package db_test

import (
	"bytes"
	"encoding/gob"
	"os"
	"path/filepath"
	"reflect"
	"testing"

	"codeflow.dananglin.me.uk/apollo/pelican/internal/board"
	"codeflow.dananglin.me.uk/apollo/pelican/internal/db"
	bolt "go.etcd.io/bbolt"
)

func TestWriteAndReadStatusList(t *testing.T) {
	t.Parallel()

	var database *bolt.DB

	var err error

	projectDir, err := projectRoot()
	if err != nil {
		t.Fatalf(err.Error())
	}

	testDB := filepath.Join(projectDir, "test", "databases", "Database_TestWriteAndReadStatusList.db")
	os.Remove(testDB)

	if database, err = db.OpenDatabase(testDB); err != nil {
		t.Fatalf("An error occurred whilst opening the test database %s, %s.", testDB, err)
	}

	defer func() {
		_ = database.Close()
	}()

	testWriteStatusList(t, database)
	testReadStatusList(t, database)
}

func testWriteStatusList(t *testing.T, database *bolt.DB) {
	t.Helper()

	newStatusList := []board.Status{
		{
			ID:       -1,
			Name:     "Backlog",
			CardIds:  []int{1, 14, 9, 10},
			Position: 1,
		},
		{
			ID:       -1,
			Name:     "Next",
			CardIds:  []int{2, 5, 12},
			Position: 2,
		},
		{
			ID:       -1,
			Name:     "In progress",
			CardIds:  []int{3, 14},
			Position: 3,
		},
		{
			ID:       -1,
			Name:     "Finished!",
			CardIds:  []int{4, 6, 7, 8, 11, 13},
			Position: 4,
		},
	}

	boltItems := make([]db.BoltItem, len(newStatusList))

	for i := range newStatusList {
		boltItems[i] = &newStatusList[i]
	}

	if _, err := db.WriteMany(database, db.StatusBucket, boltItems); err != nil {
		t.Fatalf("An error occurred whilst writing the initial status list to the database, %s", err)
	}
}

func testReadStatusList(t *testing.T, database *bolt.DB) {
	t.Helper()

	data, err := db.ReadAll(database, db.StatusBucket)
	if err != nil {
		t.Fatalf("An error occurred whilst reading the modified status list from the database, %s", err)
	}

	got := make([]board.Status, len(data))

	for ind, d := range data {
		buf := bytes.NewBuffer(d)

		decoder := gob.NewDecoder(buf)

		var status board.Status

		if err := decoder.Decode(&status); err != nil {
			t.Fatalf("An error occurred whilst decoding data, %s", err)
		}

		got[ind] = status
	}

	want := []board.Status{
		{
			ID:       1,
			Name:     "Backlog",
			CardIds:  []int{1, 14, 9, 10},
			Position: 1,
		},
		{
			ID:       2,
			Name:     "Next",
			CardIds:  []int{2, 5, 12},
			Position: 2,
		},
		{
			ID:       3,
			Name:     "In progress",
			CardIds:  []int{3, 14},
			Position: 3,
		},
		{
			ID:       4,
			Name:     "Finished!",
			CardIds:  []int{4, 6, 7, 8, 11, 13},
			Position: 4,
		},
	}

	if !reflect.DeepEqual(got, want) {
		t.Errorf("Unexpected status list read from the database: got %+v, want %+v", got, want)
	} else {
		t.Logf("Expected status list read from the database: got %+v", got)
	}
}

func TestReadAndWriteCards(t *testing.T) {
	t.Parallel()

	var database *bolt.DB

	var err error

	projectDir, err := projectRoot()
	if err != nil {
		t.Fatalf(err.Error())
	}

	testDB := filepath.Join(projectDir, "test", "databases", "Database_TestReadWriteCard.db")
	os.Remove(testDB)

	if database, err = db.OpenDatabase(testDB); err != nil {
		t.Fatalf("An error occurred whilst opening the test database %s, %s.", testDB, err)
	}

	defer func() {
		_ = database.Close()
	}()

	singleCard := board.Card{
		ID:          -1,
		Title:       "A test task.",
		Description: "This task should be completed.",
	}

	singleCardID := testWriteOneCard(t, database, singleCard)
	testReadOneCard(t, database, singleCardID)

	manyCards := []board.Card{
		{
			ID:          -1,
			Title:       "Test card A.",
			Description: "This is test card A.",
		},
		{
			ID:          -1,
			Title:       "Test card B.",
			Description: "This is test card B.",
		},
		{
			ID:          -1,
			Title:       "Test card C.",
			Description: "This is test card C.",
		},
	}

	manyCardIDs := testWriteManyCard(t, database, manyCards)
	testReadManyCards(t, database, manyCardIDs)
}

func testWriteOneCard(t *testing.T, database *bolt.DB, card board.Card) int {
	t.Helper()

	cardID, err := db.Write(database, db.CardBucket, &card)
	if err != nil {
		t.Fatalf("An error occurred whilst writing the card to the database, %s", err)
	}

	return cardID
}

func testReadOneCard(t *testing.T, database *bolt.DB, cardID int) {
	t.Helper()

	data, err := db.Read(database, db.CardBucket, cardID)
	if err != nil {
		t.Fatalf("An error occurred whilst loading the modified from the database, %s", err)
	}

	var got board.Card

	buf := bytes.NewBuffer(data)

	decoder := gob.NewDecoder(buf)

	if err := decoder.Decode(&got); err != nil {
		t.Fatalf("Unable to decode data, %s", err)
	}

	want := board.Card{
		ID:          1,
		Title:       "A test task.",
		Description: "This task should be completed.",
	}

	if !reflect.DeepEqual(got, want) {
		t.Errorf("Unexpected card read from the database: got %+v, want %+v", got, want)
	} else {
		t.Logf("Expected card read from the database: got %+v", got)
	}
}

func testWriteManyCard(t *testing.T, database *bolt.DB, cards []board.Card) []int {
	t.Helper()

	boltItems := make([]db.BoltItem, len(cards))

	for i := range cards {
		boltItems[i] = &cards[i]
	}

	ids, err := db.WriteMany(database, db.CardBucket, boltItems)
	if err != nil {
		t.Fatalf("An error occurred whilst writing many cards to the database, %s", err)
	}

	return ids
}

func testReadManyCards(t *testing.T, database *bolt.DB, cardIDs []int) {
	t.Helper()

	data, err := db.ReadMany(database, db.CardBucket, cardIDs)
	if err != nil {
		t.Fatalf("An error occurred whilst reading the data from the database, %s", err)
	}

	got := make([]board.Card, len(data))

	for i, d := range data {
		buf := bytes.NewBuffer(d)

		decoder := gob.NewDecoder(buf)

		var c board.Card

		if err := decoder.Decode(&c); err != nil {
			t.Fatalf("An error occurred whilst decoding data, %s", err)
		}

		got[i] = c
	}

	want := []board.Card{
		{
			ID:          2,
			Title:       "Test card A.",
			Description: "This is test card A.",
		},
		{
			ID:          3,
			Title:       "Test card B.",
			Description: "This is test card B.",
		},
		{
			ID:          4,
			Title:       "Test card C.",
			Description: "This is test card C.",
		},
	}

	if !reflect.DeepEqual(got, want) {
		t.Errorf("Unexpected list of cards read from the database: got %+v, want %+v", got, want)
	} else {
		t.Logf("Expected list of cards read from the database: got %+v", got)
	}
}

func TestDeleteOneCard(t *testing.T) {
	t.Parallel()

	var database *bolt.DB

	var err error

	projectDir, err := projectRoot()
	if err != nil {
		t.Fatalf(err.Error())
	}

	testDB := filepath.Join(projectDir, "test", "databases", "Database_TestDeleteOneCard.db")
	os.Remove(testDB)

	if database, err = db.OpenDatabase(testDB); err != nil {
		t.Fatalf("An error occurred whilst opening the test database %s, %s.", testDB, err)
	}

	defer func() {
		_ = database.Close()
	}()

	// Create one card, get card ID.
	card := board.Card{
		ID:          -1,
		Title:       "Test card",
		Description: "",
	}

	cardID, err := db.Write(database, db.CardBucket, &card)
	if err != nil {
		t.Fatalf("ERROR: Unable to create the card in the database, %v", err)
	}

	cards, err := db.ReadAll(database, db.CardBucket)
	if err != nil {
		t.Fatalf("ERROR: Unable to read the cards from the database, %v", err)
	}

	numCards := len(cards)
	if numCards != 1 {
		t.Fatalf("ERROR: Unexpected number of cards returned from the card bucket; want 1; got %d", numCards)
	}

	if err := db.Delete(database, db.CardBucket, cardID); err != nil {
		t.Fatalf("ERROR: Unable to delete the card from the database, %v", err)
	}

	// Get all cards, expect length = 0; error if not 0
	cards, err = db.ReadAll(database, db.CardBucket)
	if err != nil {
		t.Fatalf("ERROR: Unable to read the cards from the database, %v", err)
	}

	numCards = len(cards)
	if numCards != 0 {
		t.Errorf("%s\tUnexpected number of cards returned from the card bucket; want 0; got %d", failure, numCards)
	} else {
		t.Logf("%s\tThe card was successfully deleted from the database.", success)
	}
}