#include "kpl.h"

static kpl_config default_config = {
    .argc = -1, .main_module_arg_index = -1,
    .argv = NULL, .module_extension = ".kpl",
    .flags = 0,
    .io = {
        .queue_pow = KPL_IO_QUEUE_POW_DEFAULT
    },
    .thread = {
        .count = -1
    }
};

void kpl_config_init(kpl_config *config) {
    memcpy(config, &default_config, sizeof(kpl_config));
}

typedef int32_t kpl_arg_match_fn(const char *match_str, const int32_t match_str_index, kpl_config *config);

typedef struct {
    const char *match_str, *help_message;
    kpl_arg_match_fn *arg_match_fn;
} kpl_arg_match;


static int32_t kpl_arg_match_module_extension(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    config->module_extension = match_str + match_str_index;
    return KPL_EXIT_CODE_SUCCESS;
}

static int32_t kpl_arg_match_eval(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    (void) match_str;
    (void) match_str_index;
    config->flags |= KPL_CONFIG_FLAG_EVAL;
    return KPL_EXIT_CODE_SUCCESS;
}

static int32_t kpl_arg_match_repl(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    (void) match_str;
    (void) match_str_index;
    config->flags |= KPL_CONFIG_FLAG_REPL;
    return KPL_EXIT_CODE_SUCCESS;
}

static int32_t kpl_arg_match_io_queue_pow(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    int32_t queue_pow = atoi(match_str + match_str_index);
    if (queue_pow < KPL_IO_QUEUE_POW_MIN || queue_pow > KPL_IO_QUEUE_POW_MAX)
        return KPL_EXIT_CODE_ERROR;
    config->io.queue_pow = queue_pow;
    return KPL_EXIT_CODE_SUCCESS;
}

static int32_t kpl_arg_match_thread_count(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    int32_t thread_count = atoi(match_str + match_str_index);
    if (!thread_count)
        return KPL_EXIT_CODE_ERROR;
    config->thread.count = thread_count;
    return KPL_EXIT_CODE_SUCCESS;
}

static int32_t kpl_arg_match_help(const char *match_str, const int32_t match_str_index, kpl_config *config);

static kpl_arg_match arg_match_array[] = {
    {
        .match_str = "--module-extension=",
        .help_message="[WORD], Change the module extension for imports (default .kpl)",
        .arg_match_fn = kpl_arg_match_module_extension
    },
    {
        .match_str = "--eval",
        .help_message = " [STRING...], Evaluate next argument(s) as modules",
        .arg_match_fn = kpl_arg_match_eval
    },
    {
        .match_str = "--io-queue-pow=",
        .help_message = "[NUMBER], Power of two for calculating the size of the io_uring queue",
        .arg_match_fn = kpl_arg_match_io_queue_pow
    },
    {
        .match_str = "--thread-count=",
        .help_message = "[NUMBER], Number of running threads, minimum is 1",
        .arg_match_fn = kpl_arg_match_thread_count
    },
    {
        .match_str = "--repl",
        .help_message = ", Start (R)ead, (E)valuate, (P)rint, (L)oop",
        .arg_match_fn = kpl_arg_match_repl
    },
    { .match_str = "--help", .help_message = ", Show help", .arg_match_fn = kpl_arg_match_help },
    { .match_str = NULL, .help_message = NULL, .arg_match_fn = NULL }
};

static int32_t kpl_arg_match_help(const char *match_str, const int32_t match_str_index, kpl_config *config) {
    (void) match_str;
    (void) match_str_index;
    printf("\nUsage " KPL_COLOR(BOLD) "%s" KPL_COLOR(RESET) KPL_COLOR(WHITE) " [OPTIONS] [MODULE]" KPL_COLOR(RESET)
        KPL_COLOR(BOLD) "%s\n\n" KPL_COLOR(RESET), config->argv[0], config->module_extension);
    printf("Where " KPL_COLOR(WHITE) "[OPTIONS]" KPL_COLOR(RESET) " are:\n");
    const kpl_arg_match *match_array = arg_match_array;
    while (match_array->match_str) {
        printf(KPL_COLOR(LIGHT_YELLOW) "\t%s" KPL_COLOR(RESET) "%s\n",
            match_array->match_str, match_array->help_message);
        match_array++;
    }
    putchar('\n');
    return KPL_EXIT_CODE_HELP;
}

static bool kpl_valid_match_str_index(const char *match_str_array, const char *match_str_arg, int32_t match_str_index) {
    return match_str_array[match_str_index] &&
        match_str_array[match_str_index] == match_str_arg[match_str_index];
}

static bool kpl_valid_match_str(const char *match_str_array, const char *match_str_arg, int32_t match_str_index) {
    return !match_str_array[match_str_index] && (!match_str_arg[match_str_index] ||
        (match_str_arg[match_str_index] && match_str_array[match_str_index - 1] == '='));
}

bool kpl_config_valid_module_exension(kpl_config *config, const char *module_name) {
    size_t name_length = strlen(module_name), module_extension_length = strlen(config->module_extension);
    return name_length > module_extension_length &&
        strcmp(module_name + name_length - module_extension_length, config->module_extension) == 0;
}

int32_t kpl_config_parse_args(kpl_config *config, const int32_t argc, const char *argv[]) {
    config->argc = argc;
    config->argv = argv;
    if (argc == 1) {
        printf(KPL_COLOR(LIGHT_RED) "\nNo Module Specified\n" KPL_COLOR(RESET));
        return kpl_arg_match_help(NULL, 0, config);
    }
    int32_t arg_index = 1;
    while (arg_index < argc && !config->flags) {
        int32_t match_str_index = 0;
        const char *match_str_arg = argv[arg_index];
        const kpl_arg_match *match_array = arg_match_array;
        while (match_array->match_str) {
            while (kpl_valid_match_str_index(match_array->match_str, match_str_arg, match_str_index))
                match_str_index++;
            if (kpl_valid_match_str(match_array->match_str, match_str_arg, match_str_index)) {
                int32_t exit_status = match_array->arg_match_fn(match_str_arg, match_str_index, config);
                if (exit_status != KPL_EXIT_CODE_SUCCESS) {
                    if (exit_status == KPL_EXIT_CODE_ERROR)
                        printf(KPL_COLOR(LIGHT_RED) "\nInvalid Option: " KPL_COLOR(BOLD) "%s\n" KPL_COLOR(RESET),
                            match_str_arg);
                    return exit_status;
                }
                break;
            }
            match_str_index = 0;
            match_array++;
        }
        if (!match_array->match_str)
            break;
        arg_index++;
    }
    config->main_module_arg_index = arg_index;
    if (config->flags) {
        if ((config->flags & KPL_CONFIG_FLAG_EVAL) && argc - arg_index < 1) {
            printf(KPL_COLOR(LIGHT_RED) "\nInvalid EVAL\n" KPL_COLOR(RESET));
            return kpl_arg_match_help(NULL, 0, config);
        }
        if ((config->flags & KPL_CONFIG_FLAG_REPL) && argc != arg_index) {
            printf(KPL_COLOR(LIGHT_RED) "\nInvalid REPL\n" KPL_COLOR(RESET));
            return kpl_arg_match_help(NULL, 0, config);
        }
        return KPL_EXIT_CODE_SUCCESS;
    }
    if (!kpl_config_valid_module_exension(config, argv[arg_index])) {
        printf(KPL_COLOR(LIGHT_RED) "\nInvalid " KPL_COLOR(RESET)
            KPL_COLOR(WHITE) "[OPTION]/[MODULE]: " KPL_COLOR(RESET)
            KPL_COLOR2(BOLD, LIGHT_RED) "%s\n" KPL_COLOR(RESET), argv[arg_index]);
        return kpl_arg_match_help(NULL, 0, config);
    }
    return KPL_EXIT_CODE_SUCCESS;
}