"""The ONLY module permitted to call ``requests.*``.

Enforced by tests/code_coverage_tests/check_e2e_no_raw_requests.py. Every request
body / query / header / response is a pydantic model; outcomes are a tagged union
(``Result[R]``) so callers ``match`` on them instead of catching exceptions.

Named e2e_http (not http) so it does not shadow the stdlib ``http`` package that
requests itself imports.
"""

from __future__ import annotations

from typing import Generic, Iterator, Literal, NewType, TypeVar, cast

import pytest
import requests
from pydantic import BaseModel, ConfigDict, Field

URL = NewType("URL", str)


class Headers(BaseModel):
    """Base for header models. Subclasses may alias to hyphenated header names
    (e.g. ``x-litellm-api-key``); serialization uses by_alias."""

    model_config = ConfigDict(populate_by_name=True)


class AuthHeaders(Headers):
    # litellm accepts either; set whichever the call needs, leave the other None.
    authorization: str | None = None
    x_litellm_api_key: str | None = Field(default=None, alias="x-litellm-api-key")


class NoBody(BaseModel):
    """Empty body/query for routes that take none."""


class FileUploadForm(BaseModel):
    """Multipart form fields for POST /v1/files. The file bytes are passed
    separately; `model` is not here because the proxy reads it from the query
    (?model=) not the form."""

    purpose: str = "batch"
    target_model_names: str | None = None
    custom_llm_provider: str | None = None


# ---------- Result types ----------

R = TypeVar("R", bound=BaseModel)


class Success(BaseModel, Generic[R]):
    kind: Literal["success"] = "success"
    data: R


class NetworkError(BaseModel):
    kind: Literal["network"] = "network"
    message: str


class UnauthorizedError(BaseModel):
    kind: Literal["unauthorized"] = "unauthorized"


class RateLimitedError(BaseModel):
    kind: Literal["rate_limited"] = "rate_limited"
    retry_after_seconds: int | None = None
    # litellm overloads 429 for budget_exceeded too, so keep the body to tell them apart.
    body: str = ""


class ValidationError(BaseModel):
    kind: Literal["validation"] = "validation"
    message: str


class UnknownApiError(BaseModel):
    kind: Literal["unknown"] = "unknown"
    status_code: int
    body: str


type Result[R: BaseModel] = (
    Success[R]
    | NetworkError
    | UnauthorizedError
    | RateLimitedError
    | ValidationError
    | UnknownApiError
)


class ProbeResult(BaseModel):
    """A route's reachability: status + body, no schema validation. Healthy ==
    route exists (not 404) and the handler did not crash (not 5xx)."""

    status_code: int
    body: str

    @property
    def healthy(self) -> bool:
        return 200 <= self.status_code < 500 and self.status_code != 404


class StreamingResponse(BaseModel):
    """Raw outcome for calls whose body is provider-native or streamed: status, the
    x-litellm-call-id header (== SpendLogs.request_id), the content-type (which
    tells streaming `text/event-stream` from non-streaming `application/json`), and
    the body. Used by passthrough and streaming, where one validated JSON model
    does not fit."""

    status_code: int
    call_id: str | None = None  # x-litellm-call-id header
    content_type: str | None = None
    body: str
    chunks: int = 0  # streamed events (0 for non-streaming)

    @property
    def ok(self) -> bool:
        return 200 <= self.status_code < 300

    @property
    def is_streaming(self) -> bool:
        return "text/event-stream" in (self.content_type or "")


def _hdr(resp: requests.Response, name: str) -> str | None:
    value = resp.headers.get(name)
    return value if isinstance(value, str) else None


def unwrap[R: BaseModel](result: Result[R]) -> R:
    match result:
        case Success(data=data):
            return data
        case _:
            raise AssertionError(result)


def is_ok[R: BaseModel](result: Result[R]) -> bool:
    match result:
        case Success():
            return True
        case _:
            return False


def require_successful_call(result: StreamingResponse) -> None:
    """A call that should have succeeded but didn't is a hard failure, never a skip:
    if the proxy can't make a call it's expected to, the test must fail."""
    if result.ok:
        return
    pytest.fail(
        f"upstream call failed (status {result.status_code}); body={result.body[:300]}"
    )


def _headers(headers: BaseModel) -> dict[str, str]:
    dumped: dict[str, object] = headers.model_dump(by_alias=True, exclude_none=True)
    return {key: str(value) for key, value in dumped.items()}


def _params(params: BaseModel | None) -> dict[str, str]:
    if params is None:
        return {}
    dumped: dict[str, object] = params.model_dump(by_alias=True, exclude_none=True)
    return {key: str(value) for key, value in dumped.items()}


def _classify[R: BaseModel](
    resp: requests.Response, response_type: type[R]
) -> Result[R]:
    if resp.status_code == 401:
        return UnauthorizedError()
    if resp.status_code == 429:
        return RateLimitedError(body=resp.text)
    if not resp.ok:
        return UnknownApiError(status_code=resp.status_code, body=resp.text)
    try:
        return Success(data=response_type.model_validate(resp.json()))
    except Exception as exc:  # noqa: BLE001 - any parse/validation failure is a value
        return ValidationError(message=str(exc))


def post[R: BaseModel](
    url: URL,
    *,
    headers: BaseModel,
    json: BaseModel,
    response_type: type[R],
    timeout: float = 30.0,
) -> Result[R]:
    try:
        resp = requests.post(
            str(url),
            headers=_headers(headers),
            json=json.model_dump(by_alias=True, exclude_none=True),
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return NetworkError(message=str(exc))
    return _classify(resp, response_type)


def get[R: BaseModel](
    url: URL,
    *,
    headers: BaseModel,
    params: BaseModel,
    response_type: type[R],
    timeout: float = 30.0,
) -> Result[R]:
    try:
        resp = requests.get(
            str(url),
            headers=_headers(headers),
            params=params.model_dump(by_alias=True, exclude_none=True),
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return NetworkError(message=str(exc))
    return _classify(resp, response_type)


def delete[R: BaseModel](
    url: URL,
    *,
    headers: BaseModel,
    json: BaseModel,
    response_type: type[R],
    timeout: float = 30.0,
) -> Result[R]:
    try:
        resp = requests.delete(
            str(url),
            headers=_headers(headers),
            json=json.model_dump(by_alias=True, exclude_none=True),
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return NetworkError(message=str(exc))
    return _classify(resp, response_type)


def probe(
    url: URL, *, headers: BaseModel, params: BaseModel, timeout: float = 30.0
) -> ProbeResult:
    try:
        resp = requests.get(
            str(url),
            headers=_headers(headers),
            params=params.model_dump(by_alias=True, exclude_none=True),
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return ProbeResult(status_code=-1, body=str(exc))
    return ProbeResult(status_code=resp.status_code, body=resp.text)


def _streaming_outcome(resp: requests.Response, stream: bool) -> StreamingResponse:
    call_id = _hdr(resp, "x-litellm-call-id")
    content_type = _hdr(resp, "content-type")
    if not stream or not (200 <= resp.status_code < 300):
        return StreamingResponse(
            status_code=resp.status_code,
            call_id=call_id,
            content_type=content_type,
            body=resp.text,
        )
    lines = cast("Iterator[bytes]", resp.iter_lines())
    chunks = sum(1 for line in lines if line)
    return StreamingResponse(
        status_code=resp.status_code,
        call_id=call_id,
        content_type=content_type,
        body="<streamed>",
        chunks=chunks,
    )


def send(
    url: URL,
    *,
    headers: BaseModel,
    json: BaseModel,
    params: BaseModel | None = None,
    stream: bool = False,
    timeout: float = 60.0,
) -> StreamingResponse:
    """Raw POST returning the unparsed HTTP outcome: status, full body, and the
    x-litellm-call-id header. For native/passthrough bodies and for calls judged by
    status rather than a typed JSON model (e.g. a budget block is a non-2xx). With
    ``stream=True`` the SSE body is consumed and its events counted instead."""
    try:
        resp = requests.post(
            str(url),
            headers=_headers(headers),
            params=_params(params),
            json=json.model_dump(by_alias=True, exclude_none=True),
            stream=stream,
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return StreamingResponse(status_code=-1, body=str(exc))
    return _streaming_outcome(resp, stream)


def stream(
    url: URL, *, headers: BaseModel, json: BaseModel, timeout: float = 60.0
) -> StreamingResponse:
    """Streaming (SSE) call: consumes the stream counting events, and captures the
    x-litellm-call-id + content-type headers. Body is elided."""
    return send(url, headers=headers, json=json, stream=True, timeout=timeout)


def upload[R: BaseModel](
    url: URL,
    *,
    headers: BaseModel,
    form: FileUploadForm,
    filename: str,
    content: bytes,
    params: BaseModel | None = None,
    response_type: type[R],
    timeout: float = 60.0,
) -> Result[R]:
    """Multipart POST for file uploads (/v1/files). Form fields come from `form`,
    the file bytes are sent as the `file` part, and `params` carries any query
    routing (e.g. ?model=). requests sets the multipart Content-Type itself."""
    dumped: dict[str, object] = form.model_dump(by_alias=True, exclude_none=True)
    data = {key: str(value) for key, value in dumped.items()}
    try:
        resp = requests.post(
            str(url),
            headers=_headers(headers),
            params=_params(params),
            data=data,
            files={"file": (filename, content, "application/jsonl")},
            timeout=timeout,
        )
    except requests.RequestException as exc:
        return NetworkError(message=str(exc))
    return _classify(resp, response_type)


def download(
    url: URL, *, headers: BaseModel, timeout: float = 60.0
) -> StreamingResponse:
    """Raw GET for file content (/v1/files/{id}/content): provider-native bytes, no
    schema. Returns the decoded body and the x-litellm-call-id header."""
    try:
        resp = requests.get(str(url), headers=_headers(headers), timeout=timeout)
    except requests.RequestException as exc:
        return StreamingResponse(status_code=-1, body=str(exc))
    return StreamingResponse(
        status_code=resp.status_code,
        call_id=_hdr(resp, "x-litellm-call-id"),
        content_type=_hdr(resp, "content-type"),
        body=resp.text,
    )