[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
Add-Type -AssemblyName System.Web

$utf8NoBom = New-Object System.Text.UTF8Encoding($false)

$BaseUrl   = 'https://fukuchiyama-web.campusplan.jp/portal/'
$StartDate = '2025-09-22'
$EndDate   = '2025-12-31'
$ApiUrl    = 'https://www.48v.me/~7kasone/cgi-bin/zemi_course_take_list.py'

function ConvertFrom-SecureStringToPlain {
    param([Parameter(Mandatory=$true)][Security.SecureString]$SecureString)
    $bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($SecureString)
    try { [Runtime.InteropServices.Marshal]::PtrToStringAuto($bstr) } finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
}

function Get-UserConfirmation {
    $title = "Execution Confirmation"
    $message = "This script will access the portal and send data to external API. Continue?"
    $yes = New-Object System.Management.Automation.Host.ChoiceDescription "&Yes", "Continue execution"
    $no  = New-Object System.Management.Automation.Host.ChoiceDescription "&No",  "Cancel execution"
    $opts = [System.Management.Automation.Host.ChoiceDescription[]]($yes, $no)
    return $host.UI.PromptForChoice($title, $message, $opts, 1) -eq 0
}

function Write-Progress-Info { param([string]$Activity,[string]$Status) Write-Progress -Activity $Activity -Status $Status }

function Get-VerificationToken {
    param([string]$Html)
    $patterns = @(
        '<input[^>]*name=["'']__RequestVerificationToken["''][^>]*value=["'']([^"'']+)["''][^>]*>',
        '<input[^>]*value=["'']([^"'']+)["''][^>]*name=["'']__RequestVerificationToken["''][^>]*>'
    )
    foreach ($p in $patterns) { if ($Html -match $p) { return $Matches[1] } }
    throw "RequestVerificationToken not found"
}

function Get-ClientTokenId {
    param([string]$Html)
    if ($Html -match 'var\s+_ClientTokenId\s*=\s*["'']([^"'']+)["'']') { return $Matches[1] }
    throw "ClientTokenId not found"
}

function Get-AccessToken {
    param([Microsoft.PowerShell.Commands.WebRequestSession]$Session,[string]$BaseUrl,[string]$ClientTokenId)
    $authorizeUri = "$BaseUrl" + "Account/Authorize?client_id=$ClientTokenId&response_type=token&state="
    $resp = Invoke-WebRequest -Uri $authorizeUri -WebSession $Session
    $frag = $resp.BaseResponse.ResponseUri.Fragment.TrimStart('#')
    $qs   = [System.Web.HttpUtility]::ParseQueryString('?' + $frag)
    $tok  = $qs['access_token']
    if (-not $tok) { throw "Access token not found" }
    return $tok
}

function Get-CampusCalendarData {
    param([Microsoft.PowerShell.Commands.WebRequestSession]$Session,[string]$BaseUrl,[string]$AccessToken,[string]$Start,[string]$End)
    $headers = @{ 'Content-Type' = 'application/json; charset=utf-8'; 'X-CPAuthorize' = "Bearer $AccessToken" }
    $apiUri  = "$BaseUrl" + "api/KogiCalendar/?uKbn=1&start=$Start&end=$End"
    Invoke-RestMethod -Uri $apiUri -Headers $headers -WebSession $Session -Method GET
}

function Show-CalendarSummary {
    param([array]$CalendarData)
    Write-Host "Calendar Data Summary:" -ForegroundColor Green
    Write-Host ("Total entries: {0}" -f $CalendarData.Count) -ForegroundColor Yellow
    if ($CalendarData.Count -gt 0) {
        Write-Host "Sample entries:" -ForegroundColor Yellow
        $CalendarData[0..([Math]::Min(2, $CalendarData.Count - 1))] | ForEach-Object {
            Write-Host ("  - {0} [{1} - {2}]" -f $_.title, $_.start, $_.end) -ForegroundColor Cyan
        }
    }
}

function Send-DataToApi {
    param([string]$Email,[object]$Data,[string]$ApiUrl)
    $uri      = "$ApiUrl" + "?email=$([System.Web.HttpUtility]::UrlEncode($Email))"
    $jsonData = $Data | ConvertTo-Json -Depth 8 -Compress
    $utf8Bytes = $utf8NoBom.GetBytes($jsonData)

    $req = [System.Net.HttpWebRequest]::Create($uri)
    $req.Method = "POST"
    $req.ContentType = "application/json; charset=utf-8"
    $req.ContentLength = $utf8Bytes.Length
    $req.UserAgent = "PowerShell/UTF8-Client"

    try {
        $rs = $req.GetRequestStream(); $rs.Write($utf8Bytes, 0, $utf8Bytes.Length); $rs.Close()
        $resp = $req.GetResponse()
        $stream = $resp.GetResponseStream()
        $reader = [System.IO.StreamReader]::new($stream, [System.Text.Encoding]::UTF8)
        $content = $reader.ReadToEnd()
        $reader.Close(); $resp.Close()
        $content | ConvertFrom-Json
    } catch {
        throw "API request failed: $($_.Exception.Message)"
    }
}

try {
    if (-not (Get-UserConfirmation)) { Write-Host "Execution cancelled by user." -ForegroundColor Red; return }

    $secureUsername = Read-Host -AsSecureString -Prompt 'Username'
    $securePassword = Read-Host -AsSecureString -Prompt 'Password'
    $username = ConvertFrom-SecureStringToPlain -SecureString $secureUsername
    $password = ConvertFrom-SecureStringToPlain -SecureString $securePassword
    $email = "$username@fukuchiyama.ac.jp"

    Write-Progress-Info "Portal Login" "Accessing login page"
    $loginPage = Invoke-WebRequest -Uri ($BaseUrl + 'Account/Login') -SessionVariable session
    $verificationToken = Get-VerificationToken -Html $loginPage.Content

    Write-Progress-Info "Portal Login" "Submitting credentials"
    $loginBody = @{ Username = $username; Password = $password; __RequestVerificationToken = $verificationToken }
    $null = Invoke-WebRequest -Uri ($BaseUrl + 'Account/Login') -WebSession $session -Method POST -ContentType 'application/x-www-form-urlencoded' -Body $loginBody

    Write-Progress-Info "Token Extraction" "Getting client token"
    $portal = Invoke-WebRequest -Uri $BaseUrl -WebSession $session
    $clientTokenId = Get-ClientTokenId -Html $portal.Content

    Write-Progress-Info "Authorization" "Getting access token"
    $accessToken = Get-AccessToken -Session $session -BaseUrl $BaseUrl -ClientTokenId $clientTokenId

    Write-Progress-Info "Data Retrieval" "Fetching calendar data"
    $calendarData = Get-CampusCalendarData -Session $session -BaseUrl $BaseUrl -AccessToken $accessToken -Start $StartDate -End $EndDate

    Show-CalendarSummary -CalendarData $calendarData

    Write-Progress-Info "API Submission" "Sending data to external API"
    $apiResponse = Send-DataToApi -Email $email -Data $calendarData -ApiUrl $ApiUrl

    Write-Host "API Response:" -ForegroundColor Green
    $apiResponse | ConvertTo-Json -Depth 3 | Write-Host -ForegroundColor Cyan

    Write-Host "Process completed successfully." -ForegroundColor Green
} catch {
    Write-Host ("Error: {0}" -f $_.Exception.Message) -ForegroundColor Red
    Write-Host ("Stack Trace: {0}" -f $_.ScriptStackTrace) -ForegroundColor Yellow
    return
} finally {
    Write-Progress -Completed -Activity "Complete"
}