pub const RENDER_IMAGE: u32 = 1 << 0;
pub const RENDER_VIDEO: u32 = 1 << 1;
pub const RENDER_AUDIO: u32 = 1 << 2;
pub const RENDER_MARKDOWN: u32 = 1 << 3;
pub const RENDER_TEXT: u32 = 1 << 4;
pub const RENDER_DOCUMENT: u32 = 1 << 5;
pub const RENDER_EXECUTABLE: u32 = 1 << 6;
pub const RENDER_DANGEROUS: u32 = 1 << 7;
pub const RENDER_NO_INLINE: u32 = 1 << 8;

const DANGEROUS_EXTENSIONS: &[&str] = &[
    "exe", "scr", "bat", "cmd", "sh", "dll", "so", "dylib", "jar", "msi", "com", "app", "apk",
];

const DANGEROUS_MIME_TYPES: &[&str] = &[
    "text/html",
    "text/javascript",
    "text/css",
    "application/javascript",
    "application/ecmascript",
];

pub fn detect_mime_type(data: &[u8], file_name: &str) -> String {
    if let Some(kind) = infer::get(data) {
        let mime = kind.mime_type();
        if !mime.is_empty() && mime != "application/octet-stream" {
            return mime.to_string();
        }
    }
    mime_guess::from_path(file_name)
        .first_or_octet_stream()
        .to_string()
}

pub fn compute_render_flags(mime_type: &str, file_name: &str, data: &[u8]) -> u32 {
    let mut flags = 0u32;

    if mime_type.starts_with("image/") {
        flags |= RENDER_IMAGE;
    } else if mime_type.starts_with("video/") {
        flags |= RENDER_VIDEO;
    } else if mime_type.starts_with("audio/") {
        flags |= RENDER_AUDIO;
    } else if mime_type == "text/markdown"
        || file_name.ends_with(".md")
        || file_name.ends_with(".markdown")
    {
        flags |= RENDER_MARKDOWN | RENDER_TEXT;
    } else if mime_type.starts_with("text/") {
        flags |= RENDER_TEXT;
    } else if mime_type == "application/pdf" || mime_type.starts_with("application/vnd.") {
        flags |= RENDER_DOCUMENT;
    }

    if DANGEROUS_MIME_TYPES.contains(&mime_type) {
        flags |= RENDER_DANGEROUS | RENDER_NO_INLINE;
    }

    let ext = file_name.rsplit('.').next().unwrap_or("").to_lowercase();
    if DANGEROUS_EXTENSIONS.contains(&ext.as_str()) {
        flags |= RENDER_EXECUTABLE | RENDER_DANGEROUS | RENDER_NO_INLINE;
    }

    if let Some(kind) = infer::get(data) {
        let mime = kind.mime_type();
        if mime == "application/x-executable"
            || mime == "application/x-msdownload"
            || mime == "application/x-pie-executable"
        {
            flags |= RENDER_EXECUTABLE | RENDER_DANGEROUS | RENDER_NO_INLINE;
        }
    }

    if flags & (RENDER_EXECUTABLE | RENDER_DANGEROUS) != 0 {
        flags |= RENDER_NO_INLINE;
    }

    flags
}

pub fn is_dangerous(flags: u32) -> bool {
    flags & RENDER_DANGEROUS != 0
}

pub fn should_inline(flags: u32) -> bool {
    flags & RENDER_NO_INLINE == 0
}