/**
 * sesimos - secure, simple, modern web server
 * @brief Configuration file loader
 * @file src/lib/config.c
 * @author Lorenz Stechauner
 * @date 2021-01-05
 */

#include "../logger.h"
#include "config.h"

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

config_t config;

int config_load(const char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        critical("Unable to open config file");
        return -1;
    }

    memset(&config, 0, sizeof(config));

    int i = 0;
    int j = 0;
    int line_num = 0;
    int mode = 0;
    char section = 0;
    char *source, *target;

    char *line = NULL;
    ssize_t read;
    size_t line_len = 0;
    while ((read = getline(&line, &line_len, file)) != -1) {
        line_num++;
        char *ptr = line;
        char *comment = strpbrk(ptr, "#\r\n");
        if (comment != NULL) comment[0] = 0;

        unsigned long len = strlen(ptr);
        char *end_ptr = ptr + len - 1;
        while (end_ptr[0] == ' ' || end_ptr[0] == '\t') {
            end_ptr[0] = 0;
            end_ptr--;
        }
        len = strlen(ptr);
        if (len == 0) continue;

        if (ptr[0] == '[') {
            if (ptr[len - 1] != ']') goto err;
            ptr++;
            int l = 0;
            if (strncmp(ptr, "host", 4) == 0 && (ptr[4] == ' ' || ptr[4] == '\t')) {
                ptr += 4;
                while (ptr[0] == ' ' || ptr[0] == '\t' || ptr[0] == ']') ptr++;
                while (ptr[l] != ' ' && ptr[l] != '\t' && ptr[l] != ']') l++;
                if (l == 0) goto err;
                snprintf(config.hosts[i].name, sizeof(config.hosts[i].name), "%.*s", l, ptr);
                i++;
                section = 'h';
            } else if (strncmp(ptr, "cert", 4) == 0 && (ptr[4] == ' ' || ptr[4] == '\t')) {
                ptr += 4;
                while (ptr[0] == ' ' || ptr[0] == '\t' || ptr[0] == ']') ptr++;
                while (ptr[l] != ' ' && ptr[l] != '\t' && ptr[l] != ']') l++;
                if (l == 0) goto err;
                snprintf(config.certs[j].name, sizeof(config.certs[j].name), "%.*s", l, ptr);
                j++;
                section = 'c';
            } else {
                goto err;
            }
            continue;
        } else if (section == 0) {
            if (len > 10 && strncmp(ptr, "geoip_dir", 9) == 0 && (ptr[9] == ' ' || ptr[9] == '\t')) {
                source = ptr + 9;
                target = config.geoip_dir;
            } else if (len > 11 && strncmp(ptr, "dns_server", 10) == 0 && (ptr[10] == ' ' || ptr[10] == '\t')) {
                source = ptr + 10;
                target = config.dns_server;
            } else {
                goto err;
            }
        } else if (section == 'c') {
            cert_config_t *cc = &config.certs[j - 1];
            if (len > 12 && strncmp(ptr, "certificate", 11) == 0 && (ptr[11] == ' ' || ptr[11] == '\t')) {
                source = ptr + 11;
                target = cc->full_chain;
            } else if (len > 12 && strncmp(ptr, "private_key", 11) == 0 && (ptr[11] == ' ' || ptr[11] == '\t')) {
                source = ptr + 11;
                target = cc->priv_key;
            } else {
                goto err;
            }
        } else if (section == 'h') {
            host_config_t *hc = &config.hosts[i - 1];
            if (len > 8 && strncmp(ptr, "webroot", 7) == 0 && (ptr[7] == ' ' || ptr[7] == '\t')) {
                source = ptr + 7;
                target = hc->local.webroot;
                if (hc->type != 0 && hc->type != CONFIG_TYPE_LOCAL) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_LOCAL;
                }
            } else if (len > 5 && strncmp(ptr, "cert", 4) == 0 && (ptr[4] == ' ' || ptr[4] == '\t')) {
                source = ptr + 4;
                target = hc->cert_name;
            } else if (len > 9 && strncmp(ptr, "dir_mode", 8) == 0 && (ptr[8] == ' ' || ptr[8] == '\t')) {
                source = ptr + 8;
                target = NULL;
                mode = 1;
                if (hc->type != 0 && hc->type != CONFIG_TYPE_LOCAL) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_LOCAL;
                }
            } else if (len > 9 && strncmp(ptr, "hostname", 8) == 0 && (ptr[8] == ' ' || ptr[8] == '\t')) {
                source = ptr + 8;
                target = hc->proxy.hostname;
                if (hc->type != 0 && hc->type != CONFIG_TYPE_REVERSE_PROXY) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_REVERSE_PROXY;
                }
            } else if (len > 5 && strncmp(ptr, "port", 4) == 0 && (ptr[4] == ' ' || ptr[4] == '\t')) {
                source = ptr + 4;
                target = NULL;
                mode = 2;
                if (hc->type != 0 && hc->type != CONFIG_TYPE_REVERSE_PROXY) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_REVERSE_PROXY;
                }
            } else if (strcmp(ptr, "http") == 0) {
                if (hc->type != 0 && hc->type != CONFIG_TYPE_REVERSE_PROXY) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_REVERSE_PROXY;
                    hc->proxy.enc = 0;
                }
                continue;
            } else if (strcmp(ptr, "https") == 0) {
                if (hc->type != 0 && hc->type != CONFIG_TYPE_REVERSE_PROXY) {
                    goto err;
                } else {
                    hc->type = CONFIG_TYPE_REVERSE_PROXY;
                    hc->proxy.enc = 1;
                }
                continue;
            } else {
                goto err;
            }
        } else {
            goto err;
        }

        while (source[0] == ' ' || source[0] == '\t') source++;
        if (strlen(source) == 0) {
            err:
            critical("Unable to parse config file (line %i)", line);
            return -2;
        }

        if (target != NULL) {
            strcpy(target, source);
        } else if (mode == 1) {
            if (strcmp(source, "forbidden") == 0) {
                config.hosts[i - 1].local.dir_mode = URI_DIR_MODE_FORBIDDEN;
            } else if (strcmp(source, "info") == 0) {
                config.hosts[i - 1].local.dir_mode = URI_DIR_MODE_INFO;
            } else if (strcmp(source, "list") == 0) {
                config.hosts[i - 1].local.dir_mode = URI_DIR_MODE_LIST;
            } else {
                goto err;
            }
        } else if (mode == 2) {
            config.hosts[i - 1].proxy.port = (unsigned short) strtoul(source, NULL, 10);
        }
    }

    free(line);

    for (int k = 0; k < i; k++) {
        host_config_t *hc = &config.hosts[k];
        if (hc->type == CONFIG_TYPE_LOCAL) {
            char *webroot = config.hosts[k].local.webroot;
            if (webroot[strlen(webroot) - 1] == '/') {
                webroot[strlen(webroot) - 1] = 0;
            }
        }
        if (hc->cert_name[0] == 0) goto err2;
        int found = 0;
        for (int m = 0; m < j; m++) {
            if (strcmp(config.certs[m].name, hc->cert_name) == 0) {
                hc->cert = m;
                found = 1;
                break;
            }
        }
        if (!found) {
            err2:
            critical("Unable to parse config file");
            return -2;
        }
    }

    return 0;
}

host_config_t *get_host_config(const char *host) {
    for (int i = 0; i < CONFIG_MAX_HOST_CONFIG; i++) {
        host_config_t *hc = &config.hosts[i];
        if (hc->type == CONFIG_TYPE_UNSET) break;
        if (strcmp(hc->name, host) == 0) return hc;
        if (hc->name[0] == '*' && hc->name[1] == '.') {
            const char *pos = strstr(host, hc->name + 1);
            if (pos != NULL && strlen(pos) == strlen(hc->name + 1)) return hc;
        }
    }
    return NULL;
}