# -*- coding: utf-8 -*-
##############################################################################
#
#    OpenERP, Open Source Management Solution
#    Copyright (C) 2014-Today OpenERP SA (<http://www.openerp.com>).
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

from openerp.osv import osv
from openerp.tools import config
from openerp.tools.translate import _
from openerp.addons.web.http import request
from openerp.tools.safe_eval import safe_eval as eval

import re
import time
import base64
import logging
import tempfile
import lxml.html
import cStringIO
import subprocess
from distutils.version import LooseVersion
from functools import partial
from pyPdf import PdfFileWriter, PdfFileReader


_logger = logging.getLogger(__name__)


"""Check the presence of wkhtmltopdf and return its version at OpnerERP start-up."""
wkhtmltopdf_state = 'install'
try:
    process = subprocess.Popen(
        ['wkhtmltopdf', '--version'], stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
except OSError:
    _logger.info('You need wkhtmltopdf to print a pdf version of the reports.')
else:
    out, err = process.communicate()
    version = re.search('([0-9.]+)', out).group(0)
    if LooseVersion(version) < LooseVersion('0.12.0'):
        _logger.info('Upgrade wkhtmltopdf to (at least) 0.12.0')
        wkhtmltopdf_state = 'upgrade'
    else:
        wkhtmltopdf_state = 'ok'

    if config['workers'] == 1:
        _logger.info('You need to start OpenERP with at least two workers to print a pdf version of the reports.')
        wkhtmltopdf_state = 'workers'


class Report(osv.Model):
    _name = "report"
    _description = "Report"

    public_user = None

    #--------------------------------------------------------------------------
    # Extension of ir_ui_view.render with arguments frequently used in reports
    #--------------------------------------------------------------------------
    def render(self, cr, uid, ids, template, values=None, context=None):
        """Allow to render a QWeb template python-side. This function returns the 'ir.ui.view'
        render but embellish it with some variables/methods used in reports.

        :param values: additionnal methods/variables used in the rendering
        :returns: html representation of the template
        """
        if values is None:
            values = {}

        if context is None:
            context = {}

        view_obj = self.pool['ir.ui.view']

        def translate_doc(doc_id, model, lang_field, template):
            """Helper used when a report should be translated into a specific lang.

            <t t-foreach="doc_ids" t-as="doc_id">
            <t t-raw="translate_doc(doc_id, doc_model, 'partner_id.lang', account.report_invoice_document')"/>
            </t>

            :param doc_id: id of the record to translate
            :param model: model of the record to translate
            :param lang_field': field of the record containing the lang
            :param template: name of the template to translate into the lang_field
            """
            ctx = context.copy()
            doc = self.pool[model].browse(cr, uid, doc_id, context=ctx)
            qcontext = values.copy()
            # Do not force-translate if we chose to display the report in a specific lang
            if ctx.get('translatable') is True:
                qcontext['o'] = doc
            else:
                # Reach the lang we want to translate the doc into
                ctx['lang'] = eval('doc.%s' % lang_field, {'doc': doc})
                qcontext['o'] = self.pool[model].browse(cr, uid, doc_id, context=ctx)
            return view_obj.render(cr, uid, template, qcontext, context=ctx)

        user = self.pool['res.users'].browse(cr, uid, uid)
        website = None
        if request and hasattr(request, 'website'):
            website = request.website
            context.update(translatable=context.get('lang') != request.website.default_lang_code)
        values.update(
            time=time,
            translate_doc=translate_doc,
            editable=True,  # Will active inherit_branding
            user=user,
            res_company=user.company_id,
            website=website,
            editable_no_editor=True,
        )
        return view_obj.render(cr, uid, template, values, context=context)

    #--------------------------------------------------------------------------
    # Main report methods
    #--------------------------------------------------------------------------
    def get_html(self, cr, uid, ids, report_name, data=None, context=None):
        """This method generates and returns html version of a report.
        """
        # If the report is using a custom model to render its html, we must use it.
        # Otherwise, fallback on the generic html rendering.
        try:
            report_model_name = 'report.%s' % report_name
            particularreport_obj = self.pool[report_model_name]
            return particularreport_obj.render_html(cr, uid, ids, data=data, context=context)
        except KeyError:
            report = self._get_report_from_name(cr, uid, report_name)
            report_obj = self.pool[report.model]
            docs = report_obj.browse(cr, uid, ids, context=context)
            docargs = {
                'doc_ids': ids,
                'doc_model': report.model,
                'docs': docs,
            }
            return self.render(cr, uid, [], report.report_name, docargs, context=context)

    def get_pdf(self, cr, uid, ids, report_name, html=None, data=None, context=None):
        """This method generates and returns pdf version of a report.
        """
        if context is None:
            context = {}

        if html is None:
            html = self.get_html(cr, uid, ids, report_name, data=data, context=context)

        html = html.decode('utf-8')  # Ensure the current document is utf-8 encoded.

        # Get the ir.actions.report.xml record we are working on.
        report = self._get_report_from_name(cr, uid, report_name)
        # Check if we have to save the report or if we have to get one from the db.
        save_in_attachment = self._check_attachment_use(cr, uid, ids, report)
        # Get the paperformat associated to the report, otherwise fallback on the company one.
        if not report.paperformat_id:
            user = self.pool['res.users'].browse(cr, uid, uid)
            paperformat = user.company_id.paperformat_id
        else:
            paperformat = report.paperformat_id

        # Preparing the minimal html pages
        subst = "<script src='/report/static/src/js/subst.js'></script> "
        css = ''  # Will contain local css
        headerhtml = []
        contenthtml = []
        footerhtml = []
        base_url = self.pool['ir.config_parameter'].get_param(cr, uid, 'web.base.url')

        # Minimal page renderer
        view_obj = self.pool['ir.ui.view']
        render_minimal = partial(view_obj.render, cr, uid, 'report.minimal_layout', context=context)

        # The received html report must be simplified. We convert it in a xml tree
        # in order to extract headers, bodies and footers.
        try:
            root = lxml.html.fromstring(html)

            for node in root.xpath("//html/head/style"):
                css += node.text

            for node in root.xpath("//div[@class='header']"):
                body = lxml.html.tostring(node)
                header = render_minimal(dict(css=css, subst=subst, body=body, base_url=base_url))
                headerhtml.append(header)

            for node in root.xpath("//div[@class='footer']"):
                body = lxml.html.tostring(node)
                footer = render_minimal(dict(css=css, subst=subst, body=body, base_url=base_url))
                footerhtml.append(footer)

            for node in root.xpath("//div[@class='page']"):
                # Previously, we marked some reports to be saved in attachment via their ids, so we
                # must set a relation between report ids and report's content. We use the QWeb
                # branding in order to do so: searching after a node having a data-oe-model
                # attribute with the value of the current report model and read its oe-id attribute
                oemodelnode = node.find(".//*[@data-oe-model='%s']" % report.model)
                if oemodelnode is not None:
                    reportid = oemodelnode.get('data-oe-id')
                    if reportid:
                        reportid = int(reportid)
                else:
                    reportid = False

                body = lxml.html.tostring(node)
                reportcontent = render_minimal(dict(css=css, subst='', body=body, base_url=base_url))

                # FIXME: imo the best way to extract record id from html reports is by using the
                # qweb branding. As website editor is not yet splitted in a module independant from
                # website, when we print a unique report we can use the id passed in argument to
                # identify it.
                if ids and len(ids) == 1:
                    reportid = ids[0]

                contenthtml.append(tuple([reportid, reportcontent]))

        except lxml.etree.XMLSyntaxError:
            contenthtml = []
            contenthtml.append(html)
            save_in_attachment = {}  # Don't save this potentially malformed document

        # Get paperformat arguments set in the root html tag. They are prioritized over
        # paperformat-record arguments.
        specific_paperformat_args = {}
        for attribute in root.items():
            if attribute[0].startswith('data-report-'):
                specific_paperformat_args[attribute[0]] = attribute[1]

        # Run wkhtmltopdf process
        pdf = self._generate_wkhtml_pdf(
            cr, uid, headerhtml, footerhtml, contenthtml, context.get('landscape'),
            paperformat, specific_paperformat_args, save_in_attachment
        )
        return pdf

    def get_action(self, cr, uid, ids, report_name, data=None, context=None):
        """Return an action of type ir.actions.report.xml.

        :param ids: Ids of the records to print (if not used, pass an empty list)
        :param report_name: Name of the template to generate an action for
        """
        if ids:
            if not isinstance(ids, list):
                ids = [ids]
            context['active_ids'] = ids

        report_obj = self.pool['ir.actions.report.xml']
        idreport = report_obj.search(cr, uid, [('report_name', '=', report_name)], context=context)
        try:
            report = report_obj.browse(cr, uid, idreport[0], context=context)
        except IndexError:
            raise osv.except_osv(
                _('Bad Report Reference'),
                _('This report is not loaded into the database: %s.' % report_name)
            )

        return {
            'context': context,
            'data': data,
            'type': 'ir.actions.report.xml',
            'report_name': report.report_name,
            'report_type': report.report_type,
            'report_file': report.report_file,
            'context': context,
        }

    #--------------------------------------------------------------------------
    # Report generation helpers
    #--------------------------------------------------------------------------
    def _check_attachment_use(self, cr, uid, ids, report):
        """ Check attachment_use field. If set to true and an existing pdf is already saved, load
        this one now. Else, mark save it.
        """
        save_in_attachment = {}
        if report.attachment_use is True:
            save_in_attachment['model'] = report.model
            save_in_attachment['loaded_documents'] = {}

            for record_id in ids:
                obj = self.pool[report.model].browse(cr, uid, record_id)
                filename = eval(report.attachment, {'object': obj, 'time': time})

                if filename is False:  # May be false if, for instance, the record is in draft state
                    continue
                else:
                    alreadyindb = [('datas_fname', '=', filename),
                                   ('res_model', '=', report.model),
                                   ('res_id', '=', record_id)]

                    attach_ids = self.pool['ir.attachment'].search(cr, uid, alreadyindb)
                    if attach_ids:
                        # Add the loaded pdf in the loaded_documents list
                        pdf = self.pool['ir.attachment'].browse(cr, uid, attach_ids[0]).datas
                        pdf = base64.decodestring(pdf)
                        save_in_attachment['loaded_documents'][record_id] = pdf
                        _logger.info('The PDF document %s was loaded from the database' % filename)
                    else:
                        # Mark current document to be saved
                        save_in_attachment[record_id] = filename
        return save_in_attachment

    def _check_wkhtmltopdf(self):
        return wkhtmltopdf_state

    def _generate_wkhtml_pdf(self, cr, uid, headers, footers, bodies, landscape, paperformat, spec_paperformat_args=None, save_in_attachment=None):
        """Execute wkhtmltopdf as a subprocess in order to convert html given in input into a pdf
        document.

        :param header: list of string containing the headers
        :param footer: list of string containing the footers
        :param bodies: list of string containing the reports
        :param landscape: boolean to force the pdf to be rendered under a landscape format
        :param paperformat: ir.actions.report.paperformat to generate the wkhtmltopf arguments
        :param specific_paperformat_args: dict of prioritized paperformat arguments
        :param save_in_attachment: dict of reports to save/load in/from the db
        :returns: Content of the pdf as a string
        """
        command = ['wkhtmltopdf']
        command_args = []
        tmp_dir = tempfile.gettempdir()

        # Passing the cookie to wkhtmltopdf in order to resolve internal links.
        try:
            if request:
                command_args.extend(['--cookie', 'session_id', request.session.sid])
        except AttributeError:
            pass

        # Wkhtmltopdf arguments
        command_args.extend(['--quiet'])  # Less verbose error messages
        if paperformat:
            # Convert the paperformat record into arguments
            command_args.extend(self._build_wkhtmltopdf_args(paperformat, spec_paperformat_args))

        # Force the landscape orientation if necessary
        if landscape and '--orientation' in command_args:
            command_args_copy = list(command_args)
            for index, elem in enumerate(command_args_copy):
                if elem == '--orientation':
                    del command_args[index]
                    del command_args[index]
                    command_args.extend(['--orientation', 'landscape'])
        elif landscape and not '--orientation' in command_args:
            command_args.extend(['--orientation', 'landscape'])

        # Execute WKhtmltopdf
        pdfdocuments = []
        for index, reporthtml in enumerate(bodies):
            local_command_args = []
            pdfreport = tempfile.NamedTemporaryFile(suffix='.pdf', prefix='report.tmp.', mode='w+b')

            # Directly load the document if we already have it
            if save_in_attachment and save_in_attachment['loaded_documents'].get(reporthtml[0]):
                pdfreport.write(save_in_attachment['loaded_documents'].get(reporthtml[0]))
                pdfreport.seek(0)
                pdfdocuments.append(pdfreport)
                continue

            # Wkhtmltopdf handles header/footer as separate pages. Create them if necessary.
            if headers:
                head_file = tempfile.NamedTemporaryFile(suffix='.html', prefix='report.header.tmp.', dir=tmp_dir, mode='w+')
                head_file.write(headers[index])
                head_file.seek(0)
                local_command_args.extend(['--header-html', head_file.name])
            if footers:
                foot_file = tempfile.NamedTemporaryFile(suffix='.html', prefix='report.footer.tmp.', dir=tmp_dir, mode='w+')
                foot_file.write(footers[index])
                foot_file.seek(0)
                local_command_args.extend(['--footer-html', foot_file.name])

            # Body stuff
            content_file = tempfile.NamedTemporaryFile(suffix='.html', prefix='report.body.tmp.', dir=tmp_dir, mode='w+')
            content_file.write(reporthtml[1])
            content_file.seek(0)

            try:
                wkhtmltopdf = command + command_args + local_command_args
                wkhtmltopdf += [content_file.name] + [pdfreport.name]

                process = subprocess.Popen(wkhtmltopdf, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                out, err = process.communicate()

                if process.returncode not in [0, 1]:
                    raise osv.except_osv(_('Report (PDF)'),
                                         _('Wkhtmltopdf failed (error code: %s). '
                                           'Message: %s') % (str(process.returncode), err))

                # Save the pdf in attachment if marked
                if reporthtml[0] is not False and save_in_attachment.get(reporthtml[0]):
                    attachment = {
                        'name': save_in_attachment.get(reporthtml[0]),
                        'datas': base64.encodestring(pdfreport.read()),
                        'datas_fname': save_in_attachment.get(reporthtml[0]),
                        'res_model': save_in_attachment.get('model'),
                        'res_id': reporthtml[0],
                    }
                    self.pool['ir.attachment'].create(cr, uid, attachment)
                    _logger.info('The PDF document %s is now saved in the '
                                 'database' % attachment['name'])

                pdfreport.seek(0)
                pdfdocuments.append(pdfreport)

                if headers:
                    head_file.close()
                if footers:
                    foot_file.close()
            except:
                raise

        # Return the entire document
        if len(pdfdocuments) == 1:
            content = pdfdocuments[0].read()
            pdfdocuments[0].close()
        else:
            content = self._merge_pdf(pdfdocuments)

        return content

    def _get_report_from_name(self, cr, uid, report_name):
        """Get the first record of ir.actions.report.xml having the ``report_name`` as value for
        the field report_name.
        """
        report_obj = self.pool['ir.actions.report.xml']
        qwebtypes = ['qweb-pdf', 'qweb-html']
        conditions = [('report_type', 'in', qwebtypes), ('report_name', '=', report_name)]
        idreport = report_obj.search(cr, uid, conditions)[0]
        return report_obj.browse(cr, uid, idreport)

    def _build_wkhtmltopdf_args(self, paperformat, specific_paperformat_args=None):
        """Build arguments understandable by wkhtmltopdf from a report.paperformat record.

        :paperformat: report.paperformat record
        :specific_paperformat_args: a dict containing prioritized wkhtmltopdf arguments
        :returns: list of string representing the wkhtmltopdf arguments
        """
        command_args = []
        if paperformat.format and paperformat.format != 'custom':
            command_args.extend(['--page-size', paperformat.format])

        if paperformat.page_height and paperformat.page_width and paperformat.format == 'custom':
            command_args.extend(['--page-width', str(paperformat.page_width) + 'mm'])
            command_args.extend(['--page-height', str(paperformat.page_height) + 'mm'])

        if specific_paperformat_args and specific_paperformat_args.get('data-report-margin-top'):
            command_args.extend(['--margin-top', str(specific_paperformat_args['data-report-margin-top'])])
        elif paperformat.margin_top:
            command_args.extend(['--margin-top', str(paperformat.margin_top)])

        if specific_paperformat_args and specific_paperformat_args.get('data-report-dpi'):
            command_args.extend(['--dpi', str(specific_paperformat_args['data-report-dpi'])])
        elif paperformat.dpi:
            command_args.extend(['--dpi', str(paperformat.dpi)])

        if specific_paperformat_args and specific_paperformat_args.get('data-report-header-spacing'):
            command_args.extend(['--header-spacing', str(specific_paperformat_args['data-report-header-spacing'])])
        elif paperformat.header_spacing:
            command_args.extend(['--header-spacing', str(paperformat.header_spacing)])

        if paperformat.margin_left:
            command_args.extend(['--margin-left', str(paperformat.margin_left)])
        if paperformat.margin_bottom:
            command_args.extend(['--margin-bottom', str(paperformat.margin_bottom)])
        if paperformat.margin_right:
            command_args.extend(['--margin-right', str(paperformat.margin_right)])
        if paperformat.orientation:
            command_args.extend(['--orientation', str(paperformat.orientation)])
        if paperformat.header_line:
            command_args.extend(['--header-line'])

        return command_args

    def _merge_pdf(self, documents):
        """Merge PDF files into one.

        :param documents: list of pdf files
        :returns: string containing the merged pdf
        """
        writer = PdfFileWriter()
        for document in documents:
            reader = PdfFileReader(file(document.name, "rb"))
            for page in range(0, reader.getNumPages()):
                writer.addPage(reader.getPage(page))
            document.close()
        merged = cStringIO.StringIO()
        writer.write(merged)
        merged.seek(0)
        content = merged.read()
        merged.close()
        return content