/* suffix-thumb 5.0.2 MIT */
// 01- full-word exceptions
const checkEx = function (str, ex = {}) {
  if (ex.hasOwnProperty(str)) {
    return ex[str]
  }
  return null
};

// 02- suffixes that pass our word through
const checkSame = function (str, same = []) {
  for (let i = 0; i < same.length; i += 1) {
    if (str.endsWith(same[i])) {
      return str
    }
  }
  return null
};

// 03- check rules - longest first
const checkRules = function (str, fwd, both = {}) {
  fwd = fwd || {};
  let max = str.length - 1;
  // look for a matching suffix
  for (let i = max; i >= 1; i -= 1) {
    let size = str.length - i;
    let suff = str.substring(size, str.length);
    // check fwd rules, first
    if (fwd.hasOwnProperty(suff) === true) {
      return str.slice(0, size) + fwd[suff]
    }
    // check shared rules
    if (both.hasOwnProperty(suff) === true) {
      return str.slice(0, size) + both[suff]
    }
  }
  // try a fallback transform
  if (fwd.hasOwnProperty('')) {
    return str += fwd['']
  }
  if (both.hasOwnProperty('')) {
    return str += both['']
  }
  return null
};

//sweep-through all suffixes
const convert$1 = function (str = '', model = {}) {
  // 01- check exceptions
  let out = checkEx(str, model.ex);
  // 02 - check same
  out = out || checkSame(str, model.same);
  // check forward and both rules
  out = out || checkRules(str, model.fwd, model.both);
  //return unchanged
  out = out || str;
  return out
};

const flipObj = function (obj) {
  return Object.entries(obj).reduce((h, a) => {
    h[a[1]] = a[0];
    return h
  }, {})
};

const reverse = function (model = {}) {
  return {
    reversed: true,
    // keep these two
    both: flipObj(model.both),
    ex: flipObj(model.ex),
    // swap this one in
    fwd: model.rev || {}
  }
};

// make sure inputs are not impossible to square-up
const validate = function (pairs, opts = {}) {
  let left = new Set();
  let right = new Set();
  pairs = pairs.filter(a => {
    if (left.has(a[0])) {
      // console.log('dupe', a)
      return false
    }
    if (right.has(a[1])) {
      // console.log('dupe', a)
      return false
    }
    left.add(a[0]);
    right.add(a[1]);

    // ensure pairs are aligned by prefix
    // if (a[0].substring(0, 1) !== a[1].substring(0, 1)) {
    //   console.log('pair not aligned at prefix:', a)
    //   return false
    // }
    return true
  });
  return pairs
};

const prep = function (pairs, ex) {
  // remove dupes
  pairs = validate(pairs);
  // ensure pairs are prefix aligned, in the first-place
  return pairs.filter(arr => {
    let [a, b] = arr;
    if (a.substring(0, 1) !== b.substring(0, 1)) {
      ex[a] = b;
      return false
    }
    return true
  })
};

// get the suffix diff between a and b
const generateRule = function (pair, peekLen = 0) {
  let all = [];
  let [from, to] = pair;
  for (let i = 0; i < from.length; i += 1) {
    if (from[i] === to[i]) {
      all.push(from[i]);
    } else {
      break
    }
  }
  let prefix = all.length - peekLen;
  // is our suffix just the whole word? (not allowed!)
  if (peekLen >= all.length) {
    return null
  }
  return {
    from: from.substring(prefix),
    to: to.substring(prefix)
  }
};

// check a rule
const convert = function (str, rule) {
  if (rule.from.length >= str.length) {
    return null
  }
  if (str.endsWith(rule.from)) {
    let len = str.length - rule.from.length;
    let pre = str.slice(0, len);
    // if (str === 'agenouiller') {
    //   console.log(str, rule, pre + rule.to)
    // }
    return pre + rule.to
  }
  return null
};
// console.log(convert('asdfoo', { from: 'foo', to: 'dog' }))

const getPercent = (part, total) => {
  if (total === 0) {
    return 100
  }
  let num = (part / total) * 100;
  num = Math.round(num * 10) / 10;
  return num;
};

// decide whether this rule performs well or not
const considerRule = function (rule, pairs) {
  let total = 0;
  let clear = new Set();
  if (!rule) {
    return { total, percent: 0, rule, clear, count: 0 }
  }
  if (pairs.length === 0) {
    return { total, percent: 100, rule, clear, count: 0 }
  }
  pairs.forEach(pair => {
    let res = convert(pair[0], rule);
    if (res !== null) {
      total += 1;
      if (res === pair[1]) {
        clear.add(pair[0]);
      }
    }
  });
  return {
    total,
    count: clear.size,
    percent: getPercent(clear.size, total),
    rule,
    clear
  }
};

const findRules = function (pairs, finished, opts) {
  let pending = pairs.slice(0);
  let rules = {};
  // small rules first
  for (let peek = 0; peek < 6; peek += 1) {
    for (let i = 0; i < pending.length; i += 1) {
      let rule = generateRule(pending[i], peek);
      let result = considerRule(rule, pending);
      // did it do okay?
      if (result.rule && result.percent > opts.threshold && result.count > opts.min) {
        // ensure it does not interfere with existing pairs
        let res2 = considerRule(rule, finished);
        if (res2.percent < 100) {
          continue
        }

        // add it to our rules
        rules[rule.from] = rule.to;
        // update pending/finished lists
        pending = pending.filter(p => {
          if (result.clear.has(p[0])) {
            finished.push(p);
            return false
          }
          return true
        });
      }
    }
  }
  return { rules, pending, finished }
};

// some rules are also good in reverse
const shareBackward = function (fwd, rev, opts) {
  let both = {};
  let pending = rev.slice(0);
  let finished = [];
  let rules = Object.entries(fwd).reverse();
  rules.forEach(a => {
    let rule = { from: a[1], to: a[0] };
    if (!rule.to) {
      return
    }
    let result = considerRule(rule, rev);
    // did it do okay?
    if (result.percent > opts.threshold) {
      // move it to 'both' rules
      both[rule.to] = rule.from;
      delete fwd[rule.to];
      // update finished/pending lists
      pending = pending.filter(a => {
        if (result.clear.has(a[0])) {
          finished.push(a);
          return false
        }
        return true
      });
    }
  });
  return {
    fwd,
    both,
    revPairs: {
      pending,
      finished
    }
  }
};

const defaults = {
  threshold: 80,
  min: 0
};
const swap$1 = (a) => [a[1], a[0]];

const learn = function (pairs, opts = {}) {
  opts = Object.assign({}, defaults, opts);
  let ex = {};
  let rev = {};
  pairs = prep(pairs, ex);
  // get forward-dir rules
  let { rules, pending, finished } = findRules(pairs, [], opts);
  // move some to both
  let { fwd, both, revPairs } = shareBackward(rules, pairs.map(swap$1), opts);
  // generate remaining reverse-dir rules
  let pendingBkwd = [];
  if (opts.reverse !== false) {
    // console.log(revPairs.pending)
    let bkwd = findRules(revPairs.pending, revPairs.finished, opts);
    pendingBkwd = bkwd.pending;
    rev = bkwd.rules;
  }
  // console.log(pending.length, 'pending fwd')
  // console.log(pendingBkwd.length, 'pending Bkwd')
  // add anything remaining as an exception
  if (opts.min <= 1) {
    pending.forEach(arr => {
      ex[arr[0]] = arr[1];
    });
    pendingBkwd.forEach(arr => {
      ex[arr[1]] = arr[0];
    });
  }
  return {
    fwd,
    both,
    rev,
    ex,
  }
};

// longest common prefix
const findOverlap = (from, to) => {
  let all = [];
  for (let i = 0; i < from.length; i += 1) {
    if (from[i] === to[i]) {
      all.push(from[i]);
    } else {
      break
    }
  }
  return all.join('')
};

// run-length encode any shared prefix
let compress$1 = function (key, val) {
  let prefix = findOverlap(key, val);
  if (prefix.length < 1) {
    return val
  }
  let out = prefix.length + val.substr(prefix.length);
  return out
};
// console.log(compress('fixture', 'fixturing'))

const pack = function (obj) {
  let byVal = {};
  Object.keys(obj).forEach(k => {
    let val = obj[k];
    byVal[val] = byVal[val] || [];
    byVal[val].push(k);
  });
  let out = [];
  Object.keys(byVal).forEach(val => {
    out.push(`${val}:${byVal[val].join(',')}`);
  });
  return out.join('¦')
};

const packObj = function (obj = {}) {
  let tmp = {};
  Object.keys(obj).forEach(k => {
    let val = compress$1(k, obj[k]);// compress any shared prefix
    tmp[k] = val;
  });
  return pack(tmp)
};

const compress = function (model) {
  let out = {
    fwd: packObj(model.fwd),
    both: packObj(model.both),
    rev: packObj(model.rev),
    ex: packObj(model.ex),
  };
  return out
};


// let model = {
//   fwd: {
//     foo: 'food',
//     bar: 'bard',
//     cool: 'nice'
//   }
// }
// console.log(compress(model))

const prefix = /^([0-9]+)/;

const toObject = function (txt) {
  let obj = {};
  txt.split('¦').forEach(str => {
    let [key, vals] = str.split(':');
    vals = (vals || '').split(',');
    vals.forEach(val => {
      obj[val] = key;
    });
  });
  return obj
};

const growObject = function (key = '', val = '') {
  val = String(val);
  let m = val.match(prefix);
  if (m === null) {
    return val
  }
  let num = Number(m[1]) || 0;
  let pre = key.substring(0, num);
  let full = pre + val.replace(prefix, '');
  return full
};

const unpackOne = function (str) {
  let obj = toObject(str);
  return Object.keys(obj).reduce((h, k) => {
    h[k] = growObject(k, obj[k]);
    return h
  }, {})
};

const uncompress = function (model = {}) {
  if (typeof model === 'string') {
    model = JSON.parse(model);
  }
  model.fwd = unpackOne(model.fwd || '');
  model.both = unpackOne(model.both || '');
  model.rev = unpackOne(model.rev || '');
  model.ex = unpackOne(model.ex || '');
  return model
};

const cyan = str => '\x1b[36m' + str + '\x1b[0m';
const blue = str => '\x1b[34m' + str + '\x1b[0m';

const percent = (part, total) => {
  let num = (part / total) * 100;
  num = Math.round(num * 10) / 10;
  return num + '%'
};

const swap = (a) => [a[1], a[0]];

const getNum = function (pairs, model) {
  let right = 0;
  pairs.forEach(a => {
    let have = convert$1(a[0], model);
    if (have === a[1]) {
      right += 1;
    } else {
      console.log('❌ ', a, '→ ' + have);
    }
  });
  return percent(right, pairs.length)
};

const test = function (pairs, model = {}) {
  pairs = validate(pairs);
  let fwdScore = getNum(pairs, model);
  let bkwdScore = getNum(pairs.map(swap), reverse(model));
  console.log(`${blue(fwdScore)}  -  🔄 ${cyan(bkwdScore)}`);
};

export { compress, convert$1 as convert, learn, reverse, test, uncompress, validate };