#pragma once

#include <iostream>
#include <fstream>
#include <sstream> // MSVC need this to use std::getline
#include <cstring>
#include <vector>

#include "nasal.h"

struct span {
    u32 begin_line;
    u32 begin_column;
    u32 end_line;
    u32 end_column;
    string file;
};

#ifdef _WIN32
#include <windows.h> // use SetConsoleTextAttribute
struct for_reset {
    CONSOLE_SCREEN_BUFFER_INFO scr;
    for_reset() {
        GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &scr);
    }
} reset_ter_color;
#endif

std::ostream& back_white(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 0xf0);
#else
    s<<"\033[7m";
#endif
    return s;
}

std::ostream& red(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 0x0c);
#else
    s<<"\033[91;1m";
#endif
    return s;
}

std::ostream& cyan(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 0x03);
#else
    s<<"\033[36;1m";
#endif
    return s;
}

std::ostream& orange(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 0x0e);
#else
    s<<"\033[93;1m";
#endif
    return s;
}

std::ostream& white(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), 0x0f);
#else
    s<<"\033[0m\033[1m";
#endif
    return s;
}

std::ostream& reset(std::ostream& s) {
#ifdef _WIN32
    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), reset_ter_color.scr.wAttributes);
#else
    s<<"\033[0m";
#endif
    return s;
}

class flstream {
protected:
    string file;
    std::vector<string> res;
public:
    flstream():file("") {}
    void load(const string&);
    const string& operator[](usize n) const {return res[n];}
    const string& name() const {return file;}
    usize size() const {return res.size();}
};

class error:public flstream {
private:
    u32 cnt; // counter for errors

    string identation(usize len) {
        return string(len,' ');
    }
    string leftpad(u32 num, usize len) {
        string tmp=std::to_string(num);
        while(tmp.length()<len) {
            tmp=" "+tmp;
        }
        return tmp;
    }
public:
    error():cnt(0) {}
    void fatal(const string&, const string&);
    void err(const string&, const string&);
    void err(const string&, const span&, const string&);

    void chkerr() const {
        if (cnt) {
            std::exit(1);
        }
    }
};


void flstream::load(const string& f) {
    if (file==f) { // don't need to load a loaded file
        return;
    } else {
        file=f;
    }

    res.clear();
    std::ifstream in(f, std::ios::binary);
    if (in.fail()) {
        std::cerr<<red<<"src: "<<reset<<"cannot open <"<<f<<">\n";
        std::exit(1);
    }
    
    while(!in.eof()) {
        string line;
        std::getline(in, line);
        res.push_back(line);
    }
}

void error::fatal(const string& stage, const string& info) {
    std::cerr<<red<<stage<<": "<<white<<info<<reset<<"\n";
    if (file.length()) {
        std::cerr<<cyan<<" --> "<<red<<file<<reset<<"\n\n";
    } else {
        std::cerr<<reset<<"\n";
    }
    std::exit(1);
}

void error::err(const string& stage, const string& info) {
    ++cnt;
    std::cerr<<red<<stage<<": "<<white<<info<<reset<<"\n";
    if (file.length()) {
        std::cerr<<cyan<<" --> "<<red<<file<<reset<<"\n\n";
    } else {
        std::cerr<<reset<<"\n";
    }
}

void error::err(const string& stage, const span& loc, const string& info) {
    // load error occurred file into string lines
    load(loc.file);

    ++cnt;

    std::cerr
    <<red<<stage<<": "<<white<<info<<reset<<"\n"<<cyan<<"  --> "
    <<red<<loc.file<<":"<<loc.begin_line<<":"<<loc.begin_column+1<<reset<<"\n";

    const usize maxlen=std::to_string(loc.end_line).length();
    const string iden=identation(maxlen);

    for(u32 line=loc.begin_line; line<=loc.end_line; ++line) {
        if (!line) {
            continue;
        }

        if (loc.begin_line<line && line<loc.end_line) {
            if (line==loc.begin_line+1) {
                std::cerr<<cyan<<iden<<" | "<<reset<<"...\n"<<cyan<<iden<<" | "<<reset<<"\n";
            }
            continue;
        }

        // if this line has nothing, skip
        if (!res[line-1].length() && line!=loc.end_line) {
            continue;
        }

        const string& code=res[line-1];
        std::cerr<<cyan<<leftpad(line, maxlen)<<" | "<<reset<<code<<"\n";
        // output underline
        std::cerr<<cyan<<iden<<" | "<<reset;
        if (loc.begin_line==loc.end_line) {
            for(u32 i=0; i<loc.begin_column; ++i) {
                std::cerr<<char(" \t"[code[i]=='\t']);
            }
            for(u32 i=loc.begin_column ;i<loc.end_column; ++i) {
                std::cerr<<red<<(code[i]=='\t'?"^^^^":"^")<<reset;
            }
        } else if (line==loc.begin_line) {
            for(u32 i=0; i<loc.begin_column; ++i) {
                std::cerr<<char(" \t"[code[i]=='\t']);
            }
            for(u32 i=loc.begin_column; i<code.size(); ++i) {
                std::cerr<<red<<(code[i]=='\t'?"^^^^":"^")<<reset;
            }
        } else if (loc.begin_line<line && line<loc.end_line) {
            for(u32 i=0; i<code.size(); ++i) {
                std::cerr<<red<<(code[i]=='\t'?"^^^^":"^");
            }
        } else {
            for(u32 i=0; i<loc.end_column; ++i) {
                std::cerr<<red<<(code[i]=='\t'?"^^^^":"^");
            }
        }
        if (line==loc.end_line) {
            std::cerr<<reset;
        } else {
            std::cerr<<reset<<"\n";
        }
    }
    std::cerr<<"\n\n";
}