//! `memoryd` configuration: read `memoryd.toml` into a typed `Config` (M5a spec, section 11).
//!
//! Unknown keys are errors in every table, as in the other roles: a misspelt key that silently
//! fell back to its default would be a setting the owner believes is set and is not.

use std::path::{Path, PathBuf};

use bxcore::DataClass;
use serde::Deserialize;

#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
#[serde(deny_unknown_fields, default)]
pub struct Paths {
    pub home: PathBuf,
}

impl Default for Paths {
    fn default() -> Self {
        Self {
            home: std::env::var_os("BOXMAKER_HOME")
                .map(PathBuf::from)
                .unwrap_or_else(|| PathBuf::from("/var/lib/boxmaker")),
        }
    }
}

/// `[memory]`: the starter `soul.md`, and whether identity writes wait for the owner.
#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
#[serde(deny_unknown_fields, default)]
pub struct Memory {
    /// A relative path is resolved next to the config file by `Config::load`.
    pub soul_starter: PathBuf,
    pub review: bool,
}

impl Default for Memory {
    fn default() -> Self {
        Self {
            soul_starter: PathBuf::from("soul.md"),
            review: false,
        }
    }
}

/// `[index]`: records above `max_class` are not indexed.
#[derive(Debug, Clone, PartialEq, Eq, Deserialize)]
#[serde(deny_unknown_fields, default)]
pub struct Index {
    pub max_class: DataClass,
}

impl Default for Index {
    fn default() -> Self {
        Self {
            max_class: DataClass::Private,
        }
    }
}

/// An empty path means "the default under `home`".
#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Default)]
#[serde(deny_unknown_fields, default)]
pub struct Sockets {
    #[serde(rename = "loop")]
    pub loopd: PathBuf,
    pub broker: PathBuf,
    pub admin: PathBuf,
}

#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Default)]
#[serde(deny_unknown_fields, default)]
pub struct Config {
    pub paths: Paths,
    pub memory: Memory,
    pub index: Index,
    pub sockets: Sockets,
}

#[derive(Debug)]
pub enum ConfigError {
    Read(PathBuf, std::io::Error),
    Parse(PathBuf, toml::de::Error),
}

impl std::fmt::Display for ConfigError {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        match self {
            ConfigError::Read(path, err) => write!(f, "{}: {err}", path.display()),
            ConfigError::Parse(path, err) => write!(f, "{}: {err}", path.display()),
        }
    }
}

impl std::error::Error for ConfigError {}

impl Config {
    pub fn parse(text: &str) -> Result<Config, toml::de::Error> {
        toml::from_str(text)
    }

    /// Read and parse `path`; a relative `soul_starter` is taken to be next to it.
    pub fn load(path: &Path) -> Result<Config, ConfigError> {
        let text =
            std::fs::read_to_string(path).map_err(|e| ConfigError::Read(path.to_path_buf(), e))?;
        let mut config =
            Config::parse(&text).map_err(|e| ConfigError::Parse(path.to_path_buf(), e))?;
        if config.memory.soul_starter.is_relative() {
            let base = path.parent().unwrap_or_else(|| Path::new("."));
            config.memory.soul_starter = base.join(&config.memory.soul_starter);
        }
        Ok(config)
    }

    fn socket(&self, set: &Path, default: &str) -> PathBuf {
        if set.as_os_str().is_empty() {
            self.paths.home.join(default)
        } else {
            set.to_path_buf()
        }
    }

    pub fn loop_socket(&self) -> PathBuf {
        self.socket(&self.sockets.loopd, "run/loop-memory/memory.sock")
    }
    pub fn broker_socket(&self) -> PathBuf {
        self.socket(&self.sockets.broker, "run/broker-memory/memory.sock")
    }
    pub fn admin_socket(&self) -> PathBuf {
        self.socket(&self.sockets.admin, "run/owner-memory/admin.sock")
    }
    pub fn memory_dir(&self) -> PathBuf {
        self.paths.home.join("memory")
    }
    pub fn index_path(&self) -> PathBuf {
        self.paths.home.join("index/memory.sqlite3")
    }
    pub fn sessions_dir(&self) -> PathBuf {
        self.paths.home.join("sessions")
    }
}