/* open.c — handle lifecycle and the input batch API. vmctl_open dispatches to a
 * driver factory by cfg->driver; vmctl_close releases via ops.close. The batch
 * builders set vmctl_event.kind (the single event-kind code that drivers read),
 * and the single-event wrappers are thin batches of one. */

#include "driver.h"

#include <stdlib.h>
#include <string.h>

vmctl_t* vmctl_open(const vmctl_config* cfg) {
    if (!cfg) return NULL;
    switch (cfg->driver) {
    case VMCTL_DRIVER_QMP:    return vmctl_open_qmp_driver(cfg);
    case VMCTL_DRIVER_UINPUT: return vmctl_open_uinput_driver(cfg);
    default:                  return NULL;
    }
}

void vmctl_close(vmctl_t* v) {
    if (!v) return;
    v->ops.close(v);
    free(v);
}

/* ===== Batch builders ===== */

void vmctl_batch_init(vmctl_batch* b) {
    b->count = 0;
}

void vmctl_batch_abs(vmctl_batch* b, int axis, int value) {
    if (b->count >= VMCTL_BATCH_MAX) return;
    vmctl_event* e = &b->ev[b->count++];
    e->kind = VMCTL_EV_ABS; e->code = axis; e->value = value; e->scroll = 0.0;
}

void vmctl_batch_rel(vmctl_batch* b, int axis, int delta) {
    if (b->count >= VMCTL_BATCH_MAX) return;
    vmctl_event* e = &b->ev[b->count++];
    e->kind = VMCTL_EV_REL; e->code = axis; e->value = delta; e->scroll = 0.0;
}

void vmctl_batch_btn(vmctl_batch* b, int btn, int down) {
    if (b->count >= VMCTL_BATCH_MAX) return;
    vmctl_event* e = &b->ev[b->count++];
    e->kind = VMCTL_EV_BTN; e->code = btn; e->value = down; e->scroll = 0.0;
}

void vmctl_batch_key(vmctl_batch* b, int evdev_code, int down) {
    if (b->count >= VMCTL_BATCH_MAX) return;
    vmctl_event* e = &b->ev[b->count++];
    e->kind = VMCTL_EV_KEY; e->code = evdev_code; e->value = down; e->scroll = 0.0;
}

void vmctl_batch_scroll(vmctl_batch* b, int axis, double value) {
    if (b->count >= VMCTL_BATCH_MAX) return;
    vmctl_event* e = &b->ev[b->count++];
    e->kind = VMCTL_EV_SCROLL; e->code = axis; e->value = 0; e->scroll = value;
}

int vmctl_batch_send(vmctl_t* v, vmctl_batch* b) {
    if (b->count == 0) return 0;
    int rc = v->ops.send(v, b);
    if (rc != 0) return rc;   /* not sent = not recorded; never touch the receipt */

    /* Record the actuated key/btn down-bits (write-only; the send path above
     * never reads this map). abs/rel/scroll have no held state. */
    for (int i = 0; i < b->count; i++) {
        const vmctl_event* e = &b->ev[i];
        int down = e->value ? 1 : 0;
        switch (e->kind) {
        case VMCTL_EV_KEY: {
            int code = e->code;
            if (code < 0 || code > VMCTL_KEY_CODE_MAX) break;   /* out of range: ignore */
            unsigned char mask = (unsigned char)(1u << (code & 7));
            if (down) v->keys_held[code >> 3] |= mask;
            else      v->keys_held[code >> 3] &= (unsigned char)~mask;
            break;
        }
        case VMCTL_EV_BTN: {
            int btn = e->code;
            if (btn < 0 || btn >= 8) break;                     /* out of range: ignore */
            unsigned mask = 1u << btn;
            if (down) v->btns_held |= mask;
            else      v->btns_held &= ~mask;
            break;
        }
        default: break;   /* abs/rel/scroll: no-op for receipt */
        }
    }
    return rc;
}

/* ===== Single-event wrappers ===== */

int vmctl_abs(vmctl_t* v, int axis, int value) {
    vmctl_batch b;
    vmctl_batch_init(&b);
    vmctl_batch_abs(&b, axis, value);
    return vmctl_batch_send(v, &b);
}

int vmctl_rel(vmctl_t* v, int axis, int delta) {
    vmctl_batch b;
    vmctl_batch_init(&b);
    vmctl_batch_rel(&b, axis, delta);
    return vmctl_batch_send(v, &b);
}

int vmctl_btn(vmctl_t* v, int btn, int down) {
    vmctl_batch b;
    vmctl_batch_init(&b);
    vmctl_batch_btn(&b, btn, down);
    return vmctl_batch_send(v, &b);
}

int vmctl_key(vmctl_t* v, int evdev_code, int down) {
    vmctl_batch b;
    vmctl_batch_init(&b);
    vmctl_batch_key(&b, evdev_code, down);
    return vmctl_batch_send(v, &b);
}

int vmctl_scroll(vmctl_t* v, int axis, double value) {
    vmctl_batch b;
    vmctl_batch_init(&b);
    vmctl_batch_scroll(&b, axis, value);
    return vmctl_batch_send(v, &b);
}

/* ===== Held-state receipt (read-only) =====
 * Reads of the actuator's own last output; never mutate driver state. The
 * in-range predicate matches the write path in vmctl_batch_send. */

int vmctl_key_held(vmctl_t* v, int evdev_code) {
    if (!v || evdev_code < 0 || evdev_code > VMCTL_KEY_CODE_MAX) return 0;
    return (v->keys_held[evdev_code >> 3] >> (evdev_code & 7)) & 1;
}

int vmctl_btn_held(vmctl_t* v, int btn) {
    if (!v || btn < 0 || btn >= 8) return 0;
    return (int)((v->btns_held >> btn) & 1u);
}

int vmctl_keys_snapshot(vmctl_t* v, unsigned char* bits, size_t nbytes) {
    if (!v || !bits) return -1;
    size_t n = nbytes < VMCTL_KEYS_SNAPSHOT_BYTES ? nbytes : VMCTL_KEYS_SNAPSHOT_BYTES;
    memcpy(bits, v->keys_held, n);
    return (int)n;
}

unsigned vmctl_btns_snapshot(vmctl_t* v) {
    if (!v) return 0;
    return v->btns_held;
}

/* ===== uinput evdev export (UINPUT-only) ===== */

int vmctl_uinput_evdev(vmctl_t* v, char a[64], char b[64]) {
    if (!v || v->driver != VMCTL_DRIVER_UINPUT) return -1;
    int n = 0;
    if (a) { memcpy(a, v->ui_evdev_a, sizeof v->ui_evdev_a); if (a[0]) n++; }
    if (b) { memcpy(b, v->ui_evdev_b, sizeof v->ui_evdev_b); if (b[0]) n++; }
    return n;
}