// Copyright 2015 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package logpb

import (
	"errors"
	"fmt"
	"reflect"

	"go.chromium.org/luci/logdog/common/types"
)

var (
	// ErrNoContent indicates that a LogEntry has no data content.
	ErrNoContent = errors.New("no content")
)

// Validate returns an error if the supplied LogStreamDescriptor is not complete
// and valid.
//
// If prefix is true, the Prefix field will be validated; otherwise, it will
// be ignored. This can be useful when attempting to validate a
// LogStreamDescriptor before the application-assigned Prefix is known.
func (d *LogStreamDescriptor) Validate(prefix bool) error {
	if d == nil {
		return errors.New("descriptor is nil")
	}

	if prefix {
		if err := types.StreamName(d.Prefix).Validate(); err != nil {
			return fmt.Errorf("invalid prefix: %s", err)
		}
	}
	if err := types.StreamName(d.Name).Validate(); err != nil {
		return fmt.Errorf("invalid name: %s", err)
	}

	switch d.StreamType {
	case StreamType_TEXT, StreamType_BINARY, StreamType_DATAGRAM:
		break

	default:
		return fmt.Errorf("invalid stream type: %v", d.StreamType)
	}

	if d.ContentType == "" {
		return errors.New("missing content type")
	}

	if d.Timestamp == nil {
		return errors.New("missing timestamp")
	}
	for k, v := range d.GetTags() {
		if err := types.ValidateTag(k, v); err != nil {
			return fmt.Errorf("invalid tag %q: %v", k, err)
		}
	}
	return nil
}

// Equal tests if two LogStreamDescriptor instances have the same data.
func (d *LogStreamDescriptor) Equal(o *LogStreamDescriptor) bool {
	return reflect.DeepEqual(d, o)
}

// Path returns a types.StreamPath constructed from the LogStreamDesciptor's
// Prefix and Name fields.
func (d *LogStreamDescriptor) Path() types.StreamPath {
	return types.StreamName(d.Prefix).Join(types.StreamName(d.Name))
}

// Validate checks a supplied LogEntry against its LogStreamDescriptor for
// validity, returning an error if it is not valid.
//
// If the LogEntry is otherwise valid, but has no content, ErrNoContent will be
// returned.
func (e *LogEntry) Validate(d *LogStreamDescriptor) error {
	if e == nil {
		return errors.New("entry is nil")
	}

	// Check for content.
	switch d.StreamType {
	case StreamType_TEXT:
		if t := e.GetText(); t == nil || len(t.Lines) == 0 {
			return ErrNoContent
		}

	case StreamType_BINARY:
		if b := e.GetBinary(); b == nil || len(b.Data) == 0 {
			return ErrNoContent
		}

	case StreamType_DATAGRAM:
		if d := e.GetDatagram(); d == nil {
			return ErrNoContent
		}
	}
	return nil
}