" File: pylint_fn.vim
" Author: Roman 'gryf' Dobosz (gryf73 at gmail.com)
" Version: 1.1
" Last Modified: 2015-09-20
"
" Description: " {{{
"
" Overview
" --------
" This plugin provides ":Pylint" command, which put pylint result into quickfix
" buffer. This function does not uses pylint[1] command line utility, only
" python pylint.lint module is used instead. So it makes the pylint
" egg/package required for running this script.
"
" This script uses python, therefore VIm should be compiled with python
" support. You can check it by issuing ":version" command, and search for
" "+python" inside features list.
"
" Couple of ideas was taken from pyflakes.vim[2] plugin.
"
" Installation
" ------------
" 1. Copy the pylint_fn.vim file to the $HOME/.vim/ftplugin/python or
"    $HOME/vimfiles/ftplugin/python or $VIM/vimfiles/ftplugin/python
"    directory. If python directory doesn't exists, it should be created.
"    Refer to the following Vim help topics for more information about Vim
"    plugins:
"       :help add-plugin
"       :help add-global-plugin
"       :help runtimepath
" 2. It should be possible to import pylint from python interpreter (it should
"    report no error):
"    >>> import pylint
"    >>>
"    If there are errors, install pylint first. Simplest way to do it, is to
"    use easy_install[3] shell command as a root:
"    # easy_install pylint
" 3. Restart Vim.
" 4. You can now use the ":Pylint" which will examine current python buffer
"    and open quickfix buffer with errors if any.
"
" [1] http://www.logilab.org/project/pylint
" [2] http://www.vim.org/scripts/script.php?script_id=2441
" [3] http://pypi.python.org/pypi/setuptools
" }}}

if exists("b:did_pylint_plugin")
    finish " only load once
else
    let b:did_pylint_plugin = 1
endif

if !exists('*s:CheckPylint')
    function s:CheckPylint()
        python << EOF
try:
    import vim
    from pylint import lint
    from pylint.reporters.text import TextReporter
except ImportError:
    vim.command("return 0")
vim.command("return 1")
EOF
    endfunction
endif

if s:CheckPylint() == 0
    finish
endif

if !exists("b:did_pylint_init")
    let b:did_pylint_init = 0

    if !has('python')
        echoerr "Error: pylint_fn.vim requires Vim to be compiled with +python"
        finish
    endif

    python << EOF
import sys
import re
from StringIO import StringIO

class VImPylint(object):

    sys_stderr = sys.stderr
    dummy_stderr = StringIO()
    conf_msg = 'No config file found, using default configuration\n'

    @classmethod
    def run(self):
        """execute pylint and fill the quickfix"""

        # clear QF window
        vim.command('call setqflist([])')

        # args
        args = ['-rn',  # display only the messages instead of full report
                vim.current.buffer.name]

        buf = StringIO()  # file-like buffer, instead of stdout
        reporter = TextReporter(buf)

        sys.stderr = self.dummy_stderr
        lint.Run(args, reporter=reporter, exit=False)
        sys.stderr = self.sys_stderr

        self.dummy_stderr.seek(0)
        error_list = self.dummy_stderr.readlines()
        self.dummy_stderr.truncate(0)
        if error_list and self.conf_msg in error_list:
            error_list.remove(self.conf_msg)
            if error_list:
                raise Exception(''.join(error_list))

        buf.seek(0)

        bufnr = vim.current.buffer.number
        code_line = {}
        error_list = []

        error_re = re.compile(r'^(?P<type>[C,R,W,E,F]):\s+?'
                              r'(?P<lnum>[0-9]+),\s+?'
                              r'(?P<col>[0-9]+):\s'
                              r'(?P<text>.*)$')
        for line in buf:
            line = line.rstrip()  # remove trailing newline character

            error_line = error_re.match(line)
            if error_line:
                error_line = error_line.groupdict()
                error_line["bufnr"] = bufnr

                error_list.append(error_line)

        vim.command('call setqflist(%s)' % str(error_list))
        if error_list:
            vim.command('copen')

EOF
    let b:did_pylint_init = 1
endif

if !exists('*s:Pylint')
    function s:Pylint()
        python << EOF
VImPylint.run()
EOF
    endfunction
endif

if !exists(":Pylint")
    command Pylint call s:Pylint()
endif