refactor the whole structure

.golangci.yml

@@ -0,0 +1,24 @@
+run:
+  concurrency: 2
+  timeout: 5m
+
+linter-settings:
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+
+linters:
+  enable:
+    - golint
+    - goconst
+    - gofmt
+    - goimports
+    - misspell
+    - unparam
+
+issues:
+  exclude-use-default: false
+  exclude-rules:
+    - path: _test.go
+      linters:
+        - errcheck

.travis.yml

@@ -6,7 +6,11 @@ language: go
 go:
   - "1.13.x"
 
+before_install:
+  - curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.24.0
+
 script:
+  - golangci-lint run
   - ./go.test.sh
 
 after_success:

config/config.go

@@ -1,62 +1,5 @@
 package config
 
-var (
-	// Debug debug mode
-	Debug bool
-	// Version show version
-	Version bool
-	// InfoOnly Information only mode
-	InfoOnly bool
-	// Cookie http cookies
-	Cookie string
-	// Playlist download playlist
-	Playlist bool
-	// Refer use specified Referrer
-	Refer string
-	// Stream select specified stream to download
-	Stream string
-	// OutputPath output file path
-	OutputPath string
-	// OutputName output file name
-	OutputName string
-	// ExtractedData print extracted data
-	ExtractedData bool
-	// ChunkSizeMB HTTP chunk size for downloading (in MB)
-	ChunkSizeMB int
-	// UseAria2RPC Use Aria2 RPC to download
-	UseAria2RPC bool
-	// Aria2Token Aria2 RPC Token
-	Aria2Token string
-	// Aria2Addr Aria2 Address (default "localhost:6800")
-	Aria2Addr string
-	// Aria2Method Aria2 Method (default "http")
-	Aria2Method string
-	// ThreadNumber The number of download thread (only works for multiple-parts video)
-	ThreadNumber int
-	// File URLs file path
-	File string
-	// ItemStart Define the starting item of a playlist or a file input
-	ItemStart int
-	// ItemEnd Define the ending item of a playlist or a file input
-	ItemEnd int
-	// Items Define wanted items from a file or playlist. Separated by commas like: 1,5,6,8-10
-	Items string
-	// File name of each bilibili episode doesn't include the playlist title
-	EpisodeTitleOnly bool
-	// Caption download captions
-	Caption bool
-	// YoukuCcode youku ccode
-	YoukuCcode string
-	// YoukuCkey youku ckey
-	YoukuCkey string
-	// YoukuPassword youku password
-	YoukuPassword string
-	// RetryTimes how many times to retry when the download failed
-	RetryTimes int
-
-	MultiThread bool
-)
-
 // FakeHeaders fake http headers
 var FakeHeaders = map[string]string{
 	"Accept":          "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",