/* mp_key.c — 远程控制域：按键注入（写 /dev/input/event* EV_KEY，物理键红线内）。 */
#include "mp.h"

#define PWR_KEYDEV   "/dev/input/event0"
#define ADC_KEYDEV   "/dev/input/event2"


int keycode_to_device(int code, const char **dev)
{
    switch (code) {
    case KEY_POWER:        *dev = PWR_KEYDEV; return KEY_POWER;
    case KEY_PREVIOUSSONG: *dev = PWR_KEYDEV; return KEY_PREVIOUSSONG;
    case KEY_VOLUMEUP:     *dev = ADC_KEYDEV; return KEY_VOLUMEUP;
    case KEY_VOLUMEDOWN:   *dev = ADC_KEYDEV; return KEY_VOLUMEDOWN;
    case KEY_NEXTSONG:     *dev = ADC_KEYDEV; return KEY_NEXTSONG;
    case KEY_PLAYPAUSE:    *dev = ADC_KEYDEV; return KEY_PLAYPAUSE;
    default:               return -1;
    }
}

int inject_key_event(const char *dev, int code, int down)
{
    int fd = open(dev, O_WRONLY | O_NONBLOCK);
    if (fd < 0) return -1;
    struct input_event ev;
    memset(&ev, 0, sizeof ev);
    ev.type = EV_KEY;
    ev.code = code;
    ev.value = down ? 1 : 0;
    int ok = (write(fd, &ev, sizeof ev) == (ssize_t)sizeof ev);
    if (ok) {
        memset(&ev, 0, sizeof ev);
        ev.type = EV_SYN;
        ev.code = SYN_REPORT;
        ev.value = 0;
        ok = (write(fd, &ev, sizeof ev) == (ssize_t)sizeof ev);
    }
    close(fd);
    return ok ? 0 : -1;
}

int inject_key_release(int code, int press_ms)
{
    const char *dev = NULL;
    int kc = keycode_to_device(code, &dev);
    if (kc < 0) return -1;
    int release_ms = press_ms > 0 ? press_ms : 0;
    if (inject_key_event(dev, code, 1) < 0) return -1;
    if (release_ms > 0) usleep((useconds_t)release_ms * 1000);
    else usleep(80 * 1000);
    if (inject_key_event(dev, code, 0) < 0) return -1;
    return 0;
}

int api_key_single(int sock, int code, const req_t *r)
{
    int press_ms = 0;
    char pressbuf[16] = "tap";
    const char *press = pressbuf;
    if (r->body && r->body[0]) {
        jv_t *root = jv_parse(r->body, (int)r->body_len);
        if (root) {
            jv_t *p = jv_obj_get(root, "press");
            if (p && p->type == J_STR) snprintf(pressbuf, sizeof pressbuf, "%s", p->str);
            jv_t *m = jv_obj_get(root, "ms");
            if (m && m->type == J_NUM) press_ms = (int)m->inum;
            jv_free(root);
        }
    }
    if (!strcmp(press, "hold"))
        return send_err(sock, 501, "NOT_IMPLEMENTED", "hold 持续注入需常驻通道（阶段 D），后端未实现");
    if (strcmp(press, "tap") && strcmp(press, "long"))
        return send_err(sock, 400, "BAD_REQUEST", "press 非法");
    if (press_ms <= 0) {
        if (!strcmp(press, "long")) press_ms = 3000;
    }
    /* 物理键红线：禁止映射 返回(158)/主页(172)/确认/exit（APPS.md）。 */
    if (code == 158 || code == 172 || code == 32 || code == 28 || code == 96)
        return send_err(sock, 403, "FORBIDDEN", "该键码（返回/主页/确认）按物理键红线禁止映射");
    const char *tmpdev = NULL;
    int dispatchable = (keycode_to_device(code, &tmpdev) >= 0);
    if (!dispatchable)
        return send_err(sock, 422, "UNSUPPORTED", "不支持的键码（仅音量/电源/播放/上下曲）");
    if (inject_key_release(code, press_ms) < 0)
        return send_err(sock, 500, "INTERNAL", "按键注入失败（无法打开输入设备）");
    sbuf_t s = {0};
    sA(&s, "{\"code\":%d,\"press\":\"%s\",\"dispatched\":true}", code, press);
    int ret = send_json(sock, 200, s.b ? s.b : "");
    sbuf_free(&s);
    return ret;
}

int api_key_batch(int sock, const req_t *r)
{
    if (!r->body || !r->body[0]) return send_err(sock, 400, "BAD_REQUEST", "缺少 body");
    jv_t *root = jv_parse(r->body, (int)r->body_len);
    if (!root) return send_err(sock, 400, "BAD_REQUEST", "body 非合法 JSON");
    jv_t *keys = jv_obj_get(root, "keys");
    if (!keys || keys->type != J_ARR) { jv_free(root); return send_err(sock, 400, "BAD_REQUEST", "缺 keys 数组"); }
    sbuf_t s = {0};
    int first = 1;
    for (const jv_t *k = keys->child; k; k = k->next) {
        if (k->type != J_OBJ) continue;
        jv_t *c = jv_obj_get(k, "code");
        jv_t *p = jv_obj_get(k, "press");
        jv_t *m = jv_obj_get(k, "ms");
        if (!c || c->type != J_NUM) continue;
        int code = (int)c->inum;
        if (code == 158 || code == 172) continue;   /* 红线跳过 */
        int press_ms = (m && m->type == J_NUM) ? (int)m->inum : 0;
        if (p && p->type == J_STR && !strcmp(p->str, "long") && press_ms <= 0) press_ms = 3000;
        const char *tmpdev = NULL;
        if (keycode_to_device(code, &tmpdev) < 0) continue;
        if (inject_key_release(code, press_ms) < 0) continue;
        if (!first) sA(&s, ",");
        first = 0;
        sA(&s, "%d", code);
    }
    jv_free(root);
    sbuf_t o = {0};
    if (first) sA(&o, "{\"dispatched\":[]}");
    else sA(&o, "{\"dispatched\":[%s]}", s.b);
    int ret = send_json(sock, 200, o.b ? o.b : "");
    sbuf_free(&s); sbuf_free(&o);
    return ret;
}