From e6acf6c41c56e175a2f94313b1f76ebfc9c6278d Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Wed, 11 Feb 2015 01:24:29 +0700
Subject: [PATCH] Chain parser

---
 core/parser.go | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 core/parser.go

diff --git a/core/parser.go b/core/parser.go
new file mode 100644
index 0000000..1b8e27d
--- /dev/null
+++ b/core/parser.go
@@ -0,0 +1,58 @@
+package core
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+)
+
+func ParseChains(b []byte) (map[string]*Chain, error) {
+	var schema map[string]interface{}
+	if err := json.Unmarshal(b, &schema); err != nil {
+		return nil, err
+	}
+
+	chains := map[string]*Chain{}
+	for name, chain := range schema {
+		chains[name] = buildChain(interface{}(chain))
+	}
+
+	return chains, nil
+}
+
+func buildChain(conf interface{}) *Chain {
+	c := &Chain{
+		Links: []Caller{},
+	}
+
+	for flow, links := range conf.(map[string]interface{}) {
+		if f, ok := FlowMap[flow]; ok {
+			c.Flow = f
+		} else {
+			panic("Unknown chain flow: " + flow)
+		}
+
+		for _, link := range links.([]interface{}) {
+			val := reflect.ValueOf(link)
+
+			switch val.Kind() {
+			case reflect.Map:
+				subchain := buildChain(interface{}(link))
+				if len(subchain.Links) > 0 {
+					c.Links = append(c.Links, Caller(subchain))
+				}
+			case reflect.String:
+				unit, ok := Units[link.(string)]
+				if !ok {
+					fmt.Println("Unknown unit `" + link.(string) + "`")
+				} else {
+					c.Links = append(c.Links, unit)
+				}
+			default:
+				panic("Unexpected chain element: " + val.Kind().String())
+			}
+		}
+	}
+
+	return c
+}