#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (c) 2015 Microsoft Corporation. All rights reserved.
# Released under Apache 2.0 license as described in the file LICENSE.
#
# Authors: Soonho Kong, Leonardo de Moura
import os
import subprocess
import platform

g_lean_exec_name  = "lean"
if platform.system() == "Windows" or platform.system().startswith("MSYS"):
    g_lean_exec_name  = "lean.exe"

if platform.system().startswith("MSYS"):
    # In MSYS platform, realpath has a strange behavior.
    #    os.path.realpath("c:\a\b\c") => \:\a\b\c
    g_leanutil_path   = os.path.abspath(os.path.normpath(__file__))
else:
    g_leanutil_path   = os.path.abspath(os.path.realpath(__file__))

g_lean_bin_dir = os.path.dirname(g_leanutil_path)

g_lean_path = os.path.join(g_lean_bin_dir, g_lean_exec_name)

if not os.path.isfile(g_lean_path):
    error("cannot find lean executable at " + os.path.abspath(g_lean_path))

class lean_exception(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)

def normalize_drive_name(name):
    if platform.system() == "Windows":
        drive, path = os.path.splitdrive(name)
        if drive == None:
            return name
        else:
            # Leo: return drive.lower() + path
            return path
    else:
        return name

def is_olean(fname):
    return fname.endswith(".olean")

def is_lean(fname):
    return fname.endswith(".lean")

def is_hlean(fname):
    return fname.endswith(".hlean")

LEAN_KIND=0
HLEAN_KIND=1
OLEAN_KIND=2

def get_lean_file_kind(fname):
    if is_lean(fname):
        return LEAN_KIND
    elif is_hlean(fname):
        return HLEAN_KIND
    elif is_olean(fname):
        return OLEAN_KIND
    else:
        raise lean_exception("unknown file kind: " + fname)

def olean_to_lean(fname, kind):
    if kind == LEAN_KIND:
        return fname[:-5] + "lean"
    elif kind == HLEAN_KIND:
        return fname[:-5] + "hlean"
    else:
        raise lean_exception("unsupported file kind: " + kind)

def lean_to_olean(fname):
    if is_lean(fname):
        return fname[:-4] + "olean"
    elif is_hlean(fname):
        return fname[:-5] + "olean"
    else:
        raise lean_exception("file '%s' is not a lean source file" % fname)

def get_timestamp(fname):
    try:
        return os.path.getmtime(fname)
    except OSError:
        return 0

def is_uptodate(fname):
    return get_timestamp(lean_to_olean(fname)) > get_timestamp(fname)

def lean_direct_deps(lean_file):
    deps = []
    proc = subprocess.Popen([g_lean_path, "--deps", lean_file],
                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    output = proc.communicate()[0].decode('utf-8').replace('\r\n', '\n')
    if not proc.returncode == 0:
        raise lean_exception(str(output))
    for olean_file in output.strip().splitlines():
        if olean_file:
            deps.append(normalize_drive_name(os.path.abspath(olean_file)))
    return deps

def lean_deps_core(lean_file, visited, deps, kind):
    if not lean_file in visited:
        visited[lean_file] = True
        deps.append(lean_file)
        for d in lean_direct_deps(lean_file):
            d = str(d)
            if is_olean(d):
                d = olean_to_lean(d, kind)
                lean_deps_core(d, visited, deps, kind)

def lean_deps(lean_file):
    visited = dict()
    deps    = []
    lean_deps_core(lean_file, visited, deps, get_lean_file_kind(lean_file))
    return deps

if __name__ == "__main__":
    for fname in lean_deps("/Users/leodemoura/projects/lean/library/data/nat/default.lean"):
        print("%s is ok: %s" % (fname, is_uptodate(fname)))