package client

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"
)

// LoginParams represents the parameters for login.
type LoginParams struct {
	User     string `json:"user"`
	Password string `json:"password,omitempty"`
	Token    string `json:"token,omitempty"`
	TOTPCode string `json:"totp_code,omitempty"`
}

// LoginRequest represents a login request to the MCIAS API.
type LoginRequest struct {
	Version string      `json:"version"`
	Login   LoginParams `json:"login"`
}

// TOTPVerifyRequest represents a TOTP verification request.
type TOTPVerifyRequest struct {
	Version  string `json:"version"`
	Username string `json:"username"`
	TOTPCode string `json:"totp_code"`
}

// TokenResponse represents the response from a login or TOTP verification request.
type TokenResponse struct {
	Token       string `json:"token"`
	Expires     int64  `json:"expires"`
	TOTPEnabled bool   `json:"totp_enabled,omitempty"`
}

// ErrorResponse represents an error response from the API.
type ErrorResponse struct {
	Error     string `json:"error"`
	ErrorCode string `json:"error_code,omitempty"`
}

// LoginWithPassword authenticates with the MCIAS server using a username and password.
// If TOTP is enabled for the user, the TOTPEnabled field in the response will be true,
// and the client will need to call VerifyTOTP to complete authentication.
func (c *Client) LoginWithPassword(ctx context.Context, username, password string) (*TokenResponse, error) {
	loginReq := LoginRequest{
		Version: "v1",
		Login: LoginParams{
			User:     username,
			Password: password,
		},
	}

	jsonData, err := json.Marshal(loginReq)
	if err != nil {
		return nil, fmt.Errorf("error creating request: %w", err)
	}

	url := fmt.Sprintf("%s/v1/login/password", c.BaseURL)
	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		var errResp ErrorResponse
		if unmarshalErr := json.Unmarshal(body, &errResp); unmarshalErr == nil {
			return nil, fmt.Errorf("API error: %s (code: %s)", errResp.Error, errResp.ErrorCode)
		}
		return nil, fmt.Errorf("API error: %s", resp.Status)
	}

	var tokenResp TokenResponse
	if err := json.Unmarshal(body, &tokenResp); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	// Update client with authentication info
	c.Token = tokenResp.Token
	c.Username = username

	return &tokenResp, nil
}

// LoginWithToken authenticates with the MCIAS server using a token.
func (c *Client) LoginWithToken(ctx context.Context, username, token string) (*TokenResponse, error) {
	loginReq := LoginRequest{
		Version: "v1",
		Login: LoginParams{
			User:  username,
			Token: token,
		},
	}

	jsonData, err := json.Marshal(loginReq)
	if err != nil {
		return nil, fmt.Errorf("error creating request: %w", err)
	}

	url := fmt.Sprintf("%s/v1/login/token", c.BaseURL)
	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		var errResp ErrorResponse
		if unmarshalErr := json.Unmarshal(body, &errResp); unmarshalErr == nil {
			return nil, fmt.Errorf("API error: %s (code: %s)", errResp.Error, errResp.ErrorCode)
		}
		return nil, fmt.Errorf("API error: %s", resp.Status)
	}

	var tokenResp TokenResponse
	if err := json.Unmarshal(body, &tokenResp); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	// Update client with authentication info
	c.Token = tokenResp.Token
	c.Username = username

	return &tokenResp, nil
}

// VerifyTOTP verifies a TOTP code for a user.
func (c *Client) VerifyTOTP(ctx context.Context, username, totpCode string) (*TokenResponse, error) {
	totpReq := TOTPVerifyRequest{
		Version:  "v1",
		Username: username,
		TOTPCode: totpCode,
	}

	jsonData, err := json.Marshal(totpReq)
	if err != nil {
		return nil, fmt.Errorf("error creating request: %w", err)
	}

	url := fmt.Sprintf("%s/v1/login/totp", c.BaseURL)
	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		var errResp ErrorResponse
		if unmarshalErr := json.Unmarshal(body, &errResp); unmarshalErr == nil {
			return nil, fmt.Errorf("API error: %s (code: %s)", errResp.Error, errResp.ErrorCode)
		}
		return nil, fmt.Errorf("API error: %s", resp.Status)
	}

	var tokenResp TokenResponse
	if err := json.Unmarshal(body, &tokenResp); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	// Update client with authentication info
	c.Token = tokenResp.Token
	c.Username = username

	return &tokenResp, nil
}

// IsTokenExpired checks if the token is expired.
func (c *Client) IsTokenExpired(expiryTime int64) bool {
	return expiryTime > 0 && expiryTime < time.Now().Unix()
}