#include <stdlib.h>
#include <stdio.h>

#include "lex.h"
#include "typeutils.h"
#include "parse.h"
DECLARE_VEC(char*, StrVec)


typedef struct {
    Token* ptr;
    size_t len;
    size_t pos;
} TokStream;


Connector parse_connector(TokStream* toks) {
    Token tok = toks->ptr[toks->pos];
    if (tok.kind != TOK_SPECIAL) exit(67);
    switch (tok.as.spec) {
        case PIPE: return CONN_PIPE;
        case EOL: return CONN_EOL;
        default: exit(76);
    }
}


Command parse_command(TokStream* toks) {
    TokenVec args = make_TokenVec(256);
    RedirectVec redirects = make_RedirectVec(256);
    for (
        Token curr_tok; 
        (curr_tok = toks->ptr[toks->pos], !(curr_tok.kind == TOK_SPECIAL && (curr_tok.as.spec == PIPE || curr_tok.as.spec == EOL)));
        toks->pos++
    ) {
        switch (curr_tok.kind) {
            case TOK_SPECIAL: 
                Token tok;
                switch (curr_tok.as.spec) {
                    case WRITE_REDIR_TRUNC:
                        toks->pos++;
                        tok = toks->ptr[toks->pos];
                        if(tok.kind != TOK_WORD) exit(1);
                        push_to_RedirectVec(&redirects, (Redirect){.kind = STDOUT_REDIR_TRUNC, .as.std_redir_filename = tok.as.word});
                        break;
                    case WRITE_REDIR_APPEND:
                        toks->pos++;
                        tok = toks->ptr[toks->pos];
                        if(tok.kind != TOK_WORD) exit(1);
                        push_to_RedirectVec(&redirects, (Redirect){.kind = STDOUT_REDIR_APPEND, .as.std_redir_filename = tok.as.word});
                        break;
                    case READ_REDIR:
                        toks->pos++;
                        tok = toks->ptr[toks->pos];
                        if(tok.kind != TOK_WORD) exit(1);
                        push_to_RedirectVec(&redirects, (Redirect){.kind = STDOUT_REDIR_APPEND, .as.std_redir_filename = tok.as.word});
                        break;
                    default:
                        exit(69);
                }
                break;
            default: 
                push_to_TokenVec(&args, curr_tok);
        }
    }
    return (Command){.args = args, .redirects = redirects};
}


Pipeline parse_tokstream(TokenVec toks) {
    TokStream tokstream = {.ptr = toks.items, .len = toks.count, .pos = 0};
    Pipeline result = make_Pipeline(256);
    while (true) {
        Command cmd = parse_command(&tokstream);
        Connector conn = parse_connector(&tokstream);
        push_to_Pipeline(&result, (PipelineElement){.cmd = cmd, .conn = conn});
        if (conn == CONN_EOL) break;
    }
}