#include "assemble.h"
#include "eval.h"
#include "parse.h"
#include "resolve.h"
#include "str.h"
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static inline int define_labels(
    IdentResolver* resolver, PLabel* label, uint16_t asm_ip, Reporter* rep)
{
    if (label == NULL)
        return 0;
    int res = define_labels(resolver, label->next, asm_ip, rep);
    const IdentResol* existing = ident_resolver_resolve(resolver, label->ident);
    if (existing != NULL) {
        REPORTF_ERROR("redefinition of identifier '%s'", label->ident);
        reporter_print_loc(rep, label->loc);
        REPORTF_INFO("original definition of '%s'", label->ident);
        reporter_print_loc(rep, existing->loc);
        return 1;
    }
    if (label->sub_label) {
        ident_resolver_define_sublabel(
            resolver, asm_strdup(label->ident), label->loc, asm_ip);
    } else {
        ident_resolver_define_label(
            resolver, asm_strdup(label->ident), label->loc, asm_ip);
    }
    return res;
}

static inline void use_labels(IdentResolver* resolver, PLabel* label)
{
    if (label == NULL)
        return;
    use_labels(resolver, label->next);
    const IdentResol* existing = ident_resolver_resolve(resolver, label->ident);
    if (existing->ty == IdentResolTy_Label) {
        resolver->current_parent = existing;
    }
}

typedef struct {
    const char* input_file;
    const char* output_file;
} Args;

static inline Args parse_args(int argc, char** argv);

int main(int argc, char** argv)
{
    int res = 0;

    Args args = parse_args(argc, argv);

    FILE* input_fp = fopen(args.input_file, "r");
    if (!input_fp) {
        REPORTF_ERROR("could not open input file '%s': %s",
            args.input_file,
            strerror(errno));
        return -1;
    }
    fseek(input_fp, 0L, SEEK_END);
    size_t file_size = (size_t)ftell(input_fp);
    rewind(input_fp);

    char* input_text = calloc(file_size + 1, sizeof(char));
    size_t bytes_read = fread(input_text, sizeof(char), file_size, input_fp);
    fclose(input_fp);
    if (bytes_read != file_size) {
        REPORTF_ERROR("could not read input file '%s': %s",
            args.input_file,
            strerror(errno));
        return -1;
    }

    bool errors_occured = false;

    Parser parser;
    parser_construct(&parser, args.input_file, input_text);

    Reporter rep = {
        .filename = parser.lexer.filename,
        .text = parser.lexer.text,
        .text_len = parser.lexer.text_len,
    };

    size_t lines_capacity = 1024;
    PLine** lines = malloc(sizeof(PLine*) * lines_capacity);
    size_t lines_size = 0;

    while (!parser_done(&parser)) {
        if (lines_size + 1 > lines_capacity) {
            lines_capacity += 2;
            lines = realloc(lines, sizeof(PLine*) * lines_capacity);
        }
        PLine* line = parser_next(&parser);
        if (!line) {
            continue;
        }
        lines[lines_size++] = line;
    }

    errors_occured &= parser_error_occured(&parser);

    IdentResolver resolver;
    ident_resolver_construct(&resolver);

    OperandEvaluator evaluator = {
        .re = &resolver,
        .rep = &rep,
        .second_pass = false,
    };

    size_t chunk_capacity = 64;
    uint16_t* chunk = malloc(sizeof(uint16_t) * chunk_capacity);

    uint16_t ip = 0;
    for (size_t i = 0; i < lines_size; ++i) {
        int res = define_labels(&resolver, lines[i]->labels, ip, &rep);
        if (res != 0)
            errors_occured = true;
        uint16_t size = pline_assemble(&evaluator, chunk, lines[i], &rep);
        if (size == 0)
            errors_occured = true;
        ip += size;
    }

    if (errors_occured) {
        fprintf(stderr, "nothing written. stopping...\n");
        res = -1;
        goto leave_free_chunk;
    }

    evaluator.second_pass = true;

    FILE* output_fp = fopen(args.output_file, "wb");
    if (!output_fp) {
        REPORTF_ERROR("could not open output file '%s': %s",
            args.output_file,
            strerror(errno));
        res = -1;
        goto leave_free_chunk;
    }

    size_t total_bytes_written = 0;
    for (size_t i = 0; i < lines_size; ++i) {
        use_labels(&resolver, lines[i]->labels);

        size_t size = pline_assemble(&evaluator, chunk, lines[i], &rep);
        if (size == 0) {
            errors_occured = true;
        }

        if (errors_occured)
            continue;

        size_t bytes_written = fwrite(chunk, sizeof(uint16_t), size, output_fp);
        total_bytes_written += bytes_written;
        if (bytes_written != size) {
            REPORTF_ERROR("could not write to output file '%s': %s",
                args.output_file,
                strerror(errno));
            errors_occured = true;
        }
    }
    fclose(output_fp);

    if (errors_occured) {
        fprintf(
            stderr, "%ld bytes written. stopping...\n", total_bytes_written);
        res = -1;
        goto leave_free_chunk;
    }

    res = 0;
leave_free_chunk:
    free(chunk);
    // leave_free_lines:
    for (size_t i = 0; i < lines_size; ++i) {
        pline_free(lines[i]);
    }
    free(lines);
    free(input_text);
    ident_resolver_destroy(&resolver);
    return res;
}

static inline Args parse_args(int argc, char** argv)
{
    const char* input_file = NULL;
    const char* output_file = NULL;
    for (int i = 1; i < argc; ++i) {
        if (strcmp(argv[i], "-o") == 0) {
            i += 1;
            if (i >= argc) {
                REPORTF_ERROR("%s", "no filename given to -o");
                exit(1);
            }
            output_file = argv[i];
        } else {
            if (input_file != NULL) {
                REPORTF_ERROR("%s", "multiple input files specified");
                exit(1);
            }
            input_file = argv[i];
        }
    }
    if (input_file == NULL) {
        REPORTF_ERROR("%s", "no input file");
        exit(1);
    }
    if (output_file == NULL) {
        output_file = "out.o";
    }
    return (Args) {
        input_file,
        output_file,
    };
}