fraenky8 / tables-to-go

import (

	"fmt"

	"strings"

	"github.com/fraenky8/tables-to-go/pkg/config"

	"github.com/fraenky8/tables-to-go/pkg/database"

	"github.com/fraenky8/tables-to-go/pkg/output"

	"github.com/fraenky8/tables-to-go/pkg/tagger"

)

var (

	taggers tagger.Tagger

	// some strings for idiomatic go in column names

	// see https://github.com/golang/go/wiki/CodeReviewComments#initialisms

	initialisms = []string{"ID", "JSON", "XML", "HTTP", "URL"}

)

// Run runs the transformations by creating the concrete Database by the provided settings

func Run(settings *config.Settings, db database.Database, out output.Writer) (err error) {

	taggers = tagger.NewTaggers(settings)

	fmt.Printf("running for %q...\r\n", settings.DbType)

	tables, err := db.GetTables()

	if err != nil {

		return fmt.Errorf("could not get tables: %v", err)

	}

	if settings.Verbose {

		fmt.Printf("> number of tables: %v\r\n", len(tables))

	}

	if err = db.PrepareGetColumnsOfTableStmt(); err != nil {

		return fmt.Errorf("could not prepare the get-column-statement: %v", err)

	}

	for _, table := range tables {

		if settings.Verbose {

			fmt.Printf("> processing table %q\r\n", table.Name)

		}

		if err = db.GetColumnsOfTable(table); err != nil {

			return fmt.Errorf("could not get columns of table %s: %v", table.Name, err)

		}

		if settings.Verbose {

			fmt.Printf("\t> number of columns: %v\r\n", len(table.Columns))

		}

		tableName, content := createTableStructString(settings, db, table)

		err = out.Write(tableName, content)

		if err != nil {

			return fmt.Errorf("could not write struct for table %s: %v", table.Name, err)

		}

	}

	fmt.Println("done!")

	return nil

}

type columnInfo struct {

	isNullable          bool

	isTemporal          bool

	isNullablePrimitive bool

	isNullableTemporal  bool

}

func createTableStructString(settings *config.Settings, db database.Database, table *database.Table) (string, string) {

	var structFields strings.Builder

	columnInfo := columnInfo{}

	columns := map[string]struct{}{}

	for _, column := range table.Columns {

		columnName := strings.Title(column.Name)

		if settings.IsOutputFormatCamelCase() {

			columnName = camelCaseString(column.Name)

		}

		if settings.ShouldInitialism() {

			columnName = toInitialisms(columnName)

		}

		// ISSUE-4: if columns are part of multiple constraints

		// then the sql returns multiple rows per column name.

		// Therefore we check if we already added a column with

		// that name to the struct, if so, skip.

		if _, ok := columns[columnName]; ok {

			continue

		}

		columns[columnName] = struct{}{}

		if settings.VVerbose {

			fmt.Printf("\t\t> %v\r\n", column.Name)

		}

		columnType, col := mapDbColumnTypeToGoType(settings, db, column)

		// save that we saw types of columns at least once

		if !columnInfo.isTemporal {

			columnInfo.isTemporal = col.isTemporal

		}

		if !columnInfo.isNullableTemporal {

			columnInfo.isNullableTemporal = col.isNullableTemporal

		}

		if !columnInfo.isNullablePrimitive {

			columnInfo.isNullablePrimitive = col.isNullablePrimitive

		}

		structFields.WriteString(columnName)

		structFields.WriteString(" ")

		structFields.WriteString(columnType)

		structFields.WriteString(" ")

		structFields.WriteString(taggers.GenerateTag(db, column))

		structFields.WriteString("\n")

	}

	if settings.IsMastermindStructableRecorder {

		structFields.WriteString("\t\nstructable.Recorder\n")

	}

	var fileContent strings.Builder

	// write header infos

	fileContent.WriteString("package ")

	fileContent.WriteString(settings.PackageName)

	fileContent.WriteString("\n\n")

	// write imports

	generateImports(&fileContent, settings, db, columnInfo)

	tableName := strings.Title(settings.Prefix + table.Name + settings.Suffix)

	if settings.IsOutputFormatCamelCase() {

		tableName = camelCaseString(tableName)

	}

	// write struct with fields

	fileContent.WriteString("type ")

	fileContent.WriteString(tableName)

	fileContent.WriteString(" struct {\n")

	fileContent.WriteString(structFields.String())

	fileContent.WriteString("}")

	return tableName, fileContent.String()

}

func generateImports(content *strings.Builder, settings *config.Settings, db database.Database, columnInfo columnInfo) {

	if !columnInfo.hasTrue() && !settings.IsMastermindStructableRecorder {

		return

	}

	content.WriteString("import (\n")

	if columnInfo.isNullablePrimitive && settings.IsNullTypeSQL() {

		content.WriteString("\t\"database/sql\"\n")

	}

	if columnInfo.isTemporal {

		content.WriteString("\t\"time\"\n")

	}

	if columnInfo.isNullableTemporal && settings.IsNullTypeSQL() {

		content.WriteString("\t\n")

		content.WriteString(db.GetDriverImportLibrary())

		content.WriteString("\n")

	}

	if settings.IsMastermindStructableRecorder {

		content.WriteString("\t\n\"github.com/Masterminds/structable\"\n")

	}

	content.WriteString(")\n\n")

}

func mapDbColumnTypeToGoType(settings *config.Settings, db database.Database, column database.Column) (goType string, columnInfo columnInfo) {

	if db.IsString(column) || db.IsText(column) {

		goType = "string"

		if db.IsNullable(column) {

			goType = getNullType(settings, "*string", "sql.NullString")

			columnInfo.isNullable = true

		}

	} else if db.IsInteger(column) {

		goType = "int"

		if db.IsNullable(column) {

			goType = getNullType(settings, "*int", "sql.NullInt64")

			columnInfo.isNullable = true

		}

	} else if db.IsFloat(column) {

		goType = "float64"

		if db.IsNullable(column) {

			goType = getNullType(settings, "*float64", "sql.NullFloat64")

			columnInfo.isNullable = true

		}

	} else if db.IsTemporal(column) {

		if !db.IsNullable(column) {

			goType = "time.Time"

			columnInfo.isTemporal = true

		} else {

			goType = getNullType(settings, "*time.Time", db.GetTemporalDriverDataType())

			columnInfo.isTemporal = settings.Null == config.NullTypeNative

			columnInfo.isNullableTemporal = true

			columnInfo.isNullable = true

		}

	} else {

		// TODO handle special data types

		switch column.DataType {

		case "boolean":

			goType = "bool"

			if db.IsNullable(column) {

				goType = getNullType(settings, "*bool", "sql.NullBool")

				columnInfo.isNullable = true

			}

		default:

			goType = getNullType(settings, "*string", "sql.NullString")

		}

	}

	columnInfo.isNullablePrimitive = columnInfo.isNullable && !db.IsTemporal(column)

	return goType, columnInfo

}

func getNullType(settings *config.Settings, primitive string, sql string) string {

	if settings.IsNullTypeSQL() {

		return sql

	}

	return primitive

}

func camelCaseString(s string) (cc string) {

	splitted := strings.Split(s, "_")

	if len(splitted) == 1 {

		return strings.Title(s)

	}

	for _, part := range splitted {

		cc += strings.Title(strings.ToLower(part))

	}

	return cc

}

func toInitialisms(s string) string {

	for _, substr := range initialisms {

		idx := indexCaseInsensitive(s, substr)

		if idx == -1 {

			continue

		}

		toReplace := s[idx : idx+len(substr)]

		s = strings.ReplaceAll(s, toReplace, substr)

	}

	return s

}

func indexCaseInsensitive(s, substr string) int {

	s, substr = strings.ToLower(s), strings.ToLower(substr)

	return strings.Index(s, substr)

}