#include <ctype.h>

#include <kore/kore.h>
#include <kore/http.h>
#include <kore/pgsql.h>
#include <kore/seccomp.h>

#include "../lib/md4c/src/entity.h"
#include "../lib/md4c/src/entity.c"
#include "../lib/md4c/src/md4c.h"
#include "../lib/md4c/src/md4c.c"
#include "../lib/md4c/src/md4c-html.h"
#include "../lib/md4c/src/md4c-html.c"

#include "assets.h"
#include "queries.h"  // FIXME: Compilation fail if this is a .c file.

KORE_SECCOMP_FILTER("clog",
    KORE_SYSCALL_ALLOW(bind),
    KORE_SYSCALL_ALLOW(getdents64),
    KORE_SYSCALL_ALLOW(newfstatat),
    KORE_SYSCALL_ALLOW(sendmmsg),
    KORE_SYSCALL_ALLOW(uname)
)

enum query_status { QUERY_STATUS_OK, QUERY_STATUS_ERROR, QUERY_STATUS_NOT_FOUND };

struct entry_query {
	char *id;

	int status;
	struct kore_buf *result;
};

static const char *database = "db";

static const char * const error_msg[] = {
	[HTTP_STATUS_OK] = "OK",                                                        // 200
	[HTTP_STATUS_CREATED] = "Resource created successfully.",                       // 201
	[HTTP_STATUS_BAD_REQUEST] = "There was an error processing the request data.",  // 400
	[HTTP_STATUS_NOT_FOUND] = "Resource not found.",                                // 404
	[HTTP_STATUS_INTERNAL_ERROR] = "There was an error processing the request.",    // 500
};

void entry_query_init(struct entry_query *eq, const char *id);
void entry_query_cleanup(struct entry_query *eq);

int validate_uuid(const char *uuid);

int http_ok_resp(struct http_request *req, enum http_status_code status, struct kore_buf *result);

int http_err_resp(
	struct http_request *req,
	enum http_status_code status
);

int redirect(struct http_request *req);

int get_entries(struct http_request *req);
int get_entry(struct http_request *req);
int post_entry(struct http_request *req);
int put_entry(struct http_request *req);
int delete_entry(struct http_request *req);

int v_example_func(struct http_request *req, char *data);

int get_entry_form(struct http_request *req);
int post_entry_form(struct http_request *req);

int sql_select_entries(struct entry_query *eq);
int sql_update_entry(const char *id, const char *title, const char *body);
int sql_delete_entry(const char *id);
int sql_insert_entry(const char *id, const char *title, const char *body);

int sql_render_entry(struct kore_pgsql *sql, struct entry_query *eq);
int sql_render_index(struct kore_pgsql *sql, struct entry_query *eq);

static void process_md_output(const MD_CHAR *html, MD_SIZE size, void *buf);
static int render_md(const char *in, struct kore_buf *out);

void entry_query_init(struct entry_query *eq, const char *id) {
	if (id != NULL)
		eq->id = kore_strdup(id);
	else
		eq->id = NULL;

	eq->status = QUERY_STATUS_OK;
	eq->result = kore_buf_alloc(0);
}

void entry_query_cleanup(struct entry_query *eq) {
	if (eq->id != NULL)
		kore_free((void *) eq->id);
	eq->id = NULL;
	
	if (eq->result != NULL)
		kore_buf_free(eq->result);
	eq->result = NULL;
}

int validate_uuid(const char *uuid) {
	int i = 0;

	if (strlen(uuid) != 36)
		return KORE_RESULT_ERROR;

	for (i = 0; i <= 36; i++) {
		if ((i == 8) || (i == 13) || (i == 18) || (i == 23)) {
			if (uuid[i] != '-')
				return KORE_RESULT_ERROR;
			continue;
		}
		if (i == 36) {
			if (uuid[i] != '\0')
				return KORE_RESULT_ERROR;
			continue;
		}
		if (!isxdigit(uuid[i]))
			return KORE_RESULT_ERROR;
	}

	return KORE_RESULT_OK;
}

int http_ok_resp(
	struct http_request *req,
	enum http_status_code status,
	struct kore_buf *result
) {
	struct kore_buf *resp_buf = kore_buf_alloc(0);
	const char *body = kore_buf_stringify(result, NULL);

	http_response_header(req, "content-type", "text/html; charset=utf-8");
	kore_buf_append(resp_buf, asset_index_begin_html, asset_len_index_begin_html);
	kore_buf_append(resp_buf, body, strlen(body));
	kore_buf_append(resp_buf, asset_index_end_html, asset_len_index_end_html);

	http_response(req, status, resp_buf->data, resp_buf->offset);

	kore_buf_free(resp_buf);

	return KORE_RESULT_OK;
}

int http_err_resp(
	struct http_request *req,
	enum http_status_code status
) {
	struct kore_buf *resp_buf = kore_buf_alloc(0);

	http_response_header(req, "content-type", "text/html; charset=utf-8");
	kore_buf_append(resp_buf, asset_index_begin_html, asset_len_index_begin_html);
	kore_buf_appendf(resp_buf, (const char *) asset_error_html, error_msg[status]);
	kore_buf_append(resp_buf, asset_index_end_html, asset_len_index_end_html);

	http_response(req, status, resp_buf->data, resp_buf->offset);

	kore_buf_free(resp_buf);

	return KORE_RESULT_OK;
}

int redirect(struct http_request *req) {
	http_response_header(req, "Location", "/");
	http_response(req, HTTP_STATUS_TEMPORARY_REDIRECT, NULL, 0);
	return KORE_RESULT_OK;
}

int v_example_func(struct http_request *req, char *data) {
	kore_log(LOG_NOTICE, "v_example_func called");
	return KORE_RESULT_OK;
}

int get_entry_form(struct http_request *req) {
	struct kore_buf *resp_buf = kore_buf_alloc(0);

	kore_buf_appendf(resp_buf, (const char *) asset_entry_edit_html, "", "", "");
	http_ok_resp(req, HTTP_STATUS_OK, resp_buf);

	kore_buf_free(resp_buf);

	return KORE_RESULT_OK;
}


int post_entry_form(struct http_request *req) {
	struct kore_buf *resp_buf = kore_buf_alloc(0);

	char *id = NULL;
	char *title = NULL; 
	char *body = NULL;

	http_populate_post(req);

	if (http_argument_get_string(req, "id", &id)) {
		kore_log(LOG_INFO, "form id %s.", id);
	}

	if (http_argument_get_string(req, "title", &title)) {
		kore_log(LOG_INFO, "form title %s.", title);
	}
	
	if (http_argument_get_string(req, "body", &body)) {
		kore_log(LOG_INFO, "form body %s.", body);
	}

	// Append form.
	kore_buf_appendf(
		resp_buf, (const char *) asset_entry_edit_html,
		id ? id : "", title ? title: "", body ? body : ""
	);

	// Render MD.
	(void) render_md(body, resp_buf);
	// if (err == KORE_RESULT_ERROR) {
	// 	kore_log(LOG_ERR, "Error rendering markdown for entry %s.", id);
	// 	continue;
	// }

	http_ok_resp(req, HTTP_STATUS_OK, resp_buf);

	kore_buf_free(resp_buf);

	return KORE_RESULT_OK;
}


int get_entries(struct http_request *req) {
	struct entry_query eq;

	entry_query_init(&eq, NULL);

	(void) sql_select_entries(&eq);
	if (eq.status != QUERY_STATUS_OK)
		http_err_resp(req, HTTP_STATUS_INTERNAL_ERROR);
	else
		http_ok_resp(req, HTTP_STATUS_OK, eq.result);

	entry_query_cleanup(&eq);

	return KORE_RESULT_OK;
}

int get_entry(struct http_request *req) {
	int err = 0;

	struct entry_query eq;

	entry_query_init(&eq, req->path + strlen("/entries/"));

	// Check for valid resource UUID
	kore_log(LOG_DEBUG, "Resource id /entries/%s.", eq.id);
	err = validate_uuid(eq.id);
	if (err == KORE_RESULT_ERROR) {
		kore_log(LOG_ERR, "Invalid entry id %s.", eq.id);
		http_err_resp(req, HTTP_STATUS_NOT_FOUND);
		goto out;
	}

	(void) sql_select_entries(&eq);
	if (eq.status == QUERY_STATUS_NOT_FOUND)
		http_err_resp(req, HTTP_STATUS_NOT_FOUND);
	else if (eq.status == QUERY_STATUS_ERROR)
		http_err_resp(req, HTTP_STATUS_INTERNAL_ERROR);
	else
		http_ok_resp(req, HTTP_STATUS_OK, eq.result);

out: ;

	entry_query_cleanup(&eq);

	return KORE_RESULT_OK;
}

int post_entry(struct http_request *req) {
	int err = 0;

	int status = HTTP_STATUS_CREATED;

	const char *id = NULL;
	const char *title = NULL;
	const char *body = NULL;

	struct kore_json_item *item = NULL;
	struct kore_json json;

	kore_json_init(&json, req->http_body->data, req->http_body->length);

	if (!kore_json_parse(&json)) {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "error parsing json: %s\n", kore_json_strerror());
		goto out;
	}

	item = kore_json_find_string(json.root, "id");
	if (item != NULL) {
		id = item->data.string;
		kore_log(LOG_INFO, "id = '%s'\n", id);
		// Check for valid resource ID/UUID
		err = validate_uuid(id);
		if (err == KORE_RESULT_ERROR) {
			status = HTTP_STATUS_BAD_REQUEST;
			kore_log(LOG_ERR, "Invalid entry UUID %s.", id);
			goto out;
		}
	}

	item = kore_json_find_string(json.root, "title");
	if (item != NULL) {
		title = item->data.string;
		kore_log(LOG_INFO, "title = '%s'\n", title);
	} else {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "error parsing title: %s\n", kore_json_strerror());
		goto out;
	}

	item = kore_json_find_string(json.root, "body");
	if (item != NULL) {
		body = item->data.string;
		kore_log(LOG_INFO, "body = '%s'\n", body);
	} else {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "error parsing body: %s\n", kore_json_strerror());
		goto out;
	}

	err = sql_insert_entry(id, title, body);

	if (err == KORE_RESULT_ERROR) {
		status = HTTP_STATUS_INTERNAL_ERROR;
		goto out;
	}

out: ;

	http_err_resp(req, status);

	kore_json_cleanup(&json);

	return KORE_RESULT_OK;
}

int put_entry(struct http_request *req) {
	int err = 0;

	int status = HTTP_STATUS_OK;

	const char *id = NULL;
	const char *title = NULL;
	const char *body = NULL;

	struct kore_json_item *item = NULL;
	struct kore_json json;

	kore_json_init(&json, req->http_body->data, req->http_body->length);

	id = req->path + strlen("/entries/");

	// Check for valid resource UUID
	kore_log(LOG_DEBUG, "Resource id /entries/%s.", id);
	err = validate_uuid(id);
	if (err == KORE_RESULT_ERROR) {
		kore_log(LOG_ERR, "Invalid entry id %s.", id);
		http_err_resp(req, HTTP_STATUS_NOT_FOUND);
		goto out;
	}

	if (!kore_json_parse(&json)) {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "error parsing json: %s\n", kore_json_strerror());
		goto out;
	}

	item = kore_json_find_string(json.root, "title");
	if (item != NULL) {
		title = item->data.string;
		kore_log(LOG_INFO, "title = '%s'\n", title);
	} else {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "Error parsing title: %s\n", kore_json_strerror());
		goto out;
	}

	item = kore_json_find_string(json.root, "body");
	if (item != NULL) {
		body = item->data.string;
		kore_log(LOG_INFO, "body = '%s'\n", body);
	} else {
		status = HTTP_STATUS_BAD_REQUEST;
		kore_log(LOG_ERR, "Error parsing body: %s\n", kore_json_strerror());
		goto out;
	}

	err = sql_update_entry(id, title, body);

	if (err == KORE_RESULT_ERROR) {
		status = HTTP_STATUS_INTERNAL_ERROR;
		goto out;
	}

out: ;

	http_err_resp(req, status);

	kore_json_cleanup(&json);

	return KORE_RESULT_OK;
}

int sql_select_entries(struct entry_query *eq) {
	int err = KORE_RESULT_OK;

	struct kore_pgsql sql;

	kore_pgsql_init(&sql);

	eq->status = QUERY_STATUS_OK;

	// Set up synchronous database handle.
	err = kore_pgsql_setup(&sql, database, KORE_PGSQL_SYNC);
	if (err == KORE_RESULT_ERROR) {
		eq->status = QUERY_STATUS_ERROR;
		kore_pgsql_logerror(&sql);
		goto out;
	}

	// Query for entries, check for error.
	if (eq->id != NULL) {
		// Query an entry.
		err = kore_pgsql_query_params(
			&sql,
			q_select_entry,
			0,  // return string data
			1,  // param count
			KORE_PGSQL_PARAM_TEXT(eq->id)
		);
	} else {
		// Query for index.
		err = kore_pgsql_query(
			&sql,
			q_select_index
		);
	}

	if (err == KORE_RESULT_ERROR) {
		eq->status = QUERY_STATUS_ERROR;
		kore_pgsql_logerror(&sql);
		goto out;
	}

	// TODO: Add test for this; When database is empty, don't return 404 for base request.
	if (eq->id != NULL && kore_pgsql_ntuples(&sql) == 0) {
		eq->status = QUERY_STATUS_NOT_FOUND;
		goto out;
	}

	if (eq->id) {
		(void) sql_render_entry(&sql, eq);
	} else {
		(void) sql_render_index(&sql, eq);
	}

out: ;

	kore_pgsql_cleanup(&sql);

	return err;
}

int delete_entry(struct http_request *req) {
	int err = 0;

	const char *id = req->path + strlen("/entries/");

	// Check for valid resource UUID
	kore_log(LOG_DEBUG, "Resource id /entries/%s.", id);
	err = validate_uuid(id);
	if (err == KORE_RESULT_ERROR) {
		kore_log(LOG_ERR, "Invalid entry id %s.", id);
		http_err_resp(req, HTTP_STATUS_NOT_FOUND);
		goto out;
	}

	err = sql_delete_entry(id);
	// FIXME: should 404 if id doesn't exist.
	// if (eq.status == QUERY_STATUS_NOT_FOUND)
	// 	http_err_resp(req, HTTP_STATUS_NOT_FOUND);
	if (err == KORE_RESULT_ERROR)
		http_err_resp(req, HTTP_STATUS_INTERNAL_ERROR);
	else
		// TODO: test this; the test should explode.
		http_err_resp(req, HTTP_STATUS_OK);

out: ;

	return KORE_RESULT_OK;
}

int sql_render_entry(struct kore_pgsql *sql, struct entry_query *eq) {
	int err = KORE_RESULT_OK;

	int row = 0, rows = 0;

	struct kore_buf *html_buf = NULL;

	const char *id = NULL;
	const char *title = NULL;
	const char *created_at = NULL;
	const char *body = NULL;

	// Allocate a buffer to render the markdown as HTML into.
	html_buf = kore_buf_alloc(0);

	// Iterate over entries and render them.
	rows = kore_pgsql_ntuples(sql);
	for (row = 0; row < rows; row++) {
		// Reset buffer.
		kore_buf_cleanup(html_buf);

		// Fetch data.
		id = kore_pgsql_getvalue(sql, row, 0);
		title = kore_pgsql_getvalue(sql, row, 1);
		created_at = kore_pgsql_getvalue(sql, row, 2);
		body = kore_pgsql_getvalue(sql, row, 3);
		kore_log(LOG_DEBUG, "id: %s; title %s; created_at %s", id, title, created_at);

		// Render MD.
		err = render_md(body, html_buf);
		if (err == KORE_RESULT_ERROR) {
			kore_log(LOG_ERR, "Error rendering markdown for entry %s.", id);
			continue;
		}

		// Append rendered MD entry.
		kore_buf_appendf(
			eq->result,
			(const char *) asset_entry_html,
			kore_buf_stringify(html_buf, NULL)
		);

	}

	kore_buf_free(html_buf);

	return KORE_RESULT_OK;
}


int sql_render_index(struct kore_pgsql *sql, struct entry_query *eq) {

	int row = 0, rows = 0;

	struct kore_buf *html_buf = NULL;

	const char *id = NULL;
	const char *title = NULL;
	const char *created_at = NULL;
	const char *updated_at = NULL;

	// Allocate a buffer to render the markdown as HTML into.
	html_buf = kore_buf_alloc(0);

	// Write table header.
	kore_buf_append(
		eq->result,
		(const char *) "<h1>clog.bunkergate.org</h1>\r\n<table><tr><th>Title</th><th>Created</th><th>Updated</th></tr>\r\n",
		94
	);

	// Iterate over entries and render them.
	rows = kore_pgsql_ntuples(sql);
	for (row = 0; row < rows; row++) {
		// Reset buffer.
		kore_buf_cleanup(html_buf);

		// Fetch data.
		id = kore_pgsql_getvalue(sql, row, 0);
		title = kore_pgsql_getvalue(sql, row, 1);
		created_at = kore_pgsql_getvalue(sql, row, 2);
		updated_at = kore_pgsql_getvalue(sql, row, 3);
		kore_log(LOG_DEBUG, "id: '%s'; title '%s'", id, title);

		// Append rendered MD entry.
		kore_buf_appendf(
			eq->result,
			(const char *) "<tr><td><a href=\"/entries/%s\">%s</a></td><td>%s</td><td>%s</td></tr>\r\n",
			id,
			title,
			created_at,
			updated_at
		);

	}

	// Write table footer.
	kore_buf_append(
		eq->result,
		(const char *) "</table>\r\n",
		10
	);

	kore_buf_free(html_buf);

	return KORE_RESULT_OK;
}

int sql_insert_entry(const char *id, const char *title, const char *body) {
	int err = KORE_RESULT_OK;

	struct kore_pgsql sql;
	kore_pgsql_init(&sql);

	err = kore_pgsql_setup(&sql, database, KORE_PGSQL_SYNC);
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

	if (id == NULL) {
		err = kore_pgsql_query_params(
			&sql,
			q_insert_entry,
			0,
			2,
			KORE_PGSQL_PARAM_TEXT(title),
			KORE_PGSQL_PARAM_TEXT(body)
		);
	} else {
		err = kore_pgsql_query_params(
			&sql,
			q_insert_entry_with_id,
			0,
			3,
			KORE_PGSQL_PARAM_TEXT(id),
			KORE_PGSQL_PARAM_TEXT(title),
			KORE_PGSQL_PARAM_TEXT(body)
		);
	}
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

out: ;

	kore_pgsql_cleanup(&sql);

	return err;
}

int sql_update_entry(const char *id, const char *title, const char *body) {
	int err = KORE_RESULT_OK;

	struct kore_pgsql sql;
	kore_pgsql_init(&sql);

	err = kore_pgsql_setup(&sql, database, KORE_PGSQL_SYNC);
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

	err = kore_pgsql_query_params(
		&sql,
		q_update_entry,
		0,
		3,
		KORE_PGSQL_PARAM_TEXT(title),
		KORE_PGSQL_PARAM_TEXT(body),
		KORE_PGSQL_PARAM_TEXT(id)
	);
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

out: ;

	kore_pgsql_cleanup(&sql);

	return err;
}

int sql_delete_entry(const char *id) {
	int err = KORE_RESULT_OK;

	struct kore_pgsql sql;
	kore_pgsql_init(&sql);

	err = kore_pgsql_setup(&sql, database, KORE_PGSQL_SYNC);
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

	err = kore_pgsql_query_params(
		&sql,
		q_delete_entry,
		0,
		1,
		KORE_PGSQL_PARAM_TEXT(id)
	);
	if (err == KORE_RESULT_ERROR) {
		kore_pgsql_logerror(&sql);
		goto out;
	}

out: ;

	kore_pgsql_cleanup(&sql);

	return err;
}

static int render_md(const char *in, struct kore_buf *out) {
	// Not a kore err.
	int err = 0;

	static unsigned parser_flags = 0;
	static unsigned renderer_flags = 0;
	
	parser_flags |= MD_FLAG_TABLES;
	parser_flags |= MD_FLAG_STRIKETHROUGH;
	// render_flags |= MD_HTML_FLAG_DEBUG;

	err = md_html(in, (MD_SIZE) strlen(in), process_md_output, (void*) out, parser_flags, renderer_flags);

	if(err != 0) {
		kore_log(LOG_ERR, "Parsing Markdown failed.");
		return KORE_RESULT_ERROR;
	}

	return KORE_RESULT_OK;
}

static void process_md_output(const MD_CHAR *html, MD_SIZE size, void *buf) {
	kore_buf_append((struct kore_buf *) buf, (const void *) html, (size_t) size);
}