# -*- coding: utf-8 -*-
""" History related magics and functionality """

# Stdlib imports
import fnmatch
import os

# IPython imports
from IPython.genutils import Term, ask_yes_no, warn
import IPython.ipapi

def magic_history(self, parameter_s = ''):
    """Print input history (_i<n> variables), with most recent last.
    
    %history       -> print at most 40 inputs (some may be multi-line)\\
    %history n     -> print at most n inputs\\
    %history n1 n2 -> print inputs between n1 and n2 (n2 not included)\\
    
    Each input's number <n> is shown, and is accessible as the
    automatically generated variable _i<n>.  Multi-line statements are
    printed starting at a new line for easy copy/paste.
    

    Options:

      -n: do NOT print line numbers. This is useful if you want to get a
      printout of many lines which can be directly pasted into a text
      editor.

      This feature is only available if numbered prompts are in use.

      -t: (default) print the 'translated' history, as IPython understands it.
      IPython filters your input and converts it all into valid Python source
      before executing it (things like magics or aliases are turned into
      function calls, for example). With this option, you'll see the native
      history instead of the user-entered version: '%cd /' will be seen as
      '_ip.magic("%cd /")' instead of '%cd /'.
      
      -r: print the 'raw' history, i.e. the actual commands you typed.
      
      -g: treat the arg as a pattern to grep for in (full) history.
      This includes the "shadow history" (almost all commands ever written).
      Use '%hist -g' to show full shadow history (may be very long).
      In shadow history, every index nuwber starts with 0.

      -f FILENAME: instead of printing the output to the screen, redirect it to
       the given file.  The file is always overwritten, though IPython asks for
       confirmation first if it already exists.
    """

    ip = self.api
    shell = self.shell
    if not shell.outputcache.do_full_cache:
        print 'This feature is only available if numbered prompts are in use.'
        return
    opts,args = self.parse_options(parameter_s,'gntsrf:',mode='list')

    # Check if output to specific file was requested.
    try:
        outfname = opts['f']
    except KeyError:
        outfile = Term.cout  # default
        # We don't want to close stdout at the end!
        close_at_end = False
    else:
        if os.path.exists(outfname):
            if not ask_yes_no("File %r exists. Overwrite?" % outfname): 
                print 'Aborting.'
                return

        outfile = open(outfname,'w')
        close_at_end = True

    if 't' in opts:
        input_hist = shell.input_hist
    elif 'r' in opts:
        input_hist = shell.input_hist_raw
    else:
        input_hist = shell.input_hist
            
    default_length = 40
    pattern = None
    if 'g' in opts:
        init = 1
        final = len(input_hist)
        parts = parameter_s.split(None,1)
        if len(parts) == 1:
            parts += '*'
        head, pattern = parts
        pattern = "*" + pattern + "*"
    elif len(args) == 0:
        final = len(input_hist)
        init = max(1,final-default_length)
    elif len(args) == 1:
        final = len(input_hist)
        init = max(1,final-int(args[0]))
    elif len(args) == 2:
        init,final = map(int,args)
    else:
        warn('%hist takes 0, 1 or 2 arguments separated by spaces.')
        print self.magic_hist.__doc__
        return
    width = len(str(final))
    line_sep = ['','\n']
    print_nums = not opts.has_key('n')
    
    found = False
    if pattern is not None:
        sh = ip.IP.shadowhist.all()
        for idx, s in sh:
            if fnmatch.fnmatch(s, pattern):
                print "0%d: %s" %(idx, s)
                found = True
    
    if found:
        print "==="
        print "shadow history ends, fetch by %rep <number> (must start with 0)"
        print "=== start of normal history ==="
        
    for in_num in range(init,final):        
        inline = input_hist[in_num]
        if pattern is not None and not fnmatch.fnmatch(inline, pattern):
            continue
            
        multiline = int(inline.count('\n') > 1)
        if print_nums:
            print >> outfile, \
                  '%s:%s' % (str(in_num).ljust(width),line_sep[multiline]),
        print >> outfile, inline,

    if close_at_end:
        outfile.close()


def magic_hist(self, parameter_s=''):
    """Alternate name for %history."""
    return self.magic_history(parameter_s)


def rep_f(self, arg):
    r""" Repeat a command, or get command to input line for editing

    - %rep (no arguments):
    
    Place a string version of last computation result (stored in the special '_'
    variable) to the next input prompt. Allows you to create elaborate command
    lines without using copy-paste::
    
        $ l = ["hei", "vaan"]       
        $ "".join(l)        
        ==> heivaan        
        $ %rep        
        $ heivaan_ <== cursor blinking    
    
    %rep 45
    
    Place history line 45 to next input prompt. Use %hist to find out the
    number.
    
    %rep 1-4 6-7 3
    
    Repeat the specified lines immediately. Input slice syntax is the same as
    in %macro and %save.
    
    %rep foo
    
    Place the most recent line that has the substring "foo" to next input.
    (e.g. 'svn ci -m foobar').    
    """
    
    opts,args = self.parse_options(arg,'',mode='list')
    ip = self.api    
    if not args:
        ip.set_next_input(str(ip.user_ns["_"]))
        return

    if len(args) == 1 and not '-' in args[0]:
        arg = args[0]
        if len(arg) > 1 and arg.startswith('0'):
            # get from shadow hist
            num = int(arg[1:])
            line = self.shadowhist.get(num)
            ip.set_next_input(str(line))
            return
        try:
            num = int(args[0])
            ip.set_next_input(str(ip.IP.input_hist_raw[num]).rstrip())
            return
        except ValueError:
            pass
        
        for h in reversed(self.shell.input_hist_raw):
            if 'rep' in h:
                continue
            if fnmatch.fnmatch(h,'*' + arg + '*'):
                ip.set_next_input(str(h).rstrip())
                return
        
    try:
        lines = self.extract_input_slices(args, True)
        print "lines",lines
        ip.runlines(lines)
    except ValueError:
        print "Not found in recent history:", args
        

_sentinel = object()

class ShadowHist:
    def __init__(self,db):
        # cmd => idx mapping
        self.curidx = 0
        self.db = db
        self.disabled = False
    
    def inc_idx(self):
        idx = self.db.get('shadowhist_idx', 1)
        self.db['shadowhist_idx'] = idx + 1
        return idx
        
    def add(self, ent):
        if self.disabled:
            return
        try:
            old = self.db.hget('shadowhist', ent, _sentinel)
            if old is not _sentinel:
                return
            newidx = self.inc_idx()
            #print "new",newidx # dbg
            self.db.hset('shadowhist',ent, newidx)
        except:
            IPython.ipapi.get().IP.showtraceback()
            print "WARNING: disabling shadow history"
            self.disabled = True
    
    def all(self):
        d = self.db.hdict('shadowhist')
        items = [(i,s) for (s,i) in d.items()]
        items.sort()
        return items

    def get(self, idx):
        all = self.all()
        
        for k, v in all:
            #print k,v
            if k == idx:
                return v


def init_ipython(ip):
    import ipy_completers

    ip.expose_magic("rep",rep_f)        
    ip.expose_magic("hist",magic_hist)            
    ip.expose_magic("history",magic_history)

    ipy_completers.quick_completer('%hist' ,'-g -t -r -n')
