/* ui/home.c — 我的歌单页（ACT_HOME，根页）。
 *
 * 内容区用 SDK 结构化列表（meow_listview，§5.5 W_LISTVIEW）虚拟化渲染
 * 「图标(folder 占位) + 歌单名 + 曲目数副标题 + 右侧箭头」。行数据源逐行填 meow_list_item；
 * 滚动/选中/命中由 SDK 收口。空态/错误/底部信息行用 meow_draw_custom_register 注册非控件绘制物。
 * 左缘返回 = 退出 App（app.c 处理）。下拉刷新可选：用 topbar 「↻」 动作项。
 */
#include "../ncm_app_internal.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

typedef struct { meow_view *view; int active; } home_ctrl;
static home_ctrl g_hc;

static meow_widget *g_tb;
static meow_widget *g_list;
static ncm_rect_t   r_cont, r_list;
static int          g_empty_id, g_footer_id;
static char         g_title[128];
static int          g_load_err;      /* 0=ok；负=错误码 */
static int          g_press_row, g_press_delta, g_dragging, g_drag_last_y;

static void home_drag_reset(void)
{
    g_press_row = -1;
    g_press_delta = 0;
    g_dragging = 0;
    g_drag_last_y = 0;
}

static int home_src2(int idx, meow_list_item *out, void *ctx)
{
    (void)ctx;
    if (idx < 0 || idx >= g_st.playlist_count) return 0;
    ncm_playlist_t *pl = &g_st.playlists[idx];
    static char title[128];      /* 歌单名截断 */
    static char sub[64];
    snprintf(title, sizeof title, "%s", pl->name);
    snprintf(sub, sizeof sub, "%d tracks", pl->track_count);
    out->icon_kind = MEOW_LIST_ICON_FOLDER;
    out->title = title;
    out->subtitle = sub;
    out->right  = MEOW_LIST_RIGHT_ARROW;
    out->on = 0;
    out->enabled = 1;
    return 1;
}

static void home_draw_empty(void *ctx)
{
    (void)ctx;
    if (meow_ui_activity_active() != ACT_HOME) return;
    if (g_load_err == 0 && g_st.playlist_count != 0) return;
    if (g_st.logged_in == 0)
        ncm_draw_empty(r_list, "NOT SIGNED IN", "sign in first");
    else if (g_load_err == NCM_ERR_AUTH)
        ncm_draw_empty(r_list, "SESSION EXPIRED", "please sign in again");
    else if (g_load_err)
        ncm_draw_empty(r_list, "NETWORK ERROR", "pull to retry");
    else
        ncm_draw_empty(r_list, "NO PLAYLISTS", "nothing here yet");
}

static void home_draw_footer(void *ctx)
{
    (void)ctx;
    if (meow_ui_activity_active() != ACT_HOME) return;
    if (g_load_err != 0) return;
    char foot[96];
    if (g_st.playlist_count == 0)
        snprintf(foot, sizeof foot, "0 playlists");
    else
        snprintf(foot, sizeof foot, "%d playlists   %s", g_st.playlist_count,
                 g_st.nickname[0] ? g_st.nickname : "");
    ncm_draw_footer(r_cont, foot);
}

void home_reload(void)
{
    g_load_err = 0;
    int rc = 0;
    if (g_host_mock) {                       /* 宿主/测试：跳过网络，用预置数据 */
        rc = 0;
    } else if (!g_st.logged_in) rc = NCM_ERR_AUTH;
    else rc = appstate_load_playlists();
    g_load_err = rc;
    if (g_load_err != 0) g_st.playlist_count = 0;
    if (g_list) {
        meow_listview_set_count(g_list, g_st.playlist_count);
        meow_listview_set_scroll(g_list, 0);
        meow_listview_set_sel(g_list, -1);
    }
    const char *name = g_st.nickname[0] ? g_st.nickname : "My Playlists";
    snprintf(g_title, sizeof g_title, "%s", name);
    if (g_tb) meow_topappbar_set_title(g_tb, g_title);
    const meow_theme *th = meow_theme_get();
    meow_ui_set_page_bg(th->bg);
    meow_ui_paint_full();
}

int home_is_active(void) { return g_hc.active; }

int home_on_tap(int x, int y)
{
    if (g_tb) {
        int ah = meow_topappbar_hit(g_tb, x, y);
        if (ah == MEOW_TOPBAR_BACK) { home_drag_reset(); return 1; }
        if (ah >= 0) { home_drag_reset(); home_reload(); return 1; }   /* ↻ 刷新 */
    }
    if (g_load_err != 0 || g_st.playlist_count == 0) return 0;
    if (meow_widget_hit(g_list, x, y)) {
        int row = meow_listview_hit(g_list, x, y);
        if (row < 0) { home_drag_reset(); return 1; }
        home_drag_reset();
        playlist_open(row);
        return 1;
    }
    return 0;
}

void home_touch_down(int x, int y)
{
    home_drag_reset();
    if (g_load_err != 0 || g_st.playlist_count == 0) return;
    if (meow_widget_hit(g_list, x, y)) {
        int row = meow_listview_hit(g_list, x, y);
        if (row >= 0) {
            g_press_row = row;
            meow_listview_set_sel(g_list, row);
        }
        g_dragging = 1;
        g_drag_last_y = y;
        meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h);
    }
}

void home_touch_move(int x, int y)
{
    (void)x;
    if (!g_dragging) return;
    if (g_press_row >= 0) {
        int d = y - g_drag_last_y; if (d < 0) d = -d;
        g_press_delta += d;
        if (g_press_delta > 10) { g_press_row = -1; meow_listview_set_sel(g_list, -1); }
    }
    int dy = y - g_drag_last_y; g_drag_last_y = y;
    if (dy == 0) return;
    int before = meow_listview_scroll(g_list);
    meow_listview_scroll_by(g_list, -dy);
    if (meow_listview_scroll(g_list) != before)
        meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h);
}

void home_swipe(int dir, int dist)
{
    if (dir != MEOW_SWIPE_UP && dir != MEOW_SWIPE_DOWN) return;
    if (g_load_err != 0 || g_st.playlist_count == 0) return;
    int del = (dir == MEOW_SWIPE_UP) ? dist : -dist;
    int before = meow_listview_scroll(g_list);
    meow_listview_scroll_by(g_list, del);
    if (meow_listview_scroll(g_list) != before)
        meow_ui_invalidate(r_list.x, r_list.y, r_list.w, r_list.h);
}

/* 生命周期 */
static void home_page_create(meow_view *v, void *ctx)
{
    (void)v;
    ((home_ctrl *)ctx)->view = v;
    r_cont = ncm_content_rect();
    r_list = NR(r_cont.x, r_cont.y, r_cont.w, r_cont.h - APP_FOOTER_H);
    if (r_list.h < 0) r_list.h = 0;
    meow_ui_activity_push(ACT_HOME);   /* 让下面控件 owner=ACT_HOME（§6.1 ①） */
    g_tb = ncm_topbar_create("My Playlists", 0, "\xe2\x86\xbb");   /* 无返回；右侧 ↻ */
    g_list = meow_listview_create(r_list.x, r_list.y, r_list.w, r_list.h, 0,
                                  home_src2, NULL, MEOW_LIST_SEL_SINGLE);
    meow_listview_set_item_h(g_list, APP_ROW_H);
    meow_ui_activity_pop();
    g_empty_id  = meow_draw_custom_register(1, r_list.x, r_list.y, r_list.w, r_list.h,
                                            home_draw_empty, NULL);
    g_footer_id = meow_draw_custom_register(1, r_cont.x, r_cont.y + r_cont.h - APP_FOOTER_H,
                                            r_cont.w, APP_FOOTER_H, home_draw_footer, NULL);
    home_drag_reset();
}

static void home_page_enter(meow_view *v, void *ctx)
{
    (void)v;
    ((home_ctrl *)ctx)->active = 1;
    const meow_theme *th = meow_theme_get();
    meow_ui_set_page_bg(th->bg);
    home_reload();
}

static void home_page_leave(meow_view *v, void *ctx)
{
    (void)v;
    ((home_ctrl *)ctx)->active = 0;
}

static void home_page_destroy(meow_view *v, void *ctx)
{
    (void)v; (void)ctx;
    if (g_empty_id)  { meow_draw_unregister(g_empty_id);  g_empty_id = 0; }
    if (g_footer_id) { meow_draw_unregister(g_footer_id); g_footer_id = 0; }
    if (g_list) { meow_widget_free(g_list); g_list = NULL; }
    if (g_tb)   { meow_widget_free(g_tb);   g_tb = NULL; }
}

meow_view *home_view_create(void)
{
    static const meow_view_hooks h = {
        .on_create  = home_page_create,
        .on_enter   = home_page_enter,
        .on_leave   = home_page_leave,
        .on_destroy = home_page_destroy,
    };
    return meow_view_create(ACT_HOME, MEOW_VIEW_ACTIVITY, &h, &g_hc);
}