app.py

from dash import Dash, dcc, html, Input, Output, State
import dash_bootstrap_components as dbc
import requests
import wbgapi as wb
import pandas as pd
import plotly.express as px
import datetime

def fetch_data(indicator):
    """Fetch data from World Bank API for a given indicator."""
    try:
        data = wb.data.DataFrame(indicator, 'all')
        data.reset_index(inplace=True)
        data.rename(columns={'economy': 'Country'}, inplace=True)
        data = data.melt(id_vars=['Country'], var_name='Year', value_name=indicator)
        data['Year'] = data['Year'].str.replace('YR', '').astype(int)
        return data
    except (wb.APIResponseError, requests.exceptions.RequestException) as e:
        print(f"Error fetching data: {e}")
        return pd.DataFrame()

def fetch_regions():
    """Fetch region data from World Bank API."""
    try:
        regions = wb.economy.DataFrame()
        regions.reset_index(inplace=True)
        regions = regions[['id', 'name', 'region']]
        regions.rename(columns={'id': 'Country', 'name': 'Country Name', 'region': 'Region'}, inplace=True)
        return regions
    except (wb.APIResponseError, requests.exceptions.RequestException) as e:
        print(f"Error fetching regions: {e}")
        return pd.DataFrame()

gdp_data = fetch_data('NY.GDP.MKTP.CD')
unemployment_data = fetch_data('SL.UEM.TOTL.ZS')
inflation_data = fetch_data('FP.CPI.TOTL')

regions = fetch_regions()

# Merge region data with country data
gdp_data = gdp_data.merge(regions, on='Country', how='left')
unemployment_data = unemployment_data.merge(regions, on='Country', how='left')
inflation_data = inflation_data.merge(regions, on='Country', how='left')

app = Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP, dbc.icons.FONT_AWESOME])
app.title = "GlobalEconomica"

def serve_layout(theme=dbc.themes.BOOTSTRAP):
    current_year = datetime.datetime.now().year
    return html.Div([
        dcc.Store(id='theme-store', data=theme),
        dcc.Location(id='url', refresh=False),
        html.Div(id='theme-container', children=[
            html.Div(className="header", children=[
                html.H1("GlobalEconomica", style={'textAlign': 'center'}),
                dbc.Row(
                    dbc.Col(
                        html.Div([
                            html.I(className="fa fa-sun", style={'marginRight': '10px'}),
                            dbc.Switch(id='theme-switch', className='mt-2', value=theme == dbc.themes.DARKLY),
                            html.I(className="fa fa-moon", style={'marginLeft': '10px'})
                        ], style={'display': 'flex', 'alignItems': 'center', 'justifyContent': 'center'}),
                        width={"size": 2, "offset": 5}
                    )
                )
            ]),
            html.Div(className="container-fluid", children=[
                dbc.Row(
                    dbc.Col(
                        dbc.Card([
                            dbc.CardBody([
                                html.H4("Select Country and Data Type", className="card-title"),
                                dcc.Dropdown(
                                    id='country-selector',
                                    options=[{'label': f"{row['Country Name']}", 'value': row['Country']} for _, row in regions.iterrows()],
                                    placeholder="Select a country or region",
                                    searchable=True
                                ),
                                dcc.Dropdown(
                                    id='data-type-selector',
                                    options=[
                                        {'label': 'GDP', 'value': 'GDP'},
                                        {'label': 'Unemployment Rate', 'value': 'Unemployment'},
                                        {'label': 'Inflation Rate', 'value': 'Inflation'}
                                    ],
                                    placeholder="Select data type"
                                ),
                                html.Div(id='year-input-container', children=[
                                    dcc.RangeSlider(
                                        id='year-range-slider',
                                        min=gdp_data['Year'].min(),
                                        max=gdp_data['Year'].max(),
                                        value=[gdp_data['Year'].min(), gdp_data['Year'].max()],
                                        marks={str(year): str(year) for year in range(gdp_data['Year'].min(), gdp_data['Year'].max() + 1, 5)},
                                        step=1,
                                        className='d-none d-md-block'
                                    ),
                                    html.Div([
                                       dbc.InputGroup([
                                          dbc.InputGroupText("Start Year"),
                                          dbc.Input(id='start-year-input', type='number', placeholder='Start Year', min=1960, max=current_year, step=1)
                                       ], className='mb-2'),
                                       dbc.InputGroup([
                                          dbc.InputGroupText("End Year"),
                                          dbc.Input(id='end-year-input', type='number', placeholder='End Year', min=1960, max=current_year, step=1)
                                       ], className='mb-2'),
                                       html.Div(id='year-input-error', style={'color': 'red'})
                                    ], className='d-block d-md-none')
                                ]),
                                html.Button("Download Data", id="download-data-button", className="btn btn-primary mt-3"),
                                dcc.Download(id="download-data")
                            ])
                        ], className="mx-auto", style={'marginTop': '25px'}),
                        width={"size": 12}
                    ),
                    className="justify-content-center align-items-center"
                ),
                dbc.Row(
                    dbc.Col(
                        dbc.Card([
                            dbc.CardBody([
                                 dcc.Graph(id='data-plot', style={'width': '100%', 'height': '500px', 'overflow': 'hidden'}, config={'responsive': True})
                            ], style={'padding': '15px'}),
                        ], className="mx-auto", style={'overflow': 'hidden'}),
                        width={"size": 12}
                    ),
                    className="justify-content-center align-items-center"
                )
            ])
        ])
    ])

app.layout = serve_layout

def get_data_by_type(data_type):
    """Return the appropriate dataset and column name based on the selected data type."""
    if data_type == 'GDP':
        return gdp_data, 'NY.GDP.MKTP.CD'
    elif data_type == 'Unemployment':
        return unemployment_data, 'SL.UEM.TOTL.ZS'
    elif data_type == 'Inflation':
        return inflation_data, 'FP.CPI.TOTL'
    return None, None

@app.callback(
    Output('data-plot', 'figure'),
    [Input('country-selector', 'value'),
     Input('data-type-selector', 'value'),
     Input('year-range-slider', 'value'),
     Input('start-year-input', 'value'),
     Input('end-year-input', 'value')]
)
def update_graph(selected_country, selected_data_type, selected_years, start_year, end_year):
    if not selected_country or not selected_data_type:
        return px.line(title="Select a country and data type to view trends")
    
    data, column_name = get_data_by_type(selected_data_type)
    if data is None:
        return px.line(title="Invalid data type selected")
    
    if start_year and end_year:
        selected_years = [start_year, end_year]
    
    country_data = data[(data['Country'] == selected_country) & 
                        (data['Year'] >= selected_years[0]) & 
                        (data['Year'] <= selected_years[1])].copy()
    
    if country_data.empty:
        return px.line(title=f"No data available for {selected_country}")
    
    if selected_data_type in ['Unemployment', 'Inflation']:
        country_data.loc[:, column_name] = country_data[column_name] / 100

    fig = px.line(country_data, x='Year', y=column_name, title=f'{selected_data_type} Trends for {selected_country}')
    
    if selected_data_type in ['Unemployment', 'Inflation']:
        fig.update_layout(yaxis_tickformat='.1%')

    return fig

@app.callback(
    Output('year-input-error', 'children'),
    [Input('start-year-input', 'value'),
     Input('end-year-input', 'value')]
)
def validate_years(start_year, end_year):
    current_year = datetime.datetime.now().year
    if start_year and (start_year < 1960 or start_year > current_year):
        return f"Start year must be between 1960 and {current_year}."
    if end_year and (end_year < 1960 or end_year > current_year):
        return f"End year must be between 1960 and {current_year}."
    if start_year and end_year and start_year > end_year:
        return "Start year must be less than or equal to end year."
    return ""

@app.callback(
    Output("download-data", "data"),
    Input("download-data-button", "n_clicks"),
    State('country-selector', 'value'),
    State('data-type-selector', 'value'),
    State('year-range-slider', 'value'),
    State('start-year-input', 'value'),
    State('end-year-input', 'value'),
    prevent_initial_call=True
)
def download_data(n_clicks, selected_country, selected_data_type, selected_years, start_year, end_year):
    if not selected_country or not selected_data_type:
        return None
    
    data, y_label = get_data_by_type(selected_data_type)
    if data is None:
        return None
    
    if start_year and end_year:
        selected_years = [start_year, end_year]
    
    country_data = data[(data['Country'] == selected_country) & 
                        (data['Year'] >= selected_years[0]) & 
                        (data['Year'] <= selected_years[1])]
    
    if country_data.empty:
        return None
    
    return dcc.send_data_frame(country_data.to_csv, f"{selected_country}_{selected_data_type}_data.csv")

@app.callback(
    Output('theme-store', 'data'),
    Input('theme-switch', 'value')
)
def toggle_theme(dark_mode):
    theme = dbc.themes.DARKLY if dark_mode else dbc.themes.BOOTSTRAP
    return theme

@app.callback(
    Output('theme-container', 'children'),
    Input('theme-store', 'data')
)
def update_theme(theme):
    return serve_layout(theme).children

if __name__ == '__main__':
    app.run_server(debug=True, host='0.0.0.0', port=8050)