"""按「角色」切负载：replace（只负责替换）/ restore（只负责还原）。

拆盘的要点：一个 .face 只装一份负载，体积减半。
  * replace 盘：pay = q63 的帧（新字节）；rb = **原厂字节前 64 B 的指纹**（只用于版本校验）
  * restore 盘：pay = 原厂字节；      rb = **新字节前 64 B 的指纹**
指纹表让「写入前版本校验 + 写入后回读比对」两道保险都还在，代价只有 117*64 ≈ 7.5 KB。
两份盘用同一个 watchface id，装其中一份就会顶掉另一份，设备上始终只占一份空间。

产出：
  <out>/payload[_restore]/       NNN_<name>.bin + payload.lua
  <out>/blob_<role>/payload.bin  单条目：魔数 + 顺序拼接
  <out>/blob_<role>/fp.bin       指纹单条目
  <out>/flash.sh | restore.sh    线性 nsh 脚本（replace 盘还有 restore.sh 的对应物）
  <out>/payload.json             机器可读清单
"""
import os, sys, json, hashlib
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from paths import PROJ, INPUTS, WORK

ROLE = (sys.argv[1] if len(sys.argv) > 1 else 'replace').lower()
assert ROLE in ('replace', 'restore'), ROLE
STOCK = os.path.join(INPUTS, 'target', 'vela_app.bin')
PATCHED = os.path.join(WORK, 'anim', 'vela_app_anim.bin')
OUT = PROJ

recs_in = json.load(open(os.path.join(WORK, 'anim', 'manifest.json'), encoding='utf-8'))
stock = open(STOCK, 'rb').read()
patched = open(PATCHED, 'rb').read()
assert len(stock) == len(patched)

SRC = patched if ROLE == 'replace' else stock       # 要写进设备的字节
OTHER = stock if ROLE == 'replace' else patched     # 另一侧的字节（做指纹）
FPDIR = os.path.join(OUT, 'payload' if ROLE == 'replace' else 'payload_restore')
BLOBDIR = os.path.join(OUT, 'blob_' + ROLE)
FP_LEN = 64

# 不再往偏移 0 写那 32 字节的「canary」：写 superblock 头没有意义，
# 而且它极可能就是真机上「总是失败 1」的那一条（偏移 0 的写/读回最容易出岔子）。
assert stock[:8] == b'-rom1fs-'
records = []
for r in recs_in['records']:
    off, ln = r['offset'], r['length']
    records.append(dict(name=r['name'], offset=off, length=ln, data=SRC[off:off + ln],
                        changed=(stock[off:off + ln] != patched[off:off + ln]) if ROLE == 'replace' else True,
                        fp=OTHER[off:off + FP_LEN]))
emitted = [r for r in records if r['changed']]
dropped = [r for r in records if not r['changed']]


def write_pack(d):
    os.makedirs(d, exist_ok=True)
    for f in os.listdir(d):
        os.remove(os.path.join(d, f))
    rows = []
    for i, r in enumerate(emitted):
        fn = '%03d_%s.bin' % (i, r['name'])
        open(os.path.join(d, fn), 'wb').write(r['data'])
        assert r['offset'] % 4 == 0, r['name']
        rows.append(dict(name=r['name'], file=fn, offset=r['offset'], length=r['length']))
    with open(os.path.join(d, 'payload.lua'), 'w', encoding='utf-8', newline='\n') as f:
        f.write('-- generated by tools/make_dd_payload.py (%s) -- do not hand-edit\n' % ROLE)
        f.write('-- dd: -if <this dir>/<file> -of /dev/app bs=4 seek=offset/4 count=length/4\n')
        f.write('return {\n')
        for r in rows:
            f.write('  { name = "%s", file = "%s", offset = %d, length = %d },\n'
                    % (r['name'], r['file'], r['offset'], r['length']))
        f.write('}\n')
    return rows


lua_rows = write_pack(FPDIR)

MAGIC_PAY = b'\x00S4P-PAYv1\x00\xa5\x5a\xc3\x3c'      # 15 B，必须全局唯一
MAGIC_FP = b'\x00S4P-FPv1\x00\x5a\xa5\x3c\xc3'
os.makedirs(BLOBDIR, exist_ok=True)
for f in os.listdir(BLOBDIR):
    os.remove(os.path.join(BLOBDIR, f))
pay_blob = MAGIC_PAY + b''.join(r['data'] for r in emitted)
fp_blob = MAGIC_FP + b''.join(r['fp'] for r in emitted)
open(os.path.join(BLOBDIR, 'payload.bin'), 'wb').write(pay_blob)
open(os.path.join(BLOBDIR, 'fp.bin'), 'wb').write(fp_blob)
rel, off, fpoff = [], 0, 0
for r in emitted:
    rel.append(dict(name=r['name'], rel=off, fprel=fpoff, target=r['offset'],
                    length=r['length'], fplen=len(r['fp'])))
    off += r['length']
    fpoff += len(r['fp'])
assert fpoff == len(fp_blob) - len(MAGIC_FP), (fpoff, len(fp_blob))
json.dump(dict(role=ROLE, magic_len=len(MAGIC_PAY), magic_fp_len=len(MAGIC_FP), fp_len=FP_LEN,
               records=rel, pay_bytes=len(pay_blob), fp_bytes=len(fp_blob)),
          open(os.path.join(BLOBDIR, 'offsets.json'), 'w', encoding='utf-8'), indent=1)
print('blob_%s/ 单条目: payload.bin %d B + fp.bin %d B（%d 条记录）'
      % (ROLE, len(pay_blob), len(fp_blob), len(rel)))


def script(fname, rows, header, base, verify, tail):
    with open(os.path.join(OUT, fname), 'w', encoding='utf-8', newline='\n') as f:
        f.write('#!/bin/sh\n')
        for line in header:
            f.write('# ' + line + '\n')
        f.write('\nDEV=/dev/app\nBASE=' + base + '\n\n')
        f.write('echo "target check"\nls -l $DEV\n\n')
        for r in rows:
            b = 4 if (r['offset'] % 4 == 0 and r['length'] % 4 == 0) else 1
            f.write('echo "== ' + r['name'] + ' ==\n')
            f.write('dd if=$BASE/%s of=$DEV bs=%d seek=%d count=%d\n'
                    % (r['file'], b, r['offset'] // b, r['length'] // b))
            if verify:
                f.write('dd if=$DEV of=/tmp/chk.bin bs=%d skip=%d count=%d\n'
                        % (b, r['offset'] // b, r['length'] // b))
                f.write('cmp /tmp/chk.bin $BASE/%s\n\n' % r['file'])
        f.write(tail + '\n')


if ROLE == 'replace':
    script('flash.sh', lua_rows,
           ['S5 41mm 压力检测动画 -> S4 eSIM（只写负载）',
            '把 flash.sh 与 payload/ 放到同一个目录，例如 /data/s4panim/',
            '然后:  sh /data/s4panim/flash.sh     最后:  reboot',
            '还原用 restore.sh 或安装还原盘 S4PAnimRestore.face'],
           '/data/s4panim/payload', True,
           'rm /tmp/chk.bin\necho "all done - run reboot to apply"')
else:
    script('restore.sh', lua_rows,
           ['把 S4 eSIM 的压力检测动画写回原厂（还原盘）'],
           '/data/s4panim/payload_restore', True,
           'rm /tmp/chk.bin\necho "restore done - run reboot to apply"')

json.dump(dict(device='Xiaomi Watch S4 eSIM (o62lte)', target='/dev/app',
               role=ROLE, kind='pressure-measure-anim',
               dd='dd if=<dir>/<file> of=/dev/app bs=4 seek=<offset/4> count=<length/4>',
               block_size=4, records=lua_rows,
               dropped_identical=[r['name'] for r in dropped]),
          open(os.path.join(OUT, 'payload.json'), 'w', encoding='utf-8'), indent=1, ensure_ascii=False)
total = sum(r['length'] for r in lua_rows)
print('role=%s: emitted %d records, %.2f MB; dropped %d' % (ROLE, len(lua_rows), total / 1048576, len(dropped)))