/* logic/reader.c — 阅读方向状态（默认 RTL；M4/M6 的阅读器直接复用）+ 每册续读状态（M7）。
 *
 * M5 评审 P1 修复：方向设置要「下次启动生效」。最小持久化（不新增任何方向状态）：
 *   - mr_reader_set_direction 成功切换后 best-effort 写 meow_config("reader.dir","rtl"/"ltr")；
 *     写失败只打 WARN，不阻断切换（本次运行仍生效）；
 *   - mr_reader_get_direction 首次调用惰性读一次配置恢复；无配置/值非法 → 默认 RTL；
 *     之后走纯内存快路径（不再读配置）。
 * M7：阅读模式（翻页/条漫）与每册 last page 同为 meow_config 小键（reader.mode/page.<册标识>，
 *     册标识=规范化目录路径的 FNV-1a64）；书库行角标经 mr_cont_badge 读取同一份状态。
 * 依赖面：只 include 配置/日志两个模块头（不含 UI）；宿主测试用
 * test/settings_reader_stub.c 顶替 meow_config_* 与 meow_log。
 */
#include "reader.h"
#include "include/meow_ui_config.h"
#include "include/meow_ui_log.h"

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

#define MR_DIR_CFG_KEY "reader.dir"
#define MR_DIR_CFG_LTR "ltr"
#define MR_DIR_CFG_RTL "rtl"

static int g_direction = MR_DIR_RTL;
static int g_restored;      /* 0=尚未从配置恢复（首次 get/set 时读一次） */

static void reader_restore_once(void)
{
    char buf[8];

    if (g_restored) return;
    g_restored = 1;         /* 无配置也只读一次：之后纯内存 */
    if (meow_config_get(MR_DIR_CFG_KEY, buf, sizeof buf) != MEOW_CFG_OK) return;
    if (strcmp(buf, MR_DIR_CFG_LTR) == 0)      g_direction = MR_DIR_LTR;
    else if (strcmp(buf, MR_DIR_CFG_RTL) == 0) g_direction = MR_DIR_RTL;
    /* 其它值：忽略，保持默认 RTL */
}

int mr_reader_get_direction(void)
{
    reader_restore_once();
    return g_direction;
}

void mr_reader_set_direction(int dir)
{
    if (dir != MR_DIR_RTL && dir != MR_DIR_LTR) return;

    reader_restore_once();          /* 先恢复：避免「没 get 过就 set」把配置里的旧方向当默认值 */
    if (g_direction == dir) return; /* 无变化不写盘 */
    g_direction = dir;

    if (meow_config_set(MR_DIR_CFG_KEY, dir == MR_DIR_LTR ? MR_DIR_CFG_LTR : MR_DIR_CFG_RTL)
        != MEOW_CFG_OK)
        meow_log(MEOW_LOG_WARN, "reader.dir: save failed (best-effort, kept in memory)");
}

#ifdef MR_READER_TEST_HOOKS
void mr_reader_test_reset(void)
{
    g_direction = MR_DIR_RTL;
    g_restored = 0;
}
#endif

/* ============================================================ */
/* 阅读模式 + 每册续读状态（M7）                                 */
/* ============================================================ */
int mr_mode_valid(int mode)
{
    return mode == MR_MODE_PAGED || mode == MR_MODE_WEBTOON;
}

const char *mr_mode_name(int mode)
{
    return mode == MR_MODE_WEBTOON ? "webtoon" : "paged";
}

int mr_mode_parse(const char *s)
{
    if (!s) return -1;
    if (strcmp(s, "paged") == 0) return MR_MODE_PAGED;
    if (strcmp(s, "webtoon") == 0) return MR_MODE_WEBTOON;
    return -1;
}

/* 目录规范化：去掉末尾 '/'（根 "/" 保留），保证同一册跨调用/跨启动得到同一键。 */
static void cont_norm_dir(const char *dir, char *out, int outsz)
{
    if (!out || outsz <= 0) return;
    out[0] = '\0';
    if (!dir || !dir[0]) return;
    int n = (int)strlen(dir);
    while (n > 1 && dir[n - 1] == '/') n--;
    if (n >= outsz) n = outsz - 1;
    memcpy(out, dir, (size_t)n);
    out[n] = '\0';
}

static unsigned long long cont_fnv1a64(const char *s)
{
    unsigned long long h = 1469598103934665603ULL;
    for (const unsigned char *p = (const unsigned char *)s; *p; p++) {
        h ^= (unsigned long long)*p;
        h *= 1099511628211ULL;
    }
    return h;
}

int mr_cont_key(const char *dir, const char *field, char *out, int outsz)
{
    if (!out || outsz <= 0) return -1;
    out[0] = '\0';
    if (!dir || !dir[0] || !field || !field[0]) return -1;
    char norm[MR_CONT_PATH_MAX];
    cont_norm_dir(dir, norm, (int)sizeof norm);
    if (!norm[0]) return -1;
    int n = snprintf(out, (size_t)outsz, "reader.%s.%016llx", field, cont_fnv1a64(norm));
    if (n <= 0 || n >= outsz) { out[0] = '\0'; return -1; }
    return 0;
}

int mr_cont_get_page(const char *dir, int def)
{
    char key[64];
    char buf[24];
    if (mr_cont_key(dir, "page", key, (int)sizeof key) != 0) return def;
    if (meow_config_get(key, buf, (int)sizeof buf) != MEOW_CFG_OK) return def;
    char *end = NULL;
    long v = strtol(buf, &end, 10);
    if (end == buf || (end && *end != '\0')) return def;
    if (v < 0 || v > MR_CONT_PAGE_MAX) return def;
    return (int)v;
}

void mr_cont_set_page(const char *dir, int page)
{
    char key[64];
    char val[24];
    if (page < 0) page = 0;
    if (page > MR_CONT_PAGE_MAX) page = MR_CONT_PAGE_MAX;
    if (mr_cont_key(dir, "page", key, (int)sizeof key) != 0) return;
    snprintf(val, sizeof val, "%d", page);
    if (meow_config_set(key, val) != MEOW_CFG_OK)
        meow_log(MEOW_LOG_WARN, "reader: save page failed (best-effort)");
}

int mr_cont_get_mode(const char *dir, int def)
{
    char key[64];
    char buf[16];
    if (!mr_mode_valid(def)) def = MR_MODE_PAGED;
    if (mr_cont_key(dir, "mode", key, (int)sizeof key) != 0) return def;
    if (meow_config_get(key, buf, (int)sizeof buf) != MEOW_CFG_OK) return def;
    int m = mr_mode_parse(buf);
    return m >= 0 ? m : def;
}

void mr_cont_set_mode(const char *dir, int mode)
{
    char key[64];
    if (!mr_mode_valid(mode)) return;
    if (mr_cont_key(dir, "mode", key, (int)sizeof key) != 0) return;
    if (meow_config_set(key, mr_mode_name(mode)) != MEOW_CFG_OK)
        meow_log(MEOW_LOG_WARN, "reader: save mode failed (best-effort)");
}

void mr_cont_save(const char *dir, int page, int mode)
{
    if (!dir || !dir[0]) return;
    mr_cont_set_page(dir, page);
    mr_cont_set_mode(dir, mode);
}

int mr_cont_badge(const char *dir, char *out, int outsz)
{
    if (!out || outsz <= 0) return 0;
    out[0] = '\0';
    int page = mr_cont_get_page(dir, -1);
    if (page <= 0) return 0;
    snprintf(out, (size_t)outsz, "续读 P%d", page + 1);
    return 1;
}