add: generate

3 files changed, 208 insertions, 0 deletions

diff --git a/internal/cli/cli.go b/internal/cli/cli.go
index 6609a7e..fecf64b 100644
--- a/internal/cli/cli.go
+++ b/internal/cli/cli.go
@@ -32,6 +32,7 @@ type model struct {
 	commands []command
 	busy     bool
 	quitting bool
+	events   chan tea.Msg
 
 	width int
 }
@@ -100,6 +101,17 @@ func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.busy = false
 		return m, tea.Println(msg.text)
 
+	case streamMsg:
+		return m, tea.Sequence(tea.Println(msg.text), waitForEvent(m.events))
+
+	case streamDoneMsg:
+		m.busy = false
+		m.events = nil
+		if msg.text == "" {
+			return m, nil
+		}
+		return m, tea.Println(msg.text)
+
 	case spinner.TickMsg:
 		if !m.busy {
 			return m, nil
diff --git a/internal/cli/commands.go b/internal/cli/commands.go
index cf7cc90..f66ff62 100644
--- a/internal/cli/commands.go
+++ b/internal/cli/commands.go
@@ -25,6 +25,11 @@ func defaultCommands() []command {
 			run:  runCheck,
 		},
 		{
+			name: "generate",
+			desc: "Download the server and mods and generate a server directory",
+			run:  runGenerate,
+		},
+		{
 			name: "help",
 			desc: "Show available commands",
 			run: func(m *model) tea.Cmd {
diff --git a/internal/cli/generate.go b/internal/cli/generate.go
new file mode 100644
index 0000000..352b7b4
--- /dev/null
+++ b/internal/cli/generate.go
@@ -0,0 +1,191 @@
+package cli
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	tea "github.com/charmbracelet/bubbletea"
+
+	"github.com/hachem-wtf/benson/internal/config"
+	"github.com/hachem-wtf/benson/internal/modrinth"
+)
+
+var (
+	serverDir = "server"
+	modsDir   = filepath.Join("server", "mods")
+)
+
+var postGenerateDeleteList = []string{
+	"audioplayer_uploads",
+	"config",
+	"cache",
+	"world",
+	"logs",
+	"banned-players.json",
+	"server.properties",
+	"banned-ips.json",
+	"usercache.json",
+	"whitelist.json",
+	"ops.json",
+	"eula.txt",
+}
+
+type streamMsg struct{ text string }
+
+type streamDoneMsg struct{ text string }
+
+func waitForEvent(ch chan tea.Msg) tea.Cmd {
+	return func() tea.Msg {
+		return <-ch
+	}
+}
+
+func runGenerate(m *model) tea.Cmd {
+	m.busy = true
+	ch := make(chan tea.Msg, 256)
+	m.events = ch
+	cfg := m.cfg
+	go generateWorker(cfg, ch)
+	return tea.Batch(m.spin.Tick, waitForEvent(ch))
+}
+
+func generateWorker(cfg *config.Config, ch chan<- tea.Msg) {
+	emit := func(s string) { ch <- streamMsg{s} }
+
+	emit(headingStyle.Render("Generating server for MC " + cfg.MinecraftVersion))
+
+	if err := os.MkdirAll(modsDir, 0o755); err != nil {
+		ch <- streamDoneMsg{errorStyle.Render("Failed to create directories: " + err.Error())}
+		return
+	}
+
+	client := modrinth.NewClient()
+
+	downloaded, failed := 0, 0
+	for _, slug := range cfg.ModrinthMods {
+		versions, err := client.GetVersions(slug)
+		if err != nil {
+			failed++
+			emit("  " + errorStyle.Render("✗ ") + slug + mutedStyle.Render(" — "+err.Error()))
+			continue
+		}
+
+		match := modrinth.CompatibleVersion(versions, cfg.MinecraftVersion, "fabric")
+		if match == nil || len(match.Files) == 0 {
+			failed++
+			emit("  " + errorStyle.Render("✗ ") + slug + mutedStyle.Render(" — no fabric build for MC "+cfg.MinecraftVersion))
+			continue
+		}
+
+		file := match.Files[0]
+		if err := client.Download(file.URL, filepath.Join(modsDir, file.Filename)); err != nil {
+			failed++
+			emit("  " + errorStyle.Render("✗ ") + slug + mutedStyle.Render(" — "+err.Error()))
+			continue
+		}
+
+		downloaded++
+		emit("  " + successStyle.Render("✓ ") + file.Filename)
+	}
+	emit(mutedStyle.Render(fmt.Sprintf("Downloaded %d mods · %d failed", downloaded, failed)))
+
+	emit(headingStyle.Render("Downloading Fabric server"))
+	serverURL := fmt.Sprintf(
+		"https://meta.fabricmc.net/v2/versions/loader/%s/%s/%s/server/jar",
+		cfg.MinecraftVersion, cfg.FabricLoaderVersion, cfg.LoaderMetaVersion,
+	)
+	if err := client.Download(serverURL, filepath.Join(serverDir, "server.jar")); err != nil {
+		ch <- streamDoneMsg{errorStyle.Render("Failed to download Fabric server: " + err.Error())}
+		return
+	}
+	emit("  " + successStyle.Render("✓ ") + "server.jar")
+
+	if err := runServerAutoStop(cfg, emit); err != nil {
+		ch <- streamDoneMsg{errorStyle.Render("Server run failed: " + err.Error())}
+		return
+	}
+
+	removed := deletePostGenerate()
+	emit(mutedStyle.Render(fmt.Sprintf("Removed %d generated items", removed)))
+
+	ch <- streamDoneMsg{successStyle.Render("Generation complete.")}
+}
+
+func runServerAutoStop(cfg *config.Config, emit func(string)) error {
+	eulaPath := filepath.Join(serverDir, "eula.txt")
+	if _, err := os.Stat(eulaPath); os.IsNotExist(err) {
+		if err := os.WriteFile(eulaPath, []byte("eula=true\n"), 0o644); err != nil {
+			return err
+		}
+	}
+
+	java := cfg.JavaPath
+	if java == "" {
+		java = "java"
+	}
+
+	emit(headingStyle.Render("Starting server (auto-stops after loading)"))
+
+	cmd := exec.Command(java, "-jar", "server.jar", "nogui")
+	cmd.Dir = serverDir
+
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	pr, pw, err := os.Pipe()
+	if err != nil {
+		return err
+	}
+	cmd.Stdout = pw
+	cmd.Stderr = pw
+
+	if err := cmd.Start(); err != nil {
+		pw.Close()
+		return err
+	}
+	pw.Close()
+
+	scanner := bufio.NewScanner(pr)
+	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+
+	stopped := false
+	for scanner.Scan() {
+		line := scanner.Text()
+		emit(mutedStyle.Render("  │ " + line))
+
+		if !stopped && strings.Contains(line, "Done") {
+			stopped = true
+			emit(successStyle.Render("  Server loaded, stopping…"))
+			io.WriteString(stdin, "stop\n")
+		}
+	}
+	stdin.Close()
+
+	if err := cmd.Wait(); err != nil && !stopped {
+		return err
+	}
+
+	emit(successStyle.Render("  Server stopped."))
+	return nil
+}
+
+func deletePostGenerate() int {
+	removed := 0
+	for _, item := range postGenerateDeleteList {
+		path := filepath.Join(serverDir, item)
+		if _, err := os.Stat(path); err != nil {
+			continue
+		}
+		if err := os.RemoveAll(path); err == nil {
+			removed++
+		}
+	}
+	return removed
+}