#include "../include/Chatbar.hpp"
#include "../include/ResourceCache.hpp"
#include "../include/Settings.hpp"
#include "../include/Channel.hpp"
#include "../include/ChannelSidePanel.hpp"
#include "../include/UsersSidePanel.hpp"
#include "../include/Command.hpp"
#include <cmath>
#include <cstring>
#include <process.hpp>

using namespace std;

namespace dchat
{
    const float FONT_SIZE = 24;
    const float BOX_PADDING_X = 15.0f;
    const float BOX_PADDING_Y = 5.0f;
    const int BLINK_TIME_VISIBLE_MS = 500;
    const int BLINK_TIME_INVISIBLE_MS = 500;
    const float PADDING_SIDE = 20.0f;
    
    Chatbar::Chatbar() : 
        text("", ResourceCache::getFont("fonts/Roboto-Regular.ttf"), FONT_SIZE * Settings::getScaling()),
        caretIndex(0),
        focused(true)
    {
        text.setFillColor(sf::Color(240, 240, 240));
        background.setFillColor(sf::Color(60, 60, 60));
    }
    
    void Chatbar::addChar(sf::Uint32 codePoint)
    {
        auto str = text.getString();
        str.insert(caretIndex, codePoint);
        text.setString(str);
        ++caretIndex;
        caretOffset = text.findCharacterPos(caretIndex) - text.getPosition();
        blinkTimer.restart();
    }
    
    void Chatbar::addString(const string &strToAdd)
    {
        if(strToAdd.empty()) return;
        auto str = text.getString();
        str.insert(caretIndex, sf::String::fromUtf8(strToAdd.begin(), strToAdd.end()));
        text.setString(str);
        caretIndex += strToAdd.size();
        caretOffset = text.findCharacterPos(caretIndex) - text.getPosition();
        blinkTimer.restart();
    }
    
    const sf::String& Chatbar::getString() const
    {
        return text.getString();
    }
    
    void Chatbar::removePreviousChar()
    {
        if(caretIndex > 0)
        {
            auto str = text.getString();
            str.erase(caretIndex - 1);
            text.setString(str);
            --caretIndex;
            caretOffset = text.findCharacterPos(caretIndex) - text.getPosition();
        }
        blinkTimer.restart();
    }
    
    void Chatbar::removeNextChar()
    {
        if(caretIndex < text.getString().getSize())
        {
            auto str = text.getString();
            str.erase(caretIndex);
            text.setString(str);
        }
        blinkTimer.restart();
    }
    
    void Chatbar::clear()
    {
        text.setString("");
        caretIndex = 0;
        caretOffset.x = 0.0f;
        caretOffset.y = 0.0f;
        blinkTimer.restart();
    }
    
    void Chatbar::moveCaretLeft()
    {
        caretIndex = max(0, caretIndex - 1);
        // TODO: Use glyph size to optimize this, no need to iterate all glyphs
        caretOffset = text.findCharacterPos(caretIndex) - text.getPosition();
        blinkTimer.restart();
    }
    
    void Chatbar::moveCaretRight()
    {
        caretIndex = min((int)text.getString().getSize(), caretIndex + 1);
        caretOffset = text.findCharacterPos(caretIndex) - text.getPosition();
        blinkTimer.restart();
    }
    
    bool Chatbar::isFocused() const
    {
        return focused;
    }
    
    class ArgParseException : public std::runtime_error
    {
    public:
        ArgParseException(const string &errMsg) : std::runtime_error(errMsg) {}
    };
    
    string stringRemoveQuotes(const StringView &str)
    {
        string result;
        result.reserve(str.size);
        for(usize i = 0; i < str.size; ++i)
        {
            char c = str[i];
            if(c != '\'' && c != '"')
                result += c;
        }
        return result;
    }
    
    vector<string> splitCommandArgs(const StringView &str)
    {
        vector<string> result;
        ssize offset = 0;
        char quoteChar = '\0';
        
        for(ssize i = 0; i < str.size; ++i)
        {
            char c = str[i];
            if(c == '\'' || c == '"')
            {
                if(c == quoteChar)
                    quoteChar = '\0';
                else
                    quoteChar = c;
            }
            else if(quoteChar == '\0' && c == ' ')
            {
                ssize substrLength = i - offset;
                if(substrLength > 0)
                {
                    StringView substrView(str.data + offset, substrLength);
                    string substr = stringRemoveQuotes(substrView);
                    if(!substr.empty())
                        result.emplace_back(move(substr));
                }
                offset = i + 1;
            }
        }
        
        if(quoteChar != '\0')
        {
            string errMsg = "Reached end of command before end of quote (";
            errMsg += quoteChar;
            errMsg += ")";
            throw ArgParseException(errMsg);
        }
        
        ssize strLeft = str.size - offset;
        if(strLeft > 0)
        {
            StringView substrView(str.data + offset, strLeft);
            string substr = stringRemoveQuotes(substrView);
            if(!substr.empty())
                result.emplace_back(move(substr));
        }
        return result;
    }
    
    void Chatbar::processChatCommand(const StringView &cmd)
    {
        vector<string> args;
        try
        {
            args = splitCommandArgs(cmd);
        }
        catch(ArgParseException &e)
        {
            fprintf(stderr, "Failed to parse command arguments, reason: %s\n", e.what());
            return;
        }
        
        if(!args.empty())
        {
            string command = args.front();
            args.erase(args.begin());
            if(!Command::call(command, args))
                fprintf(stderr, "No such command: %s\n", command.c_str());
        }
    }
    
    string getClipboard()
    {
        string result;
        TinyProcessLib::Process process("xsel -o -b", "", [&result](const char *bytes, size_t n)
        {
            result.append(bytes, n);
        });
        if(process.get_exit_status() != 0)
            fprintf(stderr, "Failed to get clipboard content\n");
        return result;
    }
    
    void Chatbar::processEvent(const sf::Event &event, Channel *channel)
    {
        if(!focused) return;
        
        if(event.type == sf::Event::TextEntered)
        {
            if(event.text.unicode == 8) // backspace
                removePreviousChar();
            else if(event.text.unicode == 13) // enter
            {
                if(!getString().isEmpty())
                {
                    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Key::LShift) || sf::Keyboard::isKeyPressed(sf::Keyboard::Key::RShift))
                    {
                        addChar('\n');
                    }
                    else
                    {
                        auto chatbarMsgUtf8 = getString().toUtf8();
                        string msg;
                        msg.resize(chatbarMsgUtf8.size());
                        memcpy(&msg[0], chatbarMsgUtf8.data(), chatbarMsgUtf8.size());
                        if(msg[0] == '/')
                            processChatCommand(StringView(msg.data() + 1, msg.size() - 1));
                        else
                            channel->addMessage(msg);
                        clear();
                    }
                }
            }
            else if(event.text.unicode == 127) // delete
            {
                removeNextChar();
            }
            else if(event.text.unicode == 22) // ctrl+v
            {
                // TODO: Instead of calling external xsel, use sfml clipboard functionality (in new sfml version)
                string clipboard = getClipboard();
                addString(clipboard);
            }
            else
            {
                addChar(event.text.unicode);
            }
        }
        else if(event.type == sf::Event::KeyPressed)
        {
            if(event.key.code == sf::Keyboard::Left)
                moveCaretLeft();
            else if(event.key.code == sf::Keyboard::Right)
                moveCaretRight();
        }
    }
    
    void Chatbar::draw(sf::RenderWindow &window)
    {
        auto windowSize = window.getSize();
        
        sf::Vector2f backgroundSize(floor(windowSize.x - ChannelSidePanel::getWidth() - UsersSidePanel::getWidth() - PADDING_SIDE * 2.0f), floor(text.getCharacterSize() * 1.7f + BOX_PADDING_Y * 2.0f));
        sf::Vector2f backgroundPos(floor(ChannelSidePanel::getWidth() + PADDING_SIDE), floor(windowSize.y - backgroundSize.y - 20.0f));
        background.setSize(backgroundSize);
        background.setPosition(backgroundPos);
        text.setPosition(floor(backgroundPos.x + BOX_PADDING_X), floor(backgroundPos.y + backgroundSize.y * 0.5f - text.getCharacterSize() * 0.5f));
        
        window.draw(background);
        window.draw(text);
        
        int blinkElapsedTime = blinkTimer.getElapsedTime().asMilliseconds();
        if(focused && blinkElapsedTime <= BLINK_TIME_VISIBLE_MS)
        {
            sf::RectangleShape caretShape(sf::Vector2f(2.0f, backgroundSize.y - BOX_PADDING_Y * 2.0f));
            caretShape.setPosition(floor(text.getPosition().x + caretOffset.x), (caretOffset.y + backgroundPos.y + BOX_PADDING_Y));
            window.draw(caretShape);
        }
        
        if(blinkElapsedTime > BLINK_TIME_VISIBLE_MS + BLINK_TIME_INVISIBLE_MS)
            blinkTimer.restart();
    }
}