feat: use XDG specification (#23)

* feat: default database to the XDG data dir

* docs(readme): update data section

README.md

@@ -120,7 +120,7 @@ An example configuration file is provided in [`example.config.toml`](./example.c
 
 ## Data
 
-The game data is stored in a SQLite database. By default, the database is stored in the working directory as `tetrigo.db`. You can specify a different file using the `--db` flag.
+The game data is stored in a SQLite database. By default, the database is stored in `./tetrigo/tetrigo.db` within the devices XDG data (or equivalent) directory. The [adrg/xdg](https://github.com/adrg/xdg) defines values `XDG_DATA_DIRS` for various operating systems (eg. on macOS if the `/Library/Application Support` directory exists it will be stored there, otherwise in `~/.local/share`). You can specify a different file path using the `--db` flag.
 
 ```bash
 ./tetrigo --db=/path/to/data.db

cmd/tetrigo/main.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"log"
+
+	"github.com/adrg/xdg"
 	"github.com/alecthomas/kong"
 )
 
@@ -14,7 +17,7 @@ type CLI struct {
 
 type GlobalVars struct {
 	Config string `help:"Path to config file" default:"config.toml" type:"path"`
-	DB     string `help:"Path to database file" default:"tetrigo.db"`
+	DB     string `help:"Path to database file. Empty value will use XDG data directory." default:""`
 }
 
 func main() {
@@ -24,6 +27,15 @@ func main() {
 		kong.Description("A tetris TUI written in Go"),
 		kong.UsageOnError(),
 	)
+
+	if cli.GlobalVars.DB == "" {
+		var err error
+		cli.GlobalVars.DB, err = xdg.DataFile("./tetrigo/tetrigo.db")
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
 	// Call the Run() method of the selected parsed command.
 	err := ctx.Run(&cli.GlobalVars)
 	ctx.FatalIfErrorf(err)

go.mod

@@ -4,6 +4,7 @@ go 1.23.0
 
 require (
 	github.com/BurntSushi/toml v1.3.2
+	github.com/adrg/xdg v0.5.3
 	github.com/alecthomas/kong v0.8.1
 	github.com/charmbracelet/bubbles v0.18.0
 	github.com/charmbracelet/bubbletea v0.25.0
@@ -29,7 +30,7 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	golang.org/x/sync v0.1.0 // indirect
-	golang.org/x/sys v0.12.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
 	golang.org/x/term v0.6.0 // indirect
 	golang.org/x/text v0.3.8 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/BurntSushi/toml v1.3.2 h1:o7IhLm0Msx3BaB+n3Ag7L8EVlByGnpq14C4YWiu/gL8=
 github.com/BurntSushi/toml v1.3.2/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
+github.com/adrg/xdg v0.5.3 h1:xRnxJXne7+oWDatRhR1JLnvuccuIeCoBu2rtuLqQB78=
+github.com/adrg/xdg v0.5.3/go.mod h1:nlTsY+NNiCBGCK2tpm09vRqfVzrc2fLmXGpBLF0zlTQ=
 github.com/alecthomas/assert/v2 v2.1.0 h1:tbredtNcQnoSd3QBhQWI7QZ3XHOVkw1Moklp2ojoH/0=
 github.com/alecthomas/assert/v2 v2.1.0/go.mod h1:b/+1DI2Q6NckYi+3mXyH3wFb8qG37K/DuK80n7WefXA=
 github.com/alecthomas/kong v0.8.1 h1:acZdn3m4lLRobeh3Zi2S2EpnXTd1mOL6U7xVml+vfkY=
@@ -55,8 +57,8 @@ golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
-golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
+golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.6.0 h1:clScbb1cHjoCkyRbWwBEUZ5H/tIFu5TAXIqaZD0Gcjw=
 golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=