#include "../include/ninja/Ninja.hpp"
#include <cassert>

namespace ninja
{
    static std::string joinArgs(const std::vector<NinjaArg> &args)
    {
        std::string result;
        for(const NinjaArg &arg : args)
        {
            if(!result.empty())
                result += ' ';

            NinjaArg::Type argType = arg.type;
            if(!arg.arg.empty() && arg.arg[0] == '$')
                argType = NinjaArg::Type::RAW;
            
            switch(argType)
            {
                case NinjaArg::Type::VALUE:
                {
                    result += '\"' + arg.arg + '\"';
                    break;
                }
                case NinjaArg::Type::VARIABLE:
                {
                    result += '$' + arg.arg;
                    break;
                }
                case NinjaArg::Type::RAW:
                {
                    result += arg.arg;
                    break;
                }
            }
        }
        return result;
    }

    static bool isAlpha(char c)
    {
        return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
    }

    static bool isNum(char c)
    {
        return c >= '0' && c <= '9';
    }

    static bool isAlnum(char c)
    {
        return isAlpha(c) || isNum(c);
    }

    static bool isValidName(const std::string &name)
    {
        if(name.empty())
            return false;

        if(name.size() > 100)
            return false;

        if(!isAlpha(name[0]) && name[0] != '_')
            return false;

        for(int i = 1; i < name.size(); ++i)
        {
            if(!isAlnum(name[i]) && name[i] != '_')
                return false;
        }

        return true;
    }

    static std::string escape(const std::string &str)
    {
        std::string result;
        result.reserve(str.size());
        for(char c : str)
        {
            if(c == '\n')
                result += "$\n";
            else if(c == '$')
                result += "$$";
            else if(c == ' ')
                result += "$ ";
            else if(c == ':')
                result += "$:";
            else
                result += c;
        }
        return result;
    }

    static std::string combine_escape(const std::vector<std::string> &strs)
    {
        std::string result;
        for(const std::string &str : strs)
        {
            if(!result.empty())
                result += ' ';
            result += escape(str);
        }
        return result;
    }

    NinjaVariable::NinjaVariable(const std::string &_name) : 
        name(_name)
    {
        if(!isValidName(name))
            throw NinjaException(NinjaError::INVALID_NAME, "Invalid variable name, has to match [a-zA-Z_]{1}[a-zA-Z0-9_]{0,98}");
    }

    NinjaRule::NinjaRule(NinjaBuildFile *_buildFile, const std::string &_name, const std::string &_command) : 
        buildFile(_buildFile),
        name(_name),
        command(_command)
    {
        assert(buildFile);
    }

    NinjaBuildFile::~NinjaBuildFile()
    {
        for(auto &rule : rules)
        {
            delete rule.second;
        }

        for(NinjaBuild *build : builds)
        {
            delete build;
        }
    }

    NinjaBuild* NinjaRule::build(const std::string &in, const std::string &out, const std::vector<ninja::NinjaArgValue> &additionalArgs, const std::vector<NinjaBuild*> &dependsOnBuilds)
    {
        return buildFile->build(this, in, out, additionalArgs, dependsOnBuilds);
    }

    NinjaBuild* NinjaRule::build(const std::vector<std::string> &in, const std::string &out, const std::vector<ninja::NinjaArgValue> &additionalArgs, const std::vector<NinjaBuild*> &dependsOnBuilds)
    {
        return buildFile->build(this, in, out, additionalArgs, dependsOnBuilds);
    }

    void NinjaBuildFile::defineGlobalVariable(const std::string &name, const std::string &value)
    {
        if(!isValidName(name))
            throw NinjaException(NinjaError::INVALID_NAME, "Invalid global variable name, has to match [a-zA-Z_]{1}[a-zA-Z0-9_]{0,98}");

        auto it = globalVariables.find(name);
        if(it != globalVariables.end())
            throw NinjaException(NinjaError::VARIABLE_ALREADY_DEFINED, "Global variable already defined: " + name);
        globalVariables[name] = value;
    }

    NinjaRule* NinjaBuildFile::createRule(const std::string &name, const std::vector<NinjaArg> &commandArgs)
    {
        if(!isValidName(name))
            throw NinjaException(NinjaError::INVALID_NAME, "Invalid rule name, has to match [a-zA-Z_]{1}[a-zA-Z0-9_]{0,98}");

        auto it = rules.find(name);
        if(it != rules.end())
            throw NinjaException(NinjaError::RULE_ALREADY_DEFINED, "Rule already defined: " + name);

        NinjaRule *rule = new NinjaRule(this, name, joinArgs(commandArgs));
        rules[name] = rule;
        return rule;
    }

    NinjaBuild* NinjaBuildFile::build(const NinjaRule *rule, const std::string &in, const std::string &out, const std::vector<ninja::NinjaArgValue> &additionalArgs, const std::vector<NinjaBuild*> &dependsOnBuilds)
    {
        NinjaBuild *build = new NinjaBuild { rule, { in }, escape(out), additionalArgs, dependsOnBuilds };
        builds.push_back(build);
        return build;
    }

    NinjaBuild* NinjaBuildFile::build(const NinjaRule *rule, const std::vector<std::string> &in, const std::string &out, const std::vector<ninja::NinjaArgValue> &additionalArgs, const std::vector<NinjaBuild*> &dependsOnBuilds)
    {
        NinjaBuild *build = new NinjaBuild { rule, in, escape(out), additionalArgs, dependsOnBuilds };
        builds.push_back(build);
        return build;
    }

    std::string NinjaBuildFile::generate() const
    {
        std::string result;
        for(const auto &globalVar : globalVariables)
        {
            result += globalVar.first;
            result += " = ";
            result += globalVar.second;
            result += '\n';
        }

        if(!globalVariables.empty())
            result += '\n';
        
        for(const auto &rule : rules)
        {
            result += "rule ";
            result += rule.first;
            result += "\n  command = ";
            result += rule.second->command;
            if(!rule.second->depFile.empty())
            {
                result += "\n  depfile = ";
                result += rule.second->depFile;
            }
            if(!rule.second->deps.empty())
            {
                result += "\n  deps = ";
                result += rule.second->deps;
            }
            result += "\n\n";
        }

        result += "build always: phony\n\n";

        for(const NinjaBuild *build : builds)
        {
            result += "build ";
            result += build->out;
            result += ": ";
            result += build->rule->name;
            result += ' ';
            result += combine_escape(build->in);

            if(!build->dependsOnBuilds.empty())
            {
                result += " ||";
                for(const NinjaBuild *dependsOnBuild : build->dependsOnBuilds)
                {
                    result += ' ' + dependsOnBuild->out;
                }
            }

            if(build->alwaysRun)
                result += " | always";

            for(const NinjaArgValue &additionalArg : build->additionalArgs)
            {
                result += "\n  ";
                result += additionalArg.arg.name;
                result += " = ";
                result += additionalArg.value;

            }
            result += "\n\n";
        }
        return result;
    }
}