import baseLogger from './logger.js';
import EventEmitter from './EventEmitter.js';
import postProcessor from './postProcessor.js';
import { copy as utilsCopy, looksLikeObjectPath, isString } from './utils.js';
import keysFromSelector from './selector.js';

const shouldHandleAsObject = (res) =>
  !isString(res) && typeof res !== 'boolean' && typeof res !== 'number';

class Translator extends EventEmitter {
  constructor(services, options = {}) {
    super();

    utilsCopy(
      [
        'resourceStore',
        'languageUtils',
        'pluralResolver',
        'interpolator',
        'backendConnector',
        'i18nFormat',
        'utils',
      ],
      services,
      this,
    );

    this.options = options;
    if (this.options.keySeparator === undefined) {
      this.options.keySeparator = '.';
    }

    this.logger = baseLogger.create('translator');

    this.checkedLoadedFor = {};
  }

  changeLanguage(lng) {
    if (lng) this.language = lng;
  }

  exists(key, o = { interpolation: {} }) {
    const opt = { ...o };
    if (key == null) return false;
    const resolved = this.resolve(key, opt);

    // If no resource found, return false
    if (resolved?.res === undefined) return false;

    // Check if the resolved resource is an object
    const isObject = shouldHandleAsObject(resolved.res);

    // If returnObjects is explicitly set to false and the resource is an object, return false
    if (opt.returnObjects === false && isObject) {
      return false;
    }

    // Otherwise return true (resource exists)
    return true;
  }

  extractFromKey(key, opt) {
    let nsSeparator = opt.nsSeparator !== undefined ? opt.nsSeparator : this.options.nsSeparator;
    if (nsSeparator === undefined) nsSeparator = ':';

    const keySeparator =
      opt.keySeparator !== undefined ? opt.keySeparator : this.options.keySeparator;

    let namespaces = opt.ns || this.options.defaultNS || [];
    const wouldCheckForNsInKey = nsSeparator && key.includes(nsSeparator);
    const seemsNaturalLanguage =
      !this.options.userDefinedKeySeparator &&
      !opt.keySeparator &&
      !this.options.userDefinedNsSeparator &&
      !opt.nsSeparator &&
      !looksLikeObjectPath(key, nsSeparator, keySeparator);
    if (wouldCheckForNsInKey && !seemsNaturalLanguage) {
      const m = key.match(this.interpolator.nestingRegexp);
      if (m && m.length > 0) {
        return {
          key,
          namespaces: isString(namespaces) ? [namespaces] : namespaces,
        };
      }
      const parts = key.split(nsSeparator);
      if (
        nsSeparator !== keySeparator ||
        (nsSeparator === keySeparator && this.options.ns.includes(parts[0]))
      )
        namespaces = parts.shift();
      key = parts.join(keySeparator);
    }

    return {
      key,
      namespaces: isString(namespaces) ? [namespaces] : namespaces,
    };
  }

  translate(keys, o, lastKey) {
    let opt = typeof o === 'object' ? { ...o } : o;
    if (typeof opt !== 'object' && this.options.overloadTranslationOptionHandler) {
      opt = this.options.overloadTranslationOptionHandler(arguments);
    }
    if (typeof opt === 'object') opt = { ...opt };
    if (!opt) opt = {};

    // non valid keys handling
    if (keys == null /* || keys === '' */) return '';
    if (typeof keys === 'function') keys = keysFromSelector(keys, { ...this.options, ...opt });
    if (!Array.isArray(keys)) keys = [String(keys)];
    keys = keys.map((k) =>
      typeof k === 'function' ? keysFromSelector(k, { ...this.options, ...opt }) : String(k),
    );

    const returnDetails =
      opt.returnDetails !== undefined ? opt.returnDetails : this.options.returnDetails;

    // separators
    const keySeparator =
      opt.keySeparator !== undefined ? opt.keySeparator : this.options.keySeparator;

    // get namespace(s)
    const { key, namespaces } = this.extractFromKey(keys[keys.length - 1], opt);
    const namespace = namespaces[namespaces.length - 1];

    let nsSeparator = opt.nsSeparator !== undefined ? opt.nsSeparator : this.options.nsSeparator;
    if (nsSeparator === undefined) nsSeparator = ':';

    // return key on CIMode
    const lng = opt.lng || this.language;
    const appendNamespaceToCIMode =
      opt.appendNamespaceToCIMode || this.options.appendNamespaceToCIMode;
    if (lng?.toLowerCase() === 'cimode') {
      if (appendNamespaceToCIMode) {
        if (returnDetails) {
          return {
            res: `${namespace}${nsSeparator}${key}`,
            usedKey: key,
            exactUsedKey: key,
            usedLng: lng,
            usedNS: namespace,
            usedParams: this.getUsedParamsDetails(opt),
          };
        }
        return `${namespace}${nsSeparator}${key}`;
      }

      if (returnDetails) {
        return {
          res: key,
          usedKey: key,
          exactUsedKey: key,
          usedLng: lng,
          usedNS: namespace,
          usedParams: this.getUsedParamsDetails(opt),
        };
      }
      return key;
    }

    // resolve from store
    const resolved = this.resolve(keys, opt);
    let res = resolved?.res;
    const resUsedKey = resolved?.usedKey || key;
    const resExactUsedKey = resolved?.exactUsedKey || key;

    const noObject = ['[object Number]', '[object Function]', '[object RegExp]'];
    const joinArrays = opt.joinArrays !== undefined ? opt.joinArrays : this.options.joinArrays;

    // object
    const handleAsObjectInI18nFormat = !this.i18nFormat || this.i18nFormat.handleAsObject;
    const needsPluralHandling = opt.count !== undefined && !isString(opt.count);
    const hasDefaultValue = Translator.hasDefaultValue(opt);
    const defaultValueSuffix = needsPluralHandling
      ? this.pluralResolver.getSuffix(lng, opt.count, opt)
      : '';
    const defaultValueSuffixOrdinalFallback =
      opt.ordinal && needsPluralHandling
        ? this.pluralResolver.getSuffix(lng, opt.count, { ordinal: false })
        : '';
    const needsZeroSuffixLookup = needsPluralHandling && !opt.ordinal && opt.count === 0;
    const defaultValue =
      (needsZeroSuffixLookup && opt[`defaultValue${this.options.pluralSeparator}zero`]) ||
      opt[`defaultValue${defaultValueSuffix}`] ||
      opt[`defaultValue${defaultValueSuffixOrdinalFallback}`] ||
      opt.defaultValue;

    let resForObjHndl = res;
    if (handleAsObjectInI18nFormat && !res && hasDefaultValue) {
      resForObjHndl = defaultValue;
    }

    const handleAsObject = shouldHandleAsObject(resForObjHndl);
    const resType = Object.prototype.toString.apply(resForObjHndl);

    if (
      handleAsObjectInI18nFormat &&
      resForObjHndl &&
      handleAsObject &&
      !noObject.includes(resType) &&
      !(isString(joinArrays) && Array.isArray(resForObjHndl))
    ) {
      if (!opt.returnObjects && !this.options.returnObjects) {
        if (!this.options.returnedObjectHandler) {
          this.logger.warn('accessing an object - but returnObjects options is not enabled!');
        }
        const r = this.options.returnedObjectHandler
          ? this.options.returnedObjectHandler(resUsedKey, resForObjHndl, {
              ...opt,
              ns: namespaces,
            })
          : `key '${key} (${this.language})' returned an object instead of string.`;
        if (returnDetails) {
          resolved.res = r;
          resolved.usedParams = this.getUsedParamsDetails(opt);
          return resolved;
        }
        return r;
      }

      // if we got a separator we loop over children - else we just return object as is
      // as having it set to false means no hierarchy so no lookup for nested values
      if (keySeparator) {
        const resTypeIsArray = Array.isArray(resForObjHndl);
        const copy = resTypeIsArray ? [] : {}; // apply child translation on a copy

        const newKeyToUse = resTypeIsArray ? resExactUsedKey : resUsedKey;
        for (const m in resForObjHndl) {
          if (Object.prototype.hasOwnProperty.call(resForObjHndl, m)) {
            const deepKey = `${newKeyToUse}${keySeparator}${m}`;
            if (hasDefaultValue && !res) {
              copy[m] = this.translate(deepKey, {
                ...opt,
                defaultValue: shouldHandleAsObject(defaultValue) ? defaultValue[m] : undefined,
                ...{ joinArrays: false, ns: namespaces },
              });
            } else {
              copy[m] = this.translate(deepKey, {
                ...opt,
                ...{ joinArrays: false, ns: namespaces },
              });
            }
            if (copy[m] === deepKey) copy[m] = resForObjHndl[m]; // if nothing found use original value as fallback
          }
        }
        res = copy;
      }
    } else if (handleAsObjectInI18nFormat && isString(joinArrays) && Array.isArray(res)) {
      // array special treatment
      res = res.join(joinArrays);
      if (res) res = this.extendTranslation(res, keys, opt, lastKey);
    } else {
      // string, empty or null
      let usedDefault = false;
      let usedKey = false;

      // fallback value
      if (!this.isValidLookup(res) && hasDefaultValue) {
        usedDefault = true;
        res = defaultValue;
      }
      if (!this.isValidLookup(res)) {
        usedKey = true;
        res = key;
      }

      const missingKeyNoValueFallbackToKey =
        opt.missingKeyNoValueFallbackToKey || this.options.missingKeyNoValueFallbackToKey;
      const resForMissing = missingKeyNoValueFallbackToKey && usedKey ? undefined : res;

      // save missing
      const updateMissing = hasDefaultValue && defaultValue !== res && this.options.updateMissing;
      if (usedKey || usedDefault || updateMissing) {
        this.logger.log(
          updateMissing ? 'updateKey' : 'missingKey',
          lng,
          namespace,
          needsPluralHandling && !updateMissing
            ? `${key}${this.pluralResolver.getSuffix(lng, opt.count, opt)}`
            : key,
          updateMissing ? defaultValue : res,
        );
        if (keySeparator) {
          const fk = this.resolve(key, { ...opt, keySeparator: false });
          if (fk && fk.res)
            this.logger.warn(
              'Seems the loaded translations were in flat JSON format instead of nested. Either set keySeparator: false on init or make sure your translations are published in nested format.',
            );
        }

        let lngs = [];
        const fallbackLngs = this.languageUtils.getFallbackCodes(
          this.options.fallbackLng,
          opt.lng || this.language,
        );
        if (this.options.saveMissingTo === 'fallback' && fallbackLngs && fallbackLngs[0]) {
          for (let i = 0; i < fallbackLngs.length; i++) {
            lngs.push(fallbackLngs[i]);
          }
        } else if (this.options.saveMissingTo === 'all') {
          lngs = this.languageUtils.toResolveHierarchy(opt.lng || this.language);
        } else {
          lngs.push(opt.lng || this.language);
        }

        const send = (l, k, specificDefaultValue) => {
          const defaultForMissing =
            hasDefaultValue && specificDefaultValue !== res ? specificDefaultValue : resForMissing;
          if (this.options.missingKeyHandler) {
            this.options.missingKeyHandler(l, namespace, k, defaultForMissing, updateMissing, opt);
          } else if (this.backendConnector?.saveMissing) {
            this.backendConnector.saveMissing(
              l,
              namespace,
              k,
              defaultForMissing,
              updateMissing,
              opt,
            );
          }
          this.emit('missingKey', l, namespace, k, res);
        };

        if (this.options.saveMissing) {
          if (this.options.saveMissingPlurals && needsPluralHandling) {
            lngs.forEach((language) => {
              const suffixes = this.pluralResolver.getSuffixes(language, opt);
              if (
                needsZeroSuffixLookup &&
                opt[`defaultValue${this.options.pluralSeparator}zero`] &&
                !suffixes.includes(`${this.options.pluralSeparator}zero`)
              ) {
                suffixes.push(`${this.options.pluralSeparator}zero`);
              }
              suffixes.forEach((suffix) => {
                send([language], key + suffix, opt[`defaultValue${suffix}`] || defaultValue);
              });
            });
          } else {
            send(lngs, key, defaultValue);
          }
        }
      }

      // extend
      res = this.extendTranslation(res, keys, opt, resolved, lastKey);

      // append namespace if still key
      if (usedKey && res === key && this.options.appendNamespaceToMissingKey) {
        res = `${namespace}${nsSeparator}${key}`;
      }

      // parseMissingKeyHandler
      if ((usedKey || usedDefault) && this.options.parseMissingKeyHandler) {
        res = this.options.parseMissingKeyHandler(
          this.options.appendNamespaceToMissingKey ? `${namespace}${nsSeparator}${key}` : key,
          usedDefault ? res : undefined,
          opt,
        );
      }
    }

    // return
    if (returnDetails) {
      resolved.res = res;
      resolved.usedParams = this.getUsedParamsDetails(opt);
      return resolved;
    }
    return res;
  }

  extendTranslation(res, key, opt, resolved, lastKey) {
    if (this.i18nFormat?.parse) {
      res = this.i18nFormat.parse(
        res,
        { ...this.options.interpolation.defaultVariables, ...opt },
        opt.lng || this.language || resolved.usedLng,
        resolved.usedNS,
        resolved.usedKey,
        { resolved },
      );
    } else if (!opt.skipInterpolation) {
      // i18next.parsing
      if (opt.interpolation)
        this.interpolator.init({
          ...opt,
          ...{ interpolation: { ...this.options.interpolation, ...opt.interpolation } },
        });
      const skipOnVariables =
        isString(res) &&
        (opt?.interpolation?.skipOnVariables !== undefined
          ? opt.interpolation.skipOnVariables
          : this.options.interpolation.skipOnVariables);
      let nestBef;
      if (skipOnVariables) {
        const nb = res.match(this.interpolator.nestingRegexp);
        // has nesting aftbeforeer interpolation
        nestBef = nb && nb.length;
      }

      // interpolate
      let data = opt.replace && !isString(opt.replace) ? opt.replace : opt;
      if (this.options.interpolation.defaultVariables)
        data = { ...this.options.interpolation.defaultVariables, ...data };
      res = this.interpolator.interpolate(
        res,
        data,
        opt.lng || this.language || resolved.usedLng,
        opt,
      );

      // nesting
      if (skipOnVariables) {
        const na = res.match(this.interpolator.nestingRegexp);
        // has nesting after interpolation
        const nestAft = na && na.length;
        if (nestBef < nestAft) opt.nest = false;
      }
      if (!opt.lng && resolved && resolved.res) opt.lng = this.language || resolved.usedLng;
      if (opt.nest !== false)
        res = this.interpolator.nest(
          res,
          (...args) => {
            if (lastKey?.[0] === args[0] && !opt.context) {
              this.logger.warn(
                `It seems you are nesting recursively key: ${args[0]} in key: ${key[0]}`,
              );
              return null;
            }
            return this.translate(...args, key);
          },
          opt,
        );

      if (opt.interpolation) this.interpolator.reset();
    }

    // post process
    const postProcess = opt.postProcess || this.options.postProcess;
    const postProcessorNames = isString(postProcess) ? [postProcess] : postProcess;

    if (res != null && postProcessorNames?.length && opt.applyPostProcessor !== false) {
      res = postProcessor.handle(
        postProcessorNames,
        res,
        key,
        this.options && this.options.postProcessPassResolved
          ? {
              i18nResolved: { ...resolved, usedParams: this.getUsedParamsDetails(opt) },
              ...opt,
            }
          : opt,
        this,
      );
    }

    return res;
  }

  resolve(keys, opt = {}) {
    let found;
    let usedKey; // plain key
    let exactUsedKey; // key with context / plural
    let usedLng;
    let usedNS;

    if (isString(keys)) keys = [keys];
    if (Array.isArray(keys))
      keys = keys.map((k) =>
        typeof k === 'function' ? keysFromSelector(k, { ...this.options, ...opt }) : k,
      );

    // forEach possible key
    keys.forEach((k) => {
      if (this.isValidLookup(found)) return;
      const extracted = this.extractFromKey(k, opt);
      const key = extracted.key;
      usedKey = key;
      let namespaces = extracted.namespaces;
      if (this.options.fallbackNS) namespaces = namespaces.concat(this.options.fallbackNS);

      const needsPluralHandling = opt.count !== undefined && !isString(opt.count);
      const needsZeroSuffixLookup = needsPluralHandling && !opt.ordinal && opt.count === 0;
      const needsContextHandling =
        opt.context !== undefined &&
        (isString(opt.context) || typeof opt.context === 'number') &&
        opt.context !== '';

      const codes = opt.lngs
        ? opt.lngs
        : this.languageUtils.toResolveHierarchy(opt.lng || this.language, opt.fallbackLng);

      namespaces.forEach((ns) => {
        if (this.isValidLookup(found)) return;
        usedNS = ns;

        if (
          !this.checkedLoadedFor[`${codes[0]}-${ns}`] &&
          this.utils?.hasLoadedNamespace &&
          !this.utils?.hasLoadedNamespace(usedNS)
        ) {
          this.checkedLoadedFor[`${codes[0]}-${ns}`] = true;
          this.logger.warn(
            `key "${usedKey}" for languages "${codes.join(
              ', ',
            )}" won't get resolved as namespace "${usedNS}" was not yet loaded`,
            'This means something IS WRONG in your setup. You access the t function before i18next.init / i18next.loadNamespace / i18next.changeLanguage was done. Wait for the callback or Promise to resolve before accessing it!!!',
          );
        }

        codes.forEach((code) => {
          if (this.isValidLookup(found)) return;
          usedLng = code;

          const finalKeys = [key];

          if (this.i18nFormat?.addLookupKeys) {
            this.i18nFormat.addLookupKeys(finalKeys, key, code, ns, opt);
          } else {
            let pluralSuffix;
            if (needsPluralHandling)
              pluralSuffix = this.pluralResolver.getSuffix(code, opt.count, opt);
            const zeroSuffix = `${this.options.pluralSeparator}zero`;
            const ordinalPrefix = `${this.options.pluralSeparator}ordinal${this.options.pluralSeparator}`;
            // get key for plural if needed
            if (needsPluralHandling) {
              if (opt.ordinal && pluralSuffix.startsWith(ordinalPrefix)) {
                finalKeys.push(
                  key + pluralSuffix.replace(ordinalPrefix, this.options.pluralSeparator),
                );
              }
              finalKeys.push(key + pluralSuffix);
              if (needsZeroSuffixLookup) {
                finalKeys.push(key + zeroSuffix);
              }
            }

            // get key for context if needed
            if (needsContextHandling) {
              const contextKey = `${key}${this.options.contextSeparator || '_'}${opt.context}`;
              finalKeys.push(contextKey);

              // get key for context + plural if needed
              if (needsPluralHandling) {
                if (opt.ordinal && pluralSuffix.startsWith(ordinalPrefix)) {
                  finalKeys.push(
                    contextKey + pluralSuffix.replace(ordinalPrefix, this.options.pluralSeparator),
                  );
                }
                finalKeys.push(contextKey + pluralSuffix);
                if (needsZeroSuffixLookup) {
                  finalKeys.push(contextKey + zeroSuffix);
                }
              }
            }
          }

          // iterate over finalKeys starting with most specific pluralkey (-> contextkey only) -> singularkey only
          let possibleKey;
          while ((possibleKey = finalKeys.pop())) {
            if (!this.isValidLookup(found)) {
              exactUsedKey = possibleKey;
              found = this.getResource(code, ns, possibleKey, opt);
            }
          }
        });
      });
    });

    return { res: found, usedKey, exactUsedKey, usedLng, usedNS };
  }

  isValidLookup(res) {
    return (
      res !== undefined &&
      !(!this.options.returnNull && res === null) &&
      !(!this.options.returnEmptyString && res === '')
    );
  }

  getResource(code, ns, key, options = {}) {
    if (this.i18nFormat?.getResource) return this.i18nFormat.getResource(code, ns, key, options);
    return this.resourceStore.getResource(code, ns, key, options);
  }

  getUsedParamsDetails(options = {}) {
    // we need to remember to extend this array whenever new option properties are added
    const optionsKeys = [
      'defaultValue',
      'ordinal',
      'context',
      'replace',
      'lng',
      'lngs',
      'fallbackLng',
      'ns',
      'keySeparator',
      'nsSeparator',
      'returnObjects',
      'returnDetails',
      'joinArrays',
      'postProcess',
      'interpolation',
    ];

    const useOptionsReplaceForData = options.replace && !isString(options.replace);
    let data = useOptionsReplaceForData ? options.replace : options;
    if (useOptionsReplaceForData && typeof options.count !== 'undefined') {
      data = { ...data, count: options.count };
    }

    if (this.options.interpolation.defaultVariables) {
      data = { ...this.options.interpolation.defaultVariables, ...data };
    }

    // avoid reporting options (execpt count) as usedParams
    if (!useOptionsReplaceForData) {
      data = { ...data };
      for (const key of optionsKeys) {
        delete data[key];
      }
    }

    return data;
  }

  static hasDefaultValue(options) {
    const prefix = 'defaultValue';

    for (const option in options) {
      if (
        Object.prototype.hasOwnProperty.call(options, option) &&
        option.startsWith(prefix) &&
        undefined !== options[option]
      ) {
        return true;
      }
    }

    return false;
  }
}

export default Translator;