"""OpenAI and OpenRouter calls, stdlib only.

Transcription runs on either provider: OpenRouter mirrors OpenAI's
/audio/transcriptions endpoint field for field, so one multipart request serves
both and only the key, the base URL and the model id change. Cleanup is always
OpenRouter.
"""

import collections
import json
import mimetypes
import os
import secrets
import urllib.error
import urllib.request

from i18n import t

APP_URL = "https://github.com/yusufipk/dikte"
USER_AGENT = f"dikte/1.0 (+{APP_URL})"
OPENAI_URL = "https://api.openai.com/v1"
OPENROUTER_URL = "https://openrouter.ai/api/v1"

# Where a transcription request goes; built by config.Config.transcribe_target().
# `service` is the name the user sees in an error, `provider` the one the code
# branches on.
Target = collections.namedtuple("Target", "provider service api_key base_url model")


def timestamp_model(provider):
    """Only whisper-1 returns segment times, and OpenRouter namespaces the id."""
    return "openai/whisper-1" if provider == "openrouter" else "whisper-1"


class ApiError(Exception):
    def __init__(self, message, status=None):
        super().__init__(message)
        self.status = status


def explain(exc, service):
    """Turn an HTTP status into something the user can act on."""
    if exc.status in (401, 403):
        return ApiError(t("{service} rejected the API key (HTTP {code}). Open "
                          "Settings and check it.", service=service, code=exc.status),
                        exc.status)
    if exc.status == 402:
        return ApiError(t("{service} says the account is out of credit (HTTP 402).",
                          service=service), exc.status)
    if exc.status == 429:
        return ApiError(t("{service} is rate limiting you (HTTP 429). Try again in "
                          "a moment.", service=service), exc.status)
    return ApiError(f"{service}: {exc}", exc.status)


def _request(url, data, headers, timeout=120):
    req = urllib.request.Request(url, data=data, headers=headers, method="POST")
    try:
        with urllib.request.urlopen(req, timeout=timeout) as resp:
            return json.loads(resp.read().decode("utf-8"))
    except urllib.error.HTTPError as exc:
        body = exc.read().decode("utf-8", "replace")
        raise ApiError(f"HTTP {exc.code}: {_extract_error(body)}", exc.code) from exc
    except urllib.error.URLError as exc:
        raise ApiError(t("Could not connect: {reason}", reason=exc.reason)) from exc
    except json.JSONDecodeError as exc:
        raise ApiError(t("Could not parse the response: {error}", error=exc)) from exc


def _extract_error(body):
    try:
        payload = json.loads(body)
    except json.JSONDecodeError:
        return body[:300]
    err = payload.get("error")
    if isinstance(err, dict):
        return err.get("message") or json.dumps(err)[:300]
    if isinstance(err, str):
        return err
    return body[:300]


def _multipart(fields, file_field, file_path):
    """Build a multipart/form-data body; returns (body, content-type)."""
    boundary = "----dikte" + secrets.token_hex(16)
    out = bytearray()
    for name, value in fields:
        if value is None or value == "":
            continue
        out += f"--{boundary}\r\n".encode()
        out += f'Content-Disposition: form-data; name="{name}"\r\n\r\n'.encode()
        out += str(value).encode("utf-8") + b"\r\n"

    filename = os.path.basename(file_path)
    ctype = mimetypes.guess_type(filename)[0] or "application/octet-stream"
    with open(file_path, "rb") as fh:
        payload = fh.read()
    out += f"--{boundary}\r\n".encode()
    out += (
        f'Content-Disposition: form-data; name="{file_field}"; filename="{filename}"\r\n'
        f"Content-Type: {ctype}\r\n\r\n"
    ).encode()
    out += payload + b"\r\n"
    out += f"--{boundary}--\r\n".encode()
    return bytes(out), f"multipart/form-data; boundary={boundary}"


def _headers(provider, api_key, content_type=None):
    headers = {"Authorization": f"Bearer {api_key}", "User-Agent": USER_AGENT}
    if content_type:
        headers["Content-Type"] = content_type
    if provider == "openrouter":
        # What OpenRouter attributes the calls to on its app leaderboard.
        headers["HTTP-Referer"] = APP_URL
        headers["X-Title"] = "Dikte"
    return headers


def _transcribe_request(target, wav_path, language, prompt, response_format,
                        granularity=None, timeout=300):
    if not target.api_key:
        raise ApiError(t("{service} API key is empty. Add it in Settings.",
                         service=target.service))
    fields = [("model", target.model), ("response_format", response_format)]
    if language and language != "auto":
        fields.append(("language", language))
    # OpenRouter takes the hint field and throws it away, so spare it the bytes.
    # The same words still reach the cleanup model as a glossary.
    if prompt and target.provider == "openai":
        fields.append(("prompt", prompt))
    if granularity:
        fields.append(("timestamp_granularities[]", granularity))
    body, ctype = _multipart(fields, "file", wav_path)
    try:
        return _request(
            f"{target.base_url.rstrip('/')}/audio/transcriptions", body,
            _headers(target.provider, target.api_key, ctype), timeout=timeout,
        )
    except ApiError as exc:
        raise explain(exc, target.service) from None


def transcribe(target, wav_path, language="", prompt="", timeout=300):
    data = _transcribe_request(
        target, wav_path, language, prompt, "json", timeout=timeout
    )
    text = (data.get("text") or "").strip()
    if not text:
        raise ApiError(t("Transcript came back empty."))
    return text


def transcribe_segments(target, wav_path, language="", prompt="", timeout=300):
    """[(start_seconds, end_seconds, text)] using whisper-1's verbose response."""
    data = _transcribe_request(
        target._replace(model=timestamp_model(target.provider)),
        wav_path, language, prompt, "verbose_json",
        granularity="segment", timeout=timeout,
    )
    segments = data.get("segments") or []
    out = []
    for seg in segments:
        text = (seg.get("text") or "").strip()
        if text:
            start = float(seg.get("start") or 0.0)
            end = float(seg.get("end") or 0.0)
            out.append((start, max(end, start), text))
    if not out:
        text = (data.get("text") or "").strip()
        if not text:
            raise ApiError(t("Transcript came back empty."))
        out = [(0.0, 0.0, text)]
    return out


def cleanup(text, api_key, model, system_prompt, base_url=OPENROUTER_URL, timeout=180):
    if not api_key:
        raise ApiError(t("{service} API key is empty. Add it in Settings.",
                         service="OpenRouter"))
    payload = {
        "model": model,
        "temperature": 0,
        "messages": [
            {"role": "system", "content": system_prompt},
            {"role": "user", "content": f"<transcript>\n{text}\n</transcript>"},
        ],
    }
    try:
        data = _request(
            f"{base_url.rstrip('/')}/chat/completions",
            json.dumps(payload).encode("utf-8"),
            _headers("openrouter", api_key, "application/json"),
            timeout=timeout,
        )
    except ApiError as exc:
        raise explain(exc, "OpenRouter") from None
    choices = data.get("choices") or []
    if not choices:
        raise ApiError(_extract_error(json.dumps(data)))
    content = ((choices[0].get("message") or {}).get("content") or "").strip()
    if not content:
        raise ApiError(t("The cleanup model returned an empty reply."))
    return content


def _get_json(url, headers, timeout=20):
    req = urllib.request.Request(url, headers=headers)
    try:
        with urllib.request.urlopen(req, timeout=timeout) as resp:
            return json.loads(resp.read().decode("utf-8"))
    except urllib.error.HTTPError as exc:
        body = exc.read().decode("utf-8", "replace")
        raise ApiError(f"HTTP {exc.code}: {_extract_error(body)}", exc.code) from exc
    except urllib.error.URLError as exc:
        raise ApiError(t("Could not connect: {reason}", reason=exc.reason)) from exc
    except json.JSONDecodeError as exc:
        raise ApiError(t("Could not parse the response: {error}", error=exc)) from exc


def openrouter_key_status(api_key):
    """Check the key against OpenRouter's own /key endpoint."""
    if not api_key:
        raise ApiError(t("{service} API key is empty. Add it in Settings.",
                         service="OpenRouter"))
    try:
        data = _get_json(f"{OPENROUTER_URL}/key",
                         {"Authorization": f"Bearer {api_key}", "User-Agent": USER_AGENT})
    except ApiError as exc:
        raise explain(exc, "OpenRouter") from None
    info = data.get("data") or {}
    limit, usage = info.get("limit"), info.get("usage")
    if limit is None:
        return t("Key works, no spending limit set.")
    return t("Key works. Used {usage} of {limit}.",
             usage=round(float(usage or 0), 3), limit=round(float(limit), 3))


def openrouter_models(api_key="", transcription=False):
    """Model ids available on OpenRouter (no key required).

    `transcription` narrows the list to the speech-to-text models, the only ones
    /audio/transcriptions accepts. The filter is applied again on the result,
    because a query parameter the API stops honouring would otherwise quietly
    hand back all several hundred models.
    """
    url = f"{OPENROUTER_URL}/models"
    if transcription:
        url += "?output_modalities=transcription"
    headers = {"User-Agent": USER_AGENT}
    if api_key:
        headers["Authorization"] = f"Bearer {api_key}"
    models = _get_json(url, headers).get("data", [])
    if transcription:
        models = [m for m in models
                  if "transcription" in (m.get("architecture") or {}).get(
                      "output_modalities", [])]
    return sorted(m["id"] for m in models if m.get("id"))


def openai_models(api_key, base_url=OPENAI_URL):
    if not api_key:
        raise ApiError(t("{service} API key is empty. Add it in Settings.",
                         service="OpenAI"))
    try:
        data = _get_json(
            f"{base_url.rstrip('/')}/models",
            {"Authorization": f"Bearer {api_key}", "User-Agent": USER_AGENT},
        )
    except ApiError as exc:
        raise explain(exc, "OpenAI") from None
    ids = [m["id"] for m in data.get("data", []) if m.get("id")]
    audio = [i for i in ids if "transcribe" in i or "whisper" in i]
    return sorted(audio or ids)