from flask import Flask, request, Response
import requests
from flask_cors import CORS

app = Flask(__name__)
# Enable CORS for all routes and all origins
CORS(app, resources={r"/*": {"origins": "*"}}, supports_credentials=True)

ANTHROPIC_API_BASE = "https://api.anthropic.com"


@app.route(
    "/v1/<path:subpath>", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"]
)
def proxy(subpath):
    # For preflight OPTIONS requests, return immediately with appropriate CORS headers
    if request.method == "OPTIONS":
        response = Response()
        response.headers.add("Access-Control-Allow-Origin", "*")
        response.headers.add("Access-Control-Allow-Headers", "*")
        response.headers.add(
            "Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, PATCH, OPTIONS"
        )
        response.headers.add("Access-Control-Allow-Credentials", "true")
        response.headers.add("Access-Control-Max-Age", "3600")
        return response

    # Construct the target URL
    target_url = f"{ANTHROPIC_API_BASE}/v1/{subpath}"

    # Get the request headers
    headers = {
        key: value
        for key, value in request.headers
        if key.lower() not in ("host", "origin", "referer", "accept-encoding")
    }

    # Explicitly set Accept-Encoding to identity to avoid gzip compression
    headers["Accept-Encoding"] = "identity"

    # Convert Authorization: Bearer to x-api-key
    auth_header = headers.get("Authorization")
    if auth_header and auth_header.startswith("Bearer "):
        token = auth_header.replace("Bearer ", "")
        headers["x-api-key"] = token
        # Remove the original Authorization header
        if "Authorization" in headers:
            del headers["Authorization"]

    # Get the request data/params
    data = request.get_data()
    params = request.args

    # Add Anthropic-specific headers
    headers["Anthropic-Version"] = "2023-06-01"

    # Forward the request to Anthropic API
    resp = requests.request(
        method=request.method,
        url=target_url,
        headers=headers,
        data=data,
        params=params,
        stream=True,  # Always use stream=True to handle both streaming and non-streaming responses
    )

    # Create a Flask response object
    def generate():
        for chunk in resp.iter_content(chunk_size=1024):
            yield chunk

    response = Response(
        generate(),
        status=resp.status_code,
        content_type=resp.headers.get("Content-Type"),
    )

    # Copy only required headers from the Anthropic response to our response
    excluded_headers = (
        "transfer-encoding",
        "content-length",
        "connection",
        "content-encoding",
        "vary",
        "accept-ranges",
    )
    for key, value in resp.headers.items():
        if key.lower() not in excluded_headers:
            response.headers[key] = value

    # Add CORS headers to the response
    response.headers.add("Access-Control-Allow-Origin", "*")
    response.headers.add("Access-Control-Allow-Credentials", "true")

    return response


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)