/* app/progress.c — 进度持久化（实现见 app/progress.h）。 */
#include "progress.h"
#include "meow_ui.h"        /* meow_config_dir() */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>

/* 从 MEOW_DATA_DIR（<TF>/MeowData/<pkg>/data）剥掉尾 "/data"，得到 <TF>/MeowData/<pkg>。 */
static void strip_data_suffix(const char *d, char *out, int outsz)
{
    if (!d || !d[0]) { strncpy(out, "/tmp", (size_t)outsz - 1); out[outsz - 1] = 0; return; }
    size_t n = strlen(d);
    const char *suffix = "/data";
    size_t sl = strlen(suffix);
    size_t keep;
    if (n >= sl && strcmp(d + n - sl, suffix) == 0) keep = n - sl;
    else keep = n;
    if (keep >= (size_t)outsz) keep = (size_t)outsz - 1;
    memcpy(out, d, keep);
    out[keep] = 0;
}

int rdprog_dir(char *out, int outsz)
{
    if (!out || outsz <= 0) return -1;
    const char *data = meow_config_dir();
    char base[360];
    strip_data_suffix(data ? data : "", base, sizeof base);
    if (snprintf(out, (size_t)outsz, "%s/progress", base) >= outsz) return -2;
    /* mkdir -p */
    char tmp[400];
    strncpy(tmp, out, sizeof tmp - 1); tmp[sizeof tmp - 1] = 0;
    for (char *p = tmp + 1; *p; p++) {
        if (*p == '/') { *p = 0; mkdir(tmp, 0755); *p = '/'; }
    }
    mkdir(tmp, 0755);
    return 0;
}

void rdprog_hash(const char *book_path, char *out, int outsz)
{
    uint32_t h = 2166136261u;
    for (const unsigned char *p = (const unsigned char *)book_path; *p; p++) {
        h ^= *p; h *= 16777619u;
    }
    snprintf(out, (size_t)outsz, "%08x.prog", h);
}

static int rdprog_path(const char *book_path, char *out, int outsz,
                       int *created_dir)
{
    char dir[400];
    if (rdprog_dir(dir, sizeof dir) != 0) return -1;
    char name[24];
    rdprog_hash(book_path, name, sizeof name);
    if (snprintf(out, (size_t)outsz, "%s/%s", dir, name) >= outsz) return -2;
    if (created_dir) *created_dir = 1;
    return 0;
}

int rdprog_load(const char *book_path, rdprog *p)
{
    if (!book_path || !p) return -1;
    char path[440];
    if (rdprog_path(book_path, path, sizeof path, NULL) != 0) return -1;
    FILE *f = fopen(path, "rb");
    if (!f) return 0;
    char line[256];
    int seg = 0, fs = 0, ls = 0; int32_t ch = 0; uint64_t ts = 0; int v = 0, found = 0;
    while (fgets(line, sizeof line, f)) {
        if (sscanf(line, "v=%d", &v) == 1) { if (v == 1) found = 1; }
        else if (sscanf(line, "seg=%d", &seg) == 1) { /* no-op */ }
        else if (sscanf(line, "ch=%d", &ch) == 1) { /* no-op */ }
        else if (sscanf(line, "fs=%d", &fs) == 1) { /* no-op */ }
        else if (sscanf(line, "ls=%d", &ls) == 1) { /* no-op */ }
        else if (sscanf(line, "ts=%llu", (unsigned long long *)&ts) == 1) { /* no-op */ }
    }
    fclose(f);
    if (!found) return 0;
    p->valid = 1; p->seg = seg; p->ch = ch; p->fs = fs; p->ls = ls; p->ts = ts;
    return 1;
}

int rdprog_save(const char *book_path, const rdprog *p)
{
    if (!book_path || !p) return -1;
    char path[440];
    if (rdprog_path(book_path, path, sizeof path, NULL) != 0) return -1;
    FILE *f = fopen(path, "wb");
    if (!f) return -1;
    /* 先写临时再改原子（exFAT 无 rename+replace 语义保证，直接写亦可接受） */
    fprintf(f, "v=1\n");
    fprintf(f, "seg=%d\n", p->seg);
    fprintf(f, "ch=%d\n", (int)p->ch);
    fprintf(f, "fs=%d\n", p->fs);
    fprintf(f, "ls=%d\n", p->ls);
    fprintf(f, "ts=%llu\n", (unsigned long long)p->ts);
    fclose(f);
    return 0;
}