use std::net::IpAddr;

use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
#[serde(default)]
pub struct AdminConfig {
    pub enabled: Option<bool>,
    pub bind_addr: Option<String>,
    pub port: Option<u16>,
    pub grpc_port: Option<u16>,
    #[serde(default, deserialize_with = "string_or_vec")]
    pub grpc_trusted_keys: Vec<String>,
    pub cors_allow_origins: Vec<String>,
    pub cors_allow_credentials: Option<bool>,
}

fn string_or_vec<'de, D>(deserializer: D) -> Result<Vec<String>, D::Error>
where
    D: serde::Deserializer<'de>,
{
    #[derive(Deserialize)]
    #[serde(untagged)]
    enum StringOrVec {
        String(String),
        Vec(Vec<String>),
    }

    Ok(match StringOrVec::deserialize(deserializer)? {
        StringOrVec::String(value) => value
            .split(',')
            .map(str::trim)
            .filter(|value| !value.is_empty())
            .map(str::to_string)
            .collect(),
        StringOrVec::Vec(values) => values,
    })
}

impl AdminConfig {
    pub fn enabled(&self) -> bool {
        self.enabled.unwrap_or(true)
    }

    pub fn bind_addr(&self) -> &str {
        self.bind_addr.as_deref().unwrap_or("0.0.0.0")
    }

    pub fn port(&self) -> u16 {
        self.port.unwrap_or(3004)
    }

    pub fn grpc_port(&self) -> u16 {
        self.grpc_port.unwrap_or(3014)
    }

    pub fn grpc_trusted_keys(&self) -> &[String] {
        &self.grpc_trusted_keys
    }

    pub fn cors_allow_credentials(&self) -> bool {
        self.cors_allow_credentials.unwrap_or(false)
    }

    pub fn is_valid(&self) -> Result<(), String> {
        if !self.enabled() {
            return Ok(());
        }
        let bind = self.bind_addr();
        if bind.parse::<IpAddr>().is_err() {
            return Err(format!("admin.bind_addr is not a valid IP: {bind:?}"));
        }
        if self.port == Some(0) {
            return Err("admin.port must be greater than 0".to_string());
        }
        if self.grpc_port == Some(0) {
            return Err("admin.grpc_port must be greater than 0".to_string());
        }
        for origin in &self.cors_allow_origins {
            if !origin.starts_with("http://") && !origin.starts_with("https://") {
                return Err(format!(
                    "admin.cors_allow_origins entry must be an origin URL: {origin:?}"
                ));
            }
        }
        Ok(())
    }
}