/*
 * Compiler command-line interface.
 * Copyright (c) 2023-2024, Quinn Stephens and the OSMORA team.
 * Provided under the BSD 3-Clause license.
 */

#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "hashmap.h"
#include "parser/type.h"
#include "parser.h"

#define HASHMAP_ROWS 16

#define OID_O 0x00

struct option {
    char *name;
    char *value;
};

static char *argv0;
static char *in_fname;
static struct option options[] = {
    [OID_O] = { "o", NULL }
};

__attribute__((noreturn)) static void
cmd_fatal(const char *fmt, ...)
{
    va_list ap;

    fprintf(stderr, "\033[1m%s: \033[31mfatal error:\033[0m ", argv0);
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);

    fprintf(stderr, "compilation terminated.\n");
    exit(EXIT_FAILURE);
}

static void
cmd_error(const char *fmt, ...)
{
    va_list ap;

    fprintf(stderr, "\033[1m%s: \033[31merror:\033[0m ", argv0);
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
}

static char *
load_text_file(char *filename)
{
    FILE *fp;
    size_t size;
    char *buf;

    fp = fopen(filename, "rb");
    if (fp == NULL) {
        cmd_error("%s: %s\n", filename, strerror(errno));
        return NULL;
    }

    /* Get file size */
    fseek(fp, 0, SEEK_END);
    size = (size_t)ftell(fp);
    fseek(fp, 0, SEEK_SET);
    if (size < sizeof(char)) {
        cmd_error("%s: empty file\n", filename);
        fclose(fp);
        return NULL;
    }

    /* Read entire file */
    buf = malloc(size + sizeof(char));
    if (fread(buf, 1, size, fp) != size) {
        cmd_error("%s: %s\n", filename, strerror(errno));
        free(buf);
        fclose(fp);
        return NULL;
    }

    fclose(fp);

    /* Terminate string */
    buf[size] = '\0';

    return buf;
}

static struct option *
find_option(char *name)
{
    for (int o = 0; o < (int)(sizeof(options) / sizeof(struct option)); o++) {
        if (strcmp(options[o].name, name) == 0) {
            return &options[0];
        }
    }

    return NULL;
}

static void
set_out_fname(void)
{
    size_t len;
    char *buf;
    char *dot;

    /* Skip if set already */
    if (options[OID_O].value != NULL) {
        return;
    }

    len = strlen(in_fname);
    buf = malloc(len + 4);
    strcpy(buf, in_fname);

    /* Append extension after last '.' or at end */
    dot = strrchr(buf, '.');
    if (dot == NULL) {
        strcpy(buf + len, ".txt");
    } else {
        strcpy(buf + (dot - buf), ".txt");
    }

    options[OID_O].value = buf;
}

static void
parse_args(int argc, char **argv)
{
    struct option *opt;

    in_fname = NULL;
    for (int a = 1; a < argc; a++) {
        /* Set input filename */
        if (argv[a][0] != '-') {
            if (in_fname != NULL) {
                cmd_error("multiple input files specified\n");
            } else {
                in_fname = argv[a];
            }

            continue;
        }

        /* Identify option */
        opt = find_option(argv[a] + 1);
        if (opt == NULL) {
            cmd_error("unrecognized command-line option '%s'\n", argv[a]);
            continue;
        }

        /* Set option value */
        a++;
        if (a >= argc) {
            cmd_error("missing value after '%s'\n", argv[a - 1]);
        }
        opt->value = argv[a];
    }

    if (in_fname == NULL) {
        cmd_fatal("no input files\n");
    }

    set_out_fname();
}

static void
print_alias(struct type *typ)
{
    printf("alias (%lu bytes, %d pointer(s))", typ->size, typ->n_ptrs);
}

static void
print_enum(struct type *typ)
{
    struct enum_member *mem;

    printf("enum {\n");

    for (size_t r = 0; r < typ->members.n_rows; r++) {
        mem = (struct enum_member*)typ->members.rows[r].head;
        if (mem == (struct enum_member*)&typ->members.rows[r]) {
            continue;
        }

        do {
            printf("    %.*s,\n", (int)mem->name_len, mem->name);

            mem = (struct enum_member*)mem->hashmap_entry.list_entry.next;
        } while (mem != (struct enum_member*)&typ->members.rows[r]);
    }

    printf("}");
}

static void
print_struct(struct type *typ)
{
    struct struct_member *mem;

    printf("struct {\n");

    for (size_t r = 0; r < typ->members.n_rows; r++) {
        mem = (struct struct_member*)typ->members.rows[r].head;
        if (mem == (struct struct_member*)&typ->members.rows[r]) {
            continue;
        }

        do {
            printf("    %.*s %.*s; (%d pointer(s))\n", (int)mem->typ->name_len, mem->typ->name, (int)mem->name_len, mem->name, mem->n_ptrs);

            mem = (struct struct_member*)mem->hashmap_entry.list_entry.next;
        } while (mem != (struct struct_member*)&typ->members.rows[r]);
    }

    printf("}");
}

static void
print_type(struct type *typ)
{
    printf("type %.*s: ", (int)typ->name_len, typ->name);

    switch (typ->kind) {
    case TYK_ALIAS:
        print_alias(typ);
        break;
    case TYK_ENUM:
        print_enum(typ);
        break;
    case TYK_STRUCT:
        print_struct(typ);
        break;
    default:
        printf("(unknown)");
        break;
    }

    printf(";\n");

}

int
main(int argc, char **argv)
{
    char *input;
    struct parser parser;
    struct list *types_rows, *procs_rows;
    struct hashmap types, procs;
    struct type *typ;

    argv0 = argv[0];
    if (argc < 2) {
        cmd_fatal("no input files\n");
        exit(EXIT_FAILURE);
    }

    /* Parse command-line arguments */
    parse_args(argc, argv);

    /* Load input file */
    input = load_text_file(in_fname);
    if (input == NULL) {
        exit(EXIT_FAILURE);
    }

    /* Initialize hashmaps */
    types_rows = malloc(HASHMAP_ROWS * sizeof(struct list));
    types.rows = types_rows;
    types.n_rows = HASHMAP_ROWS;
    hashmap_init(&types);
    procs_rows = malloc(HASHMAP_ROWS * sizeof(struct list));
    procs.rows = procs_rows;
    procs.n_rows = HASHMAP_ROWS;
    hashmap_init(&procs);

    /* Parse input */
    parser.tok.fname = in_fname;
    parser.types = &types;
    parser.procs = &procs;
    parser_init(&parser, input);
    parser_parse(&parser);

    /* Print parsed types */
    for (size_t r = 0; r < types.n_rows; r++) {
        typ = (struct type*)types.rows[r].head;
        if (typ == (struct type*)&types.rows[r]) {
            continue;
        }

        do {
            print_type(typ);
            typ = (struct type*)typ->hashmap_entry.list_entry.next;
        } while (typ != (struct type*)&types.rows[r]);
    }

    free(procs_rows);
    free(types_rows);
    free(input);
    return 0;
}