From 74d360f6d7c50fd9a312b666f8fcfb3df99f4803 Mon Sep 17 00:00:00 2001
From: stephen mcquay <stephen@mcquay.me>
Date: Fri, 2 Mar 2018 23:23:11 -0800
Subject: [PATCH] Adds pm pull

---
 available.go      | 12 ++++++++++
 available_test.go | 10 ++++++++
 meta.go           |  7 +++++-
 remote/pull.go    | 59 +++++++++++++++++++++++++++++++++++++++++++++--
 remote/remote.go  | 10 ++++----
 5 files changed, 90 insertions(+), 8 deletions(-)

diff --git a/available.go b/available.go
index fc2d0a2..89e0b51 100644
--- a/available.go
+++ b/available.go
@@ -1,6 +1,8 @@
 package pm
 
 import (
+	"net/url"
+
 	"github.com/pkg/errors"
 )
 
@@ -38,3 +40,13 @@ func (a Available) Update(o Available) error {
 	}
 	return nil
 }
+
+func (a Available) SetRemote(u url.URL) {
+	for n, vers := range a {
+		for v, _ := range vers {
+			m := a[n][v]
+			m.Remote = u
+			a[n][v] = m
+		}
+	}
+}
diff --git a/available_test.go b/available_test.go
index 18f466c..4c87420 100644
--- a/available_test.go
+++ b/available_test.go
@@ -2,6 +2,7 @@ package pm
 
 import (
 	"errors"
+	"net/url"
 	"testing"
 )
 
@@ -92,4 +93,13 @@ func TestAvailableUpdate(t *testing.T) {
 	if got, want := a["a"]["v1.0.0"].Description, "test last in"; got != want {
 		t.Fatalf("last in didn't override")
 	}
+
+	u, err := url.Parse("https://pm.mcquay.me/darwin/amd64")
+	if err != nil {
+		t.Fatalf("parsing url: %v", err)
+	}
+	a.SetRemote(*u)
+	if got, want := a["a"]["v1.0.0"].Remote, *u; got != want {
+		t.Fatalf("last in didn't override")
+	}
 }
diff --git a/meta.go b/meta.go
index f6ff091..fade179 100644
--- a/meta.go
+++ b/meta.go
@@ -1,6 +1,9 @@
 package pm
 
-import "errors"
+import (
+	"errors"
+	"net/url"
+)
 
 // Meta tracks metadata for a package
 type Meta struct {
@@ -8,6 +11,8 @@ type Meta struct {
 	Version     Version `json:"version"`
 	Description string  `json:"description"`
 	Namespace   string  `json:"namespace"`
+
+	Remote url.URL `json:"remote"`
 }
 
 // Valid validates the contents of a Meta for requires fields.
diff --git a/remote/pull.go b/remote/pull.go
index 5204052..add328f 100644
--- a/remote/pull.go
+++ b/remote/pull.go
@@ -1,8 +1,63 @@
 package remote
 
-import "github.com/pkg/errors"
+import (
+	"encoding/json"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"mcquay.me/pm"
+)
+
+const an = "var/lib/pm/available.json"
 
 // Pull updates the available package database.
 func Pull(root string) error {
-	return errors.New("NYI")
+	db, err := load(root)
+	if err != nil {
+		return errors.Wrap(err, "loading db")
+	}
+
+	o := pm.Available{}
+
+	// Order here is important: the guarantee made is that any packages that
+	// exist in multiple remotes will be fetched by the first configured
+	// remote, which is why we traverse the database in reverse.
+	//
+	// TODO (sm): make this concurrent
+	for i := range db {
+		u := db[len(db)-i-1]
+		resp, err := http.Get(u.String() + "/available.json")
+		if err != nil {
+			return errors.Wrap(err, "http get")
+		}
+
+		a := pm.Available{}
+		if err := json.NewDecoder(resp.Body).Decode(&a); err != nil {
+			return errors.Wrap(err, "decode remote available")
+		}
+		a.SetRemote(u)
+		o.Update(a)
+	}
+	if err := saveAvailable(root, o); err != nil {
+		return errors.Wrap(err, "saving available db")
+	}
+	return nil
+}
+
+func saveAvailable(root string, db pm.Available) error {
+	f, err := os.Create(filepath.Join(root, an))
+	if err != nil {
+		return errors.Wrap(err, "create")
+	}
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "\t")
+	if err := enc.Encode(&db); err != nil {
+		return errors.Wrap(err, "decoding db")
+	}
+	if err := f.Close(); err != nil {
+		return errors.Wrap(err, "close db")
+	}
+	return nil
 }
diff --git a/remote/remote.go b/remote/remote.go
index 8e438ff..93b9247 100644
--- a/remote/remote.go
+++ b/remote/remote.go
@@ -15,7 +15,7 @@ import (
 // DB is a slice of available URI
 type DB []url.URL
 
-const fn = "var/lib/pm/available.json"
+const rn = "var/lib/pm/remotes.json"
 
 // Add appends the provided uri to the list of configured remotes.
 func Add(root string, uris []string) error {
@@ -93,13 +93,13 @@ func List(root string, w io.Writer) error {
 
 func load(root string) (DB, error) {
 	r := DB{}
-	dbn := filepath.Join(root, fn)
+	dbn := filepath.Join(root, rn)
 
 	if !fs.Exists(dbn) {
 		return r, nil
 	}
 
-	f, err := os.Open(filepath.Join(root, fn))
+	f, err := os.Open(filepath.Join(root, rn))
 	if err != nil {
 		return r, errors.Wrap(err, "open")
 	}
@@ -112,7 +112,7 @@ func load(root string) (DB, error) {
 }
 
 func save(root string, db DB) error {
-	f, err := os.Create(filepath.Join(root, fn))
+	f, err := os.Create(filepath.Join(root, rn))
 	if err != nil {
 		return errors.Wrap(err, "create")
 	}
@@ -140,7 +140,7 @@ func strip(u url.URL) url.URL {
 }
 
 func mkdirs(root string) error {
-	d, _ := filepath.Split(filepath.Join(root, fn))
+	d, _ := filepath.Split(filepath.Join(root, rn))
 	if !fs.Exists(d) {
 		if err := os.MkdirAll(d, 0700); err != nil {
 			return errors.Wrap(err, "mk pm dir")