How to use powerShell and regular expressions to parse a text file - regex

Question

I am new to powerShell and need to input a text file, parse it to extract the data we need and write the result to a .csv file. However, at this point I still am unable to parse the file and am totally confused about which PS commands to use and how to incorporate regular expressions. While I could write out all of the ways I've tried to get this to work I think it would be more beneficial to just ask for help and then ask questions on anything I don't fully understand. FYI: we're running Win10 and my only 2 scripting options are batch or PowerShell.
We have a JSON file that was formatted by notepad++ and looks like this:
"issue": [{
"field": [{
"name": "someName",
"value": [],
"values": []
}],
"field": [{
"name": "numberinproject",
"value": ["81"],
"values": ["81"]
}],
"field": [{
"name": "summary",
"value": ["This is a summary for 81."],
"values": ["This is a summary for 81."]
}],
"comment":[{
"text": "someText for 81 - 01",
"markdown":false,
"created":0123456789101,
"updated":null,
"Author":"first.last01",
"permitted group":null
},{
"text": "someText for 81 - 02",
"markdown":false,
"created":0123456789102,
"updated":null,
"Author":"first.last02",
"permitted group":null
},{
"text": "someText for 81 - 03",
"markdown":false,
"created":0123456789103,
"updated":null,
"Author":"first.last03",
"permitted group":null
}],
"field": [{
"name": "someNameTwo",
"value": [],
"values": []
}],
"field": [{
"name": "numberinproject",
"value": ["83"],
"values": ["83"]
}],
"field": [{
"name": "summary",
"value": ["This is a summary for 83."],
"values": ["This is a summary for 83."]
}],
"comment":[]
}
]
What I am attempting to do is extract the numberinproject, summary and Comment text, created and Author.
Notice that there could be Zero to multiple comments per project number. The comment.created field is a 13 digit epoch number that has to be converted into mm/dd/yyyy hh:mm:ss AM/PM
I had hoped to export this data into a .csv file but at this time would be happy just getting the data parsed out of the file.
Thanks for whatever feedback you can give.
===================================================
By request: Here are some of the things I tried and I apologise for this being such a mess. Since the "json" file was not in a format that convertfrom-json could use I assumed the file was actually text and that is where this starts.
What I've picked up has been from Searching on the web. If anyone can suggest a good article, please let me know and I will read it.
Set-Variable -Name "inputFile" -Value "inputFile.txt"
Set-Variable -Name "outputTXTFile" -Value "outputTXTFile.txt"
Set-Variable -Name "outputFile" -Value "outputFile.csv"
numberinProject = \"value\"\:\s\[\"\d+
summary = \"value\"\:\s\[\".+\"\],
comment - text = \"text\"\:\s\".+\",
comment - created = \"created\"\:\d{13}
comment - author = \"Author\"\:\"\w+\.\w+
## This actually worked. Though it grabbed the whole line, my plan was to then parse it a for a substring.
$results = Get-Content -Path $inputFile | Select-String -Pattern '"values": ' -CaseSensitive -SimpleMatch
# ------------------------------------------------
# However, If I tried using regex, the parse failed
$results = Get-Content -Path $inputFile | Select-String -Pattern \"values\"\:\s\[\"\d+ -CaseSensitive -SimpleMatch
# I also tried this
#$A = Get-ChildItem $inputFile | Select-String -Pattern '(<ID>\"value\"\:\s\[\"\d'
# $results | Export-CSV $outputFile -NoTypeInformation
$results | Out-File $outputTXTFile
# ---------------------------------------------------------
#I tried to output the file as a single string for manipulation - it didn't work
Get-Content -Path $inputFile) -join "`r`n" | Out-File $outputTXTFile
# I tried to use "patterns" to find the data but that didn't work
$issueIDPattern = "(<ID>\"value\"\:\s\[\"\d+)"
$summaryPattern = "\"value\"\:\s\[\".+\"\],"
$commentTextPattern = "\"text\"\:\s\".+\","
$commentDatePattern = "\"created\"\:\d{13}"
$commentAuthorPattern = "\"Author\"\:\"\w+\.\w+
Get-ChildItem $inputFile|
Select-String -Pattern $issueIDPattern |
Foreach-Object {
$ID = $_.Matches[0].Groups['ID'].Value
[PSCustomObject] #{
issueNum = $ID
}
}
### Also tried a variation of this
Get-Content C:\Path\To\File.txt) -join "`r`n" -Split "(?m)^(?=\S)" |
Where{$_} |
ForEach{
Clear-Variable commentauthor,commentcreated,commenttext,summary,numberinProject
$commentcreated = #()
$numberinProject = ($_ -split "`r`n")[0].trim()
Switch -regex ($_ -split "`r`n"){
"^\s+summary:" {$summary = ($_ -split ':',2)[-1].trim();Continue}
"^\s+.:\\" {$commentcreated += $_.trim();continue}
"^\s+commenttext" {$commenttext = [RegEx]::Matches($_,"(?<=commenttext installed from )(.+?)(?= \[)").value;continue}
}
[PSCustomObject]#{'numberinProject' = $numberinProject;'summary' = $summary; 'commenttext' = $commenttext; 'commentcreated' = $commentcreated}
}