"""Serialised ESPHome CLI jobs. YAML/secrets stay local; no shell or arbitrary commands."""
import asyncio
from collections import deque
import glob
import json
import os
from pathlib import Path
import re
import shutil
import signal
import time
import yaml
from core import REPO, installation_yaml

# libyaml parses a 300 KB profile roughly ten times faster than the pure-Python loader.
class LenientLoader(yaml.CSafeLoader if getattr(yaml, '__with_libyaml__', False) else yaml.SafeLoader):
    """Reads profile metadata without resolving !secret or !include."""
LenientLoader.add_multi_constructor('!', lambda loader, suffix, node: None)

def profile_meta(text):
    """{'node', 'friendly'} from profile YAML, or None when it has no esphome block."""
    data = yaml.load(text, Loader=LenientLoader)
    block = data.get('esphome') if isinstance(data, dict) else None
    if not isinstance(block, dict):
        return None
    substitutions = data.get('substitutions') if isinstance(data.get('substitutions'), dict) else {}
    def resolve(value):
        if isinstance(value, str) and value.startswith('${') and value.endswith('}'):
            value = substitutions.get(value[2:-1])
        return value if isinstance(value, str) else None
    # 'screen': the profile pulls this project's board package, so it is one of ours (not any ESPHome device).
    packages = data.get('packages') if isinstance(data.get('packages'), dict) else {}
    ours = any(isinstance(entry, dict) and REPO in str(entry.get('url', '')) for entry in packages.values())
    api = data.get('api') if isinstance(data.get('api'), dict) else {}
    encryption = api.get('encryption') if isinstance(api.get('encryption'), dict) else {}
    key = encryption.get('key')
    return {'node': resolve(block.get('name')), 'friendly': resolve(block.get('friendly_name')),
            'screen': ours, 'api_key': key if isinstance(key, str) else None}

class Firmware:
    OVERRIDE_SUFFIX = '.local.yaml'
    OVERRIDE_LIMIT = 12 * 1024  # bytes; checked here, far below the request body limit (128 KB since app 0.2.78)
    PROTECTED_OVERRIDE_KEYS = frozenset({'esphome', 'api', 'ota', 'wifi', 'packages',
                                         'external_components', 'captive_portal'})
    PROTECTED_SUBSTITUTIONS = frozenset({'DEVICE_NAME', 'DEVICE_FRIENDLY_NAME', 'SCREEN_FIRMWARE_VERSION'})
    # ESPHome's "Factory format" (bootloader, partition table and app from address 0), the file ESPHome Web
    # flashes on a board. A build writes it next to firmware.bin: under .pioenvs/<node>/ with PlatformIO,
    # under build/ with ESPHome's native ESP-IDF toolchain.
    FACTORY_IMAGES = ('*/.pioenvs/*/firmware.factory.bin', '*/build/firmware.factory.bin')

    def __init__(self, root, data):
        self.root, self.data = Path(root).resolve(), Path(data)
        self.job = None
        self.task = None
        self.logs = deque(maxlen=300)
        self.process = None
        self.installed = set()  # profiles this process flashed successfully; the page nudges pairing for them
        # Factory image per profile from its last successful build in this process; only these are downloaded,
        # so a download is never older than the profile's latest build. Downloaded ones get their own pairing nudge.
        self.images = {}
        self.downloaded = set()
        self._names = {}  # file -> (stat signature, meta or None); parsed only when the file changes

    def profiles(self):
        if not self.root.exists(): return []
        return [{'file': p.name} for p in sorted(self.root.glob('*.yaml'))
                if p.name != 'secrets.yaml' and not p.name.endswith(self.OVERRIDE_SUFFIX)
                and p.is_file() and not p.is_symlink()]

    def profile_names(self):
        """{file: {'node': esphome name, 'friendly': friendly name}} for every readable profile.

        Parsing is cached per file on inode, mtime and size, so a request only pays for changed
        profiles. The dict is rebuilt from the current directory listing, so deleted files drop out.
        """
        found, cache = {}, {}
        for entry in self.profiles():
            path = self.root / entry['file']
            try:
                st = path.stat()
                key = (st.st_ino, st.st_mtime_ns, st.st_size)
                cached = self._names.get(entry['file'])
                if cached and cached[0] == key:
                    meta = cached[1]
                else:
                    meta = profile_meta(path.read_text())
            except (OSError, yaml.YAMLError, UnicodeError):
                continue
            cache[entry['file']] = (key, meta)
            if meta:
                found[entry['file']] = meta
        self._names = cache
        return found

    def ports(self):
        return sorted(set(glob.glob('/dev/serial/by-id/*') or glob.glob('/dev/ttyUSB*') + glob.glob('/dev/ttyACM*')))

    def profile(self, name):
        if not isinstance(name,str) or not re.fullmatch(r'[a-zA-Z0-9_-]+\.yaml', name):
            raise ValueError('Choose an existing YAML profile.')
        p = self.root / name
        if p.is_symlink() or p.resolve().parent != self.root or not p.is_file():
            raise ValueError("Profile doesn't exist in the ESPHome folder.")
        return p

    def wifi_status(self):
        # Return availability only; never send secret values to the browser.
        path = self.root / 'secrets.yaml'
        if not path.exists():
            return {'state': 'new', 'missing': ['wifi_ssid', 'wifi_password']}
        try:
            values = yaml.safe_load(path.read_text())
            if not isinstance(values, dict):
                return {'state': 'invalid'}
            missing = [key for key in ('wifi_ssid', 'wifi_password')
                       if not isinstance(values.get(key), str)]
            if isinstance(values.get('wifi_ssid'), str) and not values['wifi_ssid'].strip():
                missing.append('wifi_ssid')
            return {'state': 'missing' if missing else 'ready', 'missing': missing}
        except (OSError, yaml.YAMLError, UnicodeError):
            return {'state': 'invalid'}

    def status(self):
        return {'available': bool(shutil.which('esphome')), 'profiles': self.profiles(),
                'ports': self.ports(), 'job': self.job, 'logs': list(self.logs), 'wifi': self.wifi_status(),
                'downloads': sorted(self.images)}

    def store_wifi(self, data):
        """Put wifi_ssid/wifi_password in secrets.yaml when they are missing. Existing values and
        every other secret stay as they are; the browser never sees stored values."""
        wifi = self.wifi_status()
        if wifi['state'] == 'ready':
            return
        if wifi['state'] == 'invalid':
            raise ValueError("secrets.yaml in the ESPHome folder isn't valid YAML. Fix the file first; it won't be overwritten.")
        values = {}
        for key in wifi['missing']:
            value = data.get(key)
            if not isinstance(value, str) or (key == 'wifi_ssid' and not value.strip()):
                raise ValueError("Fill in the Wi-Fi name and password; they'll be saved in ESPHome secrets.yaml.")
            values[key] = value
        path = self.root / 'secrets.yaml'
        if wifi['state'] == 'new':
            with path.open('x') as f:
                os.chmod(path, 0o600)
                yaml.safe_dump(values, f, width=4096)
            return
        # An existing file with missing keys: replace only that key's own line, or append it.
        text = path.read_text()
        for key, value in values.items():
            line = yaml.safe_dump({key: value}, width=4096).strip()
            pattern = re.compile(rf'^{key}\s*:.*$', re.M)
            if pattern.search(text):
                text = pattern.sub(lambda match: line, text, count=1)
            else:
                text = text + ('' if not text or text.endswith('\n') else '\n') + line + '\n'
        check = yaml.safe_load(text)
        if not isinstance(check, dict) or any(check.get(key) != value for key, value in values.items()):
            raise ValueError("Wi-Fi couldn't be set in secrets.yaml. Fill in wifi_ssid and wifi_password there yourself.")
        path.write_text(text)

    def create(self, data):
        """Write the device profile, its empty local override, and any missing wifi secrets."""
        content = installation_yaml(data)
        self.root.mkdir(parents=True,exist_ok=True)
        profile = self.root / (data['name']+'.yaml')
        if profile.exists() or profile.is_symlink():
            raise ValueError('This name already exists. Use the existing profile for updates.')
        override = self.root / (data['name'] + self.OVERRIDE_SUFFIX)
        if override.exists() or override.is_symlink():
            raise ValueError('This name already has a local override. Restore or remove it before creating a new screen with this name.')
        self.store_wifi(data)
        try:
            with profile.open('x') as f:
                os.chmod(profile,0o600);f.write(content)
        except FileExistsError:
            raise ValueError('This name already exists. Use the existing profile for updates.')
        try:
            with override.open('x') as f:
                os.chmod(override, 0o600); f.write('{}\n')
        except FileExistsError:
            raise ValueError('This name already has a local override. Restore or remove it before creating a new screen with this name.')
        key = yaml.load(content, Loader=LenientLoader)['api']['encryption']['key']
        # The key is what Home Assistant asks for when pairing; the page shows it once.
        return {'file': profile.name, 'node': data['name'], 'api_key': key}

    def _override_path(self, name):
        profile = self.profile(name)
        path = self.root / (profile.stem + self.OVERRIDE_SUFFIX)
        if path.is_symlink():
            raise ValueError('The local override is a symbolic link; replace it with a regular file first.')
        return profile, path

    def _atomic_write(self, path, text):
        temporary = path.with_name(path.name + '.tmp')
        with temporary.open('w', encoding='utf8') as handle:
            os.chmod(temporary, 0o600)
            handle.write(text)
            handle.flush()
            os.fsync(handle.fileno())
        temporary.replace(path)

    def _ensure_override_include(self, profile):
        """Attach an existing profile to its sidecar without reformatting user YAML."""
        filename = profile.stem + self.OVERRIDE_SUFFIX
        text = profile.read_text()
        if re.search(rf'(?m)^\s*local_overrides:\s*!include\s+{re.escape(filename)}\s*$', text):
            return False
        if re.search(r'(?m)^\s*local_overrides\s*:', text):
            raise ValueError('This profile already has a different local_overrides include.')
        try:
            parsed = yaml.load(text, Loader=LenientLoader)
        except yaml.YAMLError as error:
            raise ValueError("The screen profile isn't valid YAML; fix it before adding an override.") from error
        packages = parsed.get('packages') if isinstance(parsed, dict) else None
        if not isinstance(packages, dict):
            raise ValueError("This profile has no packages section that ESP Screens can extend.")
        match = re.search(r'(?m)^packages:\s*\n', text)
        if not match:
            raise ValueError("This profile has no packages section that ESP Screens can extend.")
        next_top = re.search(r'(?m)^[^\s#][^\n]*\n', text[match.end():])
        if not next_top and not text.endswith('\n'):
            text += '\n'
        end = match.end() + next_top.start() if next_top else len(text)
        addition = f'  local_overrides: !include {filename}\n'
        self._atomic_write(profile, text[:end] + addition + text[end:])
        self._names.pop(profile.name, None)
        return True

    def _validate_override(self, content):
        if not isinstance(content, str):
            raise ValueError('Enter YAML text first.')
        if len(content.encode('utf8')) > self.OVERRIDE_LIMIT:
            raise ValueError('The override is too large. Keep it below 12 KB.')
        if not content.strip():
            content = '{}\n'
        try:
            parsed = yaml.load(content, Loader=LenientLoader)
        except yaml.YAMLError as error:
            problem = getattr(error, 'problem', None) or 'invalid YAML'
            mark = getattr(error, 'problem_mark', None)
            where = f' on line {mark.line + 1}' if mark else ''
            raise ValueError(f'YAML error{where}: {problem}.') from error
        if not isinstance(parsed, dict):
            raise ValueError('The override must contain a YAML object, for example display: or substitutions:.')
        protected = sorted(set(parsed) & self.PROTECTED_OVERRIDE_KEYS)
        if protected:
            raise ValueError('These sections stay managed by ESP Screens: ' + ', '.join(protected) + '.')
        substitutions = parsed.get('substitutions')
        if isinstance(substitutions, dict):
            protected = sorted(set(substitutions) & self.PROTECTED_SUBSTITUTIONS)
            if protected:
                raise ValueError('These substitutions stay managed by ESP Screens: ' + ', '.join(protected) + '.')
        return content if content.endswith('\n') else content + '\n'

    def override(self, name):
        profile, path = self._override_path(name)
        attached = bool(re.search(rf'(?m)^\s*local_overrides:\s*!include\s+{re.escape(path.name)}\s*$',
                                  profile.read_text()))
        content = path.read_text() if path.exists() else '{}\n'
        return {'file': profile.name, 'override_file': path.name, 'attached': attached,
                'exists': path.exists(), 'content': content}

    def save_override(self, name, content):
        profile, path = self._override_path(name)
        content = self._validate_override(content)
        # The sidecar first: a profile must never include a file that isn't there.
        self._atomic_write(path, content)
        self._ensure_override_include(profile)
        return self.override(profile.name)

    def install(self, data):
        """Profile plus, when a USB port is chosen, the build and flash in one go. With the target
        'download' it builds only, and the owner flashes the image from their own computer.

        The target and the job slot are checked before anything is written, so a refused
        install leaves no half-made profile behind."""
        target = data.get('target') or ''
        if target:
            if target != 'download' and (not isinstance(target, str) or target not in self.ports()):
                raise ValueError('Choose the connected USB port from the list.')
            if self.task and not self.task.done():
                raise ValueError('A build or installation is already running. Wait for it to finish.')
            if not shutil.which('esphome'):
                raise ValueError('The ESPHome CLI is missing from this installation.')
        result = self.create(data)
        if target == 'download':
            result['job'] = self.start({'file': result['file'], 'action': 'download'})
        elif target:
            result['job'] = self.start({'file': result['file'], 'action': 'install', 'target': target})
        return result

    def factory_image(self, profile):
        """The factory image in this profile's own build folder, or None. The newest wins: a renamed node
        leaves its old folder behind."""
        build = self.data / 'build' / profile.stem
        found = [path for pattern in self.FACTORY_IMAGES for path in build.glob(pattern)
                 if path.is_file() and not path.is_symlink()]
        return max(found, key=lambda path: path.stat().st_mtime_ns) if found else None

    def image(self, name):
        """(path, file name) of the image a profile's last build made, for the page's download.

        Only an image built by this process counts, and a new job for the profile withdraws it first, so the
        owner never gets firmware from before a change or a failed build."""
        profile = self.profile(name)
        if self.job and self.job.get('file') == profile.name and self.job.get('state') == 'running':
            raise ValueError('The firmware is still being built. Download it when the build has finished.')
        path = self.images.get(profile.name)
        if not path or not path.is_file():
            raise ValueError('Build the firmware first; the download appears when the build has finished.')
        self.downloaded.add(profile.name)
        return path, profile.stem + '.factory.bin'

    def redact(self, text):
        text = re.sub(r'\x1b\[[0-?]*[ -/]*[@-~]', '', text)
        for value in self._secret_values:
            if len(value) >= 3: text=text.replace(value,'[redacted]')
        return re.sub(r'(?i)((?:password|encryption.key|token|ssid)\s*[:=]\s*).+',r'\1[redacted]',text)[:1500]

    def start(self, data):
        if self.task and not self.task.done(): raise ValueError('A build or installation is already running.')
        profile = self.profile(data.get('file'))
        action = data.get('action')
        if action not in ('validate','build','install','download'): raise ValueError('Unknown firmware action.')
        if not shutil.which('esphome'): raise ValueError('The ESPHome CLI is missing from this installation.')
        target = data.get('target','')
        if action == 'install':
            if target.startswith('/dev/'):
                if target not in self.ports(): raise ValueError('Choose the connected USB port from the list.')
            elif not re.fullmatch(r'[a-zA-Z0-9][a-zA-Z0-9.-]{0,252}',target):
                raise ValueError('Enter the IP address or hostname of the intended screen.')
        self._secret_values=set()
        # Collect scalar literals, including !secret values, without executing YAML tags.
        def collect(node):
            if isinstance(node,yaml.ScalarNode):
                if node.value: self._secret_values.add(node.value)
            elif isinstance(node,yaml.SequenceNode):
                for child in node.value: collect(child)
            elif isinstance(node,yaml.MappingNode):
                for key,value in node.value:
                    if key.value in ('password','key','ssid','token') or profile.name=='secrets.yaml':collect(value)
                    elif isinstance(value,(yaml.MappingNode,yaml.SequenceNode)):collect(value)
        collect(yaml.compose(profile.read_text()))
        secret_file=self.root/'secrets.yaml'
        if secret_file.exists():
            node=yaml.compose(secret_file.read_text())
            if isinstance(node,yaml.MappingNode):
                for _,v in node.value:collect(v)
        override_file = self.root / (profile.stem + self.OVERRIDE_SUFFIX)
        if override_file.exists() and not override_file.is_symlink():
            collect(yaml.compose(override_file.read_text()))
        self.images.pop(profile.name, None)  # until this job succeeds, the old image may no longer match the profile
        self.logs.clear()
        self.job={'file':profile.name,'action':action,'target':target,'state':'running','started':time.time()}
        self.task=asyncio.create_task(self.run(profile,action,target))
        return dict(self.job)

    async def run(self, profile, action, target):
        env={**os.environ, 'PLATFORMIO_CORE_DIR':str(self.data/'platformio'), 'ESPHOME_BUILD_PATH':str(self.data/'build'/profile.stem), 'NO_COLOR':'1'}
        try:
            stages = ['config'] if action=='validate' else ['compile'] + (['upload'] if action=='install' else [])
            for stage in stages:
                cmd=['esphome']+(['--quiet'] if stage=='config' else [])+[stage,str(profile)]
                if stage=='upload': cmd += ['--device',target]
                self.job['stage']=stage
                self.logs.append('ESPHome: '+stage)
                self.process=await asyncio.create_subprocess_exec(*cmd,cwd=self.root,env=env,stdout=asyncio.subprocess.PIPE,stderr=asyncio.subprocess.STDOUT,limit=1024*1024,start_new_session=True)
                async with asyncio.timeout(7200):
                    async for line in self.process.stdout:
                        self.logs.append(self.redact(line.decode(errors='replace').rstrip()))
                    code=await self.process.wait()
                if code: raise RuntimeError('ESPHome '+stage+' failed; see the log.')
            image = self.factory_image(profile) if action != 'validate' else None
            if action == 'download' and not image:
                raise RuntimeError('ESPHome built no factory image (firmware.factory.bin) to download; see the log.')
            self.job['state']='success'; self.logs.append('Succeeded: '+action)
            if action=='install': self.installed.add(profile.name)
            if image: self.images[profile.name] = image
        except asyncio.CancelledError:
            self.job['state']='interrupted'
            raise
        except Exception as error:
            self.job['state']='failed';self.logs.append(self.redact(str(error)))
        finally:
            if self.process and self.process.returncode is None:
                os.killpg(self.process.pid,signal.SIGTERM)
                try: await asyncio.wait_for(self.process.wait(),10)
                except TimeoutError: os.killpg(self.process.pid,signal.SIGKILL);await self.process.wait()
            self.process=None
            self.job['finished']=time.time()