#pragma once

#include <string>

#include <vector>

#include <iostream>

#include <sstream>

#include <locale>

#include <codecvt>

#include <regex>

#include <relpipe/reader/typedefs.h>

#include <relpipe/reader/TypeId.h>

#include <relpipe/reader/handlers/RelationalReaderStringHandler.h>

#include <relpipe/reader/handlers/AttributeMetadata.h>

namespace relpipe {

namespace out {

namespace tabular {

using namespace relpipe::reader;

class TabularPrefetchingHandler : public handlers::RelationalReaderStringHadler {

private:

	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.

	const char* ESC_BRIGHT = "\u001b[1m";

	const char* ESC_RED = "\u001b[31m";

	const char* ESC_GREEN = "\u001b[32m";

	const char* ESC_YELLOW = "\u001b[33m";

	const char* ESC_CYAN = "\u001b[36m";

	const char* ESC_RESET = "\u001b[0m";

	const char* ESC_HEADER = ESC_BRIGHT;

	const char* ESC_BORDER = ESC_GREEN;

	const char* ESC_VALUE = ESC_CYAN;

	const char* ESC_REPLACEMENT = ESC_RED;

	const char* INDENT = " "; // table indent from the left

	std::ostream &output;

	std::vector<TypeId> columnTypes;

	std::vector<string_t> columnTypeCodes;

	std::vector<string_t> columnNames;

	std::vector<integer_t> columnWidths;

	std::vector<string_t> values; // all values are saved here and processed at the end of the relation

	integer_t columnCount = 0;

	const string_t colorizeReplacement(const string_t &replacement, const char* valueColor) {

		return convertor.from_bytes(ESC_RESET) + convertor.from_bytes(ESC_REPLACEMENT) + replacement + convertor.from_bytes(ESC_RESET) + convertor.from_bytes(valueColor);

	}

	/**

	 * Sanitizes whitespace that could broke table layout.

	 * 

	 * TODO: sanitize also escape sequences and emoji (resp. properly measure their width)

	 * 

	 * @param value original value

	 * @param color value foreground color

	 * @return value with replaced whitespaces

	 */

	const string_t formatValue(const string_t &value, const char* color) {

		std::wstringstream result;

		result << convertor.from_bytes(color);

		for (auto & ch : value) {

			switch (ch) {

				case L'\n': result << colorizeReplacement(L"↲", color);

					break;

				case L'\r': result << colorizeReplacement(L"⏎", color);

					break;

				case L'\t': result << colorizeReplacement(L"↹", color);

					break;

				case L' ': result << colorizeReplacement(L"⎵", color);

					break;

				default: result << ch;

			}

		}

		result << convertor.from_bytes(ESC_RESET);

		return result.str();

	}

	void printHorizontalLine(const string_t &left, const string_t &middle, const string_t &right) {

		const string_t bar = L"─";

		// TODO: support also ASCII nostalgia:

		// border = border.replaceAll("─", "-");

		// border = border.replaceAll("│", "|");

		// border = border.replaceAll("[╭┬╮├┼┤╰┴╯]", "+");

		output << INDENT << ESC_BORDER;

		output << convertor.to_bytes(left);

		for (size_t c = 0; c < columnCount; c++) {

			integer_t width = columnWidths[c];

			for (integer_t w = 0; w < (width + 2); w++) output << convertor.to_bytes(bar); // 2 = left and right padding of the value

			if (c < (columnCount - 1)) output << convertor.to_bytes(middle);

		}

		output << convertor.to_bytes(right);

		output << ESC_RESET << std::endl;

	}

	void printCachedData() {

		// Compute column widths and paddings:

		vector<integer_t> paddings(columnCount);

		for (size_t i = 0; i < columnCount; i++) {

			string_t typeCode = columnTypeCodes[i];

			string_t columnName = columnNames[i];

			integer_t minWidth = columnName.size() + typeCode.size() + 3; // 3 = " ()" in "columnName (typeCode)"

			columnWidths[i] = max(columnWidths[i], minWidth);

			paddings[i] = columnWidths[i] - minWidth;

		}

		printHorizontalLine(L"╭", L"┬", L"╮");

		// Print column headers:

		output << INDENT << ESC_BORDER << "│" << ESC_RESET;

		for (size_t i = 0; i < columnCount; i++) {

			output << " " << convertor.to_bytes(formatValue(columnNames[i], ESC_HEADER));

			for (integer_t p = 0; p < paddings[i]; p++) {

				output << " ";

			}

			output << " (" << convertor.to_bytes(columnTypeCodes[i]) << ")";

			output << ESC_BORDER << " │" << ESC_RESET;

		}

		output << std::endl;

		printHorizontalLine(L"├", L"┼", L"┤");

		// Print particular rows:

		for (size_t i = 0; i < values.size(); i++) {

			integer_t columnIndex = i % columnCount;

			if (columnIndex == 0) output << INDENT << ESC_BORDER << "│" << ESC_RESET;

			string_t stringValue = values[i];

			integer_t padding = columnWidths[columnIndex] - stringValue.size();

			boolean_t alignRight = columnTypes[columnIndex] == TypeId::BOOLEAN || columnTypes[columnIndex] == TypeId::INTEGER;

			if (alignRight) for (integer_t p = 0; p < padding; p++) output << " ";

			output << " " << convertor.to_bytes(formatValue(stringValue, ESC_VALUE));

			if (!alignRight) for (integer_t p = 0; p < padding; p++) output << " ";

			output << ESC_BORDER << " │" << ESC_RESET;

			if (columnIndex == (columnCount - 1)) output << std::endl;

		}

		printHorizontalLine(L"╰", L"┴", L"╯");

		integer_t recordCount = values.size() / columnCount;

		output << ESC_YELLOW << "Record count: " << ESC_RESET << recordCount << std::endl;

		values.clear();

	}

public:

	TabularPrefetchingHandler(std::ostream& output) : output(output) {

	}

	void startRelation(string_t name, std::vector<handlers::AttributeMetadata> attributes) override {

		if (columnCount) printCachedData();

		output << ESC_RED << convertor.to_bytes(name) << ":" << ESC_RESET << endl;

		columnCount = attributes.size();

		columnTypes.resize(columnCount);

		columnTypeCodes.resize(columnCount);

		columnNames.resize(columnCount);

		columnWidths.resize(columnCount, 0);

		for (int i = 0; i < attributes.size(); i++) {

			columnNames[i] = attributes[i].getAttributeName();

			columnTypes[i] = attributes[i].getTypeId();

			columnTypeCodes[i] = attributes[i].getTypeName();

		}

	}

	void attribute(const string_t& value) override {

		integer_t i = values.size() % columnCount;

		values.push_back(value);

		columnWidths[i] = max(columnWidths[i], value.length());

	}

	void endOfPipe() {

		if (columnCount) printCachedData();

	}

};

}

}

}