
                }
                stream.put_string("0x%02x".printf(data[i]));
            }
        }

        private void write_string_field(DataOutputStream stream, string value) throws Error {
            var bytes = value.data;
            if (bytes.length > 255) {
                throw new IOError.INVALID_DATA(@"String field too long: $(value.length) bytes (max 255)");
            }
            stream.put_byte((uint8)bytes.length);
            stream.write(bytes);
        }

        private static string make_pascal_case(string input) {
            // Remove extension first
            var name = input;
            var dot_pos = name.last_index_of(".");
            if (dot_pos > 0) {
                name = name.substring(0, dot_pos);
            }

            // Split on common separators and capitalize each word
            var result = new StringBuilder();
            var capitalize_next = true;
            
            foreach (var c in name.to_utf8()) {
                if (c == '-' || c == '_' || c == ' ' || c == '.') {
                    capitalize_next = true;
                } else {
                    if (capitalize_next) {
                        result.append(c.toupper().to_string());
                        capitalize_next = false;
                    } else {
                        result.append(c.to_string());
                    }
                }
            }
            
            return result.str;
        }

        private class EncodedData {
            public string type;
            public uint8[] data;

            public EncodedData(string type, owned uint8[] data) {
                this.type = type;
                this.data = (owned)data;
            }
        }
    }
}