From 84961bda58bfaa84846abb5999138eebfec6bf0e Mon Sep 17 00:00:00 2001
From: Noah <noah.matthew@metzger.cc>
Date: Wed, 27 Mar 2024 11:25:55 -0500
Subject: [PATCH] Switch main configuration language to Lua (fix #28)

---
 .gitignore |  1 +
 config.go  | 81 ++++++++++++++++++++++++++++++++++++++++--------------
 go.mod     | 10 +++++--
 go.sum     |  2 ++
 4 files changed, 71 insertions(+), 23 deletions(-)

diff --git a/.gitignore b/.gitignore
index c5dfc4a..8c58e69 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 lapisdeploy
 config.json
+config.lua
 sites/
diff --git a/config.go b/config.go
index b4ce5bb..9af80f7 100644
--- a/config.go
+++ b/config.go
@@ -2,14 +2,14 @@
 package main
 
 import (
-	"encoding/json"
-	"log"
-	"os"
+	"errors"
+
+	"github.com/yuin/gopher-lua"
 )
 
 // Configuration stores information retrieved from a configuration file
 type Configuration struct {
-	port      int
+	port      int64
 	sites_dir string
 	matrix    struct {
 		homeserver string
@@ -19,23 +19,64 @@ type Configuration struct {
 	}
 }
 
+// getStringFromTable retrieves a string from a table on the lua stack using the key passed in.
+func getStringFromTable(L *lua.LState, lobj lua.LValue, key string, out *string) error {
+	lv := L.GetTable(lobj, lua.LString(key))
+	if text, ok := lv.(lua.LString); ok {
+		*out = string(text)
+	} else {
+		return errors.New("Failed to get string from table using key '" + key + "'")
+	}
+	return nil
+}
+
+// getIntFromTable retrieves an integer from a table on the Lua stack using the key passed in.
+func getIntFromTable(L *lua.LState, lobj lua.LValue, key string, out *int64) error {
+	lv := L.GetTable(lobj, lua.LString(key))
+	if int, ok := lv.(lua.LNumber); ok {
+		*out = int64(int)
+	} else {
+		return errors.New("Failed to get integer from table using key '" + key + "'")
+	}
+	return nil
+}
+
+// getTableFromTable retrieves a nested table from the Lua stack using the key passed in.
+func getTableFromTable(L *lua.LState, lobj lua.LValue, key string, out *lua.LValue) {
+	*out = L.GetTable(lobj, lua.LString(key))
+
+}
+
 // parseConfig parses the JSON configuration file at 'path' and stores the contents in 'config'
 func parseConfig(path string, config *Configuration) {
-	file, _ := os.Open(path)
-	var data map[string]interface{}
-	err := json.NewDecoder(file).Decode(&data)
-	if err != nil {
-		log.Panic("Failed to parse config: ", err)
-	}
-	file.Close()
-	// Main configuration
-	config.port = int(data["port"].(float64)) // this conversion makes no sense
-	config.sites_dir = data["sites_dir"].(string)
+	// Lua state setup
+	L := lua.NewState()
+	defer L.Close()
 
-	// Matrix configuration
-	matrix := data["matrix"].(map[string]interface{})
-	config.matrix.homeserver = matrix["homeserver"].(string)
-	config.matrix.username = matrix["username"].(string)
-	config.matrix.password = matrix["password"].(string)
-	config.matrix.room_id = matrix["room_id"].(string)
+	L.DoFile(path)
+	table := L.Get(-1) // Get the table returned by the config file
+
+	// Main config
+	if err := getStringFromTable(L, table, "sites_dir", &config.sites_dir); err != nil {
+		panic(err)
+	}
+	if err := getIntFromTable(L, table, "port", &config.port); err != nil {
+		panic(err)
+	}
+
+	// Matrix config
+	var matrix lua.LValue
+	getTableFromTable(L, table, "matrix", &matrix)
+	if err := getStringFromTable(L, matrix, "homeserver", &config.matrix.homeserver); err != nil {
+		panic(err)
+	}
+	if err := getStringFromTable(L, matrix, "username", &config.matrix.username); err != nil {
+		panic(err)
+	}
+	if err := getStringFromTable(L, matrix, "password", &config.matrix.password); err != nil {
+		panic(err)
+	}
+	if err := getStringFromTable(L, matrix, "room_id", &config.matrix.room_id); err != nil {
+		panic(err)
+	}
 }
diff --git a/go.mod b/go.mod
index ee697cb..d2f839a 100644
--- a/go.mod
+++ b/go.mod
@@ -3,8 +3,13 @@ module code.retroedge.tech/noah/lapisdeploy
 go 1.22.0
 
 require (
-	github.com/akamensky/argparse v1.4.0 // indirect
-	github.com/gogs/git-module v1.8.3 // indirect
+	github.com/akamensky/argparse v1.4.0
+	github.com/gogs/git-module v1.8.3
+	github.com/yuin/gopher-lua v1.1.1
+	maunium.net/go/mautrix v0.17.0
+)
+
+require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mcuadros/go-version v0.0.0-20190308113854-92cdf37c5b75 // indirect
@@ -22,5 +27,4 @@ require (
 	golang.org/x/sys v0.18.0 // indirect
 	golang.org/x/tools v0.19.0 // indirect
 	maunium.net/go/maulogger/v2 v2.4.1 // indirect
-	maunium.net/go/mautrix v0.17.0 // indirect
 )
diff --git a/go.sum b/go.sum
index d4869ba..d6a6ff6 100644
--- a/go.sum
+++ b/go.sum
@@ -37,6 +37,8 @@ github.com/tidwall/sjson v1.2.5 h1:kLy8mja+1c9jlljvWTlSazM7cKDRfJuR/bOJhcY5NcY=
 github.com/tidwall/sjson v1.2.5/go.mod h1:Fvgq9kS/6ociJEDnK0Fk1cpYF4FIW6ZF7LAe+6jwd28=
 github.com/yuin/goldmark v1.6.0 h1:boZcn2GTjpsynOsC0iJHnBWa4Bi0qzfJjthwauItG68=
 github.com/yuin/goldmark v1.6.0/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
+github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
 go.mau.fi/util v0.4.0 h1:S2X3qU4pUcb/vxBRfAuZjbrR9xVMAXSjQojNBLPBbhs=
 go.mau.fi/util v0.4.0/go.mod h1:leeiHtgVBuN+W9aDii3deAXnfC563iN3WK6BF8/AjNw=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=