/*
 * ngx_http_hello_dolly.c
 */

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

static char *ngx_http_hello_dolly(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);

/* commands made available in the location config */
static ngx_command_t ngx_http_hello_dolly_commands[] = {
	{
		ngx_string("hello_dolly"),			// the directive
		NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,	// lives in a location block, and doesn't take any args
		ngx_http_hello_dolly,				// function callback
		0,									// setup
		0,									// offset
		NULL,								//post-processing
	},

	ngx_null_command
};

/* hello dolly contents */
static char *ngx_hello_dolly_strings[] = {
	"Hello, Dolly",
	"It's so nice to have you back where you belong",
	"You're lookin' swell, Dolly",
	"I can tell, Dolly"
};

/* we don't need to define any config handlers */
static ngx_http_module_t ngx_http_hello_dolly_module_ctx = {
	NULL,
	NULL,

	NULL,
	NULL,

	NULL,
	NULL,

	NULL,
	NULL
};

/* expose the module to nginx */
ngx_module_t ngx_http_hello_dolly_module = {
	NGX_MODULE_V1,
	&ngx_http_hello_dolly_module_ctx,	// module context
	ngx_http_hello_dolly_commands,		// module commands
	NGX_HTTP_MODULE,					// module type
	NULL,								// more handlers
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	NGX_MODULE_V1_PADDING				// lol no idea what the hell this is
};

/* this is where the magic happens */
static ngx_int_t ngx_http_hello_dolly_handler(ngx_http_request_t *r) {
	ngx_int_t rc;
	ngx_buf_t *b;
	ngx_chain_t out;

	// get a random item from the array. yes i know this is a bad way to do it.
	u_char *hello_dolly_str = (u_char *) ngx_hello_dolly_strings[0];

	// respond to GET and HEAD requests only
	if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) {
		return NGX_HTTP_NOT_ALLOWED;
	}

	// discard the request body
	rc = ngx_http_discard_request_body(r);
	if (rc != NGX_OK) {
		return rc;
	}

	// set the Content-Type, Content-Length, and Status headers
	r->headers_out.content_type_len = sizeof("text/plain") - 1;
	r->headers_out.content_type.len = sizeof("text/plain") - 1;
	r->headers_out.content_type.data = (u_char *) "text/plain";

	r->headers_out.content_length_n = sizeof(hello_dolly_str) - 1;
	r->headers_out.status = NGX_HTTP_OK;
	
	// if this is a HEAD request, just send the header
	if (r->method == NGX_HTTP_HEAD) {
		return ngx_http_send_header(r);
	}

	// allocate a buffer for the response body
	b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
	if (b == NULL) {
		return NGX_HTTP_INTERNAL_SERVER_ERROR;
	}

	// attach our buffer to the buffer chain
	out.buf = b;
	out.next = NULL;

	// adjust the buffer pointers
	b->pos = hello_dolly_str;
	b->last = hello_dolly_str + sizeof(hello_dolly_str) - 1;
	b->memory = 1;		// this buffer is in memory
	b->last_buf = 1;	// this is the last buffer in the buffer chain

	rc = ngx_http_send_header(r);

	if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
		return rc;
	}

	return ngx_http_output_filter(r, &out);
}

static char *ngx_http_hello_dolly(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) {
	ngx_http_core_loc_conf_t *clcf;

	clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
	clcf->handler = ngx_http_hello_dolly_handler;

	return NGX_CONF_OK;
}