adding init program

cmd/streamdeck-init/yaml.go

@@ -0,0 +1,148 @@
+// yaml.go — Appends key entries to config.yaml without destroying comments.
+//
+// ## Why raw text append instead of yaml.Marshal?
+//
+// yaml.v3's Marshal destroys comments, reorders map keys, and normalises
+// formatting. Users keep the default config's comments (key layout diagram,
+// examples, etc.), so we must preserve them. The approach:
+//
+//   - Parse config.yaml with config.Load() for DATA (which keys exist, icons_dir, etc.)
+//   - Write new keys by appending raw YAML text to the end of the file
+//
+// This works because keys: is always the last top-level block in config.yaml,
+// and YAML maps are unordered, so appending a new 2-space-indented key entry
+// to the end of the file is valid.
+//
+// ## Three cases handled by appendKeyToConfig
+//
+// Case A: "keys: {}" — the empty map literal from the default config generator.
+//
+//	Replace {} with a newline, then insert the key block. This is the most
+//	common case on a fresh install.
+//
+// Case B: "keys:" with existing children — the normal case after keys exist.
+//
+//	Append the new key block to the end of the file. It lands inside the
+//	keys: block because it's indented with 2 spaces.
+//
+// Case C: no "keys:" block at all — a malformed or minimal config.
+//
+//	Append "keys:\n" then the key block.
+//
+// ## Expanding
+//
+// To support toggle keys (icon_true/icon_false + poll block), add those fields
+// to keyEntry and extend renderKeySnippet() to emit the extra YAML lines.
+//
+// To support deleting or editing existing keys, you'd need a different strategy
+// (e.g. yaml.v3 node-level manipulation). That's not in scope for the current
+// append-only tool.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+	"sort"
+	"strings"
+)
+
+// keyEntry holds the data collected from the TUI forms, ready to be rendered
+// as a YAML snippet and appended to config.yaml.
+//
+// Two mutually exclusive modes:
+//   - Module key: Module + Function + Params are set, Command is empty
+//   - Command key: Command is set, Module/Function/Params are empty
+type keyEntry struct {
+	Index    int               // key slot (0-31)
+	Icon     string            // icon filename relative to icons_dir
+	Module   string            // module name from modules.yaml (e.g. "slack")
+	Function string            // function name within the module (e.g. "set_status")
+	Params   map[string]string // param overrides (merged with module defaults at runtime)
+	Command  string            // raw shell command (non-module keys only)
+}
+
+// appendKeyToConfig reads config.yaml, appends a key entry as raw YAML text,
+// and writes the file back. Preserves all existing content including comments.
+func appendKeyToConfig(path string, entry keyEntry) error {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("read config: %w", err)
+	}
+
+	content := string(data)
+	snippet := renderKeySnippet(entry)
+
+	// Case A: keys: {} — empty map literal from the default config generator.
+	// Replace the {} with a newline so the snippet becomes the first child.
+	emptyKeys := regexp.MustCompile(`(?m)^keys:\s*\{\}\s*$`)
+	if emptyKeys.MatchString(content) {
+		content = emptyKeys.ReplaceAllString(content, "keys:\n"+snippet)
+		return os.WriteFile(path, []byte(content), 0644)
+	}
+
+	// Case B: keys: exists with children — append snippet to end of file.
+	// The 2-space indent on the snippet places it inside the keys: block.
+	hasKeys := regexp.MustCompile(`(?m)^keys:\s*$`)
+	if hasKeys.MatchString(content) {
+		if !strings.HasSuffix(content, "\n") {
+			content += "\n"
+		}
+		content += snippet
+		return os.WriteFile(path, []byte(content), 0644)
+	}
+
+	// Case C: no keys: block at all — append both the block header and snippet.
+	if !strings.HasSuffix(content, "\n") {
+		content += "\n"
+	}
+	content += "\nkeys:\n" + snippet
+	return os.WriteFile(path, []byte(content), 0644)
+}
+
+// renderKeySnippet formats a keyEntry as an indented YAML block (2-space indent
+// for the key index, 4-space for fields, 6-space for params).
+//
+// Module key output:
+//
+//	  3:
+//	    icon: status.png
+//	    module: slack
+//	    function: set_status
+//	    params:
+//	      emoji: ":brb:"
+//	      text: "BRB"
+//
+// Command key output:
+//
+//	  3:
+//	    icon: firefox.png
+//	    command: "open -a Firefox"
+func renderKeySnippet(e keyEntry) string {
+	var b strings.Builder
+
+	fmt.Fprintf(&b, "  %d:\n", e.Index)
+	fmt.Fprintf(&b, "    icon: %s\n", e.Icon)
+
+	if e.Module != "" {
+		fmt.Fprintf(&b, "    module: %s\n", e.Module)
+		fmt.Fprintf(&b, "    function: %s\n", e.Function)
+		if len(e.Params) > 0 {
+			b.WriteString("    params:\n")
+			// Sort param keys for deterministic, diffable output.
+			keys := make([]string, 0, len(e.Params))
+			for k := range e.Params {
+				keys = append(keys, k)
+			}
+			sort.Strings(keys)
+			for _, k := range keys {
+				fmt.Fprintf(&b, "      %s: \"%s\"\n", k, e.Params[k])
+			}
+		}
+	} else {
+		fmt.Fprintf(&b, "    command: \"%s\"\n", e.Command)
+	}
+
+	return b.String()
+}