#!/usr/bin/env python3
"""Local dev proxy: serves www/ statically and proxies /api/* to the Pager."""
import argparse
import http.server
import urllib.request
import urllib.error


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument('--pager-host', default='172.16.52.1')
    ap.add_argument('--pager-port', type=int, default=8080)
    ap.add_argument('--port', type=int, default=8000)
    ap.add_argument('--www', default='payload/user/remote_access/pager-webui/www')
    args = ap.parse_args()
    api_target = 'http://%s:%d' % (args.pager_host, args.pager_port)

    class Proxy(http.server.SimpleHTTPRequestHandler):
        def __init__(self, *a, **kw):
            super().__init__(*a, directory=args.www, **kw)

        def log_message(self, fmt, *a):
            pass

        def _serve_dev_config(self):
            body = ('window.PAGER_CONFIG = { apiBase: "", wsBase: "", '
                    'terminalWs: "ws://%s:1471/api/terminal/openWs", '
                    'pagerScreenWs: "ws://%s:1471/api/pager/display/screen.ws", '
                    'pagerKeysWs: "ws://%s:1471/api/pager/input/keys.ws" };\n'
                    % (args.pager_host, args.pager_host, args.pager_host)).encode()
            self.send_response(200)
            self.send_header('Content-Type', 'text/javascript')
            self.send_header('Content-Length', str(len(body)))
            self.send_header('Cache-Control', 'no-cache')
            self.end_headers()
            self.wfile.write(body)
            return True

        def _proxy(self, method):
            body = None
            if self.headers.get('Content-Length'):
                body = self.rfile.read(int(self.headers['Content-Length']))
            req = urllib.request.Request(api_target + self.path, data=body, method=method)
            if self.headers.get('Cookie'):
                req.add_header('Cookie', self.headers['Cookie'])
            req.add_header('Content-Type', self.headers.get('Content-Type', 'application/json'))
            try:
                with urllib.request.urlopen(req, timeout=25) as r:
                    data = r.read()
                    self.send_response(r.status)
                    self.send_header('Content-Type', r.headers.get('Content-Type', 'application/octet-stream'))
                    self.send_header('Content-Length', str(len(data)))
                    for sc in r.headers.get_all('Set-Cookie', []):
                        self.send_header('Set-Cookie', sc)
                    self.end_headers()
                    self.wfile.write(data)
            except urllib.error.HTTPError as e:
                data = e.read()
                self.send_response(e.code)
                self.send_header('Content-Type', e.headers.get('Content-Type', 'application/json'))
                self.send_header('Content-Length', str(len(data)))
                for sc in e.headers.get_all('Set-Cookie', []):
                    self.send_header('Set-Cookie', sc)
                self.end_headers()
                self.wfile.write(data)

        def do_GET(self):
            if self.path == '/js/config.js':
                return self._serve_dev_config()
            if self.path.startswith('/api/'):
                return self._proxy('GET')
            return super().do_GET()

        def do_POST(self):
            return self._proxy('POST') if self.path.startswith('/api/') else self.send_error(404)

        def do_DELETE(self):
            return self._proxy('DELETE') if self.path.startswith('/api/') else self.send_error(404)

    http.server.ThreadingHTTPServer(('127.0.0.1', args.port), Proxy).serve_forever()


if __name__ == '__main__':
    main()