use compliance_core::error::CoreError;
use compliance_core::models::dast::{DastEvidence, DastFinding, DastVulnType};
use compliance_core::models::Severity;
use compliance_core::traits::pentest_tool::{PentestTool, PentestToolContext, PentestToolResult};
use serde_json::json;
use tracing::info;

/// Tool that detects console.log and similar debug statements in frontend JavaScript.
pub struct ConsoleLogDetectorTool {
    http: reqwest::Client,
}

/// A detected console statement with its context.
#[derive(Debug)]
struct ConsoleMatch {
    pattern: String,
    file_url: String,
    line_snippet: String,
    line_number: Option<usize>,
}

impl ConsoleLogDetectorTool {
    pub fn new(http: reqwest::Client) -> Self {
        Self { http }
    }

    /// Patterns that indicate debug/logging statements left in production code.
    fn patterns() -> Vec<&'static str> {
        vec![
            "console.log(",
            "console.debug(",
            "console.error(",
            "console.warn(",
            "console.info(",
            "console.trace(",
            "console.dir(",
            "console.table(",
            "debugger;",
            "alert(",
        ]
    }

    /// Extract JavaScript file URLs from an HTML page body.
    fn extract_js_urls(html: &str, base_url: &str) -> Vec<String> {
        let mut urls = Vec::new();
        let base = url::Url::parse(base_url).ok();

        // Simple regex-free extraction of <script src="...">
        let mut search_from = 0;
        while let Some(start) = html[search_from..].find("src=") {
            let abs_start = search_from + start + 4;
            if abs_start >= html.len() {
                break;
            }

            let quote = html.as_bytes().get(abs_start).copied();
            let (_open, close) = match quote {
                Some(b'"') => ('"', '"'),
                Some(b'\'') => ('\'', '\''),
                _ => {
                    search_from = abs_start + 1;
                    continue;
                }
            };

            let val_start = abs_start + 1;
            if let Some(end) = html[val_start..].find(close) {
                let src = &html[val_start..val_start + end];
                if src.ends_with(".js") || src.contains(".js?") || src.contains("/js/") {
                    let full_url = if src.starts_with("http://") || src.starts_with("https://") {
                        src.to_string()
                    } else if src.starts_with("//") {
                        format!("https:{src}")
                    } else if let Some(ref base) = base {
                        base.join(src).map(|u| u.to_string()).unwrap_or_default()
                    } else {
                        format!("{base_url}/{}", src.trim_start_matches('/'))
                    };
                    if !full_url.is_empty() {
                        urls.push(full_url);
                    }
                }
                search_from = val_start + end + 1;
            } else {
                break;
            }
        }

        urls
    }

    /// Search a JS file's contents for console/debug patterns.
    fn scan_js_content(content: &str, file_url: &str) -> Vec<ConsoleMatch> {
        let mut matches = Vec::new();

        for (line_num, line) in content.lines().enumerate() {
            let trimmed = line.trim();
            // Skip comments (basic heuristic)
            if trimmed.starts_with("//") || trimmed.starts_with('*') || trimmed.starts_with("/*") {
                continue;
            }

            for pattern in Self::patterns() {
                if line.contains(pattern) {
                    let snippet = if line.len() > 200 {
                        format!("{}...", &line[..200])
                    } else {
                        line.to_string()
                    };
                    matches.push(ConsoleMatch {
                        pattern: pattern.trim_end_matches('(').to_string(),
                        file_url: file_url.to_string(),
                        line_snippet: snippet.trim().to_string(),
                        line_number: Some(line_num + 1),
                    });
                    break; // One match per line is enough
                }
            }
        }

        matches
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn extract_js_urls_from_html() {
        let html = r#"
            <html>
            <head>
                <script src="/static/app.js"></script>
                <script src="https://cdn.example.com/lib.js"></script>
                <script src='//cdn2.example.com/vendor.js'></script>
            </head>
            </html>
        "#;
        let urls = ConsoleLogDetectorTool::extract_js_urls(html, "https://example.com");
        assert_eq!(urls.len(), 3);
        assert!(urls.contains(&"https://example.com/static/app.js".to_string()));
        assert!(urls.contains(&"https://cdn.example.com/lib.js".to_string()));
        assert!(urls.contains(&"https://cdn2.example.com/vendor.js".to_string()));
    }

    #[test]
    fn extract_js_urls_no_scripts() {
        let html = "<html><body><p>Hello</p></body></html>";
        let urls = ConsoleLogDetectorTool::extract_js_urls(html, "https://example.com");
        assert!(urls.is_empty());
    }

    #[test]
    fn extract_js_urls_filters_non_js() {
        let html = r#"<link src="/style.css"><script src="/app.js"></script>"#;
        let urls = ConsoleLogDetectorTool::extract_js_urls(html, "https://example.com");
        // Only .js files should be extracted
        assert_eq!(urls.len(), 1);
        assert!(urls[0].ends_with("/app.js"));
    }

    #[test]
    fn scan_js_content_finds_console_log() {
        let js = r#"
            function init() {
                console.log("debug info");
                doStuff();
            }
        "#;
        let matches = ConsoleLogDetectorTool::scan_js_content(js, "https://example.com/app.js");
        assert_eq!(matches.len(), 1);
        assert_eq!(matches[0].pattern, "console.log");
        assert_eq!(matches[0].line_number, Some(3));
    }

    #[test]
    fn scan_js_content_finds_multiple_patterns() {
        let js =
            "console.log('a');\nconsole.debug('b');\nconsole.error('c');\ndebugger;\nalert('x');";
        let matches = ConsoleLogDetectorTool::scan_js_content(js, "test.js");
        assert_eq!(matches.len(), 5);
    }

    #[test]
    fn scan_js_content_skips_comments() {
        let js = "// console.log('commented out');\n* console.log('also comment');\n/* console.log('block comment') */";
        let matches = ConsoleLogDetectorTool::scan_js_content(js, "test.js");
        assert!(matches.is_empty());
    }

    #[test]
    fn scan_js_content_one_match_per_line() {
        let js = "console.log('a'); console.debug('b');";
        let matches = ConsoleLogDetectorTool::scan_js_content(js, "test.js");
        // Only one match per line
        assert_eq!(matches.len(), 1);
    }

    #[test]
    fn scan_js_content_empty_input() {
        let matches = ConsoleLogDetectorTool::scan_js_content("", "test.js");
        assert!(matches.is_empty());
    }

    #[test]
    fn patterns_list_is_not_empty() {
        let patterns = ConsoleLogDetectorTool::patterns();
        assert!(patterns.len() >= 8);
        assert!(patterns.contains(&"console.log("));
        assert!(patterns.contains(&"debugger;"));
    }
}

impl PentestTool for ConsoleLogDetectorTool {
    fn name(&self) -> &str {
        "console_log_detector"
    }

    fn description(&self) -> &str {
        "Detects console.log, console.debug, console.error, debugger, and similar debug \
         statements left in production JavaScript. Fetches the HTML page and referenced JS files."
    }

    fn input_schema(&self) -> serde_json::Value {
        json!({
            "type": "object",
            "properties": {
                "url": {
                    "type": "string",
                    "description": "URL of the page to check for console.log leakage"
                },
                "additional_js_urls": {
                    "type": "array",
                    "description": "Optional additional JavaScript file URLs to scan",
                    "items": { "type": "string" }
                }
            },
            "required": ["url"]
        })
    }

    fn execute<'a>(
        &'a self,
        input: serde_json::Value,
        context: &'a PentestToolContext,
    ) -> std::pin::Pin<
        Box<dyn std::future::Future<Output = Result<PentestToolResult, CoreError>> + Send + 'a>,
    > {
        Box::pin(async move {
            let url = input
                .get("url")
                .and_then(|v| v.as_str())
                .ok_or_else(|| CoreError::Dast("Missing required 'url' parameter".to_string()))?;

            let additional_js: Vec<String> = input
                .get("additional_js_urls")
                .and_then(|v| v.as_array())
                .map(|arr| {
                    arr.iter()
                        .filter_map(|v| v.as_str().map(String::from))
                        .collect()
                })
                .unwrap_or_default();

            let target_id = context
                .target
                .id
                .map(|oid| oid.to_hex())
                .unwrap_or_else(|| "unknown".to_string());

            // Fetch the main page
            let response = self
                .http
                .get(url)
                .send()
                .await
                .map_err(|e| CoreError::Dast(format!("Failed to fetch {url}: {e}")))?;

            let html = response.text().await.unwrap_or_default();

            // Scan inline scripts in the HTML
            let mut all_matches = Vec::new();
            let inline_matches = Self::scan_js_content(&html, url);
            all_matches.extend(inline_matches);

            // Extract JS file URLs from the HTML
            let mut js_urls = Self::extract_js_urls(&html, url);
            js_urls.extend(additional_js);
            js_urls.dedup();

            // Fetch and scan each JS file
            for js_url in &js_urls {
                match self.http.get(js_url).send().await {
                    Ok(resp) => {
                        if resp.status().is_success() {
                            let js_content = resp.text().await.unwrap_or_default();
                            // Only scan non-minified-looking files or files where we can still
                            // find patterns (minifiers typically strip console calls, but not always)
                            let file_matches = Self::scan_js_content(&js_content, js_url);
                            all_matches.extend(file_matches);
                        }
                    }
                    Err(_) => continue,
                }
            }

            let mut findings = Vec::new();
            let match_data: Vec<serde_json::Value> = all_matches
                .iter()
                .map(|m| {
                    json!({
                        "pattern": m.pattern,
                        "file": m.file_url,
                        "line": m.line_number,
                        "snippet": m.line_snippet,
                    })
                })
                .collect();

            if !all_matches.is_empty() {
                // Group by file for the finding
                let mut by_file: std::collections::HashMap<&str, Vec<&ConsoleMatch>> =
                    std::collections::HashMap::new();
                for m in &all_matches {
                    by_file.entry(&m.file_url).or_default().push(m);
                }

                for (file_url, matches) in &by_file {
                    let pattern_summary: Vec<String> = matches
                        .iter()
                        .take(5)
                        .map(|m| {
                            format!(
                                "  Line {}: {} - {}",
                                m.line_number.unwrap_or(0),
                                m.pattern,
                                if m.line_snippet.len() > 80 {
                                    format!("{}...", &m.line_snippet[..80])
                                } else {
                                    m.line_snippet.clone()
                                }
                            )
                        })
                        .collect();

                    let evidence = DastEvidence {
                        request_method: "GET".to_string(),
                        request_url: file_url.to_string(),
                        request_headers: None,
                        request_body: None,
                        response_status: 200,
                        response_headers: None,
                        response_snippet: Some(pattern_summary.join("\n")),
                        screenshot_path: None,
                        payload: None,
                        response_time_ms: None,
                    };

                    let total = matches.len();
                    let extra = if total > 5 {
                        format!(" (and {} more)", total - 5)
                    } else {
                        String::new()
                    };

                    let mut finding = DastFinding::new(
                        String::new(),
                        target_id.clone(),
                        DastVulnType::ConsoleLogLeakage,
                        format!("Console/debug statements in {}", file_url),
                        format!(
                            "Found {total} console/debug statements in {file_url}{extra}. \
                         These can leak sensitive information such as API responses, user data, \
                         or internal state to anyone with browser developer tools open."
                        ),
                        Severity::Low,
                        file_url.to_string(),
                        "GET".to_string(),
                    );
                    finding.cwe = Some("CWE-532".to_string());
                    finding.evidence = vec![evidence];
                    finding.remediation = Some(
                        "Remove console.log/debug/error statements from production code. \
                     Use a build step (e.g., babel plugin, terser) to strip console calls \
                     during the production build."
                            .to_string(),
                    );
                    findings.push(finding);
                }
            }

            let total_matches = all_matches.len();
            let count = findings.len();
            info!(
                url,
                js_files = js_urls.len(),
                total_matches,
                "Console log detection complete"
            );

            Ok(PentestToolResult {
                summary: if total_matches > 0 {
                    format!(
                        "Found {total_matches} console/debug statements across {} files.",
                        count
                    )
                } else {
                    format!(
                        "No console/debug statements found in HTML or {} JS files.",
                        js_urls.len()
                    )
                },
                findings,
                data: json!({
                    "total_matches": total_matches,
                    "js_files_scanned": js_urls.len(),
                    "matches": match_data,
                }),
            })
        })
    }
}