/* 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 "asset.h"
#include "cards.h"
#include "layout.h"
#include "stack.h"

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

enum {
	Stock,
	Waste1,
	Waste3,
	Foundation1,
	Foundation2,
	Foundation3,
	Foundation4,
	Tableau1,
	Tableau2,
	Tableau3,
	Tableau4,
	Tableau5,
	Tableau6,
	Tableau7,
	StacksLen,
};

static struct Stack stacks[StacksLen];

// TODO: Scoring method, score, time.
static struct {
	uint draw;
} game = {
	.draw = 3,
};

typedef void StackFn(struct Stack *dst, struct Stack *src, Uint8 len);

static struct {
	StackFn *fn;
	uint dst;
	uint src;
	uint len;
} undo;

static void gameDo(StackFn *fn, uint dst, uint src, uint len) {
	undo.fn = fn;
	undo.dst = src;
	undo.src = dst;
	undo.len = len;
	fn(&stacks[dst], &stacks[src], len);
}

static bool gameUndo(void) {
	if (!undo.fn) return false;
	undo.fn(&stacks[undo.dst], &stacks[undo.src], undo.len);
	undo.fn = NULL;
	return true;
}

static void gameDeal(void) {
	undo.fn = NULL;
	for (uint i = 0; i < StacksLen; ++i) {
		stackClear(&stacks[i]);
	}
	for (Card i = 1; i <= 52; ++i) {
		stackPush(&stacks[Stock], -i);
	}
	stackShuffle(&stacks[Stock]);
	for (uint i = Tableau1; i <= Tableau7; ++i) {
		stackMoveTo(&stacks[i], &stacks[Stock], i - Tableau1);
		stackFlipTo(&stacks[i], &stacks[Stock], 1);
	}
}

static void gameDraw(void) {
	stackMoveTo(&stacks[Waste1], &stacks[Waste3], stacks[Waste3].len);
	if (stacks[Stock].len) {
		if (game.draw > 1) {
			gameDo(stackFlipTo, Waste3, Stock, game.draw);
		} else {
			gameDo(stackFlipTo, Waste1, Stock, 1);
		}
	} else {
		gameDo(stackFlipTo, Stock, Waste1, stacks[Waste1].len);
	}
}

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 (card < 0) return false;
	if (!gameFind(&stack, &index, card)) return false;

	bool top = (card == stackTop(&stacks[stack]));
	if (stack == Waste1) {
		return top && !stacks[Waste3].len;
	} else if (stack == Waste3) {
		return top;
	} else if (stack >= Foundation1 && stack <= Foundation4) {
		return top;
	} else if (stack >= Tableau1 && stack <= Tableau7) {
		return true;
	} else {
		return false;
	}
}

static bool gameReveal(Card card) {
	uint stack, index;
	if (!gameFind(&stack, &index, card)) return false;
	if (stack < Tableau1 || stack > Tableau7) return false;
	if (card != stackTop(&stacks[stack])) return false;
	if (card > 0) return false;
	gameDo(stackFlipTo, stack, stack, 1);
	return true;
}

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

	uint count = stacks[source].len - index;
	Card destTop = stackTop(&stacks[dest]);

	if (dest >= Foundation1 && dest <= Foundation4) {
		if (count > 1) return false;
		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;
		gameDo(stackMoveTo, dest, source, 1);
		return true;
	}

	if (dest >= Tableau1 && dest <= Tableau7) {
		if (!destTop && cardRank(card) != Cards_K) return false;
		if (destTop && cardColor(card) == cardColor(destTop)) return false;
		if (destTop && cardRank(card) != cardRank(destTop) - 1) return false;
		gameDo(stackMoveTo, dest, source, count);
		return true;
	}

	return false;
}

enum {
	CardWidth = Cards_CardWidth,
	CardHeight = Cards_CardHeight,

	StackMarginX = 11,
	StackMarginY = 6,

	StockX = StackMarginX,
	StockY = StackMarginY,

	WasteX = StockX + CardWidth + StackMarginX,
	WasteY = StackMarginY,

	FoundationX = WasteX + 2 * (CardWidth + StackMarginX),
	FoundationY = StackMarginY,

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

	FanRightDeltaX = 14,
	FanDownDeltaYBack = 3,
	FanDownDeltaYFront = 15,

	WindowWidth = 7 * CardWidth + 8 * StackMarginX,
	WindowHeight = 2 * (StackMarginY + CardHeight)
		+ 6 * FanDownDeltaYBack
		+ 12 * FanDownDeltaYFront
		+ StackMarginY,
};

static const struct Style FanRight = {
	1, 0, 0, FanRightDeltaX, SquareDeltaY
};
static const struct Style FanDown = {
	1, 0, FanDownDeltaYBack, 0, FanDownDeltaYFront
};

static struct SDL_Rect stackRects[StacksLen];
static struct Layout layout;
static uint backTexture = Cards_Back1;

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

	SDL_Rect stock = { StockX, StockY, CardWidth, CardHeight };
	stackRects[Stock] = stock;
	listPush(&layout.main, &stock, Cards_O);
	layoutStack(&layout, &stock, &stacks[Stock], &Square);

	SDL_Rect waste = { WasteX, WasteY, CardWidth, CardHeight };
	layoutStack(&layout, &waste, &stacks[Waste1], &Square);
	layoutStack(&layout, &waste, &stacks[Waste3], &FanRight);

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

	SDL_Rect table = { TableauX, TableauY, CardWidth, CardHeight };
	for (uint i = Tableau1; i <= Tableau7; ++i) {
		stackRects[i] = table;
		stackRects[i].h = WindowHeight;
		SDL_Rect rect = table;
		layoutStack(&layout, &rect, &stacks[i], &FanDown);
		table.x += CardWidth + StackMarginX;
	}
}

static bool keyDown(SDL_KeyboardEvent key) {
	switch (key.keysym.sym) {
		case SDLK_F2: gameDeal(); return true;
		case SDLK_BACKSPACE: return gameUndo();
		case SDLK_b: {
			backTexture -= Cards_Back1;
			backTexture += 1;
			backTexture %= 12;
			backTexture += Cards_Back1;
			return true;
		}
		case SDLK_d: {
			game.draw = (game.draw == 1 ? 3 : 1);
			gameDeal();
			return true;
		}
		default: return false;
	}
}

static bool mouseButtonDown(SDL_MouseButtonEvent button) {
	struct SDL_Point point = { button.x, button.y };
	if (SDL_PointInRect(&point, &stackRects[Stock])) {
		gameDraw();
		return true;
	}
	struct Item *item = listFind(&layout.main, &point);
	if (!item) return false;
	if (!gameAvail(item->card)) return gameReveal(item->card);
	if (button.clicks % 2 == 0) {
		for (uint dest = Foundation1; dest <= Foundation4; ++dest) {
			if (gameMove(dest, item->card)) return true;
		}
		return false;
	}
	layout.dragItem = *item;
	return true;
}

static bool mouseButtonUp(SDL_MouseButtonEvent button) {
	(void)button;
	if (!layout.dragItem.card) return false;
	for (uint dest = 0; dest < StacksLen; ++dest) {
		if (SDL_HasIntersection(&layout.dragItem.rect, &stackRects[dest])) {
			if (gameMove(dest, layout.dragItem.card)) break;
		}
	}
	layout.dragItem.card = 0;
	return true;
}

static bool mouseMotion(SDL_MouseMotionEvent motion) {
	if (!motion.state) return false;
	layout.dragItem.rect.x += motion.xrel;
	layout.dragItem.rect.y += motion.yrel;
	return true;
}

static SDL_Renderer *render;
static SDL_Texture *textures[Cards_CardCount];

static void renderList(const struct List *list) {
	for (uint i = 0; i < list->len; ++i) {
		int tex = list->items[i].card;
		if (tex < 0) tex = backTexture;
		SDL_RenderCopy(render, textures[tex], 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);

	struct Paths paths;
	if (assetPaths(&paths) < 0) err("SDL_GetPrefPath");

	SDL_RWops *rw = assetOpenCards(&paths);
	if (!rw) return EXIT_FAILURE;

	SDL_Surface *surfaces[Cards_CardCount];
	int error = Cards_LoadCards(
		surfaces, Cards_CardCount,
		rw, Cards_ColorKey | 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, "Solitaire");

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

	for (uint i = 0; i < Cards_CardCount; ++i) {
		textures[i] = NULL;
		if (!surfaces[i]) continue;
		textures[i] = SDL_CreateTextureFromSurface(render, surfaces[i]);
		if (!textures[i]) err("SDL_CreateTextureFromSurface");
		SDL_FreeSurface(surfaces[i]);
	}

	srand(time(NULL));
	backTexture = Cards_Back1 + randUniform(12);
	gameDeal();

	for (;;) {
		updateLayout();

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

		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_MOUSEBUTTONDOWN) {
				if (mouseButtonDown(event.button)) break;
			} else if (event.type == SDL_MOUSEBUTTONUP) {
				if (mouseButtonUp(event.button)) break;
			} else if (event.type == SDL_MOUSEMOTION) {
				if (mouseMotion(event.motion)) break;
			}
		}
	}

quit:
	SDL_Quit();
}