#!/usr/bin/python
# -*- coding: utf-8 -*-

import argparse
import errno
import os
import subprocess
import sys
import tempfile
import time

def get_gradle_command_and_project_mtime(dir):
    """Find top-project gradlew or fallback to using gradle on sub-project dir.
While iterating the paths, also check mtime on build.gradle files"""
    topdir = dir
    build_gradle = None
    gradlew = None
    mtime = -1
    while True:
        test = os.path.join(topdir, 'build.gradle')
        if os.path.exists(test):
            if not build_gradle:
                build_gradle = test

            try:
                m = os.path.getmtime(test)
                if m > mtime:
                    mtime = m
            except OSError:
                pass

        test = os.path.join(topdir, 'gradlew')
        if os.path.exists(test):
            gradlew = test
            break

        test = os.path.dirname(topdir)
        if test == topdir:
            break
        topdir = test

    if gradlew:
        cmd = [gradlew, '-p', topdir]
    elif build_gradle:
        topdir = os.path.dirname(build_gradle)
        cmd = ['gradle', '-p', topdir]
    else:
        topdir = ''
        cmd = ['gradle']
    return (cmd, mtime, topdir)

def filter_source_files(files):
    """Remove any item not looking like a Java source file."""
    return [f for f in files if f.endswith('.java')]

def cleanup_output(tmp, real):
    """Remove any file in tmp that is older than the one in real"""
    offset = len(tmp)
    if tmp[-1] != '/':
        offset = offset + 1
    for (dirpath, _, files) in os.walk(tmp):
        realpath = os.path.join(real, dirpath[offset:])
        for filename in files:
            try:
                mtime = os.path.getmtime(os.path.join(realpath, filename))
                tmp = os.path.join(dirpath, filename)
                if os.path.getmtime(tmp) <= mtime:
                    os.remove(tmp)
            except OSError:
                pass

def run_javac(encoding, source, target, bootcp, cp, files, output, args,
              sourcefile, outdir):
    """Execute javac with the given options."""
    command = ['javac']
    if encoding:
        command.extend(['-encoding', encoding])
    if source:
        command.extend(['-source', source])
    if target:
        command.extend(['-target', target])
    if bootcp:
        command.extend(['-bootclasspath', bootcp])
    if outdir:
        command.extend(['-d', outdir])
        tmp = [outdir]
        if output:
            tmp.append(output)
        if cp:
            tmp.extend(cp)
        if tmp:
            command.extend(['-cp', ':'.join(tmp)])

        if os.fork() == 0:
            cleanup_output(outdir, output)
            sys.exit(0)
    else:
        if cp:
            command.extend(['-cp', ':'.join(cp)])
        if output:
            command.extend(['-d', output])
    command.extend(args)
    command.append(sourcefile)
    if outdir:
        return subprocess.call(command)
    else:
        with tempfile.NamedTemporaryFile(mode='w') as f:
            command.append('@' + f.name)
            for source in filter_source_files(files):
                f.write(source)
                f.write('\n')
                f.flush()
            return subprocess.call(command)

def file_in_list(needle, files):
    """Find needle in files and if so, return the list without needle.
Otherwise return None."""
    if os.path.exists(needle):
        for i in range(0, len(files) - 1):
            if os.path.samefile(needle, files[i]):
                return files[0:i] + files[i + 1:]
    return None

def figure_out_java_compilation(sessiondir, sourcefile, tempfile, checkstyle,
                                force=False):
    """Get options for Java compilation from gradle project and run javac."""
    (cmd, mtime, projectdir) = get_gradle_command_and_project_mtime(
        os.path.dirname(sourcefile))
    output = None
    cached = False
    if sessiondir != None:
        outdir = os.path.join(sessiondir, 'java_output')
        try:
            os.mkdir(outdir)
        except OSError as exc:
            if exc.errno != errno.EEXIST or not os.path.isdir(outdir):
                outdir = None
            pass
        cachefile = os.path.join(sessiondir, 'gradle_output')
        try:
            if not force and os.path.getmtime(cachefile) >= mtime:
                with open(cachefile, 'r') as f:
                    output = f.read()
                    cached = True
        except (OSError, IOError):
            pass
    else:
        outdir = None

    if not output:
        cmd.extend(['-q', 'flycheckAndroidJava'])
        output = subprocess.check_output(cmd, universal_newlines=True)
        if sessiondir != None:
            try:
                with open(cachefile, 'w') as f:
                    f.write(output)
            except IOError:
                pass

    output = output.split('\n')
    data = None
    first = None
    ret = 0
    compiled = False
    for line in output:
        if line == '***':
            if data:
                if not first:
                    first = data
                files = file_in_list(sourcefile, data['files'])
                if files:
                    ret = run_javac(data['encoding'], data['source'],
                                    data['target'], data['bootcp'],
                                    data['cp'], files, data['output'],
                                    data['args'], tempfile, outdir)
                    compiled = True
                    break
            data = {}
        elif data != None:
            if line.startswith('args='):
                data['args'] = line[6:-1].split(', ')
            elif line.startswith('encoding='):
                data['encoding'] = line[9:]
            elif line.startswith('bootcp='):
                data['bootcp'] = line[7:]
            elif line.startswith('cp='):
                data['cp'] = line[3:].split(':')
            elif line.startswith('source='):
                data['source'] = line[7:]
            elif line.startswith('target='):
                data['target'] = line[7:]
            elif line.startswith('files='):
                data['files'] = line[6:].split(':')
            elif line.startswith('output='):
                data['output'] = line[7:]

    if not compiled and data:
        if not first:
            first = data
        files = file_in_list(sourcefile, data['files'])
        if files:
            ret = run_javac(data['encoding'], data['source'], data['target'],
                            data['bootcp'], data['cp'], files, data['output'],
                            data['args'], tempfile, outdir)
            compiled = True

    if not compiled:
        # Probably need to rerun gradle to find group for sourcefile
        if cached and os.path.exists(sourcefile):
            return figure_out_java_compilation(sessiondir, sourcefile,
                                               tempfile, checkstyle, force=True)
        # OK, perhaps file doesn't exist yet or not yet added to gradle,
        # whatever, assume the first group is good enough
        if first:
            ret = run_javac(first['encoding'], first['source'], first['target'],
                            first['bootcp'], first['cp'], first['files'],
                            first['output'], first['args'], tempfile, outdir)
            compiled = True

    if not ret and checkstyle:
        cmd = ['java', '-jar',
               os.path.abspath(os.path.join(projectdir, checkstyle['jar']))]

        if 'config' in checkstyle:
            cmd.extend(['-c', checkstyle['config']])

        if 'properties' in checkstyle:
            cmd.extend(['-p', checkstyle['properties']])

        cmd.append(tempfile)
        if checkstyle['path']:
            cwd = os.path.join(projectdir, checkstyle['path'])
        elif len(projectdir):
            cwd = projectdir
        else:
            cwd = None
        ret = subprocess.call(cmd, cwd=cwd)

    if not ret and not compiled:
        print("Source file not in project and project seems empty!")
        ret = -1

    return ret

def main(argv):
    parser = argparse.ArgumentParser()
    parser.add_argument('--checkstyle-jar')
    parser.add_argument('--checkstyle-path')
    parser.add_argument('--checkstyle-config')
    parser.add_argument('--checkstyle-properties')
    parser.add_argument('sessiondir', nargs='?')
    parser.add_argument('sourcefile')
    parser.add_argument('tempfile', nargs='?')
    args = parser.parse_args(argv[1:])

    sourcefile = args.sourcefile
    tempfile = args.tempfile or sourcefile

    checkstyle = None
    if args.checkstyle_jar:
        checkstyle = {'jar': args.checkstyle_jar,
                      'path': args.checkstyle_path,
                      'config': args.checkstyle_config,
                      'properties': args.checkstyle_properties}

    sourcefile = os.path.abspath(sourcefile)
    return figure_out_java_compilation(args.sessiondir, sourcefile, tempfile,
                                       checkstyle)

sys.exit(main(sys.argv))