*: Reorganize code

macro/macro.go

@@ -0,0 +1,209 @@
+package macro
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"strings"
+	"text/template"
+
+	"github.com/kovetskiy/mark/includes"
+	"github.com/reconquest/karma-go"
+	"github.com/reconquest/pkg/log"
+	"github.com/reconquest/regexputil-go"
+	"gopkg.in/yaml.v3"
+)
+
+var reMacroDirective = regexp.MustCompile(
+	// <!-- Macro: <regexp>
+	//      Template: <template path>
+	//      <optional yaml data> -->
+
+	`(?s)` + // dot capture newlines
+		/**/ `<!--\s*Macro:\s*(?P<expr>[^\n]+)\n` +
+		/*    */ `\s*Template:\s*(?P<template>.+?)\s*` +
+		/*   */ `(?P<config>\n.*?)?-->`,
+)
+
+type Macro struct {
+	Regexp   *regexp.Regexp
+	Template *template.Template
+	Config   string
+}
+
+func (macro *Macro) Apply(
+	content []byte,
+) ([]byte, error) {
+	var err error
+
+	content = macro.Regexp.ReplaceAllFunc(
+		content,
+		func(match []byte) []byte {
+			config := map[string]interface{}{}
+
+			err = yaml.Unmarshal([]byte(macro.Config), &config)
+			if err != nil {
+				err = karma.Format(
+					err,
+					"unable to unmarshal macros config template",
+				)
+			}
+
+			var buffer bytes.Buffer
+
+			err = macro.Template.Execute(&buffer, macro.configure(
+				config,
+				macro.Regexp.FindSubmatch(match),
+			))
+			if err != nil {
+				err = karma.Format(
+					err,
+					"unable to execute macros template",
+				)
+			}
+
+			return buffer.Bytes()
+		},
+	)
+
+	return content, err
+}
+
+func (macro *Macro) configure(node interface{}, groups [][]byte) interface{} {
+	switch node := node.(type) {
+	case map[interface{}]interface{}:
+		for key, value := range node {
+			node[key] = macro.configure(value, groups)
+		}
+
+		return node
+	case map[string]interface{}:
+		for key, value := range node {
+			node[key] = macro.configure(value, groups)
+		}
+
+		return node
+	case []interface{}:
+		for key, value := range node {
+			node[key] = macro.configure(value, groups)
+		}
+
+		return node
+	case string:
+		for i, group := range groups {
+			node = strings.ReplaceAll(
+				node,
+				fmt.Sprintf("${%d}", i),
+				string(group),
+			)
+		}
+
+		return node
+	}
+
+	return node
+}
+
+func ExtractMacros(
+	base string,
+	includePath string,
+	contents []byte,
+	templates *template.Template,
+) ([]Macro, []byte, error) {
+	var err error
+
+	var macros []Macro
+
+	contents = reMacroDirective.ReplaceAllFunc(
+		contents,
+		func(spec []byte) []byte {
+			if err != nil {
+				return spec
+			}
+
+			groups := reMacroDirective.FindStringSubmatch(string(spec))
+
+			var (
+				expr     = regexputil.Subexp(reMacroDirective, groups, "expr")
+				template = regexputil.Subexp(
+					reMacroDirective,
+					groups,
+					"template",
+				)
+				config = regexputil.Subexp(reMacroDirective, groups, "config")
+			)
+
+			var macro Macro
+
+			if strings.HasPrefix(template, "#") {
+				cfg := map[string]interface{}{}
+
+				err = yaml.Unmarshal([]byte(config), &cfg)
+				if err != nil {
+					err = karma.Format(
+						err,
+						"unable to unmarshal macros config template",
+					)
+
+					return nil
+				}
+
+				body, ok := cfg[template[1:]].(string)
+				if !ok {
+					err = fmt.Errorf(
+						"the template config doesn't have '%s' field",
+						template[1:],
+					)
+
+					return nil
+				}
+
+				macro.Template, err = templates.New(template).Parse(body)
+				if err != nil {
+					err = karma.Format(
+						err,
+						"unable to parse template",
+					)
+
+					return nil
+				}
+			} else {
+				macro.Template, err = includes.LoadTemplate(base, includePath, template, "{{", "}}", templates)
+				if err != nil {
+					err = karma.Format(err, "unable to load template")
+
+					return nil
+				}
+			}
+
+			facts := karma.
+				Describe("template", template).
+				Describe("expr", expr)
+
+			macro.Regexp, err = regexp.Compile(expr)
+			if err != nil {
+				err = facts.
+					Format(
+						err,
+						"unable to compile macros regexp",
+					)
+
+				return nil
+			}
+
+			macro.Config = config
+
+			log.Tracef(
+				facts.Describe("config", macro.Config),
+				"loaded macro %q",
+				expr,
+			)
+
+			macros = append(macros, macro)
+
+			return []byte{}
+		},
+	)
+
+	return macros, contents, err
+}