use std::fmt::Display;

use crate::{common::{Output, Relocatable}, error::Error};

pub struct Linker<'data> {
    relocatables: Vec<Box<dyn Relocatable + 'data>>,
}

impl<'data> Linker<'data> {
    pub fn new(relocatables: Vec<Box<dyn Relocatable + 'data>>) -> Self {
        Self {
            relocatables,
        }
    }

    pub fn add_relocatable(
        &mut self,
        relocatable: Box<dyn Relocatable + 'data>,
    ) {
        self.relocatables.push(relocatable);
    }

    pub fn link(&self, output: &mut dyn Output) -> Result<u64, Error> {
        let allocated = output.allocate(self.total_size()?)?;

        for r in self.relocatables.iter() {
            for s in r.sections() {
                output.append_section(&s?)?;
            }
        }

        Ok(allocated)
    }

    fn total_size(&self) -> Result<u64, Error> {
        let mut result = 0u64;

        for o in self.relocatables.iter() {
            for s in o.sections() {
                result += s?.size()?;
            }
        }

        Ok(result)
    }
}

impl Display for Linker<'_> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(f, "===Relocatables===")?;

        for r in self.relocatables.iter() {
            write!(f, "{}", r)?;
        }

        Ok(())
    }
}