#!/usr/bin/env python3
"""
    Routes
"""
import copy
import json
import subprocess
import time
from datetime import datetime
from io import BytesIO
from pathlib import Path
from urllib.parse import quote_plus

from commonmark import commonmark
from flask import make_response, redirect, render_template, request, url_for

import tabulator
from validata_core import csv_helpers
from validata_core.loaders import custom_loaders
from validata_ui import app
from validata_ui.ui_util import flash_error, flash_warning
from validata_ui.validata_util import ValidataSource
from validata_ui.validate_helper import ValidatorHelper


def extract_source_data(source: ValidataSource, preview_rows_nb=5):
    """ Computes table preview """

    def stringify(val):
        """ Transform value into string """
        return '' if val is None else str(val)

    header = None
    rows = []
    nb_rows = 0

    options = {}
    if source.format == "csv":
        options['delimiter'] = csv_helpers.detect_dialect(source.source, format=source.format, scheme=source.scheme,
                                                          custom_loaders=custom_loaders).delimiter
    with tabulator.Stream(source.source, format=source.format, scheme=source.scheme, custom_loaders=custom_loaders,
                          **options) as stream:
        for row in stream:
            if header is None:
                header = ['' if v is None else v for v in row]
            else:
                rows.append(list(map(stringify, row)))
                nb_rows += 1
    preview_rows_nb = min(preview_rows_nb, nb_rows)
    return {'header': header,
            'rows_nb': nb_rows,
            'data_rows': rows,
            'preview_rows_nb': preview_rows_nb,
            'preview_rows': rows[:preview_rows_nb]}


def improve_errors(errors):
    """Add context to errors, converts markdown content to HTML"""

    def improve_err(err):
        """Adds context info based on row-nb presence and converts content to HTML"""

        # Context
        update_keys = {
            'context': 'body' if 'row-number' in err and not err['row-number'] is None else 'table',
        }

        # markdown to HTML (with default values for 'title' and 'content')

        # Set default title if no title
        if not 'title' in err:
            update_keys['title'] = '[{}]'.format(err['code'])

        # Convert message to markdown only if no content
        # => for pre-checks errors
        if 'message' in err and not 'content' in err:
            update_keys['message'] = commonmark(err['message'])

        # Else, default message
        elif not 'message' in err or err['message'] is None:
            update_keys['message'] = '[{}]'.format(err['code'])

        # Message content
        md_content = '*content soon available*' if not 'content' in err else err['content']
        update_keys['content'] = commonmark(md_content)

        return {**err, **update_keys}

    return list(map(improve_err, errors))


def create_validata_report(goodtables_report, schema):
    """ Creates an error report easier to handle and display in templates:
        - only one table
        - errors are contextualized
        - error-counts is ok
        - errors are grouped by lines
        - errors are separated into "structure" and "body"
        - error messages are improved
    """
    report = copy.deepcopy(goodtables_report)

    # One table is enough
    del report['table-count']
    report['table'] = report['tables'][0]
    del report['tables']
    del report['table']['error-count']
    del report['table']['time']
    del report['table']['valid']
    del report['valid']
    # use _ instead of - to ease information picking in jinja2 template
    report['table']['row_count'] = report['table']['row-count']

    # Handy col_count info
    headers = report['table'].get('headers', [])
    report['table']['col_count'] = len(headers)

    # Computes column info
    schema_fields = schema.get('fields', [])
    fields_dict = {f['name']: (f.get('title', 'titre non défini'), f.get('description', '')) for f in schema_fields}
    report['table']['headers_title'] = [fields_dict[h][0] if h in fields_dict else 'colonne inconnue' for h in headers]
    report['table']['headers_description'] = [fields_dict[h][1]
                                              if h in fields_dict else 'Cette colonne n\'est pas définie dans le schema' for h in headers]

    # Provide better (french) messages
    errors = improve_errors(report['table']['errors'])
    del report['table']['errors']

    # Count errors
    report['error_count'] = len(errors)
    del report['error-count']

    # Then group them in 2 groups : structure and body
    report['table']['errors'] = {'structure': [], 'body': []}
    for err in errors:
        if err['context'] != 'body':
            report['table']['errors']['structure'].append(err)
        else:
            report['table']['errors']['body'].append(err)

    # Checks if there are structure errors different to invalid-column-delimiter
    report['table']['display_body_errors'] = all(err['code'] == 'invalid-column-delimiter'
                                                 for err in report['table']['errors']['structure'])

    # Group body errors by row id
    rows = []
    current_row_id = 0
    for err in report['table']['errors']['body']:
        if not 'row-number' in err:
            print('ERR', err)
        row_id = err['row-number']
        del err['row-number']
        del err['context']
        if row_id != current_row_id:
            current_row_id = row_id
            rows.append({'row_id': current_row_id, 'errors': {}})

        column_id = err.get('column-number')
        if column_id is not None:
            del err['column-number']
            rows[-1]['errors'][column_id] = err
        else:
            rows[-1]['errors']['row'] = err
    report['table']['errors']['body_by_rows'] = rows

    return report


def validate(schema_code, source: ValidataSource):
    """ Validate source and display report """

    try:
        goodtables_report = ValidatorHelper.validate(
            schema_code=schema_code,
            force_strings=True,
            **source.get_tabulator_params(),
        )
    except tabulator.exceptions.FormatError:
        flash_error('Erreur : format de fichier non supporté')
        return redirect(url_for('scdl_validator', val_code=schema_code))

    source_data = extract_source_data(source)

    # handle report date
    date_str = goodtables_report['date']
    report_date = datetime.strptime(date_str[:date_str.find('.')], '%Y-%m-%dT%H:%M:%S')

    # Enhance goodtables_report
    validata_report = create_validata_report(goodtables_report, ValidatorHelper.schema(schema_code).descriptor)

    # Display report to the user
    val_info = ValidatorHelper.schema_info(schema_code)
    return render_template('validation_report.html', title='Rapport de validation',
                           val_info=ValidatorHelper.schema_info(schema_code), report=validata_report,
                           validation_date=report_date.strftime('le %d/%m/%Y à %Hh%M'),
                           source=source, source_type=source.type, source_data=source_data,
                           print_mode=request.args.get('print', 'false') == 'true',
                           report_str=json.dumps(validata_report, sort_keys=True, indent=2),
                           breadcrumbs=[{'url': url_for('home'), 'title': 'Accueil'},
                                        {'url': url_for('scdl_validator', val_code=schema_code),
                                         'title': val_info['title']}])


def bytes_data(f):
    """ Gets bytes data from Werkzeug FileStorage instance """
    iob = BytesIO()
    f.save(iob)
    iob.seek(0)
    return iob.getvalue()


# Routes


@app.route('/')
def home():
    """ Home page """
    validators = ValidatorHelper.schema_info_list()
    flash_warning('Ce service est fourni en mode beta - certains problèmes peuvent subsister - nous mettons tout en œuvre pour améliorer son fonctionnement en continu')
    return render_template('home.html', title='Accueil', validators=validators)


@app.route('/validators')
def validators():
    """ No validators page """
    return redirect(url_for('home'))


@app.route('/pdf/<val_code>')
def pdf_report(val_code):
    """PDF report generation"""
    err_prefix = 'Erreur de génération du rapport PDF: '

    if not ValidatorHelper.schema_exist(val_code):
        flash_error(err_prefix + 'schéma inconnu')
        return redirect(url_for('home'))

    url_param = request.args.get('url')
    if not url_param:
        flash_error(err_prefix+'url non fournie')
        return redirect(url_for('home'))

    validation_url = '{}?input=url&print=true&url={}'.format(url_for('scdl_validator', val_code=val_code, _external=True),
                                                             quote_plus(url_param))

    # temporary pdf_report.pdf filename
    tmp_pdf_report = Path('/tmp') / 'validata_{}_{}_pdf_report.pdf'.format(val_code, str(time.time()))

    cmd = ['chromium', '--headless', '--disable-gpu',
           '--print-to-pdf={}'.format(str(tmp_pdf_report)), validation_url]
    result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    if result.returncode != 0:
        flash_error(err_prefix + result.stdout)
        if tmp_pdf_report.exists():
            tmp_pdf_report.unlink()
        return redirect(url_for('home'))

    response = make_response(tmp_pdf_report.open('rb').read())
    response.headers.set('Content-disposition', 'attachment', filename='report.pdf')
    response.headers.set('Content-type', 'application/pdf')
    response.headers.set('Content-length', tmp_pdf_report.stat().st_size)

    tmp_pdf_report.unlink()

    return response


@app.route('/validators/<val_code>', methods=['GET', 'POST'])
def scdl_validator(val_code):
    """ Validator page """

    if not ValidatorHelper.schema_exist(val_code):
        flash_error('Validateur [{}] inconnu'.format(val_code))
        return redirect(url_for('home'))

    if request.method == 'GET':

        val_info = ValidatorHelper.schema_info(val_code)
        input_param = request.args.get('input')

        # First form display
        if input_param is None or input_param not in ('url', 'example'):
            return render_template('validation_form.html', title=val_info['title'],
                                   val_info=val_info,
                                   breadcrumbs=[{'url': url_for('home'), 'title': 'Accueil'}, ])

        # Process URL
        else:
            url_param = request.args.get('url')
            if url_param is None or url_param == '':
                flash_error("Vous n'avez pas indiqué d'url à valider")
                return redirect(url_for('scdl_validator', val_code=val_code))
            return validate(val_code, ValidataSource('url', url_param, url_param))

    else:  # POST
        input_param = request.form.get('input')
        if input_param is None:
            flash_error('Aucun fichier à valider')
            return redirect(url_for('scdl_validator', val_code=val_code))

        # File validation
        if input_param == 'file':
            f = request.files.get('file')
            if f is None:
                flash_warning("Vous n'avez pas indiqué de fichier à valider")
                return redirect(url_for('scdl_validator', val_code=val_code))

            return validate(val_code, ValidataSource('file', f.filename, bytes_data(f)))

        return 'Bizarre, vous avez dit bizarre ?'