<?php
namespace AskTamMCP\Tools;
defined('ABSPATH') || exit;

/**
 * Skill Tools — read .md skill files from the plugin's skills/ directory.
 *
 * Skills are markdown files that contain design, copywriting, and build instructions
 * for Claude to follow when constructing landing pages, Elementor layouts, etc.
 *
 * Tools:
 *   list_skills      — list all available skills with metadata
 *   get_skill        — read a single skill file by name
 *   get_page_context — read all auto-load skills in one call
 *
 * To add a skill: drop a .md file in skills/ with YAML front matter. No code changes needed.
 */
class SkillTools {

    private static string $skills_dir = '';

    private static function dir(): string {
        if (!self::$skills_dir) {
            self::$skills_dir = plugin_dir_path(dirname(__DIR__)) . 'skills/';
        }
        return self::$skills_dir;
    }

    public static function listSkills(array $args): array {
        $dir   = self::dir();
        $tag   = sanitize_key($args['tag'] ?? '');
        $files = glob($dir . '*.md') ?: [];

        $skills = [];
        foreach ($files as $filepath) {
            $meta = self::parseFrontMatter($filepath);
            if (!$meta) continue;
            if ($tag) {
                $tags = $meta['tags'] ?? [];
                if (!in_array($tag, (array)$tags)) continue;
            }
            $skills[] = [
                'name'        => $meta['name']        ?? basename($filepath, '.md'),
                'description' => $meta['description'] ?? '',
                'version'     => $meta['version']     ?? '1.0.0',
                'auto_load'   => (bool)($meta['auto-load'] ?? false),
                'tags'        => (array)($meta['tags']     ?? []),
                'filename'    => basename($filepath),
            ];
        }
        usort($skills, fn($a, $b) => $b['auto_load'] <=> $a['auto_load']);

        return [
            'total'      => count($skills),
            'skills'     => $skills,
            'skills_dir' => str_replace(ABSPATH, '/', $dir),
            'usage'      => 'Call get_skill(name) to read any skill. Call get_page_context() to load all auto-load skills at once before building a landing page.',
        ];
    }

    public static function getSkill(array $args): array {
        $name = sanitize_file_name($args['name'] ?? '');
        if (empty($name)) throw new \RuntimeException('name is required.');
        $name     = preg_replace('/\.md$/i', '', $name);
        $filepath = self::dir() . $name . '.md';

        $real = realpath($filepath);
        $dir  = realpath(self::dir());
        if (!$real || !str_starts_with($real, $dir)) {
            throw new \RuntimeException("Skill '{$name}' not found.");
        }

        $raw  = file_get_contents($real);
        $meta = self::parseFrontMatterFromContent($raw);
        $body = self::stripFrontMatter($raw);

        return [
            'name'        => $meta['name']        ?? $name,
            'description' => $meta['description'] ?? '',
            'version'     => $meta['version']     ?? '1.0.0',
            'auto_load'   => (bool)($meta['auto-load'] ?? false),
            'tags'        => (array)($meta['tags']     ?? []),
            'content'     => $body,
            'char_count'  => strlen($body),
        ];
    }

    public static function getPageContext(array $args): array {
        $dir   = self::dir();
        $files = glob($dir . '*.md') ?: [];
        $loaded  = [];
        $skipped = [];

        foreach ($files as $filepath) {
            $raw  = file_get_contents($filepath);
            $meta = self::parseFrontMatterFromContent($raw);
            if (!(bool)($meta['auto-load'] ?? false)) {
                $skipped[] = $meta['name'] ?? basename($filepath, '.md');
                continue;
            }
            $loaded[] = ['name' => $meta['name'] ?? basename($filepath, '.md'), 'content' => self::stripFrontMatter($raw)];
        }

        $combined = '';
        foreach ($loaded as $skill) {
            $combined .= "\n\n" . str_repeat('=', 60) . "\n";
            $combined .= "SKILL: {$skill['name']}\n";
            $combined .= str_repeat('=', 60) . "\n\n";
            $combined .= $skill['content'];
        }

        return [
            'loaded_skills'  => array_column($loaded, 'name'),
            'skipped_skills' => $skipped,
            'total_loaded'   => count($loaded),
            'context'        => trim($combined),
            'char_count'     => strlen($combined),
            'usage_note'     => 'This context contains your landing page build instructions. Follow them for every page you build. For motion/CSS patterns call get_skill("motion-and-css") separately.',
        ];
    }

    private static function parseFrontMatter(string $filepath): ?array {
        $content = file_get_contents($filepath);
        if (!$content) return null;
        return self::parseFrontMatterFromContent($content);
    }

    private static function parseFrontMatterFromContent(string $content): array {
        if (!preg_match('/^---\s*\n(.*?)\n---/s', $content, $m)) return [];
        $meta  = [];
        $lines = explode("\n", trim($m[1]));
        foreach ($lines as $line) {
            if (!preg_match('/^([a-zA-Z0-9_\-]+)\s*:\s*(.*)$/', $line, $lm)) continue;
            $key = trim($lm[1]);
            $val = trim($lm[2]);
            $val = preg_replace('/^["\'](.*)["\']$/', '$1', $val);
            if (strtolower($val) === 'true')       $val = true;
            elseif (strtolower($val) === 'false')  $val = false;
            elseif (is_numeric($val) && !str_starts_with($val, '0') && !str_contains($val, '.')) $val = (int)$val;
            if (is_string($val) && str_starts_with($val, '[') && str_ends_with($val, ']')) {
                $val = array_map(fn($v) => trim(trim($v), '"\''), explode(',', substr($val, 1, -1)));
            }
            $meta[$key] = $val;
        }
        return $meta;
    }

    private static function stripFrontMatter(string $content): string {
        return trim(preg_replace('/^---\s*\n.*?\n---\s*\n/s', '', $content));
    }
}