package server

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"

	"git.grassecon.net/urdt/ussd/config"
	"git.grassecon.net/urdt/ussd/internal/models"
	"github.com/grassrootseconomics/eth-custodial/pkg/api"
)

var (
	okResponse  api.OKResponse
	errResponse api.ErrResponse
)

type AccountServiceInterface interface {
	CheckBalance(ctx context.Context, publicKey string) (*models.BalanceResponse, error)
	CreateAccount(ctx context.Context) (*api.OKResponse, error)
	CheckAccountStatus(ctx context.Context, trackingId string) (*models.TrackStatusResponse, error)
	TrackAccountStatus(ctx context.Context, publicKey string) (*api.OKResponse, error)
	FetchVouchers(ctx context.Context, publicKey string) (*models.VoucherHoldingResponse, error)
}

type AccountService struct {
}

// Parameters:
//   - trackingId: A unique identifier for the account.This should be obtained from a previous call to
//     CreateAccount or a similar function that returns an AccountResponse. The `trackingId` field in the
//     AccountResponse struct can be used here to check the account status during a transaction.
//
// Returns:
//   - string: The status of the transaction as a string. If there is an error during the request or processing, this will be an empty string.
//   - error: An error if any occurred during the HTTP request, reading the response, or unmarshalling the JSON data.
//     If no error occurs, this will be nil
func (as *AccountService) CheckAccountStatus(ctx context.Context, trackingId string) (*models.TrackStatusResponse, error) {
	resp, err := http.Get(config.BalanceURL + trackingId)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	var trackResp models.TrackStatusResponse
	err = json.Unmarshal(body, &trackResp)
	if err != nil {
		return nil, err
	}
	return &trackResp, nil

}

func (as *AccountService) TrackAccountStatus(ctx context.Context, publicKey string) (*api.OKResponse, error) {
	var err error
	// Construct the URL with the path parameter
	url := fmt.Sprintf("%s/%s", config.TrackURL, publicKey)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-GE-KEY", "xd")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		errResponse.Description = err.Error()
		return nil, err
	}
	if resp.StatusCode >= http.StatusBadRequest {
		err := json.Unmarshal([]byte(body), &errResponse)
		if err != nil {
			return nil, err
		}
		return nil, errors.New(errResponse.Description)
	}
	err = json.Unmarshal([]byte(body), &okResponse)
	if err != nil {
		return nil, err
	}
	if len(okResponse.Result) == 0 {
		return nil, errors.New("Empty api result")
	}
	return &okResponse, nil

}

// CheckBalance retrieves the balance for a given public key from the custodial balance API endpoint.
// Parameters:
//   - publicKey: The public key associated with the account whose balance needs to be checked.
func (as *AccountService) CheckBalance(ctx context.Context, publicKey string) (*models.BalanceResponse, error) {
	resp, err := http.Get(config.BalanceURL + publicKey)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	var balanceResp models.BalanceResponse
	err = json.Unmarshal(body, &balanceResp)
	if err != nil {
		return nil, err
	}
	return &balanceResp, nil
}

// CreateAccount creates a new account in the custodial system.
// Returns:
//   - *models.AccountResponse: A pointer to an AccountResponse struct containing the details of the created account.
//     If there is an error during the request or processing, this will be nil.
//   - error: An error if any occurred during the HTTP request, reading the response, or unmarshalling the JSON data.
//     If no error occurs, this will be nil.
func (as *AccountService) CreateAccount(ctx context.Context) (*api.OKResponse, error) {
	var err error

	// Create a new request
	req, err := http.NewRequest("POST", config.CreateAccountURL, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-GE-KEY", "xd")

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		errResponse.Description = err.Error()
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode >= http.StatusBadRequest {
		err := json.Unmarshal([]byte(body), &errResponse)
		if err != nil {
			return nil, err
		}
		return nil, errors.New(errResponse.Description)
	}
	err = json.Unmarshal([]byte(body), &okResponse)
	if err != nil {
		return nil, err
	}
	if len(okResponse.Result) == 0 {
		return nil, errors.New("Empty api result")
	}
	return &okResponse, nil
}

// FetchVouchers retrieves the token holdings for a given public key from the custodial holdings API endpoint
// Parameters:
//   - publicKey: The public key associated with the account.
func (as *AccountService) FetchVouchers(ctx context.Context, publicKey string) (*models.VoucherHoldingResponse, error) {
	file, err := os.Open("sample_tokens.json")
	if err != nil {
		return nil, err
	}
	defer file.Close()
	var holdings models.VoucherHoldingResponse

	if err := json.NewDecoder(file).Decode(&holdings); err != nil {
		return nil, err
	}
	return &holdings, nil
}