/*
 * (C) Copyright 2013 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 * In applying this licence, ECMWF does not waive the privileges and immunities
 * granted to it by virtue of its status as an intergovernmental organisation
 * nor does it submit to any jurisdiction.
 */

// file deepcode ignore CppMemoryLeak: static pointers for global registry are OK and will be cleaned up at end

#include "GridBuilder.h"

#include <regex.h>
#include <iomanip>

#include "eckit/thread/AutoLock.h"
#include "eckit/thread/Mutex.h"
#include "eckit/utils/Translator.h"

#include "atlas/grid/detail/grid/GridFactory.h"
#include "atlas/runtime/Exception.h"
#include "atlas/runtime/Log.h"
#include "atlas/util/Config.h"

namespace atlas {
namespace grid {

namespace {

size_t regex_count_parens(const std::string& string) {
    size_t out              = 0;
    bool last_was_backslash = 0;
    for (const char* step = string.c_str(); *step != '\0'; step++) {
        if (*step == '\\' && !last_was_backslash) {
            last_was_backslash = true;
            continue;
        }
        if (*step == ')' && !last_was_backslash) {
            out++;
        }
        last_was_backslash = false;
    }
    return out;
}

int regex_match_impl(const std::string& string, const std::string& regex, std::vector<std::string>& substr,
                     bool use_substr, bool use_case) {
    regex_t re;
    size_t matchcount = 0;
    if (use_substr) {
        matchcount = regex_count_parens(regex);
    }
    std::vector<regmatch_t> result(matchcount + 1);
    int compiled_ok =
        !regcomp(&re, regex.c_str(), REG_EXTENDED + (use_case ? 0 : REG_ICASE) + (use_substr ? 0 : REG_NOSUB));

    if (!compiled_ok) {
        Log::error() << "This regular expression didn't compile: \"" << regex << "\"" << std::endl;
    }

    ATLAS_ASSERT(compiled_ok);

    int found = !regexec(&re, string.c_str(), matchcount + 1, result.data(), 0);
    if (found && use_substr) {
        substr.resize(matchcount);
        // match zero is the whole string; ignore it.
        for (size_t i = 0; i < matchcount; i++) {
            if (result[i + 1].rm_eo > 0) {
                // GNU peculiarity: match-to-empty marked with -1.
                size_t length_of_match = result[i + 1].rm_eo - result[i + 1].rm_so;
                substr[i]              = std::string(&string[result[i + 1].rm_so], length_of_match);
            }
        }
    }
    regfree(&re);
    return found;
}

class Regex {
public:
    Regex(const std::string& regex, bool use_case = true): regex_(regex), use_case_(use_case) {}
    /*
    // unused
    bool match( const std::string& string ) const {
        std::vector<std::string> substr;
        return regex_match_impl( string, regex_, substr, false, use_case_ );
    }
*/
    bool match(const std::string& string, std::vector<std::string>& substr) const {
        return regex_match_impl(string, regex_, substr, true, use_case_);
    }

    /*
    // unused
    operator std::string() const { return regex_; }
*/

private:
    std::string regex_;
    bool use_case_;
};

static eckit::Mutex* local_mutex          = nullptr;
static GridBuilder::Registry* named_grids = nullptr;
static GridBuilder::Registry* typed_grids = nullptr;

static pthread_once_t once = PTHREAD_ONCE_INIT;

static void init() {
    local_mutex = new eckit::Mutex();
    named_grids = new GridBuilder::Registry();
    typed_grids = new GridBuilder::Registry();
}

}  // anonymous namespace

//---------------------------------------------------------------------------------------------------------------------

namespace detail {
namespace grid {
void force_link_CubedSphere();
void force_link_CubedSphere2();
void force_link_Gaussian();
void force_link_LonLat();
void force_link_Regional();
void force_link_Regional_var_resolution();
}  // namespace grid
}  // namespace detail

const GridBuilder::Registry& GridBuilder::nameRegistry() {
    detail::grid::force_link_CubedSphere();
    detail::grid::force_link_CubedSphere2();
    detail::grid::force_link_Gaussian();
    detail::grid::force_link_LonLat();
    detail::grid::force_link_Regional();
    detail::grid::force_link_Regional_var_resolution();
    return *named_grids;
}

const GridBuilder::Registry& GridBuilder::typeRegistry() {
    return *typed_grids;
}

GridBuilder::GridBuilder(const std::string& type): names_(), type_(type) {
    pthread_once(&once, init);
    eckit::AutoLock<eckit::Mutex> lock(local_mutex);

    ATLAS_ASSERT(typed_grids->find(type_) == typed_grids->end());
    (*typed_grids)[type] = this;
}

GridBuilder::GridBuilder(const std::string& type, const std::vector<std::string>& regexes,
                         const std::vector<std::string>& names):
    names_(regexes), pretty_names_(names), type_(type) {
    pthread_once(&once, init);
    eckit::AutoLock<eckit::Mutex> lock(local_mutex);

    for (const std::string& name : names_) {
        ATLAS_ASSERT(named_grids->find(name) == named_grids->end());
        (*named_grids)[name] = this;
    }

    ATLAS_ASSERT(typed_grids->find(type_) == typed_grids->end());
    (*typed_grids)[type] = this;
}

GridBuilder::~GridBuilder() {
    pthread_once(&once, init);
    eckit::AutoLock<eckit::Mutex> lock(local_mutex);

    for (const std::string& name : names_) {
        ATLAS_ASSERT(named_grids->find(name) != named_grids->end());
        (*named_grids).erase(name);
    }

    if (not type_.empty()) {
        ATLAS_ASSERT(typed_grids->find(type_) != typed_grids->end());
        (*typed_grids).erase(type_);
    }
}

void GridBuilder::registerNamedGrid(const std::string& name) {
    pthread_once(&once, init);
    eckit::AutoLock<eckit::Mutex> lock(local_mutex);
    std::string regex = "^"+name+"$";
    ATLAS_ASSERT(named_grids->find(regex) == named_grids->end());
    (*named_grids)[regex] = this;
    names_.emplace_back(regex);
    pretty_names_.emplace_back(name);
}

const Grid::Implementation* GridBuilder::create(const Grid::Config& config) const {
    //eckit::Factory<Grid::Implementation>& fact = eckit::Factory<Grid::Implementation>::instance();

    std::string name;
    if (config.get("name", name)) {  // ignore any further configuration
        return create(name);
    }

    std::string type;
    if (config.get("type", type) && GridFactory::has(type)) {
        return GridFactory::build(type, config);
    }

    if (name.size()) {
        Log::error() << "name provided: " << name << std::endl;
    }
    if (type.size()) {
        Log::error() << "type provided: " << type << std::endl;
    }
    if (name.empty() && type.empty()) {
        throw_Exception("no name or type in configuration", Here());
    }
    else {
        throw_Exception("name or type in configuration don't exist", Here());
    }
}

bool GridBuilder::match(const std::string& string, std::vector<std::string>& matches, int& id) const {
    id = 0;
    for (const std::string& name : names_) {
        if (Regex(name).match(string, matches)) {
            return true;
        }
        ++id;
    }
    return false;
}

const std::string& GridBuilder::type() const {
    return type_;
}

const std::vector<std::string>& GridBuilder::names() const {
    return pretty_names_;
}

const std::vector<std::string>& GridBuilder::regexes() const {
    return names_;
}

std::ostream& operator<<(std::ostream& os, const GridBuilder& g) {
    g.print(os);
    return os;
}

//---------------------------------------------------------------------------------------------------------------------

}  // namespace grid
}  // namespace atlas
