// Copyright (c) 2022 Marceline Cramer
// SPDX-License-Identifier: LGPL-3.0-or-later

pub use canary_script::*;
use parking_lot::{Mutex, RwLock};
use slab::Slab;
use std::collections::HashMap;
use std::sync::Arc;

pub mod backend;
pub mod text;

use backend::{Backend, Instance, ScriptAbi};
use text::FontStore;

/// The main interface to Canary.
pub struct Runtime {
    backend: Box<dyn Backend>,
    font_store: Arc<FontStore>,
}

impl Runtime {
    pub fn new(backend: Box<dyn Backend>) -> anyhow::Result<Self> {
        Ok(Self {
            backend,
            font_store: Arc::new(FontStore::new()),
        })
    }

    pub fn load_module(&self, module: &[u8]) -> anyhow::Result<Script> {
        let abi = ScriptAbi::new(self.font_store.to_owned());
        let abi = Arc::new(abi);
        let instance = self.backend.load_module(abi.to_owned(), module)?;

        Ok(Script {
            instance,
            abi,
        })
    }
}

/// A loaded instance of a Canary script.
pub struct Script {
    instance: Arc<dyn Instance>,
    abi: Arc<ScriptAbi>,
}

impl Script {
    pub fn create_panel(&mut self, protocol: &str, msg: Vec<u8>) -> anyhow::Result<Panel> {
        let id = self.abi.create_panel();
        let userdata = self.instance.bind_panel(id, protocol, msg);
        Ok(Panel {
            instance: self.instance.clone(),
            abi: self.abi.clone(),
            id,
            userdata,
        })
    }
}

/// A Canary panel.
pub struct Panel {
    instance: Arc<dyn Instance>,
    abi: Arc<ScriptAbi>,
    id: PanelId,
    userdata: u32,
}

impl Panel {
    pub fn update(&self, dt: f32) {
        self.instance.update(self.userdata, dt);
    }

    pub fn draw(&self) -> Vec<DrawCommand> {
        self.instance.draw(self.userdata)
    }

    pub fn on_resize(&self, new_size: Vec2) {
        self.instance.on_resize(self.userdata, new_size);
    }

    pub fn on_cursor_event(&self, kind: CursorEventKind, at: Vec2) {
        self.instance.on_cursor_event(self.userdata, kind, at);
    }

    pub fn on_message(&self, msg: Vec<u8>) {
        self.instance.on_message(self.userdata, msg);
    }

    pub fn recv_messages(&self) -> Vec<Vec<u8>> {
        self.abi.recv_panel_messages(self.id)
    }
}

/// Proportion constant between pixels (at 96dpi) to millimeters (Canary's unit measurement).
pub const PX_PER_MM: f32 = 25.4 / 96.0;

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct PanelId(pub(crate) usize);

#[non_exhaustive]
#[derive(Clone, Debug)]
pub enum DrawCommand {
    Mesh {
        vertices: Vec<MeshVertex>,
        indices: Vec<MeshIndex>,
    },
}