#!/usr/bin/env python3

"""HTTP handler and route wiring for ani-cli-web."""

import json
import mimetypes
import os
import shutil
import traceback
from dataclasses import dataclass
from http.cookies import SimpleCookie
from http import HTTPStatus
from http.server import BaseHTTPRequestHandler
from pathlib import Path
from urllib.parse import parse_qs, unquote, urlencode, urlparse, urlunparse

from app_support import (
    ANI_CLI,
    APP_NAME,
    CLIENT_DISCONNECT_ERRORS,
    MAX_JSON_BODY_BYTES,
    MODE_CHOICES,
    VERSION,
    client_address_is_local,
    debug_enabled,
    debug_log,
    normalize_config,
    remote_access_allowed,
    remote_access_token_configured,
    remote_access_token_matches,
    send_discord_webhook_event,
)

@dataclass(frozen=True)
class HandlerContext:
    add_to_watchlist: object
    config_html: str
    ensure_runtime: object
    episode_list: object
    get_config_snapshot: object
    get_watchlist: object
    get_watchlist_refresh_status: object
    http_error: object
    index_html: str
    queue_html: str
    remove_from_watchlist: object
    runtime_state: object
    save_runtime_config: object
    search_anime: object
    test_discord_webhook_config: object
    thumbnail_file_path: object
    update_all_watchlist_statuses: object
    update_watchlist_category: object
    update_watchlist_status: object
    upload_watchlist_thumbnail: object
    watchlist_html: str


def build_handler_class(context):
    class ConfiguredHandler(Handler):
        handler_context = context

    return ConfiguredHandler


def dependency_status():
    checks = ["curl", "sed", "grep", "openssl", "fzf", "aria2c", "ffmpeg", "yt-dlp"]
    result = {name: bool(shutil.which(name)) for name in checks}
    result["ani-cli"] = bool(shutil.which(ANI_CLI) or (Path(ANI_CLI).exists() and os.access(ANI_CLI, os.X_OK)))
    return result


class Handler(BaseHTTPRequestHandler):
    server_version = "AniCliWeb/1.0"
    remote_token_cookie_name = "ani_cli_web_token"
    quiet_poll_paths = {"/api/queue", "/api/watchlist/refresh-status"}

    def _context(self):
        context = getattr(self, "handler_context", None) or getattr(type(self), "handler_context", None)
        if context is None:
            raise RuntimeError("Handler context is not configured.")
        return context

    def _runtime(self):
        context = Handler._context(self)
        context.ensure_runtime(start_workers=True)
        return context.runtime_state()

    def _effective_client_host(self):
        peer_host = self.client_address[0] if self.client_address else ""
        if not client_address_is_local(peer_host):
            return peer_host
        forwarded = (
            self.headers.get("X-Forwarded-For")
            or self.headers.get("x-forwarded-for")
            or self.headers.get("X-Real-IP")
            or self.headers.get("x-real-ip")
            or ""
        )
        if forwarded:
            first = str(forwarded).split(",", 1)[0].strip().strip("[]")
            if first:
                return first
        forwarded_header = str(self.headers.get("Forwarded") or self.headers.get("forwarded") or "").strip()
        if forwarded_header:
            for part in forwarded_header.split(";"):
                key, _, value = part.partition("=")
                if key.strip().lower() != "for":
                    continue
                candidate = value.strip().strip('"')
                if candidate.startswith("[") and "]" in candidate:
                    candidate = candidate[1 : candidate.index("]")]
                elif ":" in candidate and candidate.count(":") == 1:
                    candidate = candidate.split(":", 1)[0]
                candidate = candidate.strip()
                if candidate:
                    return candidate
        return peer_host

    def _remote_token(self):
        return (
            self.headers.get("X-AniCli-Web-Token")
            or self.headers.get("x-ani-cli-web-token")
            or Handler._bearer_token(self)
            or Handler._cookie_token(self)
            or Handler._query_token(self)
            or ""
        )

    def _bearer_token(self):
        header = str(self.headers.get("Authorization") or "").strip()
        if not header.startswith("Bearer "):
            return ""
        return header[len("Bearer ") :].strip()

    def _cookie_token(self):
        raw = str(self.headers.get("Cookie") or self.headers.get("cookie") or "").strip()
        if not raw:
            return ""
        try:
            cookie = SimpleCookie()
            cookie.load(raw)
        except Exception:
            return ""
        morsel = cookie.get(Handler.remote_token_cookie_name)
        if not morsel:
            return ""
        return morsel.value.strip()

    def _query_token(self):
        parsed = urlparse(self.path)
        params = parse_qs(parsed.query, keep_blank_values=True)
        for key in ("token", "remote_token"):
            values = params.get(key) or []
            for value in values:
                text = str(value).strip()
                if text:
                    return text
        return ""

    def _remote_cookie_bootstrap_response(self, parsed):
        client_host = Handler._effective_client_host(self)
        if client_address_is_local(client_host):
            return False
        if not remote_access_allowed() or not remote_access_token_configured():
            return False
        if Handler._cookie_token(self):
            return False
        token = Handler._query_token(self)
        if not token or not remote_access_token_matches(token):
            return False
        params = parse_qs(parsed.query, keep_blank_values=True)
        params.pop("token", None)
        params.pop("remote_token", None)
        query = urlencode(params, doseq=True)
        location = urlunparse(("", "", parsed.path or "/", "", query, ""))
        cookie = (
            f"{Handler.remote_token_cookie_name}={token}; "
            "Path=/; HttpOnly; SameSite=Lax"
        )
        Handler.write_response_bytes(
            self,
            b"",
            HTTPStatus.SEE_OTHER,
            {
                "Location": location,
                "Set-Cookie": cookie,
            },
        )
        return True

    def ensure_client_access(self):
        client_host = Handler._effective_client_host(self)
        if client_address_is_local(client_host):
            return
        if not remote_access_allowed():
            raise PermissionError(
                "Remote access is disabled. Set ANI_CLI_WEB_ALLOW_REMOTE=1 to allow non-local clients."
            )
        if not remote_access_token_configured():
            raise PermissionError(
                "Remote access requires ANI_CLI_WEB_REMOTE_TOKEN for non-local clients."
            )
        if not remote_access_token_matches(Handler._remote_token(self)):
            raise PermissionError("Remote access token missing or invalid.")

    def do_GET(self):
        parsed = urlparse(self.path)
        try:
            if Handler._remote_cookie_bootstrap_response(self, parsed):
                return
            self.ensure_client_access()
            if parsed.path == "/":
                self.html(Handler._context(self).index_html)
            elif parsed.path == "/queue":
                self.html(Handler._context(self).queue_html)
            elif parsed.path == "/config":
                self.html(Handler._context(self).config_html)
            elif parsed.path == "/watchlist":
                self.html(Handler._context(self).watchlist_html)
            elif parsed.path == "/api/config":
                self.json(Handler._context(self).get_config_snapshot())
            elif parsed.path == "/api/version":
                self.json({"name": APP_NAME, "version": VERSION})
            elif parsed.path == "/api/dependencies":
                self.json(dependency_status())
            elif parsed.path == "/api/search":
                runtime = Handler._runtime(self)
                config = runtime["config"]
                params = parse_qs(parsed.query)
                query = (params.get("q") or [""])[0].strip()
                mode = (params.get("mode") or [config["mode"]])[0].lower()
                if not query:
                    raise ValueError("Search query is required")
                if mode not in MODE_CHOICES:
                    raise ValueError("Mode must be sub or dub")
                self.json({"results": Handler._context(self).search_anime(query, mode)})
            elif parsed.path.startswith("/api/anime/") and parsed.path.endswith("/episodes"):
                runtime = Handler._runtime(self)
                config = runtime["config"]
                show_id = unquote(parsed.path[len("/api/anime/") : -len("/episodes")])
                params = parse_qs(parsed.query)
                mode = (params.get("mode") or [config["mode"]])[0].lower()
                if mode not in MODE_CHOICES:
                    raise ValueError("Mode must be sub or dub")
                self.json({"episodes": Handler._context(self).episode_list(show_id, mode)})
            elif parsed.path == "/api/queue":
                runtime = Handler._runtime(self)
                params = parse_qs(parsed.query)
                page = (params.get("page") or ["1"])[0]
                per_page = (params.get("per_page") or ["10"])[0]
                self.json(runtime["download_queue"].list(page=page, per_page=per_page))
            elif parsed.path.startswith("/api/watchlist/thumb/"):
                runtime = Handler._runtime(self)
                show_id = unquote(parsed.path[len("/api/watchlist/thumb/") :]).strip()
                debug_log("thumbnail.route.request", show_id=show_id, path=parsed.path, query=parsed.query)
                item = runtime["watchlist"].get(show_id)
                path = Handler._context(self).thumbnail_file_path(item.get("thumbnail_path"))
                if not path or not path.exists():
                    debug_log("thumbnail.route.miss", show_id=show_id, resolved_path=path)
                    self.error(HTTPStatus.NOT_FOUND, "Thumbnail not found")
                    return
                debug_log("thumbnail.route.hit", show_id=show_id, resolved_path=path)
                self.file(path)
            elif parsed.path in {"/api/watchlist", "/api/watchlist/get"}:
                Handler._runtime(self)
                params = parse_qs(parsed.query)
                page = (params.get("page") or ["1"])[0]
                per_page = (params.get("per_page") or ["30"])[0]
                category = (params.get("category") or [""])[0].strip().lower() or None
                self.json(Handler._context(self).get_watchlist(page=page, per_page=per_page, category=category))
            elif parsed.path == "/api/watchlist/refresh-status":
                Handler._runtime(self)
                self.json(Handler._context(self).get_watchlist_refresh_status())
            else:
                self.error(HTTPStatus.NOT_FOUND, "Not found")
        except Exception as exc:
            self.exception(exc)

    def do_POST(self):
        parsed = urlparse(self.path)
        try:
            self.ensure_client_access()
            if parsed.path == "/api/config":
                Handler.update_config(self, Handler.require_json_object(self, self.body_json()))
            elif parsed.path == "/api/config/webhook/test":
                payload = Handler.require_json_object(self, self.body_json())
                self.json(Handler._context(self).test_discord_webhook_config(payload))
            elif parsed.path == "/api/queue":
                runtime = Handler._runtime(self)
                self.json(runtime["download_queue"].add(self.body_json()), HTTPStatus.CREATED)
            elif parsed.path == "/api/queue/retry-failed":
                runtime = Handler._runtime(self)
                self.json(runtime["download_queue"].retry_all_failed())
            elif parsed.path == "/api/queue/clear-finished":
                runtime = Handler._runtime(self)
                self.json(runtime["download_queue"].clear_finished())
            elif parsed.path.startswith("/api/queue/"):
                runtime = Handler._runtime(self)
                parts = parsed.path.strip("/").split("/")
                if len(parts) != 4:
                    self.error(HTTPStatus.NOT_FOUND, "Not found")
                    return
                _, _, job_id, action = parts
                actions = {
                    "retry": runtime["download_queue"].retry,
                    "cancel": runtime["download_queue"].cancel,
                    "remove": runtime["download_queue"].remove,
                }
                if action not in actions:
                    self.error(HTTPStatus.NOT_FOUND, "Not found")
                    return
                self.json(actions[action](job_id))
            elif parsed.path in {"/api/watchlist", "/api/watchlist/add"}:
                Handler._runtime(self)
                result = Handler._context(self).add_to_watchlist(Handler.require_json_object(self, self.body_json()))
                status = HTTPStatus.CREATED if result.get("created") else HTTPStatus.OK
                self.json(result, status)
            elif parsed.path == "/api/watchlist/ensure-thumbnails":
                runtime = Handler._runtime(self)
                payload = Handler.require_json_object(self, self.body_json())
                self.json(
                    runtime["watchlist"].ensure_thumbnails(
                        Handler.optional_list_field(self, payload, "show_ids") or [],
                        limit=payload.get("limit", 6),
                        force=Handler.optional_bool_field(self, payload, "force", default=False),
                    )
                )
            elif parsed.path == "/api/watchlist/update-status":
                Handler._runtime(self)
                payload = Handler.require_fields(self, self.body_json(), "show_id")
                self.json(Handler._context(self).update_watchlist_status(payload["show_id"], payload.get("mode")))
            elif parsed.path == "/api/watchlist/update-category":
                Handler._runtime(self)
                payload = Handler.require_fields(self, self.body_json(), "show_id")
                self.json(Handler._context(self).update_watchlist_category(payload["show_id"], payload.get("category")))
            elif parsed.path == "/api/watchlist/update-all":
                Handler._runtime(self)
                result = Handler._context(self).update_all_watchlist_statuses()
                status = HTTPStatus.ACCEPTED if result.get("created") else HTTPStatus.OK
                self.json(result, status)
            elif parsed.path == "/api/watchlist/remove":
                Handler._runtime(self)
                payload = Handler.require_fields(self, self.body_json(), "show_id")
                self.json(Handler._context(self).remove_from_watchlist(payload["show_id"]))
            elif parsed.path == "/api/watchlist/upload-thumbnail":
                Handler._runtime(self)
                payload = Handler.require_fields(self, self.body_json(), "show_id", "data_url")
                self.json(Handler._context(self).upload_watchlist_thumbnail(payload))
            else:
                self.error(HTTPStatus.NOT_FOUND, "Not found")
        except Exception as exc:
            self.exception(exc)

    def update_config(self, payload):
        config = normalize_config(payload)
        Path(config["download_dir"]).expanduser().mkdir(parents=True, exist_ok=True)
        context = Handler._context(self)
        context.save_runtime_config(config)
        self.json(context.get_config_snapshot())

    def require_fields(self, payload, *names):
        payload = Handler.require_json_object(self, payload)
        missing = [name for name in names if not str(payload.get(name) or "").strip()]
        if missing:
            if len(missing) == 1:
                raise ValueError(f"Missing required field: {missing[0]}")
            raise ValueError(f"Missing required fields: {', '.join(missing)}")
        return payload

    def require_json_object(self, payload):
        if not isinstance(payload, dict):
            raise ValueError("Expected a JSON object")
        return payload

    def optional_list_field(self, payload, name):
        payload = Handler.require_json_object(self, payload)
        if name not in payload or payload.get(name) is None:
            return None
        value = payload.get(name)
        if not isinstance(value, list):
            raise ValueError(f"Field '{name}' must be a JSON array")
        return value

    def optional_bool_field(self, payload, name, default=False):
        payload = Handler.require_json_object(self, payload)
        if name not in payload or payload.get(name) is None:
            return default
        value = payload.get(name)
        if isinstance(value, bool):
            return value
        if isinstance(value, str):
            normalized = value.strip().lower()
            if normalized in {"1", "true", "yes", "on"}:
                return True
            if normalized in {"0", "false", "no", "off"}:
                return False
        raise ValueError(f"Field '{name}' must be a boolean")

    def body_json(self):
        try:
            length = int(self.headers.get("Content-Length", "0") or "0")
        except ValueError as exc:
            raise ValueError("Invalid Content-Length header") from exc
        if length < 0:
            raise ValueError("Invalid Content-Length header")
        if length > MAX_JSON_BODY_BYTES:
            raise Handler._context(self).http_error(HTTPStatus.REQUEST_ENTITY_TOO_LARGE, "Request body too large.")
        raw_bytes = self.rfile.read(length) if length else b"{}"
        if len(raw_bytes) > MAX_JSON_BODY_BYTES:
            raise Handler._context(self).http_error(HTTPStatus.REQUEST_ENTITY_TOO_LARGE, "Request body too large.")
        try:
            raw = raw_bytes.decode("utf-8")
        except UnicodeDecodeError as exc:
            raise ValueError("Request body must be valid UTF-8 JSON.") from exc
        try:
            return json.loads(raw)
        except json.JSONDecodeError as exc:
            raise ValueError("Invalid JSON body") from exc

    def html(self, content):
        data = content.encode("utf-8")
        self.write_response_bytes(data, HTTPStatus.OK, {"Content-Type": "text/html; charset=utf-8"})

    def file(self, path):
        payload = Path(path).read_bytes()
        content_type = mimetypes.guess_type(str(path))[0] or "application/octet-stream"
        debug_log("file.serve", path=path, content_type=content_type, bytes=len(payload))
        self.write_response_bytes(
            payload,
            HTTPStatus.OK,
            {
                "Content-Type": content_type,
                "Cache-Control": "public, max-age=86400",
            },
        )

    def json(self, payload, status=HTTPStatus.OK):
        data = json.dumps(payload).encode("utf-8")
        self.write_response_bytes(data, status, {"Content-Type": "application/json"})

    def write_response_bytes(self, payload, status, headers):
        try:
            self.send_response(status)
            for key, value in headers.items():
                self.send_header(key, value)
            self.send_header("Content-Length", str(len(payload)))
            self.end_headers()
            self.wfile.write(payload)
        except CLIENT_DISCONNECT_ERRORS:
            return

    def error(self, status, message):
        try:
            self.json({"error": message}, status)
        except CLIENT_DISCONNECT_ERRORS:
            return

    def exception(self, exc):
        if isinstance(exc, CLIENT_DISCONNECT_ERRORS):
            return
        if isinstance(exc, Handler._context(self).http_error):
            self.error(exc.status, exc.message)
        elif isinstance(exc, KeyError):
            self.error(HTTPStatus.NOT_FOUND, str(exc).strip("'"))
        elif isinstance(exc, PermissionError):
            self.error(HTTPStatus.FORBIDDEN, str(exc))
        elif isinstance(exc, ValueError):
            self.error(HTTPStatus.BAD_REQUEST, str(exc))
        else:
            if debug_enabled():
                debug_log("handler.exception", path=getattr(self, "path", ""), error=exc)
                traceback.print_exc()
            else:
                debug_log("handler.exception", path=getattr(self, "path", ""), error=exc)
            try:
                send_discord_webhook_event(
                    Handler._context(self).get_config_snapshot(),
                    "runtime_error",
                    {
                        "source": "http_handler",
                        "error": str(exc),
                        "details": f"path={getattr(self, 'path', '')}",
                    },
                )
            except Exception as notify_exc:
                debug_log("discord_webhook.runtime_error_failed", source="http_handler", error=notify_exc)
            self.error(HTTPStatus.INTERNAL_SERVER_ERROR, "Internal server error.")

    def log_message(self, fmt, *args):
        parsed = urlparse(getattr(self, "path", "") or "")
        if self.command == "GET" and parsed.path in Handler.quiet_poll_paths:
            return
        print(f"{self.address_string()} - {fmt % args}")


def server_host():
    return os.environ.get("ANI_CLI_WEB_HOST", "127.0.0.1").strip() or "127.0.0.1"


def server_port():
    raw = str(os.environ.get("ANI_CLI_WEB_PORT", "8421")).strip() or "8421"
    try:
        port = int(raw, 10)
    except ValueError as exc:
        raise ValueError("ANI_CLI_WEB_PORT must be a valid integer") from exc
    if not 1 <= port <= 65535:
        raise ValueError("ANI_CLI_WEB_PORT must be between 1 and 65535")
    return port