From 9fd13f759ab9d847c50a1caf5fb27285e278b8e5 Mon Sep 17 00:00:00 2001
From: Quentin Dufour <quentin@deuxfleurs.fr>
Date: Wed, 21 Apr 2021 22:29:17 +0200
Subject: [PATCH] Find HEAD is implemented

---
 commit.go | 132 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 109 insertions(+), 23 deletions(-)

diff --git a/commit.go b/commit.go
index a97762d..27525d2 100644
--- a/commit.go
+++ b/commit.go
@@ -2,41 +2,58 @@ package main
 
 import (
   "encoding/json"
+  "fmt"
   "log"
+  "time"
   "io/ioutil"
   "path/filepath"
 )
 
+type Empty struct{}
+var empty Empty
+
 type RepoCommits struct {
   Config configCollect
   CommitDesc map[string]string
-  CommitContent map[string]Commit
+  CommitContent map[string]*CommitNode
   Head *CommitNode
+  Root *CommitNode
 }
 
 type CommitNode struct {
-  Parents []*CommitNode
-  Children []*CommitNode
+  Parents map[*CommitNode]Empty
+  Children map[*CommitNode]Empty
   Content Commit
 }
 
 type Commit struct {
-  CommitId string `json:"commit_id"`
-  RootId string `json:"root_id"`
-  RepoId string `json:"repo_id"`
-  CreatorName string `json:"creator_name"`
-  Creator string `json:"creator"`
-  Description string `json:"description"`
-  Ctime uint64 `json:"ctime"`
-  ParentId string `json:"parent_id"`
-  SecondParentId string `json:"second_parent_id"`
-  RepoName string `json:"repo_name"`
-  RepoDesc string `json:"repo_desc"`
-  RepoCategory string `json:"repo_category"`
+  CommitId *string `json:"commit_id"`
+  RootId *string `json:"root_id"`
+  RepoId *string `json:"repo_id"`
+  CreatorName *string `json:"creator_name"`
+  Creator *string `json:"creator"`
+  Description *string `json:"description"`
+  Ctime int64 `json:"ctime"`
+  ParentId *string `json:"parent_id"`
+  SecondParentId *string `json:"second_parent_id"`
+  RepoName *string `json:"repo_name"`
+  RepoDesc *string `json:"repo_desc"`
+  RepoCategory *string `json:"repo_category"`
   NoLocalHistory int `json:"no_local_history"`
   Version int `json:"version"`
 }
 
+func (c* Commit) String() string {
+  return fmt.Sprintf(`RootId: %s
+CreatorName: %s
+Creator: %s
+Description: %s
+Ctime: %s
+RepoName: %s
+RepoDesc: %s
+`, *c.RootId, *c.CreatorName, *c.Creator, *c.Description, time.Unix(c.Ctime, 0), *c.RepoName, *c.RepoDesc)
+}
+
 func cmdCommit(config configCollect) {
   rc := NewRepoCommits(config)
 
@@ -44,20 +61,21 @@ func cmdCommit(config configCollect) {
   rc.PrintDescs()
 
   rc.CollectContent()
-  //rc.BuildGraph()
+  rc.BuildGraph()
+  rc.FindHead()
+  rc.PrintHead()
 }
 
 func NewRepoCommits (config configCollect) *RepoCommits {
   rc := new(RepoCommits)
   rc.Config =  config
   rc.CommitDesc = make(map[string]string)
-  rc.CommitContent = make(map[string]Commit)
+  rc.CommitContent = make(map[string]*CommitNode)
   return rc
 }
 
 func (rc* RepoCommits) CollectDescs() {
   baseFolder := filepath.Join(rc.Config.Storage, "commits", rc.Config.RepoId)
-  log.Println(baseFolder)
   layer1, err := ioutil.ReadDir(baseFolder)
   if err != nil { log.Fatal(err) }
   for _, l1 := range layer1 {
@@ -73,7 +91,7 @@ func (rc* RepoCommits) CollectDescs() {
 }
 
 func (rc* RepoCommits) PrintDescs() {
-  limit := 10
+  /*limit := 10
   for id, path := range rc.CommitDesc {
     log.Println(id, path)
     limit = limit - 1
@@ -81,18 +99,86 @@ func (rc* RepoCommits) PrintDescs() {
       log.Println("Too many commits, output has been truncated")
       break
     }
-  }
+  }*/
   log.Println("Repo", rc.Config.RepoId, "contains", len(rc.CommitDesc), "commits")
 }
 
+func NewCommitNode(c Commit) *CommitNode {
+  cn := new(CommitNode)
+  cn.Content = c
+  cn.Parents = make(map[*CommitNode]Empty)
+  cn.Children = make(map[*CommitNode]Empty)
+
+  return cn
+}
+
 func (rc* RepoCommits) CollectContent() {
   for id, path := range rc.CommitDesc {
     data, err := ioutil.ReadFile(path)
     if err != nil { log.Fatal(err) }
 
-    var c Commit
+    var c Commit;
     json.Unmarshal(data, &c)
-    rc.CommitContent[id] = c
-    log.Println(rc.CommitContent[id])
+    rc.CommitContent[id] = NewCommitNode(c)
   }
 }
+
+func (rc* RepoCommits) BuildGraph() *CommitNode {
+  for _, cn := range rc.CommitContent {
+    if cn.Content.ParentId == nil && cn.Content.SecondParentId == nil {
+      if rc.Root == nil {
+        rc.Root = cn
+      } else {
+        log.Fatal("More than one root commit has been found")
+      }
+    }
+
+    if cn.Content.ParentId != nil {
+      parentCn := rc.CommitContent[*cn.Content.ParentId]
+      cn.Parents[parentCn] = empty
+      parentCn.Children[cn] = empty
+    }
+
+    if cn.Content.SecondParentId != nil {
+      parentCn := rc.CommitContent[*cn.Content.SecondParentId]
+      cn.Parents[parentCn] = empty
+      parentCn.Children[cn] = empty
+    }
+  }
+
+  if rc.Root == nil {
+    log.Fatal("Root commit has not been found")
+  }
+
+  return rc.Root
+}
+
+func (rc* RepoCommits) FindHead() *CommitNode {
+  toProcess := make(map[*CommitNode]Empty)
+  toProcess[rc.Root] = empty
+
+  for i := 0; i < len(rc.CommitContent) && len(toProcess) > 0; i++ {
+    nextToProcess := make(map[*CommitNode]Empty)
+    for cn, _ := range toProcess {
+      for ccn, _ := range cn.Children {
+        nextToProcess[ccn] = empty
+      }
+      if len(cn.Children) == 0 {
+        if rc.Head == nil { 
+          rc.Head = cn 
+        } else { 
+          log.Fatal("More than one HEAD has been found") 
+        }
+      }
+    }
+
+    toProcess = nextToProcess
+  }
+
+  if rc.Head == nil { log.Fatal("No HEAD has been found") }
+  return rc.Head
+}
+
+func (rc* RepoCommits) PrintHead() {
+  log.Println(rc.Head.Content.String())
+}