1 files changed, 179 insertions, 0 deletions
diff --git a/src/cmd/export/posts.go b/src/cmd/export/posts.go
new file mode 100644
index 0000000..f54fc2c
--- /dev/null
+++ b/src/cmd/export/posts.go
@@ -0,0 +1,179 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	txttpl "text/template"
+
+	gmnhg "github.com/tdemin/gmnhg"
+
+	"dev.mediocregopher.com/mediocre-blog.git/src/gmi"
+	"dev.mediocregopher.com/mediocre-blog.git/src/http"
+	"dev.mediocregopher.com/mediocre-blog.git/src/post"
+	"dev.mediocregopher.com/mediocre-blog.git/src/render"
+	"dev.mediocregopher.com/mediocre-go-lib.git/mctx"
+	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
+)
+
+var postFileExtensions = map[post.Format]string{
+	post.FormatGemtext:  "gmi",
+	post.FormatMarkdown: "md",
+}
+
+func postTargetFormat(p post.StoredPost) post.Format {
+	if p.Format == post.FormatMarkdown && strings.Contains(p.Body, `</`) {
+		return post.FormatMarkdown
+	}
+	return post.FormatGemtext
+}
+
+func writePostBody(post post.StoredPost, path, body string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("opening file: %w", err)
+	}
+	defer func() { _ = f.Close() }()
+
+	writeString := func(str string) {
+		if err != nil {
+			return
+		}
+		_, err = f.WriteString(str)
+	}
+
+	writeString(fmt.Sprintf("# %s\n\n", post.Title))
+	if post.Description != "" {
+		writeString(fmt.Sprintf("> %s\n\n", post.Description))
+	}
+	writeString(body)
+
+	return err
+}
+
+func writePosts(
+	urlBuilder render.URLBuilder, posts []post.StoredPost, path string,
+) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("opening file: %w", err)
+	}
+	defer func() { _ = f.Close() }()
+
+	writeString := func(str string) {
+		if err != nil {
+			return
+		}
+		_, err = f.WriteString(str)
+	}
+
+	writeString("# Posts\n\n")
+	for _, p := range posts {
+		var (
+			targetFormat = postTargetFormat(p)
+			u            = urlBuilder.Post(p.ID)
+		)
+
+		if targetFormat == post.FormatMarkdown {
+			u = u.HTTP()
+		}
+
+		writeString(fmt.Sprintf(
+			"=> %s %s - %s\n\n",
+			u.String(),
+			p.PublishedAt.Format("2006-01-02"),
+			p.Title,
+		))
+	}
+
+	return err
+}
+
+func exportPosts(
+	ctx context.Context,
+	logger *mlog.Logger,
+	postStore post.Store,
+	urlBuilder render.URLBuilder,
+	exportDirPath string,
+) error {
+	var (
+		postsDir        = filepath.Join(exportDirPath, "posts")
+		preprocessFuncs = map[post.Format]post.PreprocessFunctions{
+			post.FormatGemtext:  gmi.PostPreprocessFuncs{URLBuilder: urlBuilder},
+			post.FormatMarkdown: http.NewPostPreprocessFuncs(urlBuilder),
+		}
+	)
+
+	if err := os.MkdirAll(postsDir, 0755); err != nil {
+		return fmt.Errorf("creating posts dir %q: %w", postsDir, err)
+	}
+
+	logger.Info(ctx, "Getting posts")
+	posts, _, err := postStore.Get(0, 10000)
+	if err != nil {
+		return fmt.Errorf("getting posts: %w", err)
+	}
+
+	{
+		postsIndexPath := filepath.Join(postsDir, "index.gmi")
+		ctx := mctx.Annotate(ctx, "path", postsIndexPath)
+		logger.Info(ctx, "Writing posts index page")
+		err = writePosts(urlBuilder, posts, postsIndexPath)
+		if err != nil {
+			return fmt.Errorf("writing posts index page: %w", err)
+		}
+	}
+
+	for _, p := range posts {
+		var (
+			targetFormat = postTargetFormat(p)
+			ext          = postFileExtensions[targetFormat]
+			postFilePath = filepath.Join(postsDir, p.ID+"."+ext)
+
+			ctx = mctx.Annotate(
+				ctx,
+				"post_id", p.ID,
+				"post_title", p.Title,
+				"post_format", p.Format,
+				"target_format", targetFormat,
+			)
+
+			body = new(bytes.Buffer)
+		)
+
+		logger.Info(ctx, "Rendering post body")
+		tpl := txttpl.New("")
+
+		tpl, err := tpl.Parse(p.Body)
+		if err != nil {
+			return fmt.Errorf("parsing post %q body as template: %w", p.ID, err)
+		}
+
+		err = tpl.Execute(body, struct {
+			RootURL render.URLBuilder
+			post.PreprocessFunctions
+		}{
+			urlBuilder, preprocessFuncs[targetFormat],
+		})
+		if err != nil {
+			return fmt.Errorf("executing post %q body as template: %w", p.ID, err)
+		}
+
+		if p.Format == post.FormatMarkdown && targetFormat == post.FormatGemtext {
+			gemtextBodyBytes, err := gmnhg.RenderMarkdown(body.Bytes(), 0)
+			if err != nil {
+				return fmt.Errorf("converting post %q from markdown: %w", p.ID, err)
+			}
+			body = bytes.NewBuffer(gemtextBodyBytes)
+		}
+
+		if err := writePostBody(p, postFilePath, body.String()); err != nil {
+			return fmt.Errorf("writing post %q body to file %q: %w", p.ID, postFilePath, err)
+		}
+	}
+
+	return nil
+}