"""Python 3.10+, standard library only. Read /examples/README.md first."""
import hashlib
import json
import os
from pathlib import Path
import re
import secrets
import sys
import urllib.error
import urllib.parse
import urllib.request

ORIGIN = "https://postedly.com"
PROTOCOL = "2025-06-18"


class NoRedirect(urllib.request.HTTPRedirectHandler):
    def redirect_request(self, req, fp, code, msg, headers, newurl):
        raise RuntimeError("Unexpected redirect; credentials were not forwarded.")


class Postedly:
    def __init__(self, access_token, opener=None):
        if not access_token or re.search(r"\s", access_token):
            raise ValueError("Supply an existing OAuth access token through a secure environment.")
        self.token = access_token
        self.opener = opener or urllib.request.build_opener(NoRedirect())

    def request(self, path, method="GET", payload=None, body=None, content_type=None):
        url = urllib.parse.urljoin(ORIGIN, path)
        if urllib.parse.urlsplit(url)[:2] != ("https", "postedly.com"):
            raise ValueError("Refusing to send credentials to another origin.")
        headers = {"Authorization": f"Bearer {self.token}", "Accept": "application/json", "MCP-Protocol-Version": PROTOCOL}
        if payload is not None:
            body, content_type = json.dumps(payload).encode(), "application/json"
        if content_type:
            headers["Content-Type"] = content_type
        request = urllib.request.Request(url, data=body, headers=headers, method=method)
        try:
            with self.opener.open(request, timeout=30) as response:
                if response.status == 202 and path == "/mcp/send":
                    return None
                return json.load(response)
        except urllib.error.HTTPError as error:
            # Do not print response bodies, credentials, contact details or private URLs.
            raise RuntimeError(f"HTTP {error.code}. No automatic retry; consult /agent-guide.md.") from None
        except (urllib.error.URLError, TimeoutError, OSError, ValueError):
            raise RuntimeError("Request outcome unconfirmed. Do not replay mutations. Read existing orders/status; see the recovery guide.") from None

    def review_link(self, quote_id):
        initialized = self.request("/mcp/send", "POST", {"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {"protocolVersion": PROTOCOL, "capabilities": {}, "clientInfo": {"name": "Postedly Python example", "version": "1.0.0"}}})
        if initialized.get("error") or initialized.get("result", {}).get("protocolVersion") != PROTOCOL:
            raise RuntimeError("MCP initialization failed.")
        self.request("/mcp/send", "POST", {"jsonrpc": "2.0", "method": "notifications/initialized"})
        result = self.request("/mcp/send", "POST", {"jsonrpc": "2.0", "id": 2, "method": "tools/call", "params": {"name": "postedly_checkout", "arguments": {"quoteId": quote_id}}})
        tool_result = result.get("result", {})
        review = tool_result.get("structuredContent", {})
        if result.get("error") or tool_result.get("isError") or review.get("requiresBrowserApproval") is not True:
            raise RuntimeError("Review link unavailable. Keep the existing quote; do not create a replacement order.")
        return review

    def prepare(self, file_bytes, filename, inputs, checkpoint=lambda state: None):
        service = inputs.get("service")
        if service not in ("fax", "letter", "certified", "postcard"):
            raise ValueError("Choose a supported document service.")
        if not 0 < len(file_bytes) <= 10_485_760:
            raise ValueError("File must be 1 byte through 10 MiB.")
        if not filename or len(filename) > 180 or re.search(r'[\r\n\x00/\\"]', filename):
            raise ValueError("Use a filename without paths, quotes or control characters, at most 180 characters.")
        catalog = self.request("/api/catalog")
        if not any(item["id"] == service and item["available"] for item in catalog["services"]):
            raise RuntimeError("This service is not currently available.")
        account = self.request("/api/session")
        if not account.get("verified") or account.get("email", "").lower() != inputs.get("sender", {}).get("email", "").lower():
            raise RuntimeError("Sender email must match the verified OAuth account.")
        expected_hash = hashlib.sha256(file_bytes).hexdigest()
        boundary = "postedly-" + secrets.token_hex(24)
        # Actual bytes, never a filename/URL disguised as a file. Boundary is random.
        parts = []
        for key, value in (("service", service), ("expectedSha256", expected_hash)):
            parts.append(f'--{boundary}\r\nContent-Disposition: form-data; name="{key}"\r\n\r\n{value}\r\n'.encode())
        parts.extend([f'--{boundary}\r\nContent-Disposition: form-data; name="file"; filename="{filename}"\r\nContent-Type: application/octet-stream\r\n\r\n'.encode(), file_bytes, f"\r\n--{boundary}--\r\n".encode()])
        document = self.request("/api/documents", "POST", body=b"".join(parts), content_type=f"multipart/form-data; boundary={boundary}")
        state = {"document": document}
        checkpoint(state)
        if document.get("sha256") != expected_hash or not document.get("id"):
            raise RuntimeError("Stored file checksum or document ID is invalid.")
        state["quote"] = self.request("/api/quotes", "POST", {"service": service, "documentId": document["id"], "recipient": inputs["recipient"], "sender": inputs["sender"], "options": inputs.get("options", {})})
        checkpoint(state)
        # Only a review link: the sender approves and pays in the browser.
        state["review"] = self.review_link(state["quote"]["id"])
        checkpoint(state)
        return state

    def status(self, order_id=None):
        return self.request("/api/orders/" + urllib.parse.quote(order_id, safe="") if order_id else "/api/orders")


def main():
    args = sys.argv[1:]
    if not args or (args[0] == "prepare" and len(args) != 4) or (args[0] == "status" and len(args) not in (2, 3)) or args[0] not in ("prepare", "status"):
        raise ValueError("Usage: python3 postedly.py prepare request.json document.pdf private-result.json | status private-result.json [order-id]")
    client = Postedly(os.environ.get("POSTEDLY_ACCESS_TOKEN"))
    output = args[3] if args[0] == "prepare" else args[1]
    # Never overwrite a previous run. Private links/contact details stay owner-only.
    descriptor = os.open(output, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o600)
    with os.fdopen(descriptor, "w", encoding="utf-8") as file:
        def checkpoint(state):
            file.seek(0)
            json.dump(state, file, indent=2)
            file.truncate()
            file.flush()
            os.fsync(file.fileno())
        if args[0] == "prepare":
            client.prepare(Path(args[2]).read_bytes(), Path(args[2]).name, json.loads(Path(args[1]).read_text()), checkpoint)
        else:
            checkpoint(client.status(args[2] if len(args) == 3 else None))
    print("Private result saved. For prepare, open review.url locally and approve only after checking the proof, recipient, total and terms.")


if __name__ == "__main__":
    try:
        main()
    except Exception as error:
        print(str(error), file=sys.stderr)
        sys.exit(1)