from __future__ import annotations

import asyncio
import hashlib
import os
import platform
import uuid
from collections.abc import AsyncIterator
from typing import Any

import httpx

from .streaming import StreamParser, parse_sse_stream
from .types import AssistantMessage, StreamChunk, ToolHandler, ToolResult, ToolUse

MODELS: dict[str, dict[str, str]] = {
    "claude-haiku-4-5-20251001": {"family": "haiku", "display": "Haiku 4.5"},
    "claude-sonnet-4-6": {"family": "sonnet", "display": "Sonnet 4.6"},
    "claude-opus-4-6": {"family": "opus", "display": "Opus 4.6"},
}

BETA_BASE = "oauth-2025-04-20,interleaved-thinking-2025-05-14,prompt-caching-scope-2026-01-05,claude-code-20250219"
BETA_ADAPTIVE = "claude-code-20250219,oauth-2025-04-20,interleaved-thinking-2025-05-14,prompt-caching-scope-2026-01-05,effort-2025-11-24,adaptive-thinking-2026-01-28"


def _supports_adaptive(model: str) -> bool:
    m = model.lower()
    return "sonnet" in m or "opus" in m


class ChatClient:
    BASE_URL = "https://api.anthropic.com"
    API_VERSION = "2023-06-01"

    @staticmethod
    def list_models() -> dict[str, dict[str, str]]:
        return dict(MODELS)

    def __init__(
        self,
        api_key: str | None = None,
        model: str = "claude-sonnet-4-6",
        max_tokens: int = 8192,
        system: str | None = None,
        timeout: float = 300.0,
        tools: list[dict[str, Any]] | None = None,
        max_retries: int = 3,
        backoff_factor: float = 1.0,
    ):
        self.api_key = (
            api_key or os.getenv("ANTHROPIC_API_KEY") or os.getenv("CLAUDE_CODE_OAUTH_TOKEN")
        )
        if not self.api_key:
            raise ValueError("API key required: set ANTHROPIC_API_KEY or CLAUDE_CODE_OAUTH_TOKEN")
        self.model = model
        self.max_tokens = max_tokens
        self.system = system
        self.tools = tools
        self.max_retries = max_retries
        self.backoff_factor = backoff_factor
        self.client = httpx.AsyncClient(http2=True, timeout=timeout)
        self._device_id = hashlib.sha256(platform.node().encode()).hexdigest()
        self._account_uuid = os.getenv("CLAUDE_ACCOUNT_UUID") or str(uuid.uuid4())
        self._session_id = str(uuid.uuid4())

    def _headers(self, model: str | None = None) -> dict[str, str]:
        m = model or self.model
        beta = BETA_ADAPTIVE if _supports_adaptive(m) else BETA_BASE
        return {
            "accept": "application/json",
            "accept-language": "*",
            "anthropic-beta": beta,
            "anthropic-dangerous-direct-browser-access": "true",
            "anthropic-version": self.API_VERSION,
            "authorization": f"Bearer {self.api_key}",
            "content-type": "application/json",
            "sec-fetch-mode": "cors",
            "user-agent": "claude-cli/2.1.63 (external, sdk-cli)",
            "x-app": "cli",
            "x-stainless-arch": "x64",
            "x-stainless-lang": "js",
            "x-stainless-os": "Linux",
            "x-stainless-package-version": "0.74.0",
            "x-stainless-retry-count": "0",
            "x-stainless-runtime": "node",
            "x-stainless-runtime-version": "v20.20.0",
            "x-stainless-timeout": "600",
        }

    def _metadata(self) -> dict[str, str]:
        return {
            "user_id": f"user_{self._device_id}_account_{self._account_uuid}_session_{self._session_id}"
        }

    @staticmethod
    def _normalize_messages(
        messages: str | list[dict[str, Any]],
    ) -> list[dict[str, Any]]:
        if isinstance(messages, str):
            return [{"role": "user", "content": messages}]
        return list(messages)

    def _body(
        self,
        messages: list[dict[str, Any]],
        stream: bool,
        max_tokens: int | None = None,
        system: str | None = None,
        model: str | None = None,
        tools: list[dict[str, Any]] | None = None,
    ) -> dict[str, Any]:
        m = model or self.model
        body: dict[str, Any] = {
            "model": m,
            "max_tokens": max_tokens or self.max_tokens,
            "messages": messages,
            "metadata": self._metadata(),
            "stream": stream,
        }
        sys_text = system or self.system
        if sys_text:
            body["system"] = sys_text
        effective_tools = tools or self.tools
        if effective_tools:
            body["tools"] = effective_tools
        return body

    async def chat(
        self,
        messages: str | list[dict[str, Any]],
        *,
        model: str | None = None,
        max_tokens: int | None = None,
        system: str | None = None,
        tools: list[dict[str, Any]] | None = None,
    ) -> AssistantMessage:
        msgs = self._normalize_messages(messages)
        m = model or self.model
        body = self._body(
            msgs, stream=False, max_tokens=max_tokens, system=system, model=m, tools=tools
        )
        url = f"{self.BASE_URL}/v1/messages"

        last_error: Exception | None = None
        backoff = self.backoff_factor
        for attempt in range(self.max_retries):
            try:
                resp = await self.client.post(url, headers=self._headers(m), json=body)
                resp.raise_for_status()
                return AssistantMessage.model_validate(resp.json())
            except (httpx.ConnectError, httpx.ConnectTimeout) as e:
                last_error = e
                if attempt < self.max_retries - 1:
                    await asyncio.sleep(backoff)
                    backoff *= 2
        raise last_error  # type: ignore[misc]

    async def stream(
        self,
        messages: str | list[dict[str, Any]],
        *,
        model: str | None = None,
        max_tokens: int | None = None,
        system: str | None = None,
        tools: list[dict[str, Any]] | None = None,
    ) -> AsyncIterator[StreamChunk]:
        msgs = self._normalize_messages(messages)
        m = model or self.model
        body = self._body(
            msgs, stream=True, max_tokens=max_tokens, system=system, model=m, tools=tools
        )
        url = f"{self.BASE_URL}/v1/messages"

        last_error = None
        backoff = self.backoff_factor
        for attempt in range(self.max_retries):
            try:
                async for chunk in parse_sse_stream(
                    self.client, "POST", url, self._headers(m), body
                ):
                    yield chunk
                return
            except (httpx.ConnectError, httpx.ConnectTimeout) as e:
                last_error = e
                if attempt < self.max_retries - 1:
                    await asyncio.sleep(backoff)
                    backoff *= 2
        if last_error:
            raise last_error

    async def collect(
        self,
        messages: str | list[dict[str, Any]],
        *,
        model: str | None = None,
        max_tokens: int | None = None,
        system: str | None = None,
        tools: list[dict[str, Any]] | None = None,
    ) -> str:
        parser = StreamParser()
        async for chunk in self.stream(
            messages, model=model, max_tokens=max_tokens, system=system, tools=tools
        ):
            parser.add_chunk(chunk)
        msg = parser.to_dict()
        parts = []
        for block in msg.get("content", []):
            if block.get("type") == "text":
                parts.append(block["text"])
        return "".join(parts)

    async def run(
        self,
        messages: str | list[dict[str, Any]],
        *,
        tools: list[dict[str, Any]] | None = None,
        tool_handler: ToolHandler,
        model: str | None = None,
        max_tokens: int | None = None,
        system: str | None = None,
        max_turns: int = 10,
    ) -> AssistantMessage:
        msgs = self._normalize_messages(messages)
        for _ in range(max_turns):
            resp = await self.chat(
                msgs,
                model=model,
                max_tokens=max_tokens,
                system=system,
                tools=tools,
            )
            if not resp.has_tool_use:
                return resp
            msgs.append({"role": "assistant", "content": resp.content})
            tool_results = []
            for tc in resp.tool_calls:
                try:
                    result = await tool_handler(tc.name, tc.input)
                    tool_results.append(
                        ToolResult(
                            type="tool_result",
                            tool_use_id=tc.id,
                            content=result,
                            is_error=False,
                        )
                    )
                except Exception as exc:
                    tool_results.append(
                        ToolResult(
                            type="tool_result",
                            tool_use_id=tc.id,
                            content=str(exc),
                            is_error=True,
                        )
                    )
            msgs.append(
                {
                    "role": "user",
                    "content": [r.model_dump() for r in tool_results],
                }
            )
        return resp

    async def run_stream(
        self,
        messages: str | list[dict[str, Any]],
        *,
        tools: list[dict[str, Any]] | None = None,
        tool_handler: ToolHandler,
        model: str | None = None,
        max_tokens: int | None = None,
        system: str | None = None,
        max_turns: int = 10,
    ) -> AsyncIterator[StreamChunk | ToolUse | ToolResult]:
        msgs = self._normalize_messages(messages)
        for _ in range(max_turns):
            parser = StreamParser()
            async for chunk in self.stream(
                msgs,
                model=model,
                max_tokens=max_tokens,
                system=system,
                tools=tools,
            ):
                parser.add_chunk(chunk)
                yield chunk
            msg_dict = parser.to_dict()
            resp = AssistantMessage.model_validate(msg_dict)
            if not resp.has_tool_use:
                return
            msgs.append({"role": "assistant", "content": resp.content})
            tool_results = []
            for tc in resp.tool_calls:
                yield tc
                try:
                    result = await tool_handler(tc.name, tc.input)
                    tr = ToolResult(
                        type="tool_result",
                        tool_use_id=tc.id,
                        content=result,
                        is_error=False,
                    )
                except Exception as exc:
                    tr = ToolResult(
                        type="tool_result",
                        tool_use_id=tc.id,
                        content=str(exc),
                        is_error=True,
                    )
                yield tr
                tool_results.append(tr)
            msgs.append(
                {
                    "role": "user",
                    "content": [r.model_dump() for r in tool_results],
                }
            )

    async def close(self):
        await self.client.aclose()

    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        await self.close()