package photosapi

import (
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
)

var (
	ErrUploadNotExists = errors.New("upload id doesn't exists")
)

func (s *Service) UploadCreate(c *gin.Context) {
	sha, err := uuid.NewRandom()
	if err != nil {
		c.AbortWithError(http.StatusInternalServerError, err)
		return
	}

	if err := s.Storage.Create(StorageTmp, sha.String()); err != nil {
		c.AbortWithError(http.StatusInternalServerError, err)
		return
	}

	c.JSON(http.StatusCreated, gin.H{
		"status":    "success",
		"upload_id": sha.String(),
	})
}

type UploadUri struct {
	Id string `uri:"upload_id" binding:"required,uuid"`
}

type UploadPartQuery struct {
	Part       uint   `form:"part" binding:"required"`
	PartSha256 string `form:"sha256" binding:"required,sha256"`
}

func (s *Service) UploadPart(c *gin.Context) {
	var (
		upload     UploadUri
		uploadPart UploadPartQuery
	)

	if c.BindUri(&upload) != nil || c.BindQuery(&uploadPart) != nil {
		return
	}

	if !s.Storage.Exists(StorageTmp, upload.Id) {
		c.AbortWithError(http.StatusNotFound, ErrUploadNotExists)
		return
	}

	f, err := os.Create(
		s.Storage.Join(StorageTmp, upload.Id, fmt.Sprint(uploadPart.Part)),
	)
	if err != nil {
		c.AbortWithError(http.StatusInternalServerError, err)
		return
	}

	defer f.Close()
	defer c.Request.Body.Close()

	sha := sha256.New()
	t := io.TeeReader(c.Request.Body, sha)
	w, err := io.Copy(f, t)
	if err != nil {
		c.AbortWithError(http.StatusInternalServerError, err)
		return
	}

	c.JSON(http.StatusCreated, gin.H{
		"upload_id": upload.Id,
		"part":      uploadPart.Part,
		"size":      w,
		"sha256":    hex.EncodeToString(sha.Sum(nil)),
		"status":    "success",
	})
}

func (s *Service) UploadCancel(c *gin.Context) {
	var upload UploadUri
	if c.BindUri(&upload) != nil {
		return
	}

	if err := s.Storage.Delete(StorageTmp, upload.Id); err != nil {
		c.AbortWithError(http.StatusNotFound, ErrUploadNotExists)
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"status": "success",
	})
}

type UploadCompleteRequest struct {
	Sha256 string `json:"sha256" binding:"required,sha256"`
	Name   string `json:"name" binding:"required"`
	Parts  uint   `json:"parts" binding:"required"`
}

func (s *Service) UploadComplete(c *gin.Context) {
	var uploadCompleteRequest UploadCompleteRequest
	if c.BindJSON(&uploadCompleteRequest) != nil {
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"sha256": uploadCompleteRequest.Sha256,
		"parts":  uploadCompleteRequest.Parts,
		"name":   uploadCompleteRequest.Name,
	})
}

func (s *Service) UploadInit() {
	upload := s.Gin.Group("/upload")
	upload.GET("/create", s.UploadCreate)
	upload.POST("/part/:upload_id", s.UploadPart)
	upload.GET("/cancel/:upload_id", s.UploadCancel)
	upload.POST("/complete/:upload_id", s.UploadComplete)
}