repotoire 0.8.2

//! Express Security Detector
//!
//! Graph-enhanced detection of Express.js security issues.
//! Uses graph to:
//! - Check middleware chain coverage
//! - Identify routes without authentication
//! - Trace error handling coverage

use crate::detectors::base::{Detector, DetectorConfig};
use crate::models::{deterministic_finding_id, Finding, Severity};
use anyhow::Result;
use regex::Regex;
use std::path::PathBuf;
use std::sync::LazyLock;
use tracing::info;

static EXPRESS_APP: LazyLock<Regex> = LazyLock::new(|| {
    Regex::new(r#"express\(\)|require\(["']express["']\)|from ['"]express['"']"#)
        .expect("valid regex")
});
static ROUTE_HANDLER: LazyLock<Regex> = LazyLock::new(|| {
    Regex::new(r"\.(get|post|put|delete|patch|all|use)\s*\(").expect("valid regex")
});

/// Security features to check
struct SecurityFeatures {
    has_helmet: bool,
    has_cors: bool,
    has_rate_limit: bool,
    has_body_parser_limit: bool,
    #[allow(dead_code)] // Tracked for security audit completeness
    has_hpp: bool,
    has_csrf: bool,
    #[allow(dead_code)] // Tracked for security audit completeness
    has_compression: bool,
    route_count: usize,
    auth_middleware_count: usize,
}

impl SecurityFeatures {
    fn from_content(content: &str) -> Self {
        let lower = content.to_lowercase();
        Self {
            has_helmet: content.contains("helmet"),
            has_cors: content.contains("cors(") || content.contains("cors."),
            has_rate_limit: lower.contains("ratelimit")
                || lower.contains("rate-limit")
                || lower.contains("express-rate"),
            has_body_parser_limit: content.contains("limit:")
                || content.contains("bodyParser") && content.contains("limit"),
            has_hpp: content.contains("hpp"),
            has_csrf: lower.contains("csrf") || lower.contains("csurf"),
            has_compression: content.contains("compression"),
            route_count: ROUTE_HANDLER.find_iter(content).count(),
            auth_middleware_count: Self::count_auth_middleware(content),
        }
    }

    fn count_auth_middleware(content: &str) -> usize {
        let auth_patterns = [
            "passport.",
            "jwt.",
            "jsonwebtoken",
            "express-jwt",
            "isAuthenticated",
            "requireAuth",
            "authenticate",
            "authorize",
            "checkAuth",
            "verifyToken",
        ];
        auth_patterns
            .iter()
            .filter(|p| content.contains(*p))
            .count()
    }

    fn security_score(&self) -> f64 {
        let mut score = 0.0;
        let mut max_score = 0.0;

        // Helmet - critical
        max_score += 25.0;
        if self.has_helmet {
            score += 25.0;
        }

        // Rate limiting - critical for production
        max_score += 20.0;
        if self.has_rate_limit {
            score += 20.0;
        }

        // Body parser limits
        max_score += 15.0;
        if self.has_body_parser_limit {
            score += 15.0;
        }

        // CORS
        max_score += 10.0;
        if self.has_cors {
            score += 10.0;
        }

        // CSRF for non-API apps
        max_score += 10.0;
        if self.has_csrf {
            score += 10.0;
        }

        // Auth middleware
        max_score += 20.0;
        if self.auth_middleware_count > 0 {
            score += 20.0;
        }

        (score / max_score) * 100.0
    }
}

pub struct ExpressSecurityDetector {
    #[allow(dead_code)] // Part of detector pattern, used for file scanning
    repository_path: PathBuf,
    max_findings: usize,
}

impl ExpressSecurityDetector {
    crate::detectors::detector_new!(50);
}

impl Detector for ExpressSecurityDetector {
    fn name(&self) -> &'static str {
        "express-security"
    }
    fn description(&self) -> &'static str {
        "Detects Express.js security issues"
    }

    fn bypass_postprocessor(&self) -> bool {
        true
    }

    fn file_extensions(&self) -> &'static [&'static str] {
        &["js", "ts"]
    }

    fn content_requirements(&self) -> crate::detectors::detector_context::ContentFlags {
        crate::detectors::detector_context::ContentFlags::HAS_EXPRESS
    }

    fn detect(
        &self,
        ctx: &crate::detectors::analysis_context::AnalysisContext,
    ) -> Result<Vec<Finding>> {
        let files = &ctx.as_file_provider();
        // Codebase-level pre-filter: skip if no file uses Express
        let has_express = files
            .files_with_extensions(&["js", "ts"])
            .iter()
            .any(|p| files.content(p).is_some_and(|c| c.contains("express")));
        if !has_express {
            return Ok(vec![]);
        }

        let mut findings = vec![];

        for path in files.files_with_extensions(&["js", "ts", "mjs"]) {
            if findings.len() >= self.max_findings {
                break;
            }

            let path_str = path.to_string_lossy().to_string();

            // Skip test files
            if crate::detectors::base::is_test_path(&path_str) {
                continue;
            }

            if let Some(content) = files.content(path) {
                // Check if this is an Express app
                if !EXPRESS_APP.is_match(&content) {
                    continue;
                }

                let features = SecurityFeatures::from_content(&content);
                let security_score = features.security_score();

                // Build app-level notes
                let mut app_notes = Vec::new();
                app_notes.push(format!("📊 Security Score: {:.0}%", security_score));
                app_notes.push(format!("🛣️ Routes: {}", features.route_count));

                let mut missing = Vec::new();
                if !features.has_helmet {
                    missing.push("helmet");
                }
                if !features.has_rate_limit {
                    missing.push("rate-limit");
                }
                if !features.has_body_parser_limit {
                    missing.push("body-parser-limit");
                }
                if features.auth_middleware_count == 0 {
                    missing.push("auth-middleware");
                }

                if !missing.is_empty() {
                    app_notes.push(format!("❌ Missing: {}", missing.join(", ")));
                }

                let context_notes = format!("\n\n**App Analysis:**\n{}", app_notes.join("\n"));

                // Helmet finding
                if !features.has_helmet {
                    let severity = if features.route_count > 5 {
                        Severity::High // Bigger app = more important
                    } else {
                        Severity::Medium
                    };

                    findings.push(Finding {
                        id: String::new(),
                        detector: "ExpressSecurityDetector".to_string(),
                        severity,
                        title: "Express app missing helmet".to_string(),
                        description: format!(
                            "Helmet sets important security headers to protect against common attacks.{}",
                            context_notes
                        ),
                        affected_files: vec![path.to_path_buf()],
                        line_start: Some(1),
                        line_end: Some(1),
                        suggested_fix: Some(
                            "Install and use helmet:\n\
                             ```bash\n\
                             npm install helmet\n\
                             ```\n\
                             ```javascript\n\
                             const helmet = require('helmet');\n\
                             app.use(helmet());\n\
                             \n\
                             // Or with custom config:\n\
                             app.use(helmet({\n\
                               contentSecurityPolicy: {\n\
                                 directives: {\n\
                                   defaultSrc: [\"'self'\"],\n\
                                   scriptSrc: [\"'self'\", \"trusted-cdn.com\"],\n\
                                 },\n\
                               },\n\
                             }));\n\
                             ```".to_string()
                        ),
                        estimated_effort: Some("10 minutes".to_string()),
                        category: Some("security".to_string()),
                        cwe_id: Some("CWE-693".to_string()),
                        why_it_matters: Some(
                            "Without helmet, your app is missing:\n\
                             • X-Content-Type-Options (prevents MIME sniffing)\n\
                             • X-Frame-Options (prevents clickjacking)\n\
                             • X-XSS-Protection (legacy XSS filter)\n\
                             • Strict-Transport-Security (enforces HTTPS)\n\
                             • Content-Security-Policy (prevents XSS)".to_string()
                        ),
                        ..Default::default()
                    });
                }

                // Rate limiting finding
                if !features.has_rate_limit {
                    let severity = if features.route_count > 5 {
                        Severity::Medium
                    } else {
                        Severity::Low
                    };

                    findings.push(Finding {
                        id: String::new(),
                        detector: "ExpressSecurityDetector".to_string(),
                        severity,
                        title: "Express app missing rate limiting".to_string(),
                        description: format!(
                            "Rate limiting prevents brute force attacks and DoS.{}",
                            context_notes
                        ),
                        affected_files: vec![path.to_path_buf()],
                        line_start: Some(1),
                        line_end: Some(1),
                        suggested_fix: Some(
                            "Install and use express-rate-limit:\n\
                             ```bash\n\
                             npm install express-rate-limit\n\
                             ```\n\
                             ```javascript\n\
                             const rateLimit = require('express-rate-limit');\n\
                             \n\
                             const limiter = rateLimit({\n\
                               windowMs: 15 * 60 * 1000, // 15 minutes\n\
                               max: 100, // limit each IP to 100 requests per windowMs\n\
                               message: 'Too many requests, please try again later.',\n\
                             });\n\
                             \n\
                             app.use(limiter);\n\
                             \n\
                             // Stricter limits for auth endpoints\n\
                             const authLimiter = rateLimit({\n\
                               windowMs: 15 * 60 * 1000,\n\
                               max: 5,\n\
                             });\n\
                             app.use('/api/auth', authLimiter);\n\
                             ```"
                            .to_string(),
                        ),
                        estimated_effort: Some("15 minutes".to_string()),
                        category: Some("security".to_string()),
                        cwe_id: Some("CWE-770".to_string()),
                        why_it_matters: Some(
                            "Without rate limiting, attackers can:\n\
                             • Brute force passwords\n\
                             • Scrape data at scale\n\
                             • DoS your API\n\
                             • Abuse expensive endpoints"
                                .to_string(),
                        ),
                        ..Default::default()
                    });
                }

                // Body parser limit finding
                if !features.has_body_parser_limit {
                    findings.push(Finding {
                        id: String::new(),
                        detector: "ExpressSecurityDetector".to_string(),
                        severity: Severity::Low,
                        title: "No body size limit configured".to_string(),
                        description: "Large request bodies can be used for DoS attacks."
                            .to_string(),
                        affected_files: vec![path.to_path_buf()],
                        line_start: Some(1),
                        line_end: Some(1),
                        suggested_fix: Some(
                            "Set body size limits:\n\
                             ```javascript\n\
                             app.use(express.json({ limit: '10kb' }));\n\
                             app.use(express.urlencoded({ limit: '10kb', extended: true }));\n\
                             ```"
                            .to_string(),
                        ),
                        estimated_effort: Some("5 minutes".to_string()),
                        category: Some("security".to_string()),
                        cwe_id: Some("CWE-400".to_string()),
                        why_it_matters: Some(
                            "Large payloads can exhaust server memory.".to_string(),
                        ),
                        ..Default::default()
                    });
                }

                // Check for error handling
                let has_error_handler = content.contains("err, req, res, next")
                    || content.contains("error, req, res, next")
                    || content.contains("err: Error");

                if !has_error_handler && features.route_count > 3 {
                    findings.push(Finding {
                        id: String::new(),
                        detector: "ExpressSecurityDetector".to_string(),
                        severity: Severity::Medium,
                        title: "No global error handler".to_string(),
                        description: format!(
                            "Express apps should have a global error handler to prevent stack traces from leaking.{}",
                            context_notes
                        ),
                        affected_files: vec![path.to_path_buf()],
                        line_start: Some(1),
                        line_end: Some(1),
                        suggested_fix: Some(
                            "Add a global error handler:\n\
                             ```javascript\n\
                             // Error handler must be the LAST middleware\n\
                             app.use((err, req, res, next) => {\n\
                               console.error(err.stack);\n\
                               res.status(500).json({\n\
                                 error: process.env.NODE_ENV === 'production' \n\
                                   ? 'Internal server error' \n\
                                   : err.message\n\
                               });\n\
                             });\n\
                             ```".to_string()
                        ),
                        estimated_effort: Some("10 minutes".to_string()),
                        category: Some("security".to_string()),
                        cwe_id: Some("CWE-209".to_string()),
                        why_it_matters: Some("Unhandled errors leak stack traces and internal details.".to_string()),
                        ..Default::default()
                    });
                }

                // Check for auth on routes
                if features.auth_middleware_count == 0 && features.route_count > 5 {
                    findings.push(Finding {
                        id: String::new(),
                        detector: "ExpressSecurityDetector".to_string(),
                        severity: Severity::Medium,
                        title: "No authentication middleware detected".to_string(),
                        description: format!(
                            "This Express app has {} routes but no apparent authentication.{}",
                            features.route_count, context_notes
                        ),
                        affected_files: vec![path.to_path_buf()],
                        line_start: Some(1),
                        line_end: Some(1),
                        suggested_fix: Some(
                            "Consider adding authentication:\n\
                             ```javascript\n\
                             // Using Passport.js\n\
                             const passport = require('passport');\n\
                             app.use(passport.initialize());\n\
                             app.use('/api/protected', passport.authenticate('jwt'));\n\
                             \n\
                             // Or custom middleware\n\
                             const requireAuth = (req, res, next) => {\n\
                               if (!req.user) return res.status(401).json({ error: 'Unauthorized' });\n\
                               next();\n\
                             };\n\
                             ```".to_string()
                        ),
                        estimated_effort: Some("1-2 hours".to_string()),
                        category: Some("security".to_string()),
                        cwe_id: Some("CWE-306".to_string()),
                        why_it_matters: Some("APIs without authentication are open to abuse.".to_string()),
                        ..Default::default()
                    });
                }
            }
        }

        info!(
            "ExpressSecurityDetector found {} findings (graph-aware)",
            findings.len()
        );
        Ok(findings)
    }
}

impl crate::detectors::RegisteredDetector for ExpressSecurityDetector {
    fn create(init: &crate::detectors::DetectorInit) -> std::sync::Arc<dyn Detector> {
        std::sync::Arc::new(Self::new(init.repo_path))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::graph::builder::GraphBuilder;

    #[test]
    fn test_detects_missing_helmet() {
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![
            ("app.js", "const express = require('express');\nconst app = express();\n\napp.get('/api/users', (req, res) => {\n  res.json({ users: [] });\n});\n\napp.post('/api/users', (req, res) => {\n  res.json({ created: true });\n});\n\napp.listen(3000);\n"),
        ]);
        let findings = detector.detect(&ctx).expect("detection should succeed");

        assert!(!findings.is_empty(), "Should detect security issues");
        assert!(
            findings.iter().any(|f| f.title.contains("helmet")),
            "Should detect missing helmet. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_secure_express_fewer_findings() {
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![
            ("server.js", "const express = require('express');\nconst helmet = require('helmet');\nconst cors = require('cors');\nconst rateLimit = require('express-rate-limit');\n\nconst app = express();\napp.use(helmet());\napp.use(cors());\napp.use(rateLimit({ windowMs: 15 * 60 * 1000, max: 100 }));\napp.use(express.json({ limit: '10kb' }));\n\napp.get('/api/data', (req, res) => {\n  res.json({ ok: true });\n});\n\napp.listen(3000);\n"),
        ]);
        let findings = detector.detect(&ctx).expect("detection should succeed");

        // Should NOT flag helmet, cors, rate-limit, or body-parser-limit
        assert!(
            !findings.iter().any(|f| f.title.contains("helmet")),
            "Should not flag helmet when present"
        );
        assert!(
            !findings.iter().any(|f| f.title.contains("rate limiting")),
            "Should not flag rate limiting when present"
        );
        assert!(
            !findings.iter().any(|f| f.title.contains("body size limit")),
            "Should not flag body size limit when present"
        );
    }

    #[test]
    fn test_non_express_file_no_findings() {
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![
            ("utils.js", "function add(a, b) {\n  return a + b;\n}\n\nfunction multiply(a, b) {\n  return a * b;\n}\n\nmodule.exports = { add, multiply };\n"),
        ]);
        let findings = detector.detect(&ctx).expect("detection should succeed");

        assert!(
            findings.is_empty(),
            "Non-Express file should produce no findings, got: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_express_app_without_helmet_or_rate_limit() {
        // An Express app with many routes but no helmet or rate limiting
        // should produce findings for both.
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![(
            "server.js",
            "const express = require('express');\nconst app = express();\n\napp.get('/api/users', (req, res) => res.json([]));\napp.post('/api/users', (req, res) => res.json({}));\napp.get('/api/posts', (req, res) => res.json([]));\napp.put('/api/posts/:id', (req, res) => res.json({}));\napp.delete('/api/posts/:id', (req, res) => res.json({}));\napp.get('/api/comments', (req, res) => res.json([]));\n\napp.listen(3000);\n",
        )]);
        let findings = detector.detect(&ctx).expect("detection should succeed");
        assert!(
            findings.iter().any(|f| f.title.contains("helmet")),
            "Should flag missing helmet. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
        assert!(
            findings.iter().any(|f| f.title.contains("rate limiting")),
            "Should flag missing rate limiting for app with >5 routes. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_express_with_helmet_no_helmet_finding() {
        // An Express app with helmet() installed should NOT produce a helmet finding.
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![(
            "app.js",
            "const express = require('express');\nconst helmet = require('helmet');\nconst app = express();\napp.use(helmet());\n\napp.get('/api/data', (req, res) => res.json({ ok: true }));\napp.listen(3000);\n",
        )]);
        let findings = detector.detect(&ctx).expect("detection should succeed");
        assert!(
            !findings.iter().any(|f| f.title.contains("helmet")),
            "Should NOT flag helmet when it is installed. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_express_with_cors_has_cors_detected() {
        // An Express app using cors() should have has_cors = true,
        // so the security score includes CORS points.
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![(
            "app.js",
            "const express = require('express');\nconst cors = require('cors');\nconst app = express();\napp.use(cors({ origin: 'https://example.com' }));\n\napp.get('/api/data', (req, res) => res.json({ ok: true }));\napp.listen(3000);\n",
        )]);
        let findings = detector.detect(&ctx).expect("detection should succeed");
        // CORS is detected, so it shouldn't appear in "missing" list.
        // The detector doesn't produce a specific "CORS" finding — it only tracks
        // CORS presence for the security score. Verify no CORS-related finding exists.
        assert!(
            !findings
                .iter()
                .any(|f| f.title.to_lowercase().contains("cors")),
            "Should not produce a CORS finding when cors middleware is present. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_express_missing_error_handler_with_many_routes() {
        // An Express app with >3 routes and no error handler should be flagged.
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![(
            "app.js",
            "const express = require('express');\nconst app = express();\n\napp.get('/a', (req, res) => res.json({}));\napp.get('/b', (req, res) => res.json({}));\napp.get('/c', (req, res) => res.json({}));\napp.get('/d', (req, res) => res.json({}));\n\napp.listen(3000);\n",
        )]);
        let findings = detector.detect(&ctx).expect("detection should succeed");
        assert!(
            findings.iter().any(|f| f.title.contains("error handler")),
            "Should detect missing global error handler for app with >3 routes. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }

    #[test]
    fn test_express_with_error_handler_no_error_finding() {
        // An Express app with a proper error handler should not produce that finding.
        let store = GraphBuilder::new().freeze();
        let detector = ExpressSecurityDetector::new("/mock/repo");
        let ctx = crate::detectors::analysis_context::AnalysisContext::test_with_mock_files(&store, vec![(
            "app.js",
            "const express = require('express');\nconst app = express();\n\napp.get('/a', (req, res) => res.json({}));\napp.get('/b', (req, res) => res.json({}));\napp.get('/c', (req, res) => res.json({}));\napp.get('/d', (req, res) => res.json({}));\n\napp.use((err, req, res, next) => {\n  console.error(err.stack);\n  res.status(500).json({ error: 'Internal server error' });\n});\n\napp.listen(3000);\n",
        )]);
        let findings = detector.detect(&ctx).expect("detection should succeed");
        assert!(
            !findings.iter().any(|f| f.title.contains("error handler")),
            "Should NOT flag error handler when one is present. Titles: {:?}",
            findings.iter().map(|f| &f.title).collect::<Vec<_>>()
        );
    }
}