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

define_variable("active_img_hint_background_color", "#88FF00", "Color for the active image hint background.");
define_variable("img_hint_background_color", "yellow", "Color for inactive image hint backgrounds.");
define_variable("active_hint_background_color", "#88FF00", "Color for the active hint background.");
define_variable("hint_background_color", "yellow", "Color for the inactive hint.");

/**
 * Register hints style sheet
 */
const hints_stylesheet = "chrome://conkeror/content/hints.css";
register_user_stylesheet(hints_stylesheet);

/**
 * buffer is a content_buffer
 *
 */
function hint_manager(window, xpath_expr, focused_frame, focused_element)
{
    this.window = window;
    this.hints = [];
    this.valid_hints = [];
    this.xpath_expr = xpath_expr;
    this.focused_frame = focused_frame;
    this.focused_element = focused_element;
    this.last_selected_hint = null;

    // Generate
    this.generate_hints();
}

hint_manager.prototype = {
    current_hint_string : "",
    current_hint_number : -1,

    /**
     * Create an initially hidden hint span element absolutely
     * positioned over each element that matches
     * hint_xpath_expression.  This is done recursively for all frames
     * and iframes.  Information about the resulting hints are also
     * stored in the hints array.
     */
    generate_hints : function () {
        var topwin = this.window;
        var top_height = topwin.innerHeight;
        var top_width = topwin.innerWidth;
        var hints = this.hints;
        var xpath_expr = this.xpath_expr;
        var focused_frame_hint = null, focused_element_hint = null;
        var focused_frame = this.focused_frame;
        var focused_element = this.focused_element;
        function helper(window, offsetX, offsetY) {
            var win_height = window.height;
            var win_width = window.width;

            // Bounds
            var minX = offsetX < 0 ? -offsetX : 0;
            var minY = offsetY < 0 ? -offsetY : 0;
            var maxX = offsetX + win_width > top_width ? top_width - offsetX : top_width;
            var maxY = offsetY + win_height > top_height ? top_height - offsetY : top_height;

            var scrollX = window.scrollX;
            var scrollY = window.scrollY;

            var doc = window.document;
            var res = doc.evaluate(xpath_expr, doc, xpath_lookup_namespace,
                                   Ci.nsIDOMXPathResult.UNORDERED_NODE_ITERATOR_TYPE,
                                   null /* existing results */);

            var base_node = doc.createElementNS(XHTML_NS, "span");
            base_node.className = "__conkeror_hint";

            var fragment = doc.createDocumentFragment();
            var rect, elem, text, node, show_text;
            while (true)
            {
                try {
                    elem = res.iterateNext();
                    if (!elem)
                        break;
                } catch (e) {
                    break; // Iterator may have been invalidated by page load activity
                }
                rect = elem.getBoundingClientRect();
                if (!rect || rect.left > maxX || rect.right < minX || rect.top > maxY || rect.bottom < minY)
                    continue;
                rect = elem.getClientRects()[0];
                if (!rect)
                    continue;
                show_text = false;
                if (elem instanceof Ci.nsIDOMHTMLInputElement || elem instanceof Ci.nsIDOMHTMLTextAreaElement)
                    text = elem.value;
                else if (elem instanceof Ci.nsIDOMHTMLSelectElement) {
                    if (elem.selectedIndex >= 0)
                        text = elem.item(elem.selectedIndex).text;
                    else
                        text = "";
                } else if (elem instanceof Ci.nsIDOMHTMLFrameElement) {
                    text = elem.name ? elem.name : "";
                } else if (/^\s*$/.test(elem.textContent) &&
                           elem.childNodes.length == 1 &&
                           elem.childNodes.item(0) instanceof Ci.nsIDOMHTMLImageElement) {
                    text = elem.childNodes.item(0).alt;
                    show_text = true;
                } else
                    text = elem.textContent;
                text = text.toLowerCase();

                node = base_node.cloneNode(true);
                node.style.left = (rect.left + scrollX) + "px";
                node.style.top = (rect.top + scrollY) + "px";
                fragment.appendChild(node);

                let hint = {text: text,
                            elem: elem,
                            hint: node,
                            img_hint: null,
                            visible: false,
                            show_text: show_text};
                if (elem.style) {
                    hint.saved_color = elem.style.color;
                    hint.saved_bgcolor = elem.style.backgroundColor;
                }
                hints.push(hint);

                if (elem == focused_element)
                    focused_element_hint = hint;
                else if ((elem instanceof Ci.nsIDOMHTMLFrameElement ||
                          elem instanceof Ci.nsIDOMHTMLIFrameElement) &&
                         elem.contentWindow == focused_frame)
                    focused_frame_hint = hint;
            }
            doc.documentElement.appendChild(fragment);

            /* Recurse into any IFRAME or FRAME elements */
            var frametag = "frame";
            while (true) {
                var frames = doc.getElementsByTagName(frametag);
                for (var i = 0; i < frames.length; ++i)
                {
                    elem = frames[i];
                    rect = elem.getBoundingClientRect();
                    if (!rect || rect.left > maxX || rect.right < minX || rect.top > maxY || rect.bottom < minY)
                        continue;
                    helper(elem.contentWindow, offsetX + rect.left, offsetY + rect.top);
                }
                if (frametag == "frame") frametag = "iframe"; else break;
            }
        }
        helper(topwin, 0, 0);
        this.last_selected_hint = focused_element_hint || focused_frame_hint;
    },

    /* Updates valid_hints and also re-numbers and re-displays all hints. */
    update_valid_hints : function () {
        this.valid_hints = [];
        var active_number = this.current_hint_number;

        var tokens = this.current_hint_string.split(" ");
        var rect, h, text, img_hint, doc, scrollX, scrollY;
        var hints = this.hints;

    outer:
        for (var i = 0; i < hints.length; ++i)
        {
            h = hints[i];
            text = h.text;
            for (var j = 0; j < tokens.length; ++j)
            {
                if (text.indexOf(tokens[j]) == -1)
                {
                    if (h.visible)
                    {
                        h.visible = false;
                        h.hint.style.display = "none";
                        if (h.img_hint)
                            h.img_hint.style.display = "none";
                        if (h.saved_color != null) {
                            h.elem.style.backgroundColor = h.saved_bgcolor;
                            h.elem.style.color = h.saved_color;
                        }
                    }
                    continue outer;
                }
            }

            var cur_number = this.valid_hints.length + 1;
            h.visible = true;

            if (h == this.last_selected_hint && active_number == -1)
                this.current_hint_number = active_number = cur_number;

            var img_elem = null;

            if (text.length == 0 && h.elem.firstChild &&
                h.elem.firstChild instanceof Ci.nsIDOMHTMLImageElement)
                img_elem = h.elem.firstChild;
            else if (h.elem instanceof Ci.nsIDOMHTMLImageElement)
                img_elem = h.elem;

            if (img_elem)
            {
                if (!h.img_hint)
                {
                    rect = img_elem.getBoundingClientRect();
                    if (rect) {
                        doc = h.elem.ownerDocument;
                        scrollX = doc.defaultView.scrollX;
                        scrollY = doc.defaultView.scrollY;
                        img_hint = doc.createElementNS(XHTML_NS, "span");
                        img_hint.className = "__conkeror_img_hint";
                        img_hint.style.left = (rect.left + scrollX) + "px";
                        img_hint.style.top = (rect.top + scrollY) + "px";
                        img_hint.style.width = (rect.right - rect.left) + "px";
                        img_hint.style.height = (rect.bottom - rect.top) + "px";
                        h.img_hint = img_hint;
                        doc.documentElement.appendChild(img_hint);
                    } else
                        img_elem = null;
                }
                if (img_elem) {
                    var bgcolor = (active_number == cur_number) ?
                        active_img_hint_background_color : img_hint_background_color;
                    h.img_hint.style.backgroundColor = bgcolor;
                    h.img_hint.style.display = "inline";
                }
            }

            if (!h.img_hint && h.elem.style)
                h.elem.style.backgroundColor = (active_number == cur_number) ?
                    active_hint_background_color : hint_background_color;

            if (h.elem.style)
                h.elem.style.color = "black";

            var label = "" + cur_number;
            if (h.elem instanceof Ci.nsIDOMHTMLFrameElement) {
                label +=  " " + text;
            } else if (h.show_text && !/^\s*$/.test(text)) {
                let substrs = [[0,4]];
                for (j = 0; j < tokens.length; ++j)
                {
                    let pos = text.indexOf(tokens[j]);
                    if(pos == -1) continue;
                    splice_range(substrs, pos, pos + tokens[j].length + 2);
                }
                label += " " + substrs.map(function(x) {
                    return text.substring(x[0],Math.min(x[1], text.length));
                }).join("..") + "..";
            }
            h.hint.textContent = label;
            h.hint.style.display = "inline";
            this.valid_hints.push(h);
        }

        if (active_number == -1)
            this.select_hint(1);
    },

    select_hint : function (index) {
        var old_index = this.current_hint_number;
        if (index == old_index)
            return;
        var vh = this.valid_hints;
        if (old_index >= 1 && old_index <= vh.length)
        {
            var h = vh[old_index - 1];
            if (h.img_hint)
                h.img_hint.style.backgroundColor = img_hint_background_color;
            if (h.elem.style)
                h.elem.style.backgroundColor = hint_background_color;
        }
        this.current_hint_number = index;
        if (index >= 1 && index <= vh.length)
        {
            var h = vh[index - 1];
            if (h.img_hint)
                h.img_hint.style.backgroundColor = active_img_hint_background_color;
            if (h.elem.style)
                h.elem.style.backgroundColor = active_hint_background_color;
            this.last_selected_hint = h;
        }
    },

    hide_hints : function () {
        for (var i = 0; i < this.hints.length; ++i)
        {
            var h = this.hints[i];
            if (h.visible) {
                h.visible = false;
                if (h.saved_color != null)
                {
                    h.elem.style.color = h.saved_color;
                    h.elem.style.backgroundColor = h.saved_bgcolor;
                }
                if (h.img_hint)
                    h.img_hint.style.display = "none";
                h.hint.style.display = "none";
            }
        }
    },

    remove : function () {
        for (var i = 0; i < this.hints.length; ++i)
        {
            var h = this.hints[i];
            if (h.visible && h.saved_color != null) {
                h.elem.style.color = h.saved_color;
                h.elem.style.backgroundColor = h.saved_bgcolor;
            }
            if (h.img_hint)
                h.img_hint.parentNode.removeChild(h.img_hint);
            h.hint.parentNode.removeChild(h.hint);
        }
        this.hints = [];
        this.valid_hints = [];
    }
};

/**
 * keyword arguments:
 *
 * $prompt
 * $callback
 * $abort_callback
 */
define_keywords("$keymap", "$auto", "$hint_xpath_expression", "$multiple");
function hints_minibuffer_state(continuation, buffer)
{
    keywords(arguments, $keymap = hint_keymap, $auto);
    basic_minibuffer_state.call(this, $prompt = arguments.$prompt);
    this.original_prompt = arguments.$prompt;
    this.continuation = continuation;
    this.keymap = arguments.$keymap;
    this.auto_exit = arguments.$auto ? true : false;
    this.xpath_expr = arguments.$hint_xpath_expression;
    this.auto_exit_timer_ID = null;
    this.multiple = arguments.$multiple;
    this.focused_element = buffer.focused_element;
    this.focused_frame = buffer.focused_frame;
}
hints_minibuffer_state.prototype = {
    __proto__: basic_minibuffer_state.prototype,
    manager : null,
    typed_string : "",
    typed_number : "",
    load : function (window) {
        if (!this.manager) {
            var buf = window.buffers.current;
            this.manager = new hint_manager(buf.top_frame, this.xpath_expr,
                                            this.focused_frame, this.focused_element);
        }
        this.manager.update_valid_hints();
    },
    unload : function (window) {
        if (this.auto_exit_timer_ID) {
            window.clearTimeout(this.auto_exit_timer_ID);
            this.auto_exit_timer_ID = null;
        }
        this.manager.hide_hints();
    },
    destroy : function () {
        if (this.auto_exit_timer_ID) {
            this.manager.window.clearTimeout(this.auto_exit_timer_ID);
            this.auto_exit_timer_ID = null;
        }
        this.manager.remove();
    },
    update_minibuffer : function (m) {
        if (this.typed_number.length > 0)
            m.prompt = this.original_prompt + " #" + this.typed_number;
        else
            m.prompt = this.original_prompt;
    },

    handle_auto_exit : function (m, delay) {
        let window = m.window;
        var num = this.manager.current_hint_number;
        if (this.auto_exit_timer_ID)
            window.clearTimeout(this.auto_exit_timer_ID);
        let s = this;
        this.auto_exit_timer_ID = window.setTimeout(function() { hints_exit(window, s); },
                                                    delay);
    },

    handle_input : function (m) {
        m._set_selection();

        this.typed_number = "";
        this.typed_string = m._input_text;
        this.manager.current_hint_string = this.typed_string;
        this.manager.current_hint_number = -1;
        this.manager.update_valid_hints();
        if (this.auto_exit) {
            if (this.manager.valid_hints.length == 1)
                this.handle_auto_exit(m, hints_auto_exit_delay);
            else if (this.manager.valid_hints.length > 1
                     && hints_ambiguous_auto_exit_delay > 0)
                this.handle_auto_exit(m, hints_ambiguous_auto_exit_delay);
        }
        this.update_minibuffer(m);
    }
};

define_variable("hints_auto_exit_delay", 500, "Delay (in milliseconds) after the most recent key stroke before a sole matching element is automatically selected.  If this is set to 0, automatic selection is disabled.");

define_variable("hints_ambiguous_auto_exit_delay", 0, "Delay (in milliseconds) after the most recent key stroke before the first of an ambiguous match is automatically selected.  If this is set to 0, automatic selection in ambiguous matches is disabled.");

interactive("hints-handle-number", function (I) {
    let s = I.minibuffer.check_state(hints_minibuffer_state);
    var ch = String.fromCharCode(I.event.charCode);
    var auto_exit = false;
    /* TODO: implement number escaping */
    // Number entered
    s.typed_number += ch;

    s.manager.select_hint(parseInt(s.typed_number));
    var num = s.manager.current_hint_number;
    if (s.auto_exit) {
        if (num > 0 && num <= s.manager.valid_hints.length) {
            if (num * 10 > s.manager.valid_hints.length)
                auto_exit = hints_auto_exit_delay;
            else if (hints_ambiguous_auto_exit_delay > 0)
                auto_exit = hints_ambiguous_auto_exit_delay;
        }
        if (num == 0) {
            if (!s.multiple) {
                hints_exit(I.window, s);
                return;
            }
            auto_exit = hints_auto_exit_delay;
        }
    }
    if (auto_exit)
        s.handle_auto_exit(I.minibuffer, auto_exit);
    s.update_minibuffer(I.minibuffer);
});

function hints_backspace(window, s) {
    let m = window.minibuffer;
    if (s.auto_exit_timer_ID) {
        window.clearTimeout(s.auto_exit_timer_ID);
        s.auto_exit_timer_ID = null;
    }
    if (s.typed_number.length > 0) {
        s.typed_number = s.typed_number.substring(0, s.typed_number.length - 1);
        var num = s.typed_number.length > 0 ? parseInt(s.typed_number) : 1;
        s.manager.select_hint(num);
    } else if (s.typed_string.length > 0) {
        s.typed_string = s.typed_string.substring(0, s.typed_string.length - 1);
        m._input_text = s.typed_string;
        m._set_selection();
        s.manager.current_hint_string = s.typed_string;
        s.manager.current_hint_number = -1;
        s.manager.update_valid_hints();
    }
    s.update_minibuffer(m);
}
interactive("hints-backspace", function (I) {
    hints_backspace(I.window, I.minibuffer.check_state(hints_minibuffer_state));
});

function hints_next(window, s, count) {
    if (s.auto_exit_timer_ID) {
        window.clearTimeout(s.auto_exit_timer_ID);
        s.auto_exit_timer_ID = null;
    }
    s.typed_number = "";
    var cur = s.manager.current_hint_number - 1;
    var vh = s.manager.valid_hints;
    if (vh.length > 0) {
        cur = (cur + count) % vh.length;
        if (cur < 0)
            cur += vh.length;
        s.manager.select_hint(cur + 1);
    }
    s.update_minibuffer(window);
}
interactive("hints-next", function (I) {
    hints_next(I.window, I.minibuffer.check_state(hints_minibuffer_state), I.p);
});

interactive("hints-previous", function (I) {
    hints_next(I.window, I.minibuffer.check_state(hints_minibuffer_state), -I.p);
});

function hints_exit(window, s)
{
    if (s.auto_exit_timer_ID) {
        window.clearTimeout(s.auto_exit_timer_ID);
        s.auto_exit_timer_ID = null;
    }
    var cur = s.manager.current_hint_number;
    var elem = null;
    if (cur > 0 && cur <= s.manager.valid_hints.length)
        elem = s.manager.valid_hints[cur - 1].elem;
    else if (cur == 0)
        elem = window.buffers.current.top_frame;
    if (elem) {
        var c = s.continuation;
        delete s.continuation;
        window.minibuffer.pop_state();
        if (c)
            c(elem);
    }
}

interactive("hints-exit", function (I) {
    hints_exit(I.window, I.minibuffer.check_state(hints_minibuffer_state));
});


/* FIXME: figure out why this needs to have a bunch of duplication */
define_variable(
    "hints_xpath_expressions",
    {
        images: {def: "//img | //xhtml:img"},
        frames: {def: "//iframe | //frame | //xhtml:iframe | //xhtml:frame"},
        links: {def:
                "//*[@onclick or @onmouseover or @onmousedown or @onmouseup or @oncommand or @class='lk' or @class='s'] | " +
                "//input[not(@type='hidden')] | //a | //area | //iframe | //textarea | //button | //select | " +
                "//xhtml:*[@onclick or @onmouseover or @onmousedown or @onmouseup or @oncommand or @class='lk' or @class='s'] | " +
                "//xhtml:input[not(@type='hidden')] | //xhtml:a | //xhtml:area | //xhtml:iframe | //xhtml:textarea | " +
                "//xhtml:button | //xhtml:select"},
        mathml: {def: "//m:math"}
    },
    "XPath expressions for each object class.");

minibuffer_auto_complete_preferences["media"] = true;

define_keywords("$buffer");
minibuffer.prototype.read_hinted_element = function () {
    keywords(arguments);
    var buf = arguments.$buffer;
    var s = new hints_minibuffer_state((yield CONTINUATION), buf, forward_keywords(arguments));
    this.push_state(s);
    var result = yield SUSPEND;
    yield co_return(result);
};