"""
Chat command for kt-cli.

Provides interactive chat interface with running model server.
"""

import json
import os
import sys
from datetime import datetime
from pathlib import Path
from typing import Optional

import typer
from rich.console import Console
from rich.markdown import Markdown
from rich.panel import Panel
from rich.prompt import Prompt, Confirm

from kt_kernel.cli.config.settings import get_settings
from kt_kernel.cli.i18n import t
from kt_kernel.cli.utils.console import (
    console,
    print_error,
    print_info,
    print_success,
    print_warning,
)

# Try to import OpenAI SDK
try:
    from openai import OpenAI

    HAS_OPENAI = True
except ImportError:
    HAS_OPENAI = False


def chat(
    host: Optional[str] = typer.Option(
        None,
        "--host",
        "-H",
        help="Server host address",
    ),
    port: Optional[int] = typer.Option(
        None,
        "--port",
        "-p",
        help="Server port",
    ),
    model: Optional[str] = typer.Option(
        None,
        "--model",
        "-m",
        help="Model name (if server hosts multiple models)",
    ),
    temperature: float = typer.Option(
        0.7,
        "--temperature",
        "-t",
        help="Sampling temperature (0.0 to 2.0)",
    ),
    max_tokens: int = typer.Option(
        2048,
        "--max-tokens",
        help="Maximum tokens to generate",
    ),
    system_prompt: Optional[str] = typer.Option(
        None,
        "--system",
        "-s",
        help="System prompt",
    ),
    save_history: bool = typer.Option(
        True,
        "--save-history/--no-save-history",
        help="Save conversation history",
    ),
    history_file: Optional[Path] = typer.Option(
        None,
        "--history-file",
        help="Path to save conversation history",
    ),
    stream: bool = typer.Option(
        True,
        "--stream/--no-stream",
        help="Enable streaming output",
    ),
) -> None:
    """Start interactive chat with a running model server.

    Examples:
        kt chat                          # Connect to default server
        kt chat --host 127.0.0.1 -p 8080 # Connect to specific server
        kt chat -t 0.9 --max-tokens 4096 # Adjust generation parameters
    """
    if not HAS_OPENAI:
        print_error(t("chat_openai_required"))
        console.print()
        console.print(t("chat_install_hint"))
        console.print("  pip install openai")
        raise typer.Exit(1)

    settings = get_settings()

    # Resolve server connection
    final_host = host or settings.get("server.host", "127.0.0.1")
    final_port = port or settings.get("server.port", 30000)

    # Construct base URL for OpenAI-compatible API
    base_url = f"http://{final_host}:{final_port}/v1"

    console.print()
    console.print(
        Panel.fit(
            f"[bold cyan]{t('chat_title')}[/bold cyan]\n\n"
            f"{t('chat_server')}: [yellow]{final_host}:{final_port}[/yellow]\n"
            f"{t('chat_temperature')}: [cyan]{temperature}[/cyan] | {t('chat_max_tokens')}: [cyan]{max_tokens}[/cyan]\n\n"
            f"[dim]{t('chat_help_hint')}[/dim]",
            border_style="cyan",
        )
    )
    console.print()

    # Check for proxy environment variables
    proxy_vars = ["HTTP_PROXY", "HTTPS_PROXY", "http_proxy", "https_proxy", "ALL_PROXY", "all_proxy"]
    detected_proxies = {var: os.environ.get(var) for var in proxy_vars if os.environ.get(var)}

    if detected_proxies:
        proxy_info = ", ".join(f"{k}={v}" for k, v in detected_proxies.items())
        console.print()
        print_warning(t("chat_proxy_detected"))
        console.print(f"  [dim]{proxy_info}[/dim]")
        console.print()

        use_proxy = Confirm.ask(t("chat_proxy_confirm"), default=False)

        if not use_proxy:
            # Temporarily disable proxy for this connection
            for var in proxy_vars:
                if var in os.environ:
                    del os.environ[var]
            print_info(t("chat_proxy_disabled"))
            console.print()

    # Initialize OpenAI client
    try:
        client = OpenAI(
            base_url=base_url,
            api_key="EMPTY",  # SGLang doesn't require API key
        )

        # Test connection
        print_info(t("chat_connecting"))
        models = client.models.list()
        available_models = [m.id for m in models.data]

        if not available_models:
            print_error(t("chat_no_models"))
            raise typer.Exit(1)

        # Select model
        if model:
            if model not in available_models:
                print_warning(t("chat_model_not_found", model=model, available=", ".join(available_models)))
                selected_model = available_models[0]
            else:
                selected_model = model
        else:
            selected_model = available_models[0]

        print_success(t("chat_connected", model=selected_model))
        console.print()

        # Load tokenizer for accurate token counting
        tokenizer = None
        try:
            from transformers import AutoTokenizer

            # selected_model is the model path
            tokenizer = AutoTokenizer.from_pretrained(selected_model, trust_remote_code=True)
            console.print(f"[dim]Loaded tokenizer from {selected_model}[/dim]")
            console.print()
        except Exception as e:
            console.print(f"[dim yellow]Warning: Could not load tokenizer, token counts will be estimated[/dim]")
            console.print()

    except Exception as e:
        print_error(t("chat_connect_failed", error=str(e)))
        console.print()
        console.print(t("chat_server_not_running"))
        console.print("  kt run <model>")
        raise typer.Exit(1)

    # Initialize conversation history
    messages = []

    # Add system prompt if provided
    if system_prompt:
        messages.append({"role": "system", "content": system_prompt})

    # Setup history file
    if save_history:
        if history_file is None:
            history_dir = settings.config_dir / "chat_history"
            history_dir.mkdir(parents=True, exist_ok=True)
            timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
            history_file = history_dir / f"chat_{timestamp}.json"
        else:
            history_file = Path(history_file)
            history_file.parent.mkdir(parents=True, exist_ok=True)

    # Main chat loop
    try:
        while True:
            # Get user input - use console.input() for better CJK character support
            try:
                user_input = console.input(f"[bold green]{t('chat_user_prompt')}[/bold green]: ")
            except (EOFError, KeyboardInterrupt):
                console.print()
                print_info(t("chat_goodbye"))
                break

            if not user_input.strip():
                continue

            # Handle special commands
            if user_input.startswith("/"):
                if _handle_command(user_input, messages, temperature, max_tokens):
                    continue
                else:
                    break  # Exit command

            # Add user message to history
            messages.append({"role": "user", "content": user_input})

            # Generate response
            console.print()
            console.print(f"[bold cyan]{t('chat_assistant_prompt')}[/bold cyan]")

            try:
                if stream:
                    # Streaming response
                    response_content = _stream_response(
                        client, selected_model, messages, temperature, max_tokens, tokenizer
                    )
                else:
                    # Non-streaming response
                    response_content = _generate_response(
                        client, selected_model, messages, temperature, max_tokens, tokenizer
                    )

                # Add assistant response to history
                messages.append({"role": "assistant", "content": response_content})

                console.print()

            except Exception as e:
                print_error(t("chat_generation_error", error=str(e)))
                # Remove the user message that caused the error
                messages.pop()
                continue

            # Save history if enabled
            if save_history:
                _save_history(history_file, messages, selected_model)

    except KeyboardInterrupt:
        console.print()
        console.print()
        print_info(t("chat_interrupted"))

    # Final history save
    if save_history and messages:
        _save_history(history_file, messages, selected_model)
        console.print(f"[dim]{t('chat_history_saved', path=str(history_file))}[/dim]")
        console.print()


def _stream_response(
    client: "OpenAI",
    model: str,
    messages: list,
    temperature: float,
    max_tokens: int,
    tokenizer=None,
) -> str:
    """Generate streaming response and display in real-time."""
    import time

    response_content = ""
    reasoning_content = ""

    # Performance tracking
    first_token_time = None
    chunk_count = 0

    try:
        # Start timing before sending request
        start_time = time.time()

        stream = client.chat.completions.create(
            model=model,
            messages=messages,
            temperature=temperature,
            max_tokens=max_tokens,
            stream=True,
        )

        for chunk in stream:
            delta = chunk.choices[0].delta if chunk.choices else None
            if delta:
                reasoning_delta = getattr(delta, "reasoning_content", None)
                if reasoning_delta:
                    if first_token_time is None:
                        first_token_time = time.time()
                    reasoning_content += reasoning_delta
                    console.print(reasoning_delta, end="", style="dim")
                    chunk_count += 1

                if delta.content:
                    if first_token_time is None:
                        first_token_time = time.time()
                    content = delta.content
                    response_content += content
                    console.print(content, end="")
                    chunk_count += 1

        console.print()  # Newline after streaming

        # Display performance metrics
        end_time = time.time()
        if first_token_time and chunk_count > 0:
            ttft = first_token_time - start_time
            total_time = end_time - start_time

            # Calculate TPOT based on chunks
            if chunk_count > 1:
                generation_time = total_time - ttft
                tpot = generation_time / (chunk_count - 1)
            else:
                tpot = 0

            # Calculate accurate token counts using tokenizer
            if tokenizer:
                input_tokens = _count_tokens_with_tokenizer(messages, tokenizer)
                output_tokens = _count_tokens_with_tokenizer(
                    [{"role": "assistant", "content": response_content}], tokenizer
                )
                token_prefix = ""
            else:
                # Fallback to estimation
                input_tokens = _estimate_tokens(messages)
                output_tokens = _estimate_tokens([{"role": "assistant", "content": response_content}])
                token_prefix = "~"

            # Build metrics display
            metrics = f"[dim]Total: {total_time*1000:.0f}ms | TTFT: {ttft*1000:.0f}ms"
            if tpot > 0:
                metrics += f" | TPOT: {tpot*1000:.1f}ms"
            metrics += f" | In: {token_prefix}{input_tokens} | Out: {token_prefix}{output_tokens}"
            metrics += "[/dim]"

            console.print(metrics)

    except Exception as e:
        raise Exception(f"Streaming error: {e}")

    return response_content


def _count_tokens_with_tokenizer(messages: list, tokenizer) -> int:
    """Count tokens accurately using the model's tokenizer."""
    try:
        # Concatenate all message content
        text = ""
        for msg in messages:
            role = msg.get("role", "")
            content = msg.get("content", "")
            # Simple format: role + content
            text += f"{role}: {content}\n"

        # Encode and count tokens - suppress any debug output from custom tokenizers
        import os
        import sys
        from contextlib import redirect_stdout, redirect_stderr

        with open(os.devnull, "w") as devnull:
            with redirect_stdout(devnull), redirect_stderr(devnull):
                tokens = tokenizer.encode(text, add_special_tokens=True)
        return len(tokens)
    except Exception:
        # Fallback to estimation if tokenizer fails
        return _estimate_tokens(messages)


def _estimate_tokens(messages: list) -> int:
    """Estimate token count for messages (rough approximation)."""
    total_chars = 0
    for msg in messages:
        content = msg.get("content", "")
        total_chars += len(content)

    # Rough estimation:
    # - English: ~4 chars per token
    # - Chinese: ~1.5 chars per token
    # Use 2.5 as average
    return max(1, int(total_chars / 2.5))


def _generate_response(
    client: "OpenAI",
    model: str,
    messages: list,
    temperature: float,
    max_tokens: int,
    tokenizer=None,
) -> str:
    """Generate non-streaming response."""
    import time

    try:
        start_time = time.time()

        response = client.chat.completions.create(
            model=model,
            messages=messages,
            temperature=temperature,
            max_tokens=max_tokens,
            stream=False,
        )

        end_time = time.time()
        total_time = end_time - start_time

        content = response.choices[0].message.content

        # Display as markdown
        md = Markdown(content)
        console.print(md)

        # Calculate accurate token counts using tokenizer
        if tokenizer:
            input_tokens = _count_tokens_with_tokenizer(messages, tokenizer)
            output_tokens = _count_tokens_with_tokenizer([{"role": "assistant", "content": content}], tokenizer)
            token_prefix = ""
        else:
            # Fallback to API usage or estimation
            input_tokens = response.usage.prompt_tokens if response.usage else _estimate_tokens(messages)
            output_tokens = (
                response.usage.completion_tokens
                if response.usage
                else _estimate_tokens([{"role": "assistant", "content": content}])
            )
            token_prefix = "" if response.usage else "~"

        # Display performance metrics
        console.print(
            f"[dim]Time: {total_time*1000:.0f}ms | "
            f"In: {token_prefix}{input_tokens} | Out: {token_prefix}{output_tokens}[/dim]"
        )

        return content

    except Exception as e:
        raise Exception(f"Generation error: {e}")


def _handle_command(command: str, messages: list, temperature: float, max_tokens: int) -> bool:
    """Handle special commands. Returns True to continue chat, False to exit."""
    cmd = command.lower().strip()

    if cmd in ["/quit", "/exit", "/q"]:
        console.print()
        print_info(t("chat_goodbye"))
        return False

    elif cmd in ["/help", "/h"]:
        console.print()
        console.print(
            Panel(
                f"[bold]{t('chat_help_title')}[/bold]\n\n{t('chat_help_content')}",
                title="Help",
                border_style="cyan",
            )
        )
        console.print()
        return True

    elif cmd in ["/clear", "/c"]:
        messages.clear()
        console.print()
        print_success(t("chat_history_cleared"))
        console.print()
        return True

    elif cmd in ["/history", "/hist"]:
        console.print()
        if not messages:
            print_info(t("chat_no_history"))
        else:
            console.print(
                Panel(
                    _format_history(messages),
                    title=t("chat_history_title", count=len(messages)),
                    border_style="cyan",
                )
            )
        console.print()
        return True

    elif cmd in ["/info", "/i"]:
        console.print()
        console.print(
            Panel(
                f"[bold]{t('chat_info_title')}[/bold]\n\n{t('chat_info_content', temperature=temperature, max_tokens=max_tokens, messages=len(messages))}",
                title="Info",
                border_style="cyan",
            )
        )
        console.print()
        return True

    elif cmd in ["/retry", "/r"]:
        if len(messages) >= 2 and messages[-1]["role"] == "assistant":
            # Remove last assistant response
            messages.pop()
            print_info(t("chat_retrying"))
            console.print()
        else:
            print_warning(t("chat_no_retry"))
            console.print()
        return True

    else:
        print_warning(t("chat_unknown_command", command=command))
        console.print(f"[dim]{t('chat_unknown_hint')}[/dim]")
        console.print()
        return True


def _format_history(messages: list) -> str:
    """Format conversation history for display."""
    lines = []
    for i, msg in enumerate(messages, 1):
        role = msg["role"].capitalize()
        content = msg["content"]

        # Truncate long messages
        if len(content) > 200:
            content = content[:200] + "..."

        lines.append(f"[bold]{i}. {role}:[/bold] {content}")

    return "\n\n".join(lines)


def _save_history(file_path: Path, messages: list, model: str) -> None:
    """Save conversation history to file."""
    try:
        history_data = {
            "model": model,
            "timestamp": datetime.now().isoformat(),
            "messages": messages,
        }

        with open(file_path, "w", encoding="utf-8") as f:
            json.dump(history_data, f, indent=2, ensure_ascii=False)

    except Exception as e:
        print_warning(f"Failed to save history: {e}")