package test

import (
	domainArticle "RenewCMS/internal/domain/article"
	domainInvite "RenewCMS/internal/domain/invite"
	"RenewCMS/internal/infrastructure/persistence/database"
	"RenewCMS/internal/infrastructure/persistence/models"
	"database/sql"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	mysqldriver "github.com/go-sql-driver/mysql"
	"gorm.io/gorm"
)

func migratedMySQL(t *testing.T) (*mysqlTestServer, database.MySQLConfig, *gorm.DB) {
	t.Helper()
	server := connectMySQLTestServer(t)
	config := server.createDatabase(t)
	connection := server.connect(t, config)
	if err := database.Migrate(connection.DB, migrationPublicURL); err != nil {
		t.Fatalf("migrate: %v", err)
	}
	return server, config, connection.DB
}

func columnCount(t *testing.T, db *gorm.DB, query string, arguments ...any) int {
	t.Helper()
	var count int
	if err := db.Raw(query, arguments...).Scan(&count).Error; err != nil {
		t.Fatalf("query %q: %v", query, err)
	}
	return count
}

func TestMySQLMigration(t *testing.T) {
	t.Run("Migration on MySQL", func(t *testing.T) {
		_, _, db := migratedMySQL(t)

		for _, table := range []string{"articles", "images", "users", "invites", "api_keys", "purge_settings"} {
			if !db.Migrator().HasTable(table) {
				t.Errorf("table %s must exist", table)
			}
		}
		uniqueColumns := map[string][]string{
			"users":    {"username", "email", "password_reset_code", "verification_code"},
			"api_keys": {"hashed_key"},
		}
		for table, columns := range uniqueColumns {
			for _, column := range columns {
				count := columnCount(t, db, "SELECT COUNT(*) FROM information_schema.statistics WHERE table_schema = DATABASE() AND table_name = ? AND column_name = ? AND non_unique = 0 AND seq_in_index = 1", table, column)
				if count == 0 {
					t.Errorf("a unique index on %s.%s must exist", table, column)
				}
			}
		}
		binaryTables := columnCount(t, db, "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = DATABASE() AND table_collation = 'utf8mb4_bin'")
		if binaryTables != 6 {
			t.Errorf("every table must use the utf8mb4_bin collation, got %d of 6", binaryTables)
		}
	})

	t.Run("migrating twice changes nothing", func(t *testing.T) {
		_, _, db := migratedMySQL(t)

		if err := database.Migrate(db, migrationPublicURL); err != nil {
			t.Errorf("the second migration must succeed: %v", err)
		}
	})

	t.Run("the first user lacking a role becomes owner and the others admin", func(t *testing.T) {
		_, _, db := migratedMySQL(t)
		for _, name := range []string{"first", "second", "third"} {
			insert := db.Exec("INSERT INTO users (username, password, email, role, is_verified, token_version) VALUES (?, 'x', ?, '', 1, 0)", name, name+"@x.example")
			if insert.Error != nil {
				t.Fatalf("insert %s: %v", name, insert.Error)
			}
		}

		if err := database.Migrate(db, migrationPublicURL); err != nil {
			t.Fatalf("migrate: %v", err)
		}

		roles := map[string]string{}
		var users []models.User
		db.Find(&users)
		for _, user := range users {
			roles[user.Username] = user.Role
		}
		if roles["first"] != "owner" || roles["second"] != "admin" || roles["third"] != "admin" {
			t.Errorf("unexpected roles %v", roles)
		}
	})
}

func TestMySQLTimes(t *testing.T) {
	t.Run("times are stored and read back in UTC", func(t *testing.T) {
		_, _, db := migratedMySQL(t)
		repos := newContractRepositories(db)
		zone := time.FixedZone("plus2", 2*3600)
		expiration := time.Date(2030, 5, 6, 7, 8, 9, 0, zone)
		user := contractUser("zoned", "zoned@x.example")
		user.VerificationExpiration = expiration

		created := mustCreateUser(t, repos, user)
		read, err := repos.users.Get(created.ID)

		if err != nil || !read.VerificationExpiration.Equal(expiration) || read.VerificationExpiration.Location() != time.UTC {
			t.Errorf("expected %v in UTC, got %v (%v) err %v", expiration, read.VerificationExpiration, read.VerificationExpiration.Location(), err)
		}
	})

	t.Run("sessions allow the zero date the driver sends for a zero time", func(t *testing.T) {
		_, _, db := migratedMySQL(t)

		var mode string
		if err := db.Raw("SELECT @@SESSION.sql_mode").Scan(&mode).Error; err != nil {
			t.Fatalf("read sql_mode: %v", err)
		}

		if strings.Contains(mode, "NO_ZERO_DATE") || !strings.Contains(mode, "STRICT_TRANS_TABLES") {
			t.Errorf("unexpected session sql_mode %q", mode)
		}
	})
}

func populateForBackup(t *testing.T, repos contractRepositories) {
	t.Helper()
	trickyName := "o'brien \"quoted\" back\\slash\nline é😀"
	mustCreateUser(t, repos, contractUser(trickyName, "tricky@x.example"))
	second := contractUser("plain", "plain@x.example")
	second.PasswordResetCode = "reset-code"
	mustCreateUser(t, repos, second)
	if _, err := repos.articles.Create(domainArticle.Article{Title: "Title", Body: "line1\nline2 'q' \"d\" \\ \x00 end", IsOnline: true}); err != nil {
		t.Fatalf("create article: %v", err)
	}
	mustCreateImage(t, repos, "pic.png", strings.Repeat("c", 64))
	if _, err := repos.invites.Create(domainInvite.Invite{Email: "i@x.example", HashedCode: "h", ExpiresAt: time.Date(2030, 1, 1, 0, 0, 0, 0, time.UTC), InvitedBy: 1}); err != nil {
		t.Fatalf("create invite: %v", err)
	}
}

func steppingClock(start time.Time) func() time.Time {
	current := start
	return func() time.Time {
		current = current.Add(time.Second)
		return current
	}
}

func TestMySQLBackup(t *testing.T) {
	t.Run("Backup before an update", func(t *testing.T) {
		_, _, db := migratedMySQL(t)
		populateForBackup(t, newContractRepositories(db))
		directory := filepath.Join(t.TempDir(), "backups")
		backup := database.NewMySQLBackup(db, directory, steppingClock(time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)))

		var paths []string
		for range 5 {
			path, err := backup.Backup()
			if err != nil {
				t.Fatalf("backup: %v", err)
			}
			paths = append(paths, path)
		}

		entries, _ := os.ReadDir(directory)
		if len(entries) != 3 {
			t.Fatalf("only the 3 newest backups are kept, got %d", len(entries))
		}
		for _, path := range paths[2:] {
			if filepath.Ext(path) != ".sql" || !strings.HasPrefix(filepath.Base(path), "renewcms-") {
				t.Errorf("unexpected backup name %q", path)
			}
			if _, err := os.Stat(path); err != nil {
				t.Errorf("the newest backup %q must remain: %v", path, err)
			}
		}
	})

	t.Run("a failure returns an error and leaves no file", func(t *testing.T) {
		server := connectMySQLTestServer(t)
		connection := server.connect(t, server.createDatabase(t))
		directory := filepath.Join(t.TempDir(), "backups")
		backup := database.NewMySQLBackup(connection.DB, directory, time.Now)
		if err := connection.Close(); err != nil {
			t.Fatalf("close: %v", err)
		}

		path, err := backup.Backup()

		if err == nil || path != "" {
			t.Errorf("expected a failure, got %q %v", path, err)
		}
		if entries, _ := os.ReadDir(directory); len(entries) != 0 {
			t.Errorf("no file may remain, got %d entries", len(entries))
		}
	})

	t.Run("MySQL backup content", func(t *testing.T) {
		server, _, db := migratedMySQL(t)
		repos := newContractRepositories(db)
		populateForBackup(t, repos)
		directory := filepath.Join(t.TempDir(), "backups")
		backup := database.NewMySQLBackup(db, directory, time.Now)

		path, err := backup.Backup()
		if err != nil {
			t.Fatalf("backup: %v", err)
		}
		content, err := os.ReadFile(path)
		if err != nil {
			t.Fatal(err)
		}
		dump := string(content)

		for _, table := range []string{"articles", "images", "users", "invites", "api_keys", "purge_settings"} {
			if !strings.Contains(dump, "CREATE TABLE `"+table+"`") {
				t.Errorf("the dump must contain the schema of %s", table)
			}
		}
		for _, table := range []string{"articles", "images", "users", "invites"} {
			if !strings.Contains(dump, "INSERT INTO `"+table+"`") {
				t.Errorf("the dump must contain rows of %s", table)
			}
		}
		if password := server.config.Password; password != "" && strings.Contains(dump, password) {
			t.Errorf("the dump must not contain the DB_PASSWORD value")
		}

		restoredConfig := server.createDatabase(t)
		replayDump(t, restoredConfig, dump)
		restored := server.connect(t, restoredConfig)
		restoredPath, err := database.NewMySQLBackup(restored.DB, filepath.Join(t.TempDir(), "again"), time.Now).Backup()
		if err != nil {
			t.Fatalf("backup of the restored database: %v", err)
		}
		restoredContent, _ := os.ReadFile(restoredPath)
		if line := firstDifferingLine(withoutRedundantCharset(dump), withoutRedundantCharset(string(restoredContent))); line != "" {
			t.Errorf("replaying the dump must restore the same schema and rows, first difference: %s", line)
		}
		restoredUsers := newContractRepositories(restored.DB).users.GetAll()
		if len(restoredUsers) != 2 || restoredUsers[0].Username != "o'brien \"quoted\" back\\slash\nline é😀" || restoredUsers[1].PasswordResetCode != "reset-code" {
			t.Errorf("unexpected restored users %+v", restoredUsers)
		}
		restoredArticles, _ := newContractRepositories(restored.DB).articles.Get(1)
		if restoredArticles.Body != "line1\nline2 'q' \"d\" \\ \x00 end" {
			t.Errorf("unexpected restored article body %q", restoredArticles.Body)
		}
	})
}

func replayDump(t *testing.T, config database.MySQLConfig, dump string) {
	t.Helper()
	parsed, err := mysqldriver.ParseDSN(database.MySQLDSN(config))
	if err != nil {
		t.Fatal(err)
	}
	parsed.MultiStatements = true
	replay, err := sql.Open("mysql", parsed.FormatDSN())
	if err != nil {
		t.Fatal(err)
	}
	defer replay.Close()
	if _, err := replay.Exec(dump); err != nil {
		t.Fatalf("replay: %v", err)
	}
}

func TestMySQLUsersAreCaseSensitiveThroughTheDomain(t *testing.T) {
	t.Run("Bob and bob can both register", func(t *testing.T) {
		_, _, db := migratedMySQL(t)
		repos := newContractRepositories(db)
		mustCreateUser(t, repos, contractUser("Bob", "b1@x.example"))

		other, err := repos.users.Create(contractUser("bob", "b2@x.example"))
		_, missing := repos.users.GetByUsername("BOB")

		if err != nil || other.Username != "bob" || missing == nil {
			t.Errorf("created %+v err %v, uppercase lookup err %v", other, err, missing)
		}
		if _, err := repos.users.GetByEmail("B1@X.EXAMPLE"); err == nil {
			t.Error("emails are compared exactly like SQLite does")
		}
	})
}

func firstDifferingLine(expected string, actual string) string {
	expectedLines, actualLines := strings.Split(expected, "\n"), strings.Split(actual, "\n")
	for index := 0; index < max(len(expectedLines), len(actualLines)); index++ {
		var want, got string
		if index < len(expectedLines) {
			want = expectedLines[index]
		}
		if index < len(actualLines) {
			got = actualLines[index]
		}
		if want != got {
			return fmt.Sprintf("line %d: want %q got %q", index+1, want, got)
		}
	}
	return ""
}

func withoutRedundantCharset(dump string) string {
	return strings.ReplaceAll(dump, " CHARACTER SET utf8mb4", "")
}