use serde::Deserialize;
use std::path::Path;

/// Configuration for the Matrix bot, read from `.story_kit/bot.toml`.
#[derive(Deserialize, Clone, Debug)]
pub struct BotConfig {
    /// Matrix homeserver URL, e.g. `https://matrix.example.com`
    pub homeserver: String,
    /// Bot user ID, e.g. `@storykit:example.com`
    pub username: String,
    /// Bot password
    pub password: String,
    /// Matrix room ID to join, e.g. `!roomid:example.com`
    pub room_id: String,
    /// Set to `true` to enable the bot (default: false)
    #[serde(default)]
    pub enabled: bool,
    /// Matrix user IDs allowed to interact with the bot.
    /// If empty or omitted, the bot ignores ALL messages (fail-closed).
    #[serde(default)]
    pub allowed_users: Vec<String>,
    /// Previously used to select an Anthropic model. Now ignored — the bot
    /// uses Claude Code which manages its own model selection. Kept for
    /// backwards compatibility so existing bot.toml files still parse.
    #[allow(dead_code)]
    pub model: Option<String>,
}

impl BotConfig {
    /// Load bot configuration from `.story_kit/bot.toml`.
    ///
    /// Returns `None` if the file does not exist, fails to parse, or has
    /// `enabled = false`.
    pub fn load(project_root: &Path) -> Option<Self> {
        let path = project_root.join(".story_kit").join("bot.toml");
        if !path.exists() {
            return None;
        }
        let content = std::fs::read_to_string(&path)
            .map_err(|e| eprintln!("[matrix-bot] Failed to read bot.toml: {e}"))
            .ok()?;
        let config: BotConfig = toml::from_str(&content)
            .map_err(|e| eprintln!("[matrix-bot] Invalid bot.toml: {e}"))
            .ok()?;
        if !config.enabled {
            return None;
        }
        Some(config)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;

    #[test]
    fn load_returns_none_when_file_missing() {
        let tmp = tempfile::tempdir().unwrap();
        let result = BotConfig::load(tmp.path());
        assert!(result.is_none());
    }

    #[test]
    fn load_returns_none_when_disabled() {
        let tmp = tempfile::tempdir().unwrap();
        let sk = tmp.path().join(".story_kit");
        fs::create_dir_all(&sk).unwrap();
        fs::write(
            sk.join("bot.toml"),
            r#"
homeserver = "https://matrix.example.com"
username = "@bot:example.com"
password = "secret"
room_id = "!abc:example.com"
enabled = false
"#,
        )
        .unwrap();
        let result = BotConfig::load(tmp.path());
        assert!(result.is_none());
    }

    #[test]
    fn load_returns_config_when_enabled() {
        let tmp = tempfile::tempdir().unwrap();
        let sk = tmp.path().join(".story_kit");
        fs::create_dir_all(&sk).unwrap();
        fs::write(
            sk.join("bot.toml"),
            r#"
homeserver = "https://matrix.example.com"
username = "@bot:example.com"
password = "secret"
room_id = "!abc:example.com"
enabled = true
"#,
        )
        .unwrap();
        let result = BotConfig::load(tmp.path());
        assert!(result.is_some());
        let config = result.unwrap();
        assert_eq!(config.homeserver, "https://matrix.example.com");
        assert_eq!(config.username, "@bot:example.com");
        assert_eq!(config.room_id, "!abc:example.com");
        assert!(config.model.is_none());
    }

    #[test]
    fn load_returns_none_when_toml_invalid() {
        let tmp = tempfile::tempdir().unwrap();
        let sk = tmp.path().join(".story_kit");
        fs::create_dir_all(&sk).unwrap();
        fs::write(sk.join("bot.toml"), "not valid toml {{{").unwrap();
        let result = BotConfig::load(tmp.path());
        assert!(result.is_none());
    }

    #[test]
    fn load_respects_optional_model() {
        let tmp = tempfile::tempdir().unwrap();
        let sk = tmp.path().join(".story_kit");
        fs::create_dir_all(&sk).unwrap();
        fs::write(
            sk.join("bot.toml"),
            r#"
homeserver = "https://matrix.example.com"
username = "@bot:example.com"
password = "secret"
room_id = "!abc:example.com"
enabled = true
model = "claude-sonnet-4-6"
"#,
        )
        .unwrap();
        let config = BotConfig::load(tmp.path()).unwrap();
        assert_eq!(config.model.as_deref(), Some("claude-sonnet-4-6"));
    }
}