import csv
import sys

import numpy as np

from .stuff import Particle


def _value(text):
    text = text.strip()
    if text == "nan":
        return np.nan
    return float(text)


def generate_particles_from_csv(filename):
    particles = []

    with open(filename, newline="") as fp:
        reader = csv.DictReader(fp, skipinitialspace=True)

        for row in reader:
            data = {
                name.strip(): value
                for name, value in row.items()
                if name is not None and name.strip()
            }

            mass = _value(data.get("mass", data.get("m", "1.0")))
            velocity = [
                _value(data.get(name, "0.0"))
                for name in ("v1", "v2", "v3")
            ]
            position = [
                _value(data.get(name, "0.0"))
                for name in ("p1", "p2", "p3")
            ]

            particles.append(
                Particle(mass=mass, velocity=velocity, position=position)
            )

    return particles


def generate_particles(filename):
    return generate_particles_from_csv(filename)


def particles_from_csv(filename):
    return generate_particles_from_csv(filename)


def load_particles_from_csv(filename):
    return generate_particles_from_csv(filename)


def _format_value(value):
    if isinstance(value, float) and np.isnan(value):
        return "nan"
    return str(value)


def particles_ascii_table(particles):
    headers = ["mass", "v1", "v2", "v3", "p1", "p2", "p3"]
    rows = []

    for particle in particles:
        rows.append(
            [
                _format_value(particle.mass),
                *[_format_value(value) for value in particle.velocity],
                *[_format_value(value) for value in particle.position],
            ]
        )

    widths = [
        max(len(header), *(len(row[index]) for row in rows))
        if rows else len(header)
        for index, header in enumerate(headers)
    ]

    def line(left, fill, join, right):
        return left + join.join(fill * (width + 2) for width in widths) + right

    def table_row(values):
        cells = [
            f" {value:<{width}} "
            for value, width in zip(values, widths)
        ]
        return "|" + "|".join(cells) + "|"

    output = [
        line("+", "-", "+", "+"),
        table_row(headers),
        line("+", "-", "+", "+"),
    ]
    output.extend(table_row(row) for row in rows)
    output.append(line("+", "-", "+", "+"))

    return "\n".join(output)


def particle_table(particles):
    return particles_ascii_table(particles)


def particles_to_ascii_table(particles):
    return particles_ascii_table(particles)


def display_particles(particles, file=None):
    table = particles_ascii_table(particles)
    print(table, file=file or sys.stdout)
    return table