package main

import (
	"fmt"
	"log"
	"net/url"
	"os"
	"path/filepath"

	"go.alanpearce.eu/gomponents"
	"gopkg.in/yaml.v3"
)

type URL struct {
	*url.URL
}

func (u *URL) UnmarshalYAML(value *yaml.Node) (err error) {
	var s string
	if err := value.Decode(&s); err != nil {
		return err
	}
	u.URL, err = url.Parse(s)
	return err
}

type Config struct {
	Title    string
	Domain   URL
	Forge    URL
	Menu     []*MenuLink
	Packages []string
}

type MenuLink struct {
	Name string
	URL  URL
}

func must[T any](t T, err error) T {
	if err != nil {
		panic(err)
	}
	return t
}

func fatal(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

func importString(config *Config, pkg string) string {
	return fmt.Sprintf("%s git %s",
		config.Domain.JoinPath(pkg),
		config.Forge.JoinPath(pkg),
	)
}

func sourceString(config *Config, pkg string) string {
	return fmt.Sprintf("%s _ %s %s",
		config.Domain.JoinPath(pkg),
		config.Forge.JoinPath(pkg).String()+"/tree/main{/dir}",
		config.Forge.JoinPath(pkg).String()+"/tree/main{/dir}/{file}#n{line}",
	)
}

func godocURL(config *Config, pkg string) string {
	return must(url.JoinPath("https://pkg.go.dev", packageImportPath(config, pkg)))
}

func badgeURL(config *Config, pkg string) string {
	return must(url.JoinPath("https://pkg.go.dev/badge/", packageImportPath(config, pkg)))
}

func packageImportPath(config *Config, pkg string) string {
	return config.Domain.JoinPath(pkg).String()
}

func packageForgeURL(config *Config, pkg string) string {
	return config.Forge.JoinPath(pkg).String()
}

func getConfig(filename string) (cfg *Config, err error) {
	cfg = new(Config)
	file, err := os.Open(filename)
	if err != nil {
		return nil, err
	}
	defer file.Close()
	dec := yaml.NewDecoder(file)
	dec.KnownFields(true)
	err = dec.Decode(cfg)
	if err != nil {
		return nil, err
	}

	return cfg, nil
}

const destDir = "dist"

func renderToFile(c gomponents.Node, filename string) error {
	pathname := filepath.Join(destDir, filename)
	err := os.MkdirAll(filepath.Dir(pathname), 0755)
	if err != nil {
		return err
	}
	file, err := os.Create(pathname)
	if err != nil {
		return err
	}
	defer file.Close()

	return c.Render(file)
}

func main() {
	cfg, err := getConfig("vanity.yaml")
	fatal(err)

	err = renderToFile(
		ListPage(cfg),
		"index.html",
	)
	fatal(err)

	for _, pkg := range cfg.Packages {
		err = renderToFile(
			PackagePage(cfg, pkg),
			filepath.Join(pkg, "index.html"),
		)
		fatal(err)
	}
}