"""
AgentConnection for Claude Code SDK (claude_agent_sdk).

Uses your Claude Code subscription — no direct API costs.
Truly streams via a queue bridge between the async SDK generator
and the synchronous Iterator[StreamEvent] interface.
"""

import logging
import queue
from typing import Iterator

from cht.agent.base import (
    AgentConnection,
    AssistantMessage,
    ImageBlock,
    Message,
    StreamEvent,
    TextBlock,
    TextDelta,
    Tool,
    ToolCallEnd,
    ToolCallStart,
    ToolResult,
    ToolUse,
    TranscriptBlock,
    UserMessage,
    Done,
    Error,
)

log = logging.getLogger(__name__)

MODELS = [
    "claude-sonnet-4-6",
    "claude-opus-4-6",
    "claude-haiku-4-5",
]

_SENTINEL = object()


def _messages_to_prompt(messages: list[Message]) -> str:
    """Flatten structured messages into a text prompt for the SDK."""
    lines = []
    for msg in messages:
        if isinstance(msg, UserMessage):
            parts = []
            for b in msg.content:
                if isinstance(b, TextBlock):
                    parts.append(b.text)
                elif isinstance(b, ImageBlock):
                    m, s = divmod(int(b.timestamp), 60)
                    parts.append(f"[Frame {b.frame_id} at {m:02d}:{s:02d} — {b.path}]")
                elif isinstance(b, TranscriptBlock):
                    m1, s1 = divmod(int(b.start), 60)
                    m2, s2 = divmod(int(b.end), 60)
                    parts.append(f"[Transcript {b.transcript_id} {m1:02d}:{s1:02d}-{m2:02d}:{s2:02d}: {b.text}]")
            lines.append(f"User: {' '.join(parts)}")
        elif isinstance(msg, AssistantMessage):
            text = " ".join(b.text for b in msg.content if isinstance(b, TextBlock))
            lines.append(f"Assistant: {text}")
        elif isinstance(msg, ToolUse):
            lines.append(f"[Tool call: {msg.tool_name}({msg.input})]")
        elif isinstance(msg, ToolResult):
            out = msg.output or msg.error or ""
            lines.append(f"[Tool result: {out}]")
    return "\n".join(lines)


class ClaudeSDKConnection:
    """AgentConnection using claude_agent_sdk — requires Claude Code CLI."""

    def __init__(self, cwd: str | None = None, max_turns: int | None = None,
                 model: str = MODELS[0], permission_mode: str | None = None):
        from cht.config import AGENT_PERMISSION_MODE, AGENT_MAX_TURNS
        self._cwd = cwd
        self._max_turns = max_turns or AGENT_MAX_TURNS
        self._model = model
        self._permission_mode = permission_mode or AGENT_PERMISSION_MODE
        self._cancelled = False

    @property
    def name(self) -> str:
        return f"claude-sdk/{self._model}"

    def available_models(self) -> list[str]:
        return list(MODELS)

    def get_model(self) -> str:
        return self._model

    def set_model(self, model: str) -> None:
        self._model = model

    def prompt(
        self,
        messages: list[Message],
        tools: list[Tool],
    ) -> Iterator[StreamEvent]:
        from claude_agent_sdk import (
            query,
            ClaudeAgentOptions,
            AssistantMessage as SDKAssistantMessage,
            TextBlock as SDKTextBlock,
            ResultMessage,
            CLINotFoundError,
            CLIConnectionError,
        )

        prompt_text = _messages_to_prompt(messages)
        self._cancelled = False
        q: queue.Queue = queue.Queue()

        # Determine cwd from the last UserMessage's image paths if available
        cwd = self._cwd
        if not cwd:
            for msg in reversed(messages):
                if isinstance(msg, UserMessage):
                    for b in msg.content:
                        if isinstance(b, ImageBlock):
                            cwd = str(b.path.parent.parent)  # session_dir
                            break
                    if cwd:
                        break

        async def _run():
            try:
                got_assistant_text = False
                async for msg in query(
                    prompt=prompt_text,
                    options=ClaudeAgentOptions(
                        model=self._model,
                        cwd=cwd or ".",
                        max_turns=self._max_turns,
                        permission_mode=self._permission_mode,
                    ),
                ):
                    if self._cancelled:
                        break
                    if isinstance(msg, SDKAssistantMessage):
                        for block in msg.content:
                            if isinstance(block, SDKTextBlock):
                                q.put(TextDelta(text=block.text))
                                got_assistant_text = True
                    elif isinstance(msg, ResultMessage):
                        # Only use ResultMessage.result if we got no text from AssistantMessages
                        if msg.result and not got_assistant_text:
                            q.put(TextDelta(text=msg.result))
                q.put(Done(stop_reason="end_turn"))
            except CLINotFoundError:
                q.put(Error(
                    message="Claude Code CLI not found.\n"
                    "Install it: https://claude.ai/code\n"
                    "Then run `claude` once in a terminal to authenticate."
                ))
            except CLIConnectionError as e:
                if "auth" in str(e).lower() or "login" in str(e).lower() or "401" in str(e):
                    q.put(Error(
                        message="Claude Code not authenticated.\n"
                        "Run `claude` in a terminal and complete the login flow, then retry."
                    ))
                else:
                    q.put(Error(message=str(e)))
            except Exception as e:
                q.put(Error(message=str(e)))
            finally:
                q.put(_SENTINEL)

        import asyncio
        import threading

        def _thread():
            loop = asyncio.new_event_loop()
            try:
                loop.run_until_complete(_run())
            finally:
                loop.close()

        t = threading.Thread(target=_thread, daemon=True, name="claude_sdk_stream")
        t.start()

        while True:
            item = q.get()
            if item is _SENTINEL:
                break
            yield item

    def cancel(self) -> None:
        self._cancelled = True