/** \file pager.h
  Pager support
*/

#include "complete.h"
#include "screen.h"
#include "reader.h"

#define PAGER_SELECTION_NONE ((size_t)(-1))

/* Represents rendering from the pager */
class page_rendering_t
{
public:
    int term_width;
    int term_height;
    size_t rows;
    size_t cols;
    size_t row_start;
    size_t row_end;
    size_t selected_completion_idx;
    screen_data_t screen_data;

    size_t remaining_to_disclose;

    bool search_field_shown;
    editable_line_t search_field_line;

    /* Returns a rendering with invalid data, useful to indicate "no rendering" */
    page_rendering_t();
};

/* The space between adjacent completions */
#define PAGER_SPACER_STRING L"  "
#define PAGER_SPACER_STRING_WIDTH 2

/* How many rows we will show in the "initial" pager */
#define PAGER_UNDISCLOSED_MAX_ROWS 4

typedef std::vector<completion_t> completion_list_t;
page_rendering_t render_completions(const completion_list_t &raw_completions, const wcstring &prefix);

class pager_t
{
    int available_term_width;
    int available_term_height;

    size_t selected_completion_idx;
    size_t suggested_row_start;

    /* Fully disclosed means that we show all completions */
    bool fully_disclosed;

    /* Whether we show the search field */
    bool search_field_shown;

    /* Returns the index of the completion that should draw selected, using the given number of columns */
    size_t visual_selected_completion_index(size_t rows, size_t cols) const;

    /** Data structure describing one or a group of related completions */
public:
    struct comp_t
    {
        /** The list of all completin strings this entry applies to */
        wcstring_list_t comp;

        /** The description */
        wcstring desc;

        /** The representative completion */
        completion_t representative;

        /** On-screen width of the completion string */
        int comp_width;

        /** On-screen width of the description information */
        int desc_width;

        /** Preferred total width */
        int pref_width;

        /** Minimum acceptable width */
        int min_width;

        comp_t() : comp(), desc(), representative(L""), comp_width(0), desc_width(0), pref_width(0), min_width(0)
        {
        }
    };

private:
    typedef std::vector<comp_t> comp_info_list_t;

    /* The filtered list of completion infos */
    comp_info_list_t completion_infos;

    /* The unfiltered list. Note there's a lot of duplication here. */
    comp_info_list_t unfiltered_completion_infos;

    wcstring prefix;

    bool completion_try_print(size_t cols, const wcstring &prefix, const comp_info_list_t &lst, page_rendering_t *rendering, size_t suggested_start_row) const;

    void recalc_min_widths(comp_info_list_t * lst) const;
    void measure_completion_infos(std::vector<comp_t> *infos, const wcstring &prefix) const;

    bool completion_info_passes_filter(const comp_t &info) const;

    void completion_print(size_t cols, int *width_per_column, size_t row_start, size_t row_stop, const wcstring &prefix, const comp_info_list_t &lst, page_rendering_t *rendering) const;
    line_t completion_print_item(const wcstring &prefix, const comp_t *c, size_t row, size_t column, int width, bool secondary, bool selected, page_rendering_t *rendering) const;


public:

    /* The text of the search field */
    editable_line_t search_field_line;

    /* Sets the set of completions */
    void set_completions(const completion_list_t &comp);

    /* Sets the prefix */
    void set_prefix(const wcstring &pref);

    /* Sets the terminal width and height */
    void set_term_size(int w, int h);

    /* Changes the selected completion in the given direction according to the layout of the given rendering. Returns true if the selection changed. */
    bool select_next_completion_in_direction(selection_direction_t direction, const page_rendering_t &rendering);

    /* Returns the currently selected completion for the given rendering */
    const completion_t *selected_completion(const page_rendering_t &rendering) const;

    /* Indicates the row and column for the given rendering. Returns -1 if no selection. */
    size_t get_selected_row(const page_rendering_t &rendering) const;
    size_t get_selected_column(const page_rendering_t &rendering) const;

    /* Produces a rendering of the completions, at the given term size */
    page_rendering_t render() const;

    /* Updates the rendering if it's stale */
    void update_rendering(page_rendering_t *rendering) const;

    /* Indicates if there are no completions, and therefore nothing to render */
    bool empty() const;

    /* Clears all completions and the prefix */
    void clear();

    /* Updates the completions list per the filter */
    void refilter_completions();

    /* Sets whether the search field is shown */
    void set_search_field_shown(bool flag);

    /* Gets whether the search field shown */
    bool is_search_field_shown() const;

    /* Indicates if we are navigating our contents */
    bool is_navigating_contents() const;

    /* Become fully disclosed */
    void set_fully_disclosed(bool flag);

    /* Position of the cursor */
    size_t cursor_position() const;

    /* Constructor */
    pager_t();
};