package gondole

import (

	"encoding/json"

	"fmt"

	"strconv"

	"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 int

	// The following fields are used when searching for accounts

	Q     string

	Limit int

}

// getSingleAccount returns an account entity

// The target can be "account", "verify_credentials", "follow", "unfollow",

// "block", "unblock", "mute" or "unmute".

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

func (g *Client) getSingleAccount(target string, id int) (*Account, error) {

	var endPoint string

	method := rest.Get

	strID := strconv.Itoa(id)

	switch target {

	case "account":

		endPoint = "accounts/" + strID

	case "verify_credentials":

		endPoint = "accounts/verify_credentials"

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

		endPoint = "accounts/" + strID + "/" + target

		method = rest.Post

	default:

		return nil, ErrInvalidParameter

	}

	req := g.prepareRequest(endPoint)

	req.Method = method

	r, err := rest.API(req)

	if err != nil {

		return nil, fmt.Errorf("getAccount (%s): %s", target, err.Error())

	}

	// 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, fmt.Errorf("%s", errorResult.Text)

		}

	}

	var account Account

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

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

	if err != nil {

		return nil, fmt.Errorf("getAccount (%s) API: %s", target, err.Error())

	}

	return &account, nil

}

// getMultipleAccounts returns a list of account entities

// The target can be "followers", "following", "search", "blocks", "mutes",

// "follow_requests".

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

func (g *Client) getMultipleAccounts(target string, opts *getAccountsOptions) ([]Account, error) {

	var endPoint string

	switch target {

	case "followers", "following":

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

			return []Account{}, ErrInvalidID

		}

		endPoint = "accounts/" + strconv.Itoa(opts.ID) + "/" + target

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

		endPoint = target

	case "search":

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

			return []Account{}, ErrInvalidParameter

		}

		endPoint = "accounts/" + target

	default:

		return nil, ErrInvalidParameter

	}

	req := g.prepareRequest(endPoint)

	if target == "search" {

		req.QueryParams["q"] = opts.Q

		if opts.Limit > 0 {

			req.QueryParams["limit"] = strconv.Itoa(opts.Limit)

		}

	}

	r, err := rest.API(req)

	if err != nil {

		return nil, fmt.Errorf("getAccount (%s): %s", target, err.Error())

	}

	// 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, fmt.Errorf("%s", errorResult.Text)

		}

	}

	var accounts []Account

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

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

	if err != nil {

		return nil, fmt.Errorf("getAccount (%s) API: %s", target, err.Error())

	}

	return accounts, nil

}

// 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 (g *Client) GetAccount(id int) (*Account, error) {

	account, err := g.getSingleAccount("account", id)

	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 (g *Client) GetCurrentAccount() (*Account, error) {

	account, err := g.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 (g *Client) GetAccountFollowers(accountID int) ([]Account, error) {

	o := &getAccountsOptions{ID: accountID}

	return g.getMultipleAccounts("followers", o)

}

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

func (g *Client) GetAccountFollowing(accountID int) ([]Account, error) {

	o := &getAccountsOptions{ID: accountID}

	return g.getMultipleAccounts("following", o)

}

// FollowAccount follows an account

func (g *Client) FollowAccount(id int) error {

	account, err := g.getSingleAccount("follow", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

// UnfollowAccount unfollows an account

func (g *Client) UnfollowAccount(id int) error {

	account, err := g.getSingleAccount("unfollow", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

// BlockAccount blocks an account

func (g *Client) BlockAccount(id int) error {

	account, err := g.getSingleAccount("block", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

// UnblockAccount unblocks an account

func (g *Client) UnblockAccount(id int) error {

	account, err := g.getSingleAccount("unblock", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

// MuteAccount mutes an account

func (g *Client) MuteAccount(id int) error {

	account, err := g.getSingleAccount("mute", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

// UnmuteAccount unmutes an account

func (g *Client) UnmuteAccount(id int) error {

	account, err := g.getSingleAccount("unmute", id)

	if err != nil {

		return err

	}

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

		return ErrEntityNotFound

	}

	return nil

}

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

// The limit parameter is optional (can be 0).

func (g *Client) SearchAccounts(query string, limit int) ([]Account, error) {

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

	return g.getMultipleAccounts("search", o)

}

// GetBlockedAccounts returns the list of blocked accounts

func (g *Client) GetBlockedAccounts() ([]Account, error) {

	return g.getMultipleAccounts("blocks", nil)

}

// GetMutedAccounts returns the list of muted accounts

func (g *Client) GetMutedAccounts() ([]Account, error) {

	return g.getMultipleAccounts("mutes", nil)

}

// GetAccountFollowRequests returns the list of follow requests accounts

func (g *Client) GetAccountFollowRequests() ([]Account, error) {

	return g.getMultipleAccounts("follow_requests", nil)

}