#!/usr/bin/env pwsh
<#
.SYNOPSIS
    Verifies the Module 06 challenge solution.

.DESCRIPTION
    This script checks that:
    - The challenge directory exists
    - A Git repository exists
    - All three feature branches have been merged
    - Appropriate merge strategies were used
    - Student understands the difference between fast-forward and three-way merges
#>

Write-Host "`n=== Verifying Module 06 Solution ===" -ForegroundColor Cyan

$allChecksPassed = $true

# Check if challenge directory exists
if (-not (Test-Path "challenge")) {
    Write-Host "[FAIL] Challenge directory not found. Did you run setup.ps1?" -ForegroundColor Red
    exit 1
}

Set-Location "challenge"

# Check if git repository exists
if (-not (Test-Path ".git")) {
    Write-Host "[FAIL] Not a git repository. Did you run setup.ps1?" -ForegroundColor Red
    Set-Location ..
    exit 1
}

# Check current branch is main
$currentBranch = git branch --show-current 2>$null
if ($currentBranch -eq "main") {
    Write-Host "[PASS] Currently on main branch" -ForegroundColor Green
} else {
    Write-Host "[FAIL] Not on main branch (currently on: $currentBranch)" -ForegroundColor Red
    Write-Host "[HINT] Switch to main with: git switch main" -ForegroundColor Yellow
    $allChecksPassed = $false
}

# Check 1: Fast-Forward Merge - utils.py should exist
if (Test-Path "utils.py") {
    Write-Host "[PASS] utils.py exists (feature-fast-forward merged)" -ForegroundColor Green
} else {
    Write-Host "[FAIL] utils.py not found" -ForegroundColor Red
    Write-Host "[HINT] Merge feature-fast-forward: git merge feature-fast-forward" -ForegroundColor Yellow
    $allChecksPassed = $false
}

# Check 2: Three-Way Merge - auth.py should exist
if (Test-Path "auth.py") {
    Write-Host "[PASS] auth.py exists (feature-divergent merged)" -ForegroundColor Green
} else {
    Write-Host "[FAIL] auth.py not found" -ForegroundColor Red
    Write-Host "[HINT] Merge feature-divergent: git merge feature-divergent" -ForegroundColor Yellow
    $allChecksPassed = $false
}

# Check 3: --no-ff Merge - config.py should exist
if (Test-Path "config.py") {
    Write-Host "[PASS] config.py exists (feature-optional merged)" -ForegroundColor Green
} else {
    Write-Host "[FAIL] config.py not found" -ForegroundColor Red
    Write-Host "[HINT] Merge feature-optional: git merge --no-ff feature-optional" -ForegroundColor Yellow
    $allChecksPassed = $false
}

# Check for merge commits
$mergeCommits = git log --merges --oneline 2>$null
$mergeCount = ($mergeCommits | Measure-Object -Line).Lines

if ($mergeCount -ge 2) {
    Write-Host "[PASS] Found $mergeCount merge commit(s)" -ForegroundColor Green
    Write-Host "[INFO] Expected: 1 from three-way merge + 1 from --no-ff = 2 total" -ForegroundColor Cyan
} else {
    Write-Host "[FAIL] Only found $mergeCount merge commit(s), expected at least 2" -ForegroundColor Red
    Write-Host "[HINT] Make sure to:" -ForegroundColor Yellow
    Write-Host "       1. Merge feature-divergent (creates merge commit)" -ForegroundColor Yellow
    Write-Host "       2. Merge feature-optional with --no-ff flag (forces merge commit)" -ForegroundColor Yellow
    $allChecksPassed = $false
}

# Provide detailed merge analysis
Write-Host "`n--- Merge Analysis ---" -ForegroundColor Cyan

# Count total commits
$totalCommits = git rev-list --count HEAD 2>$null
Write-Host "[INFO] Total commits on main: $totalCommits" -ForegroundColor Cyan

# List merge commits
if ($mergeCommits) {
    Write-Host "[INFO] Merge commits found:" -ForegroundColor Cyan
    $mergeCommits | ForEach-Object {
        Write-Host "       $_" -ForegroundColor White
    }
}

# Check if branches still exist
$branches = git branch 2>$null
Write-Host "[INFO] Existing branches:" -ForegroundColor Cyan
$branches | ForEach-Object {
    Write-Host "       $_" -ForegroundColor White
}

Set-Location ..

# Final summary
if ($allChecksPassed) {
    Write-Host "`n" -NoNewline
    Write-Host "=====================================" -ForegroundColor Green
    Write-Host "   CONGRATULATIONS! CHALLENGE PASSED!" -ForegroundColor Green
    Write-Host "=====================================" -ForegroundColor Green
    Write-Host "`nYou've mastered Git merge strategies!" -ForegroundColor Cyan
    Write-Host "`nYou now understand:" -ForegroundColor Cyan
    Write-Host "  - Fast-forward merges (linear history, no merge commit)" -ForegroundColor White
    Write-Host "  - Three-way merges (divergent branches, creates merge commit)" -ForegroundColor White
    Write-Host "  - How to force merge commits with --no-ff flag" -ForegroundColor White
    Write-Host "  - When to use each merge strategy" -ForegroundColor White
    Write-Host "  - Trade-offs between linear and branched history" -ForegroundColor White
    Write-Host "`nKey Takeaways:" -ForegroundColor Yellow
    Write-Host "  - Git chooses the strategy automatically based on branch state" -ForegroundColor Cyan
    Write-Host "  - Use --no-ff to preserve feature branch history" -ForegroundColor Cyan
    Write-Host "  - Use --ff-only to enforce linear history" -ForegroundColor Cyan
    Write-Host "  - Different workflows prefer different strategies" -ForegroundColor Cyan
    Write-Host "`nNow you can make informed decisions about merge strategies for your projects!" -ForegroundColor Green
    Write-Host ""
} else {
    Write-Host "`n[SUMMARY] Some checks failed. Review the hints above and try again." -ForegroundColor Red
    Write-Host "[INFO] You can run this verification script as many times as needed." -ForegroundColor Yellow
    Write-Host ""
    Write-Host "Quick Reference:" -ForegroundColor Cyan
    Write-Host "  git merge feature-fast-forward          # Fast-forward merge" -ForegroundColor White
    Write-Host "  git merge feature-divergent             # Three-way merge" -ForegroundColor White
    Write-Host "  git merge --no-ff feature-optional      # Force merge commit" -ForegroundColor White
    Write-Host ""
    exit 1
}