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

# file legacy_lyxpreview2ppm.py
# This file is part of LyX, the document processor.
# Licence details can be found in the file COPYING.

# author Angus Leeming
# Full author contact details are available in file CREDITS

# with much advice from members of the preview-latex project:
#   David Kastrup, dak@gnu.org and
#   Jan-Åke Larsson, jalar@mai.liu.se.
# and with much help testing the code under Windows from
#   Paul A. Rubin, rubin@msu.edu.

# This script takes a LaTeX file and generates a collection of
# ppm image files, one per previewed snippet.
# Example usage:
# legacy_lyxpreview2bitmap.py 0lyxpreview.tex 128 ppm 000000 faf0e6

# This script takes five arguments:
# TEXFILE:       the name of the .tex file to be converted.
# SCALEFACTOR:   a scale factor, used to ascertain the resolution of the
#                generated image which is then passed to gs.
# OUTPUTFORMAT:  the format of the output bitmap image files.
#                This particular script can produce only "ppm" format output.
# FG_COLOR:      the foreground color as a hexadecimal string, eg '000000'.
# BG_COLOR:      the background color as a hexadecimal string, eg 'faf0e6'.

# Decomposing TEXFILE's name as DIR/BASE.tex, this script will,
# if executed successfully, leave in DIR:
# * a (possibly large) number of image files with names
#   like BASE[0-9]+.ppm
# * a file BASE.metrics, containing info needed by LyX to position
#   the images correctly on the screen.

# The script uses several external programs and files:
# * A latex executable;
# * preview.sty;
# * dvips;
# * gs;
# * pnmcrop (optional).

# preview.sty is part of the preview-latex project
#   http://preview-latex.sourceforge.net/
# Alternatively, it can be obtained from
#   CTAN/support/preview-latex/

# The script uses the deprecated dvi->ps->ppm conversion route.
# If possible, please grab 'dvipng'; it's faster and more robust.
# If you have it then this script will not be invoked by
# lyxpreview2bitmap.py.
# Warning: this legacy support will be removed one day...

import glob, os, pipes, re, string, sys

from lyxpreview_tools import copyfileobj, error, find_exe, \
     find_exe_or_terminate, mkstemp, run_command

# Pre-compiled regular expression.
latex_file_re = re.compile("\.tex$")


def usage(prog_name):
    return "Usage: %s <latex file> <dpi> ppm <fg color> <bg color>\n"\
           "\twhere the colors are hexadecimal strings, eg 'faf0e6'"\
           % prog_name


def extract_metrics_info(log_file, metrics_file):
    metrics = open(metrics_file, 'w')

    log_re = re.compile("Preview: ([ST])")
    data_re = re.compile("(-?[0-9]+) (-?[0-9]+) (-?[0-9]+) (-?[0-9]+)")

    tp_ascent  = 0.0
    tp_descent = 0.0

    success = 0
    try:
        for line in open(log_file, 'r').readlines():
            match = log_re.match(line)
            if match == None:
                continue

            snippet = (match.group(1) == 'S')
            success = 1
            match = data_re.search(line)
            if match == None:
                error("Unexpected data in %s\n%s" % (log_file, line))

            if snippet:
                ascent  = string.atoi(match.group(2))
                descent = string.atoi(match.group(3))

                frac = 0.5
                if ascent >= 0 and descent >= 0:
                    ascent = float(ascent) + tp_ascent
                    descent = float(descent) - tp_descent

                    if abs(ascent + descent) > 0.1:
                        frac = ascent / (ascent + descent)

                    # Sanity check
                    if frac < 0 or frac > 1:
                            frac = 0.5

                metrics.write("Snippet %s %f\n" % (match.group(1), frac))

            else:
                tp_descent = string.atof(match.group(2))
                tp_ascent  = string.atof(match.group(4))

    except:
        # Unable to open the file, but do nothing here because
        # the calling function will act on the value of 'success'.
        warning('Warning in extract_metrics_info! Unable to open "%s"' % log_file)
        warning(`sys.exc_type` + ',' + `sys.exc_value`)

    return success


def extract_resolution(log_file, dpi):
    fontsize_re = re.compile("Preview: Fontsize")
    magnification_re = re.compile("Preview: Magnification")
    extract_decimal_re = re.compile("([0-9\.]+)")
    extract_integer_re = re.compile("([0-9]+)")

    found_fontsize = 0
    found_magnification = 0

    # Default values
    magnification = 1000.0
    fontsize = 10.0

    try:
        for line in open(log_file, 'r').readlines():
            if found_fontsize and found_magnification:
                break

            if not found_fontsize:
                match = fontsize_re.match(line)
                if match != None:
                    match = extract_decimal_re.search(line)
                    if match == None:
                        error("Unable to parse: %s" % line)
                    fontsize = string.atof(match.group(1))
                    found_fontsize = 1
                    continue

            if not found_magnification:
                match = magnification_re.match(line)
                if match != None:
                    match = extract_integer_re.search(line)
                    if match == None:
                        error("Unable to parse: %s" % line)
                    magnification = string.atof(match.group(1))
                    found_magnification = 1
                    continue

    except:
        warning('Warning in extract_resolution! Unable to open "%s"' % log_file)
        warning(`sys.exc_type` + ',' + `sys.exc_value`)

    # This is safe because both fontsize and magnification have
    # non-zero default values.
    return dpi * (10.0 / fontsize) * (1000.0 / magnification)


def legacy_latex_file(latex_file, fg_color, bg_color):
    use_preview_re = re.compile("(\\\\usepackage\[[^]]+)(\]{preview})")

    tmp = mkstemp()

    success = 0
    try:
        for line in open(latex_file, 'r').readlines():
            match = use_preview_re.match(line)
            if match == None:
                tmp.write(line)
                continue

            success = 1
            tmp.write("%s,dvips,tightpage%s\n\n" \
                      "\\AtBeginDocument{\\AtBeginDvi{%%\n" \
                      "\\special{!userdict begin/bop-hook{//bop-hook exec\n" \
                      "<%s%s>{255 div}forall setrgbcolor\n" \
                      "clippath fill setrgbcolor}bind def end}}}\n" \
                      % (match.group(1), match.group(2), fg_color, bg_color))

    except:
        # Unable to open the file, but do nothing here because
        # the calling function will act on the value of 'success'.
        warning('Warning in legacy_latex_file! Unable to open "%s"' % latex_file)
        warning(`sys.exc_type` + ',' + `sys.exc_value`)

    if success:
        copyfileobj(tmp, open(latex_file,"wb"), 1)

    return success


def crop_files(pnmcrop, basename):
    t = pipes.Template()
    t.append('%s -left' % pnmcrop, '--')
    t.append('%s -right' % pnmcrop, '--')

    for file in glob.glob("%s*.ppm" % basename):
        tmp = mkstemp()
        new = t.open(file, "r")
        copyfileobj(new, tmp)
        if not new.close():
            copyfileobj(tmp, open(file,"wb"), 1)


def legacy_conversion(argv):
    # Parse and manipulate the command line arguments.
    if len(argv) != 6:
        error(usage(argv[0]))

    dir, latex_file = os.path.split(argv[1])
    if len(dir) != 0:
        os.chdir(dir)

    dpi = string.atoi(argv[2])

    output_format = argv[3]
    if output_format != "ppm":
        error("This script will generate ppm format images only.")

    fg_color = argv[4]
    bg_color = argv[5]

    # External programs used by the script.
    path = string.split(os.environ["PATH"], os.pathsep)
    latex   = find_exe_or_terminate(["pplatex", "latex2e", "latex"], path)
    dvips   = find_exe_or_terminate(["dvips"], path)
    gs      = find_exe_or_terminate(["gswin32c", "gs"], path)
    pnmcrop = find_exe(["pnmcrop"], path)

    # Move color information into the latex file.
    if not legacy_latex_file(latex_file, fg_color, bg_color):
        error("Unable to move color info into the latex file")

    # Compile the latex file.
    latex_call = '%s "%s"' % (latex, latex_file)

    latex_status, latex_stdout = run_command(latex_call)
    if latex_status != None:
        error("%s failed to compile %s" \
              % (os.path.basename(latex), latex_file))

    # Run the dvi file through dvips.
    dvi_file = latex_file_re.sub(".dvi", latex_file)
    ps_file  = latex_file_re.sub(".ps",  latex_file)

    dvips_call = '%s -o "%s" "%s"' % (dvips, ps_file, dvi_file)

    dvips_status, dvips_stdout = run_command(dvips_call)
    if dvips_status != None:
        error("Failed: %s %s" % (os.path.basename(dvips), dvi_file))

    # Extract resolution data for gs from the log file.
    log_file = latex_file_re.sub(".log", latex_file)
    resolution = extract_resolution(log_file, dpi)

    # Older versions of gs have problems with a large degree of
    # anti-aliasing at high resolutions
    alpha = 4
    if resolution > 150:
        alpha = 2

    # Generate the bitmap images
    gs_call = '%s -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pnmraw ' \
              '-sOutputFile="%s%%d.ppm" ' \
              '-dGraphicsAlphaBit=%d -dTextAlphaBits=%d ' \
              '-r%f "%s"' \
              % (gs, latex_file_re.sub("", latex_file), \
                 alpha, alpha, resolution, ps_file)

    gs_status, gs_stdout = run_command(gs_call)
    if gs_status != None:
        error("Failed: %s %s" % (os.path.basename(gs), ps_file))

    # Crop the images
    if pnmcrop != None:
        crop_files(pnmcrop, latex_file_re.sub("", latex_file))

    # Extract metrics info from the log file.
    metrics_file = latex_file_re.sub(".metrics", latex_file)
    if not extract_metrics_info(log_file, metrics_file):
        error("Failed to extract metrics info from %s" % log_file)

    return 0


if __name__ == "__main__":
    legacy_conversion(sys.argv)
