#!/usr/bin/env bash
# Validates code fence syntax in markdown files for MkDocs/GitHub Pages compatibility.
# MkDocs does not support comma-separated attributes in code fences (e.g., ```csharp,ignore).
#
# Exit codes: 0 = success, 1 = validation errors found
#
# Usage: ./scripts/check-code-fence-syntax.sh [DOCS_DIR]
# Default docs directory: docs/

set -euo pipefail

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

# Script location and default docs directory
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
DOCS_DIR="${1:-$REPO_ROOT/docs}"

# Counter for issues
ISSUES=0

echo "========================================"
echo "Code Fence Syntax Validator"
echo "========================================"
echo ""
printf "Docs Directory: ${BLUE}%s${NC}\n" "$DOCS_DIR"
echo ""

# Check if docs directory exists
if [ ! -d "$DOCS_DIR" ]; then
    printf "${RED}ERROR: Docs directory not found: %s${NC}\n" "$DOCS_DIR"
    exit 1
fi

echo "----------------------------------------"
echo "Checking for invalid code fence syntax"
echo "----------------------------------------"
echo ""
echo "Pattern: code fences with comma-separated attributes"
echo "  Invalid: \`\`\`csharp,ignore or \`\`\`rust,no_run"
echo "  Valid:   \`\`\`csharp or \`\`\`rust"
echo ""

# Array to store issues for summary
declare -a ISSUE_LIST

# Find all markdown files and check for invalid code fence syntax
# Pattern matches code fences with language followed by comma and attributes
# Examples of invalid patterns:
#   ```csharp,ignore
#   ```rust,no_run
#   ```python,something
while IFS= read -r -d '' mdfile; do
    line_num=0

    while IFS= read -r line || [[ -n "$line" ]]; do
        line_num=$((line_num + 1))

        # Check for code fence with comma-separated attributes
        # Pattern: ``` followed by word characters (language), then comma, then more characters
        # This matches the opening of a code fence only
        if [[ "$line" =~ ^[[:space:]]*([\`]{3,}|\~{3,})([a-zA-Z][a-zA-Z0-9_+-]*),([a-zA-Z0-9_,+-]+) ]]; then
            language="${BASH_REMATCH[2]}"
            attributes="${BASH_REMATCH[3]}"

            # Get relative path for cleaner output
            rel_path="${mdfile#"$REPO_ROOT"/}"

            printf "${RED}ISSUE${NC} %s:%d\n" "$rel_path" "$line_num"
            printf "  Found: \`\`\`%s,%s\n" "$language" "$attributes"
            printf "  Fix:   \`\`\`%s  ${YELLOW}(remove ',%s')${NC}\n" "$language" "$attributes"
            echo ""

            ISSUE_LIST+=("$rel_path:$line_num: \`\`\`$language,$attributes -> \`\`\`$language")
            ISSUES=$((ISSUES + 1))
        fi
    done < "$mdfile"
done < <(find "$DOCS_DIR" -name "*.md" -type f -print0 2>/dev/null)

echo "----------------------------------------"
echo "Summary"
echo "----------------------------------------"

if [ "$ISSUES" -eq 0 ]; then
    printf "${GREEN}No code fence syntax issues found.${NC}\n"
    echo ""
    printf "${GREEN}VALIDATION PASSED${NC}\n"
    exit 0
else
    printf "${RED}Found %d code fence syntax issue(s)${NC}\n" "$ISSUES"
    echo ""
    echo "MkDocs and GitHub Pages do not support comma-separated"
    echo "attributes in code fences. Remove the comma and everything"
    echo "after it from the language identifier."
    echo ""
    printf "${RED}VALIDATION FAILED${NC}\n"
    exit 1
fi