import
  std/[math, strutils]
import
  ../core/parser,
  ../core/value,
  ../core/interpreter,
  ../core/utils

proc floatCompare(n1, n2: MinValue): bool =
  let
    a: float = if n1.kind != minFloat: n1.intVal.float else: n1.floatVal
    b: float = if n2.kind != minFloat: n2.intVal.float else: n2.floatVal
  if a.classify == fcNan and b.classify == fcNan:
    return true
  else:
    const
      FLOAT_MIN_NORMAL = 2e-1022
      FLOAT_MAX_VALUE = (2-2e-52)*2e1023
      epsilon = 0.00001
    let
      absA = abs(a)
      absB = abs(b)
      diff = abs(a - b)
    if a == b:
      return true
    elif a == 0 or b == 0 or diff < FLOAT_MIN_NORMAL:
      return diff < (epsilon * FLOAT_MIN_NORMAL)
    else:
      return diff / min((absA + absB), FLOAT_MAX_VALUE) < epsilon

proc logic_module*(i: In) =
  let def = i.define()

  def.symbol(">") do (i: In):
    var n1, n2: MinValue
    i.reqTwoNumbersOrStrings n2, n1
    if n1.isNumber and n2.isNumber:
      if n1.isInt and n2.isInt:
        i.push newVal(n1.intVal > n2.intVal)
      elif n1.isInt and n2.isFloat:
        i.push newVal(n1.intVal.float > n2.floatVal)
      elif n1.isFloat and n2.isFloat:
        i.push newVal(n1.floatVal > n2.floatVal)
      elif n1.isFloat and n2.isInt:
        i.push newVal(n1.floatVal > n2.intVal.float)
    else:
      i.push newVal(n1.strVal > n2.strVal)

  def.symbol(">=") do (i: In):
    var n1, n2: MinValue
    i.reqTwoNumbersOrStrings n2, n1
    if n1.isNumber and n2.isNumber:
      if n1.isInt and n2.isInt:
        i.push newVal(n1.intVal >= n2.intVal)
      elif n1.isInt and n2.isFloat:
        i.push newVal(n1.intVal.float > n2.floatVal or floatCompare(n1, n2))
      elif n1.isFloat and n2.isFloat:
        i.push newVal(n1.floatVal > n2.floatVal or floatCompare(n1, n2))
      elif n1.isFloat and n2.isInt:
        i.push newVal(n1.floatVal > n2.intVal.float or floatCompare(n1, n2))
    else:
      i.push newVal(n1.strVal >= n2.strVal)

  def.symbol("<") do (i: In):
    var n1, n2: MinValue
    i.reqTwoNumbersOrStrings n1, n2
    if n1.isNumber and n2.isNumber:
      if n1.isInt and n2.isInt:
        i.push newVal(n1.intVal > n2.intVal)
      elif n1.isInt and n2.isFloat:
        i.push newVal(n1.intVal.float > n2.floatVal)
      elif n1.isFloat and n2.isFloat:
        i.push newVal(n1.floatVal > n2.floatVal)
      elif n1.isFloat and n2.isInt:
        i.push newVal(n1.floatVal > n2.intVal.float)
    else:
      i.push newVal(n1.strVal > n2.strVal)

  def.symbol("<=") do (i: In):
    var n1, n2: MinValue
    i.reqTwoNumbersOrStrings n1, n2
    if n1.isNumber and n2.isNumber:
      if n1.isInt and n2.isInt:
        i.push newVal(n1.intVal >= n2.intVal)
      elif n1.isInt and n2.isFloat:
        i.push newVal(n1.intVal.float > n2.floatVal or floatCompare(n1, n2))
      elif n1.isFloat and n2.isFloat:
        i.push newVal(n1.floatVal > n2.floatVal or floatCompare(n1, n2))
      elif n1.isFloat and n2.isInt:
        i.push newVal(n1.floatVal > n2.intVal.float or floatCompare(n1, n2))
    else:
      i.push newVal(n1.strVal >= n2.strVal)

  def.symbol("==") do (i: In):
    var n1, n2: MinValue
    let vals = i.expect("a", "a")
    n1 = vals[0]
    n2 = vals[1]
    if (n1.kind == minFloat or n2.kind == minFloat) and n1.isNumber and n2.isNumber:
      i.push newVal(floatCompare(n1, n2))
    else:
      i.push newVal(n1 == n2)

  def.symbol("!=") do (i: In):
    var n1, n2: MinValue
    let vals = i.expect("a", "a")
    n1 = vals[0]
    n2 = vals[1]
    if (n1.kind == minFloat or n2.kind == minFloat) and n1.isNumber and n2.isNumber:
      i.push newVal(not floatCompare(n1, n2))
    i.push newVal(not (n1 == n2))

  def.symbol("not") do (i: In):
    let vals = i.expect("bool")
    let b = vals[0]
    i.push newVal(not b.boolVal)

  def.symbol("and") do (i: In):
    let vals = i.expect("bool", "bool")
    let a = vals[0]
    let b = vals[1]
    i.push newVal(a.boolVal and b.boolVal)

  def.symbol("expect-all") do (i: In):
    let vals = i.expect("quot")
    let q = vals[0]
    var c = 0
    for v in q.qVal:
      if not v.isQuotation:
        raiseInvalid("A quotation of quotations is expected")
      var vv = v
      i.dequote vv
      let r = i.pop
      c.inc()
      if not r.isBool:
        raiseInvalid("Quotation #$# does not evaluate to a boolean value" % [$c])
      if not r.boolVal:
        i.push r
        return
    i.push true.newVal

  def.symbol("or") do (i: In):
    let vals = i.expect("bool", "bool")
    let a = vals[0]
    let b = vals[1]
    i.push newVal(a.boolVal or b.boolVal)

  def.symbol("expect-any") do (i: In):
    let vals = i.expect("quot")
    let q = vals[0]
    var c = 0
    for v in q.qVal:
      if not v.isQuotation:
        raiseInvalid("A quotation of quotations is expected")
      var vv = v
      i.dequote vv
      let r = i.pop
      c.inc()
      if not r.isBool:
        raiseInvalid("Quotation #$# does not evaluate to a boolean value" % [$c])
      if r.boolVal:
        i.push r
        return
    i.push false.newVal

  def.symbol("xor") do (i: In):
    let vals = i.expect("bool", "bool")
    let a = vals[0]
    let b = vals[1]
    i.push newVal(a.boolVal xor b.boolVal)

  def.symbol("string?") do (i: In):
    if i.pop.kind == minString:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("integer?") do (i: In):
    if i.pop.kind == minInt:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("float?") do (i: In):
    if i.pop.kind == minFloat:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("null?") do (i: In):
    if i.pop.kind == minNull:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("number?") do (i: In):
    let a = i.pop
    if a.kind == minFloat or a.kind == minInt:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("boolean?") do (i: In):
    if i.pop.kind == minBool:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("quotation?") do (i: In):
    if i.pop.kind == minQuotation:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("quoted-symbol?") do (i: In):
    let item = i.pop
    if item.kind == minQuotation and item.qVal.len == 1 and item.qVal[0].kind == minSymbol:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("stringlike?") do (i: In):
    if i.pop.isStringLike:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("dictionary?") do (i: In):
    if i.pop.isDictionary:
      i.push true.newVal
    else:
      i.push false.newVal

  def.symbol("type?") do (i: In):
    let vals = i.expect("'sym", "a")
    let t = vals[0].getString
    let v = vals[1]
    let res = i.validateValueType(t, v)
    i.push res.newVal

  def.symbol("&&") do (i: In):
    i.pushSym("expect-all")

  def.symbol("||") do (i: In):
    i.pushSym("expect-any")

  def.finalize("logic")