#!/usr/bin/env python
#
# 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:
# - DerivedNormalizationProps.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, collections

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)
    combines = {}
    canon_decomp = {}
    compat_decomp = {}
    general_category_mark = []

    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 xrange(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];

        # store decomposition, if given
        if decomp != "":
            if decomp.startswith('<'):
                seq = []
                for i in decomp.split()[1:]:
                    seq.append(int(i, 16))
                compat_decomp[code] = seq
            else:
                seq = []
                for i in decomp.split():
                    seq.append(int(i, 16))
                canon_decomp[code] = seq

        # record combining class, if any
        if combine != "0":
            if combine not in combines:
                combines[combine] = []
            combines[combine].append(code)

        if 'M' in [gencat] + expanded_categories.get(gencat, []):
            general_category_mark.append(code)
    general_category_mark = group_cat(general_category_mark)

    combines = to_combines(group_cats(combines))

    return (canon_decomp, compat_decomp, combines, general_category_mark)

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 ungroup_cat(cat):
    cat_out = []
    for (lo, hi) in cat:
        while lo <= hi:
            cat_out.append(lo)
            lo += 1
    return cat_out

def to_combines(combs):
    combs_out = []
    for comb in combs:
        for (lo, hi) in combs[comb]:
            combs_out.append((lo, hi, comb))
    combs_out.sort(key=lambda comb: comb[0])
    return combs_out

def format_table_content(f, content, indent):
    indent = " "*indent
    for c in content:
        f.write("%s%s,\n" % (indent, c))

def load_properties(f, interestingprops):
    fetch(f)
    props = {}
    re1 = re.compile("^ *([0-9A-F]+) *; *(\w+)")
    re2 = re.compile("^ *([0-9A-F]+)\.\.([0-9A-F]+) *; *(\w+)")

    for line in fileinput.input(os.path.basename(f)):
        prop = None
        d_lo = 0
        d_hi = 0
        m = re1.match(line)
        if m:
            d_lo = m.group(1)
            d_hi = m.group(1)
            prop = m.group(2)
        else:
            m = re2.match(line)
            if m:
                d_lo = m.group(1)
                d_hi = m.group(2)
                prop = m.group(3)
            else:
                continue
        if interestingprops and prop not in interestingprops:
            continue
        d_lo = int(d_lo, 16)
        d_hi = int(d_hi, 16)
        if prop not in props:
            props[prop] = []
        props[prop].append((d_lo, d_hi))

    # optimize if possible
    for prop in props:
        props[prop] = group_cat(ungroup_cat(props[prop]))

    return props

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]))):
    pub_string = ""
    if is_pub:
        pub_string = "pub "
    f.write("    %sconst %s: %s = &[\n" % (pub_string, name, t_type))
    format_table_content(f, [pfun(d) for d in t_data], 8)
    f.write("\n    ];\n\n")

def emit_strtab_table(f, name, keys, vfun, is_pub=True,
                      tab_entry_type='char', slice_element_sfun=escape_char):
    pub_string = ""
    if is_pub:
        pub_string = "pub "
    f.write("    %s const %s: &'static [(char, Slice)] = &[\n"
            % (pub_string, name))

    strtab = collections.OrderedDict()
    strtab_offset = 0

    # TODO: a more sophisticated algorithm here would not only check for the
    # existence of v in the strtab, but also v in contiguous substrings of
    # strtab, if that's possible.
    for k in keys:
        v = tuple(vfun(k))
        if v in strtab:
            item_slice = strtab[v]
        else:
            value_len = len(v)
            item_slice = (strtab_offset, value_len)
            strtab[v] = item_slice
            strtab_offset += value_len

        f.write("%s(%s, Slice { offset: %d, length: %d }),\n"
                % (" "*8, escape_char(k), item_slice[0], item_slice[1]))

    f.write("\n    ];\n\n")

    f.write("    %s const %s_STRTAB: &'static [%s] = &[\n"
            % (pub_string, name, tab_entry_type))

    for (v, _) in strtab.iteritems():
        f.write("%s%s,\n" % (" "*8, ', '.join(slice_element_sfun(c) for c in v)))

    f.write("\n    ];\n\n")

def emit_norm_module(f, canon, compat, combine, norm_props, general_category_mark):
    canon_keys = canon.keys()
    canon_keys.sort()

    compat_keys = compat.keys()
    compat_keys.sort()

    canon_comp = {}
    comp_exclusions = norm_props["Full_Composition_Exclusion"]
    for char in canon_keys:
        if True in map(lambda (lo, hi): lo <= char <= hi, comp_exclusions):
            continue
        decomp = canon[char]
        if len(decomp) == 2:
            if not canon_comp.has_key(decomp[0]):
                canon_comp[decomp[0]] = []
            canon_comp[decomp[0]].append( (decomp[1], char) )
    canon_comp_keys = canon_comp.keys()
    canon_comp_keys.sort()

    f.write("pub mod normalization {\n")
    f.write("""
pub struct Slice {
  pub offset: u16,
  pub length: u16,
}
""")

    def mkdata_fun(table):
        def f(char):
            return table[char]
        return f

    # TODO: should the strtab of these two tables be of type &'static str, for
    # smaller data?
    f.write("    // Canonical decompositions\n")
    emit_strtab_table(f, "canonical_table", canon_keys,
                      vfun=mkdata_fun(canon))

    f.write("    // Compatibility decompositions\n")
    emit_strtab_table(f, "compatibility_table", compat_keys,
                      vfun=mkdata_fun(compat))

    def comp_vfun(char):
        return sorted(canon_comp[char], lambda x, y: x[0] - y[0])

    f.write("    // Canonical compositions\n")
    # "&'static [(char, &'static [(char, char)])]", pfun=comp_pfun)
    emit_strtab_table(f, "composition_table", canon_comp_keys,
                      vfun=comp_vfun,
                      tab_entry_type="(char, char)",
                      slice_element_sfun=lambda pair: "(%s,%s)" % (escape_char(pair[0]),
                                                                   escape_char(pair[1])))

    f.write("""
    fn bsearch_range_value_table(c: char, r: &'static [(char, char, u8)]) -> u8 {
        use std::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 (_, _, result) = r[idx];
                result
            }
            Err(_) => 0
        }
    }\n
""")

    emit_table(f, "combining_class_table", combine, "&'static [(char, char, u8)]", is_pub=False,
            pfun=lambda x: "(%s,%s,%s)" % (escape_char(x[0]), escape_char(x[1]), x[2]))

    f.write("    pub fn canonical_combining_class(c: char) -> u8 {\n"
        + "        bsearch_range_value_table(c, combining_class_table)\n"
        + "    }\n")

    f.write("""
    fn bsearch_range_table(c: char, r: &'static [(char, char)]) -> bool {
        use std::cmp::Ordering::{Equal, Less, Greater};
        r.binary_search_by(|&(lo, hi)| {
             if lo <= c && c <= hi {
                 Equal
             } else if hi < c {
                 Less
             } else {
                 Greater
             }
         })
         .is_ok()
    }

    /// Return whether the given character is a combining mark (`General_Category=Mark`)
    pub fn is_combining_mark(c: char) -> bool {
        bsearch_range_table(c, general_category_mark)
    }

""")

    emit_table(f, "general_category_mark", general_category_mark, "&'static [(char, char)]", is_pub=False,
            pfun=lambda x: "(%s,%s)" % (escape_char(x[0]), escape_char(x[1])))

    f.write("""
}

""")

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-normalization is based on.
pub const UNICODE_VERSION: (u64, u64, u64) = (%s, %s, %s);

""" % unicode_version)
        (canon_decomp, compat_decomp, combines, general_category_mark) = \
            load_unicode_data("UnicodeData.txt")
        norm_props = load_properties("DerivedNormalizationProps.txt",
                     ["Full_Composition_Exclusion"])

        # normalizations and conversions module
        emit_norm_module(rf, canon_decomp, compat_decomp, combines, norm_props,
                         general_category_mark)