package services

import (
	"encoding/base64"
	"net/http"
	"strings"
	"time"

	"git.secnex.io/secnex/masterlog"
	"git.secnex.io/secnex/oauth2-api/config"
	"git.secnex.io/secnex/oauth2-api/models"
	"git.secnex.io/secnex/oauth2-api/repositories"
	"git.secnex.io/secnex/oauth2-api/utils"
	"github.com/gofiber/fiber/v2"
	"github.com/golang-jwt/jwt/v5"
	"github.com/google/uuid"
)

type TokenResponse struct {
	TokenType    string `json:"token_type"`
	Scope        string `json:"scope"`
	ExpiresIn    int    `json:"expires_in"`
	ExtExpiresIn int    `json:"ext_expires_in"`
	AccessToken  string `json:"access_token"`
	RefreshToken string `json:"refresh_token"`
}

func Token(clientID, grantType, code, redirectURI, clientSecret string) *utils.HTTPResponse {
	now := time.Now().UTC()
	application, err := repositories.GetApplicationByID(clientID)
	if err != nil {
		masterlog.Debug("Application not found", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Application not found"}, "", nil, nil)
	}
	if application.ExpiresAt.Before(time.Now().UTC()) {
		masterlog.Debug("Application expired", map[string]interface{}{"client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Application expired"}, "", nil, nil)
	}
	valid, err := utils.Verify(clientSecret, application.Secret)
	if err != nil {
		masterlog.Debug("Invalid client secret", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid client secret"}, "", nil, nil)
	}
	if !valid {
		masterlog.Debug("Invalid client secret", map[string]interface{}{"client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid client secret"}, "", nil, nil)
	}

	authorizationCodePlain, err := base64.StdEncoding.DecodeString(code)
	if err != nil {
		masterlog.Debug("Invalid authorization code", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid authorization code"}, "", nil, nil)
	}
	authorizationCodeParts := strings.Split(string(authorizationCodePlain), ":")
	if len(authorizationCodeParts) != 2 {
		masterlog.Debug("Invalid authorization code", map[string]interface{}{"client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid authorization code"}, "", nil, nil)
	}
	authorizationID := uuid.MustParse(authorizationCodeParts[0])
	authorizationCode := authorizationCodeParts[1]
	authorization, err := repositories.GetAuthorizationByID(authorizationID.String())
	if err != nil {
		masterlog.Debug("Authorization not found", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Authorization not found"}, "", nil, nil)
	}
	codeValid, err := utils.Verify(authorizationCode, authorization.Code)
	if err != nil {
		masterlog.Debug("Invalid authorization code", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid authorization code"}, "", nil, nil)
	}
	if !codeValid {
		masterlog.Debug("Invalid authorization code", map[string]interface{}{"client_id": clientID})
		return utils.NewHTTPResponse(http.StatusUnauthorized, &fiber.Map{"error": "Invalid authorization code"}, "", nil, nil)
	}

	tokenID := uuid.New()
	refreshToken := utils.GenerateRandomString(64)
	token := &models.Token{
		ID:           tokenID,
		RefreshToken: refreshToken,
		UserID:       authorization.UserID,
	}
	if err := repositories.CreateToken(token); err != nil {
		masterlog.Debug("Failed to create token", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusInternalServerError, &fiber.Map{"error": "Failed to create token"}, "", nil, nil)
	}

	if err := repositories.ExpireAuthorization(authorizationID.String()); err != nil {
		masterlog.Debug("Failed to expire authorization", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusInternalServerError, &fiber.Map{"error": "Failed to expire authorization"}, "", nil, nil)
	}

	user, err := repositories.GetUserByID(authorization.UserID.String())
	if err != nil {
		masterlog.Debug("Failed to get user", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusInternalServerError, &fiber.Map{"error": "Failed to get user"}, "", nil, nil)
	}

	userClaims := map[string]interface{}{
		"id":         user.ID.String(),
		"username":   user.Username,
		"email":      user.Email,
		"first_name": user.FirstName,
		"last_name":  user.LastName,
	}
	if user.TenantID != nil {
		userClaims["tenant_id"] = user.TenantID.String()
	}
	if user.ExternalID != nil {
		userClaims["external_id"] = user.ExternalID.String()
	}

	accessToken := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"sub":  tokenID.String(),
		"exp":  token.SessionExpiresAt.Unix(),
		"iat":  now.Unix(),
		"aud":  clientID,
		"iss":  "https://secnex.io",
		"user": userClaims,
	})

	secret := config.CONFIG.JwtSecret
	accessTokenString, err := accessToken.SignedString([]byte(secret))
	if err != nil {
		masterlog.Debug("Failed to sign access token", map[string]interface{}{"error": err.Error(), "client_id": clientID})
		return utils.NewHTTPResponse(http.StatusInternalServerError, &fiber.Map{"error": "Failed to sign access token"}, "", nil, nil)
	}

	tokenExpiresAt := token.SessionExpiresAt.Unix()
	extTokenExpiresAt := token.RefreshTokenExpiresAt.Unix()
	response := TokenResponse{
		TokenType:    "Bearer",
		Scope:        "",
		ExpiresIn:    int(tokenExpiresAt - now.Unix()),
		ExtExpiresIn: int(extTokenExpiresAt - now.Unix()),
		AccessToken:  accessTokenString,
		RefreshToken: refreshToken,
	}
	masterlog.Debug("Token created successfully", map[string]interface{}{"client_id": clientID})
	return utils.NewHTTPResponse(http.StatusOK, &fiber.Map{"response": response}, "", nil, nil)
}