# Copyright (c) 2021, Frappe Technologies Pvt. Ltd. and Contributors
# License: MIT. See LICENSE

import frappe
import os, base64, re, json
import hashlib
import mimetypes
import io
from frappe.utils import get_hook_method, get_files_path, random_string, encode, cstr, call_hook_method, cint
from frappe import _
from frappe import conf
from copy import copy
from urllib.parse import unquote
from frappe.utils.image import optimize_image

class MaxFileSizeReachedError(frappe.ValidationError):
	pass


def safe_b64decode(binary: bytes) -> bytes:
	"""Adds padding if doesn't already exist before decoding.

	This attempts to avoid the `binascii.Error: Incorrect padding` error raised
	when the number of trailing = is simply not enough :crie:. Although, it may
	be an indication of corrupted data.

	Refs:
		* https://en.wikipedia.org/wiki/Base64
		* https://stackoverflow.com/questions/2941995/python-ignore-incorrect-padding-error-when-base64-decoding
	"""
	return base64.b64decode(binary + b"===")


def get_file_url(file_data_name):
	data = frappe.db.get_value("File", file_data_name, ["file_name", "file_url"], as_dict=True)
	return data.file_url or data.file_name


def upload():
	# get record details
	dt = frappe.form_dict.doctype
	dn = frappe.form_dict.docname
	file_url = frappe.form_dict.file_url
	filename = frappe.form_dict.filename
	frappe.form_dict.is_private = cint(frappe.form_dict.is_private)

	if not filename and not file_url:
		frappe.msgprint(_("Please select a file or url"),
			raise_exception=True)

	file_doc = get_file_doc()

	comment = {}
	if dt and dn:
		comment = frappe.get_doc(dt, dn).add_comment("Attachment",
			_("added {0}").format("<a href='{file_url}' target='_blank'>{file_name}</a>{icon}".format(**{
				"icon": ' <i class="fa fa-lock text-warning"></i>' \
					if file_doc.is_private else "",
				"file_url": file_doc.file_url.replace("#", "%23") \
					if file_doc.file_name else file_doc.file_url,
				"file_name": file_doc.file_name or file_doc.file_url
			})))

	return {
		"name": file_doc.name,
		"file_name": file_doc.file_name,
		"file_url": file_doc.file_url,
		"is_private": file_doc.is_private,
		"comment": comment.as_dict() if comment else {}
	}

def get_file_doc(dt=None, dn=None, folder=None, is_private=None, df=None):
	'''returns File object (Document) from given parameters or form_dict'''
	r = frappe.form_dict

	if dt is None: dt = r.doctype
	if dn is None: dn = r.docname
	if df is None: df = r.docfield
	if folder is None: folder = r.folder
	if is_private is None: is_private = r.is_private

	if r.filedata:
		file_doc = save_uploaded(dt, dn, folder, is_private, df)

	elif r.file_url:
		file_doc = save_url(r.file_url, r.filename, dt, dn, folder, is_private, df)

	return file_doc

def save_uploaded(dt, dn, folder, is_private, df=None):
	fname, content = get_uploaded_content()
	if content:
		return save_file(fname, content, dt, dn, folder, is_private=is_private, df=df)
	else:
		raise Exception

def save_url(file_url, filename, dt, dn, folder, is_private, df=None):
	# if not (file_url.startswith("http://") or file_url.startswith("https://")):
	# 	frappe.msgprint("URL must start with 'http://' or 'https://'")
	# 	return None, None

	file_url = unquote(file_url)
	file_size = frappe.form_dict.file_size

	f = frappe.get_doc({
		"doctype": "File",
		"file_url": file_url,
		"file_name": filename,
		"attached_to_doctype": dt,
		"attached_to_name": dn,
		"attached_to_field": df,
		"folder": folder,
		"file_size": file_size,
		"is_private": is_private
	})
	f.flags.ignore_permissions = True
	try:
		f.insert()
	except frappe.DuplicateEntryError:
		return frappe.get_doc("File", f.duplicate_entry)
	return f


def get_uploaded_content():
	# should not be unicode when reading a file, hence using frappe.form
	if 'filedata' in frappe.form_dict:
		if "," in frappe.form_dict.filedata:
			frappe.form_dict.filedata = frappe.form_dict.filedata.rsplit(",", 1)[1]
		frappe.uploaded_content = safe_b64decode(frappe.form_dict.filedata)
		frappe.uploaded_filename = frappe.form_dict.filename
		return frappe.uploaded_filename, frappe.uploaded_content
	else:
		frappe.msgprint(_('No file attached'))
		return None, None

def save_file(fname, content, dt, dn, folder=None, decode=False, is_private=0, df=None):
	if decode:
		if isinstance(content, str):
			content = content.encode("utf-8")

		if b"," in content:
			content = content.split(b",")[1]
		content = safe_b64decode(content)

	file_size = check_max_file_size(content)
	content_hash = get_content_hash(content)
	content_type = mimetypes.guess_type(fname)[0]
	fname = get_file_name(fname, content_hash[-6:])
	file_data = get_file_data_from_hash(content_hash, is_private=is_private)
	if not file_data:
		call_hook_method("before_write_file", file_size=file_size)

		write_file_method = get_hook_method('write_file', fallback=save_file_on_filesystem)
		file_data = write_file_method(fname, content, content_type=content_type, is_private=is_private)
		file_data = copy(file_data)

	file_data.update({
		"doctype": "File",
		"attached_to_doctype": dt,
		"attached_to_name": dn,
		"attached_to_field": df,
		"folder": folder,
		"file_size": file_size,
		"content_hash": content_hash,
		"is_private": is_private
	})

	f = frappe.get_doc(file_data)
	f.flags.ignore_permissions = True
	try:
		f.insert()
	except frappe.DuplicateEntryError:
		return frappe.get_doc("File", f.duplicate_entry)

	return f


def get_file_data_from_hash(content_hash, is_private=0):
	for name in frappe.db.sql_list("select name from `tabFile` where content_hash=%s and is_private=%s", (content_hash, is_private)):
		b = frappe.get_doc('File', name)
		return {k: b.get(k) for k in frappe.get_hooks()['write_file_keys']}
	return False


def save_file_on_filesystem(fname, content, content_type=None, is_private=0):
	fpath = write_file(content, fname, is_private)

	if is_private:
		file_url = "/private/files/{0}".format(fname)
	else:
		file_url = "/files/{0}".format(fname)

	return {
		'file_name': os.path.basename(fpath),
		'file_url': file_url
	}


def get_max_file_size():
	return conf.get('max_file_size') or 10485760


def check_max_file_size(content):
	max_file_size = get_max_file_size()
	file_size = len(content)

	if file_size > max_file_size:
		frappe.msgprint(_("File size exceeded the maximum allowed size of {0} MB").format(
			max_file_size / 1048576),
			raise_exception=MaxFileSizeReachedError)

	return file_size


def write_file(content, fname, is_private=0):
	"""write file to disk with a random name (to compare)"""
	file_path = get_files_path(is_private=is_private)

	# create directory (if not exists)
	frappe.create_folder(file_path)
	# write the file
	if isinstance(content, str):
		content = content.encode()
	with open(os.path.join(file_path.encode('utf-8'), fname.encode('utf-8')), 'wb+') as f:
		f.write(content)

	return get_files_path(fname, is_private=is_private)


def remove_all(dt, dn, from_delete=False, delete_permanently=False):
	"""remove all files in a transaction"""
	try:
		for fid in frappe.db.sql_list("""select name from `tabFile` where
			attached_to_doctype=%s and attached_to_name=%s""", (dt, dn)):
			if from_delete:
				# If deleting a doc, directly delete files
				frappe.delete_doc("File", fid, ignore_permissions=True, delete_permanently=delete_permanently)
			else:
				# Removes file and adds a comment in the document it is attached to
				remove_file(fid=fid, attached_to_doctype=dt, attached_to_name=dn,
					from_delete=from_delete, delete_permanently=delete_permanently)
	except Exception as e:
		if e.args[0]!=1054: raise # (temp till for patched)

def remove_file(fid=None, attached_to_doctype=None, attached_to_name=None, from_delete=False, delete_permanently=False):
	"""Remove file and File entry"""
	file_name = None
	if not (attached_to_doctype and attached_to_name):
		attached = frappe.db.get_value("File", fid,
			["attached_to_doctype", "attached_to_name", "file_name"])
		if attached:
			attached_to_doctype, attached_to_name, file_name = attached

	ignore_permissions, comment = False, None
	if attached_to_doctype and attached_to_name and not from_delete:
		doc = frappe.get_doc(attached_to_doctype, attached_to_name)
		ignore_permissions = doc.has_permission("write") or False
		if frappe.flags.in_web_form:
			ignore_permissions = True
		if not file_name:
			file_name = frappe.db.get_value("File", fid, "file_name")
		comment = doc.add_comment("Attachment Removed", _("Removed {0}").format(file_name))
		frappe.delete_doc("File", fid, ignore_permissions=ignore_permissions, delete_permanently=delete_permanently)

	return comment


def delete_file_data_content(doc, only_thumbnail=False):
	method = get_hook_method('delete_file_data_content', fallback=delete_file_from_filesystem)
	method(doc, only_thumbnail=only_thumbnail)


def delete_file_from_filesystem(doc, only_thumbnail=False):
	"""Delete file, thumbnail from File document"""
	if only_thumbnail:
		delete_file(doc.thumbnail_url)
	else:
		delete_file(doc.file_url)
		delete_file(doc.thumbnail_url)


def delete_file(path):
	"""Delete file from `public folder`"""
	if path:
		if ".." in path.split("/"):
			frappe.msgprint(_("It is risky to delete this file: {0}. Please contact your System Manager.").format(path))

		parts = os.path.split(path.strip("/"))
		if parts[0]=="files":
			path = frappe.utils.get_site_path("public", "files", parts[-1])

		else:
			path = frappe.utils.get_site_path("private", "files", parts[-1])

		path = encode(path)
		if os.path.exists(path):
			os.remove(path)


def get_file(fname):
	"""Returns [`file_name`, `content`] for given file name `fname`"""
	file_path = get_file_path(fname)

	# read the file
	with io.open(encode(file_path), mode='rb') as f:
		content = f.read()
		try:
			# for plain text files
			content = content.decode()
		except UnicodeDecodeError:
			# for .png, .jpg, etc
			pass

	return [file_path.rsplit("/", 1)[-1], content]


def get_file_path(file_name):
	"""Returns file path from given file name"""
	if '../' in file_name:
		return

	f = frappe.db.sql("""select file_url from `tabFile`
		where name=%s or file_name=%s""", (file_name, file_name))
	if f:
		file_name = f[0][0]

	file_path = file_name

	if "/" not in file_path:
		file_path = "/files/" + file_path

	if file_path.startswith("/private/files/"):
		file_path = get_files_path(*file_path.split("/private/files/", 1)[1].split("/"), is_private=1)

	elif file_path.startswith("/files/"):
		file_path = get_files_path(*file_path.split("/files/", 1)[1].split("/"))

	else:
		frappe.throw(_("There is some problem with the file url: {0}").format(file_path))

	return file_path


def get_content_hash(content):
	if isinstance(content, str):
		content = content.encode()
	return hashlib.md5(content).hexdigest()


def get_file_name(fname, optional_suffix):
	# convert to unicode
	fname = cstr(fname)

	n_records = frappe.db.sql("select name from `tabFile` where file_name=%s", fname)
	if len(n_records) > 0 or os.path.exists(encode(get_files_path(fname))):
		f = fname.rsplit('.', 1)
		if len(f) == 1:
			partial, extn = f[0], ""
		else:
			partial, extn = f[0], "." + f[1]
		return '{partial}{suffix}{extn}'.format(partial=partial, extn=extn, suffix=optional_suffix)
	return fname


@frappe.whitelist()
def download_file(file_url):
	"""
	Download file using token and REST API. Valid session or
	token is required to download private files.

	Method : GET
	Endpoint : frappe.utils.file_manager.download_file
	URL Params : file_name = /path/to/file relative to site path
	"""
	file_doc = frappe.get_doc("File", {"file_url":file_url})
	file_doc.check_permission("read")
	path = os.path.join(get_files_path(), os.path.basename(file_url))

	with open(path, "rb") as fileobj:
		filedata = fileobj.read()
	frappe.local.response.filename = os.path.basename(file_url)
	frappe.local.response.filecontent = filedata
	frappe.local.response.type = "download"

@frappe.whitelist()
def add_attachments(doctype, name, attachments):
	'''Add attachments to the given DocType'''
	if isinstance(attachments, str):
		attachments = json.loads(attachments)
	# loop through attachments
	files =[]
	for a in attachments:
		if isinstance(a, str):
			attach = frappe.db.get_value("File", {"name":a}, ["file_name", "file_url", "is_private"], as_dict=1)
			# save attachments to new doc
			f = save_url(attach.file_url, attach.file_name, doctype, name, "Home/Attachments", attach.is_private)
			files.append(f)

	return files