#!/usr/bin/env pwsh

<#
.SYNOPSIS
    Verifies the bisect challenge solution.

.DESCRIPTION
    Checks that the user successfully used git bisect to find
    the commit that introduced the bug.
#>

Set-Location "challenge" -ErrorAction SilentlyContinue

# Check if challenge directory exists
if (-not (Test-Path "../verify.ps1")) {
    Write-Host "Error: Please run this script from the module directory" -ForegroundColor Red
    exit 1
}

if (-not (Test-Path ".")) {
    Write-Host "Error: Challenge directory not found. Run setup.ps1 first." -ForegroundColor Red
    Set-Location ..
    exit 1
}

Write-Host "Verifying your solution..." -ForegroundColor Cyan

# Check if git repository exists
if (-not (Test-Path ".git")) {
    Write-Host "[FAIL] No git repository found." -ForegroundColor Red
    Set-Location ..
    exit 1
}

# Make sure we're not in a bisect session
$bisectHead = Test-Path ".git/BISECT_HEAD"
if ($bisectHead) {
    Write-Host "[FAIL] You're still in a bisect session." -ForegroundColor Red
    Write-Host "Hint: End the bisect with: git bisect reset" -ForegroundColor Yellow
    Set-Location ..
    exit 1
}

# Check if bug-commit.txt exists
if (-not (Test-Path "bug-commit.txt")) {
    Write-Host "[FAIL] bug-commit.txt not found." -ForegroundColor Red
    Write-Host "Hint: After finding the bad commit, create a file with its hash:" -ForegroundColor Yellow
    Write-Host "      echo 'commit-hash' > bug-commit.txt" -ForegroundColor Yellow
    Set-Location ..
    exit 1
}

# Read the commit hash from the file
$userCommit = (Get-Content "bug-commit.txt" -Raw).Trim()

if (-not $userCommit) {
    Write-Host "[FAIL] bug-commit.txt is empty." -ForegroundColor Red
    Set-Location ..
    exit 1
}

# Get all commit hashes
$allCommits = git log --pretty=format:"%H" --reverse 2>$null
$commitArray = $allCommits -split "`n"

# The bug was introduced in commit 6 (index 5 in 0-based array)
# This is the "Refactor add function for clarity" commit
$badCommitMessage = git log --pretty=format:"%s" --grep="Refactor add function" 2>$null
$actualBadCommit = git log --pretty=format:"%H" --grep="Refactor add function" 2>$null

if (-not $actualBadCommit) {
    Write-Host "[FAIL] Could not find the expected bad commit." -ForegroundColor Red
    Write-Host "Something may be wrong with the repository setup." -ForegroundColor Yellow
    Set-Location ..
    exit 1
}

# Check if user found the correct commit
if ($userCommit -ne $actualBadCommit) {
    # Maybe they provided a short hash
    if ($actualBadCommit -like "$userCommit*") {
        Write-Host "[PASS] Correct commit identified (using short hash)!" -ForegroundColor Green
    } else {
        Write-Host "[FAIL] Incorrect commit identified." -ForegroundColor Red
        Write-Host "You identified: $userCommit" -ForegroundColor Yellow
        Write-Host "Expected: $actualBadCommit" -ForegroundColor Yellow
        Write-Host "Expected commit message: 'Refactor add function for clarity'" -ForegroundColor Yellow
        Write-Host "`nHint: Use git bisect to find where the add function broke:" -ForegroundColor Yellow
        Write-Host "  git bisect start" -ForegroundColor White
        Write-Host "  git bisect bad" -ForegroundColor White
        Write-Host "  git bisect good HEAD~10" -ForegroundColor White
        Write-Host "  # Then test with: node test.py" -ForegroundColor White
        Write-Host "  git bisect good  # or bad" -ForegroundColor White
        Set-Location ..
        exit 1
    }
} else {
    Write-Host "[PASS] Correct commit identified!" -ForegroundColor Green
}

# Verify the commit actually has the bug
git checkout $actualBadCommit 2>$null | Out-Null
$calcContent = Get-Content "calculator.py" -Raw

if ($calcContent -notmatch "add\(a, b\)[\s\S]*?return a - b") {
    Write-Host "[WARNING] The identified commit doesn't seem to have the expected bug." -ForegroundColor Yellow
}

# Return to latest commit
git checkout $(git branch --show-current 2>$null) 2>$null | Out-Null
if (-not $?) {
    git checkout main 2>$null | Out-Null
}

# Success!
Write-Host "`n========================================" -ForegroundColor Green
Write-Host "SUCCESS! Challenge completed!" -ForegroundColor Green
Write-Host "========================================" -ForegroundColor Green
Write-Host "`nYou have successfully:" -ForegroundColor Cyan
Write-Host "- Used git bisect to perform a binary search" -ForegroundColor White
Write-Host "- Tested commits systematically" -ForegroundColor White
Write-Host "- Identified the exact commit that introduced the bug" -ForegroundColor White
Write-Host "- Found: '$badCommitMessage'" -ForegroundColor White
Write-Host "`nThe bug was in commit 6 out of 10 commits." -ForegroundColor Yellow
Write-Host "Manual checking: up to 10 tests" -ForegroundColor Yellow
Write-Host "With bisect: only ~4 tests needed!" -ForegroundColor Green
Write-Host "`nYou now understand git bisect!" -ForegroundColor Green
Write-Host "`nKey takeaway:" -ForegroundColor Yellow
Write-Host "Bisect uses binary search to efficiently find bugs," -ForegroundColor White
Write-Host "saving massive amounts of time in large codebases.`n" -ForegroundColor White

Set-Location ..
exit 0