Go rewrite work in progress

cmd/dots/main.go

@@ -0,0 +1,161 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const separator = string(filepath.Separator)
+
+// SourceFile represents a file that is used to compile a configuration file.
+// The source file knows what group it is part of.
+type SourceFile struct {
+	Group    string
+	Path     string
+	Override bool
+}
+
+// ConfigFile represents a configuration file to be installed.
+type ConfigFile struct {
+	Path    string
+	Removed bool
+	Sources []*SourceFile
+}
+
+// Configurations holds a mapping of configuration file destinations mapped to
+// the ConfigFile struct representing that file.
+type Configurations map[string]*ConfigFile
+
+// ResolveSources inserts or updates a Configurations list from a list of
+// configuration sources relative to the source root. Sources not belonging to
+// the specified group will be ignored.
+func ResolveSources(configs Configurations, sources []string, group string) {
+	for _, source := range sources {
+		if !strings.HasPrefix(source, group) {
+			continue
+		}
+
+		destPath := strings.TrimPrefix(source, group+separator)
+
+		sourceFile := &SourceFile{
+			Group: group,
+			Path:  source,
+		}
+
+		// The config file was added in a previous group mapping
+		if file, ok := configs[destPath]; ok {
+			file.Sources = append(file.Sources, sourceFile)
+			continue
+		}
+
+		configs[destPath] = &ConfigFile{
+			Path:    destPath,
+			Sources: []SourceFile{sourceFile},
+		}
+	}
+}
+
+// ResolveOverrides scans a Configurations list for config files that have
+// associated override files. The override files will be removed as individual
+// configurations and their sources will be inserted into config file they are
+// associated to.
+func ResolveOverrides(configs Configurations, overrideSuffix string) {
+	for path, config := range configs {
+		if strings.HasSuffix(path, overrideSuffix) {
+			continue
+		}
+
+		overridePath := path + overrideSuffix
+		overrideConfig, exists := configs[overridePath]
+
+		if !exists {
+			continue
+		}
+
+		for _, source := range overrideConfig.Sources {
+			source.Override = true
+		}
+
+		config.Sources = append(config.Sources, overrideConfig.Sources...)
+		delete(config, overridePath)
+	}
+}
+
+// ResolveRemoved inserts entries into a Configurations list for files that
+// previously were installed but are no longer present to be installed.
+func ResolveRemoved(configs Configurations, oldConfigs []string) {
+	for _, oldConfig := range oldConfigs {
+		if _, ok := configs[oldConfig]; ok {
+			continue
+		}
+
+		configs[oldConfig] = &ConfigFile{
+			Path:    oldConfig,
+			Removed: true,
+		}
+	}
+}
+
+// ResolveScripts herp derp
+func ResolveScripts(configs Configurations) {
+
+}
+
+func main() {
+	// TODO: Verify config file exists
+	configPath := "/home/evan/.local/etc"
+
+	var sources []string
+
+	walker := func(path string, info os.FileInfo, err error) error {
+		if err != nil || info.IsDir() {
+			return nil
+		}
+
+		srcPath := strings.TrimPrefix(path, configPath+separator)
+		sources = append(sources, srcPath)
+
+		return nil
+	}
+
+	filepath.Walk(configPath, walker)
+
+	configs := Configurations{}
+
+	// TODO: Add group validation: ensure mutual exlcusion and files exist.
+	//       Could just reduce the groups list and produce warnings for bad
+	//       groups.
+	groups := []string{
+		"base",
+		"machines/desktop",
+	}
+
+	for _, group := range groups {
+		ResolveSources(configs, sources, group)
+	}
+
+	for _, config := range configs {
+		fmt.Printf("%#v\n", config)
+	}
+
+	// TODO: Output writer that looks somthing like
+	//
+	// source:  /home/.local/etc
+	// install: /home/.config
+	//
+	// [=> base ]    bash/bashrc
+	// [=> composed] bash/environment
+	//  -> composing from base and machines/desktop groups
+	// [=> removed ] bash/bad-filemulti
+	// [=> compiled] bash/complex
+	//  -> ignoring configs in base and common/work due to override
+	//  -> override file present in common/work-vm
+	//  -> composing from machines/crunchydev (spliced at common/work-vm:22)
+	//
+	// [=> install script] base/bash.install
+	//  -> triggered by base/bash/bashrc
+	//  -> triggered by base/bash/environment
+
+}