Imports System.IO
Imports System.Net
Imports System.Threading
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq

Module Module1

    ' The authentication key (API Key).
    ' Get your own by registering at https://app.pdf.co
    Const API_KEY As String = "***********************************"

    ' Source PDF file
    Const SourceFile As String = ".\sample.pdf"

    ' Comma-separated list of page indices (or ranges) to process. Leave empty for all pages. Example: '0,2-5,7-'.
    Const Pages As String = ""

    ' PDF document password. Leave empty for unprotected documents.
    Const Password As String = ""

    ' Search string.
    Const SearchString As String = "\d{1,}\.\d\d" 'Regular expression To find numbers Like '100.00'
    ' Note: Do Not use `+` char in regex, but use `{1,}` instead.
    ' `+` char Is valid for URL And will Not be escaped, And it will become a space char on the server side.

    ' Enable regular expressions (Regex) 
    Const RegexSearch As Boolean = True

    ' (!) Make asynchronous job
    Const Async As Boolean = True

    Sub Main()

        ' Create standard .NET web client instance
        Dim webClient As WebClient = New WebClient()

        ' Set API Key
        webClient.Headers.Add("x-api-key", API_KEY)

        ' 1. RETRIEVE THE PRESIGNED URL TO UPLOAD THE FILE.
        ' * If you already have a direct file URL, skip to the step 3.

        ' Prepare URL for `Get Presigned URL` API call
        Dim query As String = Uri.EscapeUriString(String.Format(
            "https://api.pdf.co/v1/file/upload/get-presigned-url?contenttype=application/octet-stream&name={0}",
            Path.GetFileName(SourceFile)))

        Try
            ' Execute request
            Dim response As String = webClient.DownloadString(query)

            ' Parse JSON response
            Dim json As JObject = JObject.Parse(response)

            If json("error").ToObject(Of Boolean) = False Then
                ' Get URL to use for the file upload
                Dim uploadUrl As String = json("presignedUrl").ToString()
                ' Get URL of uploaded file to use with later API calls
                Dim uploadedFileUrl As String = json("url").ToString()

                ' 2. UPLOAD THE FILE TO CLOUD.
                webClient.Headers.Add("content-type", "application/octet-stream")
                webClient.UploadFile(uploadUrl, "PUT", SourceFile) ' You can use UploadData() instead if your file is byte array or Stream

                ' Set JSON content type
                webClient.Headers.Add("Content-Type", "application/json")

                ' 3. MAKE UPLOADED PDF FILE SEARCHABLE

                ' Prepare URL for PDF text search API call.
                ' See documentation: https : //app.pdf.co/documentation/api/1.0/pdf/find.html
                Dim url As String = "https://api.pdf.co/v1/pdf/find"

                ' Prepare requests params as JSON
                ' See documentation: https : //apidocs.pdf.co
                Dim parameters As New Dictionary(Of String, Object)
                parameters.Add("password", Password)
                parameters.Add("pages", Pages)
                parameters.Add("url", uploadedFileUrl)
                parameters.Add("searchString", SearchString)
                parameters.Add("regexSearch", RegexSearch)
                parameters.Add("async", Async)

                ' Convert dictionary of params to JSON
                Dim jsonPayload As String = JsonConvert.SerializeObject(parameters)

                ' Execute POST request with JSON payload
                response = webClient.UploadString(url, jsonPayload)

                ' Parse JSON response
                json = JObject.Parse(response)

                If json("error").ToObject(Of Boolean) = False Then

                    ' Asynchronous job ID
                    Dim jobId = json("jobId").ToString()

                    ' URL of generated json file that will available after the job completion
                    Dim resultFileUrl = json("url").ToString()

                    ' Check the job status in a loop. 
                    ' If you don't want to pause the main thread you can rework the code 
                    ' to use a separate thread for the status checking And completion.
                    Do
                        Dim status = CheckJobStatus(jobId) ' Possible statuses: "working", "failed", "aborted", "success".

                        ' Display timestamp and status (for demo purpose)
                        Console.WriteLine(DateTime.Now.ToLongTimeString() + ": " + status)

                        If (status = "success") Then
                            ' Execute request
                            Dim respFileJson As String = webClient.DownloadString(resultFileUrl)

                            ' Parse JSON response
                            Dim jsonFoundInformation As JArray = JArray.Parse(respFileJson)

                            ' Display found information in console
                            For Each item As JToken In jsonFoundInformation
                                Console.WriteLine($"Found text {item("text")} at coordinates {item("left")}, {item("top")}")
                            Next

                            Exit Do
                        ElseIf (status = "working") Then
                            ' Pause for a few seconds
                            Thread.Sleep(3000)
                        Else
                            Console.WriteLine(status)
                            Exit Do
                        End If
                    Loop

                Else
                    Console.WriteLine(json("message").ToString())
                End If

            End If

        Catch ex As WebException
            Console.WriteLine(ex.ToString())
        End Try

        webClient.Dispose()

        Console.WriteLine()
        Console.WriteLine("Press any key...")
        Console.ReadKey()

    End Sub

    Function CheckJobStatus(ByVal jobId As String)

        Using webClient As New WebClient

            ' Set API Key
            webClient.Headers.Add("x-api-key", API_KEY)

            Dim url As String = "https://api.pdf.co/v1/job/check?jobid=" & jobId

            Dim response As String = webClient.DownloadString(url)
            Dim json As JObject = JObject.Parse(response)

            Return Convert.ToString(json("status"))

        End Using

    End Function

End Module