#!/usr/bin/env python3

# This is a naive implementation of the Python Hypertext preprocessor.
# For example, we just assume that we can hold the entire code in memory.
# Also, this is just the preprocessor, the resulting code will not be
# executed.

# Yes, the comments were here first and I wrote the code after writing them and then adjusted them to reality.

import sys

fd = open(sys.argv[1], "r")
lines = fd.read().split("\n")
fd.close()

# start text
output = "print(\"\"\""
# while not end of file
while len(lines)>0:
    # grab a line to process
    line = lines.pop(0)
    # iterate over line
    i=0
    while i < len(line):
        # attempt to grab the next few characters
        try:
            # variable(s) or code
            if line[i:i+3] in ["<?p", "<?="]:
                # end text
                output = output + "\"\"\""
                # variable(s)
                if line[i:i+3] == "<?=":
                    output = output + " + str("
                    # store variable list
                    # (may span more than just one line)
                    variable_list = ""
                    i = i+3
                    # walk until we either encounter a ?> or a line break
                    while True:
                        # if line break, attempt to go to next line
                        if len(line[i:])<2:
                            variable_list = variable_list + line[i:]
                            i = -1
                            try:
                                line = lines.pop(0)
                            except IndexError:
                                print("Unexpected end of file: No closing ?> found.", file=sys.stderr)
                                sys.exit(1)
                        else:
                            if line[i:i+2]=="?>":
                                i = i+1
                                break
                            else:
                                # add to variable list
                                variable_list = variable_list + line[i]
                        i = i+1
                    # split at comma and add the variables
                    output = output + ") + str(".join(variable_list.split(",")) + ") + "
                # code
                elif line[i:i+4] == "<?py":
                    output = output + ", end=\"\")\n"
                    # determine indent
                    #default to 0
                    indent = 0
                    try:
                        # any non whitespace characters left on line?
                        if not line[i+4:].strip()=="":
                            # attempt to use that as indent value
                            indent = int(line[i+4:])
                    # determining indent failed
                    except ValueError:
                        print("Invalid indent: \""+line[i+4:]+"\"\n" + line, file=sys.stderr)
                        sys.exit(1)
                    # attempt to check for end of code
                    try:
                        # grab code line
                        line = lines.pop(0)
                        # determine appropriate unindent length to get
                        # "raw" code
                        unindent_length = len(line)-len(line.lstrip())
                        while not "?>" in line:
                            # fix indent
                            line = indent*" "+line[unindent_length:]
                            # add code line
                            output = output + line + "\n"
                            # grab next code line
                            line = lines.pop(0)
                    # checking for end of code failed
                    except IndexError:
                        print("Unexpected end of file: No closing ?> found.", file=sys.stderr)
                        sys.exit(1)
                    # attempt to determine indent after end of code
                    indent = 0
                    try:
                        if not line[:line.find("?>")].strip()=="":
                            indent = int(line[:line.find("?>")])
                    except ValueError:
                        print("Invalid indent: \""+line[:line.find("?>")]+"\"\n" + line, file=sys.stderr)
                        sys.exit(1)
                    # add indent after end of code
                    output = output + " "*indent + "print("
                    # set i accordingly to add rest of line after code
                    # block end
                    i = line.find("?>")+2
                # assume accidental match
                else:
                    # start text
                    output = output + " + \""
                    # add text
                    output = output + line[i]
                    # end text
                    output = output + "\" + "
                # start text
                output = output + "\"\"\""
            else:
                # add text
                output = output + line[i]
        # handle last characters of line
        except IndexError:
            # add text
            output = output + line[i]
        i = i+1
    output = output + "\n"
# end text
output = output + "\"\"\", end=\"\")\n"

print(output)