# This file is part of beets.
# Copyright 2016, Adrian Sampson.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

"""Tests for template engine.
"""

import unittest

from beets.util import functemplate


def _normexpr(expr):
    """Normalize an Expression object's parts, collapsing multiple
    adjacent text blocks and removing empty text blocks. Generates a
    sequence of parts.
    """
    textbuf = []
    for part in expr.parts:
        if isinstance(part, str):
            textbuf.append(part)
        else:
            if textbuf:
                text = "".join(textbuf)
                if text:
                    yield text
                    textbuf = []
            yield part
    if textbuf:
        text = "".join(textbuf)
        if text:
            yield text


def _normparse(text):
    """Parse a template and then normalize the resulting Expression."""
    return _normexpr(functemplate._parse(text))


class ParseTest(unittest.TestCase):
    def test_empty_string(self):
        self.assertEqual(list(_normparse("")), [])

    def _assert_symbol(self, obj, ident):
        """Assert that an object is a Symbol with the given identifier."""
        assert isinstance(obj, functemplate.Symbol), "not a Symbol: %s" % repr(
            obj
        )
        self.assertEqual(
            obj.ident,
            ident,
            "wrong identifier: %s vs. %s" % (repr(obj.ident), repr(ident)),
        )

    def _assert_call(self, obj, ident, numargs):
        """Assert that an object is a Call with the given identifier and
        argument count.
        """
        assert isinstance(obj, functemplate.Call), "not a Call: %s" % repr(obj)
        self.assertEqual(
            obj.ident,
            ident,
            "wrong identifier: %s vs. %s" % (repr(obj.ident), repr(ident)),
        )
        self.assertEqual(
            len(obj.args),
            numargs,
            "wrong argument count in %s: %i vs. %i"
            % (repr(obj.ident), len(obj.args), numargs),
        )

    def test_plain_text(self):
        self.assertEqual(list(_normparse("hello world")), ["hello world"])

    def test_escaped_character_only(self):
        self.assertEqual(list(_normparse("$$")), ["$"])

    def test_escaped_character_in_text(self):
        self.assertEqual(list(_normparse("a $$ b")), ["a $ b"])

    def test_escaped_character_at_start(self):
        self.assertEqual(list(_normparse("$$ hello")), ["$ hello"])

    def test_escaped_character_at_end(self):
        self.assertEqual(list(_normparse("hello $$")), ["hello $"])

    def test_escaped_function_delim(self):
        self.assertEqual(list(_normparse("a $% b")), ["a % b"])

    def test_escaped_sep(self):
        self.assertEqual(list(_normparse("a $, b")), ["a , b"])

    def test_escaped_close_brace(self):
        self.assertEqual(list(_normparse("a $} b")), ["a } b"])

    def test_bare_value_delim_kept_intact(self):
        self.assertEqual(list(_normparse("a $ b")), ["a $ b"])

    def test_bare_function_delim_kept_intact(self):
        self.assertEqual(list(_normparse("a % b")), ["a % b"])

    def test_bare_opener_kept_intact(self):
        self.assertEqual(list(_normparse("a { b")), ["a { b"])

    def test_bare_closer_kept_intact(self):
        self.assertEqual(list(_normparse("a } b")), ["a } b"])

    def test_bare_sep_kept_intact(self):
        self.assertEqual(list(_normparse("a , b")), ["a , b"])

    def test_symbol_alone(self):
        parts = list(_normparse("$foo"))
        self.assertEqual(len(parts), 1)
        self._assert_symbol(parts[0], "foo")

    def test_symbol_in_text(self):
        parts = list(_normparse("hello $foo world"))
        self.assertEqual(len(parts), 3)
        self.assertEqual(parts[0], "hello ")
        self._assert_symbol(parts[1], "foo")
        self.assertEqual(parts[2], " world")

    def test_symbol_with_braces(self):
        parts = list(_normparse("hello${foo}world"))
        self.assertEqual(len(parts), 3)
        self.assertEqual(parts[0], "hello")
        self._assert_symbol(parts[1], "foo")
        self.assertEqual(parts[2], "world")

    def test_unclosed_braces_symbol(self):
        self.assertEqual(list(_normparse("a ${ b")), ["a ${ b"])

    def test_empty_braces_symbol(self):
        self.assertEqual(list(_normparse("a ${} b")), ["a ${} b"])

    def test_call_without_args_at_end(self):
        self.assertEqual(list(_normparse("foo %bar")), ["foo %bar"])

    def test_call_without_args(self):
        self.assertEqual(list(_normparse("foo %bar baz")), ["foo %bar baz"])

    def test_call_with_unclosed_args(self):
        self.assertEqual(list(_normparse("foo %bar{ baz")), ["foo %bar{ baz"])

    def test_call_with_unclosed_multiple_args(self):
        self.assertEqual(
            list(_normparse("foo %bar{bar,bar baz")), ["foo %bar{bar,bar baz"]
        )

    def test_call_empty_arg(self):
        parts = list(_normparse("%foo{}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 1)
        self.assertEqual(list(_normexpr(parts[0].args[0])), [])

    def test_call_single_arg(self):
        parts = list(_normparse("%foo{bar}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 1)
        self.assertEqual(list(_normexpr(parts[0].args[0])), ["bar"])

    def test_call_two_args(self):
        parts = list(_normparse("%foo{bar,baz}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 2)
        self.assertEqual(list(_normexpr(parts[0].args[0])), ["bar"])
        self.assertEqual(list(_normexpr(parts[0].args[1])), ["baz"])

    def test_call_with_escaped_sep(self):
        parts = list(_normparse("%foo{bar$,baz}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 1)
        self.assertEqual(list(_normexpr(parts[0].args[0])), ["bar,baz"])

    def test_call_with_escaped_close(self):
        parts = list(_normparse("%foo{bar$}baz}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 1)
        self.assertEqual(list(_normexpr(parts[0].args[0])), ["bar}baz"])

    def test_call_with_symbol_argument(self):
        parts = list(_normparse("%foo{$bar,baz}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 2)
        arg_parts = list(_normexpr(parts[0].args[0]))
        self.assertEqual(len(arg_parts), 1)
        self._assert_symbol(arg_parts[0], "bar")
        self.assertEqual(list(_normexpr(parts[0].args[1])), ["baz"])

    def test_call_with_nested_call_argument(self):
        parts = list(_normparse("%foo{%bar{},baz}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 2)
        arg_parts = list(_normexpr(parts[0].args[0]))
        self.assertEqual(len(arg_parts), 1)
        self._assert_call(arg_parts[0], "bar", 1)
        self.assertEqual(list(_normexpr(parts[0].args[1])), ["baz"])

    def test_nested_call_with_argument(self):
        parts = list(_normparse("%foo{%bar{baz}}"))
        self.assertEqual(len(parts), 1)
        self._assert_call(parts[0], "foo", 1)
        arg_parts = list(_normexpr(parts[0].args[0]))
        self.assertEqual(len(arg_parts), 1)
        self._assert_call(arg_parts[0], "bar", 1)
        self.assertEqual(list(_normexpr(arg_parts[0].args[0])), ["baz"])

    def test_sep_before_call_two_args(self):
        parts = list(_normparse("hello, %foo{bar,baz}"))
        self.assertEqual(len(parts), 2)
        self.assertEqual(parts[0], "hello, ")
        self._assert_call(parts[1], "foo", 2)
        self.assertEqual(list(_normexpr(parts[1].args[0])), ["bar"])
        self.assertEqual(list(_normexpr(parts[1].args[1])), ["baz"])

    def test_sep_with_symbols(self):
        parts = list(_normparse("hello,$foo,$bar"))
        self.assertEqual(len(parts), 4)
        self.assertEqual(parts[0], "hello,")
        self._assert_symbol(parts[1], "foo")
        self.assertEqual(parts[2], ",")
        self._assert_symbol(parts[3], "bar")

    def test_newline_at_end(self):
        parts = list(_normparse("foo\n"))
        self.assertEqual(len(parts), 1)
        self.assertEqual(parts[0], "foo\n")


class EvalTest(unittest.TestCase):
    def _eval(self, template):
        values = {
            "foo": "bar",
            "baz": "BaR",
        }
        functions = {
            "lower": str.lower,
            "len": len,
        }
        return functemplate.Template(template).substitute(values, functions)

    def test_plain_text(self):
        self.assertEqual(self._eval("foo"), "foo")

    def test_subtitute_value(self):
        self.assertEqual(self._eval("$foo"), "bar")

    def test_subtitute_value_in_text(self):
        self.assertEqual(self._eval("hello $foo world"), "hello bar world")

    def test_not_subtitute_undefined_value(self):
        self.assertEqual(self._eval("$bar"), "$bar")

    def test_function_call(self):
        self.assertEqual(self._eval("%lower{FOO}"), "foo")

    def test_function_call_with_text(self):
        self.assertEqual(self._eval("A %lower{FOO} B"), "A foo B")

    def test_nested_function_call(self):
        self.assertEqual(self._eval("%lower{%lower{FOO}}"), "foo")

    def test_symbol_in_argument(self):
        self.assertEqual(self._eval("%lower{$baz}"), "bar")

    def test_function_call_exception(self):
        res = self._eval("%lower{a,b,c,d,e}")
        assert isinstance(res, str)

    def test_function_returning_integer(self):
        self.assertEqual(self._eval("%len{foo}"), "3")

    def test_not_subtitute_undefined_func(self):
        self.assertEqual(self._eval("%bar{}"), "%bar{}")

    def test_not_subtitute_func_with_no_args(self):
        self.assertEqual(self._eval("%lower"), "%lower")

    def test_function_call_with_empty_arg(self):
        self.assertEqual(self._eval("%len{}"), "0")