orm/table.go

package orm

import (
	"fmt"
	"math"
	"reflect"
	"strconv"
	"sync"

	"github.com/go-openapi/inflect"
)

type table struct {
	rt       reflect.Type
	rv       reflect.Value
	l        *sync.RWMutex
	tFn, cFn MapperFn
	cols     columns
	rels     relations
	mapped   bool
}

func (t *table) Make() MappableInterface {
	return reflect.New(t.getType()).Interface().(MappableInterface)
}

func (t *table) CallMethod(i MappableInterface, n string, args ...interface{}) ([]interface{}, error) {
	var ret []interface{}
	if t.getValue(true).MethodByName(n).IsValid() {
		fn := reflect.ValueOf(i).MethodByName(n)
		fnt := fn.Type()
		in := []reflect.Value{}

		if fnt.IsVariadic() && len(args) < (fnt.NumIn()-1) {
			return ret, fmt.Errorf("To few arguments to «%s». Got «%d», expected «%d»", n, len(args), fnt.NumIn()-1)
		} else if !fnt.IsVariadic() && len(args) != fnt.NumIn() {
			return ret, fmt.Errorf("To few arguments to «%s». Got «%d», expected «%d»", n, len(args), fnt.NumIn()-1)
		}

		for x := 0; x < len(args); x++ {

			var inType reflect.Type
			if fnt.IsVariadic() && x >= fnt.NumIn()-1 {
				inType = fnt.In(fnt.NumIn() - 1).Elem()
			} else {
				inType = fnt.In(x)
			}

			argv := reflect.ValueOf(args[x])

			if !argv.IsValid() || !argv.Type().ConvertibleTo(inType) {

				switch inType.Kind() {
				case
					reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
					reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
					var val uint64 = 0
					argx := args[x].([]uint8)
					for xi := len(argx) - 1; xi >= 0; xi-- {
						val += uint64(math.Pow(10, float64(len(argx)-xi-1))) * uint64(argx[xi]-'0')
					}
					args[x] = val
					return t.CallMethod(i, n, args...)
				case reflect.Float32, reflect.Float64:
					if val, err := strconv.ParseFloat(string(args[x].([]byte)), 64); err == nil {
						args[x] = val
						return t.CallMethod(i, n, args...)
					}
				case reflect.Complex64, reflect.Complex128:
					// Not implemented
					return ret, fmt.Errorf("Complex not implemented")
				}

				return ret, fmt.Errorf("Invalid argument to «%s». Got %s, expected %s", n, argv.String(), inType.String())
			}

			in = append(in, argv.Convert(inType))
		}

		var err error = nil
		out := fn.Call(in)[0:fnt.NumOut()]

		for _, val := range out {
			switch val.Kind() {
			case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
				ret = append(ret, val.Uint())
			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
				ret = append(ret, val.Int())
			case reflect.Float32, reflect.Float64:
				ret = append(ret, val.Float())
			case reflect.String:
				ret = append(ret, val.String())
			case reflect.Interface:
				if !val.IsNil() && val.CanInterface() && val.Type().Implements(reflect.TypeOf((*error)(nil)).Elem()) {
					err = val.Interface().(error)
				}
			}
		}

		return ret, err

	}

	return ret, fmt.Errorf("Invalid method «%s» on «%s»", n, t.getType())
}

// getPrimaryKey tries to find primary key
func (t *table) getPrimaryKey() *column {
	var pkey *column = nil

	if c := t.hasTaggedColumn("primary"); c != nil {
		pkey = c
	} else if c := t.hasColumn("Id"); c != nil {
		pkey = c
	}

	return pkey
}

func (t *table) getRelations() map[relType][]relation {
	return t.rels.rmap
}

func (t *table) getColumns() columns {
	return t.cols
}

// hasTaggetColumn checks for a collumn tagget as
func (t *table) hasTaggedColumn(ct string) *column {
	for _, col := range t.cols {
		if col.hasTag(ct) {
			return &col
		}
	}
	return nil
}

// hasColumn checks for a column by name
func (t *table) hasColumn(c string) *column {
	for _, col := range t.cols {
		if col.ref == t.cFn(c) {
			return &col
		}
	}
	return nil
}

// addField from struct; both «relations» and «columns»
// Communicates over a channel, to do relation mapping
func (t *table) addField(f field, cbCh chan<- mapperCallback) {

	if f.hasTags("omit", "-") {
		return // Skip "omitted" and "dashed" fields
	}

	switch f.getType() {
	case Relation:

		// Make callback to itself, relations should be mapped after columns
		cbCh <- mapperCallback{
			from: t.getStructName(),
			to:   t.getStructName(),

			fn: func(self *table) {
				// Get Primary Key
				pkey := self.getPrimaryKey()

				// Or at least try to
				if pkey == nil {
					return
				}

				// Predict related table name
				rtbl := f.getFieldType()

				// And check for tag
				if tag, ok := f.getTag("table"); ok {
					rtbl = tag
				}

				// Predict column name
				cn := f.getFieldName() + "Id"

				// And check for tag
				if tag, ok := f.getTag("fkey"); ok {
					cn = tag
				}

				/*
					if self.getStructName() == "PlatformCalendar" {
						fmt.Println(self.getStructName(), f.getFieldType(), cn)
					}
				*/

				// Check if it contains reference itself
				if c := self.hasColumn(cn); c != nil {
					// Make a call to load related table into scope;
					// we need its addr and must be loaded from mapper
					cbCh <- mapperCallback{
						from: self.getStructName(),
						to:   rtbl,
						fn: func(tbl *table) {
							key := tbl.getPrimaryKey()
							self.rels.addRelation(belongsTo, relation{tbl, f, *key, *c})
						},
					}
				} else {

					// Or predict column name in related table
					cn = self.getStructName() + "Id"

					// Check for reference tag
					if tag, ok := f.getTag("ref"); ok {
						cn = tag
					}

					// Make a callback to the related table to check for relationg
					cbCh <- mapperCallback{
						from: self.getStructName(),
						to:   rtbl,
						fn: func(tbl *table) {

							// Check for relation on column mane
							if c := tbl.hasColumn(cn); c != nil {

								// Predict the relations is «hasOne»
								has := hasOne

								// Try to predict (or simply guess) with pluralization, if «hasMany»
								if inflect.Pluralize(f.getFieldName()) == f.getFieldName() {
									has = hasMany
								}

								// Override with tagging if specified
								if tag, ok := f.getTag("has"); ok {
									switch tag {
									case "many":
										has = hasMany
									case "one":
										has = hasOne
									}
								}

								self.rels.addRelation(has, relation{tbl, f, *c, *pkey})
							}
						},
					}
				}
				return
			},
		}

	default: // Add column
		switch f.getKind() {
		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
			fallthrough // Support all Uint types
		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
			fallthrough // Support all Int types
		case reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
			fallthrough // Support all Float and Complex types
		case reflect.String, reflect.Bool:
			// Support string and boolean

			// Map column name
			dbf := t.cFn(f.getFieldName())

			// override with tagging
			if tag, ok := f.getTag("field"); ok {
				dbf = t.cFn(tag)
			}

			t.cols = append(t.cols, column{
				f, dbf,
			})
		default:
			fmt.Println(t.getStructName(), "not supporting", f)
		}
	}
}

// getType returns the reflect.Type of the «table»
func (t *table) getType() reflect.Type {
	return t.rt
}

// getValue returns the reflect.Value of the «table»
func (t *table) getValue(ptr ...bool) reflect.Value {
	if len(ptr) > 0 && ptr[0] {
		return t.rv
	}
	return t.rv.Elem()
}

// isMapped returns true when columns is mapped
// Not relations! They will be mapped in separate routines
func (t *table) isMapped() bool {
	return t.mapped
}

// Lock read lock
func (t *table) Lock() *table {
	t.l.RLock()
	return t
}

// Unlock read lock
func (t *table) Unlock() {
	t.l.RUnlock()
}

// lock write lock
func (t *table) lock() *table {
	t.l.Lock()
	return t
}

// unlock write lock
func (t *table) unlock() {
	t.l.Unlock()
}

// getStructName returns the name of the struct
func (t *table) getStructName() string {
	return t.getType().Name()
}

// getName returns the mapped table name
// as identified in the database
func (t *table) getName(q bool) string {
	if q {
		return SqlFlavor.Quote(t.getName(false))
	}
	return t.tFn(t.getType().Name())
}

func (t *table) getNameAs(q bool) string {
	return t.getName(q) + " AS " + t.getAlias(q)
}

func (t *table) getAlias(q bool) string {
	if q {
		return SqlFlavor.Quote(t.getAlias(false))
	}

	return t.getStructName()
}

// tables is simply a collection of tables
type tables map[string]*table