#include <stdio.h>
#include <string.h>
#include <regex.h>
#include "vis-core.h"
#include "text-motions.h"
#include "text-objects.h"
#include "text-util.h"
#include "util.h"

static Regex *search_word(Vis *vis, Text *txt, size_t pos) {
	char expr[512];
	Filerange word = text_object_word(txt, pos);
	if (!text_range_valid(&word))
		return NULL;
	char *buf = text_bytes_alloc0(txt, word.start, text_range_size(&word));
	if (!buf)
		return NULL;
	snprintf(expr, sizeof(expr), "[[:<:]]%s[[:>:]]", buf);
	Regex *regex = vis_regex(vis, expr);
	if (!regex) {
		snprintf(expr, sizeof(expr), "\\<%s\\>", buf);
		regex = vis_regex(vis, expr);
	}
	free(buf);
	return regex;
}

static size_t search_word_forward(Vis *vis, Text *txt, size_t pos) {
	Regex *regex = search_word(vis, txt, pos);
	if (regex)
		pos = text_search_forward(txt, pos, regex);
	text_regex_free(regex);
	return pos;
}

static size_t search_word_backward(Vis *vis, Text *txt, size_t pos) {
	Regex *regex = search_word(vis, txt, pos);
	if (regex)
		pos = text_search_backward(txt, pos, regex);
	text_regex_free(regex);
	return pos;
}

static size_t search_forward(Vis *vis, Text *txt, size_t pos) {
	Regex *regex = vis_regex(vis, NULL);
	if (regex)
		pos = text_search_forward(txt, pos, regex);
	text_regex_free(regex);
	return pos;
}

static size_t search_backward(Vis *vis, Text *txt, size_t pos) {
	Regex *regex = vis_regex(vis, NULL);
	if (regex)
		pos = text_search_backward(txt, pos, regex);
	text_regex_free(regex);
	return pos;
}

static size_t mark_goto(Vis *vis, File *file, size_t pos) {
	return text_mark_get(file->text, file->marks[vis->action.mark]);
}

static size_t mark_line_goto(Vis *vis, File *file, size_t pos) {
	return text_line_start(file->text, mark_goto(vis, file, pos));
}

static size_t to(Vis *vis, Text *txt, size_t pos) {
	char c;
	if (pos == text_line_end(txt, pos))
		return pos;
	size_t hit = text_line_find_next(txt, pos+1, vis->search_char);
	if (!text_byte_get(txt, hit, &c) || c != vis->search_char[0])
		return pos;
	return hit;
}

static size_t till(Vis *vis, Text *txt, size_t pos) {
	size_t hit = to(vis, txt, pos+1);
	if (pos == text_line_end(txt, pos))
		return pos;
	if (hit != pos)
		return text_char_prev(txt, hit);
	return pos;
}

static size_t to_left(Vis *vis, Text *txt, size_t pos) {
	return text_line_find_prev(txt, pos, vis->search_char);
}

static size_t till_left(Vis *vis, Text *txt, size_t pos) {
	if (pos == text_line_begin(txt, pos))
		return pos;
	size_t hit = to_left(vis, txt, pos-1);
	if (hit != pos-1)
		return text_char_next(txt, hit);
	return pos;
}

static size_t firstline(Text *txt, size_t pos) {
	return text_line_start(txt, 0);
}

static size_t line(Vis *vis, Text *txt, size_t pos) {
	int count = vis_count_get_default(vis, 1);
	return text_line_start(txt, text_pos_by_lineno(txt, count));
}

static size_t lastline(Text *txt, size_t pos) {
	pos = text_size(txt);
	return text_line_start(txt, pos > 0 ? pos-1 : pos);
}

static size_t column(Vis *vis, Text *txt, size_t pos) {
	return text_line_offset(txt, pos, vis_count_get_default(vis, 0));
}

static size_t view_lines_top(Vis *vis, View *view) {
	return view_screenline_goto(view, vis_count_get_default(vis, 1));
}

static size_t view_lines_middle(Vis *vis, View *view) {
	int h = view_height_get(view);
	return view_screenline_goto(view, h/2);
}

static size_t view_lines_bottom(Vis *vis, View *view) {
	int h = view_height_get(vis->win->view);
	return view_screenline_goto(vis->win->view, h - vis_count_get_default(vis, 0));
}

static size_t window_changelist_next(Vis *vis, Win *win, size_t pos) {
	ChangeList *cl = &win->changelist;
	Text *txt = win->file->text;
	time_t state = text_state(txt);
	if (cl->state != state)
		cl->index = 0;
	else if (cl->index > 0 && pos == cl->pos)
		cl->index--;
	size_t newpos = text_history_get(txt, cl->index);
	if (newpos == EPOS)
		cl->index++;
	else
		cl->pos = newpos;
	cl->state = state;
	return cl->pos;
}

static size_t window_changelist_prev(Vis *vis, Win *win, size_t pos) {
	ChangeList *cl = &win->changelist;
	Text *txt = win->file->text;
	time_t state = text_state(txt);
	if (cl->state != state)
		cl->index = 0;
	else if (pos == cl->pos)
		win->changelist.index++;
	size_t newpos = text_history_get(txt, cl->index);
	if (newpos == EPOS)
		cl->index--;
	else
		cl->pos = newpos;
	cl->state = state;
	return cl->pos;
}

static size_t window_jumplist_next(Vis *vis, Win *win, size_t cur) {
	while (win->jumplist) {
		Mark mark = ringbuf_next(win->jumplist);
		if (!mark)
			return cur;
		size_t pos = text_mark_get(win->file->text, mark);
		if (pos != EPOS && pos != cur)
			return pos;
	}
	return cur;
}

static size_t window_jumplist_prev(Vis *vis, Win *win, size_t cur) {
	while (win->jumplist) {
		Mark mark = ringbuf_prev(win->jumplist);
		if (!mark)
			return cur;
		size_t pos = text_mark_get(win->file->text, mark);
		if (pos != EPOS && pos != cur)
			return pos;
	}
	return cur;
}

static size_t window_nop(Vis *vis, Win *win, size_t pos) {
	return pos;
}

static size_t bracket_match(Text *txt, size_t pos) {
	size_t hit = text_bracket_match_symbol(txt, pos, "(){}[]<>");
	if (hit != pos)
		return hit;
	char current;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_get(&it, &current)) {
		switch (current) {
		case '(':
		case ')':
		case '{':
		case '}':
		case '[':
		case ']':
		case '<':
		case '>':
			return it.pos;
		}
		text_iterator_byte_next(&it, NULL);
	}
	return pos;
}

static size_t percent(Vis *vis, Text *txt, size_t pos) {
	int ratio = vis_count_get_default(vis, 0);
	if (ratio > 100)
		ratio = 100;
	return text_size(txt) * ratio / 100;
}

void vis_motion_type(Vis *vis, enum VisMotionType type) {
	vis->action.type = type;
}

int vis_motion_register(Vis *vis, enum VisMotionType type, void *data,
	size_t (*motion)(Vis*, Win*, void*, size_t pos)) {

	Movement *move = calloc(1, sizeof *move);
	if (!move)
		return -1;

	move->user = motion;
	move->type = type;
	move->data = data;

	if (array_add_ptr(&vis->motions, move))
		return VIS_MOVE_LAST + array_length(&vis->motions) - 1;
	free(move);
	return -1;
}

bool vis_motion(Vis *vis, enum VisMotion motion, ...) {
	va_list ap;
	va_start(ap, motion);

	switch (motion) {
	case VIS_MOVE_WORD_START_NEXT:
		if (vis->action.op == &vis_operators[VIS_OP_CHANGE])
			motion = VIS_MOVE_WORD_END_NEXT;
		break;
	case VIS_MOVE_LONGWORD_START_NEXT:
		if (vis->action.op == &vis_operators[VIS_OP_CHANGE])
			motion = VIS_MOVE_LONGWORD_END_NEXT;
		break;
	case VIS_MOVE_SEARCH_FORWARD:
	case VIS_MOVE_SEARCH_BACKWARD:
	{
		const char *pattern = va_arg(ap, char*);
		Regex *regex = vis_regex(vis, pattern);
		if (!regex) {
			vis_cancel(vis);
			goto err;
		}
		text_regex_free(regex);
		if (motion == VIS_MOVE_SEARCH_FORWARD)
			motion = VIS_MOVE_SEARCH_NEXT;
		else
			motion = VIS_MOVE_SEARCH_PREV;
		break;
	}
	case VIS_MOVE_RIGHT_TO:
	case VIS_MOVE_LEFT_TO:
	case VIS_MOVE_RIGHT_TILL:
	case VIS_MOVE_LEFT_TILL:
	{
		const char *key = va_arg(ap, char*);
		if (!key)
			goto err;
		strncpy(vis->search_char, key, sizeof(vis->search_char));
		vis->search_char[sizeof(vis->search_char)-1] = '\0';
		vis->last_totill = motion;
		break;
	}
	case VIS_MOVE_TOTILL_REPEAT:
		if (!vis->last_totill)
			goto err;
		motion = vis->last_totill;
		break;
	case VIS_MOVE_TOTILL_REVERSE:
		switch (vis->last_totill) {
		case VIS_MOVE_RIGHT_TO:
			motion = VIS_MOVE_LEFT_TO;
			break;
		case VIS_MOVE_LEFT_TO:
			motion = VIS_MOVE_RIGHT_TO;
			break;
		case VIS_MOVE_RIGHT_TILL:
			motion = VIS_MOVE_LEFT_TILL;
			break;
		case VIS_MOVE_LEFT_TILL:
			motion = VIS_MOVE_RIGHT_TILL;
			break;
		default:
			goto err;
		}
		break;
	case VIS_MOVE_MARK:
	case VIS_MOVE_MARK_LINE:
	{
		int mark = va_arg(ap, int);
		if (VIS_MARK_a <= mark && mark < VIS_MARK_INVALID)
			vis->action.mark = mark;
		else
			goto err;
		break;
	}
	default:
		break;
	}

	if (motion < LENGTH(vis_motions))
		vis->action.movement = &vis_motions[motion];
	else
		vis->action.movement = array_get_ptr(&vis->motions, motion - VIS_MOVE_LAST);

	if (!vis->action.movement)
		goto err;

	va_end(ap);
	vis_do(vis);
	return true;
err:
	va_end(ap);
	return false;
}

const Movement vis_motions[] = {
	[VIS_MOVE_LINE_UP] = {
		.cur = view_line_up,
		.type = LINEWISE|LINEWISE_INCLUSIVE,
	},
	[VIS_MOVE_LINE_DOWN] = {
		.cur = view_line_down,
		.type = LINEWISE|LINEWISE_INCLUSIVE,
	},
	[VIS_MOVE_SCREEN_LINE_UP] = {
		.cur = view_screenline_up,
	},
	[VIS_MOVE_SCREEN_LINE_DOWN] = {
		.cur = view_screenline_down,
	},
	[VIS_MOVE_SCREEN_LINE_BEGIN] = {
		.cur = view_screenline_begin,
		.type = CHARWISE,
	},
	[VIS_MOVE_SCREEN_LINE_MIDDLE] = {
		.cur = view_screenline_middle,
		.type = CHARWISE,
	},
	[VIS_MOVE_SCREEN_LINE_END] = {
		.cur = view_screenline_end,
		.type = CHARWISE|INCLUSIVE,
	},
	[VIS_MOVE_LINE_PREV] = {
		.txt = text_line_prev,
	},
	[VIS_MOVE_LINE_BEGIN] = {
		.txt = text_line_begin,
	},
	[VIS_MOVE_LINE_START] = {
		.txt = text_line_start,
	},
	[VIS_MOVE_LINE_FINISH] = {
		.txt = text_line_finish,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_LINE_LASTCHAR] = {
		.txt = text_line_lastchar,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_LINE_END] = {
		.txt = text_line_end,
	},
	[VIS_MOVE_LINE_NEXT] = {
		.txt = text_line_next,
	},
	[VIS_MOVE_LINE] = {
		.vis = line,
		.type = LINEWISE|IDEMPOTENT|JUMP,
	},
	[VIS_MOVE_COLUMN] = {
		.vis = column,
		.type = CHARWISE|IDEMPOTENT,
	},
	[VIS_MOVE_CHAR_PREV] = {
		.txt = text_char_prev,
		.type = CHARWISE,
	},
	[VIS_MOVE_CHAR_NEXT] = {
		.txt = text_char_next,
		.type = CHARWISE,
	},
	[VIS_MOVE_LINE_CHAR_PREV] = {
		.txt = text_line_char_prev,
		.type = CHARWISE,
	},
	[VIS_MOVE_LINE_CHAR_NEXT] = {
		.txt = text_line_char_next,
		.type = CHARWISE,
	},
	[VIS_MOVE_WORD_START_PREV] = {
		.txt = text_word_start_prev,
		.type = CHARWISE,
	},
	[VIS_MOVE_WORD_START_NEXT] = {
		.txt = text_word_start_next,
		.type = CHARWISE,
	},
	[VIS_MOVE_WORD_END_PREV] = {
		.txt = text_word_end_prev,
		.type = CHARWISE|INCLUSIVE,
	},
	[VIS_MOVE_WORD_END_NEXT] = {
		.txt = text_word_end_next,
		.type = CHARWISE|INCLUSIVE,
	},
	[VIS_MOVE_LONGWORD_START_PREV] = {
		.txt = text_longword_start_prev,
		.type = CHARWISE,
	},
	[VIS_MOVE_LONGWORD_START_NEXT] = {
		.txt = text_longword_start_next,
		.type = CHARWISE,
	},
	[VIS_MOVE_LONGWORD_END_PREV] = {
		.txt = text_longword_end_prev,
		.type = CHARWISE|INCLUSIVE,
	},
	[VIS_MOVE_LONGWORD_END_NEXT] = {
		.txt = text_longword_end_next,
		.type = CHARWISE|INCLUSIVE,
	},
	[VIS_MOVE_SENTENCE_PREV] = {
		.txt = text_sentence_prev,
		.type = CHARWISE,
	},
	[VIS_MOVE_SENTENCE_NEXT] = {
		.txt = text_sentence_next,
		.type = CHARWISE,
	},
	[VIS_MOVE_PARAGRAPH_PREV] = {
		.txt = text_paragraph_prev,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_PARAGRAPH_NEXT] = {
		.txt = text_paragraph_next,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_FUNCTION_START_PREV] = {
		.txt = text_function_start_prev,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_FUNCTION_START_NEXT] = {
		.txt = text_function_start_next,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_FUNCTION_END_PREV] = {
		.txt = text_function_end_prev,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_FUNCTION_END_NEXT] = {
		.txt = text_function_end_next,
		.type = LINEWISE|JUMP,
	},
	[VIS_MOVE_BLOCK_START] = {
		.txt = text_block_start,
		.type = JUMP,
	},
	[VIS_MOVE_BLOCK_END] = {
		.txt = text_block_end,
		.type = JUMP,
	},
	[VIS_MOVE_PARENTHESE_START] = {
		.txt = text_parenthese_start,
		.type = JUMP,
	},
	[VIS_MOVE_PARENTHESE_END] = {
		.txt = text_parenthese_end,
		.type = JUMP,
	},
	[VIS_MOVE_BRACKET_MATCH] = {
		.txt = bracket_match,
		.type = INCLUSIVE|JUMP,
	},
	[VIS_MOVE_FILE_BEGIN] = {
		.txt = firstline,
		.type = LINEWISE|LINEWISE_INCLUSIVE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_FILE_END] = {
		.txt = lastline,
		.type = LINEWISE|LINEWISE_INCLUSIVE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_LEFT_TO] = {
		.vis = to_left,
	},
	[VIS_MOVE_RIGHT_TO] = {
		.vis = to,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_LEFT_TILL] = {
		.vis = till_left,
	},
	[VIS_MOVE_RIGHT_TILL] = {
		.vis = till,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_MARK] = {
		.file = mark_goto,
		.type = JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_MARK_LINE] = {
		.file = mark_line_goto,
		.type = LINEWISE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_SEARCH_WORD_FORWARD] = {
		.vis = search_word_forward,
		.type = JUMP,
	},
	[VIS_MOVE_SEARCH_WORD_BACKWARD] = {
		.vis = search_word_backward,
		.type = JUMP,
	},
	[VIS_MOVE_SEARCH_NEXT] = {
		.vis = search_forward,
		.type = JUMP,
	},
	[VIS_MOVE_SEARCH_PREV] = {
		.vis = search_backward,
		.type = JUMP,
	},
	[VIS_MOVE_WINDOW_LINE_TOP] = {
		.view = view_lines_top,
		.type = LINEWISE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_WINDOW_LINE_MIDDLE] = {
		.view = view_lines_middle,
		.type = LINEWISE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_WINDOW_LINE_BOTTOM] = {
		.view = view_lines_bottom,
		.type = LINEWISE|JUMP|IDEMPOTENT,
	},
	[VIS_MOVE_CHANGELIST_NEXT] = {
		.win = window_changelist_next,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_CHANGELIST_PREV] = {
		.win = window_changelist_prev,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_JUMPLIST_NEXT] = {
		.win = window_jumplist_next,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_JUMPLIST_PREV] = {
		.win = window_jumplist_prev,
		.type = INCLUSIVE,
	},
	[VIS_MOVE_NOP] = {
		.win = window_nop,
		.type = IDEMPOTENT,
	},
	[VIS_MOVE_PERCENT] = {
		.vis = percent,
		.type = IDEMPOTENT,
	},
};