/* meow_ui_media.c — App 侧媒体会话封装（SDK 公共件；见 meow_ui_media.h）。
 *
 * 传输：AF_UNIX SOCK_STREAM 到 MEOW_IPC_SOCK（缺省 /usr/data/meow_ipc.sock）。后台线程持有
 * 持久连接：HELLO(app_id, MF_PLAYBACK) 注册为媒体源 + poll 读 launcher 下发 MSG_PLAYCTL（经
 * 该连接 fd 回发，见 launcher meow_media.c send_playctl）。meow_ui_media_meta() 在调用线程
 * 直接经同一连接发 MSG_META（全双工：写 META、读 PLAYCTL 互不干扰）。
 *
 * 连接生命周期（best-effort）：懒连（首次 meta / 注册回调时 connect+HELLO+ACK）；
 * 断线（读失败/写失败）→ close+置 -1，下次 meta 重连；launcher 不在 → connect 失败 → 静默。
 * 线程安全：g_fd 读写经互斥；后台线程只在 poll/读失败时改 fd，meta 线程只在 connect 时改 fd。
 */
#include "meow_ui_media.h"
#include "meow_ipc.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <poll.h>
#include <pthread.h>
#include <sys/socket.h>
#include <sys/un.h>

static pthread_mutex_t g_mu   = PTHREAD_MUTEX_INITIALIZER;
static char            g_app[MEOW_APP_ID_MAX] = "";
static int             g_app_set = 0;
static int             g_fd   = -1;
static pthread_t       g_thr;
static int             g_thr_on = 0;
static volatile int    g_quit  = 0;
static meow_media_playctl_fn g_cb = NULL;
/* 本进程最后一次经 meow_ui_media_meta 上报的 state（0=停 1=播放 2=暂停 3=缓冲）。
 * 供「物理播放/暂停键」做切换判据：播放中→暂停(2)，否则→播放(1)。与 launcher
 * now_playing.c 的同款判定（state==PLAYING ? 2 : 1）对齐。 */
static int g_last_state = 0;
#define MEOW_UI_MEDIA_STATE_PLAYING 1

/* 后台线程主体（定义在文件后段；on_playctl 懒起时引用）。 */
static void *media_thread_main(void *arg);

static const char *sock_path(void)
{
    const char *e = getenv("MEOW_IPC_SOCK");
    return (e && e[0]) ? e : MEOW_IPC_PATH;
}

static int connect_path(const char *path)
{
    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (fd < 0) return -1;
    struct sockaddr_un a;
    memset(&a, 0, sizeof a);
    a.sun_family = AF_UNIX;
    strncpy(a.sun_path, path, sizeof a.sun_path - 1);
    if (connect(fd, (struct sockaddr *)&a, sizeof a) < 0) { close(fd); return -1; }
    return fd;
}

/* 写满 n 字节（EINTR 重试）；失败返回 0。 */
static int write_all(int fd, const uint8_t *p, size_t n)
{
    size_t off = 0;
    while (off < n) {
        ssize_t w = write(fd, p + off, n - off);
        if (w < 0) { if (errno == EINTR) continue; return 0; }
        if (w == 0) return 0;
        off += (size_t)w;
    }
    return 1;
}

static int read_all(int fd, uint8_t *p, size_t n)
{
    size_t off = 0;
    while (off < n) {
        ssize_t r = read(fd, p + off, n - off);
        if (r < 0) { if (errno == EINTR) continue; return 0; }
        if (r == 0) return 0;
        off += (size_t)r;
    }
    return 1;
}

/* 组装并写出 16B（LE）帧头 + 负载。 */
static int send_frame(int fd, uint16_t type, uint32_t req_id,
                      const void *payload, uint32_t len)
{
    uint8_t hdr[MEOW_IPC_HDR_LEN];
    uint32_t magic = MEOW_IPC_MAGIC;
    uint16_t ver   = MEOW_IPC_VERSION;
    memcpy(hdr + 0, &magic, 4);
    memcpy(hdr + 4, &ver, 2);
    memcpy(hdr + 6, &type, 2);
    memcpy(hdr + 8, &req_id, 4);
    memcpy(hdr + 12, &len, 4);
    if (!write_all(fd, hdr, sizeof hdr)) return -1;
    if (len && payload && !write_all(fd, payload, len)) return -1;
    return 0;
}

/* 读一帧头+负载；返回负载长（≥0），-1=断/坏帧。 */
static int read_frame(int fd, uint16_t *type, uint8_t *rbuf, uint32_t rcap)
{
    uint8_t hdr[MEOW_IPC_HDR_LEN];
    if (!read_all(fd, hdr, sizeof hdr)) return -1;
    uint32_t magic, len; uint16_t ver;
    memcpy(&magic, hdr, 4); memcpy(&ver, hdr + 4, 2); memcpy(type, hdr + 6, 2);
    memcpy(&len, hdr + 12, 4);
    if (magic != MEOW_IPC_MAGIC || ver != MEOW_IPC_VERSION) return -1;
    if (len > rcap) len = rcap;
    if (len > 0 && !read_all(fd, rbuf, len)) return -1;
    return (int)len;
}

static void media_app_id(void)
{
    if (g_app_set) return;
    const char *s = getenv("MEOW_LOG_APP");
    snprintf(g_app, sizeof g_app, "%s", (s && s[0]) ? s : "app");
    g_app_set = 1;
}

/* （调用方已持 mu）连接 + HELLO(MF_PLAYBACK) + 读 ACK。成功存 g_fd 返回 fd；失败 -1。 */
static int conn_locked(void)
{
    if (g_fd >= 0) return g_fd;
    int fd = connect_path(sock_path());
    if (fd < 0) return -1;
    media_app_id();
    m_hello_t h;
    memset(&h, 0, sizeof h);
    snprintf(h.app_id, sizeof h.app_id, "%s", g_app);
    h.version = 1;
    h.flags = MF_PLAYBACK;
    if (send_frame(fd, MSG_HELLO, 1, &h, sizeof h) != 0) { close(fd); return -1; }
    uint8_t rbuf[256];
    uint16_t rt;
    if (read_frame(fd, &rt, rbuf, sizeof rbuf) < 0 ||
        (rt != MSG_ACK && rt != MSG_ERR)) { close(fd); return -1; }
    g_fd = fd;
    return fd;
}

/* （调用方已持 mu）标记断线并关闭。 */
static void mark_dead_locked(void)
{
    if (g_fd >= 0) { close(g_fd); g_fd = -1; }
}

void meow_ui_media_init(const char *app_id)
{
    pthread_mutex_lock(&g_mu);
    if (app_id && app_id[0]) {
        snprintf(g_app, sizeof g_app, "%s", app_id);
        g_app_set = 1;
    } else if (!g_app_set) {
        const char *s = getenv("MEOW_LOG_APP");
        snprintf(g_app, sizeof g_app, "%s", (s && s[0]) ? s : "app");
        g_app_set = 1;
    }
    pthread_mutex_unlock(&g_mu);
}

void meow_ui_media_on_playctl(meow_media_playctl_fn cb)
{
    pthread_mutex_lock(&g_mu);
    g_cb = cb;
    int need_start = !g_thr_on;
    if (need_start) { g_quit = 0; g_thr_on = 1; }
    pthread_mutex_unlock(&g_mu);
    if (need_start) pthread_create(&g_thr, NULL, media_thread_main, NULL);
    /* detach：App 退出经 meow_ui_media_stop 设 g_quit 后线程自身退出，无需 join */
    if (need_start) pthread_detach(g_thr);
}

void meow_ui_media_meta(uint32_t state, uint32_t pos_ms, uint32_t dur_ms,
                        const char *title, const char *artist, const char *album,
                        const char *artwork, const char *lyric)
{
    m_meta_t mm;
    memset(&mm, 0, sizeof mm);
    pthread_mutex_lock(&g_mu);
    media_app_id();
    g_last_state = (int)state;   /* 记录最近上报 state：供物理播放/暂停键切换判据（见 sys_key） */
    snprintf(mm.app_id, sizeof mm.app_id, "%s", g_app);
    mm.state = state;
    mm.pos_ms = pos_ms;
    mm.dur_ms = dur_ms;
    if (title)  snprintf(mm.title,  sizeof mm.title,  "%s", title);
    if (artist) snprintf(mm.artist, sizeof mm.artist, "%s", artist);
    if (album)  snprintf(mm.album,  sizeof mm.album,  "%s", album);
    if (artwork && artwork[0]) { snprintf(mm.artwork, sizeof mm.artwork, "%s", artwork); mm.flags |= MF_ART | MF_COVER; }
    if (lyric && lyric[0])     { snprintf(mm.lyric,   sizeof mm.lyric,   "%s", lyric);   mm.flags |= MF_LYRIC; }

    int fd = conn_locked();
    if (fd >= 0) {
        if (send_frame(fd, MSG_META, (uint32_t)((uint64_t)pos_ms & 0x7FFFFFFF), &mm, sizeof mm) != 0) {
            mark_dead_locked();          /* 断线：下次 meta 重连 */
            fd = conn_locked();
            if (fd >= 0) (void)send_frame(fd, MSG_META, (uint32_t)((uint64_t)pos_ms & 0x7FFFFFFF), &mm, sizeof mm);
        }
    }
    pthread_mutex_unlock(&g_mu);
}

void meow_ui_media_stop(void)
{
    pthread_mutex_lock(&g_mu);
    g_quit = 1;
    mark_dead_locked();
    g_thr_on = 0;
    pthread_mutex_unlock(&g_mu);
}

/* ---- 物理媒体键 → 系统语义（M2.xx：SDK 输入层接管，App 前台也生效）----
 * 物理键是系统资源（APPS.md §3.4.1）：播放/暂停/上一曲/下一曲 → 转发到当前媒体会话。
 * 本进程注册过 playctl 回调（= 本 App 是媒体源）→ 直接本地回调（最简，无 IPC 往返）；
 * 否则经 IPC 发 MSG_PLAYCTL 给 launcher 转发到「最近活跃媒体会话」。best-effort 绝不崩。 */

/* 物理媒体键 keycode → MSG_PLAYCTL cmd（1=播放 2=暂停 3=上一首 4=下一首 5=seek）。
 * 播放/暂停(164)按最近上报 state 切换（播放中→暂停，否则→播放）；上一曲 165/19→3，下一曲 163→4。
 * 非媒体键返回 -1。last_state 由调用方在持锁下传入（读 g_last_state 快照）。 */
static int media_key_cmd(int code, int last_state)
{
    switch (code) {
        case 164:  /* KEY_PLAYPAUSE：切换（依最近上报 state） */
            return (last_state == MEOW_UI_MEDIA_STATE_PLAYING) ? 2 : 1;
        case 165:  case 19:   /* KEY_PREVIOUSSONG / 旧码 */
            return 3;
        case 163:              /* KEY_NEXTSONG */
            return 4;
        default:
            return -1;
    }
}

/* 控制器路径：发 MSG_PLAYCTL 给 launcher 转发到最近活跃媒体会话（launcher ipc_dispatch
 * MSG_PLAYCTL → meow_media_playctl → 下发到当前源 fd）。
 * 专门开一条临时连接（不复用媒体源持久连接 g_fd，避免与后台线程 poll/读竞争）；
 * 无 launcher/断线 → 静默降级（绝不崩）。 */
static void send_playctl_upstream(int cmd, int64_t seek_ms)
{
    int fd = connect_path(sock_path());
    if (fd < 0) return;
    m_playctl_t c;
    memset(&c, 0, sizeof c);
    c.cmd = (uint32_t)cmd;
    c.seek_ms = seek_ms;
    if (send_frame(fd, MSG_PLAYCTL, 1, &c, sizeof c) != 0) { close(fd); return; }
    /* 读 ACK（best-effort）：带 200ms poll，防 launcher 挂死导致输入线程阻塞。 */
    struct pollfd p;
    p.fd = fd; p.events = POLLIN; p.revents = 0;
    if (poll(&p, 1, 200) > 0 && (p.revents & POLLIN)) {
        uint8_t rbuf[128];
        uint16_t rt;
        (void)read_frame(fd, &rt, rbuf, sizeof rbuf);
    }
    close(fd);
}

/* 物理媒体键按下边沿（val==1 时由输入线程调用；重复/抬起不重复触发）。 */
void meow_ui_media_sys_key(int code)
{
    pthread_mutex_lock(&g_mu);
    meow_media_playctl_fn cb = g_cb;
    int cmd = media_key_cmd(code, g_last_state);
    pthread_mutex_unlock(&g_mu);
    if (cmd <= 0) return;
    if (cb) { cb(cmd, 0); return; }        /* 本 App 是媒体源（注册过回调）→ 本地回调 */
    send_playctl_upstream(cmd, 0);         /* 否则经 IPC 发 launcher 转发到最近活跃会话 */
}

/* 后台线程主体：懒连 + poll 读 launcher 下发 MSG_PLAYCTL → 调 cb。 */
static void *media_thread_main(void *arg)
{
    (void)arg;
    while (!g_quit) {
        pthread_mutex_lock(&g_mu);
        int fd = g_fd;
        if (fd < 0) fd = conn_locked();   /* 懒连/重连（best-effort；失败则回到循环再试） */
        pthread_mutex_unlock(&g_mu);
        if (fd < 0) { usleep(500000); continue; }

        struct pollfd p;
        p.fd = fd; p.events = POLLIN; p.revents = 0;
        int pr = poll(&p, 1, 200);
        if (pr < 0 && errno != EINTR) {
            pthread_mutex_lock(&g_mu); mark_dead_locked(); pthread_mutex_unlock(&g_mu);
            continue;
        }
        if (pr > 0 && (p.revents & (POLLHUP | POLLERR | POLLNVAL))) {
            pthread_mutex_lock(&g_mu); mark_dead_locked(); pthread_mutex_unlock(&g_mu);
            continue;
        }
        if (pr > 0 && (p.revents & POLLIN)) {
            uint8_t rbuf[MEOW_IPC_MAX];
            uint16_t type;
            int n = read_frame(fd, &type, rbuf, sizeof rbuf);
            if (n < 0) {
                pthread_mutex_lock(&g_mu); mark_dead_locked(); pthread_mutex_unlock(&g_mu);
                continue;
            }
            if (type == MSG_PLAYCTL && n >= (int)sizeof(m_playctl_t)) {
                m_playctl_t c;
                memcpy(&c, rbuf, sizeof c);
                /* g_cb 经互斥读快照后调用（App 回调可能在 UI 线程，简化为直接调） */
                pthread_mutex_lock(&g_mu);
                meow_media_playctl_fn cb = g_cb;
                pthread_mutex_unlock(&g_mu);
                if (cb) cb((int)c.cmd, (int64_t)c.seek_ms);
            }
        }
    }
    pthread_mutex_lock(&g_mu); mark_dead_locked(); pthread_mutex_unlock(&g_mu);
    return NULL;
}