#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-
#
# Copyright (c) 2014 Microsoft Corporation. All rights reserved.
# Released under Apache 2.0 license as described in the file LICENSE.
#
# Author: Soonho Kong
#
import fnmatch
import os
import platform
import stat
import subprocess
import sys
import threading
import urllib
import glob
import argparse

g_lean_path    = "USE DEFAULT"
g_ltags_path   = "USE DEFAULT"
g_ninja_path   = "USE DEFAULT"
g_working_dir  = os.getcwd()
g_lean_files   = []
g_linja_path   = os.path.realpath(__file__)
g_lean_bin_dir = os.path.dirname(g_linja_path)
g_lean_options = []

def which(program):
    """ Lookup program in a path """
    import os
    def is_exe(fpath):
        return os.path.isfile(fpath) and os.access(fpath, os.X_OK)
    fpath, fname = os.path.split(program)
    if fpath:
        if is_exe(program):
            return program
    else:
        for path in os.environ["PATH"].split(os.pathsep):
            path = path.strip('"')
            exe_file = os.path.join(path, program)
            if is_exe(exe_file):
                return exe_file
    return None

def log(msg):
    print >> sys.stderr, msg

def log_nonewline(msg):
    print >> sys.stderr, ("\r%s" % msg),
    sys.stderr.flush()

def error(msg):
    log("Error: %s" % msg)
    exit(1)

def give_exec_permission(filename):
    "chmod +x filename"
    st = os.stat(filename)
    os.chmod(filename, st.st_mode | stat.S_IEXEC)

def show_download_progress(*data):
    file_size = int(data[2]/1000)
    total_packets = data[2]/data[1]
    downloaded_packets = data[0]
    log_nonewline("Download: size\t= %i kb, packet: %i/%i" % (file_size, downloaded_packets, total_packets+1))

def get_ninja_url():
    prefix = "https://leanprover.github.io/bin/"
    if platform.architecture()[0] == "64bit":
        if platform.system() == "Linux":
            return prefix + "ninja-1.5.1-linux-x86_64"
        elif platform.system() == "Windows" or platform.system().startswith("CYGWIN"):
            return prefix + "ninja-1.5.1-win.exe"
        elif platform.system() == "Darwin":
            return prefix + "ninja-1.5.1-osx"
    if platform.architecture()[0] == "32bit":
        if platform.system() == "Linux":
            return prefix + "ninja-1.5.1-linux-i386"
        elif platform.system() == "Windows" or platform.system().startswith("CYGWIN"):
            pass # TODO(soonhok): add support
        elif platform.system() == "Darwin":
            pass # TODO(soonhok): add support
    error("we do not have ninja executable for this platform: %s" % platform.platform())

def download_ninja_and_save_at(ninja_path):
    url = get_ninja_url()
    log("Downloading ninja: %s ===> %s\n" % (url, ninja_path))
    urllib.urlretrieve(url, ninja_path, show_download_progress)
    log("\n")
    if not os.path.isfile(ninja_path):
        error("failed to download ninja executable from %s" % url)
    give_exec_permission(ninja_path)
    return ninja_path

def check_required_packages():
    global g_lean_path, g_ltags_path, g_ninja_path
    lean_exec_name  = "lean.exe"  if platform.system() == "Windows" else "lean"
    ltags_exec_name = "ltags.exe" if platform.system() == "Windows" else "ltags"
    ninja_exec_name = "ninja.exe" if platform.system() == "Windows" else "ninja"

    if g_lean_path == "USE DEFAULT":
        g_lean_path = which(lean_exec_name) or os.path.join(g_lean_bin_dir, lean_exec_name)
    if g_ltags_path == "USE DEFAULT":
        g_ltags_path = which(ltags_exec_name) or os.path.join(g_lean_bin_dir, ltags_exec_name)
    if g_ninja_path == "USE DEFAULT":
        g_ninja_path = which(ninja_exec_name) or os.path.join(g_lean_bin_dir, ninja_exec_name)

    if not os.path.isfile(g_lean_path):
        error("cannot find lean executable at " + g_lean_path)
    if not os.path.isfile(g_ltags_path):
        error("cannot find ltags executable at " + g_ltags_path)
    if not os.path.isfile(g_ninja_path):
        g_ninja_path = download_ninja_and_save_at(g_ninja_path)

def make_deps(lean_file, dlean_file, olean_file):
    with open(dlean_file, "w") as f:
        deps = []
        proc = subprocess.Popen([g_lean_path, "--deps", lean_file], stdout=subprocess.PIPE, stderr=None)
        output = proc.communicate()[0]
        print >> f, olean_file + ": \\"
        for olean_file in output.strip().split("\n"):
            deps.append(olean_file)
        deps_str = " " + (" \\\n ".join(deps))
        print >> f, deps_str

def get_lean_names(lean_file):
    basename, ext = os.path.splitext(lean_file)
    item = {}
    item['base']  = basename;            item['lean']  = basename + ".lean";
    item['d']     = basename + ".d";     item['olean'] = basename + ".olean";
    item['clean'] = basename + ".clean"; item['ilean'] = basename + ".ilean"
    return item

def make_deps_all_files(directory, targets):
    lean_files = find_lean_files(directory, targets)
    threads = []
    i, num_of_files = 1, len(lean_files)
    for item in lean_files:
        lean_file  = item['lean']
        dlean_file = item['d']
        olean_file = item['olean']
        if not os.path.isfile(dlean_file) or os.path.getmtime(dlean_file) < os.path.getmtime(lean_file):
            thread = threading.Thread(target=make_deps, args = [lean_file, dlean_file, olean_file])
            sys.stderr.write("[%i/%i] generating dep... % -80s\r" % (i, num_of_files, dlean_file))
            sys.stderr.flush()
            thread.start()
            threads.append(thread)
        i += 1
    for thread in threads:
        thread.join()
    if threads != []:
        sys.stderr.write("\n")

def rule_clean():
    return """rule CLEAN
  command = "%s" -t clean
  description = Cleaning all built files...""" % g_ninja_path

def rule_lean():
    return """rule LEAN
  depfile = ${LEAN_BASE}.d
  command = "%s" %s "$in" -o "${LEAN_BASE}.olean" -c "${LEAN_BASE}.clean" -i "${LEAN_BASE}.ilean" """ \
      % (g_lean_path, " ".join(g_lean_options))

def rule_tags():
    return """rule LTAGS
  command = "%s" $in """ % (g_ltags_path)

def build_all(lean_files):
    str = "build all: phony"
    for item in lean_files:
        str = str + " " + item['olean']
    return str

def build_tags(lean_files):
    tags_file = os.path.join(g_working_dir, "TAGS")
    str = "build tags: phony " + tags_file + "\n"
    str += "build " + tags_file + ": LTAGS"
    for item in lean_files:
        str = str + " " + item['ilean']
    return str

def build_clean():
    return """build clean: CLEAN"""

def build_olean(lean, olean, clean, dlean, ilean, base):
    str = """build %s %s %s: LEAN %s | %s\n""" % (olean, ilean, clean, lean, dlean)
    str += "  LEAN_BASE=%s" % base
    return str

def ninja_default():
    return """default all"""

def make_build_ninja(directory, targets):
    with open(os.path.join(directory, "build.ninja"), "w") as f:
        lean_files = find_lean_files(directory, targets)
        print >> f, rule_clean()
        print >> f, rule_lean()
        print >> f, rule_tags()
        print >> f, build_all(lean_files)
        print >> f, build_tags(lean_files)
        print >> f, build_clean()
        for item in lean_files:
            print >> f, build_olean(item['lean'], item['olean'], item['clean'], item['d'], item['ilean'], item['base'])
        print >> f, ninja_default()

def do_deps(lean_executable, lean_files):
    for lean in lean_files:
        item = get_lean_names(lean)
        make_deps(lean_executable, item['lean'], item['d'], item['olean'])

def find_project_upward(path):
    project_file = os.path.join(path, ".project")
    if os.path.isfile(project_file):
        return path
    up = os.path.dirname(path)
    if up != path:
        return find_project_upward(up)
    return None

def handle_failure_for_flycheck(out, target):
    failed = set()
    for line in out.split("\n"):
        if line.startswith("FAILED:"):
            for lean_file in g_lean_files:
                lean = lean_file['lean']
                if lean in line and lean != target:
                    failed.add(lean)
    for failed_file in failed:
        print "FLYCHECK_BEGIN ERROR"
        print "%s:1:0: error: failed to compile %s" % (target, failed_file)
        print "FLYCHECK_END"
    if failed:
        call_lean(target)

def call_ninja(directory, args):
    targets = []
    for item in args.targets:
        if item.endswith(".lean"):
            targets.append(item[:-4] + "olean")
        else:
            targets.append(item)
    proc_out = proc_err = None
    if args.flycheck:
        proc_out = subprocess.PIPE
        proc_err = subprocess.PIPE

    proc = subprocess.Popen([g_ninja_path] + targets, stdout=proc_out, stderr=proc_err)
    proc.wait()

    if args.flycheck:
        out = proc.communicate()[0]
        print out
        if len(args.targets) == 1 and args.targets[0].endswith(".lean"):
            handle_failure_for_flycheck(out, args.targets[0])
    return proc.returncode

def call_lean(filename):
    proc = subprocess.Popen([g_lean_path] + g_lean_options + [filename],
                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    print proc.communicate()[0]
    return proc.returncode

def find_files(directory, pattern):
    if "/" in pattern:
        return glob.glob(os.path.join(directory, pattern))
    matches = []
    for root, dirnames, filenames in os.walk(directory):
        for filename in fnmatch.filter(filenames, pattern):
            matches.append(os.path.join(root, filename))
    return matches

def find_lean_files(project_dir, targets):
    if g_lean_files != []:
        return g_lean_files
    files = set()
    include_patterns, exclude_patterns = [], []
    with open(os.path.join(project_dir, ".project"), 'r') as f:
        for line in f:
            c = line[0]
            if c == '+':
                include_patterns.append(line[1:].strip())
            elif c == '-':
                exclude_patterns.append(line[1:].strip())
            elif c == '#':
                pass # Comment
            elif c == 'T':
                pass # TAG
            elif c == 'O':
                pass # Lean Option
    for pattern in include_patterns:
        files |= set(find_files(project_dir, pattern))
    for pattern in exclude_patterns:
        files -= set(find_files(project_dir, pattern))
    for file in targets:
        file = os.path.abspath(file)
        if file.endswith(".lean"):
            files.add(file)
        elif file.endswith(".olean"):
            file.add(file[:-5] + "lean")
    for f in files:
        g_lean_files.append(get_lean_names(f))
    return g_lean_files

def expand_target_to_fullname(target):
    if target in ["all", "clean", "tags", "clear-cache"]:
        return target
    elif os.path.isfile(target):
        return os.path.abspath(target)
    else:
        return os.path.join(g_working_dir, target)

def parse_arg(argv):
    global g_working_dir
    parser = argparse.ArgumentParser(description='linja: ninja build wrapper for Lean theorem prover.')
    parser.add_argument('--flycheck', '-F', action='store_true', default=False, help="Use --flycheck option for Lean.")
    parser.add_argument('--directory', '-C', action='store', help="change to DIR before doing anything else.")
    parser.add_argument('targets', nargs='*')
    args = parser.parse_args(argv)
    args.targets = map(expand_target_to_fullname, args.targets)
    if args.directory:
        os.chdir(args.directory)
        g_working_dir = args.directory
    return args

def get_lean_options(args):
    options = []
    if args.flycheck:
        options.append("--flycheck")
    return options

def clear_cache(project_dir):
    for item in find_lean_files(project_dir, []):
        if os.path.isfile(item['clean']):
            os.remove(item['clean'])

def main(argv=None):
    global g_lean_options
    if argv is None:
        argv = sys.argv[1:]
    check_required_packages()
    args = parse_arg(argv)
    project_dir = find_project_upward(g_working_dir)
    g_lean_options += get_lean_options(args)
    if not project_dir and args.targets in [[], ["all"], ["clean"], ["tags"], ["clear-cache"]]:
        error("cannot find project directory. Make sure that you have .project file at the project root.")
    if project_dir:
        os.chdir(project_dir)
        if args.targets == ["clear-cache"]:
            clear_cache(project_dir)
            return 0
        if not "clean" in args.targets:
            make_deps_all_files(project_dir, args.targets)
        make_build_ninja(project_dir, args.targets)
        return call_ninja(project_dir, args)
    else:
        returncode = 0
        for filename in args.targets:
            if os.path.isfile(filename) and filename.endswith(".lean"):
                returncode |= call_lean(filename)
        return returncode

if __name__ == "__main__":
    sys.exit(main())