From 8bdb474972d9c86bbd7a287bd17619957261f52b Mon Sep 17 00:00:00 2001
From: yah01 <yah2er0ne@outlook.com>
Date: Wed, 8 Jun 2022 15:29:40 +0800
Subject: [PATCH] Support searching with multiple indexes

Signed-off-by: yah01 <yah2er0ne@outlook.com>
---
 map.go         | 11 ++++++
 search.go      | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++
 search_test.go |  7 ++++
 utils/utils.go | 23 ++++++++++++
 4 files changed, 136 insertions(+)
 create mode 100644 search.go
 create mode 100644 search_test.go
 create mode 100644 utils/utils.go

diff --git a/map.go b/map.go
index af1776c..d6b3227 100644
--- a/map.go
+++ b/map.go
@@ -75,6 +75,17 @@ func (imap *IndexMap[K, V]) GetAllBy(indexName string, key any) []*V {
 	return values.Collect()
 }
 
+// Return all values the seeked by the key,
+// nil if index or key not exists.
+func (imap *IndexMap[K, V]) GetAllByMulti(indexName string, key any) []*V {
+	values := imap.getAllBy(indexName, key)
+	if values == nil {
+		return nil
+	}
+
+	return values.Collect()
+}
+
 // Return true if the value with given key exists,
 // false otherwise.
 func (imap *IndexMap[K, V]) Contain(key K) bool {
diff --git a/search.go b/search.go
new file mode 100644
index 0000000..c41b2ca
--- /dev/null
+++ b/search.go
@@ -0,0 +1,95 @@
+package indexmap
+
+import (
+	"github.com/yah01/container"
+	"github.com/yah01/indexmap/utils"
+)
+
+const (
+	lookupTypeNone lookupType = iota
+	lookupTypeAnd
+	lookupTypeOr
+	lookupTypeExclude
+)
+
+type lookupType int
+
+type indexLookup struct {
+	lookupType lookupType
+	indexName  string
+	keys       []any
+}
+
+type SearchStream[K comparable, V any] struct {
+	chain []*indexLookup
+
+	imap *IndexMap[K, V]
+}
+
+func (stream *SearchStream[K, V]) And(indexName string, keys ...any) *SearchStream[K, V] {
+	stream.chain = append(stream.chain, &indexLookup{
+		lookupType: lookupTypeAnd,
+		indexName:  indexName,
+		keys:       keys,
+	})
+
+	return stream
+}
+
+func (stream *SearchStream[K, V]) Or(indexName string, keys ...any) *SearchStream[K, V] {
+	stream.chain = append(stream.chain, &indexLookup{
+		lookupType: lookupTypeOr,
+		indexName:  indexName,
+		keys:       keys,
+	})
+
+	return stream
+}
+
+func (stream *SearchStream[K, V]) Exclude(indexName string, keys ...any) *SearchStream[K, V] {
+	stream.chain = append(stream.chain, &indexLookup{
+		lookupType: lookupTypeExclude,
+		indexName:  indexName,
+		keys:       keys,
+	})
+
+	return stream
+}
+
+func (stream *SearchStream[K, V]) Excute() []*V {
+	values := make(container.Set[*V])
+
+	for _, lookup := range stream.chain {
+		result := stream.executeLookup(lookup)
+
+		switch lookup.lookupType {
+		case lookupTypeAnd:
+			utils.IntersectSet(values, result)
+
+		case lookupTypeOr:
+			utils.UnionSet(values, result)
+
+		case lookupTypeExclude:
+			utils.ExceptSet(values, result)
+		}
+	}
+
+	return values.Collect()
+}
+
+func (stream *SearchStream[K, V]) executeLookup(lookup *indexLookup) container.Set[*V] {
+	result := make(container.Set[*V])
+	for i := range lookup.keys {
+		utils.UnionSet(result,
+			stream.imap.getAllBy(lookup.indexName, lookup.keys[i]))
+	}
+
+	return result
+}
+
+func (imap *IndexMap[K, V]) Search() *SearchStream[K, V] {
+	return &SearchStream[K, V]{
+		chain: make([]*indexLookup, 0),
+		imap:  imap,
+	}
+}
diff --git a/search_test.go b/search_test.go
new file mode 100644
index 0000000..33f8bf6
--- /dev/null
+++ b/search_test.go
@@ -0,0 +1,7 @@
+package indexmap
+
+import "testing"
+
+func TestSearch(t *testing.T) {
+	
+}
\ No newline at end of file
diff --git a/utils/utils.go b/utils/utils.go
new file mode 100644
index 0000000..5ffbd19
--- /dev/null
+++ b/utils/utils.go
@@ -0,0 +1,23 @@
+package utils
+
+import "github.com/yah01/container"
+
+func UnionSet[T comparable](dst container.Set[T], src container.Set[T]) {
+	for elem := range src {
+		dst.Insert(elem)
+	}
+}
+
+func IntersectSet[T comparable](dst container.Set[T], src container.Set[T]) {
+	for elem := range dst {
+		if !src.Contain(elem) {
+			delete(dst, elem)
+		}
+	}
+}
+
+func ExceptSet[T comparable](dst container.Set[T], src container.Set[T]) {
+	for elem := range src {
+		delete(dst, elem)
+	}
+}