import axios, { AxiosRequestConfig, AxiosResponse } from 'axios';

export type AuthConfig = {
    type: 'jwt' | 'basic' | 'custom_header';
    jwt_token?: string;             // Used for JWT
    username?: string;              // Used for Basic Auth
    password?: string;              // Used for Basic Auth
    custom_header?: string;         // Used for sending a custom Header
    custom_header_value?: string;   // Used for sending a custom Header
};

type UploadFunction = (
    uploadEndpoint: string,
    file: File,
    authConfig?: AuthConfig
) => Promise<AxiosResponse>;

export const uploadStrategies: Record<string, UploadFunction> = {
    'form': uploadFileForm,
    'json': uploadFileJson
};

function applyAuthConfig(config: AxiosRequestConfig, authConfig?: AuthConfig): AxiosRequestConfig {
    if (!authConfig) {
        return config;
    }

    const newConfig = { ...config };

    if (!newConfig.headers) {
        newConfig.headers = {};
    }

    switch (authConfig.type) {
        case 'jwt':
            if (authConfig.jwt_token) {
                newConfig.headers['Authorization'] = `Bearer ${authConfig.jwt_token}`;
            } else {
                console.error('JWT auth configured but no token provided');
            }
            break;

        case 'basic':
            if (authConfig.username && authConfig.password) {
                const credentials = `${authConfig.username}:${authConfig.password}`;
                const encoded = typeof btoa === 'function'
                    ? btoa(credentials)
                    : Buffer.from(credentials).toString('base64');
                newConfig.headers['Authorization'] = `Basic ${encoded}`;
            } else {
                console.error('Basic auth configured but missing credentials');
            }
            break;

        case 'custom_header':
            if (authConfig.custom_header_value) {
                newConfig.headers[authConfig.custom_header] = authConfig.custom_header_value;
            } else {
                console.error('custom_header auth configured but no custom_header_value provided');
            }
            break;
    }

    return newConfig;
}

export function uploadFileForm(
    uploadEndpoint: string,
    file: File,
    authConfig?: AuthConfig
): Promise<AxiosResponse> {
    return new Promise((resolve, reject) => {
        const formData = new FormData();
        formData.append('file', file);

        const config = applyAuthConfig({}, authConfig);

        axios
            .post(uploadEndpoint, formData, config)
            .then(response => resolve(response))
            .catch(err => {
                console.error(err);
                reject('Upload failed');
            });
    });
}

export function uploadFileJson(
    uploadEndpoint: string,
    file: File,
    authConfig?: AuthConfig
): Promise<AxiosResponse> {
    return new Promise((resolve, reject) => {
        const reader = (file: File): Promise<string | ArrayBuffer | null> => {
            return new Promise((resolve) => {
                const fileReader = new FileReader();
                fileReader.onload = () => resolve(fileReader.result);
                fileReader.readAsDataURL(file);
            });
        };

        reader(file)
            .then(result => {
                const config = applyAuthConfig({
                    headers: {
                        'Content-Type': 'application/json',
                    }
                }, authConfig);

                return axios
                    .post(uploadEndpoint, result, config)
                    .then(response => resolve(response))
                    .catch(err => {
                        console.error(err);
                        reject('Upload failed');
                    });
            });
    });
}

export function handleUploadResponse(
    response: AxiosResponse,
    jsonResponseFilePath?: string | null
): Promise<string> {
    return new Promise((resolve, reject) => {
        const contentType = response.headers['content-type'] || '';

        if (contentType.includes('application/json') && jsonResponseFilePath) {
            const pathParts = jsonResponseFilePath.split('.');
            let result = response.data;

            try {
                for (const part of pathParts) {
                    if (result && typeof result === 'object' && part in result) {
                        result = result[part];
                    } else {
                        throw new Error(`Invalid json path for response: '${jsonResponseFilePath}'. Property '${part}' not found.`);
                    }
                }

                if (typeof result !== 'string') {
                    result = String(result);
                }

                resolve(result);
            } catch (error: unknown) {
                console.error(error);
                if (error instanceof Error) {
                    reject(`Error while processing upload response: ${error.message}`);
                } else {
                    reject('Unknown error while processing upload response');
                }
            }
        } else {
            const result = typeof response.data === 'string' ?
                response.data :
                JSON.stringify(response.data);

            resolve(result);
        }
    });
}