#include "pch.h"
#include "utils.h"

namespace Localization {
using Key = uint16_t;

// Maps localization keys to their string identifiers. This is used for text elements to look up the correct localized string.
inline std::unordered_map<std::string, Key> localization_key_map;

using LanguageCode = uint32_t; // 32-bit integer to store the language code (e.g., "en", "fr", "es")

inline LanguageCode current_language = 'e' << 24 | 'n' << 16;

using JoinedKey = uint64_t; // 64-bit integer to store the joined language code and key

inline JoinedKey join_keys(LanguageCode lang_code, Key loc_key) {
  return (static_cast<JoinedKey>(lang_code) << 16) | loc_key;
}

struct Segment {
  bool is_var;
  std::string text;
};

inline std::unordered_map<JoinedKey, std::vector<Segment>> localized_strings;
inline std::unordered_map<std::string, mrb_sym> var_sym_cache;

inline mrb_sym get_var_sym(mrb_state *mrb, const std::string &name) {
  auto it = var_sym_cache.find(name);
  if (it != var_sym_cache.end())
    return it->second;

  mrb_sym sym = mrb_intern_cstr(mrb, name.c_str());
  var_sym_cache[name] = sym;
  return sym;
}

inline std::vector<Segment> parse_localized(const std::string &input) {
  std::vector<Segment> out;

  size_t i = 0;
  while (i < input.size()) {
    size_t start = input.find("%{", i);

    if (start == std::string::npos) {
      out.push_back({false, input.substr(i)});
      break;
    }

    if (start > i) {
      out.push_back({false, input.substr(i, start - i)});
    }

    size_t end = input.find("}", start);
    if (end == std::string::npos) {
      // malformed fallback
      out.push_back({false, input.substr(start)});
      break;
    }

    std::string var = input.substr(start + 2, end - (start + 2));
    out.push_back({true, var});

    i = end + 1;
  }

  return out;
}

inline void set(LanguageCode lang_code, Key key, const std::string &text) {
  localized_strings[join_keys(lang_code, key)] = parse_localized(text);
}

inline std::string get(Key key, const std::unordered_map<std::string, std::string> &params) {
  auto it = localized_strings.find(join_keys(current_language, key));
  if (it == localized_strings.end())
    return "Localization not set!";

  const auto &entry = it->second;

  std::string result;
  result.reserve(10);

  for (const auto &seg : entry) {
    if (!seg.is_var) {
      result += seg.text;
    } else {
      auto param_it = params.find(seg.text);
      if (param_it == params.end()) {
        result += "%{" + seg.text + "}";
        continue;
      }
      result += param_it->second;
    }
  }

  return result;
}

inline LanguageCode lang_from_sym(mrb_state *mrb, mrb_sym sym) {
  const char *s = mrb_sym2name(mrb, sym);
  size_t len = strlen(s);

  if (len == 0 || len > 4)
    return 0;

  LanguageCode code = 0;

  for (size_t i = 0; i < len; ++i) {
    code |= (static_cast<LanguageCode>(s[i]) << (8 * (3 - i)));
  }

  return code;
}

inline mrb_sym lang_to_sym(mrb_state *mrb, LanguageCode code) {
  char s[5] = {0};
  for (int i = 0; i < 4; ++i)
    s[i] = (code >> (8 * (3 - i))) & 0xFF;
  return mrb_intern_cstr(mrb, s);
}

inline Key key_from_sym(mrb_state *mrb, mrb_sym sym) {
  const char *key_name = mrb_sym2name(mrb, sym);

  auto it = localization_key_map.find(key_name);
  if (it != localization_key_map.end())
    return it->second;

  Key new_id = (Key)localization_key_map.size();
  localization_key_map[key_name] = new_id;
  return new_id;
}

// This is only used for debugging and inspect output, so performance is not a concern
inline std::string get_key_name(Key key) {
  for (const auto &[str, k] : localization_key_map)
    if (k == key)
      return str;
  return "Unknown Key";
}
} // namespace Localization