use self::refs::DebugInfoRefsMap;
use self::simulate::generate_simulated_dwarf;
use self::unit::clone_unit;
use crate::debug::gc::build_dependencies;
use crate::CompiledFunctions;
use anyhow::Error;
use cranelift_codegen::isa::TargetIsa;
use gimli::{
    write, DebugAddr, DebugLine, DebugLineStr, DebugStr, DebugStrOffsets, LocationLists,
    RangeLists, UnitSectionOffset,
};
use std::collections::HashSet;
use thiserror::Error;
use wasmtime_environ::{DebugInfoData, ModuleMemoryOffset};

pub use address_transform::AddressTransform;

mod address_transform;
mod attr;
mod expression;
mod line_program;
mod range_info_builder;
mod refs;
mod simulate;
mod unit;
mod utils;

pub(crate) trait Reader: gimli::Reader<Offset = usize> {}

impl<'input, Endian> Reader for gimli::EndianSlice<'input, Endian> where Endian: gimli::Endianity {}

#[derive(Error, Debug)]
#[error("Debug info transform error: {0}")]
pub struct TransformError(&'static str);

pub(crate) struct DebugInputContext<'a, R>
where
    R: Reader,
{
    debug_str: &'a DebugStr<R>,
    debug_str_offsets: &'a DebugStrOffsets<R>,
    debug_line_str: &'a DebugLineStr<R>,
    debug_line: &'a DebugLine<R>,
    debug_addr: &'a DebugAddr<R>,
    rnglists: &'a RangeLists<R>,
    loclists: &'a LocationLists<R>,
    reachable: &'a HashSet<UnitSectionOffset>,
}

pub fn transform_dwarf(
    isa: &dyn TargetIsa,
    di: &DebugInfoData,
    funcs: &CompiledFunctions,
    memory_offset: &ModuleMemoryOffset,
) -> Result<write::Dwarf, Error> {
    let addr_tr = AddressTransform::new(funcs, &di.wasm_file);
    let reachable = build_dependencies(&di.dwarf, &addr_tr)?.get_reachable();

    let context = DebugInputContext {
        debug_str: &di.dwarf.debug_str,
        debug_str_offsets: &di.dwarf.debug_str_offsets,
        debug_line_str: &di.dwarf.debug_line_str,
        debug_line: &di.dwarf.debug_line,
        debug_addr: &di.dwarf.debug_addr,
        rnglists: &di.dwarf.ranges,
        loclists: &di.dwarf.locations,
        reachable: &reachable,
    };

    let out_encoding = gimli::Encoding {
        format: gimli::Format::Dwarf32,
        // TODO: this should be configurable
        version: 4,
        address_size: isa.pointer_bytes(),
    };

    let mut out_strings = write::StringTable::default();
    let mut out_units = write::UnitTable::default();

    let out_line_strings = write::LineStringTable::default();
    let mut pending_di_refs = Vec::new();
    let mut di_ref_map = DebugInfoRefsMap::new();

    let mut translated = HashSet::new();
    let mut iter = di.dwarf.debug_info.units();
    while let Some(header) = iter.next().unwrap_or(None) {
        let unit = di.dwarf.unit(header)?;
        if let Some((id, ref_map, pending_refs)) = clone_unit(
            &di.dwarf,
            unit,
            &context,
            &addr_tr,
            funcs,
            memory_offset,
            out_encoding,
            &mut out_units,
            &mut out_strings,
            &mut translated,
            isa,
        )? {
            di_ref_map.insert(&header, id, ref_map);
            pending_di_refs.push((id, pending_refs));
        }
    }
    di_ref_map.patch(pending_di_refs.into_iter(), &mut out_units);

    generate_simulated_dwarf(
        &addr_tr,
        di,
        memory_offset,
        funcs,
        &translated,
        out_encoding,
        &mut out_units,
        &mut out_strings,
        isa,
    )?;

    Ok(write::Dwarf {
        units: out_units,
        line_programs: vec![],
        line_strings: out_line_strings,
        strings: out_strings,
    })
}