open System

open System.Globalization

open System.Text.RegularExpressions

let asOption = function true, v -> Some v | _ -> None

let (|StringEqualsIgnoreCase|_|) (s1:string) s2 =

if s1.Equals(s2, StringComparison.OrdinalIgnoreCase)

then Some () else None

let (|OneOfIgnoreCase|_|) set str =

if Array.exists (fun s -> StringComparer.OrdinalIgnoreCase.Compare(s, str) = 0) set then Some() else None

let msDateRegex = lazy Regex(@"^/Date\((-?\d+)([-+]\d+)?\)/$", RegexOptions.Compiled)

let dateTimeStyles = DateTimeStyles.AllowWhiteSpaces ||| DateTimeStyles.RoundtripKind

let ParseISO8601FormattedDateTime (text : string) cultureInfo =

match DateTime.TryParse(text, cultureInfo, dateTimeStyles) with

| true, d -> d |> Some

| false, _ -> None

type TextConversions private() =

static member val DefaultMissingValues = [| "NaN"; "NA"; "N/A"; "#N/A"; ":"; "-"; "TBA"; "TBD" |]

static member val DefaultNonCurrencyAdorners = [| '%'; '‰'; '‱' |] |> Set.ofArray

static member val DefaultCurrencyAdorners = [| '¤'; '$'; '¢'; '£'; '¥'; '₱'; '﷼'; '₤'; '₭'; '₦'; '₨'; '₩'; '₮'; '€'; '฿'; '₡'; '៛'; '؋'; '₴'; '₪'; '₫'; '₹'; 'ƒ' |] |> Set.ofArray

static member val private DefaultRemovableAdornerCharacters =

Set.union TextConversions.DefaultNonCurrencyAdorners TextConversions.DefaultCurrencyAdorners

static member private RemoveAdorners (value : string) =

String(value.ToCharArray() |> Array.filter (not << TextConversions.DefaultRemovableAdornerCharacters.Contains))

static member AsString str =

if String.IsNullOrWhiteSpace str then None else Some str

static member AsInteger cultureInfo text =

Int32.TryParse(TextConversions.RemoveAdorners text, NumberStyles.Integer, cultureInfo) |> asOption

static member AsFloat missingValues useNoneForMissingValues cultureInfo (text:string) =

match text.Trim() with

| OneOfIgnoreCase missingValues -> if useNoneForMissingValues then None else Some Double.NaN

| _ -> Double.TryParse(text, NumberStyles.Any, cultureInfo)

|> asOption

|> Option.bind (fun f -> if useNoneForMissingValues && Double.IsNaN f then None else Some f)

static member AsBoolean (text:string) =

match text.Trim() with

| StringEqualsIgnoreCase "true" | StringEqualsIgnoreCase "yes" | StringEqualsIgnoreCase "1" -> Some true

| StringEqualsIgnoreCase "false" | StringEqualsIgnoreCase "no" | StringEqualsIgnoreCase "0" -> Some false

| _ -> None

static member AsDateTime cultureInfo (text:string) =

let matchesMS = msDateRegex.Value.Match (text.Trim())

if matchesMS.Success then

matchesMS.Groups.[1].Value

|> Double.Parse

|> DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds

|> Some

else

match ParseISO8601FormattedDateTime text cultureInfo with

| Some d when d.Kind = DateTimeKind.Unspecified -> new DateTime(d.Ticks, DateTimeKind.Local) |> Some

| x -> x

static member AsDateTimeOffset cultureInfo (text:string) =

let getTimeSpanFromHourMin (hourMin:int) =

let hr = (hourMin/100) |> float |> TimeSpan.FromHours

let min = (hourMin%100) |> float |> TimeSpan.FromMinutes

hr.Add min

let offset (str : string) =

match Int32.TryParse str with

| true, v -> getTimeSpanFromHourMin v |> Some

| false, _ -> None

let matchesMS = msDateRegex.Value.Match (text.Trim())

if matchesMS.Success && matchesMS.Groups.[2].Success && matchesMS.Groups.[2].Value.Length = 5 then

match offset matchesMS.Groups.[2].Value with

| Some ofst ->

matchesMS.Groups.[1].Value

|> Double.Parse

|> DateTimeOffset(1970, 1, 1, 0, 0, 0, ofst).AddMilliseconds

|> Some

| None -> None

else

match ParseISO8601FormattedDateTime text cultureInfo with

| Some d when d.Kind <> DateTimeKind.Unspecified ->

match DateTimeOffset.TryParse(text, cultureInfo, dateTimeStyles) with

| true, dto -> dto |> Some

| false, _ -> None

| _ -> None

static member AsTimeSpan (cultureInfo: CultureInfo) (text:string) =

match TimeSpan.TryParse(text, cultureInfo) with

| true, t -> Some t

| _ -> None

static member AsGuid (text:string) =

Guid.TryParse(text.Trim()) |> asOption

let getUnicodeSurrogatePair num =

let codePoint = num - 0x010000u

let HIGH_TEN_BIT_MASK = 0xFFC00u

let LOW_TEN_BIT_MASK = 0x003FFu

let leadSurrogate = (codePoint &&& HIGH_TEN_BIT_MASK >>> 10) + 0xD800u

let trailSurrogate = (codePoint &&& LOW_TEN_BIT_MASK) + 0xDC00u

char leadSurrogate, char trailSurrogate