/* Copyright (c) 2010-2016 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "compat.h"
#include "lib-signals.h"
#include "base64.h"
#include "ioloop.h"
#include "str.h"
#include "istream.h"
#include "ostream.h"
#include "strescape.h"
#include "settings-parser.h"
#include "iostream-ssl.h"
#include "iostream-temp.h"
#include "istream-seekable.h"
#include "master-service.h"
#include "master-service-ssl.h"
#include "master-service-settings.h"
#include "mail-storage-service.h"
#include "http-server.h"
#include "http-request.h"
#include "http-response.h"
#include "http-url.h"
#include "doveadm-util.h"
#include "doveadm-server.h"
#include "doveadm-mail.h"
#include "doveadm-print.h"
#include "doveadm-settings.h"
#include "client-connection-private.h"
#include "json-parser.h"

#include <unistd.h>
#include <ctype.h>

struct client_connection_http {
	struct client_connection client;
	struct http_server_connection *http_client;
	struct http_server_request *http_server_request;
	const struct http_request *http_request;
	struct http_server_response *http_response;
	struct json_parser *json_parser;
	const struct doveadm_cmd_ver2 *cmd;
	struct doveadm_cmd_param *cmd_param;
	ARRAY_TYPE(doveadm_cmd_param_arr_t) pargv;
	int method_err;
	char *method_id;
	bool first_row;
	bool value_is_array;
	enum {
		JSON_STATE_INIT,
		JSON_STATE_COMMAND,
		JSON_STATE_COMMAND_NAME,
		JSON_STATE_COMMAND_PARAMETERS,
		JSON_STATE_COMMAND_PARAMETER_KEY,
		JSON_STATE_COMMAND_PARAMETER_VALUE,
		JSON_STATE_COMMAND_ID,
		JSON_STATE_COMMAND_DONE,
		JSON_STATE_DONE
	} json_state;
};

static struct http_server *doveadm_http_server;

static void doveadm_http_server_handle_request(void *context, struct http_server_request *req);
static void doveadm_http_server_connection_destroy(void *context, const char *reason);

static const struct http_server_callbacks doveadm_http_callbacks = {
        .connection_destroy = doveadm_http_server_connection_destroy,
        .handle_request = doveadm_http_server_handle_request
};

static void doveadm_http_server_process_request(void *context);

struct client_connection *
client_connection_create_http(int fd, bool ssl)
{
	struct client_connection_http *conn;
	pool_t pool;

	pool = pool_alloconly_create("doveadm client", 1024*16);
	conn = p_new(pool, struct client_connection_http, 1);
	conn->client.pool = pool;

	if (client_connection_init(&conn->client, fd) < 0)
		return NULL;

	conn->http_client = http_server_connection_create(doveadm_http_server,
			fd, fd, ssl, &doveadm_http_callbacks, conn);
	conn->client.fd = -1;
	return &conn->client;
}

static void
doveadm_http_server_connection_destroy(void *context, const char *reason ATTR_UNUSED)
{
	struct client_connection *conn = context;
	client_connection_destroy(&conn);
}

static void
doveadm_http_server_request_destroy(void *context)
{
        struct client_connection_http *conn = context;
	struct http_server_response *resp = 
		http_server_request_get_response(conn->http_server_request);

	if (resp != NULL) {
		const char *agent;
		const char *url;
		int status;
		const char *reason;
		uoff_t size;
		http_server_response_get_status(resp, &status, &reason);
		size = http_server_response_get_total_size(resp);
		agent = http_request_header_get(conn->http_request, "User-Agent");
		if (agent == NULL) agent = "";
		url = http_url_create(conn->http_request->target.url);
		i_info("doveadm: %s %s %s \"%s %s HTTP/%d.%d\" %d %"PRIuUOFF_T" \"%s\" \"%s\"",
			net_ip2addr(&conn->client.remote_ip), "-", "-",
			conn->http_request->method,
			conn->http_request->target.url->path,
			conn->http_request->version_major, conn->http_request->version_minor,
			status, size,
			url,
			agent);
	}
	if (conn->json_parser != NULL) {
		const char *error ATTR_UNUSED;
		(void)json_parser_deinit(&conn->json_parser, &error);
		// we've already failed, ignore error
	}
	http_server_request_unref(&(conn->http_server_request));
	http_server_switch_ioloop(doveadm_http_server);
        http_server_connection_unref(&(conn->http_client));
	conn->http_client = NULL;
}

static void doveadm_http_server_json_error(void *context, const char *error)
{
	struct client_connection_http *conn = context;
	string_t *escaped;
	o_stream_nsend_str(conn->client.output,"[\"error\",{\"type\":\"");
	escaped = str_new(conn->client.pool, 10);
	json_append_escaped(escaped, error);
	o_stream_nsend_str(conn->client.output,str_c(escaped));
	o_stream_nsend_str(conn->client.output,"\", \"exitCode\":");
        str_truncate(escaped,0);
	str_printfa(escaped,"%d", doveadm_exit_code);
	o_stream_nsend_str(conn->client.output, str_c(escaped));
	o_stream_nsend_str(conn->client.output,"},\"");
	str_truncate(escaped,0);
	if (conn->method_id != NULL) {
	        json_append_escaped(escaped, conn->method_id);
		o_stream_nsend_str(conn->client.output, str_c(escaped));
	}
	o_stream_nsend_str(conn->client.output,"\"]");
}

static void doveadm_http_server_json_success(void *context, struct istream *result)
{
	struct client_connection_http *conn = context;
	string_t *escaped;
	escaped = str_new(conn->client.pool, 10);
	o_stream_nsend_str(conn->client.output,"[\"doveadmResponse\",");
	o_stream_send_istream(conn->client.output, result);
	o_stream_nsend_str(conn->client.output,",\"");
	if (conn->method_id != NULL) {
		json_append_escaped(escaped, conn->method_id);
		o_stream_nsend_str(conn->client.output, str_c(escaped));
	}
	o_stream_nsend_str(conn->client.output,"\"]");
}

/**
 * this is to ensure we can handle arrays and other special parameter types
 */
static int doveadm_http_server_json_parse_next(struct client_connection_http *conn, enum json_type *type, const char **value)
{
	int rc;
	const char *tmp;
	if (conn->json_state == JSON_STATE_COMMAND_PARAMETER_VALUE) {
		if (conn->cmd_param->type == CMD_PARAM_ISTREAM) {
			if (conn->cmd_param->value_set == TRUE)
				return json_parse_next(conn->json_parser, type, value);
			struct istream* is[2] = {0};
			rc = json_parse_next_stream(conn->json_parser, &is[0]);
			if (rc != 1) return rc;
			conn->cmd_param->value_set = TRUE;
			conn->cmd_param->value.v_istream = i_stream_create_seekable_path(is, IO_BLOCK_SIZE, "/tmp/doveadm.");
			rc = json_parse_next(conn->json_parser, type, value);
			conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
			return rc;
		}
		rc = json_parse_next(conn->json_parser, type, value);
		if (rc != 1) return rc;
		if (*type == JSON_TYPE_ARRAY_END) {
			conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
			return json_parse_next(conn->json_parser, type, value);
		}
		/* allow array for cmd_param_array only, and only once */
		if (*type == JSON_TYPE_ARRAY && conn->cmd_param->type != CMD_PARAM_ARRAY)
			return -2;
		if (*type == JSON_TYPE_ARRAY) { /* start of array */
			conn->value_is_array = TRUE;
			rc = json_parse_next(conn->json_parser, type, value);
			if (rc != 1) return rc;
		}
		if (conn->cmd_param->type == CMD_PARAM_ARRAY) {
			if (*type != JSON_TYPE_STRING) {
				/* FIXME: should handle other than string too */
				return -2;
			}
			conn->cmd_param->value_set = TRUE;
			if (!array_is_created(&conn->cmd_param->value.v_array))
				p_array_init(&conn->cmd_param->value.v_array,conn->client.pool,1);
			if (conn->value_is_array) {
				while(rc == 1) {
					tmp = p_strdup(conn->client.pool,*value);
					array_append(&conn->cmd_param->value.v_array, &tmp, 1);
					rc = json_parse_next(conn->json_parser, type, value);
					if (*type == JSON_TYPE_ARRAY_END) {
						conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
						return json_parse_next(conn->json_parser, type, value);
					}
				}
			} else {
				tmp = p_strdup(conn->client.pool,*value);
				array_append(&conn->cmd_param->value.v_array, &tmp, 1);
				conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
				return json_parse_next(conn->json_parser, type, value);
			}
			return rc;
		} else {
			conn->cmd_param->value_set = TRUE;
			switch(conn->cmd_param->type) {
				case CMD_PARAM_BOOL:
					conn->cmd_param->value.v_bool = (strcmp(*value,"true")==0); break;
				case CMD_PARAM_INT64:
					if (str_to_int64(*value, &conn->cmd_param->value.v_int64) != 0) {
						conn->method_err = 400;
					}
					break;
				case CMD_PARAM_STR:
					conn->cmd_param->value.v_string = p_strdup(conn->client.pool, *value); break;
				default:
					break;
			}
		}
		rc = json_parse_next(conn->json_parser, type, value);
		conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
		return rc;
	} else {
		rc = json_parse_next(conn->json_parser, type, value); /* just get next */
		return rc;
	}
}

static void
doveadm_http_server_command_execute(struct client_connection_http *conn)
{
        const struct doveadm_cmd_param *cpar;
	int rc;

	/* final preflight check */
	if (!doveadm_client_is_allowed_command(conn->client.set, conn->cmd->name))
		conn->method_err = 403;
	if (conn->method_err != 0) {
		if (conn->method_err == 404) {
			doveadm_http_server_json_error(conn, "unknownMethod");
		} else if (conn->method_err == 403) {
			doveadm_http_server_json_error(conn, "unAuthorized");
		} else if (conn->method_err == 400) {
			doveadm_http_server_json_error(conn, "invalidRequest");
		} else {
			doveadm_http_server_json_error(conn, "internalError");
		}
		return;
	}

	int pargc;
	struct istream *is;
	struct ioloop *ioloop,*prev_ioloop = current_ioloop;

	// create iostream
	doveadm_print_ostream = iostream_temp_create("/tmp/doveadm.", 0);

	doveadm_print_init(DOVEADM_PRINT_TYPE_JSON);
	/* then call it */
	cpar = array_get(&conn->pargv, (unsigned int*)&pargc);
	ioloop = io_loop_create();
	lib_signals_reset_ioloop();
	doveadm_exit_code = 0;
	rc = conn->cmd->cmd(conn->cmd,pargc, cpar);

	io_loop_set_current(prev_ioloop);
	lib_signals_reset_ioloop();
	o_stream_switch_ioloop(conn->client.output);
	io_loop_set_current(ioloop);
	io_loop_destroy(&ioloop);

	doveadm_print_deinit();
	if (o_stream_nfinish(doveadm_print_ostream)<0) {
		i_info("doveadm(%s): Error writing output in command %s: %s",
		       i_stream_get_name(conn->client.input), conn->cmd->name,
		       o_stream_get_error(conn->client.output));
		doveadm_exit_code = EX_TEMPFAIL;
	}

	is = iostream_temp_finish(&doveadm_print_ostream, 4096);
	doveadm_print_ostream = NULL;

	if (conn->first_row == TRUE) {
		conn->first_row = FALSE;
	} else {
		o_stream_nsend_str(conn->client.output,",");
	}

	if (rc != 0 || doveadm_exit_code != 0) {
		if (doveadm_exit_code == 0 || doveadm_exit_code == EX_TEMPFAIL)
			i_error("doveadm(%s): Command %s failed", i_stream_get_name(conn->client.input), conn->cmd->name);
		doveadm_http_server_json_error(conn, "exitCode");
	} else {
		doveadm_http_server_json_success(conn, is);
	}
	i_stream_unref(&is);
}

static void
doveadm_http_server_read_request(struct client_connection_http *conn)
{
	enum json_type type;
	const char *value, *error;
	const struct doveadm_cmd_ver2 *ccmd;
	struct doveadm_cmd_param *par;
	int rc;
	bool found;

	if (conn->json_parser == NULL)
		conn->json_parser = json_parser_init_flags(conn->client.input, JSON_PARSER_NO_ROOT_OBJECT);

	while((rc = doveadm_http_server_json_parse_next(conn, &type, &value)) == 1) {
		if (conn->json_state == JSON_STATE_INIT) {
			if (type != JSON_TYPE_ARRAY) break;
			conn->json_state = JSON_STATE_COMMAND;
			conn->first_row = TRUE;
			o_stream_nsend_str(conn->client.output,"[");
		} else if (conn->json_state == JSON_STATE_COMMAND) {
			if (type == JSON_TYPE_ARRAY_END) {
				conn->json_state = JSON_STATE_DONE;
				continue;
			}
			if (type != JSON_TYPE_ARRAY) break;
			conn->method_err = 0;
			if (conn->method_id != NULL)
				p_free(conn->client.pool, conn->method_id);
			conn->method_id = NULL;
			conn->cmd = NULL;
			array_clear(&conn->pargv);
			conn->json_state = JSON_STATE_COMMAND_NAME;
		} else if (conn->json_state == JSON_STATE_COMMAND_NAME) {
			if (type != JSON_TYPE_STRING) break;
			/* see if we can find it */
			found = FALSE;
			array_foreach(&doveadm_cmds_ver2, ccmd) {
				if (i_strccdascmp(ccmd->name, value) == 0) {
					conn->cmd = ccmd;
					found = TRUE;
					break;
				}
			}
			if (!found) {
				json_parse_skip_next(conn->json_parser);
				conn->json_state = JSON_STATE_COMMAND_ID;
				conn->method_err = 404;
			} else {
			        const struct doveadm_cmd_param *cpar;
				/* initialize pargv */
				for(cpar = conn->cmd->parameters; cpar->name != NULL; cpar++)
					array_append(&conn->pargv, cpar, 1);
				conn->json_state = JSON_STATE_COMMAND_PARAMETERS;
			}
		} else if (conn->json_state == JSON_STATE_COMMAND_PARAMETERS) {
			if (type == JSON_TYPE_OBJECT_END) {
				conn->json_state = JSON_STATE_COMMAND_ID;
				continue;
			}
			if (type != JSON_TYPE_OBJECT) break;
			conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
		} else if (conn->json_state == JSON_STATE_COMMAND_PARAMETER_KEY) {
                        if (type == JSON_TYPE_OBJECT_END) {
				conn->json_state = JSON_STATE_COMMAND_ID;
				continue;
			}
			// can happen...
			if (type != JSON_TYPE_OBJECT_KEY && type != JSON_TYPE_STRING) break;
			/* go hunting */
			found = FALSE;
			array_foreach_modifiable(&conn->pargv, par) {
				if (i_strccdascmp(par->name, value) == 0) {
					/* it's already set, cannot have same key twice in json */
					if (par->value_set) break;
					conn->cmd_param = par;
					found = TRUE;
					break;
				}
			}
			/* skip parameters if error has already occured */
			if (!found || conn->method_err != 0) {
				json_parse_skip_next(conn->json_parser);
				conn->json_state = JSON_STATE_COMMAND_PARAMETER_KEY;
				conn->method_err = 400;
			} else {
				if (conn->cmd_param->value_set) {
					// FIXME: should be returned as error to client, not logged
					i_info("doveadm(%s): Parameter %s already set",
					       i_stream_get_name(conn->client.input),
					       conn->cmd_param->name);
					break;
				}
				conn->value_is_array = FALSE;
				conn->json_state = JSON_STATE_COMMAND_PARAMETER_VALUE;
			}
		} else if (conn->json_state == JSON_STATE_COMMAND_ID) {
			if (type != JSON_TYPE_STRING) break;
			conn->method_id = p_strdup(conn->client.pool, value);
			conn->json_state = JSON_STATE_COMMAND_DONE;
		} else if (conn->json_state == JSON_STATE_COMMAND_DONE) {
			/* should be end of array */
			if (type != JSON_TYPE_ARRAY_END) break;
			doveadm_http_server_command_execute(conn);
			conn->json_state = JSON_STATE_COMMAND;
		} else if (conn->json_state == JSON_STATE_DONE) {
			// FIXME: should be returned as error to client, not logged
			i_info("doveadm(%s): Got unexpected elements in JSON data", i_stream_get_name(conn->client.input));
			continue;
		}
	}

	if (!conn->client.input->eof && rc == 0)
		return;

	if ((rc == 1 && conn->json_state != JSON_STATE_DONE)) {
		/* this will happen if the parser above runs into unexpected element, but JSON is OK */
		http_server_request_fail_close(conn->http_server_request, 400, "Unexpected element in input");
		// FIXME: should be returned as error to client, not logged
		i_info("doveadm(%s): unexpected element", i_stream_get_name(conn->client.input));
		return;
	}

	if (conn->client.input->stream_errno != 0) {
		http_server_request_fail_close(conn->http_server_request, 400, "Client disconnected");
		i_info("doveadm(%s): read(client) failed: %s",
		       i_stream_get_name(conn->client.input),
		       i_stream_get_error(conn->client.input));
		return;
	}

	if (json_parser_deinit(&conn->json_parser, &error) != 0) {
		http_server_request_fail_close(conn->http_server_request, 400, "Invalid JSON input");
		// FIXME: should be returned as error to client, not logged
		i_info("doveadm(%s): %s", i_stream_get_name(conn->client.input), error);
		return;
	}

	conn->json_parser = NULL;

	io_remove(&conn->client.io);
	conn->client.io = NULL;
	i_stream_unref(&conn->client.input);
	conn->client.input = NULL;

	if (conn->client.output != NULL)
		o_stream_nsend_str(conn->client.output,"]");

	doveadm_http_server_process_request(conn);
}

static void doveadm_http_server_camelcase_value(string_t *value)
{
	size_t i,k;
	char *ptr = str_c_modifiable(value);
	for(i=0,k=0; i < strlen(ptr);) {
		if (ptr[i] == ' ' || ptr[i] == '-') {
			i++;
			ptr[k++] = i_toupper(ptr[i++]);
		} else ptr[k++] = ptr[i++];
	}
	str_truncate(value, k);
}

static void
doveadm_http_server_send_api(struct client_connection_http *conn)
{
	string_t *tmp = str_new(conn->client.pool, 8);
	size_t i,k;
	const struct doveadm_cmd_ver2 *cmd;
	const struct doveadm_cmd_param *par;
	bool sent;
	o_stream_nsend_str(conn->client.output,"[\n");
	for(i = 0; i < array_count(&doveadm_cmds_ver2); i++) {
		cmd = array_idx(&doveadm_cmds_ver2, i);
		if (i>0) o_stream_nsend_str(conn->client.output, ",\n");
		o_stream_nsend_str(conn->client.output, "\t{\"command\":\"");
		json_append_escaped(tmp, cmd->name);
		doveadm_http_server_camelcase_value(tmp);
		o_stream_nsend_str(conn->client.output, str_c(tmp));
		o_stream_nsend_str(conn->client.output, "\", \"parameters\":[");
		sent = FALSE;
		for(k=0;cmd->parameters[k].name != NULL; k++) {
			str_truncate(tmp, 0);
			par = &(cmd->parameters[k]);
			if ((par->flags & CMD_PARAM_FLAG_DO_NOT_EXPOSE) != 0)
				continue;
			if (sent)
				o_stream_nsend_str(conn->client.output, ",\n");
			else
				o_stream_nsend_str(conn->client.output, "\n");
			sent = TRUE;
			o_stream_nsend_str(conn->client.output, "\t\t{\"name\":\"");
	                json_append_escaped(tmp, par->name);
			doveadm_http_server_camelcase_value(tmp);
			o_stream_nsend_str(conn->client.output, str_c(tmp));
			o_stream_nsend_str(conn->client.output, "\",\"type\":\"");
			switch(par->type) {
			case CMD_PARAM_BOOL:
				o_stream_nsend_str(conn->client.output, "boolean");
				break;
			case CMD_PARAM_INT64:
				o_stream_nsend_str(conn->client.output, "integer");
				break;
			case CMD_PARAM_ARRAY:
				o_stream_nsend_str(conn->client.output, "array");
				break;
			case CMD_PARAM_ISTREAM:
			case CMD_PARAM_STR:
				o_stream_nsend_str(conn->client.output, "string");
			}
			o_stream_nsend_str(conn->client.output, "\"}");
		}
		if (k>0) o_stream_nsend_str(conn->client.output,"\n\t");
		o_stream_nsend_str(conn->client.output,"]}");
		str_truncate(tmp, 0);
	}
	o_stream_nsend_str(conn->client.output,"\n]");
}

static void
doveadm_http_server_handle_request(void *context, struct http_server_request *req)
{
	struct client_connection_http *conn = context;
	conn->http_server_request = req;
	conn->http_request = http_server_request_get(req);
	const char *path = conn->http_request->target.url->path;

	http_server_connection_ref(conn->http_client);
	http_server_request_set_destroy_callback(req, doveadm_http_server_request_destroy, conn);
	http_server_request_ref(conn->http_server_request);

	if (doveadm_settings->doveadm_api_key != NULL) {
		const char *key;
		key = http_request_header_get(conn->http_request, "X-API-Key");
		if (key == NULL || strcmp(doveadm_settings->doveadm_api_key, key) != 0) {
			http_server_request_fail_close(req, 403, "Not authorized");
			return;
		}
	}

	if (strcmp(conn->http_request->method, "GET") != 0 &&
		strcmp(conn->http_request->method, "POST") != 0) {
		http_server_request_fail_close(req, 405, "Method Not Allowed");
		return;
	}

	if (strcasecmp(path, "/doveadm") != 0) {
		http_server_request_fail_close(req, 404, "Object Not Found");
		return;
	}

	conn->http_response = http_server_response_create(req, 200, "OK");
	http_server_response_add_header(conn->http_response, "Content-Type",
		"application/json; charset=utf-8");

        if (strcmp(conn->http_request->method, "GET") == 0) {
                /* print out API */
		conn->client.output = iostream_temp_create_named("/tmp", 0, net_ip2addr(&conn->client.remote_ip));
                doveadm_http_server_send_api(conn);
		doveadm_http_server_process_request(context);
        } else if (strcmp(conn->http_request->method, "POST") == 0) {
		/* handle request */
		conn->client.input = conn->http_request->payload;
		i_stream_set_name(conn->client.input, net_ip2addr(&conn->client.remote_ip));
		i_stream_ref(conn->client.input);
		conn->client.io = io_add_istream(conn->client.input,
					 doveadm_http_server_read_request, conn);
		conn->client.output = iostream_temp_create_named("/tmp", 0, net_ip2addr(&conn->client.remote_ip));
		p_array_init(&conn->pargv, conn->client.pool, 5);
		doveadm_http_server_read_request(conn);
	} else {
		i_unreached();
	}
}

static void doveadm_http_server_process_request(void *context)
{
	struct client_connection_http *conn = context;

	if (conn->client.output != NULL) {
		if (o_stream_nfinish(conn->client.output) == -1) {
			i_info("doveadm(%s): error writing output: %s",
			       net_ip2addr(&conn->client.remote_ip),
			       o_stream_get_error(conn->client.output));
			http_server_response_update_status(conn->http_response, 500, "Internal server error");
		} else {
			// read the response
			http_server_response_set_payload(conn->http_response, iostream_temp_finish(&conn->client.output, IO_BLOCK_SIZE));
		}
	}
	// submit response
	http_server_response_submit_close(conn->http_response);
}

static const struct http_server_settings http_server_set = {
        .max_pipelined_requests = 0
};

void doveadm_http_server_init(void)
{
	doveadm_http_server = http_server_init(&http_server_set);
	
}

void doveadm_http_server_deinit(void)
{
	http_server_deinit(&doveadm_http_server);
}