from fastapi import APIRouter, status, Depends, BackgroundTasks, HTTPException
from fastapi.responses import JSONResponse
from src.utils.logger import logger
from pydantic import BaseModel, Field
from typing import List, Dict, Any, Optional
from src.agents.lesson_practice.flow import lesson_practice_agent
from src.apis.models.lesson_models import Lesson, LessonResponse, LessonDetailResponse
import json
import os
import uuid
from datetime import datetime

router = APIRouter(prefix="/lesson", tags=["AI"])


class LessonPracticeRequest(BaseModel):
    unit: str = Field(..., description="Unit of the lesson")
    vocabulary: list = Field(..., description="Vocabulary for the lesson")
    key_structures: list = Field(..., description="Key structures for the lesson")
    practice_questions: list = Field(
        ..., description="Practice questions for the lesson"
    )
    student_level: str = Field("beginner", description="Student's level of English")
    query: str = Field(..., description="User query for the lesson")
    session_id: str = Field(..., description="Session ID for the lesson")


# Helper function to load lessons from JSON file
def load_lessons_from_file() -> List[Lesson]:
    """Load lessons from the JSON file"""
    try:
        lessons_file_path = os.path.join(os.path.dirname(__file__), "..", "..", "data", "lessons.json")
        
        if not os.path.exists(lessons_file_path):
            logger.warning(f"Lessons file not found at {lessons_file_path}")
            return []
            
        with open(lessons_file_path, 'r', encoding='utf-8') as file:
            lessons_data = json.load(file)
            
        # Convert to Lesson objects
        lessons = []
        for lesson_data in lessons_data:
            try:
                lesson = Lesson(**lesson_data)
                lessons.append(lesson)
            except Exception as e:
                logger.error(f"Error parsing lesson {lesson_data.get('id', 'unknown')}: {str(e)}")
                continue
                
        return lessons
    except Exception as e:
        logger.error(f"Error loading lessons: {str(e)}")
        return []


@router.get("/all", response_model=LessonResponse)
async def get_all_lessons():
    """
    Get all available lessons
    
    Returns:
        LessonResponse: Contains list of all lessons and total count
    """
    try:
        lessons = load_lessons_from_file()
        
        return LessonResponse(
            lessons=lessons,
            total=len(lessons)
        )
    except Exception as e:
        logger.error(f"Error retrieving lessons: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to retrieve lessons"
        )


@router.get("/{lesson_id}", response_model=LessonDetailResponse)
async def get_lesson_by_id(lesson_id: str):
    """
    Get a specific lesson by ID
    
    Args:
        lesson_id (str): The unique identifier of the lesson
        
    Returns:
        LessonDetailResponse: Contains the lesson details
    """
    try:
        lessons = load_lessons_from_file()
        
        # Find the lesson with the specified ID
        lesson = next((l for l in lessons if l.id == lesson_id), None)
        
        if not lesson:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Lesson with ID '{lesson_id}' not found"
            )
            
        return LessonDetailResponse(lesson=lesson)
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Error retrieving lesson {lesson_id}: {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to retrieve lesson"
        )


@router.get("/search/unit/{unit_name}")
async def search_lessons_by_unit(unit_name: str):
    """
    Search lessons by unit name (case-insensitive partial match)
    
    Args:
        unit_name (str): Part of the unit name to search for
        
    Returns:
        LessonResponse: Contains list of matching lessons
    """
    try:
        lessons = load_lessons_from_file()
        
        # Filter lessons by unit name (case-insensitive partial match)
        matching_lessons = [
            lesson for lesson in lessons 
            if unit_name.lower() in lesson.unit.lower()
        ]
        
        return LessonResponse(
            lessons=matching_lessons,
            total=len(matching_lessons)
        )
    except Exception as e:
        logger.error(f"Error searching lessons by unit '{unit_name}': {str(e)}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to search lessons"
        )


@router.post("/chat")
async def chat(request: LessonPracticeRequest):
    response = await lesson_practice_agent().ainvoke(
        {
            "unit": request.unit,
            "vocabulary": request.vocabulary,
            "key_structures": request.key_structures,
            "practice_questions": request.practice_questions,
            "student_level": request.student_level,
            "messages": [request.query],
        },
        {"configurable": {"thread_id": request.session_id}},
    )
    return JSONResponse(
        content=response["messages"][-1].content, status_code=status.HTTP_200_OK
    )