/*

Copyright 2017-2018 Mikael Berthe

Licensed under the MIT license.  Please see the LICENSE file is this directory.

*/

package madon

import (

	"bytes"

	"encoding/json"

	"io"

	"mime/multipart"

	"os"

	"path/filepath"

	"strconv"

	"github.com/pkg/errors"

	"github.com/sendgrid/rest"

)

const mediaUploadFieldName = "file"

// UploadMedia uploads the given file and returns an attachment

// The description and focus arguments can be empty strings.

// 'focus' is the "focal point", written as two comma-delimited floating points.

func (mc *Client) UploadMedia(filePath, description, focus string) (*Attachment, error) {

	if filePath == "" {

		return nil, ErrInvalidParameter

	}

	f, err := os.Open(filePath)

	if err != nil {

		return nil, errors.Wrap(err, "cannot read file")

	}

	defer f.Close()

	return mc.UploadMediaReader(f, filepath.Base(f.Name()), description, focus)

}

// UploadMediaReader uploads data from the given reader and returns an attachment

// name, description and focus arguments can be empty strings.

// 'focus' is the "focal point", written as two comma-delimited floating points.

func (mc *Client) UploadMediaReader(f io.Reader, name, description, focus string) (*Attachment, error) {

	buf := bytes.Buffer{}

	w := multipart.NewWriter(&buf)

	var formWriter io.Writer

	var err error

	if len(name) > 0 {

		formWriter, err = w.CreateFormFile(mediaUploadFieldName, name)

	} else {

		formWriter, err = w.CreateFormField(mediaUploadFieldName)

	}

	if err != nil {

		return nil, errors.Wrap(err, "media upload")

	}

	if _, err = io.Copy(formWriter, f); err != nil {

		return nil, errors.Wrap(err, "media upload")

	}

	w.Close()

	var params apiCallParams

	if description != "" || focus != "" {

		params = make(apiCallParams)

		if description != "" {

			params["description"] = description

		}

		if focus != "" {

			params["focus"] = focus

		}

	}

	req, err := mc.prepareRequest("v1/media", rest.Post, params)

	if err != nil {

		return nil, errors.Wrap(err, "media prepareRequest failed")

	}

	req.Headers["Content-Type"] = w.FormDataContentType()

	req.Body = buf.Bytes()

	// Make API call

	r, err := restAPI(req)

	if err != nil {

		return nil, errors.Wrap(err, "media upload failed")

	}

	// Check for error reply

	var errorResult Error

	if err := json.Unmarshal([]byte(r.Body), &errorResult); err == nil {

		// The empty object is not an error

		if errorResult.Text != "" {

			return nil, errors.New(errorResult.Text)

		}

	}

	// Not an error reply; let's unmarshal the data

	var attachment Attachment

	err = json.Unmarshal([]byte(r.Body), &attachment)

	if err != nil {

		return nil, errors.Wrap(err, "cannot decode API response (media)")

	}

	return &attachment, nil

}

// UpdateMedia updates the description and focal point of a media

// One of the description and focus arguments can be nil to not be updated.

func (mc *Client) UpdateMedia(mediaID int64, description, focus *string) (*Attachment, error) {

	params := make(apiCallParams)

	if description != nil {

		params["description"] = *description

	}

	if focus != nil {

		params["focus"] = *focus

	}

	endPoint := "media/" + strconv.FormatInt(mediaID, 10)

	var attachment Attachment

	if err := mc.apiCall("v1/"+endPoint, rest.Put, params, nil, nil, &attachment); err != nil {

		return nil, err

	}

	return &attachment, nil

}