#!/usr/bin/python3

"""
Delimited record importing functions.
"""

import csv
import builtins

def to_bool (v):
	try:
		return bool(int(v))
	except ValueError:
		if type(v) == str:
			return v.strip().lower().startswith("t")
		return False

transform = {
	"int": lambda v: builtins.int(float(v)),
	"float": float,
	"string": str,
	"bool": to_bool
}

def cast_values (row, fields):

	def enum_for (key):
		field = fields.get(key, {})
		def enum (val):
			if "enum" in field:
				ret_val = field.get("default", val)
				enums = field.get("enum", [])
				for enum_key in enums:
					if enum_key == val:
						ret_val = enums[enum_key]
						return ret_val
			return val
		return enum

	# Get rid of any unwanted data
	if None in row:
		del(row[None])

	for key in row:

		val = row[key]
		enum = enum_for(key)
		transformer = transform.get(fields.get(key, {}).get("type"), str)

		if type(val) == list:
			for i, v in enumerate(val):
				row[key][i] = transformer(enum(v))
		elif type(val) == dict:
			continue
		else:
			row[key] = transformer(enum(val))
	return row

def build_fieldnames (spec): #(arr, key, val):
	fieldnames = []

	if "fields" in spec:
		for key in spec["fields"]:
			index = spec["fields"][key]["column"]
			try:
				fieldnames[index] = key
			except IndexError:
				assert index >= 0
				fieldnames.extend(((index + 1) - len(fieldnames)) * [None])
				fieldnames[index] = key

	return fieldnames


def from_file_delimited (path, spec):

	fieldnames = build_fieldnames(spec)
	fields = spec.get("fields", [])
	delimiter = spec.get("delimiter", ",")
	firstRow = spec.get("firstRow", 0)
	headerRow = spec.get("headerRow", False)
	if headerRow:
		firstRow += 1

	records = []
	with open(path, "r", errors="ignore") as fd:

		if spec.get("type") == "x-sl+csv":
			fieldnames = None # Pick from header row
			firstRow = 0
			reader = csv.DictReader(fd, delimiter=delimiter)
		else:
			reader = csv.DictReader(fd, fieldnames=fieldnames, delimiter=delimiter)

		row = 0
		for line in reader:
			skip = False

			if row < firstRow:
				skip = True

			if not skip:
				records.append(cast_values(dict(line), fields))

			row += 1

	return records


def remap (line, headers):
	row = dict()
	for i, key in enumerate(headers):
		if "." in key[1:-1]:
			# This is an object
			k, attr = key.split(".")
			if not k in row:
				row[k] = dict()
			row[k][attr] = line[i]
		elif key in row:
			if type(row[key]) == list:
				row[key].append(line[i])
			else:
				row[key] = [ row[key], line[i] ]
		else:
			row[key] = line[i]
	return row

def from_file_saillines (path, spec):

	fields = {
		"sail_line": { "type": "int" },
		"source_line": { "type": "int" },
		"incr": { "type": "bool" },
		"ntba": { "type": "bool" }
	}

	# fields = spec.get("fields", sl_fields)
	delimiter = spec.get("delimiter", ",")
	firstRow = spec.get("firstRow", 0)

	records = []
	with open(path, "r", errors="ignore") as fd:
		row = 0
		reader = csv.reader(fd, delimiter=delimiter)
		while row < firstRow:
			next(reader)
			row += 1
		headers = [ h.strip() for h in next(reader) if len(h.strip()) ]

		for line in reader:
			records.append(cast_values(remap(line, headers), fields))

	return records


def from_file_p111 (path, spec):
	pass

def from_file (path, spec):
	if spec.get("type") == "x-sl+csv":
		return from_file_saillines(path, spec)
	else:
		return from_file_delimited(path, spec)