;(function (exports) { // nothing in here is node-specific.

// See http://semver.org/
// This implementation is a *hair* less strict in that it allows
// v1.2.3 things, and also tags that don't begin with a char.

var semver = "\\s*[v=]*\\s*([0-9]+)"        // major
           + "\\.([0-9]+)"                  // minor
           + "\\.([0-9]+)"                  // patch
           + "(-[0-9]+-?)?"                 // build
           + "([a-zA-Z-+][a-zA-Z0-9-\.:]*)?" // tag
  , exprComparator = "^((<|>)?=?)\s*("+semver+")$|^$"
  , xRangePlain = "[v=]*([0-9]+|x|X|\\*)"
                + "(?:\\.([0-9]+|x|X|\\*)"
                + "(?:\\.([0-9]+|x|X|\\*)"
                + "([a-zA-Z-][a-zA-Z0-9-\.:]*)?)?)?"
  , xRange = "((?:<|>)=?)?\\s*" + xRangePlain
  , exprSpermy = "(?:~>?)"+xRange
  , expressions = exports.expressions =
    { parse : new RegExp("^\\s*"+semver+"\\s*$")
    , parsePackage : new RegExp("^\\s*([^\/]+)[-@](" +semver+")\\s*$")
    , parseRange : new RegExp(
        "^\\s*(" + semver + ")\\s+-\\s+(" + semver + ")\\s*$")
    , validComparator : new RegExp("^"+exprComparator+"$")
    , parseXRange : new RegExp("^"+xRange+"$")
    , parseSpermy : new RegExp("^"+exprSpermy+"$")
    }


Object.getOwnPropertyNames(expressions).forEach(function (i) {
  exports[i] = function (str) {
    return ("" + (str || "")).match(expressions[i])
  }
})

exports.rangeReplace = ">=$1 <=$7"
exports.clean = clean
exports.compare = compare
exports.rcompare = rcompare
exports.satisfies = satisfies
exports.gt = gt
exports.gte = gte
exports.lt = lt
exports.lte = lte
exports.eq = eq
exports.neq = neq
exports.cmp = cmp
exports.inc = inc

exports.valid = valid
exports.validPackage = validPackage
exports.validRange = validRange
exports.maxSatisfying = maxSatisfying

exports.replaceStars = replaceStars
exports.toComparators = toComparators

function stringify (version) {
  var v = version
  return [v[1]||'', v[2]||'', v[3]||''].join(".") + (v[4]||'') + (v[5]||'')
}

function clean (version) {
  version = exports.parse(version)
  if (!version) return version
  return stringify(version)
}

function valid (version) {
  if (typeof version !== "string") return null
  return exports.parse(version) && version.trim().replace(/^[v=]+/, '')
}

function validPackage (version) {
  if (typeof version !== "string") return null
  return version.match(expressions.parsePackage) && version.trim()
}

// range can be one of:
// "1.0.3 - 2.0.0" range, inclusive, like ">=1.0.3 <=2.0.0"
// ">1.0.2" like 1.0.3 - 9999.9999.9999
// ">=1.0.2" like 1.0.2 - 9999.9999.9999
// "<2.0.0" like 0.0.0 - 1.9999.9999
// ">1.0.2 <2.0.0" like 1.0.3 - 1.9999.9999
var starExpression = /(<|>)?=?\s*\*/g
  , starReplace = ""
  , compTrimExpression = new RegExp("((<|>)?=|<|>)\\s*("
                                    +semver+"|"+xRangePlain+")", "g")
  , compTrimReplace = "$1$3"

function toComparators (range) {
  var ret = (range || "").trim()
    .replace(expressions.parseRange, exports.rangeReplace)
    .replace(compTrimExpression, compTrimReplace)
    .split(/\s+/)
    .join(" ")
    .split("||")
    .map(function (orchunk) {
      return orchunk
        .split(" ")
        .map(replaceXRanges)
        .map(replaceSpermies)
        .map(replaceStars)
        .join(" ").trim()
    })
    .map(function (orchunk) {
      return orchunk
        .trim()
        .split(/\s+/)
        .filter(function (c) { return c.match(expressions.validComparator) })
    })
    .filter(function (c) { return c.length })
  return ret
}

function replaceStars (stars) {
  return stars.trim().replace(starExpression, starReplace)
}

// "2.x","2.x.x" --> ">=2.0.0- <2.1.0-"
// "2.3.x" --> ">=2.3.0- <2.4.0-"
function replaceXRanges (ranges) {
  return ranges.split(/\s+/)
               .map(replaceXRange)
               .join(" ")
}

function replaceXRange (version) {
  return version.trim().replace(expressions.parseXRange,
                                function (v, gtlt, M, m, p, t) {
    var anyX = !M || M.toLowerCase() === "x" || M === "*"
               || !m || m.toLowerCase() === "x" || m === "*"
               || !p || p.toLowerCase() === "x" || p === "*"
      , ret = v

    if (gtlt && anyX) {
      // just replace x'es with zeroes
      ;(!M || M === "*" || M.toLowerCase() === "x") && (M = 0)
      ;(!m || m === "*" || m.toLowerCase() === "x") && (m = 0)
      ;(!p || p === "*" || p.toLowerCase() === "x") && (p = 0)
      ret = gtlt + M+"."+m+"."+p+"-"
    } else if (!M || M === "*" || M.toLowerCase() === "x") {
      ret = "*" // allow any
    } else if (!m || m === "*" || m.toLowerCase() === "x") {
      // append "-" onto the version, otherwise
      // "1.x.x" matches "2.0.0beta", since the tag
      // *lowers* the version value
      ret = ">="+M+".0.0- <"+(+M+1)+".0.0-"
    } else if (!p || p === "*" || p.toLowerCase() === "x") {
      ret = ">="+M+"."+m+".0- <"+M+"."+(+m+1)+".0-"
    }
    return ret
  })
}

// ~, ~> --> * (any, kinda silly)
// ~2, ~2.x, ~2.x.x, ~>2, ~>2.x ~>2.x.x --> >=2.0.0 <3.0.0
// ~2.0, ~2.0.x, ~>2.0, ~>2.0.x --> >=2.0.0 <2.1.0
// ~1.2, ~1.2.x, ~>1.2, ~>1.2.x --> >=1.2.0 <1.3.0
// ~1.2.3, ~>1.2.3 --> >=1.2.3 <1.3.0
// ~1.2.0, ~>1.2.0 --> >=1.2.0 <1.3.0
function replaceSpermies (version) {
  return version.trim().replace(expressions.parseSpermy,
                                function (v, gtlt, M, m, p, t) {
    if (gtlt) throw new Error(
      "Using '"+gtlt+"' with ~ makes no sense. Don't do it.")

    if (!M || M.toLowerCase() === "x") {
      return ""
    }
    // ~1 == >=1.0.0- <2.0.0-
    if (!m || m.toLowerCase() === "x") {
      return ">="+M+".0.0- <"+(+M+1)+".0.0-"
    }
    // ~1.2 == >=1.2.0- <1.3.0-
    if (!p || p.toLowerCase() === "x") {
      return ">="+M+"."+m+".0- <"+M+"."+(+m+1)+".0-"
    }
    // ~1.2.3 == >=1.2.3- <1.3.0-
    t = t || "-"
    return ">="+M+"."+m+"."+p+t+" <"+M+"."+(+m+1)+".0-"
  })
}

function validRange (range) {
  range = replaceStars(range)
  var c = toComparators(range)
  return (c.length === 0)
       ? null
       : c.map(function (c) { return c.join(" ") }).join("||")
}

// returns the highest satisfying version in the list, or undefined
function maxSatisfying (versions, range) {
  return versions
    .filter(function (v) { return satisfies(v, range) })
    .sort(compare)
    .pop()
}
function satisfies (version, range) {
  version = valid(version)
  if (!version) return false
  range = toComparators(range)
  for (var i = 0, l = range.length ; i < l ; i ++) {
    var ok = false
    for (var j = 0, ll = range[i].length ; j < ll ; j ++) {
      var r = range[i][j]
        , gtlt = r.charAt(0) === ">" ? gt
               : r.charAt(0) === "<" ? lt
               : false
        , eq = r.charAt(!!gtlt) === "="
        , sub = (!!eq) + (!!gtlt)
      if (!gtlt) eq = true
      r = r.substr(sub)
      r = (r === "") ? r : valid(r)
      ok = (r === "") || (eq && r === version) || (gtlt && gtlt(version, r))
      if (!ok) break
    }
    if (ok) return true
  }
  return false
}

// return v1 > v2 ? 1 : -1
function compare (v1, v2) {
  var g = gt(v1, v2)
  return g === null ? 0 : g ? 1 : -1
}

function rcompare (v1, v2) {
  return compare(v2, v1)
}

function lt (v1, v2) { return gt(v2, v1) }
function gte (v1, v2) { return !lt(v1, v2) }
function lte (v1, v2) { return !gt(v1, v2) }
function eq (v1, v2) { return gt(v1, v2) === null }
function neq (v1, v2) { return gt(v1, v2) !== null }
function cmp (v1, c, v2) {
  switch (c) {
    case ">": return gt(v1, v2)
    case "<": return lt(v1, v2)
    case ">=": return gte(v1, v2)
    case "<=": return lte(v1, v2)
    case "==": return eq(v1, v2)
    case "!=": return neq(v1, v2)
    case "===": return v1 === v2
    case "!==": return v1 !== v2
    default: throw new Error("Y U NO USE VALID COMPARATOR!? "+c)
  }
}

// return v1 > v2
function num (v) {
  return v === undefined ? -1 : parseInt((v||"0").replace(/[^0-9]+/g, ''), 10)
}
function gt (v1, v2) {
  v1 = exports.parse(v1)
  v2 = exports.parse(v2)
  if (!v1 || !v2) return false

  for (var i = 1; i < 5; i ++) {
    v1[i] = num(v1[i])
    v2[i] = num(v2[i])
    if (v1[i] > v2[i]) return true
    else if (v1[i] !== v2[i]) return false
  }
  // no tag is > than any tag, or use lexicographical order.
  var tag1 = v1[5] || ""
    , tag2 = v2[5] || ""

  // kludge: null means they were equal.  falsey, and detectable.
  // embarrassingly overclever, though, I know.
  return tag1 === tag2 ? null
         : !tag1 ? true
         : !tag2 ? false
         : tag1 > tag2
}

function inc (version, release) {
  version = exports.parse(version)
  if (!version) return null

  var parsedIndexLookup =
    { 'major': 1
    , 'minor': 2
    , 'patch': 3
    , 'build': 4 }
  var incIndex = parsedIndexLookup[release]
  if (incIndex === undefined) return null

  var current = num(version[incIndex])
  version[incIndex] = current === -1 ? 1 : current + 1

  for (var i = incIndex + 1; i < 5; i ++) {
    if (num(version[i]) !== -1) version[i] = "0"
  }

  if (version[4]) version[4] = "-" + version[4]
  version[5] = ""

  return stringify(version)
}
})(typeof exports === "object" ? exports : semver = {})