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

from backports.datetime_fromisoformat import MonkeyPatch
from commonmark import commonmark
from flask import make_response, redirect, render_template, request, url_for

import tabulator
from validata_core import csv_helpers, messages
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

MonkeyPatch.patch_fromisoformat()


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_ui_report(validata_core_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(validata_core_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['tag'] == 'structure':
            report['table']['errors']['structure'].append(err)
        else:
            report['table']['errors']['body'].append(err)

    # Checks if there are structure errors different to invalid-column-delimiter
    structure_errors = report['table']['errors']['structure']
    report['table']['do_display_body_errors'] = len(structure_errors) == 0 or \
        all(err['code'] == 'invalid-column-delimiter' for err in structure_errors)

    # Checks if a column comparison is needed
    header_errors = ('missing-headers', 'extra-headers', 'wrong-headers-order')
    structure_errors = [{**err, 'in_column_comp': err['code'] in header_errors} for err in structure_errors]
    report['table']['errors']['structure'] = structure_errors
    column_comparison_needed = any(err['in_column_comp'] == True for err in structure_errors)
    column_comparison_table = []
    if column_comparison_needed:
        column_comparison_table = []
        field_names = [f['name'] for f in schema_fields]
        has_case_errors = False
        for t in itertools.zip_longest(headers, field_names, fillvalue=''):
            status = 'ok' if t[0] == t[1] else 'ko'
            if not has_case_errors and status == 'ko' and t[0].lower() == t[1].lower():
                has_case_errors = True
            column_comparison_table.append((*t, status))
        info = {}
        info['table'] = column_comparison_table
        info['has_missing'] = len(headers) < len(field_names)
        info['has_case_errors'] = has_case_errors
        report['table']['column_comparison_info'] = info
    report['table']['column_comparison_needed'] = column_comparison_needed

    # 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

    # Sort by error names in statistics
    stats = report['table']['error-stats']
    code_title_map = messages.ERROR_MESSAGE_DEFAULT_TITLE
    for key in ('structure-errors', 'value-errors'):
        # convert dict into tuples with french title instead of error code
        # and sorts by title
        stats[key]['count-by-code'] = sorted([(code_title_map.get(k, k), v) for k, v in stats[key]['count-by-code'].items()],
                                             key=itemgetter(0))

    return report


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

    try:
        validata_core_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
    report_datetime = datetime.fromisoformat(validata_core_report['date']).astimezone()

    # Enhance validata_core_report
    validata_report = create_validata_ui_report(validata_core_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_datetime.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('scdl_validator', val_code=val_code))

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

    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)
        log.error("Command %r returned an error: %r", cmd, result.stdout.decode('utf-8'))
        if tmp_pdf_report.exists():
            tmp_pdf_report.unlink()
        return redirect(url_for('scdl_validator', val_code=val_code))

    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 ?'