"""The ingress UI: status, commissioning checks and the two buttons that matter.

Served inside Home Assistant, so no authentication of our own and no external
port. All URLs here are RELATIVE - ingress serves the add-on under a generated
path prefix, and an absolute "/status" would 404 in the field while working
perfectly on a developer's laptop.

Design bias: this page must be readable at the end of a long day, on a phone, in
a cellar, by someone who did not write it. Numbers alone are not enough - it
says what is wrong in words.

⚠️ SINCE UX-02 THERE ARE TWO PAGES HERE, AND ONLY ONE OF THEM IS THIS FILE'S.
`/` is the status and control surface; since UX-13 P1 its files are in
app/static/ and its Home screen reads the structured half of `/status`
(app/homeview.py). `/config` is the
configuration surface: its markup lives in app/config_page.py, its field model
in app/configui.py and its Supervisor conversation in app/selfconfig.py. What
stays HERE is the routing, so that the question a reviewer has to answer - does
anything the panel exposes reach the inverter? - is answered by reading one
short file.

⚠️ THE ANSWER TO THAT QUESTION, STATED SO IT CAN BE CHECKED: the configuration
routes below read `GET /addons/self/info`, run the SHIPPED validator, write
`POST /addons/self/options` and, on an explicitly confirmed request, `POST
/addons/self/restart`. NONE of them writes a setpoint, clears a latch, changes a
mode or reaches `controller.handle_action()`. The set of things an operator can
do to the inverter through this panel is exactly what `/action` offered before
this card - test_selfconfig.py part 7 asserts that by listing the routes and the
actions and comparing them with the shipped set. UX-13's `ha/entities` is a GET
of Home Assistant's entity list (app/haentities.py) and writes nothing.
"""

import io
import json
import logging
import os

from aiohttp import web

from . import messages, selfconfig
from .haentities import EntityCache
from .homeview import region_of
from .validate import config_notes
from .config_page import CONFIG_PAGE
from .configui import changed_keys, field_model, problems_by_field

_LOG = logging.getLogger("goodwe.web")

# UX-13 P1: the page lives in app/static/ as three files - index.html,
# app.css, app.js - plus the page words from app/ui_text/en.json. They are
# joined into ONE response here, once, so the page needs no second request
# and no route of its own: the route list below is unchanged, and every URL
# the page uses stays relative (ingress). No build step, no external file.
STATIC = os.path.join(os.path.dirname(os.path.abspath(__file__)), "static")
UI_TEXT = os.path.join(os.path.dirname(os.path.abspath(__file__)), "ui_text",
                       "en.json")


def _read(path):
    with io.open(path, encoding="utf-8") as f:
        return f.read()


def page() -> str:
    """The assembled index page. `</` is escaped inside the two inline
    scripts, so no text in them can close the tag early."""
    ui_text = json.dumps(json.loads(_read(UI_TEXT)), ensure_ascii=False)
    script = _read(os.path.join(STATIC, "app.js"))
    if "</script" in script.lower():
        raise ValueError("app.js may not contain a closing script tag")
    return (_read(os.path.join(STATIC, "index.html"))
            .replace("/*APP_CSS*/", _read(os.path.join(STATIC, "app.css")))
            .replace("/*UI_TEXT*/", ui_text.replace("</", "<\\/"))
            .replace("/*APP_JS*/", script))


# ⚠️ WHAT THE PANEL SAYS WHEN IT COULD NOT READ A DEVICE RANGE. Two of
# validate.py's rules compare a configured ceiling against the setpoint
# device's OWN reported range, and that range is only knowable by asking Home
# Assistant. When ESPHome is asleep or the entity does not exist yet the
# startup gate SKIPS those two rules rather than guessing - so the panel skips
# them too, and says so, because a green page that is green for a reason the
# operator cannot see is the exact failure this add-on keeps refusing to ship.
DEVICE_NOTE = (
    "%s did not report its power range, so two checks were skipped, here and "
    "at start. If they fail later, the add-on will not start then.")


def build_app(controller, selfcfg=None) -> web.Application:
    """The ingress app. `selfcfg` is injectable so a check can drive it.

    ⚠️ IT IS BUILT FROM THE CONTROLLER'S OWN SESSION AND TOKEN, not from a
    second `ClientSession`. `amain()` owns one session for the process and every
    Home Assistant call already goes through it; a second one here would be a
    second connection pool whose failures nothing reports.
    """
    if selfcfg is None:
        selfcfg = selfconfig.SelfConfig(controller.hass.session,
                                        controller.hass.token)
    entities = EntityCache(controller.hass)
    index_page = page()

    async def index(_request):
        return web.Response(text=index_page, content_type="text/html")

    async def status(_request):
        return web.json_response(controller.status_payload())

    async def action(request):
        try:
            body = await request.json()
        except ValueError:
            raise web.HTTPBadRequest(text="expected JSON")
        what = body.get("action")
        result = await controller.handle_action(what)
        if result is None:
            raise web.HTTPBadRequest(text=f"unknown action {what!r}")
        return web.json_response({"ok": True, "result": result})

    # --- UX-02: the configuration surface ---------------------------------
    async def config_index(_request):
        return web.Response(text=CONFIG_PAGE, content_type="text/html")

    async def _proposed(request):
        try:
            body = await request.json()
        except ValueError:
            raise web.HTTPBadRequest(text="expected JSON")
        options = body.get("options")
        if not isinstance(options, dict):
            raise web.HTTPBadRequest(text="expected an options object")
        return body, options

    async def config_model(request):
        """Everything the page needs to draw itself, from ONE Supervisor call.

        ⚠️ `running_differs` IS NOT COSMETIC. `controller.o` is the blob this
        PROCESS started with (`/data/options.json`); `info["options"]` is what
        the Supervisor has STORED and would apply at the next start. They differ
        exactly when somebody has saved and not restarted - here, or in the
        Configuration tab. Printing the difference is the only way an operator
        finds out that the page they are reading is not describing the running
        system, and it is also how an edit made on the other surface becomes
        visible on this one.
        """
        try:
            info = await selfcfg.info()
        except selfconfig.SupervisorUnavailable as err:
            _LOG.error("cannot read the add-on's own options: %s", err)
            return web.json_response({"error": str(err)}, status=502)
        options = info.get("options") or {}
        lang = str(request.query.get("lang", "en") or "en")[:8]
        model = field_model(info.get("schema") or [],
                            info.get("translations") or {}, lang)
        model.update({
            "options": options,
            "fingerprint": selfconfig.fingerprint(options),
            "running": controller.o,
            "running_differs": changed_keys(controller.o, options),
            "lang": lang,
            # UX-13 P1: the levies preset and its year, for the P2 Settings
            # screens, which show the year beside the region choice.
            "region": region_of(options),
        })
        return web.json_response(model)

    async def config_validate(request):
        """The SHIPPED validator, run against a proposed blob. Writes nothing.

        ⚠️ IT READS HOME ASSISTANT AND WRITES NOTHING ANYWHERE. The two
        device-range rules need `hass.limits()`, which is a GET of an entity's
        state. The page debounces, so a burst of typing is one call after the
        typing stops rather than one per keystroke.

        ⚠️ THE STRINGS ARE PASSED THROUGH UNTOUCHED. Not summarised, not
        renumbered, not mapped to a severity. validate.py's sentences are the
        product this card is delivering; anything this layer did to them would
        be a second opinion about a rule it does not own.
        """
        _body, options = await _proposed(request)
        notes = []
        problems, unread = await selfconfig.problems_and_ranges(
            options, controller.hass, notes=notes)
        by_key, unanchored = problems_by_field(problems, _keys_of(options))
        # UX-13: warnings and info beside the refusals. Never block a save.
        # The entity checks use the picker's cached list and never wait on HA.
        notes += config_notes(options, entities=entities.peek())
        payload = {"problems": problems, "by_key": by_key,
                   "unanchored": unanchored,
                   "notes": [n._asdict() for n in notes]}
        if unread:
            payload["device_note"] = DEVICE_NOTE % ", ".join(sorted(set(unread)))
        return web.json_response(payload)

    def _keys_of(options):
        # ⚠️ THE ANCHOR LIST IS THE KEYS OF THE BLOB UNDER TEST, and that is
        # sound only because the page posts the WHOLE blob it read - which is
        # `App.options`, the merge of config.yaml's defaults with the stored
        # ones, so every option key is in it. Nothing here types a key name;
        # see configui.problems_by_field() for what is done with them.
        return sorted(options)

    async def config_save(request):
        """Validate, compare-and-swap, write. Or refuse and write NOTHING."""
        body, options = await _proposed(request)
        expect = str(body.get("fingerprint") or "")
        try:
            result = await selfconfig.save(selfcfg, options, expect,
                                           hass=controller.hass)
        except selfconfig.SaveRefused as refused:
            if refused.kind == "stale":
                stored = refused.stored or {}
                return web.json_response(
                    {"kind": "stale", "changed": refused.changed,
                     "stored": stored,
                     # The page needs the CURRENT token to be able to save
                     # again after the operator has read the difference. That
                     # is not a force door: it takes a second, deliberate press
                     # made in front of what changed.
                     "fingerprint": selfconfig.fingerprint(stored)},
                    status=409)
            by_key, unanchored = problems_by_field(refused.problems,
                                                   _keys_of(options))
            return web.json_response(
                {"kind": "invalid", "problems": refused.problems,
                 "by_key": by_key, "unanchored": unanchored}, status=422)
        except selfconfig.SupervisorUnavailable as err:
            _LOG.error("saving options failed: %s", err)
            return web.json_response({"error": str(err)}, status=502)
        controller.log_event("configuration saved from the panel - "
                             "not applied until the add-on restarts",
                             hint=messages.hint("settings_saved"))
        return web.json_response({"ok": True, **result})

    async def config_restart(request):
        """Restart the add-on, at the operator's explicit request.

        ⚠️ THIS IS THE ONE ROUTE ON THIS SURFACE THAT COSTS ANYTHING. The
        wind-down commands 0 W on every inverter (`Controller.shutdown()`), so
        the request must carry the intent token; a reload, a retry or a stray
        POST cannot spend a control interruption. It restarts THIS ADD-ON and
        nothing else: no setpoint is written from here, and a latched failsafe
        is restored from the Store on the way back up rather than cleared.
        """
        try:
            body = await request.json()
        except ValueError:
            raise web.HTTPBadRequest(text="expected JSON")
        try:
            await selfcfg.restart(str(body.get("confirm") or ""))
        except selfconfig.NotConfirmed as err:
            return web.json_response({"error": str(err)}, status=400)
        except selfconfig.SupervisorUnavailable as err:
            _LOG.error("restart request failed: %s", err)
            return web.json_response({"error": str(err)}, status=502)
        controller.log_event("restart requested from the configuration panel",
                             hint=messages.hint("restart_requested"))
        return web.json_response({"ok": True})

    async def ha_entities(request):
        """UX-13: Home Assistant's entities for the picker. A read only, and
        never an error: when Home Assistant is down the list says so."""
        kind = str(request.query.get("kind", "") or "")[:16]
        return web.json_response(await entities.payload(kind))

    app = web.Application()
    app.add_routes([
        web.get("/", index),
        web.get("/status", status),
        web.post("/action", action),
        web.get("/config", config_index),
        web.get("/config/model", config_model),
        web.post("/config/validate", config_validate),
        web.post("/config/save", config_save),
        web.post("/config/restart", config_restart),
        web.get("/ha/entities", ha_entities),
    ])
    return app


def access_log():
    """UX-10: the page polls /status every few seconds, and aiohttp logs each
    request at INFO. That access log is kept for a DEBUG log level only."""
    return (logging.getLogger("aiohttp.access")
            if _LOG.isEnabledFor(logging.DEBUG) else None)


async def start(controller, port: int = 8099, selfcfg=None):
    runner = web.AppRunner(build_app(controller, selfcfg),
                           access_log=access_log())
    await runner.setup()
    site = web.TCPSite(runner, "0.0.0.0", port)
    await site.start()
    _LOG.info("ingress UI listening on :%s", port)
    return runner