import gradio as gr
import openai
import PyPDF2
import os
from datetime import datetime

# ✅ openai 0.28：API 金鑰設定
openai.api_key = os.getenv("OPENAI_API_KEY")

topics = ["教育哲學", "教育社會學", "教育心理學", "課程與教學", "教學原理", "班級經營", "教育測驗與評量", "青少年問題與輔導"]
difficulties = ["簡單", "中等", "困難"]

user_errors = {}
error_history = {}

DEFAULT_PDF_PATH = "教材.pdf"

def extract_text_from_pdf():
    if not os.path.exists(DEFAULT_PDF_PATH):
        print(f"[錯誤] 教材未找到：{DEFAULT_PDF_PATH}")
        return ""
    try:
        with open(DEFAULT_PDF_PATH, "rb") as f:
            reader = PyPDF2.PdfReader(f)
            return "\n".join([page.extract_text() or "" for page in reader.pages])
    except Exception as e:
        print(f"[錯誤] PDF 載入失敗：{e}")
        return ""

pdf_text = extract_text_from_pdf()

def generate_question(topic, difficulty):
    if not pdf_text.strip():
        return "⚠️ 無法載入教材內容，請確認 PDF 是否存在。"
    prompt = f"請根據以下教育學教材內容，設計一個屬於「{topic}」主題、「{difficulty}」難度的考題：\n\n{pdf_text}"
    try:
        response = openai.ChatCompletion.create(
            model="gpt-4o-mini-2024-07-18",
            messages=[
                {"role": "system", "content": "你是一位教育專家，請根據教材內容設計問題。"},
                {"role": "user", "content": prompt}
            ]
        )
        return response["choices"][0]["message"]["content"]
    except Exception as e:
        return f"⚠️ 發生錯誤：{e}"

def analyze_answer(user_input, topic):
    global user_errors, error_history
    if not user_input.strip():
        return "⚠️ 請輸入回答。"
    if not pdf_text.strip():
        return "⚠️ 教材內容未載入，請確認 PDF。"
    
    current_date = datetime.today().strftime("%Y-%m-%d")
    prompt = f"請根據以下教材內容，檢查學生的回答是否正確，並提供正確答案與講解：\n{pdf_text}\n\n學生回答：'{user_input}'"

    try:
        response = openai.ChatCompletion.create(
            model="gpt-4o-mini-2024-07-18",
            messages=[
                {"role": "system", "content": "你是一位教育專家，請根據教材內容分析學生回答。"},
                {"role": "user", "content": prompt}
            ]
        )
        feedback = response["choices"][0]["message"]["content"]
    except Exception as e:
        return f"⚠️ 發生錯誤：{e}"

    if "❌" in feedback or "錯" in feedback:
        user_errors[topic] = user_errors.get(topic, 0) + 1
        error_history.setdefault(current_date, []).append({
            "題目": topic,
            "回答": user_input,
            "AI 分析": feedback
        })
    return feedback

def get_errors_by_date_safe(date_str):
    try:
        datetime.strptime(date_str, "%Y-%m-%d")
    except ValueError:
        return "⚠️ 日期格式錯誤，請使用 YYYY-MM-DD。"
    errors = error_history.get(date_str)
    if not errors:
        return "✅ 該日無錯題紀錄。"
    return "\n\n".join([f"🔹 題目: {e['題目']}\n📝 回答: {e['回答']}\n📖 AI 分析: {e['AI 分析']}" for e in errors])

with gr.Blocks() as demo:
    gr.Markdown("# 👨‍🏫 教師檢定智慧陪讀家教 🚀")

    with gr.Row():
        topic_input = gr.Dropdown(choices=topics, label="選擇複習主題")
        difficulty_input = gr.Dropdown(choices=difficulties, label="選擇難度等級")
    ask_btn = gr.Button("🎯 生成問題")
    question_output = gr.Textbox(label="AI 生成的問題", lines=4)
    ask_btn.click(fn=lambda t, d: generate_question(t, d),
                  inputs=[topic_input, difficulty_input],
                  outputs=question_output)

    user_answer = gr.Textbox(label="你的回答", lines=3)
    analyze_btn = gr.Button("📊 分析回答")
    analysis_result = gr.Textbox(label="AI 分析與講解", lines=5)
    analyze_btn.click(fn=lambda ans, topic: analyze_answer(ans, topic),
                      inputs=[user_answer, topic_input],
                      outputs=analysis_result)

    gr.Markdown("---")
    gr.Markdown("📅 查詢錯題紀錄")
    date_input = gr.Textbox(label="輸入日期（YYYY-MM-DD）")
    search_errors_btn = gr.Button("🔍 查看該日期錯題")
    error_history_output = gr.Textbox(label="錯題紀錄", lines=5)
    search_errors_btn.click(fn=get_errors_by_date_safe,
                            inputs=date_input,
                            outputs=error_history_output)

demo.launch()