use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use rtic_syntax::ast::App;

use crate::{analyze::Analysis, check::Extra};

mod assertions;
mod dispatchers;
mod hardware_tasks;
mod idle;
mod init;
mod local_resources;
mod shared_resources;
mod local_resources_struct;
mod shared_resources_struct;
mod module;
mod post_init;
mod pre_init;
mod software_tasks;
mod timer_queue;
mod util;

// TODO document the syntax here or in `rtic-syntax`
pub fn app(app: &App, analysis: &Analysis, extra: &Extra) -> TokenStream2 {
    let mut mod_app = vec![];
    let mut mains = vec![];
    let mut root = vec![];
    let mut user = vec![];

    // Generate the `main` function
    let assertion_stmts = assertions::codegen(app, analysis);

    let pre_init_stmts = pre_init::codegen(app, analysis, extra);

    let (mod_app_init, root_init, user_init, call_init) = init::codegen(app, analysis, extra);

    let post_init_stmts = post_init::codegen(app, analysis);

    let (mod_app_idle, root_idle, user_idle, call_idle) = idle::codegen(app, analysis, extra);

    user.push(quote!(
        #user_init

        #user_idle
    ));

    root.push(quote!(
        #(#root_init)*

        #(#root_idle)*
    ));

    mod_app.push(quote!(
        #mod_app_init

        #mod_app_idle
    ));

    let main = util::suffixed("main");
    mains.push(quote!(
        #[doc(hidden)]
        mod rtic_ext {
            use super::*;
            #[no_mangle]
            unsafe extern "C" fn #main() -> ! {
                #(#assertion_stmts)*

                #(#pre_init_stmts)*

                #[inline(never)]
                fn __rtic_init_resources<F>(f: F) where F: FnOnce() {
                    f();
                }

                // Wrap late_init_stmts in a function to ensure that stack space is reclaimed.
                __rtic_init_resources(||{
                    #call_init

                    #(#post_init_stmts)*
                });

                #call_idle
            }
        }
    ));

    let (mod_app_shared_resources, mod_shared_resources) = shared_resources::codegen(app, analysis, extra);
    let (mod_app_local_resources, mod_local_resources) = local_resources::codegen(app, analysis, extra);

    let (mod_app_hardware_tasks, root_hardware_tasks, user_hardware_tasks) =
        hardware_tasks::codegen(app, analysis, extra);

    let (mod_app_software_tasks, root_software_tasks, user_software_tasks) =
        software_tasks::codegen(app, analysis, extra);

    let mod_app_dispatchers = dispatchers::codegen(app, analysis, extra);
    let mod_app_timer_queue = timer_queue::codegen(app, analysis, extra);
    let user_imports = &app.user_imports;
    let user_code = &app.user_code;
    let name = &app.name;
    let device = &extra.device;

    let monotonic_parts: Vec<_> = app
        .monotonics
        .iter()
        .map(|(_, monotonic)| {
            let name = &monotonic.ident;
            let name_str = &name.to_string();
            let ident = util::monotonic_ident(&name_str);
            let ident = util::mark_internal_ident(&ident);
            let panic_str = &format!(
                "Use of monotonic '{}' before it was passed to the runtime",
                name_str
            );
            let doc = &format!(
                "This module holds the static implementation for `{}::now()`",
                name_str
            );

            let default_monotonic = if monotonic.args.default {
                quote!(pub use #name::now;)
            } else {
                quote!()
            };

            quote! {
                #default_monotonic

                #[doc = #doc]
                #[allow(non_snake_case)]
                pub mod #name {

                    /// Read the current time from this monotonic
                    pub fn now() -> rtic::time::Instant<super::super::#name> {
                        rtic::export::interrupt::free(|_| {
                            use rtic::Monotonic as _;
                            use rtic::time::Clock as _;
                            if let Some(m) = unsafe{ super::super::#ident.get_mut_unchecked() } {
                                if let Ok(v) = m.try_now() {
                                    v
                                } else {
                                    unreachable!("Your monotonic is not infallible!")
                                }
                            } else {
                                panic!(#panic_str);
                            }
                        })
                    }
                }
            }
        })
        .collect();

    let monotonics = if !monotonic_parts.is_empty() {
        quote!(
            pub use rtic::Monotonic as _;

            /// Holds static methods for each monotonic.
            pub mod monotonics {
                #(#monotonic_parts)*
            }
        )
    } else {
        quote!()
    };
    let rt_err = util::rt_err_ident();

    quote!(
        /// The RTIC application module
        pub mod #name {
            /// Always include the device crate which contains the vector table
            use #device as #rt_err;

            #monotonics

            #(#user_imports)*

            /// User code from within the module
            #(#user_code)*
            /// User code end

            #(#user)*

            #(#user_hardware_tasks)*

            #(#user_software_tasks)*

            #(#root)*

            #mod_shared_resources

            #mod_local_resources

            #(#root_hardware_tasks)*

            #(#root_software_tasks)*

            /// app module
            #(#mod_app)*

            #(#mod_app_shared_resources)*

            #(#mod_app_local_resources)*

            #(#mod_app_hardware_tasks)*

            #(#mod_app_software_tasks)*

            #(#mod_app_dispatchers)*

            #(#mod_app_timer_queue)*

            #(#mains)*
        }
    )
}