#!/bin/bash
# DBIS Cross-Reference Verification Script
# Automated link verification and cross-reference checking

set -e

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

# Configuration
PROJECT_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
REPORT_FILE="${PROJECT_ROOT}/CROSS_REFERENCE_VERIFICATION_REPORT.md"
BROKEN_LINKS=()
MISSING_FILES=()
INVALID_ANCHORS=()
TOTAL_LINKS=0
VALID_LINKS=0

echo "=========================================="
echo "DBIS Cross-Reference Verification"
echo "=========================================="
echo ""

# Function to extract markdown links
extract_links() {
    local file="$1"
    grep -oE '\[([^\]]+)\]\(([^)]+)\)' "$file" | while IFS= read -r link; do
        echo "$link"
    done
}

# Function to verify file link
verify_file_link() {
    local link_path="$1"
    local source_file="$2"
    local source_dir="$(dirname "$source_file")"
    
    # Handle relative paths
    if [[ "$link_path" == /* ]]; then
        # Absolute path from project root
        full_path="${PROJECT_ROOT}${link_path}"
    elif [[ "$link_path" == ../* ]]; then
        # Relative path going up
        full_path="$(cd "$source_dir" && cd "$(dirname "$link_path")" && pwd)/$(basename "$link_path")"
    else
        # Relative path in same directory
        full_path="${source_dir}/${link_path}"
    fi
    
    # Remove anchor if present
    file_path="${full_path%%#*}"
    
    if [[ -f "$file_path" ]]; then
        return 0
    else
        return 1
    fi
}

# Function to verify anchor
verify_anchor() {
    local file_path="$1"
    local anchor="$2"
    
    if [[ -z "$anchor" ]]; then
        return 0  # No anchor to verify
    fi
    
    # Check if anchor exists in file (simplified check)
    if grep -q "^#*.*${anchor}" "$file_path" 2>/dev/null; then
        return 0
    else
        return 1
    fi
}

# Main verification process
echo "Scanning markdown files..."
echo ""

find "$PROJECT_ROOT" -name "*.md" -type f | while IFS= read -r file; do
    # Skip certain directories
    if [[ "$file" == *"/node_modules/"* ]] || [[ "$file" == *"/.git/"* ]]; then
        continue
    fi
    
    relative_file="${file#$PROJECT_ROOT/}"
    
    # Extract all links from file
    while IFS= read -r link_line; do
        if [[ -z "$link_line" ]]; then
            continue
        fi
        
        # Extract link text and path
        if [[ "$link_line" =~ \[([^\]]+)\]\(([^)]+)\) ]]; then
            link_text="${BASH_REMATCH[1]}"
            link_path="${BASH_REMATCH[2]}"
            
            TOTAL_LINKS=$((TOTAL_LINKS + 1))
            
            # Skip external links
            if [[ "$link_path" == http://* ]] || [[ "$link_path" == https://* ]] || [[ "$link_path" == mailto:* ]]; then
                VALID_LINKS=$((VALID_LINKS + 1))
                continue
            fi
            
            # Split path and anchor
            if [[ "$link_path" == *"#"* ]]; then
                file_part="${link_path%%#*}"
                anchor_part="${link_path#*#}"
            else
                file_part="$link_path"
                anchor_part=""
            fi
            
            # Verify file
            if verify_file_link "$file_part" "$file"; then
                # Get full file path
                source_dir="$(dirname "$file")"
                if [[ "$file_part" == /* ]]; then
                    full_file_path="${PROJECT_ROOT}${file_part}"
                elif [[ "$file_part" == ../* ]]; then
                    full_file_path="$(cd "$source_dir" && cd "$(dirname "$file_part")" && pwd)/$(basename "$file_part")"
                else
                    full_file_path="${source_dir}/${file_part}"
                fi
                
                # Verify anchor if present
                if [[ -n "$anchor_part" ]]; then
                    if verify_anchor "$full_file_path" "$anchor_part"; then
                        VALID_LINKS=$((VALID_LINKS + 1))
                    else
                        INVALID_ANCHORS+=("$relative_file -> $link_path (anchor: $anchor_part)")
                        echo -e "${YELLOW}WARNING:${NC} Invalid anchor in $relative_file: $link_path"
                    fi
                else
                    VALID_LINKS=$((VALID_LINKS + 1))
                fi
            else
                BROKEN_LINKS+=("$relative_file -> $link_path")
                MISSING_FILES+=("$link_path")
                echo -e "${RED}ERROR:${NC} Broken link in $relative_file: $link_path"
            fi
        fi
    done < <(extract_links "$file")
done

# Generate report
echo ""
echo "=========================================="
echo "Verification Summary"
echo "=========================================="
echo ""
echo "Total Links Found: $TOTAL_LINKS"
echo "Valid Links: $VALID_LINKS"
echo "Broken Links: ${#BROKEN_LINKS[@]}"
echo "Invalid Anchors: ${#INVALID_ANCHORS[@]}"
echo ""

# Create report file
cat > "$REPORT_FILE" << EOF
# CROSS-REFERENCE VERIFICATION REPORT
## Automated Link Verification Results

**Generated:** $(date -u +"%Y-%m-%d %H:%M:%S UTC")
**Project Root:** $PROJECT_ROOT

---

## SUMMARY

- **Total Links Scanned:** $TOTAL_LINKS
- **Valid Links:** $VALID_LINKS
- **Broken Links:** ${#BROKEN_LINKS[@]}
- **Invalid Anchors:** ${#INVALID_ANCHORS[@]}
- **Success Rate:** $(awk "BEGIN {printf \"%.2f\", ($VALID_LINKS/$TOTAL_LINKS)*100}")%

---

## BROKEN LINKS

EOF

if [[ ${#BROKEN_LINKS[@]} -eq 0 ]]; then
    echo "✅ No broken links found!" >> "$REPORT_FILE"
else
    for link in "${BROKEN_LINKS[@]}"; do
        echo "- $link" >> "$REPORT_FILE"
    done
fi

cat >> "$REPORT_FILE" << EOF

---

## INVALID ANCHORS

EOF

if [[ ${#INVALID_ANCHORS[@]} -eq 0 ]]; then
    echo "✅ No invalid anchors found!" >> "$REPORT_FILE"
else
    for anchor in "${INVALID_ANCHORS[@]}"; do
        echo "- $anchor" >> "$REPORT_FILE"
    done
fi

cat >> "$REPORT_FILE" << EOF

---

## RECOMMENDATIONS

1. Fix all broken links identified above
2. Verify and correct invalid anchors
3. Update cross-references in affected documents
4. Re-run verification after fixes

---

**END OF VERIFICATION REPORT**
EOF

echo "Report generated: $REPORT_FILE"
echo ""
echo -e "${GREEN}Verification complete!${NC}"