#include <cctype>
#include <cstdint>
#include <groundvm.h>
#include <vector>
#include <string>
#include <fstream>
#include <iostream>
#include <sstream>
#include <optional>
#include <variant>

namespace HighGround {

    int tmpIdIterator = 0;

    namespace Parser {

        enum class HGNodeType {
            Add, Subtract, Equal, Set, While, If, Value, Identifier, None, Root, CodeBlock
        };

        enum class HGDataType {
            Int, String, Double, Bool, Char, None
        };

        class HGNode;

        class HGGroundCodeBlock {
            public:
            std::vector<GroundInstruction> code;
            HGGroundCodeBlock() = default;
        };

        class HGData {
            std::variant<int64_t, std::string, double, bool, char> data;
            public:
            HGDataType type = HGDataType::Int;
            HGData() = default;
            HGData(int64_t in) : data(in) {}
            std::optional<int64_t> getInt() {
                if (type == HGDataType::Int) {
                    return std::get<int64_t>(data);
                } else {
                    return {};
                }
            }
        };

        class HGNode {
            HGNodeType nodeType = HGNodeType::None;
            HGData data;
            std::vector<HGNode> children;
            public:
            std::string outputId;
            HGNode(HGNodeType nodeType) : nodeType(nodeType) {}
            HGNode(HGNodeType nodeType, HGData data) : nodeType(nodeType), data(data) {}
            HGNode() = default;
            void addNode(HGNode in) {
                children.push_back(in);
            }
            void setValue(HGData in) {
                data = in;
            }
            const std::vector<HGGroundCodeBlock> generateCode() {
                std::vector<HGGroundCodeBlock> code;
                for (auto& child : children) {
                    auto childCode = child.generateCode();
                    code.insert(code.end(), childCode.begin(), childCode.end());
                }
                switch (nodeType) {
                    case HGNodeType::Value: {
                        outputId = "tmp_" + std::to_string(tmpIdIterator++);
                        HGGroundCodeBlock codeBlock;
                        GroundInstruction gi = groundCreateInstruction(SET);
                        groundAddReferenceToInstruction(&gi, groundCreateReference(DIRREF, outputId.data()));
                        switch (data.type) {
                            case HGDataType::Int: {
                                auto dataopt = data.getInt();
                                if (dataopt) {
                                    groundAddValueToInstruction(&gi, groundCreateValue(INT, dataopt.value()));
                                }
                            }
                        }
                        codeBlock.code.push_back(gi);
                        code.push_back(codeBlock);
                        break;
                    }
                    default: {
                        std::cout << "Not implemented yet\n";
                    }
                }
                return code;
            }
            
        };

        class Parser {
            std::vector<std::string> tokensToParse;
            size_t current;
            size_t size;

            std::optional<std::string> peek(int ahead = 1) {
                if (current + ahead < size) {
                    return tokensToParse[current + ahead];
                } else {
                    return {};
                }
            }

            std::optional<std::string> consume() {
                if (current < size) {
                    return tokensToParse[current++];
                } else {
                    return {};
                }
            }

            bool isInt(std::string in) {
                for (const char& c : in) {
                    if (!std::isdigit(c)) {
                        return false;
                    }
                }
                return true;
            }
            bool isDouble(std::string in) {
                bool foundDot = false;
                for (const char& c : in) {
                    if (!std::isdigit(c)) {
                        if (!foundDot && c == '.') {
                            foundDot = true;
                            continue;
                        }
                        return false;
                    }
                }
                return true;
            }

            HGDataType getDataType(std::string in) {
                if (isInt(in)) {
                    return HGDataType::Int;
                }
                if (isDouble(in)) {
                    return HGDataType::Double;
                }
                return HGDataType::None;
            }

            HGNodeType getNodeType(std::string in) {
                if (getDataType(in) != HGDataType::None) {
                    return HGNodeType::Value;
                }
                return HGNodeType::None;
            }

            public:
            Parser(std::vector<std::string> in) : tokensToParse(in) {}

            HGNode parse() {
                current = 0;
                size = tokensToParse.size();
                HGNode rootNode(HGNodeType::Root);
                while (auto tokenopt = consume()) {
                    std::string token = tokenopt.value();
                    switch (getNodeType(token)) {
                        case HGNodeType::Value: {
                            switch (getDataType(token)) {
                                case HGDataType::Int: {
                                    std::cout << "We have an int\n";
                                    HGNode intNode(HGNodeType::Value);
                                    intNode.setValue(std::stoll(token));
                                    rootNode.addNode(intNode);
                                    break;
                                }
                            }
                            break;
                        }
                    }
                }
                return rootNode;
            }
        };

        GroundProgram assembleProgram(HGNode& rootNode) {
            GroundProgram gp = groundCreateProgram();
            auto code = rootNode.generateCode();
            for (int i = 0; i < code.size(); i++) {
                for (const auto& inst : code[i].code) {
                    groundAddInstructionToProgram(&gp, inst);
                }
            }
            groundAddInstructionToProgram(&gp, groundCreateInstruction(PAUSE));
            return gp;
        }

    } // namespace Parser
    
    class Lexer {
        std::string input;
        size_t size;
        size_t current;

        std::optional<char> peek(int ahead = 1) {
            if (current + ahead < size) {
                return input[current + ahead];
            } else {
                return {};
            }
        }

        std::optional<char> consume() {
            if (current < size) {
                return input[current++];
            } else {
                return {};
            }
        }

        public:
        Lexer(std::string in) : input(in), size(in.size()) {};
        std::vector<std::string> lex() {
            current = 0;
            std::vector<std::string> tokens;
            std::string buf;
            while (auto copt = consume()) {
                char c = copt.value();
                switch (c) {
                    // tokens which are not followed by anything
                    case '(':
                    case ')':
                    case '{':
                    case '}': 
                    {
                        if (!buf.empty()) {
                            tokens.push_back(buf);
                            buf.clear();
                        }
                        tokens.push_back(std::string(1, c));
                        break;
                    }
                    // tokens which may be followed by either themselves
                    // or an equals sign
                    case '+':
                    case '-':
                    {
                        std::string newToken(1, c);
                        auto tokenopt = peek();
                        if (tokenopt) {
                            char token = tokenopt.value();
                            if (token == c || token == '=') {
                                newToken += token;
                                consume();
                            }
                        }
                        if (!buf.empty()) {
                            tokens.push_back(buf);
                            buf.clear();
                        }
                        tokens.push_back(newToken);
                        break;
                    }
                    // tokens which may be followed by an equals sign
                    case '*':
                    case '/':
                    case '=':
                    {
                        std::string newToken(1, c);
                        auto tokenopt = peek();
                        if (tokenopt) {
                            char token = tokenopt.value();
                            if (token == '=') {
                                newToken += token;
                                consume();
                            }
                        }
                        if (!buf.empty()) {
                            tokens.push_back(buf);
                            buf.clear();
                        }
                        tokens.push_back(newToken);
                        break;
                    }
                    // tokens which do not need to be included
                    case ' ':
                    case '\n':
                    {
                        if (!buf.empty()) {
                            tokens.push_back(buf);
                            buf.clear();
                        }
                        break;
                    }
                    default: 
                    {
                        buf += c;
                    }
                }
            }

            if (!buf.empty()) {
                tokens.push_back(buf);
            }
            return tokens;
        }

    };


} // namespace HighGround


int main(int argc, char** argv) {
    if (argc < 2) {
        std::cout << "Usage: " << argv[0] << " (file)\n"; 
        exit(1);
    }
    std::ifstream file(argv[1]);
    std::ostringstream ss;
    ss << file.rdbuf();
    auto lexed = HighGround::Lexer(ss.str()).lex();
    auto parsed = HighGround::Parser::Parser(lexed).parse();
    GroundProgram program = HighGround::Parser::assembleProgram(parsed);
    groundRunProgram(&program);
}