// Space Taxi -- STL4 level file parser (plain stdio, no JoeyLib), shared
// by the game and the host-side simulation harness.
//
// Layout (all bytes, written by stuff/spacetaxi/romToLevel.py):
//   "STL4"
//   name[22]        $7D78    level name in screen codes
//   header[9]       $7D00    VIC colour block
//   padCount, specialPad, fuelRate
//   spawn[5]        $7D5B
//   templates[8]    $7D8F    Y accel, X accel, Y gravity, X gravity (LE words)
//   pads[10][8]     $7D0A    raw slots
//   screen[1000], color[1000]
//   levelIndex
//   spriteCount, then spriteCount x (ptr, 63 bytes)
//   hookData[616]   $7D98..$7FFF

#include <stdio.h>
#include <string.h>

#include "stSim.h"


static bool readBlock(FILE *fp, void *dst, size_t n);


static bool readBlock(FILE *fp, void *dst, size_t n) {
    return fread(dst, 1, n, fp) == n;
}


bool stLevelParse(StLevelT *out, FILE *fp) {
    uint8_t hdr[4];
    uint8_t counts[3];
    uint8_t templates[8];
    uint8_t slots[ST_MAX_PADS][8];
    uint8_t k;

    memset(out, 0, sizeof(*out));
    if (!readBlock(fp, hdr, 4u) || hdr[0] != 'S' || hdr[1] != 'T' || hdr[2] != 'L' || hdr[3] != '4') {
        return false;
    }
    if (!readBlock(fp, out->name, ST_LEVEL_NAME_CHARS)) {
        return false;
    }
    out->name[ST_LEVEL_NAME_CHARS] = 0u;
    if (!readBlock(fp, out->header, 9u) || !readBlock(fp, counts, 3u) || !readBlock(fp, out->spawn, 5u)) {
        return false;
    }
    out->padCount   = counts[0];
    out->specialPad = counts[1];
    out->fuelRate   = counts[2];
    if (!readBlock(fp, templates, 8u)) {
        return false;
    }
    out->accelY = (uint16_t)(templates[0] | ((uint16_t)templates[1] << 8));
    out->accelX = (uint16_t)(templates[2] | ((uint16_t)templates[3] << 8));
    out->gravY  = (uint16_t)(templates[4] | ((uint16_t)templates[5] << 8));
    out->gravX  = (uint16_t)(templates[6] | ((uint16_t)templates[7] << 8));
    if (!readBlock(fp, slots, sizeof(slots))) {
        return false;
    }
    for (k = 0u; k < ST_MAX_PADS; k++) {
        out->pads[k].x1Hi    = slots[k][0];
        out->pads[k].x1Lo    = slots[k][1];
        out->pads[k].x2Hi    = slots[k][2];
        out->pads[k].x2Lo    = slots[k][3];
        out->pads[k].row     = slots[k][4];
        out->pads[k].passMsb = slots[k][5];
        out->pads[k].passCol = slots[k][6];
        out->pads[k].unused  = slots[k][7];
    }
    if (!readBlock(fp, out->screen, ST_SCREEN_CELLS) || !readBlock(fp, out->color, ST_SCREEN_CELLS)) {
        return false;
    }
    if (!readBlock(fp, &out->levelIndex, 1u) || !readBlock(fp, &out->spriteCount, 1u)) {
        return false;
    }
    if (out->spriteCount > ST_MAX_LEVEL_SPRITES) {
        return false;
    }
    for (k = 0u; k < out->spriteCount; k++) {
        if (!readBlock(fp, &out->sprites[k].ptr, 1u) || !readBlock(fp, out->sprites[k].bitmap, ST_SPRITE_BYTES)) {
            return false;
        }
    }
    if (!readBlock(fp, out->hookData, ST_HOOK_BYTES)) {
        return false;
    }
    return true;
}