import matplotlib.pyplot as plt
import io
import streamlit as st

class Visualization:
    def plot_intervention_statistics(self, intervention_stats):
        sessions_held = intervention_stats['Intervention Sessions Held'].values[0]
        sessions_not_held = intervention_stats['Intervention Sessions Not Held'].values[0]

        fig, ax = plt.subplots()
        ax.bar(['Intervention Sessions'], [sessions_held], label='Held', color='#358E66')
        ax.bar(['Intervention Sessions'], [sessions_not_held], bottom=[sessions_held], label='Not Held', color='#91D6B8')

        ax.text(0, sessions_held / 2, str(sessions_held), ha='center', va='center', color='white', fontweight='bold', fontsize=14)
        ax.text(0, sessions_held + sessions_not_held / 2, str(sessions_not_held), ha='center', va='center', color='black', fontweight='bold', fontsize=14)

        ax.set_ylabel('Frequency')
        ax.set_title('Intervention Sessions Held vs Not Held', fontsize=16)
        handles, labels = ax.get_legend_handles_labels()
        ax.legend(handles[::-1], labels[::-1])

        ax.spines['top'].set_visible(False)
        ax.spines['right'].set_visible(False)
        
        st.pyplot(fig)
        return fig

    def plot_student_metrics(self, student_metrics_df, attendance_avg_stats, engagement_avg_stats):
        fig, ax = plt.subplots(figsize=(10, 6))
        bar_width = 0.35
        index = range(len(student_metrics_df))

                attendance_bars = ax.bar(
            [i - bar_width / 2 for i in index], 
            student_metrics_df['Attendance (%)'], 
            width=bar_width, label='Attendance (%)', 
            color='#005288', alpha=0.7
        )
        engagement_bars = ax.bar(
            [i + bar_width / 2 for i in index], 
            student_metrics_df['Engagement (%)'], 
            width=bar_width, label='Engagement (%)', 
            color='#3AB0FF', alpha=0.7
        )

        for bar in attendance_bars:
            height = bar.get_height()
            ax.text(bar.get_x() + bar.get_width() / 2, height, f'{height:.0f}%', ha='center', va='bottom', color='black')

        for bar in engagement_bars:
            height = bar.get_height()
            ax.text(bar.get_x() + bar.get_width() / 2, height, f'{height:.0f}%', ha='center', va='bottom', color='black')

        ax.axhline(y=attendance_avg_stats, color='#005288', linestyle='--', linewidth=1.5, label=f'Attendance Average: {attendance_avg_stats}%')
        ax.axhline(y=engagement_avg_stats, color='#3AB0FF', linestyle='--', linewidth=1.5, label=f'Engagement Average: {engagement_avg_stats}%')

        ax.set_xlabel('Student')
        ax.set_ylabel('Percentage (%)')
        ax.set_title('Student Attendance and Engagement Metrics')
        ax.legend(loc='upper right', frameon=False)
        ax.set_xticks(index)
        ax.set_xticklabels(student_metrics_df['Student'], rotation=0, ha='right')
        ax.set_ylim(0, 119)
        ax.yaxis.set_ticks(range(0, 119, 20))

        ax.spines['top'].set_visible(False)
        ax.spines['right'].set_visible(False)

        plt.tight_layout()
        st.pyplot(fig)
        return fig

    def download_chart(self, fig, filename):
        buffer = io.BytesIO()
        fig.savefig(buffer, format='png')
        buffer.seek(0)
        st.download_button(label="Download Chart", data=buffer, file_name=filename, mime='image/png', icon="📊", use_container_width=True)