//! Host-side IPC request handler.

use crate::host::HostApi;
use crate::ipc::protocol::{PluginRequest, PluginResponse};

fn addressable_document_snapshot(host: &dyn HostApi) -> codec::CadDocument {
    let mut snapshot = host.document().clone();
    let attributes = host
        .document()
        .entities()
        .filter_map(|entity| match entity {
            codec::EntityType::Insert(insert) => Some(insert.attributes.clone()),
            _ => None,
        })
        .flatten()
        .map(codec::EntityType::AttributeEntity)
        .collect::<Vec<_>>();
    for attribute in attributes {
        // Attribute entities remain canonical children of INSERT in the host
        // document.  The IPC snapshot also indexes them by handle so plugin
        // document models can address a child exactly like any other entity.
        let _ = snapshot.add_entity(attribute);
    }
    snapshot
}

/// Apply one plugin request to the host's `HostApi` implementation.
///
/// `on_start_interactive` is called when the plugin starts an interactive
/// command; the host should install an adapter that sends
/// `HostRequest::InteractiveEvent` back to the plugin process.
pub fn handle_plugin_request(
    host: &mut dyn HostApi,
    req: PluginRequest,
    on_start_interactive: &mut dyn FnMut(u64),
) -> PluginResponse {
    use PluginRequest::*;
    match req {
        PushInfo(msg) => {
            host.push_info(&msg);
            PluginResponse::Ok
        }
        PushOutput(msg) => {
            host.push_output(&msg);
            PluginResponse::Ok
        }
        PushError(msg) => {
            host.push_error(&msg);
            PluginResponse::Ok
        }
        AddEntity(entity) => PluginResponse::Handle(host.add_entity(entity)),
        AddEntities(entities) => PluginResponse::Handles(host.add_entities(entities)),
        UpdateEntity(entity) => PluginResponse::Bool(host.update_entity(entity)),
        RemoveEntity { handle } => PluginResponse::Bool(host.remove_entity(handle)),
        BumpGeometry => {
            host.bump_geometry();
            PluginResponse::Ok
        }
        ReadRecord { handle, app_name } => {
            PluginResponse::Record(host.read_record(handle, &app_name).cloned())
        }
        WriteRecord { handle, record } => PluginResponse::Bool(host.write_record(handle, record)),
        RemoveRecord { handle, app_name } => {
            PluginResponse::Bool(host.remove_record(handle, &app_name))
        }
        PushUndo { label } => {
            host.push_undo(&label);
            PluginResponse::Ok
        }
        SetDirty => {
            host.set_dirty();
            PluginResponse::Ok
        }
        StartInteractive { command_id } => {
            on_start_interactive(command_id);
            PluginResponse::Ok
        }
        DocumentSnapshot => PluginResponse::Document(Box::new(addressable_document_snapshot(host))),
        OpenDocumentView => match host.document_view() {
            Some(info) => PluginResponse::DocumentView {
                path: info.path,
                version: info.version,
            },
            None => PluginResponse::Error("shared document view unavailable".to_string()),
        },
        OpenDocumentViewV4 { tab_id } => match host.document_view_v4(tab_id) {
            Some(info) => PluginResponse::DocumentViewV4 {
                path: info.path,
                version: info.version,
            },
            None => PluginResponse::Error("V4 shared document view unavailable".to_string()),
        },
        CloseDocumentViewV4 { tab_id } => {
            host.close_document_view_v4(tab_id);
            PluginResponse::Ok
        }
        GetTabId => PluginResponse::TabId(host.tab_id()),
        DocumentPath { tab_id } => PluginResponse::DocumentPath(
            host.document_path(tab_id).map(|path| path.into_os_string()),
        ),
        AddLayer(config) => PluginResponse::OptHandle(host.add_layer(config)),
        ModifyLayer(config) => PluginResponse::Bool(host.modify_layer(config)),
        ExecuteCommand(cmd) => PluginResponse::Bool(host.execute_command(&cmd)),
        GetSystemVariable { name } => PluginResponse::SystemVariable(host.system_variable(&name)),
        SetSystemVariable { name, value } => {
            PluginResponse::SystemVariableResult(host.set_system_variable(&name, value))
        }
        UpdateEntitiesTransaction { label, entities } => PluginResponse::EntityTransactionResult(
            host.update_entities_transaction(&label, entities),
        ),
        GetSelection => PluginResponse::Selection(host.selection()),
        SetSelection { handles } => PluginResponse::SelectionResult(host.set_selection(&handles)),
        SolidOperation { operation } => PluginResponse::SolidResult(host.solid_operation(operation)),
        TableOperation { operation } => PluginResponse::TableResult(host.table_operation(operation)),
        RunCommand { request } => PluginResponse::CommandResult(host.run_command(request)),
    }
}