#!/usr/bin/env python3
import configparser,ipaddress,json,re,secrets,shutil,subprocess,threading,time
from http import HTTPStatus
from http.server import BaseHTTPRequestHandler,ThreadingHTTPServer
from pathlib import Path
from urllib.parse import parse_qs,urlparse

APP_VERSION="3.6.0"
CFG=Path("/etc/pigway-pi-control.conf")
STATUS=Path("/run/pigway-pi-control/status.json")
TOKEN=Path("/etc/pigway-pi-control-api.token")
WEB=Path("/usr/local/share/pigway-pi-control/web/index.html")
ALLOWED_SECTIONS={"services","processes","alerts","fan","led","timing","dark_mode","display","api"}
NAME_RE=re.compile(r"^[A-Za-z0-9_.-]{1,64}$")
UNIT_RE=re.compile(r"^[A-Za-z0-9_.@:-]{1,128}\.service$")
RGB_KEY_RE=re.compile(r"^(cpu|power|memory|storage|network|service|normal)_[rgb]$")
FLASH_KEY_RE=re.compile(r"^(warning|critical|emergency|normal)_flash_(on|off)_ms$")
NORMAL_MODES={"off","solid","flash","flow","breathe","marquee","rainbow","colorful"}
EFFECT_COLORS={"red","green","blue","yellow","purple","cyan","white"}
PROTECTED_UNITS={"pigway-pi-control-api.service"}

def load_cfg():
    cfg=configparser.ConfigParser(); cfg.read(CFG)
    return cfg

def api_setting(key,default,cast=str):
    try:return cast(load_cfg().get("api",key))
    except Exception:return default

def config_json():
    cfg=load_cfg()
    return {section:dict(cfg.items(section)) for section in cfg.sections() if section in ALLOWED_SECTIONS}

def validate_value(section,key,value,existing):
    if section not in {"services","processes"} and key not in existing.get(section,set()):
        raise ValueError(f"unsupported option: {section}.{key}")
    if RGB_KEY_RE.fullmatch(key):
        number=int(value)
        if not 0<=number<=255: raise ValueError(f"{key} must be 0..255")
    elif FLASH_KEY_RE.fullmatch(key):
        number=int(value)
        if not 50<=number<=60000: raise ValueError(f"{key} must be 50..60000")
    elif section=="led" and key=="normal_mode":
        if value.lower() not in NORMAL_MODES: raise ValueError("normal_mode must be off, solid, flash, flow, breathe, marquee, rainbow or colorful")
    elif section=="led" and key=="normal_effect_speed":
        if int(value) not in (1,2,3): raise ValueError("normal_effect_speed must be 1, 2 or 3")
    elif section=="led" and key=="normal_effect_color":
        if value.lower() not in EFFECT_COLORS: raise ValueError("normal_effect_color must be red, green, blue, yellow, purple, cyan or white")
    elif section=="api" and key=="port":
        number=int(value)
        if not 1<=number<=65535: raise ValueError("api.port must be 1..65535")
    elif section=="api" and key=="log_limit":
        number=int(value)
        if not 1<=number<=1000: raise ValueError("api.log_limit must be 1..1000")
    elif section=="api" and key=="bind":
        ipaddress.ip_address(value)

def update_ini(updates):
    if not isinstance(updates,dict): raise ValueError("updates must be an object")
    text=CFG.read_text()
    current=load_cfg(); existing={section:set(current.options(section)) for section in current.sections()}
    for section,values in updates.items():
        if section not in ALLOWED_SECTIONS or not isinstance(values,dict):
            raise ValueError(f"unsupported section: {section}")
        for key,value in values.items():
            if not NAME_RE.fullmatch(str(key)): raise ValueError(f"invalid key: {key}")
            if value is None:
                raise ValueError(f"null is not allowed: {section}.{key}")
            value=str(value).strip()
            if not value or len(value)>256 or any(c in value for c in "\r\n\x00"):
                raise ValueError(f"invalid value: {section}.{key}")
            validate_value(section,str(key),value,existing)
            section_match=re.search(rf"(?mi)^\[{re.escape(section)}\]\s*$",text)
            if not section_match:
                text=text.rstrip()+f"\n\n[{section}]\n{key} = {value}\n"
                continue
            next_section=re.search(r"(?m)^\[.+\]\s*$",text[section_match.end():])
            end=section_match.end()+(next_section.start() if next_section else len(text)-section_match.end())
            chunk=text[section_match.end():end]
            key_match=re.search(rf"(?mi)^(\s*{re.escape(str(key))}\s*=\s*).*$",chunk)
            if key_match:
                start=section_match.end()+key_match.start(); stop=section_match.end()+key_match.end()
                replacement=key_match.group(1)+value
                text=text[:start]+replacement+text[stop:]
            else:
                text=text[:end].rstrip()+f"\n{key} = {value}\n\n"+text[end:].lstrip("\n")
    parsed=configparser.ConfigParser(); parsed.read_string(text)
    backup=CFG.with_name(f"{CFG.name}.bak.api-{time.strftime('%Y%m%d-%H%M%S')}")
    shutil.copy2(CFG,backup)
    temporary=CFG.with_suffix(".tmp")
    temporary.write_text(text); temporary.chmod(0o644); temporary.replace(CFG)
    return str(backup)

def journal_query(since=None,until=None,severity="",event="",search="",sort="timestamp",order="desc",limit=100,offset=0):
    command=["journalctl","-u","pigway-pi-control.service","--no-pager","-o","json"]
    if since is not None: command.extend(["--since",f"@{since}"])
    if until is not None: command.extend(["--until",f"@{until}"])
    result=subprocess.run(command,capture_output=True,text=True,timeout=15)
    if result.returncode: raise RuntimeError(result.stderr.strip() or "journalctl failed")
    rows=[]
    for line in result.stdout.splitlines():
        try:
            item=json.loads(line)
            message=item.get("MESSAGE","")
            level_match=re.search(r"(?:^|\s)level=([A-Z]+)(?:\s|$)",message)
            event_match=re.search(r"(?:^|\s)event=([^ ]+)",message)
            priority=str(item.get("PRIORITY","6"))
            level=(level_match.group(1) if level_match else
                   {"0":"EMERGENCY","1":"ALERT","2":"CRITICAL","3":"ERROR","4":"WARN","5":"NOTICE","6":"INFO","7":"DEBUG"}.get(priority,"INFO"))
            rows.append({"timestamp":int(item.get("__REALTIME_TIMESTAMP",0)),"priority":priority,
                         "severity":level,"event":event_match.group(1) if event_match else "SYSTEM",
                         "message":message})
        except json.JSONDecodeError: pass
    severities={x.strip().upper() for x in severity.split(",") if x.strip()}
    if severities: rows=[x for x in rows if x["severity"] in severities]
    event_types=sorted({x["event"] for x in rows})
    if event: rows=[x for x in rows if x["event"]==event]
    if search:
        needle=search.casefold(); rows=[x for x in rows if needle in x["message"].casefold()]
    severity_rank={"EMERGENCY":0,"ALERT":1,"CRITICAL":2,"ERROR":3,"WARN":4,"NOTICE":5,"INFO":6,"DEBUG":7}
    keys={"timestamp":lambda x:x["timestamp"],"severity":lambda x:severity_rank.get(x["severity"],99),
          "event":lambda x:x["event"],"message":lambda x:x["message"]}
    rows.sort(key=keys[sort],reverse=order=="desc")
    total=len(rows)
    return {"logs":rows[offset:offset+limit],"total":total,"offset":offset,"limit":limit,
            "event_types":event_types,"retention":"systemd-journal"}

def service_inventory():
    cfg=load_cfg()
    monitored={target.lower():(name,target) for name,target in cfg.items("services")} if cfg.has_section("services") else {}
    notes=dict(cfg.items("service_notes")) if cfg.has_section("service_notes") else {}
    files=subprocess.run(["systemctl","list-unit-files","--type=service","--no-legend","--no-pager"],
                         capture_output=True,text=True,timeout=10,check=True)
    units={}
    for line in files.stdout.splitlines():
        parts=line.split()
        if len(parts)>=2 and UNIT_RE.fullmatch(parts[0]):
            units[parts[0]]={"unit":parts[0],"enabled":parts[1],"active":"inactive","description":""}
    states=subprocess.run(["systemctl","list-units","--all","--type=service","--no-legend","--no-pager","--plain"],
                          capture_output=True,text=True,timeout=10,check=True)
    for line in states.stdout.splitlines():
        parts=line.split(None,4)
        if len(parts)>=4 and UNIT_RE.fullmatch(parts[0]):
            item=units.setdefault(parts[0],{"unit":parts[0],"enabled":"unknown"})
            item.update({"active":parts[2],"description":parts[4] if len(parts)>4 else ""})
    for name,target in monitored.values():
        item=units.setdefault(target,{"unit":target,"enabled":"not-found","active":"inactive","description":""})
        item.update({"monitored":True,"monitor_name":name.upper(),"note":notes.get(name,"")})
    for item in units.values():
        item.setdefault("monitored",False); item.setdefault("monitor_name",""); item.setdefault("note","")
        item["protected"]=item["unit"] in PROTECTED_UNITS
    return sorted(units.values(),key=lambda x:(not x["monitored"],x["unit"]))

def edit_service_monitor(operation,name,target,note="",previous_name=""):
    if operation not in {"save","delete"}: raise ValueError("operation must be save or delete")
    if not NAME_RE.fullmatch(name): raise ValueError("invalid monitor name")
    if not UNIT_RE.fullmatch(target): raise ValueError("invalid systemd service name")
    if len(note)>120 or any(c in note for c in "\r\n\x00"): raise ValueError("invalid note")
    if previous_name and not NAME_RE.fullmatch(previous_name): raise ValueError("invalid previous monitor name")
    cfg=load_cfg(); old_target=cfg.get("services",name,fallback=None)
    text=CFG.read_text()
    def change(section,key,value):
        nonlocal text
        section_match=re.search(rf"(?mi)^\[{re.escape(section)}\]\s*$",text)
        if not section_match:
            if value is not None: text=text.rstrip()+f"\n\n[{section}]\n{key} = {value}\n"
            return
        next_section=re.search(r"(?m)^\[.+\]\s*$",text[section_match.end():])
        end=section_match.end()+(next_section.start() if next_section else len(text)-section_match.end())
        chunk=text[section_match.end():end]
        key_match=re.search(rf"(?mi)^\s*{re.escape(key)}\s*=.*(?:\n|$)",chunk)
        if key_match:
            start=section_match.end()+key_match.start(); stop=section_match.end()+key_match.end()
            text=text[:start]+((f"{key} = {value}\n") if value is not None else "")+text[stop:]
        elif value is not None:
            text=text[:end].rstrip()+f"\n{key} = {value}\n\n"+text[end:].lstrip("\n")
    if operation=="delete":
        if old_target is None: raise ValueError("monitor not found")
        change("services",name,None); change("service_notes",name,None)
    else:
        if previous_name and previous_name.lower()!=name.lower():
            change("services",previous_name,None); change("service_notes",previous_name,None)
        change("services",name,target); change("service_notes",name,note or None)
    parsed=configparser.ConfigParser(); parsed.read_string(text)
    backup=CFG.with_name(f"{CFG.name}.bak.api-{time.strftime('%Y%m%d-%H%M%S')}")
    shutil.copy2(CFG,backup)
    temporary=CFG.with_suffix(".tmp"); temporary.write_text(text); temporary.chmod(0o644); temporary.replace(CFG)
    subprocess.run(["systemctl","restart","pigway-pi-control.service"],check=True,timeout=10)
    return str(backup)

def control_service(unit,action):
    if not UNIT_RE.fullmatch(unit): raise ValueError("invalid systemd service name")
    if action not in {"start","stop"}: raise ValueError("action must be start or stop")
    if unit in PROTECTED_UNITS and action=="stop": raise ValueError("protected remote-management service cannot be stopped here")
    result=subprocess.run(["systemctl",action,unit],capture_output=True,text=True,timeout=20)
    if result.returncode: raise RuntimeError(result.stderr.strip() or f"systemctl {action} failed")

class Handler(BaseHTTPRequestHandler):
    server_version="PIGWayAPI/3.6"

    def log_message(self,fmt,*args):
        return

    def send_json(self,status,payload):
        data=json.dumps(payload,ensure_ascii=False,separators=(",",":")).encode()
        self.send_response(status); self.send_header("Content-Type","application/json; charset=utf-8")
        self.send_header("Content-Length",str(len(data))); self.security_headers(); self.end_headers(); self.wfile.write(data)

    def security_headers(self):
        self.send_header("Cache-Control","no-store")
        self.send_header("X-Content-Type-Options","nosniff")
        self.send_header("X-Frame-Options","DENY")
        self.send_header("Content-Security-Policy","default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline'")

    def authorized(self):
        try: expected=TOKEN.read_text().strip()
        except OSError: return False
        supplied=self.headers.get("Authorization","")
        return supplied.startswith("Bearer ") and secrets.compare_digest(supplied[7:],expected)

    def read_json(self):
        length=int(self.headers.get("Content-Length","0"))
        if length<=0 or length>65536: raise ValueError("invalid request size")
        return json.loads(self.rfile.read(length))

    def do_GET(self):
        parsed=urlparse(self.path)
        try:
            if parsed.path=="/":
                data=WEB.read_bytes(); self.send_response(200); self.send_header("Content-Type","text/html; charset=utf-8")
                self.send_header("Content-Length",str(len(data))); self.security_headers(); self.end_headers(); self.wfile.write(data); return
            if parsed.path=="/api/v1/health":
                self.send_json(200,{"ok":True,"version":APP_VERSION,"status_available":STATUS.exists()}); return
            if parsed.path=="/api/v1/status":
                if not STATUS.exists(): self.send_json(503,{"error":"agent status unavailable"}); return
                self.send_json(200,json.loads(STATUS.read_text())); return
            if parsed.path=="/api/v1/logs":
                query=parse_qs(parsed.query)
                value=lambda key,default="":query.get(key,[default])[0]
                limit=min(max(int(value("limit",api_setting("log_limit",200,int))),1),500)
                offset=max(int(value("offset",0)),0)
                since=int(value("since")) if value("since") else None
                until=int(value("until")) if value("until") else None
                if since is not None and until is not None and since>until: raise ValueError("since must not be after until")
                sort=value("sort","timestamp"); order=value("order","desc")
                if sort not in {"timestamp","severity","event","message"}: raise ValueError("invalid log sort")
                if order not in {"asc","desc"}: raise ValueError("invalid log order")
                severity=value("severity").upper(); event=value("event"); search=value("search")
                if len(event)>80 or len(search)>120: raise ValueError("log filter is too long")
                self.send_json(200,journal_query(since,until,severity,event,search,sort,order,limit,offset)); return
            if parsed.path=="/api/v1/config":
                self.send_json(200,{"config":config_json(),"write_requires_token":True}); return
            if parsed.path=="/api/v1/services":
                self.send_json(200,{"services":service_inventory()}); return
            self.send_json(404,{"error":"not found"})
        except ValueError as e: self.send_json(400,{"error":str(e)})
        except Exception as e: self.send_json(500,{"error":str(e)})

    def do_PUT(self):
        path=urlparse(self.path).path
        if path not in {"/api/v1/config","/api/v1/services","/api/v1/services/control"}: self.send_json(404,{"error":"not found"}); return
        if not self.authorized(): self.send_json(401,{"error":"bearer token required"}); return
        try:
            body=self.read_json()
            if path=="/api/v1/services/control":
                control_service(str(body.get("unit","")),str(body.get("action","")))
                print(f"SERVICE_CONTROL action={body.get('action')} unit={body.get('unit')}",flush=True)
                self.send_json(200,{"ok":True}); return
            if path=="/api/v1/services":
                backup=edit_service_monitor(str(body.get("operation","")),str(body.get("name","")),
                                            str(body.get("target","")),str(body.get("note","")),
                                            str(body.get("previous_name","")))
                print(f"SERVICE_MONITOR_UPDATED operation={body.get('operation')} target={body.get('target')} backup={backup}",flush=True)
                self.send_json(200,{"ok":True,"backup":backup}); return
            updates=body.get("updates")
            backup=update_ini(updates)
            subprocess.run(["systemctl","restart","pigway-pi-control.service"],check=True,timeout=10)
            restart_api="api" in updates
            print(f"CONFIG_UPDATED sections={','.join(sorted(updates))} backup={backup}",flush=True)
            self.send_json(200,{"ok":True,"backup":backup,"api_restart":restart_api})
            if restart_api: threading.Timer(0.2,self.server.shutdown).start()
        except (ValueError,json.JSONDecodeError) as e: self.send_json(400,{"error":str(e)})
        except Exception as e: self.send_json(500,{"error":str(e)})

def main():
    host=api_setting("bind","0.0.0.0")
    port=api_setting("port",6001,int)
    server=ThreadingHTTPServer((host,port),Handler)
    print(f"API_START version={APP_VERSION} bind={host} port={port}",flush=True)
    try: server.serve_forever()
    finally: server.server_close()

if __name__=="__main__": main()