import requests
import gradio as gr
from datetime import datetime, timedelta

# USGS API 的基礎 URL
USGS_API_BASE_URL = "https://earthquake.usgs.gov/fdsnws/event/1/query"

def format_earthquake_info_markdown(data):
    """
    將從 API 獲取的地震資料格式化為 Markdown 字串。
    """
    if not data or 'features' not in data or not data['features']:
        return "在指定的條件下，找不到任何地震資料。"

    count = data['metadata']['count']
    title = data['metadata']['title']
    
    # 建立 Markdown 表格的標頭
    md_output = f"## {title}\n\n"
    md_output += f"**查詢成功，共找到 {count} 筆地震資料。**\n\n"
    md_output += "| 時間 (UTC) | 地點 | 芮氏規模 | 深度 (公里) | 經緯度 |\n"
    md_output += "|---|---|---|---|---|\n"

    # 填入每一筆地震資料
    for feature in data['features']:
        properties = feature['properties']
        geometry = feature['geometry']
        
        event_time_utc = datetime.fromtimestamp(properties['time'] / 1000)
        time_str = event_time_utc.strftime('%Y-%m-%d %H:%M:%S')
        
        magnitude = properties['mag']
        place = properties['place'].replace('|', '\|') # 避免 Markdown 表格語法衝突
        longitude, latitude, depth = geometry['coordinates']
        
        md_output += f"| {time_str} | {place} | {magnitude:.2f} | {depth:.2f} | ({latitude:.4f}, {longitude:.4f}) |\n"
        
    return md_output

def query_earthquakes(
    starttime_str: str,
    endtime_str: str,
    min_magnitude: float,
    use_geo: bool,
    min_lat: float, max_lat: float,
    min_lon: float, max_lon: float
):
    """
    接收來自 Gradio UI 的輸入，查詢並回傳格式化的地震資料。
    """
    params = {
        "format": "geojson",
        "starttime": starttime_str,
        "endtime": endtime_str,
        "minmagnitude": min_magnitude,
        "limit": 500,  # 限制回傳數量，避免 UI 過於壅塞
        "orderby": "time"
    }

    # 如果使用者勾選了 "指定地理範圍"
    if use_geo:
        # 簡單的驗證
        if not all([min_lat, max_lat, min_lon, max_lon]):
            return "錯誤：若要指定地理範圍，則經緯度四個欄位皆須填寫。"
        if min_lat >= max_lat or min_lon >= max_lon:
            return "錯誤：最小經緯度必須小於最大經緯度。"
            
        params.update({
            "minlatitude": min_lat,
            "maxlatitude": max_lat,
            "minlongitude": min_lon,
            "maxlongitude": max_lon
        })

    try:
        response = requests.get(USGS_API_BASE_URL, params=params, timeout=20)
        response.raise_for_status()
        data = response.json()
        return format_earthquake_info_markdown(data)
    except requests.exceptions.RequestException as e:
        return f"錯誤：網路請求失敗: {e}"
    except Exception as e:
        return f"發生未知錯誤: {e}"

# --- Gradio 介面設計 ---
with gr.Blocks(theme=gr.themes.Soft()) as demo:
    gr.Markdown("# 🌎 USGS 地震資料查詢工具")
    gr.Markdown("透過此工具，您可以查詢美國地質調查局 (USGS) 的全球地震紀錄。")
    
    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### 1. 設定查詢條件")
            # 預設查詢時間為過去 7 天
            today = datetime.now()
            seven_days_ago = today - timedelta(days=7)
            
            starttime_input = gr.Textbox(label="查詢開始日期", value=seven_days_ago.strftime('%Y-%m-%d'))
            endtime_input = gr.Textbox(label="查詢結束日期", value=today.strftime('%Y-%m-%d'))
            
            magnitude_slider = gr.Slider(
                minimum=0, maximum=10, step=0.1,
                label="最小芮氏規模",
                value=4.5
            )

            gr.Markdown("### 2. (可選) 指定地理範圍")
            use_geo_checkbox = gr.Checkbox(label="啟用地理範圍篩選", value=False)
            
            with gr.Row():
                min_lat_input = gr.Number(label="最小緯度 (南)", value=21.5)
                max_lat_input = gr.Number(label="最大緯度 (北)", value=25.5)
            with gr.Row():
                min_lon_input = gr.Number(label="最小經度 (西)", value=120.0)
                max_lon_input = gr.Number(label="最大經度 (東)", value=122.5)

            submit_btn = gr.Button("開始查詢", variant="primary")
            
        with gr.Column(scale=3):
            gr.Markdown("### 查詢結果")
            output_markdown = gr.Markdown("點擊「開始查詢」後，結果將會顯示於此。")

    # 綁定按鈕點擊事件
    submit_btn.click(
        fn=query_earthquakes,
        inputs=[
            starttime_input,
            endtime_input,
            magnitude_slider,
            use_geo_checkbox,
            min_lat_input, max_lat_input,
            min_lon_input, max_lon_input
        ],
        outputs=output_markdown
    )
    
    gr.Examples(
        examples=[
            [seven_days_ago.strftime('%Y-%m-%d'), today.strftime('%Y-%m-%d'), 6.0, False, 0, 0, 0, 0],
            ["2024-04-02", "2024-04-04", 5.5, True, 23.0, 25.0, 121.0, 122.5],
            ["2024-01-01", "2024-01-02", 7.0, True, 35.0, 38.0, 136.0, 140.0],
        ],
        inputs=[
            starttime_input,
            endtime_input,
            magnitude_slider,
            use_geo_checkbox,
            min_lat_input, max_lat_input,
            min_lon_input, max_lon_input
        ],
        outputs=output_markdown,
        fn=query_earthquakes,
        cache_examples=True # 讓範例結果快取，加速載入
    )

if __name__ == "__main__":
    demo.launch()