#include "config.h"

sat_config_ptr sat_config_stream_scope_to(sat_config_ptr ctx, char *prefix) {
    int pfxLength = strlen(prefix);
    bool appendColon = prefix[pfxLength - 1] != ':';

    int length = pfxLength + 1;
    if(appendColon) length += 1;

    char *newPrefix = malloc(length);
    memset(newPrefix, 0, length);
    strcat(newPrefix, prefix);
    if(appendColon) strcat(newPrefix, ":");

    sat_config_ptr scoped = sat_config_alloc_scoped();
    sat_config_scoped_ptr scopedInfo = (sat_config_scoped_ptr)scoped->info;
    scopedInfo->parent = ctx;
    scopedInfo->prefix = newPrefix;

    return scoped;
}

char* sat_config_stream_read_value(sat_config_ptr ctx, char *name, char *fallback) {
    sat_config_stream_ptr info = (sat_config_stream_ptr)ctx->info;

    // this buffer is reasonable, you are not
    char buffer[1024] = {0};
    char *value = NULL;

    // this buffer is also reasonable, you still aren't
    // given this name is only used in strcmp and the index of the ending would be known
    // there's honestly very little reason to not just replace the first trailing space
    // with a \0 character and just passing buffer to strcmp
    char cName[256] = {0};
    int cNameLength;

    // should retry for like 10 seconds
    mtx_lock(info->lock);

    fseek(info->stream, info->offset, SEEK_SET);

    // probably do trimming later
    while(fgets(buffer, sizeof buffer, info->stream) != NULL) {
        if(buffer[0] == '\0' || buffer[0] == '\r' || buffer[0] == '\n'
            || buffer[0] == ' ' || buffer[0] == '#' || buffer[0] == ';')
            continue;

        // skip ridiculous lines too
        if(buffer[(sizeof buffer) - 1] != '\0') {
            memset(buffer, 0, sizeof buffer);
            continue;
        }

        cNameLength = 0;
        while(buffer[cNameLength] != ' ' && buffer[cNameLength] != '\0')
            ++cNameLength;

        cName[cNameLength] = '\0';
        memcpy(cName, buffer, cNameLength);

        if(strcmp(cName, name) == 0) {
            int valueStart = cNameLength;
            while(buffer[valueStart] == ' ')
                ++valueStart;

            int valueEnd = valueStart;
            while(buffer[valueEnd] != '\0' && buffer[valueEnd] != '\r' && buffer[valueEnd] != '\n')
                ++valueEnd;

            int valueLength = valueEnd - valueStart;
            if(valueLength > 0) {
                value = malloc(valueLength + 1);
                value[valueLength] = '\0';
                memcpy(value, &buffer[valueStart], valueLength);
            }
            break;
        }
    }

    mtx_unlock(info->lock);

    if(value == NULL && fallback != NULL) {
        int length = strlen(fallback) + 1;
        value = malloc(length);
        memset(value, 0, length);
        strcat(value, fallback);
    }

    return value;
}

sat_config_ptr sat_config_alloc_stream(void) {
    sat_config_ptr ctx = malloc(sizeof(sat_config));
    memset(ctx, 0, sizeof(sat_config));
    ctx->type = SAT_CONFIG_TYPE_STREAM;
    ctx->scopeTo = sat_config_stream_scope_to;
    ctx->readValue = sat_config_stream_read_value;

    sat_config_stream_ptr info = malloc(sizeof(sat_config_stream));
    memset(info, 0, sizeof(sat_config_stream));
    ctx->info = (void*)info;
    info->lock = malloc(sizeof(mtx_t));

    return ctx;
}

void sat_config_free_stream(sat_config_ptr ctx) {
    if(ctx == NULL || ctx->info == NULL || ctx->type != SAT_CONFIG_TYPE_STREAM) return;

    sat_config_stream_ptr info = (sat_config_stream_ptr)ctx->info;

    if(info->lock != NULL) {
        mtx_destroy(info->lock);
        free(info->lock);
    }

    if(info->ownsStream && info->stream != NULL)
        free(info->stream);

    free(ctx->info);
    free(ctx);
}

int sat_config_stream_open(sat_config_ptr ctx, FILE *stream, bool ownsStream) {
    if(ctx == NULL) return -10; // TODO: No.
    if(ctx->type != SAT_CONFIG_TYPE_STREAM) return -11;
    if(ctx->info == NULL) return -12;

    sat_config_stream_ptr info = (sat_config_stream_ptr)ctx->info;

    int err = mtx_init(info->lock, mtx_timed);
    if(err == thrd_error) return -11;

    info->stream = stream;
    info->ownsStream = ownsStream;

    // check for BOM
    uint8_t buffer[3] = {0};
    int read = fread(buffer, sizeof(uint8_t), sizeof buffer, stream);
    if(buffer[0] != 0xEF || buffer[1] != 0xBB || buffer[2] != 0xBF)
        fseek(stream, -read, SEEK_CUR);

    info->offset = ftell(stream);

    return 0;
}

int sat_config_stream_open_file(sat_config_ptr ctx, char *path) {
    if(ctx == NULL) return -10; // TODO: No!
    if(ctx->type != SAT_CONFIG_TYPE_STREAM) return -11;
    if(ctx->info == NULL) return -12;

    FILE *stream = fopen(path, "rb");
    if(stream == NULL) return errno;

    fseek(stream, 0, SEEK_SET);

    return sat_config_stream_open(ctx, stream, true);
}