#!/usr/bin/env python3
# SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
# SPDX-License-Identifier: Apache-2.0
import sys
import struct
import subprocess
import re
import os
import os.path
import argparse
import json


UF2_MAGIC_START0 = 0x0A324655 # "UF2\n"
UF2_MAGIC_START1 = 0x9E5D5157 # Randomly selected
UF2_MAGIC_END    = 0x0AB16F30 # Ditto

INFO_FILE = '/INFO_UF2.TXT'

appstartaddr = 0x2000
familyid = 0x0


def is_uf2(buf):
    w = struct.unpack('<II', buf[0:8])
    return w[0] == UF2_MAGIC_START0 and w[1] == UF2_MAGIC_START1

def is_hex(buf):
    try:
        w = buf[0:30].decode('utf-8')
    except UnicodeDecodeError:
        return False
    if w[0] == ':' and re.match(b'^[:0-9a-fA-F\r\n]+$', buf):
        return True
    return False

def convert_from_uf2(buf):
    global appstartaddr
    global familyid
    numblocks = len(buf) // 512
    curraddr = None
    currfamilyid = None
    families_found = {}
    prev_flag = None
    all_flags_same = True
    outp = []
    for blockno in range(numblocks):
        ptr = blockno * 512
        block = buf[ptr:ptr + 512]
        hd = struct.unpack(b'<IIIIIIII', block[0:32])
        if hd[0] != UF2_MAGIC_START0 or hd[1] != UF2_MAGIC_START1:
            print('Skipping block at ' + ptr + '; bad magic')
            continue
        if hd[2] & 1:
            # NO-flash flag set; skip block
            continue
        datalen = hd[4]
        if datalen > 476:
            assert False, 'Invalid UF2 data size at ' + ptr
        newaddr = hd[3]
        if (hd[2] & 0x2000) and (currfamilyid == None):
            currfamilyid = hd[7]
        if curraddr == None or ((hd[2] & 0x2000) and hd[7] != currfamilyid):
            currfamilyid = hd[7]
            curraddr = newaddr
            if familyid == 0x0 or familyid == hd[7]:
                appstartaddr = newaddr
        padding = newaddr - curraddr
        if padding < 0:
            assert False, 'Block out of order at ' + ptr
        if padding > 10*1024*1024:
            assert False, 'More than 10M of padding needed at ' + ptr
        if padding % 4 != 0:
            assert False, 'Non-word padding size at ' + ptr
        while padding > 0:
            padding -= 4
            outp += b'\x00\x00\x00\x00'
        if familyid == 0x0 or ((hd[2] & 0x2000) and familyid == hd[7]):
            outp.append(block[32 : 32 + datalen])
        curraddr = newaddr + datalen
        if hd[2] & 0x2000:
            if hd[7] in families_found.keys():
                if families_found[hd[7]] > newaddr:
                    families_found[hd[7]] = newaddr
            else:
                families_found[hd[7]] = newaddr
        if prev_flag == None:
            prev_flag = hd[2]
        if prev_flag != hd[2]:
            all_flags_same = False
        if blockno == (numblocks - 1):
            print('--- UF2 File Header Info ---')
            families = load_families()
            for family_hex in families_found.keys():
                family_short_name = ''
                for name, value in families.items():
                    if value == family_hex:
                        family_short_name = name
                print('Family ID is {:s}, hex value is 0x{:08x}'.format(family_short_name,family_hex))
                print('Target Address is 0x{:08x}'.format(families_found[family_hex]))
            if all_flags_same:
                print('All block flag values consistent, 0x{:04x}'.format(hd[2]))
            else:
                print('Flags were not all the same')
            print('----------------------------')
            if len(families_found) > 1 and familyid == 0x0:
                outp = []
                appstartaddr = 0x0
    return b''.join(outp)

def convert_to_carray(file_content):
    outp = 'const unsigned long bindata_len = %d;\n' % len(file_content)
    outp += 'const unsigned char bindata[] __attribute__((aligned(16))) = {'
    for i in range(len(file_content)):
        if i % 16 == 0:
            outp += '\n'
        outp += '0x%02x, ' % file_content[i]
    outp += '\n};\n'
    return bytes(outp, 'utf-8')

def convert_to_uf2(file_content):
    global familyid
    datapadding = b''
    while len(datapadding) < 512 - 256 - 32 - 4:
        datapadding += b'\x00\x00\x00\x00'
    numblocks = (len(file_content) + 255) // 256
    outp = []
    for blockno in range(numblocks):
        ptr = 256 * blockno
        chunk = file_content[ptr:ptr + 256]
        flags = 0x0
        if familyid:
            flags |= 0x2000
        hd = struct.pack(b'<IIIIIIII',
            UF2_MAGIC_START0, UF2_MAGIC_START1,
            flags, ptr + appstartaddr, 256, blockno, numblocks, familyid)
        while len(chunk) < 256:
            chunk += b'\x00'
        block = hd + chunk + datapadding + struct.pack(b'<I', UF2_MAGIC_END)
        assert len(block) == 512
        outp.append(block)
    return b''.join(outp)

class Block:
    def __init__(self, addr):
        self.addr = addr
        self.bytes = bytearray(256)

    def encode(self, blockno, numblocks):
        global familyid
        flags = 0x0
        if familyid:
            flags |= 0x2000
        hd = struct.pack('<IIIIIIII',
            UF2_MAGIC_START0, UF2_MAGIC_START1,
            flags, self.addr, 256, blockno, numblocks, familyid)
        hd += self.bytes[0:256]
        while len(hd) < 512 - 4:
            hd += b'\x00'
        hd += struct.pack('<I', UF2_MAGIC_END)
        return hd

def convert_from_hex_to_uf2(buf):
    global appstartaddr
    appstartaddr = None
    upper = 0
    currblock = None
    blocks = []
    for line in buf.split('\n'):
        if line[0] != ':':
            continue
        i = 1
        rec = []
        while i < len(line) - 1:
            rec.append(int(line[i:i+2], 16))
            i += 2
        tp = rec[3]
        if tp == 4:
            upper = ((rec[4] << 8) | rec[5]) << 16
        elif tp == 2:
            upper = ((rec[4] << 8) | rec[5]) << 4
        elif tp == 1:
            break
        elif tp == 0:
            addr = upper + ((rec[1] << 8) | rec[2])
            if appstartaddr == None:
                appstartaddr = addr
            i = 4
            while i < len(rec) - 1:
                if not currblock or currblock.addr & ~0xff != addr & ~0xff:
                    currblock = Block(addr & ~0xff)
                    blocks.append(currblock)
                currblock.bytes[addr & 0xff] = rec[i]
                addr += 1
                i += 1
    numblocks = len(blocks)
    resfile = b''
    for i in range(0, numblocks):
        resfile += blocks[i].encode(i, numblocks)
    return resfile

def to_str(b):
    return b.decode('utf-8')

def get_drives():
    drives = []
    if sys.platform == 'win32':
        r = subprocess.check_output(['wmic', 'PATH', 'Win32_LogicalDisk',
                                     'get', 'DeviceID,', 'VolumeName,',
                                     'FileSystem,', 'DriveType'])
        for line in to_str(r).split('\n'):
            words = re.split('\s+', line)
            if len(words) >= 3 and words[1] == '2' and words[2] == 'FAT':
                drives.append(words[0])
    else:
        rootpath = '/media'
        if sys.platform == 'darwin':
            rootpath = '/Volumes'
        elif sys.platform == 'linux':
            tmp = rootpath + '/' + os.environ['USER']
            if os.path.isdir(tmp):
                rootpath = tmp
        for d in os.listdir(rootpath):
            drives.append(os.path.join(rootpath, d))


    def has_info(d):
        try:
            return os.path.isfile(d + INFO_FILE)
        except:
            return False

    return list(filter(has_info, drives))


def board_id(path):
    with open(path + INFO_FILE, mode='r') as file:
        file_content = file.read()
    return re.search('Board-ID: ([^\r\n]*)', file_content).group(1)


def list_drives():
    for d in get_drives():
        print(d, board_id(d))


def write_file(name, buf):
    with open(name, 'wb') as f:
        f.write(buf)
    print('Wrote %d bytes to %s' % (len(buf), name))


def load_families():
    # The expectation is that the `uf2families.json` file is in the same
    # directory as this script. Make a path that works using `__file__`
    # which contains the full path to this script.
    filename = 'uf2families.json'
    pathname = os.path.join(os.path.dirname(os.path.abspath(__file__)), filename)
    with open(pathname) as f:
        raw_families = json.load(f)

    families = {}
    for family in raw_families:
        families[family['short_name']] = int(family['id'], 0)

    return families


def main():
    global appstartaddr, familyid
    def error(msg):
        print(msg)
        sys.exit(1)
    parser = argparse.ArgumentParser(description='Convert to UF2 or flash directly.')
    parser.add_argument('input', metavar='INPUT', type=str, nargs='?',
                        help='input file (HEX, BIN or UF2)')
    parser.add_argument('-b' , '--base', dest='base', type=str,
                        default='0x2000',
                        help='set base address of application for BIN format (default: 0x2000)')
    parser.add_argument('-o' , '--output', metavar='FILE', dest='output', type=str,
                        help='write output to named file; defaults to "flash.uf2" or "flash.bin" where sensible')
    parser.add_argument('-d' , '--device', dest='device_path',
                        help='select a device path to flash')
    parser.add_argument('-l' , '--list', action='store_true',
                        help='list connected devices')
    parser.add_argument('-c' , '--convert', action='store_true',
                        help='do not flash, just convert')
    parser.add_argument('-D' , '--deploy', action='store_true',
                        help='just flash, do not convert')
    parser.add_argument('-f' , '--family', dest='family', type=str,
                        default='0x0',
                        help='specify familyID - number or name (default: 0x0)')
    parser.add_argument('-C' , '--carray', action='store_true',
                        help='convert binary file to a C array, not UF2')
    parser.add_argument('-i', '--info', action='store_true',
                        help='display header information from UF2, do not convert')
    args = parser.parse_args()
    appstartaddr = int(args.base, 0)

    families = load_families()

    if args.family.upper() in families:
        familyid = families[args.family.upper()]
    else:
        try:
            familyid = int(args.family, 0)
        except ValueError:
            error('Family ID needs to be a number or one of: ' + ', '.join(families.keys()))

    if args.list:
        list_drives()
    else:
        if not args.input:
            error('Need input file')
        with open(args.input, mode='rb') as f:
            inpbuf = f.read()
        from_uf2 = is_uf2(inpbuf)
        ext = 'uf2'
        if args.deploy:
            outbuf = inpbuf
        elif from_uf2 and not args.info:
            outbuf = convert_from_uf2(inpbuf)
            ext = 'bin'
        elif from_uf2 and args.info:
            outbuf = ''
            convert_from_uf2(inpbuf)
        elif is_hex(inpbuf):
            outbuf = convert_from_hex_to_uf2(inpbuf.decode('utf-8'))
        elif args.carray:
            outbuf = convert_to_carray(inpbuf)
            ext = 'h'
        else:
            outbuf = convert_to_uf2(inpbuf)
        if not args.deploy and not args.info:
            print('Converted to %s, output size: %d, start address: 0x%x' %
                  (ext, len(outbuf), appstartaddr))
        if args.convert or ext != 'uf2':
            drives = []
            if args.output == None:
                args.output = 'flash.' + ext
        else:
            drives = get_drives()

        if args.output:
            write_file(args.output, outbuf)
        else:
            if len(drives) == 0:
                error('No drive to deploy.')
        for d in drives:
            print('Flashing %s (%s)' % (d, board_id(d)))
            write_file(d + '/NEW.UF2', outbuf)


if __name__ == '__main__':
    main()