#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#include <string.h>
#include <regex.h>
#include "sds/sds.h"
#include "util.h"

struct md_syntax {
	regex_t anchor;
};

struct md_syntax syntax = {
	.anchor = NULL,
};

int* anchorsIndecies;
int anchorsCount = 0;

void initRendering() {
	/*
	 * Compile regexes used in rendering
	 */

	 herr(regcomp(&syntax.anchor, "\\[\\([^]]*\\)\\](\\([^)]*\\))", 0), "regcomp");
}

void freeRendering() {
	regfree(&syntax.anchor);

	free(anchorsIndecies);
}

void renderPage(const sds page) {
	if (sdslen(page) == 0) {
		printf("Server didn't return page!\n");
		return;
	}

	sds toPrint = sdsdup(page);
	
	/*
	 * Parse Markdown constructs
	 */

	/* Substitute and store anchorsIndecies */
	if (anchorsIndecies != NULL) {
		free(anchorsIndecies);
		anchorsCount = 0;
		anchorsIndecies = NULL;
	}
	toPrint = gsub_getm(toPrint, &syntax.anchor, "\16\033[4m\1\033[0m", &anchorsIndecies, &anchorsCount);
	
	sds newPrint;
	for (int i = 0, anchorInd = 0; i < anchorsCount; i++) {
		anchorInd = strchr(toPrint, '\16') - toPrint;

		/* In toPrint, replace '\16' with "\033[30;46m%d\033[0m", where %d is the variable i */
		toPrint[anchorInd] = '\0';
		newPrint = sdsgrowzero(sdsempty(), sdslen(toPrint) + digits(i) + 8 + 4);
		snprintf(newPrint, sdslen(newPrint), "%s\033[30;46m%d\033[0m%s", toPrint, i, toPrint + anchorInd + 1);

		sdsfree(toPrint);
		toPrint = newPrint;
	}

	/*
	 * Print page on stdout
	 */
	write(1, toPrint, sdslen(toPrint));

	sdsfree(toPrint);
}

#define MAX_LEN_COMMAND 16
#define COMMAND_FORMAT ": %16s"

int portLen(char* start) {
	int count = 0;
	while ('0' <= *start && *start <= '9') {
		count++;
		start++;
	}
	return count;
}

int hostLen(char* start) {
	int count = 0;
	while (*start == '.' || ('0' <= *start && *start <= '9')) {
		count++;
		start++;
	}
	return count;
}

char* findBeginningOfPath(char* uri) {
	char* startPath = strchr(uri, '/');
	while (startPath != uri && startPath != NULL) {
		if (*(startPath - 1) == '.') startPath--;
		else break;
	}
	return startPath;
}

int handleBrowserCLI(sds *host, sds *port, sds *uri, const sds page) {
	// Get a line
	char line[1024];
	fgets(line, 1024, stdin);

	// Nothing
	if (line[0] == '\0') {
		printf("Please enter a valid command!\n");
		return 0;
	}

	// Number or URL
	if (line[0] != ':') {
		sds newURI;

		// Index of anchor
		if (isNumber(line)) {
			int gotoIndex = 0;
			sscanf(line, "%d", &gotoIndex);

			if (gotoIndex < 0 || gotoIndex >= anchorsCount) {
				printf("Invalid anchor index!\n");
				return 0;
			}

			char* start = strchr(page + anchorsIndecies[gotoIndex], '(') + 1;
			newURI = sdsnewlen(start, strchr(start, ')') - start);
		}
		// New address
		else {
			newURI = sdsnewlen(line, strlen(line)-1); // skip newline
		}

		char* startPath = findBeginningOfPath(newURI);

		// Handle relative URLs
		if (startPath == newURI) {
			sds beforePath = sdscatsds(sdsnewlen(*uri, findBeginningOfPath(*uri) - *uri), newURI);
			sdsfree(newURI);
			newURI = beforePath;
			startPath = findBeginningOfPath(newURI);
		}

		if (*uri != NULL) sdsfree(*uri);
		*uri = newURI;

		char* startHost = strchr(newURI, '@');
		char* startPort = strchr(newURI, ':');

		// Update host
		if (startHost != NULL && startHost < startPath) {
			if (host != NULL) sdsfree(*host);
			*host = sdsnewlen(startHost + 1, hostLen(startHost + 1));
		}

		// Update port
		if (startPort != NULL && startPort < startPath) {
			if (port != NULL) sdsfree(*port);
			*port = sdsnewlen(startPort + 1, portLen(startPort + 1));
		}

		return 0;
	}

	// Special command
	
	// Get command name and it's arguments
	// Currently no command takes arguments
	char name[MAX_LEN_COMMAND+1] = { '\0' };
	sscanf(line, COMMAND_FORMAT, name); // Flawfinder: ignore

	if (streq(name, "q") || streq(name, "e") || streq(name, "quit") || streq(name, "exit")) {
		return 1;
	}

	printf("Invalid command %s!\n", name);
	return 0;
}