import os
from subprocess import Popen, PIPE, STDOUT

import dirutil
import regex
from buffer.emul import XTermBuffer
from method import Method, arg
from term import XTerm
from window import Window

class Exec(Method):
    '''Execute a command in a shell and put the output in a new buffer'''
    show_success = True
    args = [arg('cmd', dt='shell', p="Exec: ")]
    def _doit(self, w, path, cmd, cmdname=None, bufname=None, cmddir=None, opts={}):
        if cmddir: cmd = "cd %r && %s" % (cmddir, cmd)
        d = dict(opts)
        if path: d['path'] = path

        try:
            cmd = cmd % d
        except:
            pass

        if bufname is None: bufname = '*%s*' % self.name.title()
        if cmdname is None: cmdname = cmd.split(None, 1)[0]

        p       = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT)
        output  = p.stdout.read()
        result  = p.wait()
        status  = os.WEXITSTATUS(result)

        try:
            output2 = output.decode('utf-8')
        except:
            output2 = output.decode('latin-1')

        if not os.WIFEXITED(result) or status != 0:
            err = True
            msg = "failed to exec %r" % cmdname
        else:
            err = False
            msg = "exec(%r): ok" % (cmdname,)

        if output2:
            switch_to = err or self.show_success
            w.application.data_buffer(bufname, output2, switch_to=switch_to)
        w.set_error(msg)
        
    def _execute(self, w, **vargs):
        if w.buffer.btype == 'dir':
            name, path = dirutil.resolve_name_path(w)
            self._doit(w, path, vargs['cmd'])
            dirutil.find_name(w, name)
        elif hasattr(w.buffer, 'path'):
            path = w.buffer.path
            self._doit(w, path, vargs['cmd'])
        else:
            self._doit(w, None, vargs['cmd'])

class Man(Exec):
    '''Display a man page in a new buffer'''
    args = [arg('name', p="Program: ")]
    def _execute(self, w, **vargs):
        name   = vargs['name']
        cmd    = 'man %r' % name
        p      = Popen(cmd, shell=True, stdout=PIPE, stderr=PIPE)
        output = p.stdout.read()
        result = p.wait()
        status = os.WEXITSTATUS(result)
        if not os.WIFEXITED(result) or status != 0:
            err    = True
            errmsg = "found no page for %r" % name
        else:
            err    = False
            errmsg = "man(%r): ok" % name
        if output:
            xterm  = XTerm(cbuf=True)
            s      = xterm.term_filter(output)
            switch = err or self.show_success
            w.application.color_data_buffer('*Manpage*', s, switch_to=switch)
        w.set_error(errmsg)

class Pipe(Method):
    '''Pipe the buffer's contents through the command, and display the output in a new buffer'''
    args = [arg('cmd', dt="shell", p="Pipe: ")]
    def _parse(self, w, **vargs):
        # return 3 things: prog name, cmd, and whether to use the shell
        m = regex.shell_command.match(vargs['cmd'])
        if m:
            prog = m.group(0)
            return (prog, vargs['cmd'], True)
        else:
            return (None, None, False)

    def _display(self, w, data, status, prog, cmd, shell):
        lines = data.split('\n')
        if lines and lines[-1] == '':
            lines = lines[:-1]
        bufname = '*%s*' % self.name.title()
        b = w.application.data_buffer(bufname, data, switch_to=True, modename='error')
        b.orig_path = w.buffer.path
        w.set_error("%s exited with status %d" % (prog, status))

    def _execute(self, w, **vargs):
        (prog, cmd, shell) = self._parse(w, **vargs)
        if prog is None or not cmd:
            return
        
        self._dopipe(w, prog, cmd, shell)

    def _dopipe(self, w, prog, cmd, shell):
        pipe = Popen(cmd, shell=shell, stdin=PIPE, stdout=PIPE, stderr=STDOUT)
        pid = pipe.pid

        indata = w.buffer.make_string()
        pipe.stdin.write(indata)
        pipe.stdin.close()

        outdata = pipe.stdout.read()
        status  = pipe.wait() >> 8

        self._display(w, outdata, status, prog, cmd, shell)

class Grep(Pipe):
    '''Grep the buffer's contents for instances of a pattern, and display them in a new buffer'''
    args = [arg('pattern', dt="str", p="Pattern: ")]
    def _parse(self, w, **vargs):
        return ('grep', ('grep', '-E', '-n', vargs['pattern']), False)

class Sed(Pipe):
    '''Push the buffer's contents through a sed expression'''
    args = [arg('expression', dt="str", p="Expression: ")]
    def _parse(self, w, **vargs):
        return ('sed', ('sed', '-r', '-e', vargs['expression']), False)

class Interact(Method):
    '''Interact with a program via a PTY'''
    args = [arg('bname', dt="str", p="Buffer Name: ", dv=lambda w: '*Interact*'),
            arg('cmd', dt="shell", p="Command: ", dv=lambda w: 'bash')]
    modename = None
    reuse    = False
    def _execute(self, w, **vargs):
        bname = vargs['bname']
        cmd   = vargs['cmd']
        a = w.application
        if self.reuse and a.has_buffer_name(bname):
            a.switch_buffer(a.get_buffer_by_name(bname))
            return

        a.close_buffer_by_name(bname)
        b = XTermBuffer(a, 'bash', ['-c', cmd], name=bname,
                        modename=self.modename)
        a.add_buffer(b)
        Window(b, a)
        if a.window().buffer is not b:
            a.switch_buffer(b)