#include <assert.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <wayland-client-protocol.h>

#include "dulcepan.h"
#include "viewporter-protocol.h"
#include "wlr-layer-shell-unstable-v1-protocol.h"
#include "wlr-screencopy-unstable-v1-protocol.h"

// Initialiation flow:
// - Wait for mode+transform info
// - Wait for done, compute transformed size
// - Prepare surfaces, get a frame, wait for it to be ready
// - Commit the main surface, wait for a configure event
// - Save effective size, put the frame buffer on the main surface
// - The output is initialized

static void layer_surface_handle_configure(void *data, struct zwlr_layer_surface_v1 *layer_surface,
		uint32_t serial, uint32_t width, uint32_t height) {
	struct dp_output *output = data;

	if (!output->has_frame) {
		// Ignore configures that came too early
		return;
	}

	// Thanks layer-shell
	int i_width = (int)width, i_height = (int)height;

	zwlr_layer_surface_v1_ack_configure(layer_surface, serial);

	if (output->initialized) {
		if (i_width != output->effective_width || i_height != output->effective_height) {
			dp_log_fatal("Layer surface size has changed: %dx%d => %dx%d", output->effective_width,
					output->effective_height, i_width, i_height);
		}

		wl_surface_commit(output->main_surface);
		return;
	}

	output->effective_width = (int)width;
	output->effective_height = (int)height;

	wp_viewport_set_destination(
			output->main_viewport, output->effective_width, output->effective_height);
	wp_viewport_set_destination(
			output->select_viewport, output->effective_width, output->effective_height);

	if (output->y_invert) {
		wl_surface_set_buffer_transform(output->main_surface, WL_OUTPUT_TRANSFORM_FLIPPED_180);
	}

	wl_surface_attach(output->main_surface, output->frame_buffer, 0, 0);
	wl_surface_commit(output->main_surface);

	output->initialized = true;
}

static void layer_surface_handle_closed(void *data, struct zwlr_layer_surface_v1 *layer_surface) {
	dp_log_fatal("A layer surface was closed");
}

static const struct zwlr_layer_surface_v1_listener layer_surface_listener = {
	.configure = layer_surface_handle_configure,
	.closed = layer_surface_handle_closed,
};

static void frame_handle_buffer(void *data, struct zwlr_screencopy_frame_v1 *frame, uint32_t format,
		uint32_t width, uint32_t height, uint32_t stride) {
	struct dp_output *output = data;

	if (output->frame_buffer != NULL) {
		wl_buffer_destroy(output->frame_buffer);
	}

	output->frame_format = format;
	output->frame_stride = (int)stride;
	output->frame_buffer = dp_buffer_create(output->state, output->width, output->height,
			output->frame_stride, output->frame_format, &output->frame_data, &output->frame_size);
	zwlr_screencopy_frame_v1_copy(output->frame, output->frame_buffer);
}

static void frame_handle_flags(void *data, struct zwlr_screencopy_frame_v1 *frame, uint32_t flags) {
	struct dp_output *output = data;
	if ((flags & ZWLR_SCREENCOPY_FRAME_V1_FLAGS_Y_INVERT) != 0) {
		output->y_invert = true;
	}
}

static void frame_handle_ready(void *data, struct zwlr_screencopy_frame_v1 *frame,
		uint32_t tv_sec_hi, uint32_t tv_sec_lo, uint32_t tv_nsec) {
	struct dp_output *output = data;

	zwlr_screencopy_frame_v1_destroy(output->frame);
	output->frame = NULL;

	output->has_frame = true;

	wl_surface_commit(output->main_surface);
}

static void frame_handle_failed(void *data, struct zwlr_screencopy_frame_v1 *frame) {
	dp_log_fatal("Failed to copy a frame");
}

static const struct zwlr_screencopy_frame_v1_listener frame_listener = {
	.buffer = frame_handle_buffer,
	.flags = frame_handle_flags,
	.ready = frame_handle_ready,
	.failed = frame_handle_failed,
};

static void buffer_handle_release(void *data, struct wl_buffer *wl_buffer) {
	struct dp_buffer *buffer = data;
	buffer->used = false;
}

static const struct wl_buffer_listener buffer_listener = {
	.release = buffer_handle_release,
};

static void output_handle_geometry(void *data, struct wl_output *wl_output, int32_t x, int32_t y,
		int32_t phys_width, int32_t phys_height, int32_t subpixel, const char *make,
		const char *model, int32_t transform) {
	struct dp_output *output = data;

	if (output->has_geom) {
		if (transform != output->transform) {
			dp_log_fatal("Output transform has changed: %d (%#x) => %d (%#x)", output->transform,
					output->transform, transform, transform);
		}
	}

	output->transform = transform;
}

static void output_handle_mode(void *data, struct wl_output *wl_output, uint32_t flags,
		int32_t width, int32_t height, int32_t refresh) {
	struct dp_output *output = data;

	if (output->has_geom) {
		if (width != output->width || height != output->height) {
			dp_log_fatal("Output mode has changed: %dx%d => %dx%d", output->width, output->height,
					width, height);
		}
	}

	output->width = width;
	output->height = height;
}

static void output_handle_done(void *data, struct wl_output *wl_output) {
	struct dp_output *output = data;

	if (output->has_geom) {
		return;
	}

	if ((output->transform & WL_OUTPUT_TRANSFORM_90) != 0) {
		output->transformed_width = output->height;
		output->transformed_height = output->width;
	} else {
		output->transformed_width = output->width;
		output->transformed_height = output->height;
	}

	output->has_geom = true;

	struct dp_state *state = output->state;

	output->frame = zwlr_screencopy_manager_v1_capture_output(
			state->screencopy_manager, state->show_cursors, output->wl_output);
	zwlr_screencopy_frame_v1_add_listener(output->frame, &frame_listener, output);

	output->main_surface = wl_compositor_create_surface(state->compositor);
	output->main_layer_surface = zwlr_layer_shell_v1_get_layer_surface(state->layer_shell,
			output->main_surface, output->wl_output, ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY, "dulcepan");
	output->main_viewport = wp_viewporter_get_viewport(state->viewporter, output->main_surface);

	wl_surface_set_buffer_transform(output->main_surface, output->transform);

	struct wl_region *empty_region = wl_compositor_create_region(state->compositor);
	wl_surface_set_input_region(output->main_surface, empty_region);
	wl_region_destroy(empty_region);

	zwlr_layer_surface_v1_add_listener(output->main_layer_surface, &layer_surface_listener, output);

	zwlr_layer_surface_v1_set_anchor(output->main_layer_surface,
			ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP | ZWLR_LAYER_SURFACE_V1_ANCHOR_BOTTOM |
					ZWLR_LAYER_SURFACE_V1_ANCHOR_LEFT | ZWLR_LAYER_SURFACE_V1_ANCHOR_RIGHT);
	zwlr_layer_surface_v1_set_keyboard_interactivity(
			output->main_layer_surface, ZWLR_LAYER_SURFACE_V1_KEYBOARD_INTERACTIVITY_EXCLUSIVE);
	zwlr_layer_surface_v1_set_exclusive_zone(output->main_layer_surface, -1);

	output->select_surface = wl_compositor_create_surface(state->compositor);
	output->select_subsurface = wl_subcompositor_get_subsurface(
			state->subcompositor, output->select_surface, output->main_surface);
	output->select_viewport = wp_viewporter_get_viewport(state->viewporter, output->select_surface);
	wl_subsurface_set_desync(output->select_subsurface);

	wl_surface_set_user_data(output->select_surface, output);

	for (size_t i = 0; i < DP_SWAPCHAIN_LEN; i++) {
		struct dp_buffer *buffer = &output->swapchain[i];
		int stride = output->transformed_width * 4;
		buffer->wl_buffer =
				dp_buffer_create(state, output->transformed_width, output->transformed_height,
						stride, WL_SHM_FORMAT_ARGB8888, &buffer->data, &buffer->size);
		buffer->cairo_surface = cairo_image_surface_create_for_data(buffer->data,
				CAIRO_FORMAT_ARGB32, output->transformed_width, output->transformed_height, stride);
		buffer->cairo = cairo_create(buffer->cairo_surface);

		wl_buffer_add_listener(buffer->wl_buffer, &buffer_listener, buffer);
	}
}

static void output_handle_scale(void *data, struct wl_output *wl_output, int32_t scale) {
	// Ignored
}

static const struct wl_output_listener output_listener = {
	.geometry = output_handle_geometry,
	.mode = output_handle_mode,
	.done = output_handle_done,
	.scale = output_handle_scale,
};

static void redraw(struct dp_output *output);

static void redraw_callback_handle_done(
		void *data, struct wl_callback *callback, uint32_t callback_data) {
	struct dp_output *output = data;
	wl_callback_destroy(output->redraw_callback);
	output->redraw_callback = NULL;
	if (output->needs_redraw) {
		redraw(output);
	}
}

static const struct wl_callback_listener redraw_callback_listener = {
	.done = redraw_callback_handle_done,
};

static inline void set_cairo_color(cairo_t *cairo, float color[static 4]) {
	cairo_set_source_rgba(cairo, color[0], color[1], color[2], color[3]);
}

static void redraw(struct dp_output *output) {
	assert(output->redraw_callback == NULL);

	struct dp_buffer *buffer = NULL;
	for (size_t i = 0; i < DP_SWAPCHAIN_LEN; i++) {
		struct dp_buffer *iter = &output->swapchain[i];
		if (!iter->used) {
			buffer = iter;
			break;
		}
	}
	if (buffer == NULL) {
		dp_log_error("No free buffers in a swapchain\n");
		return;
	}
	buffer->used = true;

	struct dp_state *state = output->state;
	struct dp_config *config = &state->config;

	cairo_set_operator(buffer->cairo, CAIRO_OPERATOR_SOURCE);

	set_cairo_color(buffer->cairo, config->unselected_color);
	cairo_paint(buffer->cairo);

	struct dp_selection *selection = &state->selection;
	if (output == selection->output) {
		int border_size = config->border_size;
		if (border_size != 0) {
			cairo_set_line_width(buffer->cairo, border_size);
			double off = border_size / 2.0;
			cairo_rectangle(buffer->cairo, selection->x - off, selection->y - off,
					selection->width + border_size, selection->height + border_size);
			set_cairo_color(buffer->cairo, config->border_color);
			cairo_stroke(buffer->cairo);
		}

		cairo_rectangle(
				buffer->cairo, selection->x, selection->y, selection->width, selection->height);
		set_cairo_color(buffer->cairo, config->selected_color);
		cairo_fill(buffer->cairo);
	}

	wl_surface_attach(output->select_surface, buffer->wl_buffer, 0, 0);
	wl_surface_damage(
			output->select_surface, 0, 0, output->transformed_width, output->transformed_height);

	output->redraw_callback = wl_surface_frame(output->select_surface);
	wl_callback_add_listener(output->redraw_callback, &redraw_callback_listener, output);
	output->needs_redraw = false;

	wl_surface_commit(output->select_surface);
}

void dp_output_redraw(struct dp_output *output) {
	if (output->redraw_callback != NULL) {
		output->needs_redraw = true;
		return;
	}
	redraw(output);
}

void dp_output_hide_surface(struct dp_output *output) {
	wl_surface_attach(output->main_surface, NULL, 0, 0);
	wl_surface_commit(output->main_surface);
}

void dp_output_create(struct dp_state *state, uint32_t name, struct wl_output *wl_output) {
	struct dp_output *output = dp_zalloc(sizeof(*output));
	output->state = state;
	output->name = name;
	output->wl_output = wl_output;

	wl_output_add_listener(output->wl_output, &output_listener, output);

	wl_list_insert(&state->outputs, &output->link);
}

void dp_output_destroy(struct dp_output *output) {
	wl_output_release(output->wl_output);

	assert(output->frame == NULL);
	wl_buffer_destroy(output->frame_buffer);
	munmap(output->frame_data, output->frame_size);

	if (output->redraw_callback != NULL) {
		wl_callback_destroy(output->redraw_callback);
	}

	for (size_t i = 0; i < DP_SWAPCHAIN_LEN; i++) {
		struct dp_buffer *buffer = &output->swapchain[i];
		wl_buffer_destroy(buffer->wl_buffer);
		cairo_destroy(buffer->cairo);
		cairo_surface_destroy(buffer->cairo_surface);
		munmap(buffer->data, buffer->size);
	}

	wl_subsurface_destroy(output->select_subsurface);
	wp_viewport_destroy(output->select_viewport);
	wl_surface_destroy(output->select_surface);

	zwlr_layer_surface_v1_destroy(output->main_layer_surface);
	wp_viewport_destroy(output->main_viewport);
	wl_surface_destroy(output->main_surface);

	wl_list_remove(&output->link);
	free(output);
}