package main

import (
	"flag"
	"fmt"
	"io/fs"
	"os"
	// "path/filepath"
	"strings"

	"go.uber.org/zap"
)

func NewAttachmentMover() *AttachmentMover {
	var am AttachmentMover
	l, _ := zap.NewProduction()
	am.L = l
	am.Attachments = make(map[string]bool)
	am.Posts = make([]string, 0)

	return &am
}

type AttachmentMover struct {
	Source, Target          string
	Attachments             map[string]bool
	Posts                   []string
	L                       *zap.Logger
	BlogDir, AttachmentsDir string
}

func (am *AttachmentMover) Walk() error {
	notesRoot := os.DirFS(am.Source)
	blogRoot := os.DirFS(am.Target)

	err := fs.WalkDir(notesRoot, ".", am.findAttachments)
	if err != nil {
		return fmt.Errorf("error scanning for attachments: %q", err)
	}

	err = fs.WalkDir(notesRoot, ".", am.findNotes)
	if err != nil {
		return fmt.Errorf("error scanning vault for posts: %q", err)
	}

	err = fs.WalkDir(blogRoot, ".", am.findPosts)
	if err != nil {
		return fmt.Errorf("error scanning blog for posts: %q", err)
	}
	return nil
}

func (am *AttachmentMover) findNotes(path string, d fs.DirEntry, err error) error {
	if err != nil {
		return err
	}

	if d.IsDir() {
		return nil
	}
	walkLogger := am.L.Named("FindNotes")

	if strings.HasSuffix(path, ".md") && strings.Contains(path, am.BlogDir) {
		walkLogger.Info("found blog post to publish, adding to index", zap.String("path", path))
		am.Attachments[path] = true
	}
	return nil
}

func (am *AttachmentMover) findAttachments(path string, d fs.DirEntry, err error) error {
	if err != nil {
		return err
	}

	if d.IsDir() {
		return nil
	}
	walkLogger := am.L.Named("FindAttachments")

	if strings.Contains(path, am.AttachmentsDir) {
		walkLogger.Info("found attachment file, adding to index", zap.String("path", path))
		am.Attachments[path] = true
	}
	return nil
}

func (am *AttachmentMover) findPosts(path string, d fs.DirEntry, err error) error {
	if err != nil {
		return err
	}

	if d.IsDir() {
		return nil
	}
	walkLogger := am.L.Named("FindPosts")

	if strings.HasSuffix(path, "index.md") {
		walkLogger.Info("found index.md, adding to index", zap.String("path", path))
		am.Posts = append(am.Posts, path)
	}
	return nil
}

func (am *AttachmentMover) Move() error {
	moveLogger := am.L.Named("Move")
	moveLogger.Info("scanning posts", zap.Strings("posts", am.Posts))
	for _, post := range am.Posts {
		// log.Printf("scanning %q for attachment links", post)
		linkedAttachments, err := extractAttachments(post, am.L.Named("extractAttachments"))
		if err != nil {
			return fmt.Errorf("could not extract attachment links from %q: %w", post, err)
		}
		for _, attachment := range linkedAttachments {
			moveAttachment(post, attachment, am.L.Named("moveAttachment"))
		}
	}

	return nil
}

func moveAttachment(post, attachment string, l *zap.Logger) error {
	l.Info("moving attachment",
		zap.String("post", post),
		zap.String("attachment", attachment),
	)

	return nil
}

func extractAttachments(post string, l *zap.Logger) ([]string, error) {
	l.Info("extracting attachment",
		zap.String("post", post),
	)
	attachments := make([]string, 0)

	return attachments, nil
}

func main() {
	am := NewAttachmentMover()
	defer am.L.Sync()

	flag.StringVar(&am.Source, "source", "", "source directory containing your vault")
	flag.StringVar(&am.Target, "target", "", "target directory containing your hugo site")
	flag.StringVar(&am.AttachmentsDir, "attachments", "", "directory containing your vault's attachments")
	flag.StringVar(&am.BlogDir, "blog", "", "vault directory containing blog posts to-be-published")

	flag.Parse()

	switch {
	case am.Source == "":
		am.L.Fatal("please provide -source")
		fallthrough
	case am.Target == "":
		am.L.Fatal("please provide -target")
		fallthrough
	case am.AttachmentsDir == "":
		am.L.Fatal("please provide -attachments")
		fallthrough
	case am.BlogDir == "":
		am.L.Fatal("please provide -blog")
	}

	if am.Source == "" || am.Target == "" {
		am.L.Fatal("flags not provided")
	}

	err := am.Walk()
	if err != nil {
		am.L.Fatal("error walking blog or notes dir to gather file names", zap.Error(err))
	}

	err = am.Move()
	if err != nil {
		am.L.Fatal("error moving notes", zap.Error(err))
	}
}