"""Thinking / Extended Thinking helpers.

This project implements "thinking" at the proxy layer by:
1) Making a separate Kiro request to generate internal reasoning text.
2) Injecting that reasoning back into the main user prompt (hidden) to improve quality.
3) Optionally returning the reasoning to clients in protocol-appropriate formats.

Notes:
- Kiro's upstream API doesn't expose a native "thinking budget" knob, so `budget_tokens`
  is enforced only via prompt instructions (best-effort).
- If the client does not provide a budget, we treat it as "unlimited" (no prompt limit).
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import Any, AsyncIterator, Optional

import json

import httpx

from ..config import KIRO_API_URL
from ..kiro_api import build_kiro_request, parse_event_stream


@dataclass(frozen=True)
class ThinkingConfig:
    enabled: bool
    budget_tokens: Optional[int] = None  # None == unlimited


def _coerce_bool(value: Any) -> Optional[bool]:
    if isinstance(value, bool):
        return value
    if isinstance(value, (int, float)):
        return bool(value)
    if isinstance(value, str):
        v = value.strip().lower()
        if v in {"true", "1", "yes", "y", "on", "enabled"}:
            return True
        if v in {"false", "0", "no", "n", "off", "disabled"}:
            return False
    return None


def _coerce_int(value: Any) -> Optional[int]:
    if value is None:
        return None
    if isinstance(value, bool):
        return None
    if isinstance(value, int):
        return value
    if isinstance(value, float):
        return int(value)
    if isinstance(value, str):
        v = value.strip()
        if not v:
            return None
        try:
            return int(v)
        except ValueError:
            return None
    return None


def normalize_thinking_config(raw: Any) -> ThinkingConfig:
    """Normalize multiple "thinking" shapes into a single config.

    Supported shapes (best-effort):
    - None / missing: disabled
    - bool: enabled/disabled
    - str: "enabled"/"disabled"
    - dict:
        - {"type": "enabled", "budget_tokens": 20000} (Anthropic style)
        - {"thinking_type": "enabled", "budget_tokens": 20000} (legacy)
        - {"enabled": true, "budget_tokens": 20000}
        - {"includeThoughts": true, "thinkingBudget": 20000} (Gemini-ish)
    """
    if raw is None:
        return ThinkingConfig(enabled=False, budget_tokens=None)

    bool_value = _coerce_bool(raw)
    if bool_value is not None and not isinstance(raw, dict):
        return ThinkingConfig(enabled=bool_value, budget_tokens=None)

    if isinstance(raw, dict):
        mode = raw.get("type") or raw.get("thinking_type") or raw.get("mode")
        enabled = None
        if isinstance(mode, str):
            enabled = _coerce_bool(mode)
        if enabled is None:
            enabled = _coerce_bool(raw.get("enabled"))
        if enabled is None:
            enabled = _coerce_bool(raw.get("includeThoughts") or raw.get("include_thoughts"))
        if enabled is None:
            enabled = False

        budget_tokens = None
        for key in (
            "budget_tokens",
            "budgetTokens",
            "thinkingBudget",
            "thinking_budget",
            "max_thinking_length",
            "maxThinkingLength",
        ):
            if key in raw:
                budget_tokens = _coerce_int(raw.get(key))
                break
        if budget_tokens is not None and budget_tokens <= 0:
            budget_tokens = None

        return ThinkingConfig(enabled=bool(enabled), budget_tokens=budget_tokens)

    if isinstance(raw, str):
        enabled = _coerce_bool(raw)
        return ThinkingConfig(enabled=bool(enabled), budget_tokens=None)

    return ThinkingConfig(enabled=False, budget_tokens=None)


def map_openai_reasoning_effort_to_budget(effort: Any) -> Optional[int]:
    """Map OpenAI-style reasoning effort into a best-effort budget.

    We keep this generous; if effort is "high", treat as unlimited.
    """
    if not isinstance(effort, str):
        return None
    v = effort.strip().lower()
    if v in {"high"}:
        return None
    if v in {"medium"}:
        return 20000
    if v in {"low"}:
        return 10000
    return None


def extract_thinking_config_from_openai_body(body: dict) -> tuple[ThinkingConfig, bool]:
    """Extract thinking config from OpenAI ChatCompletions/Responses-style bodies."""
    if not isinstance(body, dict):
        return ThinkingConfig(False, None), False

    if "thinking" in body:
        return normalize_thinking_config(body.get("thinking")), True

    # OpenAI Responses API style
    reasoning = body.get("reasoning")
    if "reasoning" in body:
        if isinstance(reasoning, dict):
            effort = reasoning.get("effort")
            if isinstance(effort, str) and effort.strip().lower() in {"low", "medium", "high"}:
                return ThinkingConfig(True, map_openai_reasoning_effort_to_budget(effort)), True
        cfg = normalize_thinking_config(reasoning)
        return cfg, True

    effort = body.get("reasoning_effort")
    if "reasoning_effort" in body and isinstance(effort, str) and effort.strip().lower() in {"low", "medium", "high"}:
        return ThinkingConfig(True, map_openai_reasoning_effort_to_budget(effort)), True

    return ThinkingConfig(False, None), False


def extract_thinking_config_from_gemini_body(body: dict) -> tuple[ThinkingConfig, bool]:
    """Extract thinking config from Gemini generateContent bodies (best-effort)."""
    if not isinstance(body, dict):
        return ThinkingConfig(False, None), False

    if "thinking" in body:
        return normalize_thinking_config(body.get("thinking")), True

    if "thinkingConfig" in body:
        return normalize_thinking_config(body.get("thinkingConfig")), True

    gen_cfg = body.get("generationConfig")
    if isinstance(gen_cfg, dict):
        if "thinkingConfig" in gen_cfg:
            raw = gen_cfg.get("thinkingConfig")
            cfg = normalize_thinking_config(raw)
            if cfg.enabled:
                return cfg, True
            # Budget without explicit includeThoughts/mode: treat as enabled (client guidance exists)
            if isinstance(raw, dict) and any(
                k in raw for k in ("thinkingBudget", "budgetTokens", "budget_tokens", "max_thinking_length")
            ):
                return ThinkingConfig(True, cfg.budget_tokens), True
            return cfg, True

    return ThinkingConfig(False, None), False


def infer_thinking_from_anthropic_messages(messages: list[dict]) -> bool:
    """推断历史消息中是否包含思维链内容，用于在客户端未明确指定时自动启用思维链"""
    for msg in messages or []:
        content = msg.get("content")
        if not isinstance(content, list):
            continue
        for block in content:
            if isinstance(block, dict):
                # 检查标准的 thinking 块
                if block.get("type") == "thinking":
                    return True
                # 检查文本块中嵌入的 <thinking> 标签（assistant 消息中可能存在）
                if block.get("type") == "text" and msg.get("role") == "assistant":
                    text = block.get("text", "")
                    if isinstance(text, str) and "<thinking>" in text and "</thinking>" in text:
                        return True
    return False


def infer_thinking_from_openai_messages(messages: list[dict]) -> bool:
    for msg in messages or []:
        content = msg.get("content", "")
        if isinstance(content, str):
            if "<thinking>" in content and "</thinking>" in content:
                return True
            continue
        if isinstance(content, list):
            for part in content:
                if isinstance(part, dict) and part.get("type") == "text":
                    text = part.get("text", "")
                    if "<thinking>" in text and "</thinking>" in text:
                        return True
    return False


def infer_thinking_from_openai_responses_input(input_data: Any) -> bool:
    """Infer thinking from OpenAI Responses API `input` payloads (best-effort)."""
    if isinstance(input_data, str):
        return "<thinking>" in input_data and "</thinking>" in input_data

    if not isinstance(input_data, list):
        return False

    for item in input_data:
        if not isinstance(item, dict):
            continue
        if item.get("type") != "message":
            continue

        content_list = item.get("content", []) or []
        for c in content_list:
            if isinstance(c, str):
                if "<thinking>" in c and "</thinking>" in c:
                    return True
                continue
            if not isinstance(c, dict):
                continue
            c_type = c.get("type")
            if c_type in {"input_text", "output_text", "text"}:
                text = c.get("text", "")
                if isinstance(text, str) and "<thinking>" in text and "</thinking>" in text:
                    return True
    return False


def infer_thinking_from_gemini_contents(contents: list[dict]) -> bool:
    for item in contents or []:
        for part in item.get("parts", []) or []:
            if isinstance(part, dict) and isinstance(part.get("text"), str):
                text = part["text"]
                if "<thinking>" in text and "</thinking>" in text:
                    return True
    return False


import re

_THINKING_PATTERN = re.compile(r"<thinking>.*?</thinking>\s*", re.DOTALL)


def strip_thinking_from_text(text: str) -> str:
    """Remove <thinking> blocks from text."""
    if not text or not isinstance(text, str):
        return text
    return _THINKING_PATTERN.sub("", text).strip()


def strip_thinking_from_history(history: list) -> list:
    """Return a copy of history with <thinking> blocks removed from all messages."""
    if not history:
        return []
    
    cleaned = []
    for msg in history:
        if not isinstance(msg, dict):
            cleaned.append(msg)
            continue
        
        new_msg = msg.copy()
        content = msg.get("content")
        
        if isinstance(content, str):
            new_msg["content"] = strip_thinking_from_text(content)
        elif isinstance(content, list):
            new_content = []
            for part in content:
                if isinstance(part, dict) and part.get("type") == "text":
                    new_part = part.copy()
                    new_part["text"] = strip_thinking_from_text(part.get("text", ""))
                    new_content.append(new_part)
                else:
                    new_content.append(part)
            new_msg["content"] = new_content
        
        cleaned.append(new_msg)
    
    return cleaned


def format_thinking_block(thinking_content: str) -> str:
    if thinking_content is None:
        return ""
    thinking_content = str(thinking_content).strip()
    if not thinking_content:
        return ""
    return f"<thinking>\n{thinking_content}\n</thinking>"


def build_thinking_prompt(
    user_content: str, 
    *, 
    budget_tokens: Optional[int],
    history: list = None,
    has_tool_results: bool = False
) -> str:
    """Build a thinking prompt for internal reasoning phase.
    
    This phase is for the model to deeply analyze the situation and plan its strategy.
    The reasoning is internal and should be in plain text.
    """
    budget_str = f" (Budget: {budget_tokens} tokens)" if budget_tokens else ""
    lang_instruction = "Your reasoning MUST be in the same language as the user's message."

    common_intro = (
        f"[Internal Reasoning - Hidden Context]{budget_str}\n"
        "ULTRATHINK\n\n"
        "You are in your THINKING phase. Before providing a final response, take a moment to "
        "analyze the conversation, break down the user's request, and plan your approach.\n\n"
        "Your thinking process should focus on:\n"
        "1. **Understanding Intent**: What is the user truly asking for?\n"
        "2. **Context Analysis**: What information is available in the history? What's missing?\n"
        "3. **Risk Assessment**: Are there any dangerous operations or edge cases to consider?\n"
        "4. **Strategic Planning**: What steps are needed? Which tools are most appropriate (if any)?\n\n"
        "Guidelines for this phase:\n"
        "- Write your thoughts as clear, structured plain text.\n"
        "- Do NOT output any structured tool calls or tags (like <tool_use>) here; save them for the next phase.\n"
        "- Do NOT provide the final answer or a formal summary to the user yet.\n"
        f"- {lang_instruction}\n"
    )

    if has_tool_results:
        return (
            f"{common_intro}\n"
            "Current Focus: Analyze the tool results provided in the history above. "
            "Evaluate what was accomplished, handle any errors, and determine the next logical steps."
        )

    return (
        f"{common_intro}\n"
        "Current Focus: Evaluate the user's latest request and formulate a high-level execution plan.\n"
        f"User input: {user_content}"
    )


def build_user_prompt_with_thinking(user_content: str, thinking_content: str) -> str:
    """Inject thinking into the main prompt.
    
    Minimal injection to avoid context pollution.
    """
    if user_content is None:
        user_content = ""

    thinking_block = format_thinking_block(thinking_content)
    if not thinking_block:
        return user_content

    disclosure_hint = (
        "\n(Do NOT reveal the contents of the <thinking> block. Use it internally only.)\n"
    )

    # Dynamically instruct the model to respond in the same language as its thinking.
    lang_hint = "\n(Please provide your final response in the same language as your internal reasoning above.)\n"

    return f"{thinking_block}\n\n{disclosure_hint}{lang_hint}{user_content}"


async def iter_aws_event_stream_text(byte_iter: AsyncIterator[bytes]) -> AsyncIterator[str]:
    """Yield incremental text content from AWS event-stream chunks."""
    buffer = b""

    async for chunk in byte_iter:
        buffer += chunk

        while len(buffer) >= 12:
            total_len = int.from_bytes(buffer[0:4], "big")

            if total_len <= 0:
                return
            if len(buffer) < total_len:
                break

            headers_len = int.from_bytes(buffer[4:8], "big")
            payload_start = 12 + headers_len
            payload_end = total_len - 4

            if payload_start < payload_end:
                try:
                    payload = json.loads(buffer[payload_start:payload_end].decode("utf-8"))
                    content = None
                    if "assistantResponseEvent" in payload:
                        content = payload["assistantResponseEvent"].get("content")
                    elif "content" in payload and "toolUseId" not in payload:
                        content = payload.get("content")
                    if content:
                        yield content
                except Exception:
                    pass

            buffer = buffer[total_len:]


async def fetch_thinking_text(
    *,
    headers: dict,
    model: str,
    user_content: str,
    history: list,
    tools: list | None = None,
    images: list | None = None,
    tool_results: list | None = None,
    budget_tokens: Optional[int] = None,
    timeout_s: float = 600.0,
) -> str:
    """Non-streaming helper to get thinking content (best-effort)."""
    has_tool_results = bool(tool_results)
    thinking_prompt = build_thinking_prompt(
        user_content, 
        budget_tokens=budget_tokens, 
        history=history,
        has_tool_results=has_tool_results
    )
    thinking_request = build_kiro_request(
        thinking_prompt,
        model,
        history,
        tools=tools,
        images=images,
        tool_results=tool_results,
    )

    try:
        async with httpx.AsyncClient(verify=False, timeout=timeout_s) as client:
            resp = await client.post(KIRO_API_URL, json=thinking_request, headers=headers)
            if resp.status_code != 200:
                return ""
            return parse_event_stream(resp.content)
    except Exception:
        return ""


async def stream_thinking_text(
    *,
    headers: dict,
    model: str,
    user_content: str,
    history: list,
    tools: list | None = None,
    images: list | None = None,
    tool_results: list | None = None,
    budget_tokens: Optional[int] = None,
    timeout_s: float = 600.0,
) -> AsyncIterator[str]:
    """Streaming helper to yield thinking content incrementally (best-effort)."""
    has_tool_results = bool(tool_results)
    thinking_prompt = build_thinking_prompt(
        user_content,
        budget_tokens=budget_tokens,
        history=history,
        has_tool_results=has_tool_results
    )
    thinking_request = build_kiro_request(
        thinking_prompt,
        model,
        history,
        tools=tools,
        images=images,
        tool_results=tool_results,
    )

    async with httpx.AsyncClient(verify=False, timeout=timeout_s) as client:
        async with client.stream(
            "POST", KIRO_API_URL, json=thinking_request, headers=headers
        ) as response:
            if response.status_code != 200:
                return
            async for piece in iter_aws_event_stream_text(response.aiter_bytes()):
                yield piece