module main

import os

const default_avatar_name = 'default_avatar.png'
const assets_path = 'assets'
const avatar_max_file_size = 1 * 1024 * 1024 // 1 megabyte

const supported_mime_types = [
    'image/jpeg',
    'image/png',
    'image/webp',
]

fn validate_avatar_content_type(content_type string) bool {
    return supported_mime_types.contains(content_type)
}

fn extract_file_extension_from_mime_type(mime_type string) !string {
    is_valid_mime_type := validate_avatar_content_type(mime_type)

    if !is_valid_mime_type {
        return error('MIME type is not supported')
    }

    mime_parts := mime_type.split('/')

    return mime_parts[1]
}

fn validate_avatar_file_size(content string) bool {
    return content.len <= avatar_max_file_size
}

fn (app App) build_avatar_file_path(avatar_filename string) string {
    relative_path := os.join_path(app.config.avatars_path, avatar_filename)

    return os.abs_path(relative_path)
}

fn (app App) build_avatar_file_url(avatar_filename string) string {
    clean_path := app.config.avatars_path.trim_string_left('./')
    return os.join_path('/', clean_path, avatar_filename)
}

fn (app App) write_user_avatar(avatar_filename string, file_content string) bool {
    path := os.join_path(app.config.avatars_path, avatar_filename)

    os.write_file(path, file_content) or { return false }

    return true
}

fn (app App) prepare_user_avatar_url(avatar_filename_or_url string) string {
    is_url := avatar_filename_or_url.starts_with('http')
    is_default_avatar := avatar_filename_or_url == default_avatar_name
    if is_url {
        return avatar_filename_or_url
    }
    if is_default_avatar {
        return os.join_path('/', assets_path, avatar_filename_or_url)
    }
    return app.build_avatar_file_url(avatar_filename_or_url)
}