#!/usr/bin/env bash
#
# Build Architecture Guard Script
# 
# Author: Matthew Raymer
# Date: 2025-08-20
# Purpose: Protects build-critical files by requiring BUILDING.md updates
#
# Usage:
#   ./scripts/build-arch-guard.sh --staged     # Check staged files (pre-commit)
#   ./scripts/build-arch-guard.sh --range      # Check range (pre-push)
#   ./scripts/build-arch-guard.sh              # Check working directory
#

set -euo pipefail

# Sensitive paths that require BUILDING.md updates when modified
SENSITIVE=(
  "vite.config.*" 
  "scripts/**" 
  "electron/**" 
  "android/**" 
  "ios/**"
  "sw_scripts/**" 
  "sw_combine.js" 
  "Dockerfile" 
  "docker/**"
  "capacitor.config.ts"
  "package.json"
  "package-lock.json"
  "yarn.lock"
  "pnpm-lock.yaml"
)

# Documentation files that must be updated alongside sensitive changes
DOCS_REQUIRED=("BUILDING.md")

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

log_info() {
    echo -e "${BLUE}[guard]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[guard]${NC} $1"
}

log_error() {
    echo -e "${RED}[guard]${NC} $1"
}

log_success() {
    echo -e "${GREEN}[guard]${NC} $1"
}

# Collect files based on mode
collect_files() {
    if [[ "${1:-}" == "--staged" ]]; then
        # Pre-commit: check staged files
        git diff --name-only --cached
    elif [[ "${1:-}" == "--range" ]]; then
        # Pre-push: check commits being pushed
        RANGE="${2:-HEAD~1..HEAD}"
        git diff --name-only "$RANGE"
    else
        # Default: check working directory changes
        git diff --name-only HEAD
    fi
}

# Check if a file matches any sensitive pattern
matches_sensitive() {
    local f="$1"
    for pat in "${SENSITIVE[@]}"; do
        # Convert glob pattern to regex
        local rx="^${pat//\./\.}$"
        rx="${rx//\*\*/.*}"
        rx="${rx//\*/[^/]*}"
        
        if [[ "$f" =~ $rx ]]; then
            return 0
        fi
    done
    return 1
}

# Check if documentation was updated
check_docs_updated() {
    local changed_files=("$@")
    
    for changed_file in "${changed_files[@]}"; do
        for required_doc in "${DOCS_REQUIRED[@]}"; do
            if [[ "$changed_file" == "$required_doc" ]]; then
                return 0
            fi
        done
    done
    return 1
}

# Main guard logic
main() {
    local mode="${1:-}"
    local arg="${2:-}"
    
    log_info "Running Build Architecture Guard..."
    
    # Collect changed files
    mapfile -t changed_files < <(collect_files "$mode" "$arg")
    
    if [[ ${#changed_files[@]} -eq 0 ]]; then
        log_info "No files changed, guard check passed"
        exit 0
    fi
    
    log_info "Checking ${#changed_files[@]} changed files..."
    
    # Find sensitive files that were touched
    sensitive_touched=()
    for file in "${changed_files[@]}"; do
        if matches_sensitive "$file"; then
            sensitive_touched+=("$file")
        fi
    done
    
    # If no sensitive files were touched, allow the change
    if [[ ${#sensitive_touched[@]} -eq 0 ]]; then
        log_success "No build-sensitive files changed, guard check passed"
        exit 0
    fi
    
    # Sensitive files were touched, log them
    log_warn "Build-sensitive paths changed:"
    for file in "${sensitive_touched[@]}"; do
        echo "  - $file"
    done
    
    # Check if required documentation was updated
    if check_docs_updated "${changed_files[@]}"; then
        log_success "BUILDING.md updated alongside build changes, guard check passed"
        exit 0
    else
        log_error "Build-sensitive files changed but BUILDING.md was not updated!"
        echo
        echo "The following build-sensitive files were modified:"
        for file in "${sensitive_touched[@]}"; do
            echo "  - $file"
        done
        echo
        echo "When modifying build-critical files, you must also update BUILDING.md"
        echo "to document any changes to the build process."
        echo
        echo "Please:"
        echo "  1. Update BUILDING.md with relevant changes"
        echo "  2. Stage the BUILDING.md changes: git add BUILDING.md"
        echo "  3. Retry your commit/push"
        echo
        exit 2
    fi
}

# Handle help flag
if [[ "${1:-}" =~ ^(-h|--help)$ ]]; then
    echo "Build Architecture Guard Script"
    echo
    echo "Usage:"
    echo "  $0 [--staged|--range [RANGE]]"
    echo
    echo "Options:"
    echo "  --staged          Check staged files (for pre-commit hook)"
    echo "  --range [RANGE]   Check git range (for pre-push hook)"
    echo "                    Default range: HEAD~1..HEAD"
    echo "  (no args)         Check working directory changes"
    echo
    echo "Examples:"
    echo "  $0 --staged                    # Pre-commit check"
    echo "  $0 --range origin/main..HEAD   # Pre-push check"
    echo "  $0                             # Working directory check"
    exit 0
fi

main "$@"