/*
Some flash handling cgi routines. Used for reading the existing flash and updating the ESPFS image.
*/

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * Jeroen Domburg <jeroen@spritesmods.com> wrote this file. As long as you retain
 * this notice you can do whatever you want with this stuff. If we meet some day,
 * and you think this stuff is worth it, you can buy me a beer in return.
 * ----------------------------------------------------------------------------
 * Heavily modified and enhanced by Thorsten von Eicken in 2015
 * ----------------------------------------------------------------------------
 */


#include <esp8266.h>
#include <osapi.h>
#include "cgiflash.h"
#include "espfs.h"

// Check that the header of the firmware blob looks like actual firmware...
static char* ICACHE_FLASH_ATTR check_header(void *buf) {
	uint8_t *cd = (uint8_t *)buf;
	uint32_t *buf32 = buf;
	os_printf("%p: %08lX %08lX %08lX %08lX\n", buf, buf32[0], buf32[1], buf32[2], buf32[3]);
	if (cd[0] != 0xEA) return "IROM magic missing";
	if (cd[1] != 4 || cd[2] > 3 || (cd[3]>>4) > 6) return "bad flash header";
	if (((uint16_t *)buf)[3] != 0x4010) return "Invalid entry addr";
	if (((uint32_t *)buf)[2] != 0) return "Invalid start offset";
	return NULL;
}

//===== Cgi to query which firmware needs to be uploaded next
int ICACHE_FLASH_ATTR cgiGetFirmwareNext(HttpdConnData *connData) {
	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.

	uint8 id = system_upgrade_userbin_check();
	httpdStartResponse(connData, 200);
	httpdHeader(connData, "Content-Type", "text/plain");
	httpdHeader(connData, "Content-Length", "9");
	httpdEndHeaders(connData);
	char *next = id == 1 ? "user1.bin" : "user2.bin";
	httpdSend(connData, next, -1);
	os_printf("Next firmware: %s (got %d)\n", next, id);

	return HTTPD_CGI_DONE;
}

//===== Cgi that allows the firmware to be replaced via http POST
int ICACHE_FLASH_ATTR cgiUploadFirmware(HttpdConnData *connData) {
	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.

	int offset = connData->post->received - connData->post->buffLen;
	if (offset == 0) {
		connData->cgiPrivData = NULL;
	} else if (connData->cgiPrivData != NULL) {
		// we have an error condition, do nothing
		return HTTPD_CGI_DONE;
	}

	// assume no error yet...
	char *err = NULL;
	int code = 400;

	// check overall size
	//os_printf("FW: %d (max %d)\n", connData->post->len, FIRMWARE_SIZE);
	if (connData->post->len > FIRMWARE_SIZE) err = "Firmware image too large";
	if (connData->post->buff == NULL || connData->requestType != HTTPD_METHOD_POST ||
			connData->post->len < 1024) err = "Invalid request";

	// check that data starts with an appropriate header
	if (err == NULL && offset == 0) err = check_header(connData->post->buff);

	// make sure we're buffering in 1024 byte chunks
	if (err == NULL && offset % 1024 != 0) {
		err = "Buffering problem";
		code = 500;
	}

	// return an error if there is one
	if (err != NULL) {
		os_printf("Error %d: %s\n", code, err);
		httpdStartResponse(connData, code);
		httpdHeader(connData, "Content-Type", "text/plain");
		//httpdHeader(connData, "Content-Length", strlen(err)+2);
		httpdEndHeaders(connData);
		httpdSend(connData, err, -1);
		httpdSend(connData, "\r\n", -1);
		connData->cgiPrivData = (void *)1;
		return HTTPD_CGI_DONE;
	}

	// let's see which partition we need to flash and what flash address that puts us at
	uint8 id = system_upgrade_userbin_check();
	int address = id == 1 ? 4*1024                   // either start after 4KB boot partition
	    : 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024; // 4KB boot, fw1, 16KB user param, 4KB reserved
	address += offset;

	// erase next flash block if necessary
	if (address % SPI_FLASH_SEC_SIZE == 0){
		os_printf("Flashing 0x%05x (id=%d)\n", address, 2-id);
		spi_flash_erase_sector(address/SPI_FLASH_SEC_SIZE);
	}

	// Write the data
	//os_printf("Writing %d bytes at 0x%05x (%d of %d)\n", connData->post->buffSize, address,
	//		connData->post->received, connData->post->len);
	spi_flash_write(address, (uint32 *)connData->post->buff, connData->post->buffLen);

	if (connData->post->received == connData->post->len){
		httpdStartResponse(connData, 200);
		httpdEndHeaders(connData);
		return HTTPD_CGI_DONE;
	} else {
		return HTTPD_CGI_MORE;
	}
}

static ETSTimer flash_reboot_timer;

// Handle request to reboot into the new firmware
int ICACHE_FLASH_ATTR cgiRebootFirmware(HttpdConnData *connData) {
	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.

	// sanity-check that the 'next' partition actually contains something that looks like
	// valid firmware
	uint8 id = system_upgrade_userbin_check();
	int address = id == 1 ? 4*1024                   // either start after 4KB boot partition
	    : 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024; // 4KB boot, fw1, 16KB user param, 4KB reserved
	uint32 buf[8];
	spi_flash_read(address, buf, sizeof(buf));
	char *err = check_header(buf);
	if (err != NULL) {
		os_printf("Error %d: %s\n", 400, err);
		httpdStartResponse(connData, 400);
		httpdHeader(connData, "Content-Type", "text/plain");
		//httpdHeader(connData, "Content-Length", strlen(err)+2);
		httpdEndHeaders(connData);
		httpdSend(connData, err, -1);
		httpdSend(connData, "\r\n", -1);
		return HTTPD_CGI_DONE;
	}

	httpdStartResponse(connData, 200);
	httpdHeader(connData, "Content-Length", "0");
	httpdEndHeaders(connData);

	// Schedule a reboot
	system_upgrade_flag_set(UPGRADE_FLAG_FINISH);
	os_timer_disarm(&flash_reboot_timer);
	os_timer_setfn(&flash_reboot_timer, (os_timer_func_t *)system_upgrade_reboot, NULL);
	os_timer_arm(&flash_reboot_timer, 2000, 1);
	return HTTPD_CGI_DONE;
}