import os
import time
from dataclasses import asdict, dataclass, replace

from resources.fields import Loaded
from resources.base import names
from engine.stored import read_json, write_json
from engine import runtime
from engine.memo import Memo

PERCENT, USES, MINUTES, IDLE, WORKED, START, NOTICES = "percent", "uses", "minutes", "idle", "worked", "start", "notices"
UNITS = (PERCENT, USES, MINUTES, IDLE, WORKED, START, NOTICES)
HELD = Memo()
TRIGGER = names("unit", "on", "every", "at")
MINUTE = 60.0
DAY = 24 * 60 * MINUTE


@dataclass(frozen=True)
class Trigger(Loaded):
    unit: str = ""
    every: float = 0
    at: tuple = ()
    on: str = ""

    def __bool__(self) -> bool:
        return bool(self.unit or self.on)

    def described(self) -> dict:
        return {key: list(value) if key == TRIGGER.at else value for key, value in
                ((TRIGGER.unit, self.unit), (TRIGGER.every, self.every), (TRIGGER.at, self.at), (TRIGGER.on, self.on)) if value}


@dataclass(frozen=True)
class Mark(Loaded):
    context: float = 0.0
    uses: int = 0
    status: str = ""
    event: str = ""
    at: float = 0.0
    count: int = 0
    edits: int = 0
    since: float = 0.0
    notified: bool | None = None
    notices: int = 0
    viewer_opened: bool = False


NEVER = Trigger()


def saved(record, name: str, default: Trigger) -> Trigger:
    kept = record.triggers.get(name)
    return Trigger.from_json(kept) if isinstance(kept, dict) else default


def _file(record, session: str, name: str):
    return runtime.session_file(record.root, session, f"trigger-{name}.json")


def last(record, session: str, name: str) -> Mark:
    f = str(_file(record, session, name))
    stamp = stamped(f)
    return HELD.get(f, stamp, lambda: read_json(f, Mark.from_json, Mark.from_json({})))


def held(f: str, mark: Mark) -> None:
    HELD.put(f, stamped(f), mark)


def stamped(f: str) -> int:
    try:
        return os.stat(f).st_mtime_ns
    except OSError:
        return 0


def due(record, agent, name: str, cadence: Trigger) -> bool:
    if not cadence:
        return False
    was = last(record, agent.title, name)
    observe(record, agent, name, was)
    unit, every = cadence.unit if cadence.unit else cadence.on, float(cadence.every) if cadence.every else 1.0
    context, uses, status, event = was.context, was.uses, was.status, was.event
    if unit == PERCENT and cadence.at:
        return any(context < mark <= float(agent.context) for mark in cadence.at)
    if unit == PERCENT:
        return int(float(agent.context) // every) > int(context // every)
    if unit == USES:
        return int(agent.uses) - uses >= every
    if unit == MINUTES:
        return time.time() - was.at >= every * MINUTE
    if unit == IDLE:
        return agent.status == IDLE and status != IDLE
    if unit == WORKED:
        return agent.status == IDLE and status != IDLE and int(agent.uses) > uses
    if unit == START:
        return agent.event == "SessionStart" and event != "SessionStart"
    if unit == NOTICES:
        return was.notices >= every
    return False


def claimed(record, agent, name: str, cadence: Trigger) -> bool:
    first = cadence.unit == USES and not last(record, agent.title, name).at
    if not first and not due(record, agent, name, cadence):
        return False
    fired(record, agent, name)
    return True


def write(record, agent, name: str, **fields) -> None:
    was = last(record, agent.title, name)
    now = replace(was, **fields)
    if now != was:
        f = str(_file(record, agent.title, name))
        write_json(f, asdict(now))
        held(f, now)


def observe(record, agent, name: str, was: Mark) -> None:
    if (was.status, was.event) != (agent.status, agent.event):
        held(str(_file(record, agent.title, name)), replace(was, status=agent.status, event=agent.event))


def fired(record, agent, name: str) -> None:
    write(record, agent, name, at=time.time(), context=agent.context, uses=agent.uses, notices=0)


def noticed(record, agent, name: str) -> None:
    write(record, agent, name, notices=last(record, agent.title, name).notices + 1)