/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @file listview_curses.hh
 */

#ifndef __listview_curses_hh
#define __listview_curses_hh

#include <sys/types.h>

#include <string>
#include <vector>
#include <algorithm>

#include "strong_int.hh"
#include "view_curses.hh"

/** Strongly-typed integer for visible lines. */
STRONG_INT_TYPE(int, vis_line);

class listview_curses;

/**
 * Data source for lines to be displayed by the listview_curses object.
 */
class list_data_source {
public:
    virtual ~list_data_source() { };

    /** @return The number of rows in the list. */
    virtual size_t listview_rows(const listview_curses &lv) = 0;

    /**
     * Get the string value for a row in the list.
     *
     * @param row The row number.
     * @param value_out The destination for the string value.
     */
    virtual void listview_value_for_row(const listview_curses &lv,
                                        vis_line_t row,
                                        attr_line_t &value_out) = 0;
};

struct listview_overlay {
    listview_overlay(int y, const attr_line_t &al) : lo_y(y), lo_line(al) { };

    int         get_absolute_y(int height)
    {
        if (this->lo_y >= 0) {
            return this->lo_y;
        }

        return height + this->lo_y;
    };

    int         lo_y;
    attr_line_t lo_line;
};

class list_overlay_source {
public:
    virtual ~list_overlay_source() { };

    virtual size_t list_overlay_count(const listview_curses &lv) = 0;

    virtual bool list_value_for_overlay(const listview_curses &lv,
                                        vis_line_t y,
                                        attr_line_t &value_out) = 0;
};

/**
 * View that displays a list of lines that can optionally contain highlighting.
 */
class listview_curses
    : public view_curses {
public:
    typedef view_action<listview_curses> action;

    /** Construct an empty list view. */
    listview_curses();

    virtual ~listview_curses();

    /** @param src The data source delegate. */
    void set_data_source(list_data_source *src)
    {
        this->lv_source = src;
        this->reload_data();
    };

    /** @return The data source delegate. */
    list_data_source *get_data_source() const { return this->lv_source; };

    /** @param src The data source delegate. */
    void set_overlay_source(list_overlay_source *src)
    {
        this->lv_overlay_source = src;
        this->reload_data();
    };

    /** @return The overlay source delegate. */
    list_overlay_source *get_overlay_source()
    {
        return this->lv_overlay_source;
    };

    /**
     * @param va The action to invoke when the view is scrolled.
     * @todo Allow multiple observers.
     */
    void set_scroll_action(action va) { this->lv_scroll = va; };

    template<class _Receiver>
    void set_scroll_action(action::mem_functor_t<_Receiver> *mf)
    {
        this->lv_scroll = action(mf);
    };

    void set_show_scrollbar(bool ss) { this->lv_show_scrollbar = ss; };
    bool get_show_scrollbar() const { return this->lv_show_scrollbar; };

    /** @param win The curses window this view is attached to. */
    void set_window(WINDOW *win) { this->lv_window = win; };

    /** @return The curses window this view is attached to. */
    WINDOW *get_window() const { return this->lv_window; };

    void set_y(unsigned int y)
    {
        if (y != this->lv_y) {
            this->lv_y            = y;
            this->lv_needs_update = true;
        }
    };
    unsigned int get_y() const { return this->lv_y; };

    /**
     * Set the line number to be displayed at the top of the view.  If the
     * value is invalid, flash() will be called.  If the value is valid, the
     * new value will be set and the scroll action called.
     *
     * @param top The new value for top.
     * @param suppress_flash Don't call flash() if the top is out-of-bounds.
     */
    void set_top(vis_line_t top, bool suppress_flash = false)
    {
        if (top < 0 || (top > 0 && top >= this->get_inner_height())) {
            if (suppress_flash == false) {
                flash();
            }
        }
        else if (this->lv_top != top) {
            this->lv_top = top;
            this->lv_scroll.invoke(this);
            this->lv_needs_update = true;
        }
    };

    /** @return The line number that is displayed at the top. */
    vis_line_t get_top() const { return this->lv_top; };

    /** @return The line number that is displayed at the bottom. */
    vis_line_t get_bottom()
    {
        vis_line_t    retval, height;
        unsigned long width;

        this->get_dimensions(height, width);
        retval = std::min(this->lv_top + height - vis_line_t(1),
                          vis_line_t(this->get_inner_height() - 1));

        return retval;
    };

    /** @return True if the given line is visible. */
    bool is_visible(vis_line_t line)
    {
        return this->get_top() <= line && line <= this->get_bottom();
    };

    /**
     * Shift the value of top by the given value.
     *
     * @param offset The amount to change top by.
     * @param suppress_flash Don't call flash() if the offset is out-of-bounds.
     * @return The final value of top.
     */
    vis_line_t shift_top(vis_line_t offset, bool suppress_flash = false)
    {
        if (offset < 0 && this->lv_top == 0) {
            if (suppress_flash == false) {
                flash();
            }
        }
        else {
            this->set_top(std::max(vis_line_t(
                                       0),
                                   this->lv_top + offset), suppress_flash);
        }

        return this->lv_top;
    };


    /**
     * Set the column number to be displayed at the left of the view.  If the
     * value is invalid, flash() will be called.  If the value is valid, the
     * new value will be set and the scroll action called.
     *
     * @param left The new value for left.
     */
    void set_left(unsigned int left)
    {
        if (this->lv_left != left) {
            this->lv_left = left;
            this->lv_scroll.invoke(this);
            this->lv_needs_update = true;
        }
    };

    /** @return The column number that is displayed at the left. */
    unsigned int get_left() const { return this->lv_left; };

    /**
     * Shift the value of left by the given value.
     *
     * @param offset The amount to change top by.
     * @return The final value of top.
     */
    unsigned int shift_left(int offset)
    {
        if (offset < 0 && this->lv_left < (unsigned int)-offset) {
            this->set_left(0);
        }
        else {
            this->set_left(this->lv_left + offset);
        }

        return this->lv_left;
    };

    /**
     * Set the height of the view.  A value greater than one is considered to
     * be an absolute size.  A value less than or equal to zero makes the
     * height relative to the size of the enclosing window.
     *
     * @height The new height.
     */
    void set_height(vis_line_t height)
    {
        if (this->lv_height != height) {
            this->lv_height       = height;
            this->lv_needs_update = true;
        }
    };

    /** @return The absolute or relative height of the window. */
    vis_line_t get_height() const { return this->lv_height; };

    /** @return The number of rows of data in this view's source data. */
    vis_line_t get_inner_height() const
    {
        return vis_line_t(this->lv_source == NULL ? 0 :
                          this->lv_source->listview_rows(*this));
    };

    void set_needs_update() { this->lv_needs_update = true; };

    /**
     * Get the actual dimensions of the view.
     *
     * @param height_out The actual height of the view in lines.
     * @param width_out The actual width of the view in columns.
     */
    void get_dimensions(vis_line_t &height_out, unsigned long &width_out)
    {
        unsigned long height;

        getmaxyx(this->lv_window, height, width_out);
        if (this->lv_height < 1) {
            height_out = vis_line_t(height) +
                         this->lv_height -
                         vis_line_t(this->lv_y);
        }
        else {
            height_out = this->lv_height;
        }
    };

    /** This method should be called when the data source has changed. */
    void reload_data(void);

    /**
     * @param ch The input to be handled.
     * @return True if the key was eaten by this view.
     */
    bool handle_key(int ch);

    /**
     * Query the data source and draw the visible lines on the display.
     */
    void do_update(void);

protected:
    list_data_source *   lv_source; /*< The data source delegate. */
    list_overlay_source *lv_overlay_source;
    action       lv_scroll;         /*< The scroll action. */
    WINDOW *     lv_window;         /*< The window that contains this view. */
    unsigned int lv_y;              /*< The y offset of this view. */
    vis_line_t   lv_top;            /*< The line at the top of the view. */
    unsigned int lv_left;           /*< The column at the left of the view. */
    vis_line_t   lv_height;         /*< The abs/rel height of the view. */
    bool         lv_needs_update;   /*< Flag to indicate if a display update
                                     *  is needed.
                                     */
    bool lv_show_scrollbar;         /*< Draw the scrollbar in the view. */
};
#endif