/* 配网热点的平台无关部分。判据表与表单格式在 prov.h。 */
#include "prov.h"

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

#include "cmd.h"
#include "netcfg.h"

static bool     s_ap;
static bool     s_was_up;
static uint32_t s_since; /* STA 上一次「有地址 ↔ 没地址」翻转的时刻（启动算一次） */
static bool     s_aged;  /* 翻转之后已经过了门限（过了就锁住：32 位时钟 49.7 天回绕，放着不管会「变年轻」） */
static bool     s_touch; /* hold 窗口还开着（过期即清，同上） */
static uint32_t s_touch_at;
static int      s_prev_sta;

void prov_init(uint32_t now)
{
    s_ap = false;
    s_was_up = false;
    s_since = now;
    s_aged = false;
    s_touch = false;
    s_touch_at = now;
    s_prev_sta = 0;
}

prov_out_t prov_step(const prov_in_t *in, uint32_t now)
{
    if (in->wifi_up != s_was_up) {
        s_was_up = in->wifi_up;
        s_since = now;
        s_aged = false;
    }
    if (!s_aged && (uint32_t)(now - s_since) >= (in->wifi_up ? PROV_LINGER_MS : PROV_FAIL_MS)) {
        s_aged = true;
    }
    if (in->touched || in->ap_sta > s_prev_sta) { /* 有人刚连上热点也算一次 */
        s_touch = true;
        s_touch_at = now;
    }
    s_prev_sta = in->ap_sta;
    if (s_touch && (uint32_t)(now - s_touch_at) >= PROV_HOLD_MS) {
        s_touch = false;
    }

    prov_out_t o = { .ap = false, .hold = false, .why = PROV_WHY_OFF };
    if (in->wifi_up) {
        if (s_ap && in->ap_sta > 0 && !s_aged) {
            o.ap = true;
            o.why = PROV_WHY_LINGER;
        }
    } else if (in->n_wifi <= 0) {
        o.ap = true;
        o.why = PROV_WHY_NOCFG;
    } else if (s_aged || s_ap) {
        /* `|| s_ap`：开着就不因为「刚配了一组、还没满 60 s」而关掉 —— 那正是人在网页上点完保存的那一刻。 */
        o.ap = true;
        o.why = PROV_WHY_FAIL;
    }
    o.hold = o.ap && !in->wifi_up && in->ap_sta > 0 && s_touch;
    s_ap = o.ap;
    return o;
}

const char *prov_why_str(prov_why_t w)
{
    switch (w) {
    case PROV_WHY_OFF:    return "off";
    case PROV_WHY_NOCFG:  return "nocfg";
    case PROV_WHY_FAIL:   return "fail";
    case PROV_WHY_LINGER: return "linger";
    }
    return "?";
}

/* ---- 名字与口令 ------------------------------------------------------------ */

void prov_ssid(const char *id, char out[PROV_SSID_MAX])
{
    const size_t n = strlen(id);
    snprintf(out, PROV_SSID_MAX, "PhoneRail-%s", n > 6 ? id + n - 6 : id);
}

/* ---- 表单 → 命令行 --------------------------------------------------------- */

#define FIELD_MAX 64 /* = CMD_JSON_STR_MAX − 1：再长解析器也不收 */
#define FIELDS    5

/* 把正文按 \n 切成至多 FIELDS 段（行尾的 \r 去掉），拷进 f[]。返回段数；−1 = 太长 / 段太多，−2 = 有坏字符。 */
static int split(const char *body, char f[FIELDS][FIELD_MAX + 1])
{
    int    n = 0;
    size_t len = 0;
    f[0][0] = '\0';
    for (const char *p = body;; p++) {
        if (*p == '\n' || *p == '\0') {
            if (len > 0 && f[n][len - 1] == '\r') {
                len--;
            }
            f[n][len] = '\0';
            for (size_t i = 0; i < len; i++) {
                const unsigned char c = (unsigned char)f[n][i];
                if (c < 0x20 || c == 0x7F || c == '"' || c == '\\') {
                    return -2;
                }
            }
            n++;
            if (*p == '\0') {
                return n;
            }
            if (n >= FIELDS) {
                return -1;
            }
            len = 0;
            continue;
        }
        if (len >= FIELD_MAX) {
            return -1;
        }
        f[n][len++] = *p;
    }
}

size_t prov_build_line(const char *body, uint32_t seq, char *out, size_t cap, const char **err)
{
    static const char *dummy;
    if (err == NULL) {
        err = &dummy;
    }
    *err = "bad_form";
    if (body == NULL || out == NULL || cap == 0 || seq == 0) {
        return 0;
    }
    char      f[FIELDS][FIELD_MAX + 1];
    const int n = split(body, f);
    if (n < 0) {
        *err = (n == -2) ? "bad_char" : "too_long";
        return 0;
    }
    for (int i = n; i < FIELDS; i++) {
        f[i][0] = '\0';
    }
    int w;
    if (strcmp(f[0], "wifi") == 0 && n >= 2 && n <= 3 && f[1][0] != '\0') {
        w = snprintf(out, cap, "{\"seq\":%lu,\"cmd\":\"wifi\",\"ssid\":\"%s\",\"pass\":\"%s\"}",
                     (unsigned long)seq, f[1], f[2]);
    } else if (strcmp(f[0], "del") == 0 && n == 2 && f[1][0] != '\0') {
        w = snprintf(out, cap, "{\"seq\":%lu,\"cmd\":\"wifi\",\"ssid\":\"%s\",\"del\":true}",
                     (unsigned long)seq, f[1]);
    } else if (strcmp(f[0], "mqtt") == 0 && n >= 2 && f[1][0] != '\0') {
        unsigned long tele = 0;
        for (const char *p = f[4]; *p != '\0'; p++) {
            if (*p < '0' || *p > '9' || tele > NETCFG_TELE_MAX_MS) {
                return 0;
            }
            tele = tele * 10u + (unsigned long)(*p - '0');
        }
        /* 口令留空 = 沿用已存的那份：网页上看不到旧口令（永不回显），不该逼人每次重输。 */
        if (f[3][0] == '\0') {
            w = snprintf(out, cap,
                         "{\"seq\":%lu,\"cmd\":\"mqtt\",\"uri\":\"%s\",\"user\":\"%s\",\"keep_pass\":true,"
                         "\"tele_ms\":%lu}",
                         (unsigned long)seq, f[1], f[2], tele);
        } else {
            w = snprintf(out, cap,
                         "{\"seq\":%lu,\"cmd\":\"mqtt\",\"uri\":\"%s\",\"user\":\"%s\",\"pass\":\"%s\","
                         "\"tele_ms\":%lu}",
                         (unsigned long)seq, f[1], f[2], f[3], tele);
        }
    } else {
        return 0;
    }
    if (w <= 0 || (size_t)w >= cap || w >= CMD_LINE_MAX) {
        *err = "too_long";
        out[0] = '\0';
        return 0;
    }
    *err = NULL;
    return (size_t)w;
}

size_t prov_json_esc(const char *s, char *out, size_t cap)
{
    size_t n = 0;
    for (; *s != '\0'; s++) {
        const unsigned char c = (unsigned char)*s;
        const bool          esc = c < 0x20 || c == 0x7F || c == '"' || c == '\\';
        if (n + (esc ? 6u : 1u) >= cap) {
            if (cap > 0) {
                out[0] = '\0';
            }
            return 0;
        }
        if (esc) {
            n += (size_t)snprintf(out + n, cap - n, "\\u%04x", (unsigned)c);
        } else {
            out[n++] = (char)c;
        }
    }
    if (cap > 0) {
        out[n] = '\0';
    }
    return n;
}