feat: add .goscaf.yaml support for persistent global and local defaults

CONTRIBUTING.md

@@ -29,11 +29,17 @@ First off, thank you for considering contributing to `goscaf`! It's people like
 4. Build the project: `make build`.
 
 ## Project Structure
-- `main.go`: Entry point.
+- `main.go`: Entry point — delegates immediately to `cmd.Execute()`.
 - `cmd/`: CLI commands (Cobra-based).
-- `internal/`: Core logic and templates.
-    - `internal/generator/`: Logic for generating files.
-    - `internal/templates/`: Project boilerplates.
+    - `cmd/root.go`: Root command and banner.
+    - `cmd/init.go`: `goscaf init` — collects config and drives the generator.
+    - `cmd/add.go`: `goscaf add` — adds a new service scaffold to an existing project.
+- `internal/`: Core logic — not importable by external packages.
+    - `internal/config/`: `ProjectConfig` struct and typed constants for framework, logger, and database choices.
+    - `internal/userconfig/`: Loads and merges `~/.goscaf.yaml` (global) and `./.goscaf.yaml` (local) defaults.
+    - `internal/prompt/`: Interactive survey prompts; accepts a `UserConfig` to pre-fill defaults.
+    - `internal/generator/`: Orchestrates file writes for `goscaf init` and `goscaf add`.
+    - `internal/templates/`: Go `text/template` strings for every generated file.
 
 ## Style Guide
 - We follow standard Go idioms.

README.md

@@ -117,6 +117,105 @@ goscaf init my-api --framework fiber --logger zap --redis --kafka --docker
 
 ---
 
+## Config file (.goscaf.yaml)
+
+Tired of answering the same prompts every time? Save your preferences once in a `.goscaf.yaml` file and `goscaf` will pre-fill every prompt with your defaults. You can still change any value at the prompt — the config just saves you the typing.
+
+### Two scopes, same format
+
+| File | Scope | Who should set it |
+|---|---|---|
+| `~/.goscaf.yaml` | Global — applies to all projects on this machine | Individual developers |
+| `./.goscaf.yaml` | Local — applies only to the current directory | Teams (commit to the repo) |
+
+When both files exist, **local values win over global**. CLI flags always win over both. The full priority chain is:
+
+```
+hardcoded defaults < ~/.goscaf.yaml < ./.goscaf.yaml < CLI flags
+```
+
+### All supported fields
+
+```yaml
+# .goscaf.yaml
+
+# Module prefix — goscaf appends /<project-name> automatically.
+# Example: "github.com/your-org" produces "github.com/your-org/my-api"
+module_prefix: github.com/your-org
+
+# Go toolchain version to write into go.mod
+go_version: "1.25.0"
+
+# HTTP framework: gin | fiber | chi | echo | gorilla | none
+framework: gin
+
+# Structured logger: slog | zerolog | zap
+logger: slog
+
+# Database driver: none | postgres | mysql | sqlite | mongo | gorm
+db: none
+
+# Optional infrastructure clients
+viper:    true
+redis:    false
+kafka:    false
+nats:     false
+
+# DevOps scaffolding
+docker:   true
+makefile: true
+github:   true
+lint:     true
+swagger:  false
+git_repo: false
+```
+
+Any field you omit falls back to the next level in the priority chain — you only need to set what you actually want to override.
+
+### Common setups
+
+**Personal global config** — sets your usual module prefix and preferred logger, nothing else:
+
+```yaml
+# ~/.goscaf.yaml
+module_prefix: github.com/john-doe
+logger: zap
+go_version: "1.25.0"
+```
+
+**Team repo config** — standardises the stack across all services; commit this file so every engineer gets the same defaults:
+
+```yaml
+# .goscaf.yaml  (committed to the monorepo root)
+module_prefix: github.com/acme-corp
+framework: chi
+logger: zerolog
+viper: true
+docker: true
+makefile: true
+github: true
+lint: true
+swagger: false
+```
+
+**Override a single field at the CLI** — team config says `framework: chi`, but you need fiber just this once:
+
+```bash
+goscaf init payments-service --framework fiber
+```
+
+The rest of the fields still come from `.goscaf.yaml`; only `framework` is overridden.
+
+### What happens in each mode
+
+| Mode | Config file applied? |
+|---|---|
+| Interactive (`goscaf init <name>`) | Yes — pre-fills prompt defaults |
+| Flag-driven (`--framework`, `--logger`, …) | Yes — fills any field not covered by a flag |
+| Defaults (`--defaults`) | No — hardcoded defaults only, config ignored |
+
+---
+
 ## Flags
 
 | Flag            | Default   | Description                                       |

cmd/init.go

@@ -11,6 +11,7 @@ import (
 	"github.com/iyashjayesh/goscaf/internal/config"
 	"github.com/iyashjayesh/goscaf/internal/generator"
 	"github.com/iyashjayesh/goscaf/internal/prompt"
+	"github.com/iyashjayesh/goscaf/internal/userconfig"
 )
 
 var (
@@ -45,6 +46,13 @@ var initCmd = &cobra.Command{
 	RunE: func(cmd *cobra.Command, args []string) error {
 		projectName := args[0]
 
+		// Load .goscaf.yaml (global then local, local wins). A missing file is
+		// not an error — uc will be nil and prompts fall back to hardcoded defaults.
+		uc, err := userconfig.Load()
+		if err != nil {
+			color.Yellow("  ⚠ could not read .goscaf.yaml: %v", err)
+		}
+
 		var cfg *config.ProjectConfig
 
 		if flagDefaults {
@@ -70,7 +78,8 @@ var initCmd = &cobra.Command{
 		} else if cmd.Flags().Changed("framework") || cmd.Flags().Changed("module") ||
 			cmd.Flags().Changed("go-version") || cmd.Flags().Changed("logger") ||
 			cmd.Flags().Changed("db") {
-			// Flags provided - use flag-driven mode (merge with defaults)
+			// Flags provided — start from flag values, then fill in any field the
+			// user did NOT explicitly set from .goscaf.yaml (flags always win).
 			cfg = &config.ProjectConfig{
 				ProjectName: projectName,
 				ModuleName:  flagModule,
@@ -90,14 +99,21 @@ var initCmd = &cobra.Command{
 				GitRepo:     flagGitRepo,
 			}
 			if cfg.ModuleName == "" {
-				cfg.ModuleName = fmt.Sprintf("github.com/your-org/%s", projectName)
+				if uc != nil && uc.ModulePrefix != "" {
+					cfg.ModuleName = uc.ModulePrefix + "/" + projectName
+				} else {
+					cfg.ModuleName = fmt.Sprintf("github.com/your-org/%s", projectName)
+				}
+			}
+			if uc != nil {
+				applyUserConfig(cmd, cfg, uc)
 			}
 		} else {
-			// Interactive mode
-			var err error
-			cfg, err = prompt.Run(projectName)
-			if err != nil {
-				return fmt.Errorf("prompt failed: %w", err)
+			// Interactive mode — userconfig pre-fills prompt defaults.
+			var promptErr error
+			cfg, promptErr = prompt.Run(projectName, uc)
+			if promptErr != nil {
+				return fmt.Errorf("prompt failed: %w", promptErr)
 			}
 		}
 
@@ -148,6 +164,53 @@ var initCmd = &cobra.Command{
 	},
 }
 
+// applyUserConfig fills cfg fields from uc for any flag the user did not
+// explicitly pass on the command line. CLI flags always take precedence.
+func applyUserConfig(cmd *cobra.Command, cfg *config.ProjectConfig, uc *userconfig.UserConfig) {
+	if !cmd.Flags().Changed("go-version") && uc.GoVersion != "" {
+		cfg.GoVersion = uc.GoVersion
+	}
+	if !cmd.Flags().Changed("framework") && uc.Framework != "" {
+		cfg.Framework = config.Framework(uc.Framework)
+	}
+	if !cmd.Flags().Changed("logger") && uc.Logger != "" {
+		cfg.Logger = config.Logger(uc.Logger)
+	}
+	if !cmd.Flags().Changed("db") && uc.DB != "" {
+		cfg.Database = config.Database(uc.DB)
+	}
+	if !cmd.Flags().Changed("viper") && uc.Viper != nil {
+		cfg.Viper = *uc.Viper
+	}
+	if !cmd.Flags().Changed("redis") && uc.Redis != nil {
+		cfg.Redis = *uc.Redis
+	}
+	if !cmd.Flags().Changed("kafka") && uc.Kafka != nil {
+		cfg.Kafka = *uc.Kafka
+	}
+	if !cmd.Flags().Changed("nats") && uc.NATS != nil {
+		cfg.NATS = *uc.NATS
+	}
+	if !cmd.Flags().Changed("docker") && uc.Docker != nil {
+		cfg.Docker = *uc.Docker
+	}
+	if !cmd.Flags().Changed("makefile") && uc.Makefile != nil {
+		cfg.Makefile = *uc.Makefile
+	}
+	if !cmd.Flags().Changed("github") && uc.GitHub != nil {
+		cfg.GitHub = *uc.GitHub
+	}
+	if !cmd.Flags().Changed("lint") && uc.Lint != nil {
+		cfg.Lint = *uc.Lint
+	}
+	if !cmd.Flags().Changed("swagger") && uc.Swagger != nil {
+		cfg.Swagger = *uc.Swagger
+	}
+	if !cmd.Flags().Changed("git-repo") && uc.GitRepo != nil {
+		cfg.GitRepo = *uc.GitRepo
+	}
+}
+
 func init() {
 	rootCmd.AddCommand(initCmd)
 

go.mod

@@ -18,4 +18,5 @@ require (
 	golang.org/x/sys v0.42.0 // indirect
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 // indirect
 	golang.org/x/text v0.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -68,3 +68,5 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=