const verbsHelper = require('english-verbs-helper');
const verbsIrregular = require('english-verbs-irregular/dist/verbs.json');
const verbsGerunds = require('english-verbs-gerunds/dist/gerunds.json');
const verbsData = verbsHelper.mergeVerbsData(verbsIrregular, verbsGerunds);

/* Replaces verbs, point-of-view, name, pronouns, and "also" terms */
function replaceAll() {
  browser.storage.local.get(null, (options) => {
    const hostname = window.location.hostname;
    const isEnabled = !(options.domains === undefined) && options.domains.includes(hostname);
    if (!isEnabled) { return; }

    const isNameSet = !(options.name === undefined || options.name == "");
    const isPronounsSet = !(options.preset === undefined || options.preset == "");
    const isPovSet = !(options.pov === undefined || options.pov == "");
    const isPovLegal = isPovSet && (options.pov != "third" || (isNameSet && isPronounsSet));

    if (isPovLegal) {
      replaceVerbs(options);
      replacePov(options);
      replacePlv(options);
    }

    if (isNameSet) {
      replaceName(options);
    }

    if (isPronounsSet) {
      replacePronouns(options);
    }

    const isAlsoSet = !options.also === undefined;
    if (isAlsoSet) {
      replaceAlso(options);
    }
  });
}

/* Replaces all instances of "Y/n" with the user's name */
function replaceName(options) {
  const searchTerm = /\by\/n\b|\(y\/n\)|\[y\/n\]/ig;
  walk(document.body, searchTerm, options["name"], directMethod);
}

/* Replaces all verb keys */
function replaceVerbs(options) {
  const isPlural = getPronouns(options.preset, options.other).plurality == "plural";
  if (isPlural) {
    walk(document.body, /([Vv])r([Nn])\/([\w\s]+)\/([\w\s]+)\//, options, pluralPrnVerbMethod);
  } else {
    walk(document.body, /([Vv])r[Nn]\/([\w\s]+)\/([\w\s]+)\//, options, prnVerbMethod);
  }

  const isPluralThird = isPlural && options.pov == "third";
  if (isPluralThird) {
    walk(document.body, /([Vv])r([Bb])\/([\w\s]+)\/([\w\s]+)\//, options, pluralThirdVerbMethod);
  } else {
    walk(document.body, /([Vv])r[Bb]\/([\w\s]+)\/([\w\s]+)\//, options, verbMethod);
  }
}

/* Replaces all pronoun keys */
/* This could be made faster if I give premade regexp expressions for each, but I don't want to do that! */
function replacePronouns(options) {
  let pronouns = getPronouns(options.preset, options.other);
  replacePronounSet("Prn/s", "prn/s", pronouns["subjective"]);
  replacePronounSet("Prn/o", "prn/o", pronouns["objective"]);
  replacePronounSet("Prn/p", "prn/p", pronouns["possessive"]);
  replacePronounSet("Prn/a", "prn/a", pronouns["adjective"]);
  replacePronounSet("Prn/r", "prn/r", pronouns["reflexive"]);
  replacePronounSet("Prn/H", "prn/H", pronouns["honorific-abbr"]);
  replacePronounSet("Prn/h", "prn/h", pronouns["honorific"]);
  replacePronounSet("Prn/N", "prn/N", pronouns["adult"]);
  replacePronounSet("Prn/n", "prn/n", pronouns["youth"]);
  replacePronounSet("Prn/F", "prn/f", pronouns["parent"]);
  replacePronounSet("Prn/f", "prn/f", pronouns["child"]);
  replacePronounSet("Prn/k", "prn/k", pronouns["sibling"]);
  replacePronounSet("Prn/m", "prn/m", pronouns["married"]);
  replacePronounSet("Prn/d", "prn/d", pronouns["dating"]);
}

/* Gets pronouns based on the provided key (or user input) */
function getPronouns(key, other) {
  switch (key) {
    case "she":
      return {
        "subjective": "she",
        "objective": "her",
        "possessive": "her",
        "adjective": "hers",
        "reflexive": "herself",
        "honorific-abbr": "Ms.",
        "honorific": "miss",
        "adult": "woman",
        "youth": "girl",
        "parent": "mother",
        "child": "daughter",
        "sibling": "sister",
        "married": "wife",
        "dating": "girlfriend",
        "plurality": "singular"
      };
    case "he":
      return {
        "subjective": "he",
        "objective": "him",
        "possessive": "his",
        "adjective": "his",
        "reflexive": "himself",
        "honorific-abbr": "Mr.",
        "honorific": "mister",
        "adult": "man",
        "youth": "boy",
        "parent": "father",
        "child": "son",
        "sibling": "brother",
        "married": "husband",
        "dating": "boyfriend",
        "plurality": "singular"
      };
    case "they":
      return {
        "subjective": "they",
        "objective": "them",
        "possessive": "their",
        "adjective": "theirs",
        "reflexive": "themself",
        "honorific-abbr": "Mx.",
        "honorific": "mix",
        "adult": "person",
        "youth": "kid",
        "parent": "parent",
        "child": "child",
        "sibling": "sibling",
        "married": "spouse",
        "dating": "partner",
        "plurality": "plural"
      };
    case "first":
      return {
        "subjective": "I",
        "objective": "me",
        "possessive": "my",
        "adjective": "mine",
        "reflexive": "myself"
      };
    case "second":
      return {
        "subjective": "you",
        "objective": "you",
        "possessive": "your",
        "adjective": "yours",
        "reflexive": "yourself"
      };
    case "first-plural":
      return {
        "subjective": "we",
        "objective": "us",
        "possessive": "our",
        "adjective": "ours",
        "reflexive": "ourselves"
      };
    case "second-plural":
      return {
        "subjective": "you",
        "objective": "you",
        "possessive": "your",
        "adjective": "yours",
        "reflexive": "yourselves"
      };
    case "third-plural":
      return {
        "subjective": "they",
        "objective": "them",
        "possessive": "their",
        "adjective": "theirs",
        "reflexive": "themselves"
      };
    case "other":
      return other;
  }
}

/* Replaces pronoun keys in capital and lowercase with their equivalent pronouns */
function replacePronounSet(keyCapital, key, pronoun) {
  escapeAndReplace(keyCapital, capitalize(pronoun), true);
  escapeAndReplace(key, pronoun, true);
}

/* Replaces all point-of-view keys */
function replacePov(options) {
  let pronouns;
  if (options.pov == "third") {
    pronouns = getPronouns(options.preset, options.other);
    replacePronounSet("Pov/S", "pov/S", options.name);
    replacePronounSet("Pov/O", "pov/O", options.name);
    replacePronounSet("Pov/P", "pov/P", options.name + "'s");
    replacePronounSet("Pov/A", "pov/A", options.name + "'s");
    replacePronounSet("Pov/R", "pov/R", options.name + "'s self");
  } else {
    pronouns = getPronouns(options.pov, null);
    replacePronounSet("Pov/S", "pov/S", pronouns["subjective"]);
    replacePronounSet("Pov/O", "pov/O", pronouns["objective"]);
    replacePronounSet("Pov/P", "pov/P", pronouns["possessive"]);
    replacePronounSet("Pov/A", "pov/A", pronouns["adjective"]);
    replacePronounSet("Pov/R", "pov/R", pronouns["reflexive"]);
  }
  replacePronounSet("Pov/s", "pov/s", pronouns["subjective"]);
  replacePronounSet("Pov/o", "pov/o", pronouns["objective"]);
  replacePronounSet("Pov/p", "pov/p", pronouns["possessive"]);
  replacePronounSet("Pov/a", "pov/a", pronouns["adjective"]);
  replacePronounSet("Pov/r", "pov/r", pronouns["reflexive"]);
}

/* Replaces plural point-of-view keys */
function replacePlv(options) {
  let pronouns = getPronouns(options.pov + "-plural", null);
  replacePronounSet("Plv/s", "plv/s", pronouns["subjective"]);
  replacePronounSet("Plv/o", "plv/o", pronouns["objective"]);
  replacePronounSet("Plv/p", "plv/p", pronouns["possessive"]);
  replacePronounSet("Plv/a", "plv/a", pronouns["adjective"]);
  replacePronounSet("Plv/r", "plv/r", pronouns["reflexive"]);
}

/* Replaces additional terms specified by the user */
function replaceAlso(options) {
  Object.entries(options.also).forEach(([key, value]) => {
    escapeAndReplace(key, value, true);
  });
}

/* Turns a term into regexp format and uses that to replace it */
function escapeAndReplace(searchTerm, replaceValue, caseSensitive) {
  let searchTermEscaped = searchTerm.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&");
  const flags = caseSensitive ? "g" : "ig"
  if (searchTermEscaped[0].match(/[a-z]/i)) {
    searchTermEscaped = `\\b${searchTermEscaped}`
  }
  if (searchTermEscaped[searchTermEscaped.length - 1].match((/[a-z]/i))) {
    searchTermEscaped = `${searchTermEscaped}\\b`
  }
  const searchTermRegexp = new RegExp(searchTermEscaped, flags)
  walk(document.body, searchTermRegexp, replaceValue, directMethod);
}

/* Traverses a node and its children to run the provided replacement method */
function walk(node, searchTerm, replaceValue, replaceMethod) {
  if (node.contentEditable == "true" || node.type == "textarea" || node.type == "input") { return; }
  let child, next;
  switch (node.nodeType) {
    case 1:  /* ELEMENT_NODE */
    case 9:  /* DOCUMENT_NODE */
    case 11: /* DOCUMENT_FRAGMENT_NODE */
      child = node.firstChild;
      while (child) {
        next = child.nextSibling;
        walk(child, searchTerm, replaceValue, replaceMethod);
        child = next;
      }
      break;
    case 3: /* TEXT_NODE */
      replaceMethod(node, searchTerm, replaceValue);
  }
}

/* Replaces all of the provided terms in a node */
function directMethod(node, searchTerm, replaceValue) {
  node.nodeValue = node.nodeValue.replaceAll(searchTerm, replaceValue);
}

/* Replaces all verbs, not used for third-person plural */
/* TODO Is the "options" variable here readable? It's not replaceValue and that seems bad */
function verbMethod(node, searchTerm, options) {
  let match = node.nodeValue.match(searchTerm);
  if (match == null) { return; }
  const isCapital = /V/.test(match[1]);
  const verb = match[2];
  let tense = getTense(match[3]);
  const isTenseProvided = tense != null;
  if (!isTenseProvided) {
    tense = "PAST";
  }

  let replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, getPovIndex(options));

  if (isCapital) {
    replaceValue = capitalize(replaceValue);
  }

  if (isTenseProvided) {
    node.nodeValue = node.nodeValue.replace(searchTerm, replaceValue);
  } else {
    const searchTermShortVerb = /([Vv])r[Bb]\/([\w\s]+)\//
    node.nodeValue = node.nodeValue.replace(searchTermShortVerb, replaceValue);
  }

  verbMethod(node, searchTerm, options);
}

/* Replaces all verbs, used only for third-person plural */
function pluralThirdVerbMethod(node, searchTerm, options) {
  let match = node.nodeValue.match(searchTerm);
  if (match == null) { return; }
  const isCapital = /V/.test(match[1]);
  const isNamedActor = /B/.test(match[2]);
  const verb = match[3];
  let tense = getTense(match[4]);
  const isTenseProvided = tense != null;
  if (!isTenseProvided) {
    tense = "PAST";
  }

  let replaceValue;
  if (isNamedActor) {
    replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, 2);
  } else {
    replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, getPovIndex(options));
  }

  if (isCapital) {
    replaceValue = capitalize(replaceValue);
  }

  if (isTenseProvided) {
    node.nodeValue = node.nodeValue.replace(searchTerm, replaceValue);
  } else {
    const searchTermShortVerb = /([Vv])r([Bb])\/([\w\s]+)\//
    node.nodeValue = node.nodeValue.replace(searchTermShortVerb, replaceValue);
  }

  pluralThirdVerbMethod(node, searchTerm, options);
}

/* Replaces verbs by pronoun rather than POV, not used for plural */
function prnVerbMethod(node, searchTerm, options) {
  let match = node.nodeValue.match(searchTerm);
  if (match == null) { return; }
  const isCapital = /V/.test(match[1]);
  const verb = match[2];
  let tense = getTense(match[3]);
  const isTenseProvided = tense != null;
  if (!isTenseProvided) {
    tense = "PAST";
  }

  let replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, 2);

  if (isCapital) {
    replaceValue = capitalize(replaceValue);
  }

  if (isTenseProvided) {
    node.nodeValue = node.nodeValue.replace(searchTerm, replaceValue);
  } else {
    const searchTermShortVerb = /([Vv])r[Bb]\/([\w\s]+)\//
    node.nodeValue = node.nodeValue.replace(searchTermShortVerb, replaceValue);
  }

  prnVerbMethod(node, searchTerm, options);
}

/* Replaces verbs by pronoun rather than POV, used only for plural */
function pluralPrnVerbMethod(node, searchTerm, options) {
  let match = node.nodeValue.match(searchTerm);
  if (match == null) { return; }
  const isCapital = /V/.test(match[1]);
  const isNamedActor = /N/.test(match[2]);
  const verb = match[3];
  let tense = getTense(match[4]);
  const isTenseProvided = tense != null;
  if (!isTenseProvided) {
    tense = "PAST";
  }

  let replaceValue;
  if (isNamedActor) {
    replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, 2);
  } else {
    replaceValue = verbsHelper.getConjugation(verbsData, verb, tense, 5);
  }

  if (isCapital) {
    replaceValue = capitalize(replaceValue);
  }

  if (isTenseProvided) {
    node.nodeValue = node.nodeValue.replace(searchTerm, replaceValue);
  } else {
    const searchTermShortVerb = /([Vv])r([Bb])\/([\w\s]+)\//
    node.nodeValue = node.nodeValue.replace(searchTermShortVerb, replaceValue);
  }

  pluralPrnVerbMethod(node, searchTerm, options);
}

/* Returns the input word, capitalized */
function capitalize(word) {
  return word.charAt(0).toUpperCase() + word.slice(1);
}

/* Determines the index for point-of-view to be used when conjugating verbs */
function getPovIndex(options) {
  switch (options.pov) {
    case "first":
      return 0;
    case "second":
      return 1;
    case "third":
      if (getPronouns(options.preset, options.other).plurality == "singular") {
        return 2;
      } else { /* Plurality is plural, "they go" */
        return 5;
      }
  }
}

/* Gets the verb tense from a regexp match */
function getTense(match) {
  const tense = match.toUpperCase().replaceAll(" ", "_");
  const tenses = [
    // SIMPLE
    'SIMPLE_PAST',
    'PAST',
    'SIMPLE_PRESENT',
    'PRESENT',
    'SIMPLE_FUTURE',
    'FUTURE',
    // PROGRESSIVE
    'PROGRESSIVE_PAST',
    'PROGRESSIVE_PRESENT',
    'PROGRESSIVE_FUTURE',
    // PERFECT
    'PERFECT_PAST',
    'PERFECT_PRESENT',
    'PERFECT_FUTURE',
    // PERFECT PROGRESSIVE
    'PERFECT_PROGRESSIVE_PAST',
    'PERFECT_PROGRESSIVE_PRESENT',
    'PERFECT_PROGRESSIVE_FUTURE',
    // PARTICIPLE
    'PARTICIPLE_PRESENT',
    'PARTICIPLE_PAST',
  ];

  if (tenses.indexOf(tense) == -1) {
    return null;
  } else {
    return tense;
  }
}

replaceAll();