/**
 * The MIT License (MIT)
 * Copyright (c) <2015> <carriez.md@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#ifndef INI_HPP
#define INI_HPP

#include <algorithm>
#include <cassert>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <stdexcept>
#include <string>
#include <vector>

namespace ini
{
  struct Level
  {
    Level() : parent(nullptr), depth(0)
    {
    }
    Level(Level *p) : parent(p), depth(0)
    {
    }

    typedef std::list< std::pair< std::string, std::string > > value_map_t;
    typedef std::map< std::string, Level > section_map_t;
    typedef std::list< section_map_t::const_iterator > sections_t;
    value_map_t values;
    section_map_t sections;
    sections_t ordered_sections;
    Level *parent;
    size_t depth;

    static std::string default_value;

    const std::string &operator[](const std::string &name)
    {
      for(const auto &itr : values)
        if(itr.first == name)
          return itr.second;
      return default_value;
    }
    Level &
    operator()(const std::string &name)
    {
      return sections[name];
    }
  };

  class Parser
  {
   public:
    Parser(const std::string &fname) : Parser(fname.c_str())
    {
    }
    Parser(const char *fn);
    Parser(std::istream &f) : f_(&f), ln_(0)
    {
      parse(top_);
    }
    Level &
    top()
    {
      return top_;
    }
    void
    dump(std::ostream &s)
    {
      dump(s, top(), "");
    }
    void
    print()
    {
      dump(std::cout, top(), "");
    }

    bool
    write(const std::string filename)
    {
      // this->print();
      // printf("parser::Write\n");
      std::ofstream s;
      s.open(filename);
      if(!s.is_open())
      {
        printf("parser::Write - can't open\n");
        err("Cant open");
        return false;
      }
      // reset read
      // printf("parser::Write - committing\n");
      this->commitStream(s);
      s.close();
      return true;
    }

    void
    commitStream(std::ostream &s)
    {
      // printf("parser::commitStream - seekd\n");
      this->ln_ = 0;
      this->f_->clear();
      this->f_->seekg(0);
      // printf("parser::commitStream - reading top\n");
      std::vector< std::string > savedSections;
      this->commit(s, top_, savedSections, false);
    }

   private:
    void
    dump(std::ostream &s, const Level &l, const std::string &sname);
    void
    parse(Level &l);
    void
    commit(std::ostream &s, Level &l, std::vector< std::string > &savedSections,
           bool disabledSection);
    void
    parseSLine(std::string &sname, size_t &depth);
    void
    err(const char *s);

   private:
    Level top_;
    std::ifstream f0_;
    std::istream *f_;
    std::string line_;
    size_t ln_;
  };

  inline void
  Parser::err(const char *s)
  {
    char buf[256];
    sprintf(buf, "%s on line #%zu", s, ln_);
    throw std::runtime_error(buf);
  }

  inline std::string
  trim(const std::string &s)
  {
    char p[] = " \t\r\n";
    long sp  = 0;
    long ep  = s.length() - 1;
    for(; sp <= ep; ++sp)
      if(!strchr(p, s[sp]))
        break;
    for(; ep >= 0; --ep)
      if(!strchr(p, s[ep]))
        break;
    return s.substr(sp, ep - sp + 1);
  }

  inline Parser::Parser(const char *fn) : f0_(fn), f_(&f0_), ln_(0)
  {
    if(!f0_)
      throw std::runtime_error(std::string("failed to open file: ") + fn);

    parse(top_);
  }

  inline void
  Parser::parseSLine(std::string &sname, size_t &depth)
  {
    depth = 0;
    for(; depth < line_.length(); ++depth)
      if(line_[depth] != '[')
        break;

    sname = line_.substr(depth, line_.length() - 2 * depth);
  }

  inline void
  Parser::parse(Level &l)
  {
    while(std::getline(*f_, line_))
    {
      ++ln_;
      if(line_[0] == '#' || line_[0] == ';')
        continue;
      line_ = trim(line_);
      if(line_.empty())
        continue;
      if(line_[0] == '[')
      {
        size_t depth;
        std::string sname;
        parseSLine(sname, depth);
        Level *lp     = nullptr;
        Level *parent = &l;
        if(depth > l.depth + 1)
          err("section with wrong depth");
        if(l.depth == depth - 1)
          lp = &l.sections[sname];
        else
        {
          lp       = l.parent;
          size_t n = l.depth - depth;
          for(size_t i = 0; i < n; ++i)
            lp = lp->parent;
          parent = lp;
          lp     = &lp->sections[sname];
        }
        if(lp->depth != 0)
          err("duplicate section name on the same level");
        if(!lp->parent)
        {
          lp->depth  = depth;
          lp->parent = parent;
        }
        parent->ordered_sections.push_back(parent->sections.find(sname));
        parse(*lp);
      }
      else
      {
        size_t n = line_.find('=');
        if(n == std::string::npos)
          err("no '=' found");

        auto p =
            std::make_pair(trim(line_.substr(0, n)),
                           trim(line_.substr(n + 1, line_.length() - n - 1)));
        l.values.push_back(p);
      }
    }
  }

  inline void
  saveValues(std::ostream &s, std::vector< std::string > excludes, Level &l)
  {
    // printf("checking keys[%lu] against [%lu]\n", l.values.size(),
    // excludes.size());
    for(auto it = l.values.begin(); it != l.values.end(); ++it)
    {
      // printf("key[%s]\n", it->first.c_str());
      auto check = find(excludes.begin(), excludes.end(), it->first);
      if(check == excludes.end())
      {
        // printf("We didnt write it [%s=%s]\n", it->first.c_str(),
        // it->second.c_str());
        s << it->first + "=" + it->second << "\n";  // commit to stream
      }
    }
  }

  inline void
  Parser::commit(std::ostream &s, Level &l,
                 std::vector< std::string > &savedSections,
                 bool disabledSection)
  {
    std::vector< std::string > keys;
    bool keysChecked = false;
    while(std::getline(*this->f_, line_))
    {
      ++ln_;
      if(line_[0] == '#' || line_[0] == ';')
      {
        s << line_ << "\n";  // commit to stream
        continue;
      }
      std::string tline_ = trim(line_);
      if(tline_.empty())
      {
        s << line_ << "\n";  // commit to stream
        continue;
      }
      if(tline_[0] == '[')
      {
        bool disableNextSection = false;
        size_t depth;
        std::string sname;
        parseSLine(sname, depth);
        s << "[" << sname << "]"
          << "\n";  // commit to stream

        auto test = this->top_.sections.find(sname);
        if(test == this->top_.sections.end())
        {
          // could mean we're done with this section
          // printf("We dont have section [%s]\n", sname.c_str());
          // we'll comment out these keys since we've intentionally dropped them
          disableNextSection = true;
        }

        Level *lp     = NULL;
        Level *parent = &l;
        if(depth > l.depth + 1)
          err("section with wrong depth");

        // if depth is one level deep
        if(l.depth == depth - 1)
        {
          // make level point to one of our sections
          lp = &l.sections[sname];
        }
        else
        {
          // find the parent by depth
          lp       = l.parent;
          size_t n = l.depth - depth;
          for(size_t i = 0; i < n; ++i)
            lp = lp->parent;
          parent = lp;
          lp     = &lp->sections[sname];
        }
        /*
        if(lp->depth != 0)
        {
          printf("has depth still, found [%s] at [%zu]\n", sname.c_str(),
        depth);
        }
        */
        if(!lp->parent)
        {
          printf("no parent\n");
          lp->depth  = depth;
          lp->parent = parent;
        }

        // flush remainder of this section
        saveValues(s, keys, l);
        keysChecked = true;

        // start next section
        this->commit(s, *lp, savedSections, disableNextSection);
        savedSections.push_back(sname);
      }
      else
      {
        size_t n = line_.find('=');
        if(n == std::string::npos)
          err("no '=' found");

        auto key = trim(line_.substr(0, n));
        keys.push_back(key);
        auto val = std::find_if(
            l.values.begin(), l.values.end(),
            [&key](const std::pair< std::string, std::string > &element) {
              return element.first == key;
            });
        if(val != l.values.end())
        {
          if(val->second.c_str()
             == trim(line_.substr(n + 1, line_.length() - n - 1)))
          {
            // copying line
            if(disabledSection)
              s << "# ";
            s << line_ << "\n";  // commit to stream
          }
          else
          {
            // update value
            if(disabledSection)
              s << "# ";
            s << line_.substr(0, n) + "=" + val->second
              << "\n";  // commit to stream
          }
        } /*
         else
         {
           // remove it
           //printf("kv found [%s] no current\n", key.c_str());
         } */
      }
    }

    // handle last section
    if(!keysChecked)
    {
      saveValues(s, keys, l);
    }

    // we're at the main level and have the list of sections
    if(l.sections.size())
    {
      // check to make sure we've written out all the sections we need to
      // printf("sections old[%lu] run[%lu]\n", savedSections.size(),
      // l.sections.size());
      for(auto it = l.sections.begin(); it != l.sections.end(); ++it)
      {
        // printf("sections[%s]\n", it->first.c_str());
        auto check =
            find(savedSections.begin(), savedSections.end(), it->first);
        if(check == savedSections.end())
        {
          // printf("Adding section [%s]\n", it->first.c_str());
          // s << "[" << it->first + "]" << "\n"; // commit to stream
          dump(s, l.sections[it->first], it->first);
        }
      }
    }
  }

  inline void
  Parser::dump(std::ostream &s, const Level &l, const std::string &sname)
  {
    if(!sname.empty())
      s << '\n';
    for(size_t i = 0; i < l.depth; ++i)
      s << '[';
    if(!sname.empty())
      s << sname;
    for(size_t i = 0; i < l.depth; ++i)
      s << ']';
    if(!sname.empty())
      s << std::endl;

    for(const auto &itr : l.values)
      s << itr.first << '=' << itr.second << std::endl;

    for(Level::sections_t::const_iterator it = l.ordered_sections.begin();
        it != l.ordered_sections.end(); ++it)
    {
      assert((*it)->second.depth == l.depth + 1);
      dump(s, (*it)->second, (*it)->first);
    }
  }

}  // namespace ini

#endif  // INI_HPP