#!/usr/bin/env python3
#
# Copyright 2011-2015 The Rust Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution and at
# http://rust-lang.org/COPYRIGHT.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.

# This script uses the following Unicode tables:
# - EastAsianWidth.txt
# - ReadMe.txt
# - UnicodeData.txt
#
# Since this should not require frequent updates, we just store this
# out-of-line and check the unicode.rs file into git.

import fileinput, re, os, sys, operator

preamble = '''// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// NOTE: The following code was generated by "scripts/unicode.py", do not edit directly

#![allow(missing_docs, non_upper_case_globals, non_snake_case)]
'''

# Mapping taken from Table 12 from:
# http://www.unicode.org/reports/tr44/#General_Category_Values
expanded_categories = {
    'Lu': ['LC', 'L'], 'Ll': ['LC', 'L'], 'Lt': ['LC', 'L'],
    'Lm': ['L'], 'Lo': ['L'],
    'Mn': ['M'], 'Mc': ['M'], 'Me': ['M'],
    'Nd': ['N'], 'Nl': ['N'], 'No': ['No'],
    'Pc': ['P'], 'Pd': ['P'], 'Ps': ['P'], 'Pe': ['P'],
    'Pi': ['P'], 'Pf': ['P'], 'Po': ['P'],
    'Sm': ['S'], 'Sc': ['S'], 'Sk': ['S'], 'So': ['S'],
    'Zs': ['Z'], 'Zl': ['Z'], 'Zp': ['Z'],
    'Cc': ['C'], 'Cf': ['C'], 'Cs': ['C'], 'Co': ['C'], 'Cn': ['C'],
}

# these are the surrogate codepoints, which are not valid rust characters
surrogate_codepoints = (0xd800, 0xdfff)

def fetch(f):
    if not os.path.exists(os.path.basename(f)):
        os.system("curl -O http://www.unicode.org/Public/UNIDATA/%s"
                  % f)

    if not os.path.exists(os.path.basename(f)):
        sys.stderr.write("cannot load %s" % f)
        exit(1)

def is_surrogate(n):
    return surrogate_codepoints[0] <= n <= surrogate_codepoints[1]

def load_unicode_data(f):
    fetch(f)
    gencats = {}

    udict = {}
    range_start = -1
    for line in fileinput.input(f):
        data = line.split(';')
        if len(data) != 15:
            continue
        cp = int(data[0], 16)
        if is_surrogate(cp):
            continue
        if range_start >= 0:
            for i in range(range_start, cp):
                udict[i] = data
            range_start = -1
        if data[1].endswith(", First>"):
            range_start = cp
            continue
        udict[cp] = data

    for code in udict:
        [code_org, name, gencat, combine, bidi,
         decomp, deci, digit, num, mirror,
         old, iso, upcase, lowcase, titlecase ] = udict[code]

        # place letter in categories as appropriate
        for cat in [gencat, "Assigned"] + expanded_categories.get(gencat, []):
            if cat not in gencats:
                gencats[cat] = []
            gencats[cat].append(code)

    gencats = group_cats(gencats)

    return gencats

def group_cats(cats):
    cats_out = {}
    for cat in cats:
        cats_out[cat] = group_cat(cats[cat])
    return cats_out

def group_cat(cat):
    cat_out = []
    letters = sorted(set(cat))
    cur_start = letters.pop(0)
    cur_end = cur_start
    for letter in letters:
        assert letter > cur_end, \
            "cur_end: %s, letter: %s" % (hex(cur_end), hex(letter))
        if letter == cur_end + 1:
            cur_end = letter
        else:
            cat_out.append((cur_start, cur_end))
            cur_start = cur_end = letter
    cat_out.append((cur_start, cur_end))
    return cat_out

def format_table_content(f, content, indent):
    line = " "*indent
    first = True
    for chunk in content.split(","):
        if len(line) + len(chunk) < 98:
            if first:
                line += chunk
            else:
                line += ", " + chunk
            first = False
        else:
            f.write(line + ",\n")
            line = " "*indent + chunk
    f.write(line)

# load all widths of want_widths, except those in except_cats
def load_east_asian_width(want_widths, except_cats):
    f = "EastAsianWidth.txt"
    fetch(f)
    widths = {}
    re1 = re.compile("^([0-9A-F]+);(\w+) +# (\w+)")
    re2 = re.compile("^([0-9A-F]+)\.\.([0-9A-F]+);(\w+) +# (\w+)")

    for line in fileinput.input(f):
        width = None
        d_lo = 0
        d_hi = 0
        cat = None
        m = re1.match(line)
        if m:
            d_lo = m.group(1)
            d_hi = m.group(1)
            width = m.group(2)
            cat = m.group(3)
        else:
            m = re2.match(line)
            if m:
                d_lo = m.group(1)
                d_hi = m.group(2)
                width = m.group(3)
                cat = m.group(4)
            else:
                continue
        if cat in except_cats or width not in want_widths:
            continue
        d_lo = int(d_lo, 16)
        d_hi = int(d_hi, 16)
        if width not in widths:
            widths[width] = []
        widths[width].append((d_lo, d_hi))
    return widths

def escape_char(c):
    return "'\\u{%x}'" % c

def emit_table(f, name, t_data, t_type = "&'static [(char, char)]", is_pub=True,
        pfun=lambda x: "(%s,%s)" % (escape_char(x[0]), escape_char(x[1])), is_const=True):
    pub_string = "const"
    if not is_const:
        pub_string = "let"
    if is_pub:
        pub_string = "pub " + pub_string
    f.write("    %s %s: %s = &[\n" % (pub_string, name, t_type))
    data = ""
    first = True
    for dat in t_data:
        if not first:
            data += ","
        first = False
        data += pfun(dat)
    format_table_content(f, data, 8)
    f.write("\n    ];\n\n")

def emit_charwidth_module(f, width_table):
    f.write("pub mod charwidth {")
    f.write("""
    use core::option::Option::{self, Some, None};
    use core::result::Result::{Ok, Err};

    #[inline]
    fn bsearch_range_value_table(c: char, is_cjk: bool, r: &'static [(char, char, u8, u8)]) -> u8 {
        use core::cmp::Ordering::{Equal, Less, Greater};
        match r.binary_search_by(|&(lo, hi, _, _)| {
            if lo <= c && c <= hi { Equal }
            else if hi < c { Less }
            else { Greater }
        }) {
            Ok(idx) => {
                let (_, _, r_ncjk, r_cjk) = r[idx];
                if is_cjk { r_cjk } else { r_ncjk }
            }
            Err(_) => 1
        }
    }
""")

    f.write("""
    #[inline]
    pub fn width(c: char, is_cjk: bool) -> Option<usize> {
        match c as usize {
            _c @ 0 => Some(0),          // null is zero width
            cu if cu < 0x20 => None,    // control sequences have no width
            cu if cu < 0x7F => Some(1), // ASCII
            cu if cu < 0xA0 => None,    // more control sequences
            _ => Some(bsearch_range_value_table(c, is_cjk, charwidth_table) as usize)
        }
    }

""")

    f.write("    // character width table. Based on Markus Kuhn's free wcwidth() implementation,\n")
    f.write("    //     http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c\n")
    emit_table(f, "charwidth_table", width_table, "&'static [(char, char, u8, u8)]", is_pub=False,
            pfun=lambda x: "(%s,%s,%s,%s)" % (escape_char(x[0]), escape_char(x[1]), x[2], x[3]))
    f.write("}\n\n")

def remove_from_wtable(wtable, val):
    wtable_out = []
    while wtable:
        if wtable[0][1] < val:
            wtable_out.append(wtable.pop(0))
        elif wtable[0][0] > val:
            break
        else:
            (wt_lo, wt_hi, width, width_cjk) = wtable.pop(0)
            if wt_lo == wt_hi == val:
                continue
            elif wt_lo == val:
                wtable_out.append((wt_lo+1, wt_hi, width, width_cjk))
            elif wt_hi == val:
                wtable_out.append((wt_lo, wt_hi-1, width, width_cjk))
            else:
                wtable_out.append((wt_lo, val-1, width, width_cjk))
                wtable_out.append((val+1, wt_hi, width, width_cjk))
    if wtable:
        wtable_out.extend(wtable)
    return wtable_out


def optimize_width_table(wtable):
    wtable_out = []
    w_this = wtable.pop(0)
    while wtable:
        if w_this[1] == wtable[0][0] - 1 and w_this[2:3] == wtable[0][2:3]:
            w_tmp = wtable.pop(0)
            w_this = (w_this[0], w_tmp[1], w_tmp[2], w_tmp[3])
        else:
            wtable_out.append(w_this)
            w_this = wtable.pop(0)
    wtable_out.append(w_this)
    return wtable_out

if __name__ == "__main__":
    r = "tables.rs"
    if os.path.exists(r):
        os.remove(r)
    with open(r, "w") as rf:
        # write the file's preamble
        rf.write(preamble)

        # download and parse all the data
        fetch("ReadMe.txt")
        with open("ReadMe.txt") as readme:
            pattern = "for Version (\d+)\.(\d+)\.(\d+) of the Unicode"
            unicode_version = re.search(pattern, readme.read()).groups()
        rf.write("""
/// The version of [Unicode](http://www.unicode.org/)
/// that this version of unicode-width is based on.
pub const UNICODE_VERSION: (u8, u8, u8) = (%s, %s, %s);

""" % unicode_version)
        gencats = load_unicode_data("UnicodeData.txt")

        ### character width module
        width_table = []
        for zwcat in ["Me", "Mn", "Cf"]:
            width_table.extend([(lo_hi[0], lo_hi[1], 0, 0) for lo_hi in gencats[zwcat]])
        width_table.append((4448, 4607, 0, 0))

        # get widths, except those that are explicitly marked zero-width above
        ea_widths = load_east_asian_width(["W", "F", "A"], ["Me", "Mn", "Cf"])
        # these are doublewidth
        for dwcat in ["W", "F"]:
            width_table.extend([(lo_hi1[0], lo_hi1[1], 2, 2) for lo_hi1 in ea_widths[dwcat]])
        width_table.extend([(lo_hi2[0], lo_hi2[1], 1, 2) for lo_hi2 in ea_widths["A"]])

        width_table.sort(key=lambda w: w[0])

        # soft hyphen is not zero width in preformatted text; it's used to indicate
        # a hyphen inserted to facilitate a linebreak.
        width_table = remove_from_wtable(width_table, 173)

        # optimize the width table by collapsing adjacent entities when possible
        width_table = optimize_width_table(width_table)
        emit_charwidth_module(rf, width_table)