#!/usr/bin/env pwsh
<#
.SYNOPSIS
    Verifies the Module 03 challenge solution (checkpoint-aware).

.DESCRIPTION
    This script can verify completion of individual checkpoints or
    the entire module. Without arguments, it verifies all checkpoints.

.PARAMETER Checkpoint
    The checkpoint to verify: start, merge, or merge-conflict.
    If not specified, verifies all checkpoints.

.EXAMPLE
    .\verify.ps1
    Verifies all three checkpoints are complete.

.EXAMPLE
    .\verify.ps1 start
    Verifies only the branching basics checkpoint.

.EXAMPLE
    .\verify.ps1 merge
    Verifies only the merging checkpoint.
#>

param(
    [ValidateSet('start', 'merge', 'merge-conflict', '')]
    [string]$Checkpoint = ''
)

$script:allChecksPassed = $true

# ============================================================================
# Helper Functions
# ============================================================================

function Write-Pass {
    param([string]$Message)
    Write-Host "[PASS] $Message" -ForegroundColor Green
}

function Write-Fail {
    param([string]$Message)
    Write-Host "[FAIL] $Message" -ForegroundColor Red
    $script:allChecksPassed = $false
}

function Write-Hint {
    param([string]$Message)
    Write-Host "[HINT] $Message" -ForegroundColor Yellow
}

# ============================================================================
# Checkpoint 1: Branching Basics Verification
# ============================================================================

function Verify-Branching {
    Write-Host "`n=== Checkpoint 1: Branching Basics ===" -ForegroundColor Cyan

    # Save current branch
    $originalBranch = git branch --show-current 2>$null

    # Check if feature-login branch exists
    $branchExists = git branch --list "feature-login" 2>$null
    if ($branchExists) {
        Write-Pass "Branch 'feature-login' exists"
    } else {
        Write-Fail "Branch 'feature-login' not found"
        Write-Hint "Create the branch with: git switch -c feature-login"
        return
    }

    # Check if feature-login has commits beyond main (or if they've been merged)
    $commitCount = git rev-list main..feature-login --count 2>$null
    $mergeCommitExists = (git log --merges --oneline 2>$null | Select-String "Merge.*feature-login")

    if ($mergeCommitExists -and $commitCount -eq 0) {
        # Commits were merged into main - this is correct!
        Write-Pass "Branch 'feature-login' commits have been merged into main"
    } elseif ($commitCount -ge 2) {
        Write-Pass "Branch 'feature-login' has $commitCount new commits"
    } else {
        Write-Fail "Branch 'feature-login' needs at least 2 new commits (found: $commitCount)"
        Write-Hint "Make sure you've committed login.py and made at least one more commit"
    }

    # Switch to feature-login and check for login.py
    git switch feature-login 2>$null | Out-Null
    if (Test-Path "login.py") {
        Write-Pass "File 'login.py' exists in feature-login branch"
    } else {
        Write-Fail "File 'login.py' not found in feature-login branch"
        Write-Hint "Create login.py and commit it to the feature-login branch"
    }

    # Switch to main and verify login.py doesn't exist there yet (unless merged)
    git switch main 2>$null | Out-Null

    # Check if merge happened - if so, login.py can exist on main
    $mergeCommitExists = (git log --merges --oneline 2>$null | Select-String "Merge.*feature-login")

    if (-not $mergeCommitExists) {
        # No merge yet - login.py should NOT be on main
        if (-not (Test-Path "login.py")) {
            Write-Pass "File 'login.py' does NOT exist in main branch (branches are independent!)"
        } else {
            Write-Fail "File 'login.py' should not exist in main branch yet (before merge)"
            Write-Hint "Make sure you created login.py only on the feature-login branch"
        }
    }

    # Switch back to original branch
    if ($originalBranch) {
        git switch $originalBranch 2>$null | Out-Null
    }
}

# ============================================================================
# Checkpoint 2: Merging Verification
# ============================================================================

function Verify-Merging {
    Write-Host "`n=== Checkpoint 2: Merging Branches ===" -ForegroundColor Cyan

    # Check current branch is main
    $currentBranch = git branch --show-current 2>$null
    if ($currentBranch -eq "main") {
        Write-Pass "Currently on main branch"
    } else {
        Write-Fail "Should be on main branch (currently on: $currentBranch)"
        Write-Hint "Switch to main with: git switch main"
    }

    # Check if login.py exists on main (indicates merge happened)
    if (Test-Path "login.py") {
        Write-Pass "File 'login.py' exists on main branch (merged successfully)"
    } else {
        Write-Fail "File 'login.py' not found on main branch"
        Write-Hint "Merge feature-login into main with: git merge feature-login"
    }

    # Check for merge commit
    $mergeCommitExists = (git log --merges --oneline 2>$null | Select-String "Merge.*feature-login")

    if ($mergeCommitExists) {
        Write-Pass "Merge commit exists"
    } else {
        Write-Fail "No merge commit found"
        Write-Hint "Create a merge commit with: git merge feature-login"
    }

    # Check commit count (should have both branches' commits)
    $commitCount = [int](git rev-list --count HEAD 2>$null)
    if ($commitCount -ge 6) {
        Write-Pass "Repository has $commitCount commits (merge complete)"
    } else {
        Write-Fail "Repository should have at least 6 commits after merge (found: $commitCount)"
    }
}

# ============================================================================
# Checkpoint 3: Merge Conflicts Verification
# ============================================================================

function Verify-MergeConflicts {
    Write-Host "`n=== Checkpoint 3: Resolving Merge Conflicts ===" -ForegroundColor Cyan

    # Check current branch is main
    $currentBranch = git branch --show-current 2>$null
    if ($currentBranch -eq "main") {
        Write-Pass "Currently on main branch"
    } else {
        Write-Fail "Should be on main branch (currently on: $currentBranch)"
        Write-Hint "Switch to main with: git switch main"
    }

    # Check that merge is not in progress
    if (Test-Path ".git/MERGE_HEAD") {
        Write-Fail "Merge is still in progress (conflicts not resolved)"
        Write-Hint "Resolve conflicts in config.json, then: git add config.json && git commit"
        return
    } else {
        Write-Pass "No merge in progress (conflicts resolved)"
    }

    # Check if config.json exists
    if (Test-Path "config.json") {
        Write-Pass "File 'config.json' exists"
    } else {
        Write-Fail "File 'config.json' not found"
        Write-Hint "Merge update-config branch with: git merge update-config"
        return
    }

    # Verify config.json is valid JSON
    try {
        $configContent = Get-Content "config.json" -Raw
        $config = $configContent | ConvertFrom-Json -ErrorAction Stop
        Write-Pass "File 'config.json' is valid JSON"
    } catch {
        Write-Fail "File 'config.json' is not valid JSON"
        Write-Hint "Make sure you removed all conflict markers (<<<<<<<, =======, >>>>>>>)"
        return
    }

    # Check for conflict markers
    if ($configContent -match '<<<<<<<|=======|>>>>>>>') {
        Write-Fail "Conflict markers still present in config.json"
        Write-Hint "Remove all conflict markers (<<<<<<<, =======, >>>>>>>)"
        return
    } else {
        Write-Pass "No conflict markers in config.json"
    }

    # Verify both settings are present (timeout and debug)
    if ($config.app.timeout -eq 5000) {
        Write-Pass "Timeout setting preserved (5000)"
    } else {
        Write-Fail "Timeout setting missing or incorrect"
        Write-Hint "Keep the timeout: 5000 setting from main branch"
    }

    if ($config.app.debug -eq $true) {
        Write-Pass "Debug setting preserved (true)"
    } else {
        Write-Fail "Debug setting missing or incorrect"
        Write-Hint "Keep the debug: true setting from update-config branch"
    }

    # Verify merge commit exists for update-config
    $updateConfigMerge = (git log --merges --oneline 2>$null | Select-String "Merge.*update-config")
    if ($updateConfigMerge) {
        Write-Pass "Merge commit exists for update-config branch"
    } else {
        Write-Fail "No merge commit found for update-config"
        Write-Hint "Complete the merge with: git commit (after resolving conflicts)"
    }
}

# ============================================================================
# Main Script Logic
# ============================================================================

# Check if challenge directory exists
if (-not (Test-Path "challenge")) {
    Write-Host "[ERROR] Challenge directory not found." -ForegroundColor Red
    Write-Host "Run .\setup.ps1 first to create the challenge environment." -ForegroundColor Yellow
    exit 1
}

Push-Location "challenge"

# Check if git repository exists
if (-not (Test-Path ".git")) {
    Write-Host "[ERROR] Not a git repository." -ForegroundColor Red
    Write-Host "Run ..\setup.ps1 first to create the challenge environment." -ForegroundColor Yellow
    Pop-Location
    exit 1
}

# Run appropriate verification
if ($Checkpoint -eq '') {
    # Verify all checkpoints
    Write-Host "`n=== Verifying All Checkpoints ===" -ForegroundColor Cyan

    Verify-Branching
    Verify-Merging
    Verify-MergeConflicts

} else {
    # Verify specific checkpoint
    switch ($Checkpoint) {
        'start' { Verify-Branching }
        'merge' { Verify-Merging }
        'merge-conflict' { Verify-MergeConflicts }
    }
}

Pop-Location

# Final summary
Write-Host ""
if ($script:allChecksPassed) {
    Write-Host "=========================================" -ForegroundColor Green
    Write-Host "   CONGRATULATIONS! CHALLENGE PASSED!" -ForegroundColor Green
    Write-Host "=========================================" -ForegroundColor Green

    if ($Checkpoint -eq '') {
        Write-Host "`nYou've completed the entire module!" -ForegroundColor Cyan
        Write-Host "You've mastered:" -ForegroundColor Cyan
        Write-Host "  ✓ Creating and working with branches" -ForegroundColor White
        Write-Host "  ✓ Merging branches together" -ForegroundColor White
        Write-Host "  ✓ Resolving merge conflicts" -ForegroundColor White
        Write-Host "`nReady for the next module!" -ForegroundColor Green
    } else {
        Write-Host "`nCheckpoint '$Checkpoint' complete!" -ForegroundColor Cyan

        switch ($Checkpoint) {
            'start' {
                Write-Host "Next: Move to the merging checkpoint" -ForegroundColor White
                Write-Host "  ..\reset.ps1 merge  OR  continue to merge feature-login" -ForegroundColor Yellow
            }
            'merge' {
                Write-Host "Next: Move to the conflict resolution checkpoint" -ForegroundColor White
                Write-Host "  ..\reset.ps1 merge-conflict" -ForegroundColor Yellow
            }
            'merge-conflict' {
                Write-Host "Module complete! Ready for the next module!" -ForegroundColor Green
            }
        }
    }
    Write-Host ""
    exit 0
} else {
    Write-Host "[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 ""
    exit 1
}