use fidl::unpersist;
use fidl_cf_sc_internal_elementlauncherconfig::Config as FidlConfig;
use fuchsia_inspect::Node;
use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
use fuchsia_zircon as zx;
#[derive(Debug)]
pub struct Config {
    pub main_element_url: String,
}
impl Config {
    pub fn take_from_startup_handle() -> Self {
        let config_vmo: zx::Vmo =
            take_startup_handle(HandleInfo::new(HandleType::ComponentConfigVmo, 0))
                .expect("Config VMO handle must be provided and cannot already have been taken.")
                .into();
        let config_size =
            config_vmo.get_content_size().expect("must be able to read config vmo content size");
        assert_ne!(config_size, 0, "config vmo must be non-empty");
        let mut config_bytes = Vec::new();
        config_bytes.resize(config_size as usize, 0);
        config_vmo.read(&mut config_bytes, 0).expect("must be able to read config vmo");
        let checksum_length = u16::from_le_bytes([config_bytes[0], config_bytes[1]]) as usize;
        let fidl_start = 2 + checksum_length;
        let observed_checksum = &config_bytes[2..fidl_start];
        let expected_checksum = vec![
            0xb4, 0x56, 0x03, 0x83, 0xa0, 0x57, 0x78, 0x7e, 0x98, 0x97, 0xc1, 0xa8, 0xde, 0x30,
            0x08, 0x64, 0x01, 0x5d, 0x41, 0x72, 0xd4, 0x8c, 0x8d, 0x97, 0x2f, 0x40, 0x1e, 0x25,
            0xd4, 0x65, 0x8c, 0x3a,
        ];
        assert_eq!(
            observed_checksum, expected_checksum,
            "checksum from config VMO does not match expected checksum"
        );
        let fidl_config: FidlConfig = unpersist(&config_bytes[fidl_start..])
            .expect("must be able to parse bytes as config FIDL");
        Self { main_element_url: fidl_config.main_element_url }
    }
    pub fn record_inspect(&self, inspector_node: &Node) {
        inspector_node.record_string("main_element_url", &self.main_element_url);
    }
}