#include "scanner.h"
#include "parser.h"
#include "expr.h"
#include "interpreter.h"
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <string.h>
#include <errno.h>

void RunFile(const char*);
void RunPrompt(void);
char* GetFileContents(const char*);

int main(int argc, char** argv) {
    if (argc > 2) {
        printf("Useage: clox [script]\n");
        exit(EX_USAGE);
    } else if (argc == 2) {
        RunFile(argv[1]);
    } else {
        RunPrompt();
    }
}

void Print(TokenList* list) {
    for(int i = 0; i < list->size; i++) {
        if (list->tokens[i]->type == EndOF) {
            printf("[Line %d] EOF\n", list->tokens[i]->line);\
            return;
        }

        printf("[Line %d] %s\n", list->tokens[i]->line, list->tokens[i]->lexeme);
    }
}

void RunFile(const char* path) {
    printf("Running '%s'\n", path);
    char* contents = GetFileContents(path);
    TokenList* tokens = ScanTokens(contents);
    free(contents);
    Print(tokens);
    printf("TREE:\n");
    Expr* tree = GenerateExpressionTree(tokens);
    PrintExpressionTree(tree);
    printf("\n");
    Interpret(tree);
    FreeExpressionTree(tree);
    DestroyTokenList(tokens);
}

char* GetFileContents(const char* path) {
    FILE *script = fopen(path, "r");

    if (!script) {
        fprintf(stderr, "Failed to open script '%s'. %s.\n", path, strerror(errno));
        return NULL;
    }

    size_t length;
    char* content = NULL;

    size_t bytes_read = getdelim(&content, &length, '\0', script);

    fclose(script);

    if (bytes_read < 0) {
        fprintf(stderr, "Failed to read '%s'. %s.\n", path, strerror(errno));
        return NULL;
    }

    return content;
}

void RunPrompt(void) {
    printf("> ");
    char input[256];

    while(fgets(input, sizeof input, stdin) != NULL) {
        if (strcmp(input, "q\n") == 0) break;
        
        printf("E_NOT_IMPLEMENTED\n");

        printf("> ");
    }
}