#!/usr/bin/python2.6
# coding: utf-8
import os
import sys
import time
import whoosh.index as index
import whoosh.writing as writing
import whoosh.fields as fields
from compat import str_format
import StringIO


def pdf_extract_metadata(filepath):
    from pdfminer.pdfparser import PDFParser, PDFDocument
    from pdfminer.pdfinterp import PDFPageInterpreter, PDFResourceManager
    from pdfminer.converter import TextConverter
    from pdfminer.layout import LAParams
    import lxml
    import lxml.etree

    outbuf = StringIO.StringIO()
    rsrcmgr = PDFResourceManager()
    device = TextConverter(rsrcmgr, outbuf, "utf-8", laparams=LAParams())
    parser = PDFParser(file(filepath, "rb"))
    doc = PDFDocument()

    parser.set_document(doc)
    doc.set_parser(parser)
    doc.initialize("")

    namespaces={
        "x":"adobe:ns:meta/",
        "dc":"http://purl.org/dc/elements/1.1/",
        "rdf":"http://www.w3.org/1999/02/22-rdf-syntax-ns#",
        "pdf":"http://ns.adobe.com/pdf/1.3/",
        "xap":"http://ns.adobe.com/xap/1.0/",
        "xmpMM":"http://ns.adobe.com/xap/1.0/mm/"}

    metadata = {}
    def add_metadata(tree, name, xpath_expr):
        d=tree.xpath(xpath_expr, namespaces=namespaces)
        if d:
            metadata[name] = "".join(d).strip()

    if doc.catalog.has_key("Metadata"):
        obj_ref = doc.catalog["Metadata"]
        obj_stream = obj_ref.resolve()
        if obj_stream.attrs['Subtype'].name == "XML":
            try:
                obj_data = obj_stream.get_data()[:-2] # XXX remove trailing chars
                print obj_data.strip()
                tree = lxml.etree.parse(StringIO.StringIO(obj_data))
                add_metadata(tree, "dc:title", "//rdf:Description/dc:title//*/text()")
                add_metadata(tree, "dc:creator", "//rdf:Description/dc:creator//*/text()")
                add_metadata(tree, "xap:CreateDate", "//rdf:Description/xap:CreateDate/text()")
                add_metadata(tree, "xap:CreaterTool", "//rdf:Description/xap:CreatorTool/text()")
                add_metadata(tree, "xap:ModifyDate", "//rdf:Description/xap:ModifyDate/text()")
                add_metadata(tree, "xap:CreateDate", "//rdf:Description/xap:CreateDate/text()")
                add_metadata(tree, "xap:MetadataDate", "//rdf:Description/xap:MetadataDate/text()")
                add_metadata(tree, "pdf:Producer", "//rdf:Description/pdf:Producer/text()")
                add_metadata(tree, "xmpMM:DocumentID", "//rdf:Description/xmpMM:DocumentID/text()")
                add_metadata(tree, "xmpMM:InstanceID", "//rdf:Description/xmpMM:InstanceID/text()")
            except lxml.etree.XMLSyntaxError,e:
                print e
    else:
        pass
    return metadata

def pdf_extract_text_pdfminer(filepath):
    from pdfminer.pdfparser import PDFParser, PDFDocument
    from pdfminer.pdfinterp import PDFPageInterpreter, PDFResourceManager
    from pdfminer.converter import TextConverter
    from pdfminer.layout import LAParams

    outbuf = StringIO.StringIO()
    rsrcmgr = PDFResourceManager()
    device = TextConverter(rsrcmgr, outbuf, "utf-8", laparams=LAParams())
    parser = PDFParser(file(filepath, "rb"))
    doc = PDFDocument()

    parser.set_document(doc)
    doc.set_parser(parser)
    doc.initialize("")

    interpreter = PDFPageInterpreter(rsrcmgr, device)
    for pagenumber, page in enumerate(doc.get_pages()):
        interpreter.process_page(page)
        outbuf.seek(0)
        content = unicode(outbuf.read(),"utf-8",errors="replace")
        yield (pagenumber+1, content) #start pages at 1
        outbuf.seek(0)

def pdf_extract_text_pypdf(filepath):
    import pyPdf
    inputfile = pyPdf.PdfFileReader(file(filepath, "r"))

    pagenumber = 1
    for page in inputfile.pages:
        content = page.extractText()
        yield (pagenumber, content)
        pagenumber += 1

""" Yields (pagenumber, text) """
def pdf_extract_text(filepath):
    try:
        return pdf_extract_text_pdfminer(filepath)
    except ImportError:
        print "Fallback to pypdf"
        return pdf_extract_text_pypdf(filepath)

schema_book = fields.Schema(
    pagenumber=fields.NUMERIC(stored=True),
    path=fields.ID(stored=True),
    content=fields.TEXT(stored=True),
    )

schema_metadata = fields.Schema(
    title = fields.TEXT(stored=True),
    path=fields.ID(stored=True,unique=True),
    createtime=fields.NUMERIC(stored=True) )

if not os.path.exists(u"index"):
    create_index = True
    os.mkdir(u"index")
    index_book = index.create_in(u"index", schema_book, u"book")
    index_metadata = index.create_in(u"index", schema_metadata, u"metadata")
else:
    create_index = False
    index_book = index.open_dir(u"index", u"book")
    index_metadata = index.open_dir(u"index", u"metadata")

filepaths = []
directory = unicode(sys.argv[1], "utf8")
searcher_book = index_book.searcher()
searcher_metadata = index_metadata.searcher()
print str_format(u"Walking {dir}",dir=directory)
filecount = 0
skipped = 0
for path, directories, files in os.walk(directory):
    for filename in files:
        if filename.endswith(u".pdf"):
            filepath = os.path.join(path, filename)
            if create_index or not searcher_metadata.document_number(path=filepath):
                filepaths.append(filepath)
                filecount += 1
            else:
                #skip files that are already indexed
                skipped += 1
            print str_format(u"\r{count} files found {skip} skipped", count=filecount+skipped, skip=skipped),
print ""

if not create_index: #update index for deleted files
    writer_book = index_book.writer()
    writer_metadata = index_metadata.writer()
    deleted = 0
    processed = 0
    for fields in searcher_metadata.all_stored_fields():
        path = fields["path"]
        processed += 1
        if not os.path.exists(path):
            writer_book.delete_by_term(u"path", path)
            writer_metadata.delete_by_term("path", path)
            deleted += 1
        print str_format(u"\r{proc} pages processed. {deleted} deleted", proc=processed, deleted=deleted),
    print ""
    writer_book.commit()
    writer_metadata.commit()

searcher_book.close()
searcher_metadata.close()

def process_file(filepath):
    try:
        print str_format(u"{pid} processing {filepath}", pid=os.getpid(), filepath=filepath)
        title = u"notimplemented"

        writer_metadata = index_metadata.writer()
        writer_metadata.add_document(title=title, path=filepath, createtime=time.time())
        writer_metadata.commit()
        writer_book = writing.BatchWriter(index_book, limit=1000)

        pagenumber = 1
        for pagenumber, content in pdf_extract_text(filepath):
            print str_format(u"{pid} processing {filepath} Page {page}", pid=os.getpid(), filepath=filepath, page=pagenumber)
            writer_book.add_document(pagenumber=pagenumber,
                                     path=filepath,
                                     content=content)
            pagenumber += 1

        print str_format(u"{pid} commit", pid=os.getpid())
        writer_book.commit()                         
    except KeyboardInterrupt:
        return "KeyboardInterrupt"
    except Exception,e:
        print str_format(u"{pid} failed at {filepath}: {err}", pid=os.getpid(), filepath=filepath, err=str(e))

try:
    import multiprocessing as mp
    pool = mp.Pool()
    jobs = []
    for filepath in filepaths:
        jobs.append( pool.apply_async( process_file, (filepath,) ) )
    pool.close()
    pool.join()
except KeyboardInterrupt:
    pool.terminate()
except ImportError:
    for filepath in filepaths:
        if process_file(filepath) == "KeyboardInterrupt":
            break

print u"optimize indexes"
index_metadata.optimize()
index_metadata.close()
index_book.optimize()
index_book.close()