// A module for searching for libraries
// FIXME: I'm not happy how this module turned out. Should probably
// just be folded into cstore.

import std::{fs, os, generic_os};

export filesearch;
export mk_filesearch;
export pick;
export pick_file;
export search;
export relative_target_lib_path;
export get_cargo_root;
export get_cargo_root_nearest;
export libdir;

type pick<T> = fn(path: fs::path) -> option<T>;

fn pick_file(file: fs::path, path: fs::path) -> option<fs::path> {
    if fs::basename(path) == file { option::some(path) }
    else { option::none }
}

iface filesearch {
    fn sysroot() -> fs::path;
    fn lib_search_paths() -> [fs::path];
    fn get_target_lib_path() -> fs::path;
    fn get_target_lib_file_path(file: fs::path) -> fs::path;
}

fn mk_filesearch(maybe_sysroot: option<fs::path>,
                 target_triple: str,
                 addl_lib_search_paths: [fs::path]) -> filesearch {
    type filesearch_impl = {sysroot: fs::path,
                            addl_lib_search_paths: [fs::path],
                            target_triple: str};
    impl of filesearch for filesearch_impl {
        fn sysroot() -> fs::path { self.sysroot }
        fn lib_search_paths() -> [fs::path] {
            self.addl_lib_search_paths
                + [make_target_lib_path(self.sysroot, self.target_triple)]
                + alt get_cargo_lib_path_nearest() {
                  result::ok(p) { [p] }
                  result::err(p) { [] }
                }
                + alt get_cargo_lib_path() {
                  result::ok(p) { [p] }
                  result::err(p) { [] }
                }
        }
        fn get_target_lib_path() -> fs::path {
            make_target_lib_path(self.sysroot, self.target_triple)
        }
        fn get_target_lib_file_path(file: fs::path) -> fs::path {
            fs::connect(self.get_target_lib_path(), file)
        }
    }

    let sysroot = get_sysroot(maybe_sysroot);
    #debug("using sysroot = %s", sysroot);
    {sysroot: sysroot,
     addl_lib_search_paths: addl_lib_search_paths,
     target_triple: target_triple} as filesearch
}

// FIXME #1001: This can't be an obj method
fn search<T: copy>(filesearch: filesearch, pick: pick<T>) -> option<T> {
    for lib_search_path in filesearch.lib_search_paths() {
        #debug("searching %s", lib_search_path);
        for path in fs::list_dir(lib_search_path) {
            #debug("testing %s", path);
            let maybe_picked = pick(path);
            if option::is_some(maybe_picked) {
                #debug("picked %s", path);
                ret maybe_picked;
            } else {
                #debug("rejected %s", path);
            }
        }
    }
    ret option::none;
}

fn relative_target_lib_path(target_triple: str) -> [fs::path] {
    [libdir(), "rustc", target_triple, libdir()]
}

fn make_target_lib_path(sysroot: fs::path,
                        target_triple: str) -> fs::path {
    let path = [sysroot] + relative_target_lib_path(target_triple);
    check vec::is_not_empty(path);
    let path = fs::connect_many(path);
    ret path;
}

fn get_default_sysroot() -> fs::path {
    alt os::get_exe_path() {
      option::some(p) { fs::normalize(fs::connect(p, "..")) }
      option::none {
        fail "can't determine value for sysroot";
      }
    }
}

fn get_sysroot(maybe_sysroot: option<fs::path>) -> fs::path {
    alt maybe_sysroot {
      option::some(sr) { sr }
      option::none { get_default_sysroot() }
    }
}

fn get_cargo_root() -> result::t<fs::path, str> {
    alt generic_os::getenv("CARGO_ROOT") {
        some(_p) { result::ok(_p) }
        none {
          alt fs::homedir() {
            some(_q) { result::ok(fs::connect(_q, ".cargo")) }
            none { result::err("no CARGO_ROOT or home directory") }
          }
        }
    }
}

fn get_cargo_root_nearest() -> result::t<fs::path, str> {
    result::chain(get_cargo_root()) { |p|
        let cwd = os::getcwd();
        let dirname = fs::dirname(cwd);
        let dirpath = fs::split(dirname);
        let cwd_cargo = fs::connect(cwd, ".cargo");
        let par_cargo = fs::connect(dirname, ".cargo");

        // FIXME: this duplicates lib path
        if cwd_cargo == p {
            ret result::ok(p);
        }

        while vec::is_not_empty(dirpath) && par_cargo != p {
            if fs::path_is_dir(par_cargo) {
                ret result::ok(par_cargo);
            }
            vec::pop(dirpath);
            dirname = fs::dirname(dirname);
            par_cargo = fs::connect(dirname, ".cargo");
        }

        result::ok(cwd_cargo)
    }
}

fn get_cargo_lib_path() -> result::t<fs::path, str> {
    result::chain(get_cargo_root()) { |p|
        result::ok(fs::connect(p, libdir()))
    }
}

fn get_cargo_lib_path_nearest() -> result::t<fs::path, str> {
    result::chain(get_cargo_root_nearest()) { |p|
        result::ok(fs::connect(p, libdir()))
    }
}

// The name of the directory rustc expects libraries to be located.
// On Unix should be "lib", on windows "bin"
fn libdir() -> str {
   let libdir = #env("CFG_LIBDIR");
   if str::is_empty(libdir) {
      fail "rustc compiled without CFG_LIBDIR environment variable";
   }
   libdir
}