/* Copyright (c) 2020 Richard Rodger, MIT License */
/* $lab:coverage:off$ */

import { Gex } from 'gex'

/* $lab:coverage:on$ */


// NOTE: naming convention:
// key : pattern element key name string
// fix : pattern element match value
// val : potential match value



export interface Matcher {
  make(key: string, fix: any): MatchValue | undefined
  scan(mvs: MatchValue[], opts?: any): ScanResult
}

export interface ScanResult {
  complete: boolean,
  sound: boolean,
  gaps: any[],
  overs: any[],
  why?: string
}


export interface MatchValue {
  match(val: any): boolean
  same(mv: MatchValue | undefined): boolean
  kind: string
  fix: any
  meta: any
  keymap?: any
}


export class GexMatcher implements Matcher {
  constructor() {

  }

  make(key: string, fix: any) {
    if ('string' === typeof fix && fix.match(/[*?]/)) {
      let gex = Gex(fix)
      return {
        kind: 'gex',
        match: (val: any) => null != gex.on(val),
        fix: fix,
        meta: {},
        same(mv: MatchValue) {
          return null != mv && mv.kind === this.kind && mv.fix === this.fix
        }
      }
    }
    else return undefined
  }


  // TODO: pretty primitive, just looks for '*'
  scan(mvs: MatchValue[], opts?: any): ScanResult {
    let has_match_any = mvs.filter(mv => '*' === mv.fix).length > 0
    return {
      complete: has_match_any,
      sound: has_match_any,
      gaps: [],
      overs: [],
      why: 'no-star'
    }
  }
}


// TODO: space joins with &
// TODO: recongnize 'and' 'or'
// TODO: integers: <1, >1&<2, >2 is complete
// TODO: any: * is -Inf>=&&<=+Inf \ intervals - ie. gaps
// TODO: non-Number types: special case

// NOTE: '/' == '\\'
const IntervalRE = new RegExp([
  '^/s*', // optional whitespace
  '(=*[<>/(/[]?=*)?' + // 1, lenient operator symbol
  '/s*' + // optional whitespace
  '([-+0-9a-fA-FeEoOxX]+(/.([0-9a-fA-FeEoOxX]+))?)' + // 2,3,4 number
  '([/)/]]?)' + // 5, optional interval operator symbol
  '(' + // 6, start optional second term
  '/s*(,|&+|/|+|/./.)' + // 7, join
  '/s*' + // optional whitespace
  '(=*[<>]?=*)' + // 8, lenient operator symbol
  '/s*' + // optional whitespace
  '([-+.0-9a-fA-FeEoOxX]+)' + // 9, number
  '/s*' + // optional whitespace
  '([/)/]]?)' + // 10, interval operator symbol
  ')?' + // end optional second term
  '/s*$', // optional whitespace
].join('').replace(/\//g, '\\'))


export class IntervalMatcher implements Matcher {
  kind = 'interval'

  constructor() {
  }

  // == sames as =, <= same as =<
  static normop = (op: string) => null == op ? null :
    (((op.match(/([<>\(\)\[\]])/) || [])[1] || '') + ((op.match(/(=)/) || [])[1] || ''))


  #and = (lhs: any, rhs?: any) => function and(x: number) {
    return lhs(x) && rhs(x)
  }
  #or = (lhs: any, rhs?: any) => function or(x: number) {
    return lhs(x) || rhs(x)
  }
  #nil = (n: any) => function nil(x: any) { return false }
  #err = (n: any) => function err(x: any) { return false }
  #mgt = (n: any) => function gt(x: any) { return x > n }
  #mgte = (n: any) => function gte(x: any) { return x >= n }
  #mlt = (n: any) => function lt(x: any) { return x < n }
  #mlte = (n: any) => function lte(x: any) { return x <= n }
  #meq = (n: any) => function eq(x: any) { return x === n }


  make(key: string, fix: any) {
    if ('string' === typeof fix &&
      // At least one interval operator is required.
      // Exact numbers must be specified as '=X'
      fix.match(/[=<>.[()\]]/)) {

      let m = fix.match(IntervalRE)
      let meta = { jo: 'and', o0: 'err', n0: NaN, o1: 'err', n1: NaN }
      let match = (val: any) => false

      if (null != m) {
        let os0 = IntervalMatcher.normop(m[1]) || IntervalMatcher.normop(m[5])
        let os1 = IntervalMatcher.normop(m[8]) || IntervalMatcher.normop(m[10])

        let o0 =
          '=' === os0 ? this.#meq :
            '<' === os0 ? this.#mlt :
              ')' === os0 ? this.#mlt :
                '<=' === os0 ? this.#mlte :
                  ']' === os0 ? this.#mlte :
                    '>' === os0 ? this.#mgt :
                      '(' === os0 ? this.#mgt :
                        '>=' === os0 ? this.#mgte :
                          '[' === os0 ? this.#mgte :
                            this.#err

        let n0 = Number(m[2])
        let n1 = null == m[9] ? NaN : Number(m[9])

        let jos = m[7]

        let jo = null == jos ? this.#or :
          '&' === jos.substring(0, 1) ? this.#and :
            ',' === jos.substring(0, 1) ? this.#and :
              this.#or

        if ('..' === jos) {
          jo = this.#and
          o0 = this.#err === o0 ? this.#mgte : o0
          os1 = '' === os1 ? '<=' : os1
        }

        let o1 =
          null == os1 ? this.#nil :
            '=' === os1 ? this.#meq :
              '<' === os1 ? this.#mlt :
                ')' === os1 ? this.#mlt :
                  '<=' === os1 ? this.#mlte :
                    ']' === os1 ? this.#mlte :
                      '>' === os1 ? this.#mgt :
                        '>=' === os1 ? this.#mgte :
                          this.#err

        // merge ops if same number
        if (n0 === n1) {
          if ('=' === os0 && null != os1) {
            n1 = NaN
            o1 = this.#nil
            if (os1.includes('<')) {
              o0 = this.#mlte
            }
            else if (os1.includes('>')) {
              o0 = this.#mgte
            }
            else if (os1.includes('=')) {
              o0 = this.#meq
            }
            else {
              o0 = this.#err
            }
          }
          else if ('=' === os1 && null != os0) {
            n1 = NaN
            o1 = this.#nil
            if (os0.includes('<')) {
              o0 = this.#mlte
            }
            else if (os0.includes('>')) {
              o0 = this.#mgte
            }
            else {
              o0 = this.#err
            }
          }
        }


        // console.log(jo(o0(n0), o1(n1)), o0(n0), o1(n1))

        // if one sided interval, add the other side out to infinity
        if (this.#err !== o0) {
          if (this.#nil === o1) {
            if (this.#mlt === o0 || this.#mlte === o0) {
              o1 = o0
              n1 = n0
              o0 = this.#mgte
              n0 = Number.NEGATIVE_INFINITY
              jo = this.#and
            }
            else if (this.#mgt === o0 || this.#mgte === o0) {
              o1 = this.#mlte
              n1 = Number.POSITIVE_INFINITY
              jo = this.#and
            }
            // else this.meq ok as is
          }
        }

        // lower bound is always first so that interval sorting will work
        if (!isNaN(n1) && n1 < n0) {
          let to = o1
          let tn = n1
          n1 = n0
          n0 = tn

          // sensible heuristic: 20..10 means >=10&<=20
          if ('..' !== jos) {
            o1 = o0
            o0 = to
          }
        }

        let o0f = o0(n0)
        let o1f = o1(n1)
        let check = jo(o0f, o1f)

        meta = { jo: check.name, o0: o0f.name, n0, o1: o1f.name, n1 }
        match = (val: any) => {
          let res = false
          let n = parseFloat(val)

          if (!isNaN(n)) {
            res = check(n)
          }

          return res
        }

        return {
          kind: 'interval',
          fix,
          meta,
          match,
          same(mv: MatchValue) {
            return null != mv &&
              mv.kind === this.kind &&
              mv.meta.jo === this.meta.jo &&
              mv.meta.o0 === this.meta.o0 &&
              mv.meta.n0 === this.meta.n0 &&
              mv.meta.o1 === this.meta.o1 &&
              mv.meta.n1 === this.meta.n1
          }
        }
      }
    }
  }

  scan(mvs: MatchValue[], opts?: any): ScanResult {
    let scanres = {
      complete: false,
      sound: false,
      gaps: [] as any[],
      overs: [] as any[],
      lower: null,
      upper: null,
    }

    let bottom = Number.NEGATIVE_INFINITY
    let top = Number.POSITIVE_INFINITY

    let half_intervals: any[] = this.half_intervals(mvs)
    // console.log('H', half_intervals)

    half_intervals
      .reduce((c, h) => {
        // c: accumulated state
        // h: current half interval

        // console.log('\n\nRED')
        // console.dir(c, { depth: null })
        // console.dir(h, { depth: null })

        let heq = 'eq' === h.o
        let hlt = 'lt' === h.o
        let hlte = 'lte' === h.o
        let hgt = 'gt' === h.o
        let hgte = 'gte' === h.o
        let hn = h.n

        // NOTE: { == (or[or none

        if (null == c.lower) {
          let b = { n: bottom, o: 'gte' }
          c.lower = b
          c.upper = h

          if (!(bottom == hn && hgte)) {
            if (hgt || hgte) {
              // {-oo,hn}
              c.gaps.push([b, { n: hn, o: hgt ? 'lte' : 'lt', m: 0 }])
            }
            else if (heq) {
              // {-oo,hn)
              c.gaps.push([b, { n: hn, o: 'lte', m: 1 }])
            }
          }
        }
        else {
          let ueq = 'eq' === c.upper.o
          let ult = 'lt' === c.upper.o
          let ulte = 'lte' === c.upper.o
          let ugt = 'gt' === c.upper.o
          let ugte = 'hgte' === c.upper.o
          let un = c.upper.n
          let u = c.upper

          if (hn === un) {
            // un)[hn} OR {un](hn
            if ((ult && (hgte || heq)) ||
              ((ulte || ueq) && hgt)) {
              //c.upper = h
            }
            else if (ueq || ult || ulte) {
              // {un,hn}
              c.gaps.push([
                { n: un, o: (ueq || ulte) ? 'gt' : 'gte', m: 2, d: { u, h } },
                { n: hn, o: (heq || hgte) ? 'lt' : 'lte', m: 3 }
              ])
            }
            else {
              // TODO overlaps
              // console.log('OL-a', c, h)
            }
          }


          else if (un < hn) {
            if (hlt || hlte) {
              // console.log('OL-b', c, h)

              /*
              // overlap matches boundaries of c.upper.n..h.n
              c.overs.push([
                { n: un, o: c.upper.o, m: 8 },
                { n: hn, o: h.o, m: 9 }
              ])
              */

              //c.upper = h
            }
            else if (ueq || ult || ulte) {
              // {un,hn}
              c.gaps.push([
                { n: un, o: (ueq || ulte) ? 'gt' : 'gte', m: 4 },
                { n: hn, o: (heq || hgte) ? 'lt' : 'lte', m: 5 }
              ])
            }
          }
          // hn < un
          else {
            // console.log('hn < un', hn, un)
            c.overs.push([
              { n: hn, o: (heq || hgte) ? 'gte' : 'gt', m: 10 },
              { n: un, o: (ueq || ulte) ? 'lte' : 'lt', m: 11 },
            ])
          }

          c.upper = h
        }

        return c
      }, scanres)



    let last = 0 < half_intervals.length && half_intervals[half_intervals.length - 1]
    // {n,+oo]
    if (last && top !== last.n && last.o !== 'gt' && last.o !== 'gte') {
      scanres.gaps.push([
        { n: last.n, o: (last.o === 'eq' || last.o === 'lte') ? 'gt' : 'gte', m: 6 },
        { n: top, o: 'lte', m: 7 }
      ])
    }

    scanres.complete = 0 === scanres.gaps.length
    scanres.sound = 0 === scanres.overs.length

    return scanres
  }


  // NOTE: assumes n0<=n1
  half_intervals(mvs: MatchValue[]) {
    let half_intervals: any[] = []
    for (let mv of mvs) {
      half_intervals.push(
        [{ n: mv.meta.n0, o: mv.meta.o0 },
        { n: mv.meta.n1, o: mv.meta.o1 }]
      )
    }

    // canonical ordering of operations
    var os = ['lt', 'lte', 'eq', 'gte', 'gt']

    var hi = half_intervals
      .map(hh => [
        (isNaN(hh[0].n) || null == hh[0].n) ? null : hh[0],
        (isNaN(hh[1].n) || null == hh[1].n) ? null : hh[1]]
        .filter(h => null != h))

      // sorting on intervals, *not* half intervals
      .sort((a, b) => {

        // sort by first term numerically
        if (a[0].n < b[0].n) {
          return -1
        }
        else if (b[0].n < a[0].n) {
          return 1
        }
        else {
          // sort by first term operationally

          var a0i = os.indexOf(a[0].o)
          var b0i = os.indexOf(b[0].o)

          if (a0i < b0i) {
            return -1
          }
          else if (b0i < a0i) {
            return 1
          }
          else {
            // sort by second term numerically
            if (a[1].n < b[1].n) {
              return -1
            }
            else if (b[1].n < a[1].n) {
              return 1
            }
            else {
              // sort by second term operationally
              var a1i = os.indexOf(a[1].o)
              var b1i = os.indexOf(b[1].o)

              return a1i < b1i ? -1 : b1i < a1i ? 1 : 0
            }
          }
        }
      })

      .reduce((hv, hh) => hv.concat(...hh), [])

    // console.log(hi)
    return hi
  }
}