#include <stdio.h>
#include <stdlib.h>
#include "vendor/mpc.h"
#include "hashmap.h"


struct post {
    char title[64];
    char tags[8][32];
};

char *read_file(char *filename) {
    char *input = malloc(BUFSIZ);
    unsigned int size = 0;

    FILE *f = fopen(filename, "r");
    if (!f) {
        printf("Could not open \"%s\" for reading", filename);
        exit(1);
    }

    unsigned int read = 0;
    while ( (read = fread(input, 1, BUFSIZ, f)) > 0) {
        size += read;
        input = realloc(input, size + BUFSIZ);
    }

    fclose(f);

    input[size] = '\0';
    return input;
}

int eval(char *dest, mpc_ast_t* t, struct hashmap *ctx) {
    printf("%s: %s\n", t->tag, t->contents);

    if (strstr(t->tag, "content|text")) {
        strcat(dest, t->contents);
        return 0;
    }

    if (strstr(t->tag, "content|var")) {
        printf("Key: %s\n", t->contents);
        char *value = hashmap_get(ctx, t->children[1]->contents);
        if  (value == NULL) {
            return 1;
        }
        strcat(dest, value);
        return 0;
    }

    if (strstr(t->tag, "content|for")) {
        char *tmp_key = t->children[2]->contents;
        char *iterator_key = t->children[4]->contents;
        // TODO: Make this dynamic
        struct post **posts = hashmap_get(ctx, iterator_key);
        for (int i=0; i < 2; i++) {
            hashmap_insert(ctx, tmp_key, posts[i]);
            eval(dest, t->children[6], ctx);
        }
        return 0;
    }

    for (int i=0; i < t->children_num; i++) {
        eval(dest, t->children[i], ctx);
    }
    
    return 0;
}

mpc_parser_t *parser_init() {
    mpc_parser_t *Symbol = mpc_new("symbol");
    mpc_parser_t *Text = mpc_new("text");
    mpc_parser_t *Var_Open = mpc_new("var_open");
    mpc_parser_t *Var_Close = mpc_new("var_close");
    mpc_parser_t *Var = mpc_new("var");
    mpc_parser_t *Block_Open = mpc_new("block_open");
    mpc_parser_t *Block_Close = mpc_new("block_close");
    mpc_parser_t *For = mpc_new("for");
    mpc_parser_t *Content = mpc_new("content");
    mpc_parser_t *Template = mpc_new("template");
    mpca_lang(MPCA_LANG_WHITESPACE_SENSITIVE,
    " symbol    : /[a-zA-Z._]+/ ;"
    " var_open  : /\{{2} ?/ ;"
    " var_close : / ?}{2}/ ;"
    " var       : <var_open> <symbol> <var_close> ;"
    " block_open: /\{\% ?/ ;"
    " block_close: / ?\%}/ ;"
    " for       : <block_open> \"for \" <symbol> \" in \" <symbol> <block_close> <content>* <block_open> \"endfor\" <block_close> ;"
    " text      : /[^{][^{%]*/ ;"
    " content   : <var> | <for> | <text>;"
    " template  : /^/ <content>* /$/ ;",
    Symbol, Var_Open, Var_Close, Var, Block_Open, Block_Close, For, Text, Content, Template, NULL);
    return Template;
}

void template(char *tmpl, struct hashmap *ctx) {
    mpc_parser_t *parser = parser_init();
    mpc_result_t r;

    if (mpc_parse("input", tmpl, parser, &r)) {
        mpc_ast_print(r.output);
        
        // FIXME: Allocate precisely
        char *output = malloc(strlen(tmpl) * 2);
        output[0] = '\0';
        eval(output, r.output, ctx);
        printf("Template: \n%s", output);
        
        mpc_ast_delete(r.output);
        free(output);
    } else {
        mpc_err_print(r.error);
        mpc_err_delete(r.error);
    }
}


int main() {
    char *input = read_file("index.tpl");

    struct hashmap *ctx = hashmap_new();
    hashmap_insert(ctx, "title", "Hello world");

    struct post home = { 
        .title = "Homepage",
        .tags = {
            "Tag 1", "Tag 2"
        }
    };
    hashmap_insert(ctx, "home", &home);

    struct post posts[] = {
        { .title = "Post 1", .tags = { "p1t1" } },
        { .title = "Post 2", .tags = { "p2t1" } },
    };
    hashmap_insert(ctx, "posts", &posts);

    template(input, ctx);
    hashmap_free(ctx);
    free(input);
}