import pandas as pd
import streamlit as st
import matplotlib.pyplot as plt
import matplotlib.font_manager as font_manager
import io
import base64
import os
from datetime import datetime, timedelta
import math
from pypinyin import lazy_pinyin, Style
from matplotlib.backends.backend_pdf import PdfPages

def get_font(size=14):
    """Loads a specific font file, falling back to a default if not found."""
    font_path = "simHei.ttc"
    if not os.path.exists(font_path):
        font_path = "SimHei.ttf"  # Fallback font
    return font_manager.FontProperties(fname=font_path, size=size)

def get_pinyin_abbr(text):
    """Gets the first letter of the Pinyin for the first two Chinese characters of a text."""
    if not text:
        return ""
    # Extract the first two Chinese characters
    chars = [c for c in text if '\u4e00' <= c <= '\u9fff']
    chars = chars[:2]
    # Get the first letter of the Pinyin
    pinyin_list = lazy_pinyin(chars, style=Style.FIRST_LETTER)
    return ''.join(pinyin_list).upper()

def process_schedule(file):
    """Processes the uploaded Excel file to extract and clean movie schedule data."""
    try:
        # Try to read the date from a specific cell
        date_df = pd.read_excel(file, header=None, skiprows=7, nrows=1, usecols=[3])
        date_str = pd.to_datetime(date_df.iloc[0, 0]).strftime('%Y-%m-%d')
        base_date = pd.to_datetime(date_str).date()
    except Exception:
        # Fallback to today's date if reading fails
        date_str = datetime.today().strftime('%Y-%m-%d')
        base_date = datetime.today().date()
    
    try:
        # Read the main schedule data
        df = pd.read_excel(file, header=9, usecols=[1, 2, 4, 5])
        df.columns = ['Hall', 'StartTime', 'EndTime', 'Movie']
        
        # Clean and process the data
        df['Hall'] = df['Hall'].ffill()
        df.dropna(subset=['StartTime', 'EndTime', 'Movie'], inplace=True)
        df['Hall'] = df['Hall'].astype(str).str.extract(r'(\d+号)')
        
        # Convert times to datetime objects
        df['StartTime_dt'] = pd.to_datetime(df['StartTime'], format='%H:%M', errors='coerce').apply(
            lambda t: t.replace(year=base_date.year, month=base_date.month, day=base_date.day) if pd.notnull(t) else t
        )
        df['EndTime_dt'] = pd.to_datetime(df['EndTime'], format='%H:%M', errors='coerce').apply(
            lambda t: t.replace(year=base_date.year, month=base_date.month, day=base_date.day) if pd.notnull(t) else t
        )
        
        # Handle overnight screenings
        df.loc[df['EndTime_dt'] < df['StartTime_dt'], 'EndTime_dt'] += timedelta(days=1)
        df = df.sort_values(['Hall', 'StartTime_dt'])
        
        # Merge consecutive screenings of the same movie
        merged_rows = []
        for hall, group in df.groupby('Hall'):
            group = group.sort_values('StartTime_dt')
            current = None
            for _, row in group.iterrows():
                if current is None:
                    current = row.copy()
                else:
                    if row['Movie'] == current['Movie']:
                        current['EndTime_dt'] = row['EndTime_dt'] # Extend the end time
                    else:
                        merged_rows.append(current)
                        current = row.copy()
            if current is not None:
                merged_rows.append(current)
        
        merged_df = pd.DataFrame(merged_rows)
        
        # Adjust start and end times
        merged_df['StartTime_dt'] = merged_df['StartTime_dt'] - timedelta(minutes=10)
        merged_df['EndTime_dt'] = merged_df['EndTime_dt'] - timedelta(minutes=5)
        
        merged_df['StartTime_str'] = merged_df['StartTime_dt'].dt.strftime('%H:%M')
        merged_df['EndTime_str'] = merged_df['EndTime_dt'].dt.strftime('%H:%M')
        
        return merged_df[['Hall', 'Movie', 'StartTime_str', 'EndTime_str']], date_str
    except Exception as e:
        st.error(f"An error occurred during data processing: {e}")
        return None, date_str

def create_print_layout(data, date_str):
    """Creates PNG and PDF layouts for the schedule, designed to fill an A4 page."""
    if data is None or data.empty:
        return None

    # --- Figure setup for both PNG and PDF ---
    # We create two figures to handle potential differences in rendering pipelines
    png_fig = plt.figure(figsize=(8.27, 11.69), dpi=300)
    png_ax = png_fig.add_subplot(111)
    png_ax.set_axis_off()
    png_fig.subplots_adjust(left=0.05, right=0.95, top=0.95, bottom=0.05)

    pdf_fig = plt.figure(figsize=(8.27, 11.69), dpi=300)
    pdf_ax = pdf_fig.add_subplot(111)
    pdf_ax.set_axis_off()
    pdf_fig.subplots_adjust(left=0.05, right=0.95, top=0.95, bottom=0.05)

    def process_figure(fig, ax):
        """The core logic to draw the schedule on a given matplotlib axis."""
        
        # --- Dynamic Calculation for Layout ---
        halls = sorted(data['Hall'].unique(), key=lambda h: int(h.replace('号','')))
        num_movies = len(data)
        num_halls = len(halls)
        
        # Total slots = one for each movie + one for each separator + 2 for padding
        totalA = num_movies + (num_halls - 1) + 2
        
        available_height = 0.95 # Usable portion of the page
        line_height = available_height / totalA
        
        # --- Dynamic Font Size Calculation ---
        # Base font size is proportional to the line height to ensure it fits
        # The factor (e.g., 60) is an empirical value that provides a good look
        dynamic_font_size = line_height * 60 
        
        main_font = get_font(dynamic_font_size)
        hall_font = get_font(dynamic_font_size * 1.2) # Make hall font slightly larger
        date_font = get_font(12)

        # Draw the date at the top
        ax.text(0.01, 0.98, date_str, ha='left', va='top', fontproperties=date_font, color='#A9A9A9', transform=ax.transAxes)
        
        y_position = 0.96 # Starting y-position from the top
        
        for i, hall in enumerate(halls):
            hall_data = data[data['Hall'] == hall]
            hall_num_text = f"{hall.replace('号', '')}"
            movie_count = 1
            
            # Draw Hall Number (only once per hall block)
            ax.text(0.03, y_position - (line_height / 2), hall_num_text,
                    fontsize=dynamic_font_size * 1.5, fontweight='bold', ha='center', va='center', 
                    fontproperties=hall_font, transform=ax.transAxes)

            for _, row in hall_data.iterrows():
                pinyin_abbr = get_pinyin_abbr(row['Movie'])
                
                # --- Content Layout per line ---
                # Column positions are defined as fractions of the page width
                x_movie_name = 0.48
                x_movie_num = 0.1
                x_pinyin = 0.18
                x_time = 0.82
                
                # 1. Movie Name (Right-aligned in its zone)
                ax.text(x_movie_name, y_position, row['Movie'],
                        ha='right', va='center', fontproperties=main_font, transform=ax.transAxes)

                # 2. Sequence Number (Left-aligned)
                ax.text(x_movie_num, y_position, f"{movie_count}.",
                        ha='left', va='center', fontproperties=main_font, transform=ax.transAxes)

                # 3. Pinyin Abbreviation (Left-aligned)
                ax.text(x_pinyin, y_position, pinyin_abbr,
                        ha='left', va='center', fontproperties=main_font, transform=ax.transAxes)

                # 4. Time (Left-aligned)
                time_str = f"{row['StartTime_str']} - {row['EndTime_str']}"
                ax.text(x_time, y_position, time_str,
                        ha='left', va='center', fontproperties=main_font, transform=ax.transAxes)
                
                y_position -= line_height
                movie_count += 1

            # Add a separator line after each hall block, except for the last one
            if i < num_halls - 1:
                y_position -= (line_height / 2) # small gap for the line
                ax.axhline(y=y_position, xmin=0.02, xmax=0.98, color='black', linewidth=0.8)
                y_position -= (line_height / 2) # gap after the line

    # --- Generate Outputs ---
    # Process both figures with the same logic
    process_figure(png_fig, png_ax)
    process_figure(pdf_fig, pdf_ax)
    
    # Save PNG to a buffer
    png_buffer = io.BytesIO()
    png_fig.savefig(png_buffer, format='png', bbox_inches='tight', pad_inches=0.05)
    png_buffer.seek(0)
    image_base64 = base64.b64encode(png_buffer.getvalue()).decode()
    plt.close(png_fig)
    
    # Save PDF to a buffer
    pdf_buffer = io.BytesIO()
    pdf_fig.savefig(pdf_buffer, format='pdf', bbox_inches='tight', pad_inches=0.05)
    pdf_buffer.seek(0)
    pdf_base64 = base64.b64encode(pdf_buffer.getvalue()).decode()
    plt.close(pdf_fig)
    
    return {
        'png': f"data:image/png;base64,{image_base64}",
        'pdf': f"data:application/pdf;base64,{pdf_base64}"
    }

def display_pdf(base64_pdf):
    """Generates the HTML to embed a PDF in Streamlit."""
    return f'<iframe src="{base64_pdf}" width="100%" height="800" type="application/pdf"></iframe>'

# --- Streamlit App Main ---
st.set_page_config(page_title="LED Screen Schedule Printer", layout="wide")
st.title("LED Screen Schedule Printer")

uploaded_file = st.file_uploader("Select '放映时间核对表.xls' file", type=["xls"])

if uploaded_file:
    with st.spinner("Processing file, please wait..."):
        schedule, date_str = process_schedule(uploaded_file)
        if schedule is not None:
            output = create_print_layout(schedule, date_str)
            
            # Use tabs for PDF and PNG previews
            tab1, tab2 = st.tabs(["PDF Preview", "PNG Preview"])
            
            with tab1:
                st.markdown(display_pdf(output['pdf']), unsafe_allow_html=True)
            
            with tab2:
                st.image(output['png'], use_container_width=True)
        else:
            st.error("Could not process the file. Please check if the file format and content are correct.")