/* Magic comment for runcprotoall: @generate_cproto@ */

#include "monolog.h"
#include "zori.h"
#include "zori_widget.h"
#include "zori_caption.h"
#include "zori_longtext.h"
#include "zori_page.h"
#include <math.h>


#define ZORI_LONGTEXT_LINE_POS_MAX 99999
#define ZORI_LONGTEXT_ANIMATION_CYCLE_TIME 4.0
#define ZORI_LONGTEXT_PAUSE_MARKER_DAMPER 2.0
#define ZORI_LONGTEXT_PAUSE_MARKER_SCALE 0.75
#define ZORI_LONGTEXT_DEFAULT_DELAY 0.2


struct zori_longtext * zori_widget_to_longtext(struct zori_widget * widget) {
  if (!zori_widget_is_type(widget, ZORI_WIDGET_TYPE_LONGTEXT)) return NULL;
  return ZORI_CONTAINER_OF(widget, struct zori_longtext, widget);
}



static bool 
zori_longtext_calculate_lines_aid(int line_num, const zori_string *line, void * extra) {
  struct zori_longtext * longtext = extra;
  longtext->state.total = line_num + 1;
  return true;
}

/** Calculates the amount of lines needed for the longtext as per al_do_multiline_text 
 * The value is set in longtext->state.total and returned;
 */

int zori_longtext_calculate_lines(struct zori_longtext * longtext) {
  double width = longtext->widget.inner.size.x;
  longtext->state.total = 0;
  al_do_multiline_ustr(zori_widget_font(&longtext->widget), width,
       longtext->text, zori_longtext_calculate_lines_aid, longtext);
  return longtext->state.total;
}

struct zori_longtext *
zori_longtext_set(struct zori_longtext * longtext, const zori_string * text) {
  if (longtext) {
    if (longtext->text) {
      ustr_free(longtext->text);
      longtext->text = NULL;
      longtext->state.total = 0;
    }
    if (text) { 
      longtext->text = ustr_dup(text);
      if (!longtext->text) {
        longtext->state.total = 0;
        LOG_ERROR("Out of memory in longtext setup.\n");
        return NULL;
      } else {
        zori_longtext_calculate_lines(longtext);
        LOG_DEBUG("Longtext lines: %d\n", longtext->state.total);
      }
    }
  }
  return longtext;
} 

struct zori_longtext *
zori_longtext_set_cstr(struct zori_longtext * longtext, const char * cstr) {
  const USTR * ustr; 
  USTR_INFO info;
  if (!cstr) cstr = "EMPTY!!!";
  ustr = ustr_refcstr(&info, cstr);
  return zori_longtext_set(longtext, ustr);
}

struct zori_longtext *
zori_longtext_init_cstr(struct zori_longtext * longtext, const char * cstr) {
  longtext->text = NULL;
  return zori_longtext_set_cstr(longtext, cstr);
}

void zori_longtext_done(struct zori_longtext * longtext) {
  zori_longtext_set(longtext, NULL);
}

/** Gets the number of lines in one page. Always returns at least 1. */
int zori_longtext_page_lines(struct zori_longtext * longtext) {    
  if (!longtext) return 1;
  if (longtext->settings.lines > 1) {
    return longtext->settings.lines;
  }
  return 1;  
}


/** Sets the number of lines in one page. Sets at least 1. */
int zori_longtext_page_lines_(struct zori_longtext * longtext, int pl) {    
  if (!longtext) return -1;
  if (pl < 1) {
    pl = 1;
  }
  longtext->settings.lines = pl;
  return longtext->settings.lines;
}


/** Gets the current text page for a longtext. Page 0 is the first page, etc.*/
int zori_longtext_page(struct zori_longtext * longtext) {
  int pl = 1;
  if (!longtext) return -2;
  return longtext->state.page;
}


/** Gets the last page number (inclusive) for a longtext or negative on error. */
int zori_longtext_last_page(struct zori_longtext * longtext) {
  int pl = 1;
  if (!longtext) return -2;
  pl = zori_longtext_page_lines(longtext);
  return longtext->state.total / pl;
}




/** Advances long text to the given page. Automatically unpauses as well. */
int zori_longtext_page_(struct zori_longtext * longtext, int page) {
  int pl = 1;
  int line = 1;
  if (!longtext) return -2;
  if (!longtext) return -2;
  if (page < 0) return -3;  
  pl    = zori_longtext_page_lines(longtext);  
  line  = page * pl;
  /* Check for page overflow. */
  LOG_NOTE("Selecting page nr %d, line nr %d, limit of %d", page, line, longtext->state.total);
  

  if (line >= longtext->state.total) {
    LOG_WARNING("Cannot select page nr %d, line nr %d, more than limit of %d", 
      page, line, longtext->state.total);
    return -5;
  }
   
  longtext->state.paused  = false;
  longtext->state.line    = line;
  longtext->state.page    = page;

  /* Negative delay is instant display. */
  if (longtext->settings.delay < 0) {  
    longtext->state.position = ZORI_LONGTEXT_LINE_POS_MAX;
  } else {
    longtext->state.position = 0;
  }  
  return page;  
}

/* Returns TRUE if the longtext node is at the end of the text to display,
 * false if not (more text to display) */
int zori_longtext_at_end(struct zori_longtext * longtext) {
  if (!longtext) return FALSE;
  return  ((longtext->state.line >= longtext->state.total)
   /* && (longtext->state.position >= ZORI_LONGTEXT_LINE_POS_MAX) */);
}



/* This function is the helper callback that implements
 * updating scrolled/partial text for Longtexts. 
 */
static bool 
zori_longtext_update_custom_partial_text(int line_num, const zori_text *line, void * extra) {
  struct zori_longtext * longtext = extra;
  int last_line   = line_num;
  int start_line  = longtext->state.page * longtext->settings.lines;
  int stop_line   = (longtext->state.page + 1) * longtext->settings.lines;
  int line_length  = al_ustr_length(line);
  
  /* Don't draw lines before start but keep on drawing (for later lines) */
  if (line_num < start_line) return true;
  /* Don't draw lines after stop, but keep calculating to get correct amount of lines */
  if (line_num >= stop_line) return true;
  /* Reveal letter by letter on last line */
  if (line_num == longtext->state.line) {
    /* Advance the position automatically if not paused. */
    if (!longtext->state.paused) {
      if (longtext->settings.flags & ZORI_LONGTEXT_SETTING_FLAG_SHOW_LETTERS) {
        al_ustr_next(line, &longtext->state.position);
      } else {
        int next_word = al_ustr_find_set_cstr(line, longtext->state.position + 1, " \t\r\n");
        if (next_word > 0) {
          longtext->state.position = next_word;
        } else if (longtext->state.position < (line_length -1)) { /* skip almost to the end of the line. */
          longtext->state.position = line_length;
        } else { /* Advance, to end of line. */
          al_ustr_next(line, &longtext->state.position);
        }
      }
    }
    /* Reached eol, advance to next line. */
    if (longtext->state.position >= line_length) {
      int pl = zori_longtext_page_lines(longtext);
      /* Is if the text window is full, pause, otherwise show the next line. */
      if (longtext->state.line >= (stop_line-1)) {
        longtext->state.paused = true;
      } else {
        longtext->state.line++;
        longtext->state.position = 0;
      }
    }
  }
  return true;
}


/* Rerurns whether or no t the end of a page is reached on a longtext */
int zori_longtext_end_of_page(struct zori_longtext * longtext) {
  int limit;
  if (zori_longtext_at_end(longtext)) return TRUE;
  limit = (longtext->state.page + 1) * longtext->settings.lines;
  return (longtext->state.line >= limit);
}

/* Updates the longtext, enables scrolling and per character display. */
void zori_longtext_update_longtext(struct zori_longtext * longtext, double dt) {
  float width = longtext->widget.inner.size.x;
  zori_text * text = longtext->text;
  
  if (!text) {
    LOG_WARNING("Attempted to update a NULL longtext.");
    return;
  }
  
  longtext->state.anitime += dt;
  if (longtext->state.anitime > ZORI_LONGTEXT_ANIMATION_CYCLE_TIME) {
     longtext->state.anitime = 0;
  }
  
  /* Delay advance of characters somewhat if requested. */
  if (longtext->settings.delay > 0.0) {
    longtext->state.wait += dt;
    if (longtext->state.wait < longtext->settings.delay) return;
    longtext->state.wait = 0;
  }
  
  al_do_multiline_ustr(zori_widget_font(&longtext->widget), width,
      text, zori_longtext_update_custom_partial_text, longtext);
  
  /* pause if the last line of the page is reached, and prevent overflow. */
  if (zori_longtext_end_of_page(longtext)) {
    longtext->state.paused    = TRUE;
    longtext->state.position  = ZORI_LONGTEXT_LINE_POS_MAX;
  }
  
}

/* Calculates the x and y position where to draw text, taking alignment and
 * margin into consideration. */
static BeVec
zori_longtext_calculate_text_position(struct zori_longtext * longtext) {
  BeVec result;
  int flags = longtext->widget.style.text.flags;
  result.x  = longtext->widget.inner.at.x;
  result.y  = longtext->widget.inner.at.y;

  if (flags & ALLEGRO_ALIGN_CENTER) {
    result.x += longtext->widget.inner.size.x / 2;
  } else if (flags & ALLEGRO_ALIGN_RIGHT) {
    result.x += longtext->widget.inner.size.x;
  }
  return result;
}

/* Draws the longtext, if it has a single line.. */
void zori_longtext_draw_text(struct zori_longtext * longtext) {
  zori_font * font;
  int flags;
  BeVec pos = zori_longtext_calculate_text_position(longtext);
  font      = zori_widget_font(&longtext->widget);
  flags     = longtext->widget.style.text.flags | ALLEGRO_ALIGN_INTEGER;
  zori_color shadow = longtext->widget.style.back.color;
  zori_color fore   = longtext->widget.style.text.color;
  
  /* Draw the text twice, once offset in bg color to produce a shadow, 
   and once normally with foreground color. */
  al_draw_ustr(font, shadow, pos.x + 1, pos.y + 1,
    flags, longtext->text);
  al_draw_ustr(font, fore, pos.x, pos.y,
    flags, longtext->text);
}


/**
 * Draws the paused marker if needed.
 */
static void zori_longtext_draw_paused_marker(const struct zori_longtext * longtext) {
  struct zori_root * root = zori_get_root();
  int line_skip;
  float x, y, x1, y1, x2, y2, x3, y3, sp, ms;
  
  if (!longtext->state.paused) return; 
    
  line_skip = (longtext->state.page + 1 * longtext->settings.lines);
  x   = longtext->widget.inner.at.x ; 
  y   = longtext->widget.inner.at.y ;
  sp  = longtext->settings.spacing;
  y  += line_skip * sp;
  ms  = sp * ZORI_LONGTEXT_PAUSE_MARKER_SCALE;
  
  /* Animate marker by varying its y position */
  y -= sin(longtext->state.anitime * ALLEGRO_PI) * ms / ZORI_LONGTEXT_PAUSE_MARKER_DAMPER;
  
  if (root->style.icons.paused) { 
    al_draw_bitmap(root->style.icons.paused, x, y, 0);
  } else {   
    y2 = y  + ms;
    x2 = x + longtext->widget.inner.size.x;
    x1 = x2 - ms;
    y1 = y2;
    x3 = x2 - ms / 2.0;
    y3 = y2 + ms;
    al_draw_filled_triangle(x1, y1, x2, y2, x3, y3, longtext->widget.style.text.color);
  }
}


/* This function is the helper callback that implements the actual drawing
 * for zori_longtext_draw_partial_text.
 */
static bool zori_longtext_draw_custom_partial_text(int line_num, const zori_text *line, 
  void *extra) {
  float x, y;
  struct zori_longtext * longtext = extra;  
  ALLEGRO_USTR_INFO info;
  const ALLEGRO_USTR * subline;
  int real_length, flags;
  ALLEGRO_FONT * font;
  BeVec pos;
  int sublength   = al_ustr_length(line);
  int last_line   = line_num;
  int start_line  = longtext->state.page * longtext->settings.lines;
  int stop_line   = longtext->state.line + 1;
  if (stop_line >= longtext->state.total) {
    stop_line = longtext->state.total;
  }
  
  font      = zori_widget_font(&longtext->widget);
  flags     = longtext->widget.style.text.flags | ALLEGRO_ALIGN_INTEGER;
  pos       = zori_longtext_calculate_text_position(longtext);
 

  
  /* Don't draw lines before start but keep on drawing (for later lines) */
  if (line_num < start_line) return true;
  /* Don't draw lines after stop, drawing is done */
  if (line_num >= stop_line) return false;
  
  real_length = sublength;
  
  /* Reveal letter by letter on currently active line */
  if (line_num == (longtext->state.line)) { 
    real_length = (longtext->state.position < sublength) ? longtext->state.position : sublength;
  }
  
  
  x  = pos.x;
  y  = pos.y + (longtext->settings.spacing * (line_num - start_line));

    
  /* calculate position of subline */
  subline = al_ref_ustr(&info, line, 0, al_ustr_offset(line, real_length));

  
  if (flags & ALLEGRO_ALIGN_CENTER) {    
    /* x -= al_get_ustr_width(font, subline) / 2; */
  } else if (flags & ALLEGRO_ALIGN_RIGHT) {
    x -= al_get_ustr_width(font, subline);
  }

  
  
  
  // real_size = size;
  
  zori_color shadow = longtext->widget.style.back.color;
  zori_color fore   = longtext->widget.style.text.color;
  
  al_draw_ustr(font, shadow, x + 1, y + 1, flags, subline);
  al_draw_ustr(font, fore, x, y, flags, subline);
                
  return true;
}


/* Allows to draw a multi line text partially, from line_start up to
 * line_stop. Draws scrolling text from a prefilled struct. */ 
void zori_longtext_draw_partial_text(struct zori_longtext * longtext) {
  float width = longtext->widget.inner.size.x - 20; 
  zori_font * font = zori_widget_font(&longtext->widget);
  
  if (!longtext->text) {
    LOG_WARNING("Trying to draw a NULL longtext.");
    return;
  }
      
  al_do_multiline_ustr(font, width,
      longtext->text, zori_longtext_draw_custom_partial_text, longtext);  
}


void zori_draw_longtext(struct zori_longtext * longtext) {
  zori_widget_draw_background(&longtext->widget);
  zori_longtext_draw_partial_text(longtext);
  zori_longtext_draw_paused_marker(longtext);
}


/** Sets the last line to display for a long text */
zori_id zori_set_line_stop(zori_id index, int stop) {
  return ZORI_ID_EINVAL;
}

/** Sets the first line to display for a long text */
zori_id zori_line_start_(zori_id index, int start) {
  return ZORI_ID_EINVAL;
}

/** Sets display delay between individual characters for a long text */
int zori_delay_(zori_id index, double delay) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL; 
  longtext->settings.delay = delay;
  return index;
}

/** Gets the last line to display for a long text  or negative on error*/
int zori_line_stop(int index) {
  return ZORI_ID_EINVAL;
}

/** Gets the first line to display for a long text */
int zori_line_start(int index) {
  return ZORI_ID_EINVAL;
}

/** Gets display delay between individual characters for a long text */
double zori_delay(int index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;
  return longtext->settings.delay;
}

/** Sets amount of shown lines per page for a long text */
int zori_page_lines_(zori_id index, int lines) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;  
  zori_longtext_page_lines_(longtext, lines);
  return index;
}

/** Gets amount of lines for a "page" of long text */
int zori_page_lines(int index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;
  return zori_longtext_page_lines(longtext);
}

/** Sets paused state of long text */
int zori_paused_(zori_id index, int paused) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;
  longtext->state.paused = paused;
  return index;
}

/** Gets paused state of long text */
int zori_paused(zori_id index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return 0;
  return longtext->state.paused;
}

/** Gets the current text page for a longtext. */
int zori_page(zori_id index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;
  return zori_longtext_page(longtext);
}

/** Gets the number of the last text page for a longtext. */
int zori_last_page(zori_id index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;
  return zori_longtext_last_page(longtext);
}

/** Returns nonzero if the long text is at the end of it's display. */
int zori_at_end(zori_id index) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  if (!longtext) return ZORI_ID_EINVAL;  
  return zori_longtext_at_end(longtext);
}

/** Advances long text to the given page. Automatically unpauses as well. */
int zori_page_(zori_id index, int page) {
  struct zori_widget * widget = zori_get_widget(index);
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  return zori_longtext_page_(longtext, page);
}

/** Advances long text to the next page. Automatically unpauses as well. */
int zori_next_page(zori_id index) {
  int page = zori_page(index);
  if (page < 0) return page;
  return zori_page_(index, page + 1); 
}

/** Advances long text to the previous page. Automatically unpauses as well. */
int zori_previous_page(int index) {
  int page = zori_page(index);
  if (page < 0) return page;
  return zori_page_(index, page - 1); 
}

/** Handles an update event and pass it on. */
int zori_longtext_on_update(union zori_event * event) { 
  struct zori_widget * widget     = event->any.widget;
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);
  zori_longtext_update_longtext(longtext, event->update.dt);

  return ZORI_HANDLE_PASS;
}

/** Handles a mouse axis event and pass it on. */
int zori_longtext_on_mouse_axes(union zori_event * event) { 
    struct zori_widget * widget     = event->any.widget;
    struct zori_longtext * longtext = zori_widget_to_longtext(widget);
    float x = event->sys.ev->mouse.x;
    float y = event->sys.ev->mouse.y;
    if (zori_xy_inside_widget_p(widget, x, y)) {
      zori_widget_hover_(widget, TRUE);
    } else {
      zori_widget_hover_(widget, FALSE);
    }
    
    return ZORI_HANDLE_PASS;
}

/** Handles a mouse click event and pass it on.  */
int zori_longtext_on_mouse_click(union zori_event * event) { 
    struct zori_widget * widget = event->any.widget;
    struct zori_longtext * longtext = zori_widget_to_longtext(widget);
    float x = event->sys.ev->mouse.x;
    float y = event->sys.ev->mouse.y;
    int   b = event->sys.ev->mouse.button;
    if (zori_xy_inside_widget_p(widget, x, y)) {
      struct zori_widget * page = zori_widget_get_parent_of_type(widget, ZORI_WIDGET_TYPE_PAGE); 
      widget->result.ready = widget->id;
      widget->result.value.string = longtext->text;
      LOG_NOTE("Longtext %d clicked: %d, result %d.\n", widget->id, widget->result);
      LOG_NOTE("Longtext visible %d.\n", zori_widget_visible(widget));
      LOG_NOTE("UI page visible %d.\n", zori_widget_visible(page));
      LOG_NOTE("Longtext page visible %d.\n", zori_longtext_page(longtext));
      
      longtext->state.paused = 0;
      
      if (1==b) {
        if (zori_longtext_at_end(longtext)) { 
          zori_widget_set_closed_result(&longtext->widget, longtext->state.total);
        } else {
          zori_longtext_page_(longtext, zori_longtext_page(longtext) + 1);
        }
      } else if (2==b) {
        zori_longtext_page_(longtext, 0);
      }     
      return zori_widget_raise_action_event(widget);
    }
    return ZORI_HANDLE_PASS;
}


int zori_longtext_on_draw(union zori_event * event) {
  struct zori_widget * widget = event->any.widget;
  struct zori_longtext * longtext = zori_widget_to_longtext(widget);  
  zori_draw_longtext(longtext);
  return ZORI_HANDLE_PASS;
}


struct zori_handler zori_longtext_handlers[] = {
  { ZORI_SYSTEM_EVENT_MOUSE_BUTTON_DOWN , zori_longtext_on_mouse_click   , NULL },
  { ZORI_SYSTEM_EVENT_MOUSE_AXES        , zori_longtext_on_mouse_axes    , NULL },
  { ZORI_EVENT_DRAW                     , zori_longtext_on_draw          , NULL },
  { ZORI_EVENT_UPDATE                   , zori_longtext_on_update        , NULL },
  { -1, NULL, NULL }
};


struct zori_longtext * 
zori_longtext_init(struct zori_longtext * longtext, const char * text) {
  if (longtext) {
    int lh = 8;
    zori_longtext_set_cstr(longtext, text);
    zori_longtext_page_(longtext, 0);
    lh = zori_font_lineheight(longtext->widget.style.text.font);
    zori_longtext_page_lines_(longtext, lh / longtext->widget.inner.size.y);
    longtext->settings.delay = ZORI_LONGTEXT_DEFAULT_DELAY;
    longtext->state.line = 0;
    longtext->state.page = 0;
    longtext->state.position = 0;
    longtext->state.paused = 0;
    longtext->state.anitime = 0.0;
    longtext->settings.lines = 2;
    
    /* XXX It's a hack that this ends up here... */
    if (longtext->settings.spacing < 1.0) {
      longtext->settings.spacing = lh;
    }
  }
  return longtext;
}

struct zori_longtext * zori_longtext_new(zori_id id, zori_id parent_id, 
  zori_box * box, const char * text) {
  struct zori_longtext * longtext = NULL;
  longtext = calloc(1, sizeof(*longtext));
  if (!longtext) return NULL;
  zori_widget_initall(&longtext->widget, ZORI_WIDGET_TYPE_LONGTEXT, id, zori_get_widget(parent_id), 
                      box, NULL, ZORI_ARRAY_AND_AMOUNT(zori_longtext_handlers)); 
  if (!zori_longtext_init(longtext, text)) {
    free(longtext);
    longtext = NULL;
  }
  zori_widget_hover_(&longtext->widget, 0);
  zori_widget_live_(&longtext->widget, 1);
  
  return longtext;
}


zori_id zori_new_longtext(zori_id id, zori_id parent, zori_box * box, const char * text) {
  struct zori_longtext * longtext = zori_longtext_new(id, parent, box, text);
  if (!longtext) return ZORI_ID_ENOMEM;
  return longtext->widget.id;
}