from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from fastapi.responses import FileResponse
from pydantic import BaseModel
import re, os, requests, base64
from groq import Groq

app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

# ── helpers ──────────────────────────────────────────────────────────────────

def parse_github_url(url):
    url = url.strip().rstrip('/')
    m = re.match(r"https://github\.com/([^/]+)/([^/]+)/blob/[^/]+/(.+)", url)
    if m:
        return m.group(1), m.group(2), m.group(3)
    return None, None, None

def get_file_content(owner, repo, path):
    token = os.getenv("GITHUB_TOKEN", "")
    headers = {"Authorization": f"token {token}"} if token else {}
    r = requests.get(f"https://api.github.com/repos/{owner}/{repo}/contents/{path}", headers=headers, timeout=15)
    if r.status_code != 200:
        return None, f"GitHub API error: {r.status_code}"
    return base64.b64decode(r.json()["content"]).decode("utf-8", errors="replace"), None


def scan_file(owner, repo, file_path):
    code, err = get_file_content(owner, repo, file_path)
    if err:
        return {"error": err}
    if len(code) > 6000:
        code = code[:6000] + "\n... [truncated]"
    groq_key = os.getenv("GROQ_API_KEY", "")
    if not groq_key:
        return {"error": "GROQ_API_KEY not configured"}
    client = Groq(api_key=groq_key)
    prompt = f"""You are a cybersecurity expert. Analyze this code for security vulnerabilities.

File: {file_path}
Repository: {owner}/{repo}

```
{code}
```

Provide a detailed security analysis in this exact markdown format:

# Security Analysis Report

## File Overview
- Repository: {owner}/{repo}
- File: {file_path}
- Language: [detected language]
- Lines analyzed: [count]

## Vulnerabilities Found

### [Vulnerability Name] — [CRITICAL/HIGH/MEDIUM/LOW]
- **Line**: [line number]
- **Code**: `[snippet]`
- **Issue**: [explanation]
- **CVE Reference**: [CVE ID if applicable]

## Remediation
[Specific fixes with corrected code]

## Risk Summary
- Critical: [n] | High: [n] | Medium: [n] | Low: [n]
- **Overall Risk**: [CRITICAL/HIGH/MEDIUM/LOW]
"""
    try:
        response = client.chat.completions.create(
            model="llama-3.3-70b-versatile",
            messages=[{"role": "user", "content": prompt}],
            temperature=0.1,
            max_tokens=4096,
        )
        return {"result": response.choices[0].message.content}
    except Exception as e:
        return {"error": f"AI analysis failed: {str(e)}"}


# ── API routes ────────────────────────────────────────────────────────────────

class ScanRequest(BaseModel):
    url: str

@app.get("/api/health")
def health():
    return {"status": "ok", "groq_key_set": bool(os.getenv("GROQ_API_KEY"))}

@app.post("/api/scan")
def scan(req: ScanRequest):
    owner, repo, file_path = parse_github_url(req.url)
    if not owner or not repo or not file_path:
        return {"error": "Invalid GitHub file URL. Use format: github.com/owner/repo/blob/branch/file"}
    return scan_file(owner, repo, file_path)

# ── Serve React frontend ──────────────────────────────────────────────────────

if os.path.exists("static"):
    app.mount("/assets", StaticFiles(directory="static/assets"), name="assets")

    @app.get("/")
    def serve_root():
        return FileResponse("static/index.html")

    @app.get("/{full_path:path}")
    def serve_spa(full_path: str):
        return FileResponse("static/index.html")