//! Shared tool context: the database handle and the fixed desktop user.
//!
//! go-mcp is a peer writer against the same `goingson.db` the desktop app uses.
//! Every write flows through the normal repository layer, so the 33 SQL sync
//! triggers fire and a running GoingsOn picks the changes up. There is no back
//! door around the changelog.

use std::path::PathBuf;

use goingson_core::UserId;
use goingson_db_sqlite::{SqliteProjectRepository, SqliteTaskRepository};
use sqlx::SqlitePool;
use uuid::Uuid;

/// Fixed single-user desktop id. Must match `DESKTOP_USER_ID` in the GoingsOn
/// Tauri app (`src-tauri/src/state.rs`); tasks are keyed on it, so a mismatch
/// would write rows the app never shows.
pub const DESKTOP_USER_ID: UserId = UserId::from_uuid(Uuid::from_u128(1));

/// Everything a tool needs to reach the database. Cheap to clone (the pool is
/// an `Arc` internally); tools hold it behind an `Arc` anyway.
pub struct Ctx {
    pub pool: SqlitePool,
    pub user_id: UserId,
}

impl Ctx {
    pub fn new(pool: SqlitePool) -> Self {
        Self {
            pool,
            user_id: DESKTOP_USER_ID,
        }
    }

    pub fn tasks(&self) -> SqliteTaskRepository {
        SqliteTaskRepository::new(self.pool.clone())
    }

    pub fn projects(&self) -> SqliteProjectRepository {
        SqliteProjectRepository::new(self.pool.clone())
    }
}

/// Default location of `goingson.db`, matching Tauri's `app_data_dir` for the
/// `com.goingson.app` bundle. Resolves the same path the desktop app opens so
/// `go-mcp` with no `--db` flag targets the real database.
pub fn default_db_path() -> Option<PathBuf> {
    let home = std::env::var_os("HOME")?;
    let home = PathBuf::from(home);

    #[cfg(target_os = "macos")]
    let base = home.join("Library/Application Support");

    #[cfg(not(target_os = "macos"))]
    let base = std::env::var_os("XDG_DATA_HOME")
        .map(PathBuf::from)
        .unwrap_or_else(|| home.join(".local/share"));

    Some(base.join("com.goingson.app").join("goingson.db"))
}