/*
 * Copyright (C) Valentin V. Bartenev
 * Copyright (C) NGINX, Inc.
 */

#include <nxt_main.h>
#include <nxt_conf.h>
#include <nxt_application.h>


typedef struct {
    nxt_str_t        name;
    nxt_conf_type_t  type;
    nxt_int_t        (*validator)(nxt_conf_validation_t *vldt,
                                  nxt_conf_value_t *value, void *data);
    void             *data;
} nxt_conf_vldt_object_t;


typedef nxt_int_t (*nxt_conf_vldt_member_t)(nxt_conf_validation_t *vldt,
                                            nxt_str_t *name,
                                            nxt_conf_value_t *value);

typedef nxt_int_t (*nxt_conf_vldt_system_t)(nxt_conf_validation_t *vldt,
                                            char *name);


static nxt_int_t nxt_conf_vldt_type(nxt_conf_validation_t *vldt,
    nxt_str_t *name, nxt_conf_value_t *value, nxt_conf_type_t type);
static nxt_int_t nxt_conf_vldt_error(nxt_conf_validation_t *vldt,
    const char *fmt, ...);

static nxt_int_t nxt_conf_vldt_listener(nxt_conf_validation_t *vldt,
    nxt_str_t *name, nxt_conf_value_t *value);
static nxt_int_t nxt_conf_vldt_app_name(nxt_conf_validation_t *vldt,
    nxt_conf_value_t *value, void *data);
static nxt_int_t nxt_conf_vldt_app(nxt_conf_validation_t *vldt,
    nxt_str_t *name, nxt_conf_value_t *value);
static nxt_int_t nxt_conf_vldt_object(nxt_conf_validation_t *vldt,
    nxt_conf_value_t *value, void *data);
static nxt_int_t nxt_conf_vldt_object_iterator(nxt_conf_validation_t *vldt,
    nxt_conf_value_t *value, void *data);
static nxt_int_t nxt_conf_vldt_system(nxt_conf_validation_t *vldt,
    nxt_conf_value_t *value, void *data);
static nxt_int_t nxt_conf_vldt_user(nxt_conf_validation_t *vldt, char *name);
static nxt_int_t nxt_conf_vldt_group(nxt_conf_validation_t *vldt, char *name);


static nxt_conf_vldt_object_t  nxt_conf_vldt_root_members[] = {
    { nxt_string("listeners"),
      NXT_CONF_OBJECT,
      &nxt_conf_vldt_object_iterator,
      (void *) &nxt_conf_vldt_listener },

    { nxt_string("applications"),
      NXT_CONF_OBJECT,
      &nxt_conf_vldt_object_iterator,
      (void *) &nxt_conf_vldt_app },

    { nxt_null_string, 0, NULL, NULL }
};


static nxt_conf_vldt_object_t  nxt_conf_vldt_listener_members[] = {
    { nxt_string("application"),
      NXT_CONF_STRING,
      &nxt_conf_vldt_app_name,
      NULL },

    { nxt_null_string, 0, NULL, NULL }
};


static nxt_conf_vldt_object_t  nxt_conf_vldt_app_limits_members[] = {
    { nxt_string("timeout"),
      NXT_CONF_INTEGER,
      NULL,
      NULL },

    { nxt_string("requests"),
      NXT_CONF_INTEGER,
      NULL,
      NULL },

    { nxt_null_string, 0, NULL, NULL }
};


static nxt_conf_vldt_object_t  nxt_conf_vldt_python_members[] = {
    { nxt_string("type"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("workers"),
      NXT_CONF_INTEGER,
      NULL,
      NULL },

    { nxt_string("limits"),
      NXT_CONF_OBJECT,
      &nxt_conf_vldt_object,
      (void *) &nxt_conf_vldt_app_limits_members },

    { nxt_string("user"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_user },

    { nxt_string("group"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_group },

    { nxt_string("working_directory"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("home"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("path"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("module"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_null_string, 0, NULL, NULL }
};


static nxt_conf_vldt_object_t  nxt_conf_vldt_php_members[] = {
    { nxt_string("type"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("workers"),
      NXT_CONF_INTEGER,
      NULL,
      NULL },

    { nxt_string("limits"),
      NXT_CONF_OBJECT,
      &nxt_conf_vldt_object,
      (void *) &nxt_conf_vldt_app_limits_members },

    { nxt_string("user"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_user },

    { nxt_string("group"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_group },

    { nxt_string("working_directory"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("root"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("script"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("index"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_null_string, 0, NULL, NULL }
};


static nxt_conf_vldt_object_t  nxt_conf_vldt_go_members[] = {
    { nxt_string("type"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("workers"),
      NXT_CONF_INTEGER,
      NULL,
      NULL },

    { nxt_string("limits"),
      NXT_CONF_OBJECT,
      &nxt_conf_vldt_object,
      (void *) &nxt_conf_vldt_app_limits_members },

    { nxt_string("user"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_user },

    { nxt_string("group"),
      NXT_CONF_STRING,
      nxt_conf_vldt_system,
      (void *) &nxt_conf_vldt_group },

    { nxt_string("working_directory"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_string("executable"),
      NXT_CONF_STRING,
      NULL,
      NULL },

    { nxt_null_string, 0, NULL, NULL }
};


nxt_int_t
nxt_conf_validate(nxt_conf_validation_t *vldt)
{
    nxt_int_t  ret;

    ret = nxt_conf_vldt_type(vldt, NULL, vldt->conf, NXT_CONF_OBJECT);

    if (ret != NXT_OK) {
        return ret;
    }

    return nxt_conf_vldt_object(vldt, vldt->conf, nxt_conf_vldt_root_members);
}


static nxt_int_t
nxt_conf_vldt_type(nxt_conf_validation_t *vldt, nxt_str_t *name,
    nxt_conf_value_t *value, nxt_conf_type_t type)
{
    nxt_uint_t  value_type;

    static const char  *type_name[] = {
        "a null",
        "a boolean",
        "an integer",
        "a number",
        "a string",
        "an array",
        "an object"
    };

    value_type = nxt_conf_type(value);

    if (value_type == type) {
        return NXT_OK;
    }

    if (name == NULL) {
        return nxt_conf_vldt_error(vldt,
                                   "The configuration must be %s, not %s.",
                                   type_name[type], type_name[value_type]);
    }

    return nxt_conf_vldt_error(vldt,
                               "The \"%V\" value must be %s, not %s.",
                               name, type_name[type], type_name[value_type]);
}


static nxt_int_t
nxt_conf_vldt_error(nxt_conf_validation_t *vldt, const char *fmt, ...)
{
    u_char   *p, *end;
    size_t   size;
    va_list  args;
    u_char   error[NXT_MAX_ERROR_STR];

    va_start(args, fmt);
    end = nxt_vsprintf(error, error + NXT_MAX_ERROR_STR, fmt, args);
    va_end(args);

    size = end - error;

    p = nxt_mp_nget(vldt->pool, size);
    if (p == NULL) {
        return NXT_ERROR;
    }

    nxt_memcpy(p, error, size);

    vldt->error.length = size;
    vldt->error.start = p;

    return NXT_DECLINED;
}


static nxt_int_t
nxt_conf_vldt_listener(nxt_conf_validation_t *vldt, nxt_str_t *name,
    nxt_conf_value_t *value)
{
    nxt_int_t  ret;

    ret = nxt_conf_vldt_type(vldt, name, value, NXT_CONF_OBJECT);

    if (ret != NXT_OK) {
        return ret;
    }

    return nxt_conf_vldt_object(vldt, value, nxt_conf_vldt_listener_members);
}


static nxt_int_t
nxt_conf_vldt_app_name(nxt_conf_validation_t *vldt, nxt_conf_value_t *value,
    void *data)
{
    nxt_str_t         name;
    nxt_conf_value_t  *apps, *app;

    static nxt_str_t  apps_str = nxt_string("applications");

    nxt_conf_get_string(value, &name);

    apps = nxt_conf_get_object_member(vldt->conf, &apps_str, NULL);

    if (nxt_slow_path(apps == NULL)) {
        goto error;
    }

    app = nxt_conf_get_object_member(apps, &name, NULL);

    if (nxt_slow_path(app == NULL)) {
        goto error;
    }

    return NXT_OK;

error:

    return nxt_conf_vldt_error(vldt, "Listening socket is assigned for "
                                     "a non existing application \"%V\".",
                                     &name);
}


static nxt_int_t
nxt_conf_vldt_app(nxt_conf_validation_t *vldt, nxt_str_t *name,
    nxt_conf_value_t *value)
{
    nxt_int_t              ret;
    nxt_str_t              type;
    nxt_thread_t           *thread;
    nxt_conf_value_t       *type_value;
    nxt_app_lang_module_t  *lang;

    static nxt_str_t  type_str = nxt_string("type");

    static void  *members[] = {
        nxt_conf_vldt_python_members,
        nxt_conf_vldt_php_members,
        nxt_conf_vldt_go_members,
    };

    ret = nxt_conf_vldt_type(vldt, name, value, NXT_CONF_OBJECT);

    if (ret != NXT_OK) {
        return ret;
    }

    type_value = nxt_conf_get_object_member(value, &type_str, NULL);

    if (type_value == NULL) {
        return nxt_conf_vldt_error(vldt,
                           "Application must have the \"type\" property set.");
    }

    ret = nxt_conf_vldt_type(vldt, &type_str, type_value, NXT_CONF_STRING);

    if (ret != NXT_OK) {
        return ret;
    }

    nxt_conf_get_string(type_value, &type);

    thread = nxt_thread();

    lang = nxt_app_lang_module(thread->runtime, &type);
    if (lang == NULL) {
        return nxt_conf_vldt_error(vldt,
                                   "The module to run \"%V\" is not found "
                                   "among the available application modules.",
                                   &type);
    }

    return nxt_conf_vldt_object(vldt, value, members[lang->type]);
}


static nxt_int_t
nxt_conf_vldt_object(nxt_conf_validation_t *vldt, nxt_conf_value_t *value,
    void *data)
{
    uint32_t                index;
    nxt_int_t               ret;
    nxt_str_t               name;
    nxt_conf_value_t        *member;
    nxt_conf_vldt_object_t  *vals;

    index = 0;

    for ( ;; ) {
        member = nxt_conf_next_object_member(value, &name, &index);

        if (member == NULL) {
            return NXT_OK;
        }

        vals = data;

        for ( ;; ) {
            if (vals->name.length == 0) {
                return nxt_conf_vldt_error(vldt, "Unknown parameter \"%V\".",
                                           &name);
            }

            if (!nxt_strstr_eq(&vals->name, &name)) {
                vals++;
                continue;
            }

            ret = nxt_conf_vldt_type(vldt, &name, member, vals->type);

            if (ret != NXT_OK) {
                return ret;
            }

            if (vals->validator != NULL) {
                ret = vals->validator(vldt, member, vals->data);

                if (ret != NXT_OK) {
                    return ret;
                }
            }

            break;
        }
    }
}


static nxt_int_t
nxt_conf_vldt_object_iterator(nxt_conf_validation_t *vldt,
    nxt_conf_value_t *value, void *data)
{
    uint32_t                index;
    nxt_int_t               ret;
    nxt_str_t               name;
    nxt_conf_value_t        *member;
    nxt_conf_vldt_member_t  validator;

    validator = (nxt_conf_vldt_member_t) data;
    index = 0;

    for ( ;; ) {
        member = nxt_conf_next_object_member(value, &name, &index);

        if (member == NULL) {
            return NXT_OK;
        }

        ret = validator(vldt, &name, member);

        if (ret != NXT_OK) {
            return ret;
        }
    }
}


static nxt_int_t
nxt_conf_vldt_system(nxt_conf_validation_t *vldt, nxt_conf_value_t *value,
    void *data)
{
    size_t                  length;
    nxt_str_t               name;
    nxt_conf_vldt_system_t  validator;
    char                    string[32];

    /* The cast is required by Sun C. */
    validator = (nxt_conf_vldt_system_t) data;

    nxt_conf_get_string(value, &name);

    length = name.length + 1;
    length = nxt_min(length, sizeof(string));

    nxt_cpystrn((u_char *) string, name.start, length);

    return validator(vldt, string);
}


static nxt_int_t
nxt_conf_vldt_user(nxt_conf_validation_t *vldt, char *user)
{
    struct passwd  *pwd;

    nxt_errno = 0;

    pwd = getpwnam(user);

    if (pwd != NULL) {
        return NXT_OK;
    }

    if (nxt_errno == 0) {
        return nxt_conf_vldt_error(vldt, "User \"%s\" is not found.", user);
    }

    return NXT_ERROR;
}


static nxt_int_t
nxt_conf_vldt_group(nxt_conf_validation_t *vldt, char *group)
{
    struct group  *grp;

    nxt_errno = 0;

    grp = getgrnam(group);

    if (grp != NULL) {
        return NXT_OK;
    }

    if (nxt_errno == 0) {
        return nxt_conf_vldt_error(vldt, "Group \"%s\" is not found.", group);
    }

    return NXT_ERROR;
}