/*

Copyright 2017 Mikael Berthe

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

*/

package madon

import (

	"bytes"

	"encoding/base64"

	"encoding/json"

	"fmt"

	"mime/multipart"

	"net/http"

	"os"

	"strconv"

	"strings"

	"github.com/pkg/errors"

	"github.com/sendgrid/rest"

)

// getAccountsOptions contains option fields for POST and DELETE API calls

type getAccountsOptions struct {

	// The ID is used for most commands

	ID int64

	// The Q field (query) is used when searching for accounts

	Q string

	Limit *LimitParams

}

// getSingleAccount returns an account entity

// The operation 'op' can be "account", "verify_credentials", "follow",

// "unfollow", "block", "unblock", "mute", "unmute",

// "follow_requests/authorize" or // "follow_requests/reject".

// The id is optional and depends on the operation.

func (mc *Client) getSingleAccount(op string, id int64) (*Account, error) {

	var endPoint string

	method := rest.Get

	strID := strconv.FormatInt(id, 10)

	switch op {

	case "account":

		endPoint = "accounts/" + strID

	case "verify_credentials":

		endPoint = "accounts/verify_credentials"

	case "follow", "unfollow", "block", "unblock", "mute", "unmute":

		endPoint = "accounts/" + strID + "/" + op

		method = rest.Post

	case "follow_requests/authorize", "follow_requests/reject":

		// The documentation is incorrect, the endpoint actually

		// is "follow_requests/:id/{authorize|reject}"

		endPoint = op[:16] + strID + "/" + op[16:]

		method = rest.Post

	default:

		return nil, ErrInvalidParameter

	}

	var account Account

	if err := mc.apiCall(endPoint, method, nil, nil, nil, &account); err != nil {

		return nil, err

	}

	return &account, nil

}

// getMultipleAccounts returns a list of account entities

// If lopt.All is true, several requests will be made until the API server

// has nothing to return.

func (mc *Client) getMultipleAccounts(endPoint string, params apiCallParams, lopt *LimitParams) ([]Account, error) {

	var accounts []Account

	var links apiLinks

	if err := mc.apiCall(endPoint, rest.Get, params, lopt, &links, &accounts); err != nil {

		return nil, err

	}

	if lopt != nil { // Fetch more pages to reach our limit

		var accountSlice []Account

		for (lopt.All || lopt.Limit > len(accounts)) && links.next != nil {

			newlopt := links.next

			links = apiLinks{}

			if err := mc.apiCall(endPoint, rest.Get, params, newlopt, &links, &accountSlice); err != nil {

				return nil, err

			}

			accounts = append(accounts, accountSlice...)

			accountSlice = accountSlice[:0] // Clear struct

		}

	}

	return accounts, nil

}

// getMultipleAccountsHelper returns a list of account entities

// The operation 'op' can be "followers", "following", "search", "blocks",

// "mutes", "follow_requests".

// The id is optional and depends on the operation.

// If opts.All is true, several requests will be made until the API server

// has nothing to return.

func (mc *Client) getMultipleAccountsHelper(op string, opts *getAccountsOptions) ([]Account, error) {

	var endPoint string

	var lopt *LimitParams

	if opts != nil {

		lopt = opts.Limit

	}

	switch op {

	case "followers", "following":

		if opts == nil || opts.ID < 1 {

			return []Account{}, ErrInvalidID

		}

		endPoint = "accounts/" + strconv.FormatInt(opts.ID, 10) + "/" + op

	case "follow_requests", "blocks", "mutes":

		endPoint = op

	case "search":

		if opts == nil || opts.Q == "" {

			return []Account{}, ErrInvalidParameter

		}

		endPoint = "accounts/" + op

	case "reblogged_by", "favourited_by":

		if opts == nil || opts.ID < 1 {

			return []Account{}, ErrInvalidID

		}

		endPoint = "statuses/" + strconv.FormatInt(opts.ID, 10) + "/" + op

	default:

		return nil, ErrInvalidParameter

	}

	// Handle target-specific query parameters

	params := make(apiCallParams)

	if op == "search" {

		params["q"] = opts.Q

	}

	return mc.getMultipleAccounts(endPoint, params, lopt)

}

// GetAccount returns an account entity

// The returned value can be nil if there is an error or if the

// requested ID does not exist.

func (mc *Client) GetAccount(accountID int64) (*Account, error) {

	account, err := mc.getSingleAccount("account", accountID)

	if err != nil {

		return nil, err

	}

	if account != nil && account.ID == 0 {

		return nil, ErrEntityNotFound

	}

	return account, nil

}

// GetCurrentAccount returns the current user account

func (mc *Client) GetCurrentAccount() (*Account, error) {

	account, err := mc.getSingleAccount("verify_credentials", 0)

	if err != nil {

		return nil, err

	}

	if account != nil && account.ID == 0 {

		return nil, ErrEntityNotFound

	}

	return account, nil

}

// GetAccountFollowers returns the list of accounts following a given account

func (mc *Client) GetAccountFollowers(accountID int64, lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{ID: accountID, Limit: lopt}

	return mc.getMultipleAccountsHelper("followers", o)

}

// GetAccountFollowing returns the list of accounts a given account is following

func (mc *Client) GetAccountFollowing(accountID int64, lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{ID: accountID, Limit: lopt}

	return mc.getMultipleAccountsHelper("following", o)

}

// FollowAccount follows an account

func (mc *Client) FollowAccount(accountID int64) error {

	account, err := mc.getSingleAccount("follow", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// UnfollowAccount unfollows an account

func (mc *Client) UnfollowAccount(accountID int64) error {

	account, err := mc.getSingleAccount("unfollow", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// FollowRemoteAccount follows a remote account

// The parameter 'uri' is a URI (e.mc. "username@domain").

func (mc *Client) FollowRemoteAccount(uri string) (*Account, error) {

	if uri == "" {

		return nil, ErrInvalidID

	}

	params := make(apiCallParams)

	params["uri"] = uri

	var account Account

	if err := mc.apiCall("follows", rest.Post, params, nil, nil, &account); err != nil {

		return nil, err

	}

	if account.ID == 0 {

		return nil, ErrEntityNotFound

	}

	return &account, nil

}

// BlockAccount blocks an account

func (mc *Client) BlockAccount(accountID int64) error {

	account, err := mc.getSingleAccount("block", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// UnblockAccount unblocks an account

func (mc *Client) UnblockAccount(accountID int64) error {

	account, err := mc.getSingleAccount("unblock", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// MuteAccount mutes an account

func (mc *Client) MuteAccount(accountID int64) error {

	account, err := mc.getSingleAccount("mute", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// UnmuteAccount unmutes an account

func (mc *Client) UnmuteAccount(accountID int64) error {

	account, err := mc.getSingleAccount("unmute", accountID)

	if err != nil {

		return err

	}

	if account != nil && account.ID != accountID {

		return ErrEntityNotFound

	}

	return nil

}

// SearchAccounts returns a list of accounts matching the query string

// The lopt parameter is optional (can be nil) or can be used to set a limit.

func (mc *Client) SearchAccounts(query string, lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{Q: query, Limit: lopt}

	return mc.getMultipleAccountsHelper("search", o)

}

// GetBlockedAccounts returns the list of blocked accounts

// The lopt parameter is optional (can be nil).

func (mc *Client) GetBlockedAccounts(lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{Limit: lopt}

	return mc.getMultipleAccountsHelper("blocks", o)

}

// GetMutedAccounts returns the list of muted accounts

// The lopt parameter is optional (can be nil).

func (mc *Client) GetMutedAccounts(lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{Limit: lopt}

	return mc.getMultipleAccountsHelper("mutes", o)

}

// GetAccountFollowRequests returns the list of follow requests accounts

// The lopt parameter is optional (can be nil).

func (mc *Client) GetAccountFollowRequests(lopt *LimitParams) ([]Account, error) {

	o := &getAccountsOptions{Limit: lopt}

	return mc.getMultipleAccountsHelper("follow_requests", o)

}

// GetAccountRelationships returns a list of relationship entities for the given accounts

func (mc *Client) GetAccountRelationships(accountIDs []int64) ([]Relationship, error) {

	if len(accountIDs) < 1 {

		return nil, ErrInvalidID

	}

	params := make(apiCallParams)

	for i, id := range accountIDs {

		if id < 1 {

			return nil, ErrInvalidID

		}

		qID := fmt.Sprintf("id[%d]", i+1)

		params[qID] = strconv.FormatInt(id, 10)

	}

	var rl []Relationship

	if err := mc.apiCall("accounts/relationships", rest.Get, params, nil, nil, &rl); err != nil {

		return nil, err

	}

	return rl, nil

}

// GetAccountStatuses returns a list of status entities for the given account

// If onlyMedia is true, returns only statuses that have media attachments.

// If excludeReplies is true, skip statuses that reply to other statuses.

// If lopt.All is true, several requests will be made until the API server

// has nothing to return.

// If lopt.Limit is set (and not All), several queries can be made until the

// limit is reached.

func (mc *Client) GetAccountStatuses(accountID int64, onlyMedia, excludeReplies bool, lopt *LimitParams) ([]Status, error) {

	if accountID < 1 {

		return nil, ErrInvalidID

	}

	endPoint := "accounts/" + strconv.FormatInt(accountID, 10) + "/" + "statuses"

	params := make(apiCallParams)

	if onlyMedia {

		params["only_media"] = "true"

	}

	if excludeReplies {

		params["exclude_replies"] = "true"

	}

	return mc.getMultipleStatuses(endPoint, params, lopt)

}

// FollowRequestAuthorize authorizes or rejects an account follow-request

func (mc *Client) FollowRequestAuthorize(accountID int64, authorize bool) error {

	endPoint := "follow_requests/reject"

	if authorize {

		endPoint = "follow_requests/authorize"

	}

	_, err := mc.getSingleAccount(endPoint, accountID)

	return err

}

// UpdateAccount updates the connected user's account data

// The fields avatar & headerImage can contain base64-encoded images; if

// they do not (that is; if they don't contain ";base64,"), they are considered

// as file paths and their content will be encoded.

// All fields can be nil, in which case they are not updated.

// displayName and note can be set to "" to delete previous values;

// I'm not sure images can be deleted -- only replaced AFAICS.

func (mc *Client) UpdateAccount(displayName, note, avatar, headerImage *string) (*Account, error) {

	const endPoint = "accounts/update_credentials"

	params := make(apiCallParams)

	if displayName != nil {

		params["display_name"] = *displayName

	}

	if note != nil {

		params["note"] = *note

	}

	var err error

	avatar, err = fileToBase64(avatar, nil)

	if err != nil {

		return nil, err

	}

	headerImage, err = fileToBase64(headerImage, nil)

	if err != nil {

		return nil, err

	}