#include "game/entities/entity_writer.hpp"

#ifdef _DEBUG

#include <cstddef>
#include <filesystem>
#include <fstream>
#include <sstream>
#include <string>
#include <system_error>

namespace EntityWriter {

    namespace {

        // Cerca la línia que comença per `<key>:` a columna 0. Mateix
        // patró que TilemapWriter::findDataLine però parametritzat. Si
        // un dia paga la pena, podem extreure'l a un helper compartit.
        auto findKeyLine(const std::string& content, const std::string& key) -> std::size_t {
            const std::string PREFIX = key + ":";
            std::size_t pos = 0;
            while (pos < content.size()) {
                const bool AT_LINE_START = (pos == 0 || content[pos - 1] == '\n');
                if (AT_LINE_START && content.compare(pos, PREFIX.size(), PREFIX) == 0) {
                    const std::size_t AFTER = pos + PREFIX.size();
                    if (AFTER >= content.size() || content[AFTER] == '\n' || content[AFTER] == '\r' || content[AFTER] == ' ' || content[AFTER] == '\t' || content[AFTER] == '#') {
                        return pos;
                    }
                }
                const auto NL = content.find('\n', pos);
                if (NL == std::string::npos) { break; }
                pos = NL + 1;
            }
            return std::string::npos;
        }

        // Avança mentre trobe línies indentades (espai/tab) o línies buides.
        // A diferència del TilemapWriter, ací incloem línies buides dins
        // del bloc: l'editor de YAML deixa sovint blanc entre grups
        // d'entitats, i volem absorbir-lo per no deixar restes orfes
        // entre el bloc nou i el següent top-level.
        auto advancePastBlock(const std::string& content, std::size_t pos) -> std::size_t {
            while (pos < content.size()) {
                const char C = content[pos];
                const bool IS_INDENT = (C == ' ' || C == '\t');
                const bool IS_BLANK = (C == '\n' || C == '\r');
                if (!IS_INDENT && !IS_BLANK) { break; }
                const auto NL = content.find('\n', pos);
                pos = (NL == std::string::npos) ? content.size() : NL + 1;
            }
            return pos;
        }

        auto buildBlock(const std::vector<Spawn>& spawns) -> std::string {
            std::string out;
            for (const auto& s : spawns) {
                out += "  - type: " + s.type + "\n";
                if (s.sarc_col.has_value() && s.sarc_row.has_value()) {
                    out += "    sarc_position: [" + std::to_string(*s.sarc_col) + ", " + std::to_string(*s.sarc_row) + "]\n";
                } else if (s.col.has_value() && s.row.has_value()) {
                    out += "    position: [" + std::to_string(*s.col) + ", " + std::to_string(*s.row) + "]\n";
                }
            }
            return out;
        }

    }  // namespace

    auto saveEntitiesBlock(const std::string& path, const std::vector<Spawn>& spawns) -> bool {
        std::ifstream in(path, std::ios::binary);
        if (!in) { return false; }
        std::ostringstream ss;
        ss << in.rdbuf();
        const std::string CONTENT = ss.str();
        in.close();

        const auto KEY_POS = findKeyLine(CONTENT, "entities");
        if (KEY_POS == std::string::npos) { return false; }

        const auto LINE_END = CONTENT.find('\n', KEY_POS);
        const auto AFTER_KEY = (LINE_END == std::string::npos) ? CONTENT.size() : LINE_END + 1;
        const auto BLOCK_END = advancePastBlock(CONTENT, AFTER_KEY);

        // Mantenim una línia en blanc darrere del bloc si abans n'hi
        // havia: ajuda a separar visualment el `entities:` de la pròxima
        // secció. Si no n'hi havia, no afegim res.
        const std::string TAIL = CONTENT.substr(BLOCK_END);
        const std::string NEW_CONTENT =
            CONTENT.substr(0, AFTER_KEY) + buildBlock(spawns) + TAIL;

        const auto TMP_PATH = path + ".tmp";
        {
            std::ofstream out(TMP_PATH, std::ios::binary | std::ios::trunc);
            if (!out) { return false; }
            out.write(NEW_CONTENT.data(), static_cast<std::streamsize>(NEW_CONTENT.size()));
            out.close();
            if (!out) {
                std::error_code ec;
                std::filesystem::remove(TMP_PATH, ec);
                return false;
            }
        }

        std::error_code ec;
        std::filesystem::rename(TMP_PATH, path, ec);
        if (ec) {
            std::filesystem::remove(TMP_PATH, ec);
            return false;
        }
        return true;
    }

}  // namespace EntityWriter

#endif  // _DEBUG