package keys

import (
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	cmn "github.com/tendermint/tmlibs/common"
)

func TestLengthCalc(t *testing.T) {
	assert := assert.New(t)

	cases := []struct {
		bytes, words int
		flexible     bool
	}{
		{1, 1, false},
		{2, 2, false},
		// bytes pairs with same word count
		{3, 3, true},
		{4, 3, true},
		{5, 4, false},
		// bytes pairs with same word count
		{10, 8, true},
		{11, 8, true},
		{12, 9, false},
		{13, 10, false},
		{20, 15, false},
		// bytes pairs with same word count
		{21, 16, true},
		{32, 24, true},
	}

	for _, tc := range cases {
		wl := wordlenFromBytes(tc.bytes)
		assert.Equal(tc.words, wl, "%d", tc.bytes)

		bl, flex := bytelenFromWords(tc.words)
		assert.Equal(tc.flexible, flex, "%d", tc.words)
		if !flex {
			assert.Equal(tc.bytes, bl, "%d", tc.words)
		} else {
			// check if it is either tc.bytes or tc.bytes +1
			choices := []int{tc.bytes, tc.bytes + 1}
			assert.Contains(choices, bl, "%d", tc.words)
		}
	}
}

func TestEncodeDecode(t *testing.T) {
	assert, require := assert.New(t), require.New(t)

	codec, err := LoadCodec("english")
	require.Nil(err, "%+v", err)

	cases := [][]byte{
		{7, 8, 9},                         // TODO: 3 words -> 3 or 4 bytes
		{12, 54, 99, 11},                  // TODO: 3 words -> 3 or 4 bytes
		{0, 54, 99, 11},                   // TODO: 3 words -> 3 or 4 bytes, detect leading 0
		{1, 2, 3, 4, 5},                   // normal
		{0, 0, 0, 0, 122, 23, 82, 195},    // leading 0s (8 chars, unclear)
		{0, 0, 0, 0, 5, 22, 123, 55, 22},  // leading 0s (9 chars, clear)
		{22, 44, 55, 1, 13, 0, 0, 0, 0},   // trailing 0s (9 chars, clear)
		{0, 5, 253, 2, 0},                 // leading and trailing zeros
		{255, 196, 172, 234, 192, 255},    // big numbers
		{255, 196, 172, 1, 234, 192, 255}, // big numbers, two length choices
		// others?
	}

	for i, tc := range cases {
		w, err := codec.BytesToWords(tc)
		if assert.Nil(err, "%d: %v", i, err) {
			b, err := codec.WordsToBytes(w)
			if assert.Nil(err, "%d: %v", i, err) {
				assert.Equal(len(tc), len(b))
				assert.Equal(tc, b)
			}
		}
	}
}

func TestCheckInvalidLists(t *testing.T) {
	assert := assert.New(t)

	trivial := []string{"abc", "def"}
	short := make([]string, 1234)
	long := make([]string, BankSize+1)
	right := make([]string, BankSize)
	dups := make([]string, BankSize)

	for _, list := range [][]string{short, long, right, dups} {
		for i := range list {
			list[i] = cmn.RandStr(8)
		}
	}
	// create one single duplicate
	dups[192] = dups[782]

	cases := []struct {
		words    []string
		loadable bool
		valid    bool
	}{
		{trivial, false, false},
		{short, false, false},
		{long, false, false},
		{dups, true, false}, // we only check dups on first use...
		{right, true, true},
	}

	for i, tc := range cases {
		codec, err := NewCodec(tc.words)
		if !tc.loadable {
			assert.NotNil(err, "%d", i)
		} else if assert.Nil(err, "%d: %+v", i, err) {
			data := cmn.RandBytes(32)
			w, err := codec.BytesToWords(data)
			if tc.valid {
				assert.Nil(err, "%d: %+v", i, err)
				b, err := codec.WordsToBytes(w)
				assert.Nil(err, "%d: %+v", i, err)
				assert.Equal(data, b)
			} else {
				assert.NotNil(err, "%d", i)
			}
		}
	}

}

func getRandWord(c *WordCodec) string {
	idx := cmn.RandInt() % BankSize
	return c.words[idx]
}

func getDiffWord(c *WordCodec, not string) string {
	w := getRandWord(c)
	if w == not {
		w = getRandWord(c)
	}
	return w
}

func TestCheckTypoDetection(t *testing.T) {
	assert, require := assert.New(t), require.New(t)

	banks := []string{"english", "spanish", "japanese", "chinese_simplified"}

	for _, bank := range banks {
		codec, err := LoadCodec(bank)
		require.Nil(err, "%s: %+v", bank, err)
		for i := 0; i < 1000; i++ {
			numBytes := cmn.RandInt()%60 + 4
			data := cmn.RandBytes(numBytes)

			words, err := codec.BytesToWords(data)
			assert.Nil(err, "%s: %+v", bank, err)
			good, err := codec.WordsToBytes(words)
			assert.Nil(err, "%s: %+v", bank, err)
			assert.Equal(data, good, bank)

			// now try some tweaks...
			cut := words[1:]
			_, err = codec.WordsToBytes(cut)
			assert.NotNil(err, "%s: %s", bank, words)

			// swap a word within the bank, should fails
			words[3] = getDiffWord(codec, words[3])
			_, err = codec.WordsToBytes(words)
			assert.NotNil(err, "%s: %s", bank, words)

			// put a random word here, must fail
			words[3] = cmn.RandStr(10)
			_, err = codec.WordsToBytes(words)
			assert.NotNil(err, "%s: %s", bank, words)
		}
	}
}