use crate::collections::*;
use crate::protocol::*;

use super::visitor::*;

// Will get a rename. Will probably become bytecode emitter or something. For
// now it just scans the scopes and assigns a unique number for each variable
// such that, at any point in the program's execution, all accessible in-scope
// variables will have a unique position "on the stack".
pub(crate) struct PassStackSize {
    definition_buffer: ScopedBuffer<DefinitionId>,
}

impl PassStackSize {
    pub(crate) fn new() -> Self {
        return Self{
            definition_buffer: ScopedBuffer::with_capacity(BUFFER_INIT_CAP_LARGE),
        }
    }
}

impl Visitor for PassStackSize {
    fn visit_module(&mut self, ctx: &mut Ctx) -> VisitorResult {
        let module = ctx.module();
        debug_assert_eq!(module.phase, ModuleCompilationPhase::Rewritten);

        let root_id = module.root_id;
        let root = &ctx.heap[root_id];
        let definition_section = self.definition_buffer.start_section_initialized(&root.definitions);
        for definition_index in 0..definition_section.len() {
            let definition_id = definition_section[definition_index];
            self.visit_definition(ctx, definition_id)?
        }

        definition_section.forget();
        // ctx.module_mut().phase = ModuleCompilationPhase::StackSizeStuffAndStuff;
        return Ok(())
    }
}