#include "app.h"
#include "reactor/pool.h"
#include "reactor/epoll.h"

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <fcntl.h>

#define DEFAULT_MAX_CONNS 10000
#define DEFAULT_MAX_EVENTS 4096

// Default 404 handler
static void default_not_found(context_t *ctx) {
	// send_text(ctx, 404, "404 Not Found");
}

// Accept handler for new connections
static void accept_handler(runtime_t *rt, int fd, uint32_t events, void *data) {
	app_t *a = (app_t*)data;

	// Accept multiple connections in a loop for edge-triggered mode
	// Limit to prevent starvation of other events
	int accepted = 0;
	const int max_accept = 64;
	
	while (accepted < max_accept) {
		int ret = conn_accept(a->pool, fd);
		if (ret < 0) break;
		accepted++;
	}
}

// Global app pointer (temporary solution)
static app_t *g_app = NULL;

// Wrapper to convert between handler types
static void handler_wrapper(conn_t *c) {
	app_handler_t app_handler = (app_handler_t)c->user_data;
	if (app_handler) {
		context_t *ctx = context_new(c);
		if (ctx) {
			app_handler(ctx);
			context_free(ctx);
		}
	}
}

// Request router
static void route_request(conn_t *c) {
	app_t *a = g_app;  // Use global for now
	if (!a || !a->router) return;
	
	// Use the router to find handler
	char **params = NULL;
	char **names = NULL;
	int count = 0;
	handler_t handler = router_lookup(a->router, c->method, c->path, &params, &names, &count);
	
	if (handler) {
		// The handler is actually an app_handler_t cast to handler_t
		// Create context and call it
		context_t *ctx = context_new(c);
		if (ctx) {
			// Store params in context (we'd need to add this to context)
			// For now, just call the handler
			((app_handler_t)handler)(ctx);
			context_free(ctx);
		}
	} else {
		// Create a context and call not_found
		context_t *ctx = context_new(c);
		if (ctx) {
			a->not_found(ctx);
			context_free(ctx);
		}
	}
}

// app_new creates a new web application.
app_t* app_new(void) {
	app_t *a = calloc(1, sizeof(app_t));
	if (!a) return NULL;

	// Default configuration
	a->max_conns = DEFAULT_MAX_CONNS;
	a->read_buf_size = 8192;
	a->write_buf_size = 8192;
	a->arena_size = 4096;
	a->not_found = default_not_found;
	
	// Create router
	a->router = router_new();
	if (!a->router) {
		free(a);
		return NULL;
	}
	
	// Store global reference (temporary solution)
	g_app = a;

	return a;
}

// app_free destroys the application.
void app_free(app_t *a) {
	if (!a) return;

	// Free router
	if (a->router) {
		router_free(a->router);
	}

	// Close listener
	if (a->listen_fd > 0) {
		runtime_del(a->rt, a->listen_fd);
		close(a->listen_fd);
	}

	// Free pool and runtime
	pool_free(a->pool);
	runtime_free(a->rt);
	free(a);
}

// app_listen sets up the listening socket.
int app_listen(app_t *a, int port) {
	// Create runtime and pool if not already done
	if (!a->rt) {
		a->rt = runtime_new(DEFAULT_MAX_EVENTS);
		if (!a->rt) return -1;
	}

	if (!a->pool) {
		a->pool = pool_new(a->rt, a->max_conns);
		if (!a->pool) return -1;

		// Configure pool
		a->pool->read_buf_size = a->read_buf_size;
		a->pool->write_buf_size = a->write_buf_size;
		a->pool->arena_size = a->arena_size;

		// Set router as request handler
		a->pool->on_request = route_request;
	}

	// Create socket
	int fd = socket(AF_INET, SOCK_STREAM, 0);
	if (fd < 0) return -1;

	// Allow reuse
	int opt = 1;
	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
	
	// Enable SO_REUSEPORT for better load distribution across CPU cores
	setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
	
	// Disable Nagle's algorithm on listener
	setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));

	// Bind
	struct sockaddr_in addr = {
		.sin_family = AF_INET,
		.sin_port = htons(port),
		.sin_addr.s_addr = INADDR_ANY
	};

	if (bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
		close(fd);
		return -1;
	}

	// Listen with larger backlog for better performance
	if (listen(fd, 4096) < 0) {
		close(fd);
		return -1;
	}

	// Make non-blocking
	set_nonblocking(fd);

	// Add to epoll
	runtime_add(a->rt, fd, EPOLLIN | EPOLLET, accept_handler, a);

	a->listen_fd = fd;
	a->port = port;

	printf("Server listening on :%d\n", port);
	return 0;
}

// app_run starts the event loop.
int app_run(app_t *a) {
	if (!a->rt || a->listen_fd <= 0) {
		return -1;
	}

	// Override pool callback with router
	a->pool->on_request = route_request;

	return runtime_run(a->rt);
}

// app_route registers a route.
void app_route(app_t *a, const char *method, const char *path, app_handler_t handler) {
	if (!a || !a->router) return;
	
	// For now, we need to bridge between app_handler_t and handler_t
	// The router expects handler_t (conn_t*) but we have app_handler_t (context_t*)
	// We'll need to wrap it somehow - for now just cast (not ideal)
	router_add(a->router, method, path, (handler_t)handler);
}

// Convenience route methods
void app_get(app_t *a, const char *path, app_handler_t handler) {
	app_route(a, "GET", path, handler);
}

void app_post(app_t *a, const char *path, app_handler_t handler) {
	app_route(a, "POST", path, handler);
}

void app_put(app_t *a, const char *path, app_handler_t handler) {
	app_route(a, "PUT", path, handler);
}

void app_delete(app_t *a, const char *path, app_handler_t handler) {
	app_route(a, "DELETE", path, handler);
}

// Configuration setters
void app_set_max_conns(app_t *a, int max) {
	a->max_conns = max;
}

void app_set_buffer_sizes(app_t *a, size_t read_size, size_t write_size) {
	a->read_buf_size = read_size;
	a->write_buf_size = write_size;
}

void app_set_arena_size(app_t *a, size_t size) {
	a->arena_size = size;
}

void app_set_not_found(app_t *a, app_handler_t handler) {
	a->not_found = handler;
}

// Helper response functions
static void send_text(conn_t *c, int status, const char *text) {
	conn_write_status(c, status);
	conn_write_header(c, "Content-Type", "text/plain");
	conn_write_body(c, text, strlen(text));
}

void send_json(conn_t *c, int status, const char *json) {
	conn_write_status(c, status);
	conn_write_header(c, "Content-Type", "application/json");
	conn_write_body(c, json, strlen(json));
}

void send_html(conn_t *c, int status, const char *html) {
	conn_write_status(c, status);
	conn_write_header(c, "Content-Type", "text/html");
	conn_write_body(c, html, strlen(html));
}

void send_file(conn_t *c, const char *path) {
	// Simple file serving (no caching, no range support)
	FILE *f = fopen(path, "rb");
	if (!f) {
		send_text(c, 404, "File not found");
		return;
	}

	// Get file size
	fseek(f, 0, SEEK_END);
	size_t size = ftell(f);
	fseek(f, 0, SEEK_SET);

	// Determine content type from extension
	const char *content_type = "application/octet-stream";
	const char *ext = strrchr(path, '.');
	if (ext) {
		if (strcmp(ext, ".html") == 0) content_type = "text/html";
		else if (strcmp(ext, ".css") == 0) content_type = "text/css";
		else if (strcmp(ext, ".js") == 0) content_type = "application/javascript";
		else if (strcmp(ext, ".json") == 0) content_type = "application/json";
		else if (strcmp(ext, ".png") == 0) content_type = "image/png";
		else if (strcmp(ext, ".jpg") == 0 || strcmp(ext, ".jpeg") == 0) content_type = "image/jpeg";
		else if (strcmp(ext, ".gif") == 0) content_type = "image/gif";
		else if (strcmp(ext, ".svg") == 0) content_type = "image/svg+xml";
	}

	// Send headers
	conn_write_status(c, 200);
	conn_write_header(c, "Content-Type", content_type);

	// For small files, read and send directly
	if (size < c->wsize - c->wlen - 100) {
		char *buf = malloc(size);
		if (buf) {
			fread(buf, 1, size, f);
			conn_write_body(c, buf, size);
			free(buf);
		}
	} else {
		// File too large for buffer
		conn_write_status(c, 500);
		conn_end_response(c);
	}

	fclose(f);
}