#!/usr/bin/python3
import argparse
import geopandas
import psycopg2
import matplotlib.pyplot as plt

from matplotlib import rc

#CMAP = 'Set3'
CMAP = 'tab20c'
INCH = 25.4  # mm
BOUNDS = ('xmin', 'ymin', 'xmax', 'ymax')
BLACK, GREEN, ORANGE, PURPLE = '#000000', '#1b9e77', '#d95f02', '#7570b3'
PSQL_CREDS = "host=127.0.0.1 dbname=osm user=osm password=osm"

def plt_size(string):
    if not string:
        return None
    try:
        w, h = string.split("x")
        return float(w) / INCH, float(h) / INCH
    except Exception as e:
        raise argparse.ArgumentTypeError from e


def parse_args():
    parser = argparse.ArgumentParser(
            description='Convert geopackage to an image')
    parser.add_argument('--group1-table')
    parser.add_argument('--group1-where')
    parser.add_argument('--group1-cmap', type=bool)

    parser.add_argument('--group2-table')
    parser.add_argument('--group2-where')
    parser.add_argument('--group2-cmap', type=bool)

    parser.add_argument('--group3-table')
    parser.add_argument('--group3-where')
    parser.add_argument('--group3-cmap', type=bool)

    parser.add_argument('-o', '--outfile', metavar='<file>')
    parser.add_argument(
            '--size', type=plt_size, help='Figure size in mm (WWxHH)')
    parser.add_argument('--clip', type=float, nargs=4, metavar=BOUNDS)
    return parser.parse_args()


def read_layer(table, maybe_where=None):
    if not table:
        return
    conn = psycopg2.connect(PSQL_CREDS)
    sql = "SELECT way FROM %s" % table
    if maybe_where:
        sql += " WHERE %s" % maybe_where
    return geopandas.read_postgis(sql, con=conn, geom_col='way')


def main():
    args = parse_args()
    group1 = read_layer(args.group1_table, args.group1_where)
    group2 = read_layer(args.group2_table, args.group2_where)
    group3 = read_layer(args.group3_table, args.group3_where)
    c1 = {'cmap': CMAP} if args.group1_cmap else {'color': BLACK}
    c2 = {'cmap': CMAP} if args.group2_cmap else {'color': ORANGE}
    c3 = {'cmap': CMAP} if args.group3_cmap else {'color': GREEN}

    rc('text', usetex=True)
    fig, ax = plt.subplots()
    if args.size:
        fig.set_size_inches(args.size)
    if c := args.clip:
        ax.set_xlim(left=c[0], right=c[2])
        ax.set_ylim(bottom=c[1], top=c[3])

    group1 is not None and group1.plot(ax=ax, **c1)
    group2 is not None and group2.plot(ax=ax, **c2)
    group3 is not None and group3.plot(ax=ax, **c3)

    ax.axis('off')
    ax.margins(0, 0)
    if args.outfile:
        fig.savefig(args.outfile, bbox_inches='tight', dpi=600)
    else:
        plt.show()


if __name__ == '__main__':
    main()