nim/internal/handlers/post.go

package handlers

import (
	"crypto/sha256"
	"encoding/base64"
	"log"
	"mime"
	"path"
	"strconv"
	"strings"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	"nim.jasinco.work/app/internal"
	"nim.jasinco.work/app/nimdb"
)

var supported_filetype = []string{"image/png", "image/jpeg", "image/webp", "image/gif", "image/heif", "video/H264", "video/H265", "video/mp4"}

func find_supported(mimetype string) bool {
	for _, supported := range supported_filetype {
		if strings.Compare(supported, mimetype) == 0 {
			return true
		}
	}
	return false
}

func Fetch_post(c *fiber.Ctx) error {
	cursor := c.Query("cursor")

	ctx := c.Context()

	var rec []nimdb.GetPostRow
	var err error
	if len(cursor) == 0 {
		rec, err = internal.NIMDB.GetPost(ctx, internal.FETCH_LENGTH)
		if err != nil {
			log.Println(err)
			return fiber.ErrInternalServerError
		}
	} else if cursor_num, err := strconv.Atoi(cursor); err == nil {
		rec_cur, err := internal.NIMDB.GetPostWithCursor(ctx, nimdb.GetPostWithCursorParams{ID: int32(cursor_num), Limit: internal.FETCH_LENGTH})
		if err != nil {
			log.Println(err)
			return c.Status(500).SendString("Failed to Query DB")
		}
		rec = make([]nimdb.GetPostRow, len(rec_cur))
		for id, val := range rec_cur {
			rec[id] = nimdb.GetPostRow(val)
		}
	} else {
		return c.Status(fiber.StatusBadRequest).SendString("Can't parse cursor")
	}
	if len(rec) == 0 {
		return c.SendStatus(fiber.StatusNoContent)
	}

	return c.JSON(rec)
}

func Delete_post(c *fiber.Ctx) error {
	post := c.Query("post")
	hash := c.Query("hash")
	ctx := c.Context()
	post_id, err := strconv.Atoi(post)
	if err != nil {
		return c.Status(500).SendString("Failed to Parse Int")
	}

	tx, err := internal.POOL.Begin(ctx)
	if err != nil {
		return c.Status(500).SendString("Failed to Start Transaction")
	}
	defer tx.Rollback(ctx)
	qtx := internal.NIMDB.WithTx(tx)
	if err = qtx.DeletePost(ctx, nimdb.DeletePostParams{ID: int32(post_id), Hash: hash}); err != nil {
		return err
	}
	if err = qtx.InvalidateMedia(ctx, pgtype.Int4{Int32: int32(post_id)}); err != nil {
		return err
	}

	if tx.Commit(ctx) != nil {
		return c.Status(500).SendString("Failed to Commit")
	}

	return c.SendStatus(200)
}

func Insert_Post(c *fiber.Ctx) error {
	ctx := c.Context()

	tx, err := internal.POOL.Begin(ctx)
	if err != nil {
		return c.Status(500).SendString("Failed to Start Transaction")
	}
	defer tx.Rollback(ctx)
	qtx := internal.NIMDB.WithTx(tx)

	if form, err := c.MultipartForm(); err == nil {

		content := form.Value["content"]
		signing := form.Value["signing"]
		files := form.File["enclosure"]
		if len(content) == 0 || len(content[0]) == 0 {
			return fiber.ErrBadRequest
		}
		post_hash := sha256.New()
		post_hash.Write([]byte(content[0]))
		signing_pgt := new(pgtype.Text)
		signing_pgt.Valid = false
		if len(signing) > 0 && len(signing[0]) > 0 {
			post_hash.Write([]byte(signing[0]))
			signing_pgt.Valid = true
			signing_pgt.String = signing[0]
		}
		now, err := time.Now().MarshalBinary()
		if err != nil {
			c.SendString("Failed to get time")
			return c.SendStatus(500)
		}

		credential, err := qtx.InsertPost(ctx,
			nimdb.InsertPostParams{
				Content: content[0],
				Signing: *signing_pgt,
				Hash:    base64.StdEncoding.EncodeToString(post_hash.Sum(now)),
			},
		)
		if err != nil {
			log.Println(err.Error())
			return c.Status(500).SendString("Failed to insert post")
		}

		for _, file := range files {
			filemime, _, err := mime.ParseMediaType(file.Header.Get("Content-Type"))
			if err != nil {
				return c.Status(fiber.ErrBadRequest.Code).SendString("Failed to parse content type")
			}
			if !find_supported(filemime) {
				return c.Status(fiber.ErrBadRequest.Code).SendString("Unsupported Type")
			}

			filetype := strings.Split(filemime, "/")[0]
			mid, err := uuid.NewRandom()
			if err != nil {
				c.SendString("Faild to generate UUIDv4")
				return c.SendStatus(500)
			}

			fxnamepath := filetype + "/" + mid.String()
			if err = c.SaveFile(file, path.Join("./static", fxnamepath)); err != nil {
				log.Println("Can't save to ./static", err.Error())
				return fiber.ErrInternalServerError
			}

			if err := qtx.InsertPostImage(ctx, nimdb.InsertPostImageParams{
				Url:    fxnamepath,
				PostID: pgtype.Int4{Int32: credential.ID, Valid: true},
			}); err != nil {
				log.Println(err.Error())
				return c.Status(500).SendString("Failed to insert image")
			}
		}
		if err = tx.Commit(ctx); err != nil {
			log.Println(err.Error())
			c.SendString("Failed to send Commit")
			return c.SendStatus(500)
		}
		return c.JSON(credential)
	}

	return fiber.ErrBadRequest
}