import os
import openai


def plan_course(messages, sources):
    """
    Generate a structured course outline as a JSON object using the conversation and collected sources.

    This function reads a JSON schema from the repository (``course_outline_schema.json``) and instructs
    the language model to produce an output that strictly follows the schema. The conversation history
    (``messages``) and list of resources (``sources``) are provided to the model as context.

    Args:
        messages (list[dict]): Conversation history with roles and content.
        sources (list[dict]): List of source dictionaries with "title" and "url" keys.

    Returns:
        str: A JSON string representing the course outline that matches the schema.

    Raises:
        RuntimeError: If the OpenAI API call fails.
        ValueError: If an API key is not provided via environment variables.
    """
    # Ensure API key is available (support COURSECREATOR_API_KEY as fallback)
    api_key = os.getenv("OPENAI_API_KEY") or os.getenv("COURSECREATOR_API_KEY")
    if not api_key:
        raise ValueError(
            "An OpenAI API key is required to plan the course (set OPENAI_API_KEY or COURSECREATOR_API_KEY)"
        )
    # Load the JSON schema from the local file to guide the model
    schema_path = os.path.join(os.path.dirname(__file__) or ".", "course_outline_schema.json")
    try:
        with open(schema_path, "r") as f:
            schema_content = f.read().strip()
    except Exception:
        # If the schema is not found, define a minimal fallback structure
        schema_content = (
            '{"title":"","description":"","course_plan":[]}'
        )
    # Compose system prompt: instruct the model to output JSON matching the schema and to use
    # information from the conversation and the provided sources.
    system_prompt = (
        "You are an expert course planner. Use the conversation and sources provided to produce a "
        "detailed course outline. Your response MUST be a valid JSON object that strictly follows "
        "this schema:\n\n"
        f"{schema_content}\n\n"
        "Do not wrap your answer in markdown or include any additional commentary. Only output the JSON."
    )
    # Build messages array for the model: include system prompt, conversation, and a description of sources
    formatted_messages = [
        {"role": "system", "content": system_prompt},
    ]
    # Include the conversation history
    for msg in messages:
        formatted_messages.append(msg)
    # Append sources description if present
    if sources:
        # Format sources as a numbered list for the model to reference
        source_lines = []
        for i, src in enumerate(sources, start=1):
            if isinstance(src, dict):
                t = src.get("title", "")
                u = src.get("url", "")
                source_lines.append(f"[{i}] {t} - {u}")
        source_text = "\n".join(source_lines)
        formatted_messages.append({"role": "system", "content": f"Sources:\n{source_text}"})
    # Model configuration
    model = os.getenv("OPENAI_MODEL", "gpt-3.5-turbo")
    temperature = float(os.getenv("TEMPERATURE", "0.3"))  # Lower temperature for more deterministic JSON
    max_tokens = int(os.getenv("MAX_OUTPUT_TOKENS", "4096"))
    try:
        # Use new OpenAI client if available
        if hasattr(openai, "OpenAI"):
            client = openai.OpenAI(api_key=api_key)
            try:
                resp = client.chat.completions.create(
                    model=model,
                    messages=formatted_messages,
                    temperature=temperature,
                    max_tokens=max_tokens,
                )
            except Exception:
                # Fallback to max_completion_tokens if model requires it
                resp = client.chat.completions.create(
                    model=model,
                    messages=formatted_messages,
                    temperature=temperature,
                    max_completion_tokens=max_tokens,
                )
            content = resp.choices[0].message.content
        else:
            # Legacy OpenAI SDK (<1.0)
            openai.api_key = api_key
            try:
                resp = openai.ChatCompletion.create(
                    model=model,
                    messages=formatted_messages,
                    temperature=temperature,
                    max_tokens=max_tokens,
                )
            except Exception:
                resp = openai.ChatCompletion.create(
                    model=model,
                    messages=formatted_messages,
                    temperature=temperature,
                    max_completion_tokens=max_tokens,
                )
            content = resp["choices"][0]["message"]["content"]
    except Exception as e:
        raise RuntimeError(f"OpenAI API error: {e}")
    # The content should be valid JSON. Return as string so the caller can write to file or parse.
    return content