package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/gocolly/colly"
)

const (
	DocsUrl  = "http://127.0.0.1:4567/docs/"
	CacheDir = "cache/"
)

func commentize(text string) string {
	text = text[strings.Index(text, ") -")+len(") -"):]
	text = strings.ReplaceAll(text, "\n", "\n    // ")
	return text
}

func main() {
	c := colly.NewCollector()

	// Find and visit all doc pages
	c.OnHTML("a[href]", func(e *colly.HTMLElement) {
		url := e.Attr("href")
		if !strings.HasPrefix(url, "/docs/builders") {
			return
		}
		e.Request.Visit(url)
	})
	for _, required := range []bool{true, false} {
		required := required
		sel := "#required- + ul a[name]"
		if !required {
			sel = "#optional- + ul a[name]"
		}
		c.OnHTML(sel, func(e *colly.HTMLElement) {

			name := e.Attr("name")

			builder := e.Request.URL.Path[strings.Index(e.Request.URL.Path, "/builders/")+len("/builders/"):]
			builder = strings.TrimSuffix(builder, ".html")

			fieldDoc := e.DOM.Parent()
			text := fieldDoc.Text()

			builderPath := strings.Split(builder, "-")[0]
			if name == "vpc_filter" {
				fmt.Printf("required: %25s builderPath: %20s text: %20s\n", name, builderPath, text)
			}

			err := filepath.Walk("./builder/"+builderPath, func(path string, info os.FileInfo, err error) error {
				if err != nil || info.IsDir() || filepath.Ext(path) != ".go" {
					return nil
				}
				body, err := ioutil.ReadFile(path)
				if err != nil {
					panic(err)
				}
				regex := regexp.MustCompile(fmt.Sprintf(`(\n\s+//.*)*\n+(\s*)([A-Z].*mapstructure:"%s")(\s+required:"%t")?(.*)`, name, required))

				replaced := regex.ReplaceAll(body, []byte(fmt.Sprintf("\n$2//%s\n"+`$2$3 required:"%t"$5`, commentize(text), required)))

				if string(replaced) == string(body) {
					return nil
				}

				err = ioutil.WriteFile(path, replaced, 0)
				if err != nil {
					panic(err)
				}

				return nil
			})
			if err != nil {
				panic(err)
			}
		})
	}

	c.CacheDir = CacheDir

	c.Visit(DocsUrl)
}