package main

import (
  "fmt"
  "html/template"
  "io/ioutil"
  "os"
  "path/filepath"
  "strings"
  "time"

  "github.com/russross/blackfriday/v2"
)

// NavItem represents a link in the navigation menu
type NavItem struct {
  Title string
  URL   string
}

func main() {
  contentDir := "./content"
  outputDir := "./public"
  templateFile := "./templates/layout.html"

  tpl, err := parseTemplate(templateFile)
  if err != nil {
    fmt.Printf("Template parsing error: %v\n", err)
    return
  }

  files, err := readContentFiles(contentDir)
  if err != nil {
    fmt.Printf("Failed to read content directory: %v\n", err)
    return
  }

  nav := buildNavigation(files)

  for _, file := range files {
    if filepath.Ext(file.Name()) == ".md" {
      err := generateHTML(file, contentDir, outputDir, tpl, nav)
      if err != nil {
        fmt.Printf("Error generating HTML for %s: %v\n", file.Name(), err)
      }
    }
  }

  fmt.Println("✅ Site generation complete.")
}

func parseTemplate(templateFile string) (*template.Template, error) {
  return template.ParseFiles(templateFile)
}

func readContentFiles(contentDir string) ([]os.FileInfo, error) {
  return ioutil.ReadDir(contentDir)
}

func buildNavigation(files []os.FileInfo) []NavItem {
  var nav []NavItem
  for _, file := range files {
    if filepath.Ext(file.Name()) == ".md" {
      name := strings.TrimSuffix(file.Name(), filepath.Ext(file.Name()))
      title := strings.Title(name)
      url := "/"
      if name != "index" {
        url = "/" + name + "/"
      }
      nav = append(nav, NavItem{Title: title, URL: url})
    }
  }
  return nav
}

func generateHTML(file os.FileInfo, contentDir, outputDir string, tpl *template.Template, nav []NavItem) error {
  name := strings.TrimSuffix(file.Name(), filepath.Ext(file.Name()))
  title := strings.Title(name)

  mdPath := filepath.Join(contentDir, file.Name())
  mdContent, err := ioutil.ReadFile(mdPath)
  if err != nil {
    return fmt.Errorf("failed to read %s: %w", file.Name(), err)
  }

  htmlContent := blackfriday.Run(mdContent)

  var outPath string
  if name == "index" {
    outPath = filepath.Join(outputDir, "index.html")
  } else {
    subDir := filepath.Join(outputDir, name)
    os.MkdirAll(subDir, os.ModePerm)
    outPath = filepath.Join(subDir, "index.html")
  }

  outFile, err := os.Create(outPath)
  if err != nil {
    return fmt.Errorf("failed to create %s: %w", outPath, err)
  }
  defer outFile.Close()

  data := map[string]interface{}{
    "Content": template.HTML(htmlContent),
    "Title":   title,
    "Nav":     nav,
    "Year":    time.Now().Year(),
    "Date":    time.Now().Format("January 2, 2006"),
  }

  return tpl.Execute(outFile, data)
}