/*
Copyright 2011 Google Inc.

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 search

import (
	"camli/blobref"

	"os"
	"time"
)

type Result struct {
	BlobRef     *blobref.BlobRef
	Signer      *blobref.BlobRef // may be nil
	LastModTime int64            // seconds since epoch
}

// TODO: move this to schema or something?
type Claim struct {
	BlobRef, Signer, Permanode *blobref.BlobRef

	Date *time.Time
	Type string // "set-attribute", "add-attribute", etc

	// If an attribute modification
	Attr, Value string
}

type ClaimList []*Claim

func (cl ClaimList) Len() int {
	return len(cl)
}

func (cl ClaimList) Less(i, j int) bool {
	// TODO: memoize Seconds in unexported Claim field
	return cl[i].Date.Seconds() < cl[j].Date.Seconds()
}

func (cl ClaimList) Swap(i, j int) {
	cl[i], cl[j] = cl[j], cl[i]
}

type FileInfo struct {
	Size     int64
	FileName string
	MimeType string
}

type Path struct {
	Claim, Base *blobref.BlobRef
	ClaimDate   string
	Suffix      string
}

type Index interface {
	// dest is closed
	// limit is <= 0 for default.  smallest possible default is 0
	GetRecentPermanodes(dest chan *Result,
	owner []*blobref.BlobRef,
	limit int) os.Error

	GetOwnerClaims(permaNode, owner *blobref.BlobRef) (ClaimList, os.Error)

	GetBlobMimeType(blob *blobref.BlobRef) (mime string, size int64, err os.Error)

	// ExistingFileSchemas returns 0 or more blobrefs of file
	// schema blobs that represent the bytes of a file given in
	// bytesRef.  The file schema blobs returned are not
	// guaranteed to reference chunks that still exist on the
	// blobservers, though.  It's purely a hint for clients to
	// avoid uploads if possible.  Before re-using any returned
	// blobref they should be checked.
	ExistingFileSchemas(bytesRef *blobref.BlobRef) ([]*blobref.BlobRef, os.Error)

	GetFileInfo(fileRef *blobref.BlobRef) (*FileInfo, os.Error)

	// Given an owner key, a camliType 'claim', 'attribute' name,
	// and specific 'value', find the most recent permanode that has
	// a corresponding 'set-attribute' claim attached.
	PermanodeOfSignerAttrValue(signer *blobref.BlobRef, attr, val string) (*blobref.BlobRef, os.Error)

	PathsOfSignerTarget(signer *blobref.BlobRef, target *blobref.BlobRef) ([]*Path, os.Error)
}