#!/usr/bin/env python3
"""
    Routes
"""
import copy
import json
import os
from collections import OrderedDict
from datetime import datetime
from io import BytesIO
from pathlib import Path

from flask import Flask, jsonify, redirect, render_template, request, url_for

import tabulator
from validata_ui import app, error_messages
from validata_ui.util import (ValidataSource, flash_error, flash_info,
                              flash_success, flash_warning)
from validata_ui.validate_helper import ValidatorHelper
from validata_validate import csv_helpers
from validata_validate.loaders import custom_loaders


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.data, format=source.format, scheme=source.scheme,
                                                          custom_loaders=custom_loaders).delimiter
    with tabulator.Stream(source.data, 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_messages(errors, headers, schema):
    """ Translates and improve error messages """

    def error_message_default_func(error, headers, schema):
        """ Sets a new better error message """
        error['title'] = error['code']
        error['content'] = error.get('message', 'pas d\'information complémentaire')
        return error

    improved_errors = []

    for error in errors:

        improve_func = ERROR_MESSAGE_FUNC.get(error['code'], error_message_default_func)
        improved_errors.append(improve_func(error, headers, schema))

    return improved_errors


def contextualize(errors):
    """ add context to errors """

    def add_context(err):
        """ Adds context info based on row-nb presence """
        context = 'body' if 'row-number' in err and not err['row-number'] is None else 'table'
        return {**err, 'context': context}

    return list(map(add_context, 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]

    # Add context to errors
    errors = contextualize(report['table']['errors'])
    del report['table']['errors']

    # Provide better (french) messages
    errors = improve_messages(errors, headers, schema)

    # 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']['by_rows'] = rows

    return report


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

    try:
        goodtables_report = ValidatorHelper.validate(schema_code, **source.get_goodtables_source())
    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)

    validata_report = create_validata_report(goodtables_report, ValidatorHelper.schema(schema_code))

    # return jsonify(validata_report)

    # Complete report
    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=datetime.now().strftime('le %d/%m/%Y à %Hh%M'),
                           source=source, source_type=source.type, source_data=source_data,
                           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('/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 = request.args.get('url')
            if url is None or url == '':
                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, 'url'))

    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(bytes_data(f), f.filename, 'file'))

        return 'Bizarre, vous avez dit bizarre ?'