#include <uv.h>

#include "http.h"
#include "http_request.h"
#include "http_response.h"
#include "http_parser_settings.h"
#include "sandbox.h"

static http_parser_settings runtime_http_parser_settings;

/***********************************************************************
 * http-parser Callbacks in lifecycle order                            *
 **********************************************************************/

/**
 * http-parser data callback called when a URL is called
 * Sanity check to make sure that the path matches the name of the module
 * @param parser
 * @param at the start of the URL
 * @param length the length of the URL
 * @returns 0
 */
int
http_parser_settings_on_url(http_parser *parser, const char *at, size_t length)
{
	struct sandbox *sandbox = (struct sandbox *)parser->data;
	if (sandbox->http_request.message_end || sandbox->http_request.header_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
	assert(strncmp(sandbox->module->name, (at + 1), length - 1) == 0);
#endif

	return 0;
}

/**
 * http-parser callback called when parsing of a new message begins
 * Sets the HTTP Request's message_begin and last_was_value flags to true
 * @param parser
 */
int
http_parser_settings_on_message_begin(http_parser *parser)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;

	if (sandbox->http_request.message_end || sandbox->http_request.header_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	http_request->message_begin  = true;
	http_request->last_was_value = true; /* should always start with a header */
	sandbox->is_repeat_header    = false;
	return 0;
}

/**
 * http-parser callback called when a header field is parsed
 * Sets the key value of the latest header on a new header if last_was_value is true
 * updating an existing header if last_was_value is false
 * @param parser
 * @param at start address of the header field
 * @param length length of the header field
 * @returns 0
 */
int
http_parser_settings_on_header_field(http_parser *parser, const char *at, size_t length)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;

	if (sandbox->http_request.message_end || sandbox->http_request.header_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	/* Previous name continues */
	if (http_request->last_was_value == false) {
		assert(http_request->header_count > 0);
		strncat(http_request->headers[http_request->header_count].key, at, length);
		return 0;
	}

	/*
	 * We receive repeat headers for an unknown reason, so we need to ignore repeat headers
	 * This probably means that the headers are getting reparsed, so for the sake of performance
	 * this should be fixed upstream
	 */


#ifdef LOG_HTTP_PARSER
	for (int i = 0; i < http_request->header_count; i++) {
		if (strncmp(http_request->headers[i].key, at, length) == 0) {
			debuglog("Repeat header!\n");
			assert(0);
			sandbox->is_repeat_header = true;
			break;
		}
	}
#endif

	if (!sandbox->is_repeat_header) {
		if (unlikely(http_request->header_count >= HTTP_MAX_HEADER_COUNT)) { return -1; }
		if (unlikely(length > HTTP_MAX_HEADER_LENGTH)) { return -1; }
		http_request->headers[http_request->header_count++].key = (char *)at;
		http_request->last_was_value                            = false;
		sandbox->is_repeat_header                               = false;
	}

	return 0;
}

/**
 * http-parser callback called when a header value is parsed
 * Writes the value to the latest header and sets last_was_value to true
 * @param parser
 * @param at start address of the header value
 * @param length length of the header value
 * @returns 0
 */
int
http_parser_settings_on_header_value(http_parser *parser, const char *at, size_t length)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;

	if (http_request->message_end || http_request->header_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	// TODO: If last_was_value is already true, we might need to append to value


	/* it is from the sandbox's request_response_data, should persist. */
	if (!sandbox->is_repeat_header) {
		if (unlikely(length >= HTTP_MAX_HEADER_VALUE_LENGTH)) return -1;
		http_request->headers[http_request->header_count - 1].value = (char *)at;
		http_request->last_was_value                                = true;
	}
	return 0;
}

/**
 * http-parser callback called when header parsing is complete
 * Just sets the HTTP Request's header_end flag to true
 * @param parser
 */
int
http_parser_settings_on_header_end(http_parser *parser)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;
	if (http_request->message_end || http_request->header_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	http_request->header_end = true;
	return 0;
}

/**
 * http-parser callback called for HTTP Bodies
 * Assigns the parsed data to the http_request body of the sandbox struct
 * Presumably, this might only be part of the body
 * @param parser
 * @param at - start address of body
 * @param length - length of body
 * @returns 0
 */
int
http_parser_settings_on_body(http_parser *parser, const char *at, size_t length)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;

	if (http_request->message_end) return 0;

#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	/* Assumption: We should never exceed the buffer we're reusing */
	assert(http_request->body_length + length <= sandbox->module->max_request_size);


	if (!http_request->body) {
		/* If this is the first invocation of the callback, just set */
		http_request->body        = (char *)at;
		http_request->body_length = length;
	} else {
#ifdef LOG_HTTP_PARSER
		debuglog("Body: %p, Existing Length: %d\n", http_request->body, http_request->body_length);

		debuglog("Expected Offset %d, Actual Offset: %lu\n", http_request->body_length,
		         at - http_request->body);

		/* Attempt to copy and print the entire body */
		uint64_t possible_body_len = at - http_request->body;
		char     test_buffer[possible_body_len + length + 1];
		strncpy(test_buffer, http_request->body, possible_body_len);
		test_buffer[length] = '\0';
		debuglog("http_parser_settings_on_body: len %lu, content: %s\n", possible_body_len, test_buffer);
#endif

		http_request->body_length += length;
	}

	return 0;
}

/**
 * Sets the HTTP Request's message_end flag to true
 * @param parser
 * @returns 0
 */
int
http_parser_settings_on_msg_end(http_parser *parser)
{
	struct sandbox *     sandbox      = (struct sandbox *)parser->data;
	struct http_request *http_request = &sandbox->http_request;

	if (http_request->message_end) return 0;
#ifdef LOG_HTTP_PARSER
	debuglog("sandbox: %lu\n", sandbox->request_arrival_timestamp);
#endif

	http_request->message_end = true;
	return 0;
}

/***********************************************************************
 * http-parser Setup and Excute                                        *
 **********************************************************************/

/**
 * The settings global with the Callback Functions for HTTP Events
 */
static inline void
http_parser_settings_register_callbacks(http_parser_settings *settings)
{
	settings->on_url              = http_parser_settings_on_url;
	settings->on_message_begin    = http_parser_settings_on_message_begin;
	settings->on_header_field     = http_parser_settings_on_header_field;
	settings->on_header_value     = http_parser_settings_on_header_value;
	settings->on_headers_complete = http_parser_settings_on_header_end;
	settings->on_body             = http_parser_settings_on_body;
	settings->on_message_complete = http_parser_settings_on_msg_end;
}

/**
 * This is really the only function that should have to be called to setup this structure
 */
void
http_parser_settings_initialize()
{
	http_parser_settings_init(&runtime_http_parser_settings);
	http_parser_settings_register_callbacks(&runtime_http_parser_settings);
}

http_parser_settings *
http_parser_settings_get()
{
	return &runtime_http_parser_settings;
}