/*

Copyright 2017-2018 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

	// Following can be set to true to limit a search to "following" accounts

	Following bool

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

	Q string

	Limit *LimitParams

}

// updateRelationship returns a Relationship entity

// The operation 'op' can be "follow", "unfollow", "block", "unblock",

// "mute", "unmute".

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

func (mc *Client) updateRelationship(op string, id int64, params apiCallParams) (*Relationship, error) {

	var endPoint string

	method := rest.Post

	strID := strconv.FormatInt(id, 10)

	switch op {

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

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

	default:

		return nil, ErrInvalidParameter

	}

	var rel Relationship

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

		return nil, err

	}

	return &rel, nil

}

// getSingleAccount returns an account entity

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

// "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_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

		if opts.Following {

			params["following"] = "true"

		}

	}

	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

// 'reblogs' can be used to specify if boots should be displayed or hidden.

func (mc *Client) FollowAccount(accountID int64, reblogs *bool) (*Relationship, error) {

	var params apiCallParams

	if reblogs != nil {

		params = make(apiCallParams)

		if *reblogs {

			params["reblogs"] = "true"

		} else {

			params["reblogs"] = "false"

		}

	}

	rel, err := mc.updateRelationship("follow", accountID, params)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, nil

}

// UnfollowAccount unfollows an account

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

	rel, err := mc.updateRelationship("unfollow", accountID, nil)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, nil

}

// FollowRemoteAccount follows a remote account

// The parameter 'uri' is a URI (e.g. "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) (*Relationship, error) {

	rel, err := mc.updateRelationship("block", accountID, nil)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, nil

}

// UnblockAccount unblocks an account

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

	rel, err := mc.updateRelationship("unblock", accountID, nil)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, nil

}

// MuteAccount mutes an account

// Note that with current Mastodon API, muteNotifications defaults to true

// when it is not provided.

func (mc *Client) MuteAccount(accountID int64, muteNotifications *bool) (*Relationship, error) {

	var params apiCallParams

	if muteNotifications != nil {

		params = make(apiCallParams)

		if *muteNotifications {

			params["notifications"] = "true"

		} else {

			params["notifications"] = "false"

		}

	}

	rel, err := mc.updateRelationship("mute", accountID, params)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, nil

}

// UnmuteAccount unmutes an account

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

	rel, err := mc.updateRelationship("unmute", accountID, nil)

	if err != nil {

		return nil, err

	}

	if rel == nil {

		return nil, ErrEntityNotFound

	}

	return rel, 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, following bool, lopt *LimitParams) ([]Account, error) {

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

	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 onlyPinned is true, returns only statuses that have been pinned.

// 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, onlyPinned, onlyMedia, excludeReplies bool, lopt *LimitParams) ([]Status, error) {

	if accountID < 1 {

		return nil, ErrInvalidID