#define KEYWORD_ENTITY      "entity"
#define KEYWORD_BRUSH       "brush"
#define KEYWORD_VERTICES    "vertices"
#define KEYWORD_FACES       "faces"
#define KEYWORD_GLOBAL      "global"
#define KEYWORD_PREFAB      "prefab"

#include "oopless-parser.hpp"
#include "brushdef.hpp"
#include "EntityConverter.hpp"
#include <sstream>
#include <iostream>
using namespace std;

bool is_ebrush(std::vector<std::string> input) {
// defines are only used in this function.
#define KEYWORD_ENTBRUSH1 "type Teleporter"
#define KEYWORD_ENTBRUSH2 "type JumpPad"
    for (const string &str : input) {
        if (str.compare(KEYWORD_ENTBRUSH1) == 0 ||
            str.compare(KEYWORD_ENTBRUSH2) == 0) {
                return true;
        }
    }
    return false;
}

// place holding functions to test proper control flow.
bool write(const struct TBrush &geometry, 
           ofstream &fout,
           void (*b) (stringstream &, const vector<TPlanePoints> &)) {
    bool ok = true;
    if (geometry.m_Vertices.size() < 1) {
        cerr << "error: geometry has no vertices" << endl;
        ok = false;
    }
    if (geometry.m_Faces.size() < 1) {
        cerr << "error: geometry has no faces"<< endl;
        ok = false;
    }
    if (ok) {
        fout << GetBrushString(geometry, b);
    }
    return ok;
}

void write(const vector<string> &entity, ofstream &fo) {
    ;
}

// entities will vary widely depending on their type and available flags.
// for now, acquire entity data, and handle their conversion in the write methods.
vector<string> get_entity(ifstream &f) {
    vector<string> output;
    string line;
    unsigned int pos = f.tellg();
    while (getline(f, line)) {
        // stop when
        // entity or a prefab keyword
        // brush keyword and the entity is not of the type teleporter or jumppad.
        if ((line.find(KEYWORD_ENTITY) != string::npos || 
            line.find(KEYWORD_PREFAB) != string::npos) || (
            line.find(KEYWORD_BRUSH) != string::npos && !is_ebrush(output))) {
                f.seekg(pos);
                return output;
        } else {
            output.push_back(line);
        }
        pos = f.tellg();
    }
}

vector<Eigen::Vector3f> parse_vertices(ifstream &f) {
#define FIRSTCH(x) x[0]
    vector<Eigen::Vector3f> output;
    string line;
    unsigned int pos = f.tellg();
    while(getline(f, line)) {
        if (line.find(KEYWORD_FACES) != string::npos || 
            line.find(KEYWORD_BRUSH) != string::npos ||
            line.find(KEYWORD_ENTITY) != string::npos ||
            line.find(KEYWORD_PREFAB) != string::npos) {
                f.seekg(pos);
                return output;
        } else {
            Eigen::Vector3f v;
            stringstream ss(line);
            string vdata;
            unsigned int i = 0;
            while (ss >> vdata) {
                if (isdigit(FIRSTCH(vdata)) || FIRSTCH(vdata) == '-') {
                    double dvalue = stod(vdata);
                    v[i] = (float)dvalue;
                }
                // note: this prevents the index growing out of vector capacity
                // alternatively can throw an exception when that happens instead
                // to make it clear that an illegal line has been hit.
                i = (i + 1) % 3;
            }
            output.push_back(v);
        }
        pos = f.tellg();
    }
    return output;
}

vector<struct TFace> parse_face(ifstream &f) {
#define FIRSTCH(x) x[0]
#define SECONDCH(x) x[1]
    // it is possible for the next line to be unrelated to faces
    // so it is needed to reset the stream prior to reading 
    // the new label, e.g '\tbrush'.
    vector<struct TFace> output;
    string line;
    unsigned int pos = f.tellg();
    while(getline(f, line)) {
        if (line.find(KEYWORD_VERTICES) != string::npos || 
            line.find(KEYWORD_BRUSH) != string::npos ||
            line.find(KEYWORD_ENTITY) != string::npos ||
            line.find(KEYWORD_PREFAB) != string::npos ||
            line.find(KEYWORD_GLOBAL) != string::npos) {
                f.seekg(pos);
                return output;
        } else {
                struct TFace x;
                float *f = &x.m_fXOffset;;
                stringstream ss(line);
                string fdata;
                bool hex = false;
                unsigned int i = 0;
                while (ss >> fdata) {
                    if (i < 5) {
                        if (isdigit(FIRSTCH(fdata)) || FIRSTCH(fdata) == '-') {
                            double dvalue = stod(fdata);
                            *f = (float)dvalue;
                            f++;
                        }
                        // note: if there is a non-digit in the first 5 fields
                        // then it qualifies as an illegal line.
                    } else if (4 < i && i < 8) {
                            x.m_Indices.push_back(stoi(fdata));
                    } else if (8 <= i) {
                        if (!hex && fdata.length() > 1) {
                            if (SECONDCH(fdata) == 'x') {
                            // this is the unidentified hex digit.
                            // out of range for stoi
                                x.hex = strtoul(fdata.c_str(), NULL, 16);
                                hex = true; 
                            }
                        } else if (!hex) {
                            x.m_Indices.push_back(stoi(fdata));
                        } else if (hex) {
                            x.m_Material = fdata;
                        } else {
                            ;
                        }
                    }
                    i++;
                } // end, per field iteration
                output.push_back(x);
        } // end else case, if line did not contain other keywords 
        pos = f.tellg();
    } // end, per line iteration
    // the odd case when the map file ends with a face indent.
    return output;
}

struct TBrush parse_brush(ifstream &f) {
    struct TBrush output;
    string l;
    getline(f, l);
    // wip: note must return the entire brush, adjust control flow
    if (l.find(KEYWORD_VERTICES) != string::npos) {
        output.m_Vertices = parse_vertices(f);        
    } 
    getline(f, l);
    if (l.find(KEYWORD_FACES) != string::npos) {
        output.m_Faces = parse_face(f);
    }
    return output;
}

void parse_prefab(ifstream &f, 
                  ofstream &out, 
                  void (*b) (stringstream &, const vector<TPlanePoints> &)) {
    string l;
    getline(f, l);
    if (l.find(KEYWORD_BRUSH) != string::npos) {
        write(parse_brush(f), out, b);
    } else if (l.find(KEYWORD_ENTITY) != string::npos) {
        write(get_entity(f), out);
    }
}

// note: can't use a single function pointer for variadic overloaded write function?
bool convertmap(const char * const infile, 
                const char * const outfile,
                void (*brushdef) (stringstream &, const vector<TPlanePoints> &)) {
    ifstream fin;
    fin.open(infile);
    if (!fin.good()){
        cerr << "error: failed to open input file" << endl;
        return false;
    }
    ofstream fout;
    fout.open(outfile);
    if (!fout.good()) {
        cerr << "error: failed to open output file" << endl;
        return false;
    }
    fout << "{\n"
         << "\"classname\" \"worldspawn\"" << endl;
    string line;
    while (getline(fin, line)) {
        if (line.find(KEYWORD_PREFAB) != string::npos ||
            line.find(KEYWORD_GLOBAL) != string::npos) {
                parse_prefab(fin, fout, brushdef);
        } else if (line.find(KEYWORD_ENTITY) != string::npos) {
                write(get_entity(fin), fout);
        } else if (line.find(KEYWORD_BRUSH) != string::npos) {
                write(parse_brush(fin), fout, brushdef);
        }
    }
    fout << "}" << endl;
    fin.close();
    fout.close();
    return true;
}