"""OpenAI-compatible provider for all non-Anthropic LLM APIs."""

from __future__ import annotations

import hashlib
import os
import secrets
import string
import uuid
from collections.abc import Awaitable, Callable
from typing import TYPE_CHECKING, Any

import json_repair
from openai import AsyncOpenAI

from nanobot.providers.base import LLMProvider, LLMResponse, ToolCallRequest

if TYPE_CHECKING:
    from nanobot.providers.registry import ProviderSpec

_ALLOWED_MSG_KEYS = frozenset({
    "role", "content", "tool_calls", "tool_call_id", "name",
    "reasoning_content", "extra_content",
})
_ALNUM = string.ascii_letters + string.digits

_STANDARD_TC_KEYS = frozenset({"id", "type", "index", "function"})
_STANDARD_FN_KEYS = frozenset({"name", "arguments"})
_DEFAULT_OPENROUTER_HEADERS = {
    "HTTP-Referer": "https://github.com/HKUDS/nanobot",
    "X-OpenRouter-Title": "nanobot",
    "X-OpenRouter-Categories": "cli-agent,personal-agent",
}


def _short_tool_id() -> str:
    """9-char alphanumeric ID compatible with all providers (incl. Mistral)."""
    return "".join(secrets.choice(_ALNUM) for _ in range(9))


def _get(obj: Any, key: str) -> Any:
    """Get a value from dict or object attribute, returning None if absent."""
    if isinstance(obj, dict):
        return obj.get(key)
    return getattr(obj, key, None)


def _coerce_dict(value: Any) -> dict[str, Any] | None:
    """Try to coerce *value* to a dict; return None if not possible or empty."""
    if value is None:
        return None
    if isinstance(value, dict):
        return value if value else None
    model_dump = getattr(value, "model_dump", None)
    if callable(model_dump):
        dumped = model_dump()
        if isinstance(dumped, dict) and dumped:
            return dumped
    return None


def _extract_tc_extras(tc: Any) -> tuple[
    dict[str, Any] | None,
    dict[str, Any] | None,
    dict[str, Any] | None,
]:
    """Extract (extra_content, provider_specific_fields, fn_provider_specific_fields).

    Works for both SDK objects and dicts.  Captures Gemini ``extra_content``
    verbatim and any non-standard keys on the tool-call / function.
    """
    extra_content = _coerce_dict(_get(tc, "extra_content"))

    tc_dict = _coerce_dict(tc)
    prov = None
    fn_prov = None
    if tc_dict is not None:
        leftover = {k: v for k, v in tc_dict.items()
                    if k not in _STANDARD_TC_KEYS and k != "extra_content" and v is not None}
        if leftover:
            prov = leftover
        fn = _coerce_dict(tc_dict.get("function"))
        if fn is not None:
            fn_leftover = {k: v for k, v in fn.items()
                          if k not in _STANDARD_FN_KEYS and v is not None}
            if fn_leftover:
                fn_prov = fn_leftover
    else:
        prov = _coerce_dict(_get(tc, "provider_specific_fields"))
        fn_obj = _get(tc, "function")
        if fn_obj is not None:
            fn_prov = _coerce_dict(_get(fn_obj, "provider_specific_fields"))

    return extra_content, prov, fn_prov


def _uses_openrouter_attribution(spec: "ProviderSpec | None", api_base: str | None) -> bool:
    """Apply Nanobot attribution headers to OpenRouter requests by default."""
    if spec and spec.name == "openrouter":
        return True
    return bool(api_base and "openrouter" in api_base.lower())


class OpenAICompatProvider(LLMProvider):
    """Unified provider for all OpenAI-compatible APIs.

    Receives a resolved ``ProviderSpec`` from the caller — no internal
    registry lookups needed.
    """

    def __init__(
        self,
        api_key: str | None = None,
        api_base: str | None = None,
        default_model: str = "gpt-4o",
        extra_headers: dict[str, str] | None = None,
        spec: ProviderSpec | None = None,
    ):
        super().__init__(api_key, api_base)
        self.default_model = default_model
        self.extra_headers = extra_headers or {}
        self._spec = spec

        if api_key and spec and spec.env_key:
            self._setup_env(api_key, api_base)

        effective_base = api_base or (spec.default_api_base if spec else None) or None
        default_headers = {"x-session-affinity": uuid.uuid4().hex}
        if _uses_openrouter_attribution(spec, effective_base):
            default_headers.update(_DEFAULT_OPENROUTER_HEADERS)
        if extra_headers:
            default_headers.update(extra_headers)

        self._client = AsyncOpenAI(
            api_key=api_key or "no-key",
            base_url=effective_base,
            default_headers=default_headers,
        )

    def _setup_env(self, api_key: str, api_base: str | None) -> None:
        """Set environment variables based on provider spec."""
        spec = self._spec
        if not spec or not spec.env_key:
            return
        if spec.is_gateway:
            os.environ[spec.env_key] = api_key
        else:
            os.environ.setdefault(spec.env_key, api_key)
        effective_base = api_base or spec.default_api_base
        for env_name, env_val in spec.env_extras:
            resolved = env_val.replace("{api_key}", api_key).replace("{api_base}", effective_base)
            os.environ.setdefault(env_name, resolved)

    @staticmethod
    def _apply_cache_control(
        messages: list[dict[str, Any]],
        tools: list[dict[str, Any]] | None,
    ) -> tuple[list[dict[str, Any]], list[dict[str, Any]] | None]:
        """Inject cache_control markers for prompt caching."""
        cache_marker = {"type": "ephemeral"}
        new_messages = list(messages)

        def _mark(msg: dict[str, Any]) -> dict[str, Any]:
            content = msg.get("content")
            if isinstance(content, str):
                return {**msg, "content": [
                    {"type": "text", "text": content, "cache_control": cache_marker},
                ]}
            if isinstance(content, list) and content:
                nc = list(content)
                nc[-1] = {**nc[-1], "cache_control": cache_marker}
                return {**msg, "content": nc}
            return msg

        if new_messages and new_messages[0].get("role") == "system":
            new_messages[0] = _mark(new_messages[0])
        if len(new_messages) >= 3:
            new_messages[-2] = _mark(new_messages[-2])

        new_tools = tools
        if tools:
            new_tools = list(tools)
            new_tools[-1] = {**new_tools[-1], "cache_control": cache_marker}
        return new_messages, new_tools

    @staticmethod
    def _normalize_tool_call_id(tool_call_id: Any) -> Any:
        """Normalize to a provider-safe 9-char alphanumeric form."""
        if not isinstance(tool_call_id, str):
            return tool_call_id
        if len(tool_call_id) == 9 and tool_call_id.isalnum():
            return tool_call_id
        return hashlib.sha1(tool_call_id.encode()).hexdigest()[:9]

    def _sanitize_messages(self, messages: list[dict[str, Any]]) -> list[dict[str, Any]]:
        """Strip non-standard keys, normalize tool_call IDs."""
        sanitized = LLMProvider._sanitize_request_messages(messages, _ALLOWED_MSG_KEYS)
        id_map: dict[str, str] = {}

        def map_id(value: Any) -> Any:
            if not isinstance(value, str):
                return value
            return id_map.setdefault(value, self._normalize_tool_call_id(value))

        for clean in sanitized:
            if isinstance(clean.get("tool_calls"), list):
                normalized = []
                for tc in clean["tool_calls"]:
                    if not isinstance(tc, dict):
                        normalized.append(tc)
                        continue
                    tc_clean = dict(tc)
                    tc_clean["id"] = map_id(tc_clean.get("id"))
                    normalized.append(tc_clean)
                clean["tool_calls"] = normalized
            if "tool_call_id" in clean and clean["tool_call_id"]:
                clean["tool_call_id"] = map_id(clean["tool_call_id"])
        return sanitized

    # ------------------------------------------------------------------
    # Build kwargs
    # ------------------------------------------------------------------

    def _build_kwargs(
        self,
        messages: list[dict[str, Any]],
        tools: list[dict[str, Any]] | None,
        model: str | None,
        max_tokens: int,
        temperature: float,
        reasoning_effort: str | None,
        tool_choice: str | dict[str, Any] | None,
    ) -> dict[str, Any]:
        model_name = model or self.default_model
        spec = self._spec

        if spec and spec.supports_prompt_caching:
            messages, tools = self._apply_cache_control(messages, tools)

        if spec and spec.strip_model_prefix:
            model_name = model_name.split("/")[-1]

        kwargs: dict[str, Any] = {
            "model": model_name,
            "messages": self._sanitize_messages(self._sanitize_empty_content(messages)),
            "temperature": temperature,
        }

        if spec and getattr(spec, "supports_max_completion_tokens", False):
            kwargs["max_completion_tokens"] = max(1, max_tokens)
        else:
            kwargs["max_tokens"] = max(1, max_tokens)

        if spec:
            model_lower = model_name.lower()
            for pattern, overrides in spec.model_overrides:
                if pattern in model_lower:
                    kwargs.update(overrides)
                    break

        if reasoning_effort:
            kwargs["reasoning_effort"] = reasoning_effort

        if tools:
            kwargs["tools"] = tools
            kwargs["tool_choice"] = tool_choice or "auto"

        return kwargs

    # ------------------------------------------------------------------
    # Response parsing
    # ------------------------------------------------------------------

    @staticmethod
    def _maybe_mapping(value: Any) -> dict[str, Any] | None:
        if isinstance(value, dict):
            return value
        model_dump = getattr(value, "model_dump", None)
        if callable(model_dump):
            dumped = model_dump()
            if isinstance(dumped, dict):
                return dumped
        return None

    @classmethod
    def _extract_text_content(cls, value: Any) -> str | None:
        if value is None:
            return None
        if isinstance(value, str):
            return value
        if isinstance(value, list):
            parts: list[str] = []
            for item in value:
                item_map = cls._maybe_mapping(item)
                if item_map:
                    text = item_map.get("text")
                    if isinstance(text, str):
                        parts.append(text)
                        continue
                text = getattr(item, "text", None)
                if isinstance(text, str):
                    parts.append(text)
                    continue
                if isinstance(item, str):
                    parts.append(item)
            return "".join(parts) or None
        return str(value)

    @classmethod
    def _extract_usage(cls, response: Any) -> dict[str, int]:
        usage_obj = None
        response_map = cls._maybe_mapping(response)
        if response_map is not None:
            usage_obj = response_map.get("usage")
        elif hasattr(response, "usage") and response.usage:
            usage_obj = response.usage

        usage_map = cls._maybe_mapping(usage_obj)
        if usage_map is not None:
            return {
                "prompt_tokens": int(usage_map.get("prompt_tokens") or 0),
                "completion_tokens": int(usage_map.get("completion_tokens") or 0),
                "total_tokens": int(usage_map.get("total_tokens") or 0),
            }

        if usage_obj:
            return {
                "prompt_tokens": getattr(usage_obj, "prompt_tokens", 0) or 0,
                "completion_tokens": getattr(usage_obj, "completion_tokens", 0) or 0,
                "total_tokens": getattr(usage_obj, "total_tokens", 0) or 0,
            }
        return {}

    def _parse(self, response: Any) -> LLMResponse:
        if isinstance(response, str):
            return LLMResponse(content=response, finish_reason="stop")

        response_map = self._maybe_mapping(response)
        if response_map is not None:
            choices = response_map.get("choices") or []
            if not choices:
                content = self._extract_text_content(
                    response_map.get("content") or response_map.get("output_text")
                )
                if content is not None:
                    return LLMResponse(
                        content=content,
                        finish_reason=str(response_map.get("finish_reason") or "stop"),
                        usage=self._extract_usage(response_map),
                    )
                return LLMResponse(content="Error: API returned empty choices.", finish_reason="error")

            choice0 = self._maybe_mapping(choices[0]) or {}
            msg0 = self._maybe_mapping(choice0.get("message")) or {}
            content = self._extract_text_content(msg0.get("content"))
            finish_reason = str(choice0.get("finish_reason") or "stop")

            raw_tool_calls: list[Any] = []
            reasoning_content = msg0.get("reasoning_content")
            for ch in choices:
                ch_map = self._maybe_mapping(ch) or {}
                m = self._maybe_mapping(ch_map.get("message")) or {}
                tool_calls = m.get("tool_calls")
                if isinstance(tool_calls, list) and tool_calls:
                    raw_tool_calls.extend(tool_calls)
                    if ch_map.get("finish_reason") in ("tool_calls", "stop"):
                        finish_reason = str(ch_map["finish_reason"])
                if not content:
                    content = self._extract_text_content(m.get("content"))
                if not reasoning_content:
                    reasoning_content = m.get("reasoning_content")

            parsed_tool_calls = []
            for tc in raw_tool_calls:
                tc_map = self._maybe_mapping(tc) or {}
                fn = self._maybe_mapping(tc_map.get("function")) or {}
                args = fn.get("arguments", {})
                if isinstance(args, str):
                    args = json_repair.loads(args)
                ec, prov, fn_prov = _extract_tc_extras(tc)
                parsed_tool_calls.append(ToolCallRequest(
                    id=_short_tool_id(),
                    name=str(fn.get("name") or ""),
                    arguments=args if isinstance(args, dict) else {},
                    extra_content=ec,
                    provider_specific_fields=prov,
                    function_provider_specific_fields=fn_prov,
                ))

            return LLMResponse(
                content=content,
                tool_calls=parsed_tool_calls,
                finish_reason=finish_reason,
                usage=self._extract_usage(response_map),
                reasoning_content=reasoning_content if isinstance(reasoning_content, str) else None,
            )

        if not response.choices:
            return LLMResponse(content="Error: API returned empty choices.", finish_reason="error")

        choice = response.choices[0]
        msg = choice.message
        content = msg.content
        finish_reason = choice.finish_reason

        raw_tool_calls: list[Any] = []
        for ch in response.choices:
            m = ch.message
            if hasattr(m, "tool_calls") and m.tool_calls:
                raw_tool_calls.extend(m.tool_calls)
                if ch.finish_reason in ("tool_calls", "stop"):
                    finish_reason = ch.finish_reason
            if not content and m.content:
                content = m.content

        tool_calls = []
        for tc in raw_tool_calls:
            args = tc.function.arguments
            if isinstance(args, str):
                args = json_repair.loads(args)
            ec, prov, fn_prov = _extract_tc_extras(tc)
            tool_calls.append(ToolCallRequest(
                id=_short_tool_id(),
                name=tc.function.name,
                arguments=args,
                extra_content=ec,
                provider_specific_fields=prov,
                function_provider_specific_fields=fn_prov,
            ))

        return LLMResponse(
            content=content,
            tool_calls=tool_calls,
            finish_reason=finish_reason or "stop",
            usage=self._extract_usage(response),
            reasoning_content=getattr(msg, "reasoning_content", None) or None,
        )

    @classmethod
    def _parse_chunks(cls, chunks: list[Any]) -> LLMResponse:
        content_parts: list[str] = []
        tc_bufs: dict[int, dict[str, Any]] = {}
        finish_reason = "stop"
        usage: dict[str, int] = {}

        def _accum_tc(tc: Any, idx_hint: int) -> None:
            """Accumulate one streaming tool-call delta into *tc_bufs*."""
            tc_index: int = _get(tc, "index") if _get(tc, "index") is not None else idx_hint
            buf = tc_bufs.setdefault(tc_index, {
                "id": "", "name": "", "arguments": "",
                "extra_content": None, "prov": None, "fn_prov": None,
            })
            tc_id = _get(tc, "id")
            if tc_id:
                buf["id"] = str(tc_id)
            fn = _get(tc, "function")
            if fn is not None:
                fn_name = _get(fn, "name")
                if fn_name:
                    buf["name"] = str(fn_name)
                fn_args = _get(fn, "arguments")
                if fn_args:
                    buf["arguments"] += str(fn_args)
            ec, prov, fn_prov = _extract_tc_extras(tc)
            if ec:
                buf["extra_content"] = ec
            if prov:
                buf["prov"] = prov
            if fn_prov:
                buf["fn_prov"] = fn_prov

        for chunk in chunks:
            if isinstance(chunk, str):
                content_parts.append(chunk)
                continue

            chunk_map = cls._maybe_mapping(chunk)
            if chunk_map is not None:
                choices = chunk_map.get("choices") or []
                if not choices:
                    usage = cls._extract_usage(chunk_map) or usage
                    text = cls._extract_text_content(
                        chunk_map.get("content") or chunk_map.get("output_text")
                    )
                    if text:
                        content_parts.append(text)
                    continue
                choice = cls._maybe_mapping(choices[0]) or {}
                if choice.get("finish_reason"):
                    finish_reason = str(choice["finish_reason"])
                delta = cls._maybe_mapping(choice.get("delta")) or {}
                text = cls._extract_text_content(delta.get("content"))
                if text:
                    content_parts.append(text)
                for idx, tc in enumerate(delta.get("tool_calls") or []):
                    _accum_tc(tc, idx)
                usage = cls._extract_usage(chunk_map) or usage
                continue

            if not chunk.choices:
                usage = cls._extract_usage(chunk) or usage
                continue
            choice = chunk.choices[0]
            if choice.finish_reason:
                finish_reason = choice.finish_reason
            delta = choice.delta
            if delta and delta.content:
                content_parts.append(delta.content)
            for tc in (delta.tool_calls or []) if delta else []:
                _accum_tc(tc, getattr(tc, "index", 0))

        return LLMResponse(
            content="".join(content_parts) or None,
            tool_calls=[
                ToolCallRequest(
                    id=b["id"] or _short_tool_id(),
                    name=b["name"],
                    arguments=json_repair.loads(b["arguments"]) if b["arguments"] else {},
                    extra_content=b.get("extra_content"),
                    provider_specific_fields=b.get("prov"),
                    function_provider_specific_fields=b.get("fn_prov"),
                )
                for b in tc_bufs.values()
            ],
            finish_reason=finish_reason,
            usage=usage,
        )

    @staticmethod
    def _handle_error(e: Exception) -> LLMResponse:
        body = getattr(e, "doc", None) or getattr(getattr(e, "response", None), "text", None)
        msg = f"Error: {body.strip()[:500]}" if body and body.strip() else f"Error calling LLM: {e}"
        return LLMResponse(content=msg, finish_reason="error")

    # ------------------------------------------------------------------
    # Public API
    # ------------------------------------------------------------------

    async def chat(
        self,
        messages: list[dict[str, Any]],
        tools: list[dict[str, Any]] | None = None,
        model: str | None = None,
        max_tokens: int = 4096,
        temperature: float = 0.7,
        reasoning_effort: str | None = None,
        tool_choice: str | dict[str, Any] | None = None,
    ) -> LLMResponse:
        kwargs = self._build_kwargs(
            messages, tools, model, max_tokens, temperature,
            reasoning_effort, tool_choice,
        )
        try:
            return self._parse(await self._client.chat.completions.create(**kwargs))
        except Exception as e:
            return self._handle_error(e)

    async def chat_stream(
        self,
        messages: list[dict[str, Any]],
        tools: list[dict[str, Any]] | None = None,
        model: str | None = None,
        max_tokens: int = 4096,
        temperature: float = 0.7,
        reasoning_effort: str | None = None,
        tool_choice: str | dict[str, Any] | None = None,
        on_content_delta: Callable[[str], Awaitable[None]] | None = None,
    ) -> LLMResponse:
        kwargs = self._build_kwargs(
            messages, tools, model, max_tokens, temperature,
            reasoning_effort, tool_choice,
        )
        kwargs["stream"] = True
        kwargs["stream_options"] = {"include_usage": True}
        try:
            stream = await self._client.chat.completions.create(**kwargs)
            chunks: list[Any] = []
            async for chunk in stream:
                chunks.append(chunk)
                if on_content_delta and chunk.choices:
                    text = getattr(chunk.choices[0].delta, "content", None)
                    if text:
                        await on_content_delta(text)
            return self._parse_chunks(chunks)
        except Exception as e:
            return self._handle_error(e)

    def get_default_model(self) -> str:
        return self.default_model
