// validation function which checks the proposed file's type, size, and name
function validateFile(file) {
    if (!file) {
        console.log('no file found');
        throw new Error('no file provided');
    }
    if (/'/.test(file.name)) {
        console.log('file name had apostrophe in it');
        throw new Error('apostrophes are not allowed in the file name');
    }
    // validate size and type
    switch (file.type) {
        case 'image/jpeg':
        case 'image/jpg':
        case 'image/png':
            if (file.size > 10000000){
                console.log('file was too big');
                throw new Error('Sorry, images are limited to 10 megabytes.');
            }
            break;
        case 'image/gif':
            if (file.size > 50000000){
                console.log('file was too big');
                throw new Error('Sorry, .gifs are limited to 50 megabytes.');
            }
            break;
        case 'video/mp4':
            if (file.size > 50000000){
                console.log('file was too big');
                throw new Error('Sorry, videos are limited to 50 megabytes.');
            }
            break;
        default:
            console.log('file type is not supported');
            throw new Error(file.type + ' is not a supported file type. Only, .jpeg, .png, .gif, and .mp4 files are currently supported.')
    }
}
// validation function that checks to make sure the claim name is valid
function validateClaimName (name) {
    // ensure a name was entered
    if (name.length < 1) {
        throw new NameError("You must enter a name for your url");
    }
    // validate the characters in the 'name' field
    const invalidCharacters = /[^A-Za-z0-9,-]/g.exec(name);
    if (invalidCharacters) {
        throw new NameError('"' + invalidCharacters + '" characters are not allowed in the url.');
    }
}

function validateChannelName (name) {
    name = name.substring(name.indexOf('@') + 1);
    // ensure a name was entered
    if (name.length < 1) {
        throw new ChannelNameError("You must enter a name for your channel");
    }
    // validate the characters in the 'name' field
    const invalidCharacters = /[^A-Za-z0-9,-,@]/g.exec(name);
    if (invalidCharacters) {
        throw new ChannelNameError('"' + invalidCharacters + '" characters are not allowed in the channel name.');
    }
}

function validatePassword (password) {
    if (password.length < 1) {
        throw new ChannelPasswordError("You must enter a password for you channel");
    }
}

function cleanseClaimName(name) {
    name = name.replace(/\s+/g, '-'); // replace spaces with dashes
    name = name.replace(/[^A-Za-z0-9-]/g, '');  // remove all characters that are not A-Z, a-z, 0-9, or '-'
    return name;
}

// validation functions to check claim & channel name eligibility as the inputs change

function isNameAvailable (name, apiUrl) {
    const url = apiUrl + name;
    return getRequest(url)
}

function showError(errorDisplay, errorMsg) {
    errorDisplay.hidden = false;
    errorDisplay.innerText = errorMsg;
}

function hideError(errorDisplay) {
    errorDisplay.hidden = true;
    errorDisplay.innerText = '';
}

function showSuccess (successElement) {
    successElement.hidden = false;
    successElement.innerHTML = "&#x2714";
}

function hideSuccess (successElement) {
    successElement.hidden = true;
    successElement.innerHTML = "";
}

function checkAvailability(name, successDisplayElement, errorDisplayElement, validateName, isNameAvailable, errorMessage, apiUrl) {
    try {
        // check to make sure the characters are valid
        validateName(name);
        // check to make sure it is available
        isNameAvailable(name, apiUrl)
            .then(result => {
                console.log('result:', result)
                if (result === true) {
                    hideError(errorDisplayElement);
                    showSuccess(successDisplayElement)
                } else {
                    hideSuccess(successDisplayElement);
                    showError(errorDisplayElement, errorMessage);
                }
            })
            .catch(error => {
                hideSuccess(successDisplayElement);
                showError(errorDisplayElement, error.message);
            });
    } catch (error) {
        hideSuccess(successDisplayElement);
        showError(errorDisplayElement, error.message);
    }
}

function checkClaimName(name){
    const successDisplayElement = document.getElementById('input-success-claim-name');
    const errorDisplayElement = document.getElementById('input-error-claim-name');
    checkAvailability(name, successDisplayElement, errorDisplayElement, validateClaimName, isNameAvailable, 'Sorry, that url ending has been taken', '/api/isClaimAvailable/');
}

function checkChannelName(name){
    const successDisplayElement = document.getElementById('input-success-channel-name');
    const errorDisplayElement = document.getElementById('input-error-channel-name');
    name = `@${name}`;
    checkAvailability(name, successDisplayElement, errorDisplayElement, validateChannelName, isNameAvailable, 'Sorry, that Channel name has been taken by another user', '/api/isChannelAvailable/');
}

// validation function which checks all aspects of the publish submission
function validateFilePublishSubmission(stagedFiles, claimName, channelName){
    console.log(`validating publish submission > name: ${claimName} channel: ${channelName} file:`, stagedFiles);
    return new Promise(function (resolve, reject) {
        // 1. make sure 1 file was staged
        if (!stagedFiles) {
            reject(new FileError("Please select a file"));
            return;
        } else if (stagedFiles.length > 1) {
            reject(new FileError("Only one file is allowed at a time"));
            return;
        }
        // 2. validate the file's name, type, and size
        try {
            validateFile(stagedFiles[0]);
        } catch (error) {
            reject(error);
            return;
        }
        // 3. validate that a channel was chosen
        if (channelName === 'new' || channelName === 'login') {
            reject(new ChannelNameError("Please log in to a channel"));
            return;
        };
        // 4. validate the claim name
        try {
            validateClaimName(claimName);
        } catch (error) {
            reject(error);
            return;
        }
        // if all validation passes, check availability of the name (note: do we need to re-validate channel name vs. credentials as well?)
        return isNameAvailable(claimName, '/api/isClaimAvailable/')
            .then(result => {
                if (result) {
                    resolve();
                } else {
                    reject(new NameError('that url ending is already taken'));
                }
            })
            .catch(error => {
                reject(error);
            });
    });
}

// validation function which checks all aspects of a new channel submission
function validateNewChannelSubmission(userName, password){
    const channelName = `@${userName}`;
    return new Promise(function (resolve, reject) {
        // 1. validate name
        try {
            validateChannelName(channelName);
        } catch (error) {
            return reject(error);
        }
        // 2. validate password
        try {
            validatePassword(password);
        } catch (error) {
            return reject(error);
        }
        // 3. if all validation passes, check availability of the name
        isNameAvailable(channelName, '/api/isChannelAvailable/')  // validate the availability
            .then(result => {
                if (result) {
                    console.log('channel is available');
                    resolve();
                } else {
                    console.log('channel is not available');
                    reject(new ChannelNameError('that channel name has already been taken'));
                }
            })
            .catch( error => {
                console.log('error evaluating channel name availability', error);
                reject(error);
            });
    });
}