#!pwsh

[CmdletBinding()]
param(
    [Parameter(Mandatory = $true, Position = 0)]
    [string]$problemId
)

begin
{
    $ErrorActionPreference = 'Stop'
}

end
{
    Write-Host "Try to fetch problem $($problemId)"

    $graphQuery = @'
query questionData($titleSlug: String!) {
question(titleSlug: $titleSlug) {
content
stats
codeDefinition
sampleTestCase
metaData
}
}
'@
    $response = Invoke-RestMethod -Uri "https://leetcode.cn/api/problems/algorithms/" -Method Get
    $problem = @($response.stat_status_pairs | Where-Object { $_.stat.frontend_question_id -eq $problemId })

    if ($problem.Count -ne 1)
    {
        Write-Error "Failed to find target problem $($problemId)"
    }
    $problem = $problem[0]

    $problemNumber = "{0:D4}" -f ($problem.stat.frontend_question_id -as [int])
    $filename = "$problemNumber-$($problem.stat.question__title_slug).cpp"

    $existedFile = @(Get-ChildItem ./src/problems | Where-Object { $_.Name -eq $filename})

    if ($existedFile.Count -gt 0)
    {
        Write-Error "Problem $($problem.stat.question__title_slug) has been fetched, see src/problems/$filename."
    }

    $variables = @{
        titleSlug = $problem.stat.question__title_slug
    } | ConvertTo-Json

    $query = @{
        operationName = "questionData"
        variables = $variables
        query = $graphQuery
    }

    Write-Host "Try to fetch details of $($problem.stat.question__title_slug)"
    $response = Invoke-RestMethod -Uri "https://leetcode.cn/graphql" -Body $query -Method Post

    $codeDefinition = @($response.data.question.codeDefinition | ConvertFrom-Json | Where-Object { $_.value -eq "cpp" })
    if ($codeDefinition.Count -ne 1)
    {
        Write-Error "Failed to find C++ code definition"
    }
    $testcaseName = "P$($problem.stat.frontend_question_id)"

    $outputCode = @"
/**
* [$($problem.stat.frontend_question_id)] $($problem.stat.question__title_slug)
*/
#include <gtest/gtest.h>
using namespace std;


// submission codes start here

$($codeDefinition[0].defaultCode)

// submission codes end

TEST($testcaseName, Test1)
{
}
"@

    Set-Content -Path "./src/problems/$($filename)" -Value $outputCode
    Write-Host "Saved as $filename."
}