#include "db/sets.h"
#include "jwt/jwt.h"
#include "server/response.h"
#include "server/study.h"
#include "server/types.h"
#include "server/util.h"


#include "db/auth.h"

#include "hash/hash.h"

#include <civetweb.h>

#include <cjson/cJSON.h>

#include <assert.h>
#include <stdlib.h>
#include <string.h>

typedef struct
{
    char* action;
    char* token;
    int id;
    int has_id;
    char* name;
    char* problems;
    char* data;
} set_form_t;

static void set_form_dtor(set_form_t* form)
{
    if (form->action) free(form->action);
    if (form->token) free(form->token);
    if (form->name) free(form->name);
    if (form->problems) free(form->problems);
    if (form->data) free(form->data);
}

static int field_found(const char* key, const char* filename, char* path, size_t pathlen, void* user_data)
{
    return MG_FORM_FIELD_HANDLE_GET;
}

static int field_get(const char* key, const char* value, size_t valuelen, void* user_data)
{
    set_form_t* form = (set_form_t*)user_data;
    if (strcmp(key, "action") == 0) {
        form->action = kqm_strndup(value, valuelen);
    } else if (strcmp(key, "token") == 0) {
        form->token = kqm_strndup(value, valuelen);
    } else if (strcmp(key, "id") == 0) {
        char* id_str = kqm_strndup(value, valuelen);

        form->id     = atoi(id_str);
        form->has_id = 1;
        free(id_str);
    } else if (strcmp(key, "name") == 0) {
        form->name = kqm_strndup(value, valuelen);
    } else if (strcmp(key, "problems") == 0) {
        form->problems = kqm_strndup(value, valuelen);
    } else if (strcmp(key, "data") == 0) {
        form->data = kqm_strndup(value, valuelen);
    }
    return MG_FORM_FIELD_HANDLE_GET;
}

static void impl_add(mg_connection* conn, set_form_t* form)
{
    if (!form->name) {
        res_need_xxx(conn, "name");
        return;
    }
    if (!form->problems) {
        res_need_xxx(conn, "problem ids");
        return;
    }
    if (!form->data) {
        res_need_xxx(conn, "other data");
        return;
    }

    int result;
    int flag = add_set(form->name, form->problems, form->data, &result);
    if (!flag) {
        res_500(conn, "failed to get a set");
        return;
    }

    res_add_set(conn, result);
}

static void impl_delete(mg_connection* conn, set_form_t* form)
{
    if (!form->has_id) {
        res_need_xxx(conn, "set id");
        return;
    }

    int flag = delete_set(form->id);
    if (flag == -1) {
        res_404(conn, "the set does not exist");
    } else if (!flag) {
        res_500(conn, "failed to delete a set");
        return;
    }

    res_200(conn, "successed to delete the set");
}

static void impl_query(mg_connection* conn, set_form_t* form)
{
    if (!form->has_id) {
        res_need_xxx(conn, "set id");
        return;
    }

    char* result = NULL;
    int flag     = get_set(form->id, &result);
    if (!flag) {
        res_500(conn, "failed to get a set");
        return;
    }
    if (!result) {
        res_404(conn, "the set does not exist");
        return;
    }

    res_get_set(conn, result);
    free(result);
}

static void impl_modify(mg_connection* conn, set_form_t* form)
{
    if (!form->has_id) {
        res_need_xxx(conn, "set id");
        return;
    }
    if (!form->name) {
        res_need_xxx(conn, "name");
        return;
    }
    if (!form->problems) {
        res_need_xxx(conn, "problem ids");
        return;
    }
    if (!form->data) {
        res_need_xxx(conn, "other data");
        return;
    }

    int flag = modify_set(form->id, form->name, form->problems, form->data);
    if (!flag) {
        res_500(conn, "failed to modify the set");
        return;
    }

    res_200(conn, "successed to modify the set");
}

static void impl_all(mg_connection* conn, set_form_t* form)
{
    char* result = NULL;
    int flag     = all_sets(&result);
    if (!flag) {
        res_500(conn, "failed to get all sets");
        return;
    }

    res_all_sets(conn, result);
    free(result);
}

int sets_handler(mg_connection* conn, void* cbdata)
{
    const mg_request_info* post_body = mg_get_request_info(conn);

    if (post_body == NULL) {
        res_null_req(conn);
        return 1;
    }

    if (strcmp(post_body->request_method, "POST")) {
        res_must_post(conn);
        return 1;
    }

    set_form_t form = {NULL, NULL, 0, 0, NULL, NULL, NULL};

    mg_form_data_handler set_callback = {
        .field_found = field_found,
        .field_get   = field_get,
        .field_store = NULL,
        .user_data   = &form,
    };

    mg_handle_form_request(conn, &set_callback);


    if (!form.action) {
        res_need_action(conn);
    } else if (!form.token) {
        res_need_token(conn);
    } else {
        char* user_id = get_payload(form.token);
        if (!user_id) {
            res_permission_denied(conn);
            set_form_dtor(&form);
            return 1;
        }
        int result;
        int flag = get_user_permission(user_id, &result);
        if (!flag) {
            res_check_permission_fail(conn);
        } else if (result != 1 && result != 2) {
            res_permission_denied(conn);
        } else {
            if (!strcmp(form.action, "add")) {
                if (result == 2) {
                    res_permission_denied(conn);
                } else {
                    impl_add(conn, &form);
                }
            } else if (!strcmp(form.action, "delete")) {
                if (result == 2) {
                    res_permission_denied(conn);
                } else {
                    impl_delete(conn, &form);
                }
            } else if (!strcmp(form.action, "query")) {
                impl_query(conn, &form);
            } else if (!strcmp(form.action, "modify")) {
                if (result == 2) {
                    res_permission_denied(conn);
                } else {
                    impl_modify(conn, &form);
                }
            } else if (!strcmp(form.action, "all")) {
                impl_all(conn, &form);
            } else {
                res_bad_action(conn);
            }
        }
    }

    set_form_dtor(&form);
    return 1;
}