/**
 * (C) Copyright 2007-2008 Jeremy Maitin-Shepard
 * (C) Copyright 2008 Nelson Elhage
 * (C) Copyright 2010 John J. Foerch
 *
 * Portions of this file (the JavaScript completer) were derived from Vimperator,
 * (C) Copyright 2006-2007 Martin Stubenschrott.
 *
 * Use, modification, and distribution are subject to the terms specified in the
 * COPYING file.
**/

in_module(null);

require("minibuffer.js");

/**
 * Generic completer function factory.
 *
 * Keyword arguments:
 * - $completions: Either a visit function or an array.  If a function, the
 *   function's argument is a function which pushes argument into the
 *   completions array.  Otherwise, it uses the provided array.
 * - $get_value: TODO.
 * - $get_string: TODO. Optional, default: identity function.
 * - $get_description: TODO: Optional, default: function returning "".
 * - $get_icon: optional. returns an icon for the completions line.
 *
 * TODO: Exactly what does this function return and how do you use it?
 */
define_keywords("$completions", "$get_string", "$get_description",
                "$get_value", "$get_icon");
function all_word_completer () {
    keywords(arguments,
             $get_description = function (x) "",
             $get_string = function (x) x,
             $get_icon = null);
    var completions = arguments.$completions;
    var get_string = arguments.$get_string;
    var get_description = arguments.$get_description;
    var get_value = arguments.$get_value;
    var get_icon = arguments.$get_icon;
    var arr;
    var completer = function (input, pos, conservative) {
        if (input.length == 0 && conservative)
            return undefined;
        var words = input.toLowerCase().split(" ");
        var data = arr.filter(function (x) {
                var s = get_string(x);
                var d = get_description(x);
                for (var i = 0; i < words.length; ++i) {
                    if (s.toLowerCase().indexOf(words[i]) == -1 &&
                        d.toLowerCase().indexOf(words[i]) == -1)
                    {
                        return false;
                    }
                }
                return true;
            });
        return {count: data.length,
                index_of:  function (x) data.indexOf(x),
                get_string: function (i) get_string(data[i]),
                get_description : function (i) get_description(data[i]),
                get_input_state: function (i) [get_string(data[i])],
                get_value: function (i) (get_value ? get_value(data[i]) : data[i]),
                get_icon: function (i) (get_icon ? get_icon(data[i]) : null)
               };
    };
    completer.refresh = function () {
        if (typeof completions == "function") {
            arr = [];
            completions(function (x) { arr.push(x); });
        } else
            arr = completions;
    };
    completer.refresh();
    return completer;
}

function get_common_prefix_length (a, b, len) {
    var lim;
    if (len != null && len < a.length)
        lim = len;
    else
        lim = a.length;
    if (b < lim)
        lim = b;
    var i;
    for (i = 0; i < lim && a[i] == b[i]; ++i);
    return i;
}

function get_partial_completion_input_state (x, prefix_end, suffix_begin, orig_str) {
    if (suffix_begin < orig_str.length) {
        if (orig_str[suffix_begin] == " ")
            suffix_begin++;
        let sel = x.length + prefix_end + 1;
        return [orig_str.substring(0, prefix_end) + x + " " + orig_str.substring(suffix_begin),
                sel, sel];
    } else {
        let sel = x.length + prefix_end;
        return [orig_str.substring(0, prefix_end) + x, sel, sel];
    }
}

function prefix_completer () {
    keywords(arguments,
             $get_description = function (x) "",
             $get_string = function (x) x,
             $get_icon = null);
    var completions = arguments.$completions;
    var get_string = arguments.$get_string;
    var get_description = arguments.$get_description;
    var get_value = arguments.$get_value;
    var get_icon = arguments.$get_icon;
    var arr;
    if (typeof completions == "function") {
        arr = [];
        completions(function (x) { arr.push(x); });
    } else
        arr = completions.slice();
    arr.sort(function (a,b) {
            a = get_string(a);
            b = get_string(b);
            if (a < b)
                return -1;
            if (a > b)
                return 1;
            return 0;
        });
    return function (input, pos, conservative) {
        var common_prefix = null;
        if (pos == 0 && conservative)
            return undefined;
        var input_prefix = input.substring(0,pos);
        var default_completion = null;
        var i = 0;
        var data = arr.filter(function (x) {
            var s = get_string(x);
            if (s == input) {
                default_completion = i;
                var retval = true;
            } else
                retval = (s.length >= pos && s.substring(0,pos) == input_prefix);
            if (retval)
                ++i;
            return retval;
        });
        if (data.length > 0) {
            let a = get_string(data[0]);
            let b = get_string(data[data.length - 1]);
            let i = get_common_prefix_length(a, b);
            if (i > pos) {
                common_prefix = a.substring(0,i);
                if (!default_completion) {
                    for (let j = 0; j < data.length; ++j) {
                        if (get_string(data[j]) == common_prefix) {
                            default_completion = j;
                            break;
                        }
                    }
                }
            }
        }
        return {count:data.length,
                index_of:  function (x) data.indexOf(x),
                get_string: function (i) get_string(data[i]),
                get_description: function (i) get_description(data[i]),
                get_input_state: function (i) get_partial_completion_input_state(get_string(data[i]), 0, pos, input),
                get_value: function (i) (get_value ? get_value(data[i]) : data[i]),
                get_icon: function (i) (get_icon ? get_icon(data[i]) : null),
                get common_prefix_input_state () {
                    return common_prefix && get_partial_completion_input_state(common_prefix, 0, pos, input);
                },
                default_completion: default_completion
               };
    };
}

function javascript_completer (buffer) {
    var window = buffer.window;

    return function (input, pos, conservative) {
        // Derived from Vimperator JavaScript completion
        if (pos == 0 && conservative)
            return undefined;
        var str = input.substr(0, pos);
        var matches = str.match(/^(.*?)(\s*\.\s*)?(\w*)$/);
        var filter = matches[3] || "";
        var start = matches[1].length - 1;
        var offset = matches[1] ? matches[1].length : 0;
        offset += matches[2] ? matches[2].length : 0;

        if (matches[2]) {
            let brackets = 0, parentheses = 0;
        outer:
            for (; start >= 0; start--) {
                switch (matches[1][start]) {
                case ";":
                case "{":
                    break outer;

                case "]":
                    brackets--;
                    break;
                case "[":
                    brackets++;
                    break;
                case ")":
                    parentheses--;
                    break;
                case "(":
                    parentheses++;
                    break;
                }
                if (brackets > 0 || parentheses > 0)
                    break outer;
            }
        }

        var objects = [];
        var source_obj ;
        var data = [];
        var common_prefix_len = null;
        var common_prefix = null;

        function add_completion (str, desc) {
            if (common_prefix != null)
                common_prefix_len = get_common_prefix_length(common_prefix, str, common_prefix_len);
            else
                common_prefix = str;
            data.push([str,desc]);
        }
        if (matches[1].substr(start+1)) {
            try {
                source_obj = eval(matches[1].substr(start+1));
            } catch (e) {}
        } else {
            source_obj = conkeror;
            if ("window".substring(0,filter.length) == filter)
                add_completion("window", "object");
            if ("buffer".substring(0,filter.length) == filter)
                add_completion("buffer", "object");
        }

        if (source_obj != null) {
            try {
                for (let i in source_obj) {
                    if (i.substring(0,filter.length) != filter)
                        continue;
                    let type, description;
                    try {
                        type = typeof(source_obj[i]);
                    } catch (e) { type = "unknown type"; }
                    if (type == "number" || type == "string" || type == "boolean") {
                        description = type + ": " + source_obj[i];
                    } else
                        description = type;
                    add_completion(i, description);
                }
            } catch (e) {}
        }
        if (common_prefix != null && common_prefix_len > 0)
            common_prefix = common_prefix.substr(0, common_prefix_len);
        else if (common_prefix_len != null)
            common_prefix = null;
        return {count:data.length,
                get_string: function (i) data[i][0],
                get_description: function (i) data[i][1],
                get_input_state: function (i) get_partial_completion_input_state(data[i][0], offset, pos, input),
                get common_prefix_input_state  () {
                    return common_prefix && get_partial_completion_input_state(common_prefix, offset, pos, input);
                }
               };
    }
}


function merge_completers (completers) {
    if(completers.length == 0)
        return null;
    return function (input, pos, conservative) {
        var results = [];
        var count = 0;
        for (let i = 0; i < completers.length; ++i) {
            let r = yield completers[i](input, pos, conservative);
            if (r != null && (r.count > 0 || "get_match_required" in r)) {
                results.push(r);
                count += r.count;
            }
        }
        function forward (name) {
            return function () {
                var args = Array.prototype.slice.call(arguments);
                var i = args.shift();
                for (var j=0; j < results.length; j++) {
                    var r = results[j];
                    if (i < r.count) {
                        if (name in r && r[name] != null) {
                            args.unshift(i);
                            return r[name].apply(this, args);
                        } else {
                            return null;
                        }
                    }
                    i -= r.count;
                }
                return null;
            }
        }
        function combine_or (name) {
            return function() {
                var b = false;
                for (var j=0; j < results.length; j++) {
                    var r = results[j];
                    if (name in r && r[name] != null) {
                        b = b || r[name].apply(this, arguments);
                    }
                }
                return b;
            }
        }
        yield co_return({count: count,
                         get_string: forward('get_string'),
                         get_description: forward('get_description'),
                         get_input_state: forward('get_input_state'),
                         get_icon: forward('get_icon'),
                         destroy: forward('destroy'),
                         get_match_required: combine_or('get_match_required')
                        });
    };
}

function nest_completions (completions, prefix, suffix) {
    if (prefix == null)
        prefix = "";
    if (suffix == null)
        suffix = "";
    function nest (x) {
        let [s, a, b] = x;
        if (a == null)
            a = s.length;
        if (b == null)
            b = s.length;
        return [prefix + s + suffix, a + prefix.length, b + prefix.length];
    }
    return {
        __proto__: completions,
        get_input_state: function (i) nest(completions.get_input_state(i)),
        get common_prefix_input_state () {
            let x = completions.common_prefix_input_state;
            if (x)
                return nest(x);
            return null;
        }
    };
}


/**
 * Generic simple completer for associative arrays.
 *
 * - `options' is an associative array, where the key represents a string that the
 *   user can complete to.
 * - `query' is the string to show in the minibuffer.
 */
function completer_with_mappings (options, query) {
    var completer = all_word_completer(
        $completions = function (push) {
            for (var i in options)
                push(i);
        });
    yield co_return(
        yield get_recent_conkeror_window().minibuffer.read(
            $prompt = query,
            $completer = completer
        )
    );
}

provide("minibuffer-completion");
