// Copyright 2021 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package charset_test

import (
	"fmt"
	"testing"
	"unicode/utf8"

	"github.com/pingcap/tidb/parser/charset"
	"github.com/stretchr/testify/require"
	"golang.org/x/text/transform"
)

func TestEncoding(t *testing.T) {
	t.Parallel()
	enc := charset.NewEncoding(charset.CharsetGBK)
	require.Equal(t, charset.CharsetGBK, enc.Name())

	txt := []byte("一二三四")
	e, _ := charset.Lookup("gbk")
	gbkEncodedTxt, _, err := transform.Bytes(e.NewEncoder(), txt)
	require.NoError(t, err)
	result, err := enc.Decode(nil, gbkEncodedTxt)
	require.NoError(t, err)
	require.Equal(t, txt, result)

	gbkEncodedTxt2, err := enc.Encode(nil, txt)
	require.NoError(t, err)
	require.Equal(t, gbkEncodedTxt2, gbkEncodedTxt)
	result, err = enc.Decode(nil, gbkEncodedTxt2)
	require.NoError(t, err)
	require.Equal(t, txt, result)

	GBKCases := []struct {
		utf8Str string
		result  string
		isValid bool
	}{
		{"一二三", "涓?簩涓?", false}, // MySQL reports '涓?簩涓'.
		{"一二三123", "涓?簩涓?23", false},
		{"案1案2", "妗?妗?", false},
		{"焊䏷菡釬", "鐒婁彿鑿￠嚞", true},
		{"鞍杏以伊位依", "闉嶆潖浠ヤ紛浣嶄緷", true},
		{"移維緯胃萎衣謂違", "绉荤董绶?儍钀庤。璎傞仌", false},
		{"仆仂仗仞仭仟价伉佚估", "浠嗕粋浠椾粸浠?粺浠蜂級浣氫及", false},
		{"佝佗佇佶侈侏侘佻佩佰侑佯", "浣濅綏浣囦蕉渚堜緩渚樹交浣╀桨渚戜蒋", true},
	}
	for _, tc := range GBKCases {
		cmt := fmt.Sprintf("%v", tc)
		result, err = enc.Decode(nil, []byte(tc.utf8Str))
		if tc.isValid {
			require.NoError(t, err, cmt)
		} else {
			require.Error(t, err, cmt)
		}
		require.Equal(t, tc.result, string(result), cmt)
	}

	utf8Cases := []struct {
		utf8Str string
		result  string
		isValid bool
	}{
		{"一二三", "һ\xb6\xfe\xc8\xfd", true},
		{"🀁", "?", false},
		{"valid_string_🀁", "valid_string_?", false},
	}
	for _, tc := range utf8Cases {
		cmt := fmt.Sprintf("%v", tc)
		result, err = enc.Encode(nil, []byte(tc.utf8Str))
		if tc.isValid {
			require.NoError(t, err, cmt)
		} else {
			require.Error(t, err, cmt)
		}
		require.Equal(t, tc.result, string(result), cmt)
	}
}

func TestStringValidatorASCII(t *testing.T) {
	v := charset.StringValidatorASCII{}
	testCases := []struct {
		str        string
		strategy   charset.TruncateStrategy
		expected   string
		invalidPos int
	}{
		{"", charset.TruncateStrategyEmpty, "", -1},
		{"qwerty", charset.TruncateStrategyEmpty, "qwerty", -1},
		{"qwÊrty", charset.TruncateStrategyEmpty, "", 2},
		{"qwÊrty", charset.TruncateStrategyTrim, "qw", 2},
		{"qwÊrty", charset.TruncateStrategyReplace, "qw?rty", 2},
		{"中文", charset.TruncateStrategyEmpty, "", 0},
		{"中文?qwert", charset.TruncateStrategyTrim, "", 0},
		{"中文?qwert", charset.TruncateStrategyReplace, "???qwert", 0},
	}
	for _, tc := range testCases {
		msg := fmt.Sprintf("%v", tc)
		actual, invalidPos := v.Truncate(tc.str, tc.strategy)
		require.Equal(t, tc.expected, actual, msg)
		require.Equal(t, tc.invalidPos, invalidPos, msg)
	}
	require.Equal(t, -1, v.Validate("qwerty"))
	require.Equal(t, 2, v.Validate("qwÊrty"))
	require.Equal(t, 0, v.Validate("中文"))
}

func TestStringValidatorUTF8(t *testing.T) {
	// Test charset "utf8mb4".
	v := charset.StringValidatorUTF8{IsUTF8MB4: true}
	oxfffefd := string([]byte{0xff, 0xfe, 0xfd})
	testCases := []struct {
		str        string
		strategy   charset.TruncateStrategy
		expected   string
		invalidPos int
	}{
		{"", charset.TruncateStrategyEmpty, "", -1},
		{"qwerty", charset.TruncateStrategyEmpty, "qwerty", -1},
		{"qwÊrty", charset.TruncateStrategyEmpty, "qwÊrty", -1},
		{"qwÊ合法字符串", charset.TruncateStrategyEmpty, "qwÊ合法字符串", -1},
		{"😂", charset.TruncateStrategyEmpty, "😂", -1},
		{oxfffefd, charset.TruncateStrategyEmpty, "", 0},
		{oxfffefd, charset.TruncateStrategyReplace, "???", 0},
		{"中文" + oxfffefd, charset.TruncateStrategyTrim, "中文", 6},
		{"中文" + oxfffefd, charset.TruncateStrategyReplace, "中文???", 6},
		{string(utf8.RuneError), charset.TruncateStrategyEmpty, "�", -1},
	}
	for _, tc := range testCases {
		msg := fmt.Sprintf("%v", tc)
		actual, invalidPos := v.Truncate(tc.str, tc.strategy)
		require.Equal(t, tc.expected, actual, msg)
		require.Equal(t, tc.invalidPos, invalidPos, msg)
	}
	// Test charset "utf8" with checking mb4 value.
	v = charset.StringValidatorUTF8{IsUTF8MB4: false, CheckMB4ValueInUTF8: true}
	testCases = []struct {
		str        string
		strategy   charset.TruncateStrategy
		expected   string
		invalidPos int
	}{
		{"", charset.TruncateStrategyEmpty, "", -1},
		{"qwerty", charset.TruncateStrategyEmpty, "qwerty", -1},
		{"qwÊrty", charset.TruncateStrategyEmpty, "qwÊrty", -1},
		{"qwÊ合法字符串", charset.TruncateStrategyEmpty, "qwÊ合法字符串", -1},
		{"😂", charset.TruncateStrategyEmpty, "", 0},
		{"😂", charset.TruncateStrategyReplace, "?", 0},
		{"valid_str😂", charset.TruncateStrategyReplace, "valid_str?", 9},
		{oxfffefd, charset.TruncateStrategyEmpty, "", 0},
		{oxfffefd, charset.TruncateStrategyReplace, "???", 0},
		{"中文" + oxfffefd, charset.TruncateStrategyTrim, "中文", 6},
		{"中文" + oxfffefd, charset.TruncateStrategyReplace, "中文???", 6},
		{string(utf8.RuneError), charset.TruncateStrategyEmpty, "�", -1},
	}
	for _, tc := range testCases {
		msg := fmt.Sprintf("%v", tc)
		actual, invalidPos := v.Truncate(tc.str, tc.strategy)
		require.Equal(t, tc.expected, actual, msg)
		require.Equal(t, tc.invalidPos, invalidPos, msg)
	}
}

func TestStringValidatorGBK(t *testing.T) {
	v := charset.StringValidatorOther{Charset: "gbk"}
	testCases := []struct {
		str        string
		strategy   charset.TruncateStrategy
		expected   string
		invalidPos int
	}{
		{"", charset.TruncateStrategyEmpty, "", -1},
		{"asdf", charset.TruncateStrategyEmpty, "asdf", -1},
		{"中文", charset.TruncateStrategyEmpty, "中文", -1},
		{"À", charset.TruncateStrategyEmpty, "", 0},
		{"À", charset.TruncateStrategyReplace, "?", 0},
		{"中文À中文", charset.TruncateStrategyTrim, "中文", 6},
		{"中文À中文", charset.TruncateStrategyReplace, "中文?中文", 6},
		{"asdfÀ", charset.TruncateStrategyReplace, "asdf?", 4},
	}
	for _, tc := range testCases {
		msg := fmt.Sprintf("%v", tc)
		actual, invalidPos := v.Truncate(tc.str, tc.strategy)
		require.Equal(t, tc.expected, actual, msg)
		require.Equal(t, tc.invalidPos, invalidPos, msg)
	}
}