//! `workspace/executeCommand` dispatcher.
//!
//! Phase 13 lands the router + the first command. Phases 14–17 register
//! their own commands here. Each handler returns the `WorkspaceEdit` it
//! wants applied; the `Backend` calls `client.apply_edit` after the call.
//!
//! Phase 13 surface:
//!   - `nuwiki.file.delete` — args: `{ "uri": <Url> }`

use serde::Deserialize;
use tower_lsp::lsp_types::{Url, WorkspaceEdit};

use crate::edits::{op_delete, WorkspaceEditBuilder};
use crate::Backend;

/// All commands the server advertises in `ExecuteCommandOptions.commands`.
/// Keep this in lock-step with the match arms in `execute` below — adding
/// here without a handler will fail at runtime; adding a handler without
/// listing here means the client won't see it as available.
pub const COMMANDS: &[&str] = &["nuwiki.file.delete"];

/// Dispatch an `executeCommand` request. Returns `Ok(None)` for commands
/// that don't produce a `WorkspaceEdit` (e.g. read-only queries); returns
/// `Err` with a human-readable message for unknown commands or bad args
/// — the LSP backend logs it and returns `null` to the client.
pub(crate) async fn execute(
    _backend: &Backend,
    command: &str,
    args: Vec<serde_json::Value>,
) -> Result<Option<WorkspaceEdit>, String> {
    match command {
        "nuwiki.file.delete" => file_delete(args),
        other => Err(format!("unknown nuwiki command: {other}")),
    }
}

fn file_delete(args: Vec<serde_json::Value>) -> Result<Option<WorkspaceEdit>, String> {
    #[derive(Deserialize)]
    struct Args {
        uri: Url,
    }
    let raw = args
        .into_iter()
        .next()
        .ok_or_else(|| "nuwiki.file.delete: missing arguments".to_string())?;
    let parsed: Args = serde_json::from_value(raw)
        .map_err(|e| format!("nuwiki.file.delete: invalid args — {e}"))?;
    let mut builder = WorkspaceEditBuilder::new();
    builder.file_op(op_delete(parsed.uri));
    Ok(Some(builder.build()))
}