/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <SDL.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#include "cards.h"
#include "layout.h"
#include "path.h"
#include "stack.h"

#define ARRAY_LEN(a) (sizeof(a) / sizeof((a)[0]))

enum {
	Foundation1,
	Foundation2,
	Foundation3,
	Foundation4,
	Cell1,
	Cell2,
	Cell3,
	Cell4,
	Tableau1,
	Tableau2,
	Tableau3,
	Tableau4,
	Tableau5,
	Tableau6,
	Tableau7,
	Tableau8,
	StacksLen,
};

static struct Stack stacks[StacksLen];

static void gameDeal(void) {
	for (uint i = 0; i < StacksLen; ++i) {
		stackClear(&stacks[i]);
	}
	struct Stack deck = {0};
	for (Card i = 1; i <= 52; ++i) {
		stackPush(&deck, i);
	}
	stackShuffle(&deck);
	for (uint i = Tableau1; i <= Tableau4; ++i) {
		stackMoveTo(&stacks[i], &deck, 7);
	}
	for (uint i = Tableau5; i <= Tableau8; ++i) {
		stackMoveTo(&stacks[i], &deck, 6);
	}
}

static bool gameFind(uint *stack, uint *index, Card card) {
	for (*stack = 0; *stack < StacksLen; ++*stack) {
		for (*index = 0; *index < stacks[*stack].len; ++*index) {
			if (stacks[*stack].cards[*index] == card) return true;
		}
	}
	return false;
}

static bool gameAvail(Card card) {
	uint stack, index;
	if (!gameFind(&stack, &index, card)) return false;
	if (stack >= Foundation1 && stack <= Foundation4) return false;
	return card == stackTop(&stacks[stack]);
}

static bool gameMove(uint dest, Card card) {
	uint source, index;
	if (!gameFind(&source, &index, card)) return false;
	Card destTop = stackTop(&stacks[dest]);

	if (source == dest) return false;
	if (dest >= Cell1 && dest <= Cell4) {
		if (stacks[dest].len) return false;
	}
	if (dest >= Foundation1 && dest <= Foundation4) {
		if (!destTop && cardRank(card) != Cards_A) return false;
		if (destTop && cardSuit(card) != cardSuit(destTop)) return false;
		if (destTop && cardRank(card) != cardRank(destTop) + 1) return false;
	}
	if (dest >= Tableau1 && dest <= Tableau8) {
		if (destTop && cardColor(card) == cardColor(destTop)) return false;
		if (destTop && cardRank(card) != cardRank(destTop) - 1) return false;
	}

	stackPush(&stacks[dest], stackPop(&stacks[source]));
	return true;
}

static bool gameAuto(void) {
	Card min[2] = { Cards_K, Cards_K };
	for (uint i = Cell1; i <= Tableau8; ++i) {
		for (uint j = 0; j < stacks[i].len; ++j) {
			Card card = stacks[i].cards[j];
			if (cardRank(card) < min[cardColor(card)]) {
				min[cardColor(card)] = cardRank(card);
			}
		}
	}
	for (uint i = Cell1; i <= Tableau8; ++i) {
		Card card = stackTop(&stacks[i]);
		if (!card) continue;
		if (cardRank(card) > Cards_2) {
			if (min[!cardColor(card)] < cardRank(card)) continue;
		}
		for (uint dest = Foundation1; dest <= Foundation4; ++dest) {
			if (gameMove(dest, card)) return true;
		}
	}
	return false;
}

enum {
	CardWidth = Cards_CardWidth,
	CardHeight = Cards_CardHeight,

	StackMarginX = 7,
	StackMarginY = 10,

	CellX = 0,
	CellY = 0,

	CellsMarginX = 64,

	FoundationX = CellX + 4 * CardWidth + CellsMarginX,
	FoundationY = CellY,

	TableauX = StackMarginX,
	TableauY = CellY + CardHeight + StackMarginY,

	FanDownDeltaY = 17,

	WindowWidth = 8 * CardWidth + 9 * StackMarginX + 1,
	WindowHeight = TableauY + CardHeight
		+ 13 * FanDownDeltaY
		+ StackMarginY,
};

static const struct Style FanDown = { 1, 0, 0, 0, FanDownDeltaY };

static struct SDL_Rect stackRects[StacksLen];
static struct Layout layout;
static struct List reveal;

static void updateLayout(void) {
	layoutClear(&layout);

	SDL_Rect cell = { CellX, CellY, CardWidth, CardHeight };
	for (uint i = Cell1; i <= Cell4; ++i) {
		stackRects[i] = cell;
		layoutStack(&layout, &cell, &stacks[i], &Flat);
		cell.x += CardWidth;
	}

	SDL_Rect found = { FoundationX, FoundationY, CardWidth, CardHeight };
	for (uint i = Foundation1; i <= Foundation4; ++i) {
		stackRects[i] = found;
		layoutStack(&layout, &found, &stacks[i], &Flat);
		found.x += CardWidth;
	}

	SDL_Rect table = { TableauX, TableauY, CardWidth, CardHeight };
	for (uint i = Tableau1; i <= Tableau8; ++i) {
		stackRects[i] = table;
		stackRects[i].h = WindowHeight;
		SDL_Rect rect = table;
		layoutStack(&layout, &rect, &stacks[i], &FanDown);
		table.x += CardWidth + StackMarginX;
	}
}

static void revealRank(Card rank) {
	for (uint i = 0; i < layout.main.len; ++i) {
		struct Item item = layout.main.items[i];
		if (cardRank(item.card) != rank) continue;
		listPush(&reveal, &item.rect, item.card);
	}
}

static bool keyDown(SDL_KeyboardEvent key) {
	switch (key.keysym.sym) {
		case SDLK_F2: gameDeal(); return true;
	}
	if (key.repeat) return false;
	switch (key.keysym.sym) {
		break; case SDLK_a: revealRank(Cards_A);
		break; case SDLK_2: revealRank(Cards_2);
		break; case SDLK_3: revealRank(Cards_3);
		break; case SDLK_4: revealRank(Cards_4);
		break; case SDLK_5: revealRank(Cards_5);
		break; case SDLK_6: revealRank(Cards_6);
		break; case SDLK_7: revealRank(Cards_7);
		break; case SDLK_8: revealRank(Cards_8);
		break; case SDLK_9: revealRank(Cards_9);
		break; case SDLK_1: revealRank(Cards_10);
		break; case SDLK_0: revealRank(Cards_10);
		break; case SDLK_j: revealRank(Cards_J);
		break; case SDLK_q: revealRank(Cards_Q);
		break; case SDLK_k: revealRank(Cards_K);
		break; default: return false;
	}
	return true;
}

static bool keyUp(SDL_KeyboardEvent key) {
	(void)key;
	if (!reveal.len) return false;
	reveal.len = 0;
	return true;
}

static bool mouseButtonDown(SDL_MouseButtonEvent button) {
	struct SDL_Point point = { button.x, button.y };
	struct Item *item = listFind(&layout.main, &point);

	if (button.button == SDL_BUTTON_RIGHT) {
		if (!item) return false;
		listPush(&reveal, &item->rect, item->card);
		return true;
	}

	if (button.clicks % 2 == 0) {
		Card card = layout.dragItem.card;
		if (!card) {
			if (!item) return false;
			card = item->card;
		}
		for (uint dest = Cell1; dest <= Cell4; ++dest) {
			if (gameMove(dest, card)) break;
		}
		layout.dragItem.card = 0;
		return true;
	}

	if (layout.dragItem.card) {
		for (uint dest = 0; dest < StacksLen; ++dest) {
			if (SDL_PointInRect(&point, &stackRects[dest])) {
				if (gameMove(dest, layout.dragItem.card)) break;
			}
		}
		layout.dragItem.card = 0;
		return true;
	}

	if (!item) return false;
	if (!gameAvail(item->card)) return false;
	layout.dragItem = *item;
	return true;
}

static bool mouseButtonUp(SDL_MouseButtonEvent button) {
	if (button.button == SDL_BUTTON_RIGHT) {
		if (!reveal.len) return false;
		reveal.len = 0;
		return true;
	}
	return false;
}

static SDL_Renderer *render;

static void renderOutlines(void) {
	for (uint i = Foundation1; i <= Cell4; ++i) {
		int right = stackRects[i].x + CardWidth - 1;
		int bottom = stackRects[i].y + CardHeight - 1;
		SDL_Point black[3] = {
			{ stackRects[i].x, bottom - 1 },
			{ stackRects[i].x, stackRects[i].y },
			{ right - 1, stackRects[i].y },
		};
		SDL_Point green[3] = {
			{ stackRects[i].x + 1, bottom },
			{ right, bottom },
			{ right, stackRects[i].y + 1 },
		};
		SDL_SetRenderDrawColor(render, 0x00, 0x00, 0x00, 0xFF);
		SDL_RenderDrawLines(render, black, 3);
		SDL_SetRenderDrawColor(render, 0x00, 0xFF, 0x00, 0xFF);
		SDL_RenderDrawLines(render, green, 3);
	}
}

static void renderList(SDL_Texture **textures, const struct List *list) {
	for (uint i = 0; i < list->len; ++i) {
		SDL_RenderCopy(
			render, textures[list->items[i].card],
			NULL, &list->items[i].rect
		);
	}
}

static void err(const char *title) {
	int error = SDL_ShowSimpleMessageBox(
		SDL_MESSAGEBOX_ERROR, title, SDL_GetError(), NULL
	);
	if (error) fprintf(stderr, "%s\n", SDL_GetError());
	exit(EXIT_FAILURE);
}

int main(void) {
	if (SDL_Init(SDL_INIT_VIDEO) < 0) err("SDL_Init");
	atexit(SDL_Quit);

	char *basePath = SDL_GetBasePath();
	if (!basePath) err("SDL_GetBasePath");

	char *prefPath = SDL_GetPrefPath("Causal Agency", "Cards");
	if (!prefPath) err("SDL_GetPrefPath");

	SDL_RWops *rw = pathCards(basePath, prefPath);
	if (!rw) return EXIT_FAILURE;

	SDL_Surface *surfaces[Cards_Empty];
	int error = Cards_LoadCards(
		surfaces, Cards_Empty,
		rw, Cards_AlphaCorners | Cards_BlackBorders
	);
	if (error) err("Cards_LoadCards");
	SDL_RWclose(rw);

	SDL_Window *window;
	error = SDL_CreateWindowAndRenderer(
		WindowWidth, WindowHeight, SDL_WINDOW_ALLOW_HIGHDPI,
		&window, &render
	);
	if (error) err("SDL_CreateWindowAndRenderer");
	SDL_SetWindowTitle(window, "FreeCell");

	SDL_RenderSetIntegerScale(render, SDL_TRUE);
	SDL_RenderSetLogicalSize(render, WindowWidth, WindowHeight);

	SDL_Texture *textures[Cards_Empty];
	SDL_Texture *inverted[Cards_Empty];
	for (uint i = 0; i < Cards_Empty; ++i) {
		textures[i] = NULL;
		inverted[i] = NULL;
		if (!surfaces[i]) continue;

		textures[i] = SDL_CreateTextureFromSurface(render, surfaces[i]);
		if (!textures[i]) err("SDL_CreateTextureFromSurface");

		if (Cards_InvertSurface(surfaces[i]) < 0) err("Cards_InvertSurface");
		inverted[i] = SDL_CreateTextureFromSurface(render, surfaces[i]);
		if (!inverted[i]) err("SDL_CreateTextureFromSurface");

		SDL_FreeSurface(surfaces[i]);
	}

	srand(time(NULL));
	gameDeal();

	for (;;) {
		updateLayout();

		SDL_SetRenderDrawColor(render, 0x00, 0xAA, 0x55, 0xFF);
		SDL_RenderClear(render);
		renderOutlines();
		renderList(textures, &layout.main);
		renderList(inverted, &layout.drag);
		renderList(textures, &reveal);
		SDL_RenderPresent(render);

		// TODO: Add more than a frame delay between automatic moves?
		if (gameAuto()) continue;

		SDL_Event event;
		for (;;) {
			SDL_WaitEvent(&event);
			if (event.type == SDL_QUIT) {
				goto quit;
			} else if (event.type == SDL_KEYDOWN) {
				if (keyDown(event.key)) break;
			} else if (event.type == SDL_KEYUP) {
				if (keyUp(event.key)) break;
			} else if (event.type == SDL_MOUSEBUTTONDOWN) {
				if (mouseButtonDown(event.button)) break;
			} else if (event.type == SDL_MOUSEBUTTONUP) {
				if (mouseButtonUp(event.button)) break;
			}
		}
	}

quit:
	SDL_Quit();
}