#!/usr/bin/python
#
# Copyright Colin Sherratt 2014

import subprocess
import os.path
import platform

class Module:
    def has_tests(self):
        return os.path.isfile("src/%s/test.rs" % self.name)

    def get_dep(self):
        args = ["rustc", "src/%s/%s" % (self.name, self.ext),
                "--dep-info", ".tmp.txt", "--no-analysis", "--no-trans", "--out-dir=%s" % self.dir]
        subprocess.call(args)
        with open(".tmp.txt", "r") as f:
            return f.read().split("\n")[0]

    def get_name(self):
        args = ["rustc", "--crate-file-name", "src/%s/%s" % (self.name, self.ext)]
        with open(".tmp.txt", "w+") as f:
            subprocess.call(args, stdout=f)
            f.seek(0)
            return f.read().split("\n")[0]

    def collect_flags(self, mods):
        flags = [self.other_flags]
        for m in [mods[name] for name in self.dep_modules]:
            flags += m.collect_flags(mods)
        return flags

    def get_flags(self, mods):
        flags = [self.flags] + self.collect_flags(mods)
        return " ".join(flags) 

    def make_rule(self, mods):
        dep = self.get_dep() + " "
        dep +=  " ".join(mods[m].ename for m in self.dep_modules)
        how = "%s\n\trustc $(RUST_FLAGS) --out-dir=%s %s src/%s/%s\n" % (dep, self.dir, self.get_flags(mods), self.name, self.ext)
        return how

    def make_test_rules(self, mods):
        dep = self.get_dep() + " "
        dep +=  " ".join(mods[m].ename for m in self.dep_modules)
        dep = ": ".join(["test/%s" % self.name, " ".join([self.ename, "src/%s/test.rs" % self.name, dep.split(": ", 2)[1]])])
        how = "%s\n\trustc $(RUST_FLAGS) --test -o test/%s %s src/%s/test.rs\n" % (dep, self.name, self.get_flags(mods), self.name)
        how += "\ntest/.%s.check: test/%s\n" % (self.name, self.name)
        how += "\t./test/%s && touch test/.%s.check\n" % (self.name, self.name)
        return how

class cd:
    """Context manager for changing the current working directory, creating if necessary"""
    def __init__(self, newPath):
        newPath = os.path.abspath(os.path.expandvars(os.path.expanduser(newPath)))
        self.newPath = newPath
        if not os.path.exists(newPath):
            os.makedirs(newPath)

    def __enter__(self):
        self.savedPath = os.getcwd()
        os.chdir(self.newPath)

    def __exit__(self, etype, value, traceback):
        os.chdir(self.savedPath)

class Lib(Module):
    ext = "lib.rs"
    dir = "lib"
    flags = ""
    def __init__(self, name, dep_modules=None, other_flags=""):
        self.name = name
        self.ename = "lib/%s" % self.get_name()
        self.other_flags = other_flags
        if dep_modules:
            self.dep_modules = dep_modules
        else:
            self.dep_modules = []

class Bin(Module):
    ext = "main.rs"
    dir = "bin"
    flags = "-Zlto"
    def __init__(self, name, dep_modules=None, other_flags=""):
        self.name = name
        self.ename = "bin/%s" % self.get_name()
        self.other_flags = other_flags
        if dep_modules:
            self.dep_modules = dep_modules
        else:
            self.dep_modules = []

class LibMakefile(Module):
    ext = ""
    dir = ""
    flags = ""

    def get_name(self):
        return self.name

    def __init__(self, name, path_to_makefile_dir, path_to_output, dep_modules=None, other_flags=""):
        self.name = name
        self.ename = "lib/%s" % self.get_name()
        self.other_flags = other_flags
        self.path_to_makefile_dir = path_to_makefile_dir
        self.path_to_output = path_to_output
        if dep_modules:
            self.dep_modules = dep_modules
        else:
            self.dep_modules = []

    def make_rule(self, mods):
        out  = "%s: %s\n" % (self.ename, self.path_to_makefile_dir + "Makefile")
        out += "\tmake -C %s && cp %s %s\n" % (self.path_to_makefile_dir, self.path_to_output, self.ename)
        return out

class LibCMake(Module):
    ext = ""
    dir = ""
    flags = ""

    def get_name(self):
        return self.name

    def __init__(self, name, path_to_makefile_dir, path_to_output, dep_modules=None, other_flags="", cmake_flags=""):
        self.name = name
        self.ename = "lib/%s" % self.get_name()
        self.other_flags = other_flags
        self.path_to_makefile_dir = path_to_makefile_dir
        self.path_to_output = path_to_output
        self.cmake_flags = cmake_flags
        if dep_modules:
            self.dep_modules = dep_modules
        else:
            self.dep_modules = []

    def make_rule(self, mods):
        out  = "%s:\n" % (self.path_to_makefile_dir + "Makefile")
        out += "\tcd %s && cmake %s .\n\n" % (self.path_to_makefile_dir, self.cmake_flags)
        out += "%s: %s\n" % (self.ename, self.path_to_makefile_dir + "Makefile")
        out += "\tmake -C %s && cp %s %s\n" % (self.path_to_makefile_dir, self.path_to_output, self.ename)
        return out


def write_makefile(modules):
    modules = {m.name: m for m in modules}

    rules = "\n".join(m.make_rule(modules) for m in modules.values()) + "\n"
    rules += "\n".join(m.make_test_rules(modules) for m in modules.values() if m.has_tests())
    all = " ".join(m.ename for m in modules.values())

    with open("Makefile", "w+") as f:
        f.write("RUST_FLAGS=--opt-level=3 -L lib\n")
        f.write("\n")
        f.write("all: lib bin test %s\n" % all)
        f.write("\n")
        f.write("lib:\n\tmkdir lib\n")
        f.write("\n")
        f.write("bin:\n\tmkdir bin\n")
        f.write("\n")
        f.write("test:\n\tmkdir test\n")
        f.write("\n")
        f.write("check: test test/.check\n")
        f.write("\n")
        f.write("test/.check: lib test %s\n" % " ".join("test/.%s.check" % m.name for m in modules.values() if m.has_tests()))
        f.write("\n")
        f.write("clean:\n\trm -r lib bin test\n")
        f.write("\n")
        f.write(rules) 


modules = [Bin("oculus-info", ["oculus-vr"]),
           LibMakefile("libovr_wrapper.a", "src/oculus-vr/", "src/oculus-vr/libovr_wrapper.a", ["cgmath", "libOculusVR.a"]),
           LibCMake("libOculusVR.a", "modules/OculusSDK/LibOVR/", "modules/OculusSDK/LibOVR/libOculusVR.a"),
           Lib("cgmath")]

if platform.system() == "Linux":
    modules += [Lib("oculus-vr", ["libOculusVR.a", "libedid.a", "cgmath", "libovr_wrapper.a"]),
                LibCMake("libedid.a", "modules/OculusSDK/3rdParty/EDID/", "modules/OculusSDK/3rdParty/EDID/libedid.a")]

elif platform.system() == "Darwin":
    modules += [Lib("oculus-vr", ["libOculusVR.a", "cgmath", "libovr_wrapper.a"])]

write_makefile(modules)