table.py

import csv
from dataclasses import dataclass
from flask import Response, url_for
from html import escape
import io
from markupsafe import Markup
from typing import Sequence, Optional, Iterable
import urllib.parse
import werkzeug.exceptions

import mo.csv
import mo.db as db
from mo.web import app


@dataclass
class Column:
    key: str                # Jméno klíče ve slovnících
    name: str               # Název v hlavičce CSV
    title: str              # Titulek v HTML tabulkách

    def __init__(self, key: str, name: Optional[str] = None, title: Optional[str] = None):
        self.key = key
        self.name = name or key
        self.title = title or self.name


class Cell:
    """Buňka tabulky může mít dvě verze: textovou a HTML."""
    text: str

    def __init__(self, text: str):
        self.text = text

    def __str__(self) -> str:
        return self.text

    def to_html(self) -> str:
        return escape(self.text)


class CellLink(Cell):
    url: str
    hint: Optional[str]

    def __init__(self, text: str, url: str, hint: Optional[str] = None):
        Cell.__init__(self, text)
        self.url = url
        self.hint = hint

    def to_html(self) -> str:
        a = '<a href="' + escape(self.url) + '"'
        if self.hint:
            a += ' title="' + escape(self.hint) + '"'
        return a + '>' + escape(self.text) + '</a>'


class Table:
    columns: Sequence[Column]
    rows: Iterable[dict]
    filename: str

    def __init__(self, columns: Sequence[Column], rows: Iterable[dict], filename: str):
        self.columns = columns
        self.rows = rows
        self.filename = filename

    def to_html(self) -> str:
        tab = ['<table class=data>', '<tr>']

        for c in self.columns:
            tab.append(f'\t<th>{c.title}')

        for r in self.rows:
            tab.append('<tr>')
            for c in self.columns:
                val = r.get(c.key)
                if isinstance(val, Cell):
                    vals = val.to_html()
                else:
                    vals = escape(str(val))
                tab.append(f'\t<td>{vals}')

        tab.append('</table>')
        tab.append("<p>Stáhnout jako <a href='?format=csv'>CSV</a> nebo <a href='?format=tsv'>TSV</a>.")
        return Markup("\n".join(tab))

    def to_csv(self, dialect: str) -> str:
        out = io.StringIO()
        writer = csv.writer(out, dialect=dialect)

        header = [c.name for c in self.columns]
        writer.writerow(header)

        for row in self.rows:
            r = [row.get(c.key) for c in self.columns]
            writer.writerow(r)

        return out.getvalue()

    def to_csv_stream(self, dialect: str) -> Iterable[str]:
        out = io.StringIO()
        writer = csv.writer(out, dialect=dialect)

        header = [c.name for c in self.columns]
        writer.writerow(header)

        nrows = 0
        for row in self.rows:
            r = [row.get(c.key) for c in self.columns]
            writer.writerow(r)

            nrows += 1
            if nrows >= 100:
                yield out.getvalue()
                out.seek(0)
                out.truncate()
                nrows = 0

        yield out.getvalue()

    def send_as(self, format: str, streaming: bool = False) -> Response:
        if format == 'csv':
            dialect = 'excel'
            ctype = 'text/csv; charset=utf=8'
            filename = self.filename + '.csv'
        elif format == 'tsv':
            dialect = 'tsv'
            ctype = 'text/tab-separated-values; charset=utf=8'
            filename = self.filename + '.tsv'
        else:
            raise werkzeug.exceptions.NotFound()

        if streaming:
            resp = Response(self.to_csv_stream(dialect=dialect))
        else:
            out = self.to_csv(dialect=dialect)
            resp = app.make_response(out)

        resp.content_type = ctype
        resp.headers.add('Content-Disposition', f'attachment; filename={filename}')
        return resp


# Pomocné funkce na generování různých typů odkazů

def cell_email_link(user: db.User) -> CellLink:
    return CellLink(user.email, 'mailto:' + urllib.parse.quote(user.email, safe='@'))


def cell_user_link(user: db.User, text: str) -> CellLink:
    return CellLink(text, url_for('org_user', id=user.user_id))


def cell_place_link(place: db.Place, text: str) -> CellLink:
    return CellLink(text, url_for('org_place', id=place.place_id), hint=place.name)