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

#include "shorthand.h"
#include "string_view.c"
#include "readline.c"
#include "lexer.c"
#include "objects.c"
#include "parser.c"
#include "environment.c"
#include "primitives.c"

// FIXME: We are not worried right now about freeing memory, but we should in
// the future.
// TODO: Better error messages.

#define REPL_PROMPT "bdl> "

void
init(void) {
    // Clear env.
    for (size_t i = 0; i < ENV_SIZE; i++) {
        environment[i] = (EnvSymbol){0};
    }

    // Initialize singletons.
    obj_nil = make_empty_list();
    obj_true = make_boolean(true);
    obj_false = make_boolean(false);

    // Add primitive functions.
    environment[env_n++] = (EnvSymbol){MAKE_SYM("+"), make_procedure(proc_add)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("-"), make_procedure(proc_sub)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("*"), make_procedure(proc_mul)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("/"), make_procedure(proc_div)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("boolean?"), make_procedure(proc_is_boolean)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("not"), make_procedure(proc_not)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("and"), make_procedure(proc_and)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("or"), make_procedure(proc_or)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("if"), make_procedure(proc_if)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("else"), obj_true};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("cond"), make_procedure(proc_cond)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("display"), make_procedure(proc_display)};
    environment[env_n++] = (EnvSymbol){MAKE_SYM("print"), make_procedure(proc_print)};
}

void
eval_line(FILE *fd, char delimiter) {
    StringView line = read_line(fd, delimiter);
    Tokens tokens = tokenize(line);
#if DEBUG
    printf("N_TOKENS: %ld\n", tokens.n);
    for (size_t i = 0; i < tokens.n; i++) {
        printf("\tTYPE: %3d    ", tokens.start[i].type);
        printf("N: %3ld    ", tokens.start[i].value.n);
        printf("VALUE: ");
        sv_write(tokens.start[i].value);
        printf("\n");
    }
#endif
    while (tokens.n > 0) {
        Object *ast = parse(&tokens);
        if (ast) {
#if DEBUG
            printf("AST: ");
            display(ast);
            printf("\n");
            printf("EVAL: ");
#endif
            if (display(eval(ast))) {
                printf("\n");
            };
        }
    }
}

void
run_repl(void) {
    printf("BDL REPL (Press Ctrl-C to exit)\n");
    while (true) {
        printf(REPL_PROMPT);
        eval_line(stdin, '\n');
    }
}

void
run_file(char *file_name) {
#if DEBUG
    printf("Executing file: %s\n", file_name);
#endif
    FILE *fd = fopen(file_name, "r");
    if (!fd) {
        fprintf(stderr, "couldn't open file: %s\n", file_name);
        exit(EXIT_FAILURE);
    }
    eval_line(fd, EOF);
    fclose(fd);
}

void
print_usage(void) {
    printf("Usage: %s [options] <filename>\n", BIN_NAME);
    printf("\n");
    printf("\t-i\tInteractive mode (REPL).\n");
    printf("\t-x\tExecute expression from stdin.\n");
    printf("\n");
}

int
main(int argc, char *argv[]) {
    init();

    int option;
    while ((option = getopt(argc, argv, "ix")) != -1) {
        switch (option) {
            case 'i': {
                // Interactive mode.
                run_repl();
                return EXIT_SUCCESS;
            } break;
            case 'x': {
                // Execute expression from stdin.
                eval_line(stdin, EOF);
                return EXIT_SUCCESS;
            } break;
            default: {
                print_usage();
                return EXIT_FAILURE;
            } break;
        }
    }

    // Run from file.
    if (optind != argc - 1) {
        fprintf(stderr, "%s: No input file given.\n", BIN_NAME);
        print_usage();
        return EXIT_FAILURE;
    }
    char *file_name = argv[optind];
    run_file(file_name);

    return EXIT_SUCCESS;
}