from __future__ import annotations

import html
import json
import os
import re
import shutil
from datetime import datetime, timezone
from pathlib import Path
from typing import Any

NANOBOT_WORKSPACE = Path(os.getenv("NANOBOT_WORKSPACE", str(Path.home() / ".nanobot"))).expanduser()
CARDS_ROOT = NANOBOT_WORKSPACE / "cards"
CARD_INSTANCES_DIR = CARDS_ROOT / "instances"
CARD_TEMPLATES_DIR = CARDS_ROOT / "templates"
TEMPLATES_CONTEXT_PATH = NANOBOT_WORKSPACE / "CARD_TEMPLATES.md"
MAX_TEMPLATES_IN_PROMPT = 12
MAX_TEMPLATE_HTML_CHARS = 4000
_INVALID_TEMPLATE_KEY_CHARS = re.compile(r"[^a-z0-9_-]+")
_CARD_ID_PATTERN = re.compile(r"^[a-zA-Z0-9_-]{1,128}$")
_CARD_LANE_ORDER = {"attention": 0, "work": 1, "context": 2, "history": 3}
_CARD_STATE_ORDER = {"active": 0, "stale": 1, "resolved": 2, "superseded": 3, "archived": 4}


def ensure_card_store_dirs() -> None:
    CARD_INSTANCES_DIR.mkdir(parents=True, exist_ok=True)
    CARD_TEMPLATES_DIR.mkdir(parents=True, exist_ok=True)


def _normalize_template_key(raw: str) -> str:
    key = _INVALID_TEMPLATE_KEY_CHARS.sub("-", raw.strip().lower()).strip("-")
    return key[:64]


def _normalize_card_id(raw: str) -> str:
    card_id = raw.strip()
    return card_id if _CARD_ID_PATTERN.fullmatch(card_id) else ""


def _card_instance_dir(card_id: str) -> Path | None:
    card_id_clean = _normalize_card_id(card_id)
    if not card_id_clean:
        return None
    return CARD_INSTANCES_DIR / card_id_clean


def _card_meta_path(card_id: str) -> Path | None:
    instance_dir = _card_instance_dir(card_id)
    if instance_dir is None:
        return None
    return instance_dir / "card.json"


def _card_state_path(card_id: str) -> Path | None:
    instance_dir = _card_instance_dir(card_id)
    if instance_dir is None:
        return None
    return instance_dir / "state.json"


def _parse_iso_datetime(raw: str) -> datetime | None:
    value = raw.strip()
    if not value:
        return None
    try:
        parsed = datetime.fromisoformat(value.replace("Z", "+00:00"))
    except ValueError:
        return None
    if parsed.tzinfo is None:
        parsed = parsed.replace(tzinfo=timezone.utc)
    return parsed.astimezone(timezone.utc)


def _coerce_card_record(raw: dict[str, Any]) -> dict[str, Any] | None:
    card_id = _normalize_card_id(str(raw.get("id", "")))
    if not card_id:
        return None

    kind = str(raw.get("kind", "text") or "text").strip().lower()
    if kind not in {"text", "question"}:
        kind = "text"

    lane = str(raw.get("lane", "context") or "context").strip().lower()
    if lane not in _CARD_LANE_ORDER:
        lane = "context"

    state = str(raw.get("state", "active") or "active").strip().lower()
    if state not in _CARD_STATE_ORDER:
        state = "active"

    try:
        priority = int(raw.get("priority", 50))
    except (TypeError, ValueError):
        priority = 50
    priority = max(0, min(priority, 100))

    raw_choices = raw.get("choices", [])
    choices = [str(choice) for choice in raw_choices] if isinstance(raw_choices, list) else []
    raw_template_state = raw.get("template_state", {})
    template_state = raw_template_state if isinstance(raw_template_state, dict) else {}

    return {
        "id": card_id,
        "kind": kind,
        "title": str(raw.get("title", "")),
        "content": str(raw.get("content", "")),
        "question": str(raw.get("question", "")),
        "choices": choices,
        "response_value": str(raw.get("response_value", "")),
        "slot": str(raw.get("slot", "")),
        "lane": lane,
        "priority": priority,
        "state": state,
        "template_key": str(raw.get("template_key", "")),
        "template_state": template_state,
        "context_summary": str(raw.get("context_summary", "")),
        "chat_id": str(raw.get("chat_id", "web") or "web"),
        "snooze_until": str(raw.get("snooze_until", "") or ""),
        "created_at": str(raw.get("created_at", "")),
        "updated_at": str(raw.get("updated_at", "")),
    }


def _json_script_text(payload: dict[str, Any]) -> str:
    return json.dumps(payload, ensure_ascii=False).replace("</", "<\\/")


def _template_dir(template_key: str) -> Path:
    return CARD_TEMPLATES_DIR / template_key


def _template_html_path(template_key: str) -> Path:
    return _template_dir(template_key) / "template.html"


def _template_meta_path(template_key: str) -> Path:
    return _template_dir(template_key) / "manifest.json"


def _read_template_meta(template_key: str) -> dict[str, Any]:
    meta_path = _template_meta_path(template_key)
    try:
        meta = json.loads(meta_path.read_text(encoding="utf-8"))
        return meta if isinstance(meta, dict) else {}
    except Exception:
        return {}


def _materialize_card_content(card: dict[str, Any]) -> str:
    if card.get("kind") != "text":
        return str(card.get("content", ""))

    template_key = str(card.get("template_key", "")).strip()
    if not template_key:
        return str(card.get("content", ""))

    html_path = _template_html_path(template_key)
    try:
        template_html = html_path.read_text(encoding="utf-8")
    except Exception:
        return (
            '<div style="padding:16px;border:1px solid #fecaca;border-radius:12px;'
            'background:#fef2f2;color:#991b1b;font:600 14px/1.4 system-ui,sans-serif;">'
            f"Missing template: {html.escape(template_key)}"
            "</div>"
        )

    state_payload = card.get("template_state", {})
    if not isinstance(state_payload, dict):
        state_payload = {}

    card_id = html.escape(str(card.get("id", "")))
    safe_template_key = html.escape(template_key)
    return (
        f'<div data-nanobot-card-root data-card-id="{card_id}" data-template-key="{safe_template_key}">'
        f'<script type="application/json" data-card-state>{_json_script_text(state_payload)}</script>'
        f"{template_html}"
        "</div>"
    )


def _load_card(card_id: str) -> dict[str, Any] | None:
    meta_path = _card_meta_path(card_id)
    if meta_path is None or not meta_path.exists():
        return None
    try:
        raw = json.loads(meta_path.read_text(encoding="utf-8"))
    except Exception:
        return None
    if not isinstance(raw, dict):
        return None

    state_path = _card_state_path(card_id)
    if state_path is not None and state_path.exists():
        try:
            raw_state = json.loads(state_path.read_text(encoding="utf-8"))
        except Exception:
            raw_state = {}
        if isinstance(raw_state, dict):
            raw["template_state"] = raw_state

    card = _coerce_card_record(raw)
    if card is None:
        return None

    card["content"] = _materialize_card_content(card)
    return card


def _write_card(card: dict[str, Any]) -> dict[str, Any] | None:
    normalized = _coerce_card_record(card)
    if normalized is None:
        return None

    now = datetime.now(timezone.utc).isoformat()
    existing = _load_card(normalized["id"])
    if existing is not None:
        normalized["created_at"] = existing.get("created_at") or normalized.get("created_at") or now
    else:
        normalized["created_at"] = normalized.get("created_at") or now
    normalized["updated_at"] = normalized.get("updated_at") or now

    instance_dir = _card_instance_dir(normalized["id"])
    meta_path = _card_meta_path(normalized["id"])
    state_path = _card_state_path(normalized["id"])
    if instance_dir is None or meta_path is None or state_path is None:
        return None

    instance_dir.mkdir(parents=True, exist_ok=True)

    template_state = normalized.pop("template_state", {})
    meta_path.write_text(
        json.dumps(normalized, indent=2, ensure_ascii=False) + "\n",
        encoding="utf-8",
    )
    if normalized["kind"] == "text":
        state_path.write_text(
            json.dumps(
                template_state if isinstance(template_state, dict) else {},
                indent=2,
                ensure_ascii=False,
            )
            + "\n",
            encoding="utf-8",
        )
    else:
        state_path.unlink(missing_ok=True)

    return _load_card(normalized["id"])


def _sort_cards(cards: list[dict[str, Any]]) -> list[dict[str, Any]]:
    return sorted(
        cards,
        key=lambda item: (
            _CARD_LANE_ORDER.get(str(item.get("lane", "context")), 99),
            _CARD_STATE_ORDER.get(str(item.get("state", "active")), 99),
            -int(item.get("priority", 0) or 0),
            str(item.get("updated_at", "")),
            str(item.get("created_at", "")),
        ),
        reverse=False,
    )


def _load_cards(chat_id: str | None = None) -> list[dict[str, Any]]:
    ensure_card_store_dirs()
    cards: list[dict[str, Any]] = []
    now = datetime.now(timezone.utc)
    for instance_dir in CARD_INSTANCES_DIR.iterdir():
        if not instance_dir.is_dir():
            continue
        card = _load_card(instance_dir.name)
        if card is None:
            continue
        if chat_id is not None and str(card.get("chat_id", "web") or "web") != chat_id:
            continue
        if card.get("state") == "archived":
            continue
        snooze_until = _parse_iso_datetime(str(card.get("snooze_until", "") or ""))
        if snooze_until is not None and snooze_until > now:
            continue
        cards.append(card)
    return _sort_cards(cards)


def _find_card_by_slot(slot: str, *, chat_id: str) -> dict[str, Any] | None:
    target_slot = slot.strip()
    if not target_slot:
        return None
    for card in _load_cards():
        if str(card.get("chat_id", "")).strip() != chat_id:
            continue
        if str(card.get("slot", "")).strip() == target_slot:
            return card
    return None


def _persist_card(card: dict[str, Any]) -> dict[str, Any] | None:
    normalized = _coerce_card_record(card)
    if normalized is None:
        return None

    existing_same_slot = None
    slot = str(normalized.get("slot", "")).strip()
    chat_id = str(normalized.get("chat_id", "web") or "web")
    if slot:
        existing_same_slot = _find_card_by_slot(slot, chat_id=chat_id)

    if existing_same_slot is not None and existing_same_slot["id"] != normalized["id"]:
        superseded = dict(existing_same_slot)
        superseded["state"] = "superseded"
        superseded["updated_at"] = datetime.now(timezone.utc).isoformat()
        _write_card(superseded)

    return _write_card(normalized)


def _delete_card(card_id: str) -> bool:
    instance_dir = _card_instance_dir(card_id)
    if instance_dir is None or not instance_dir.exists():
        return False
    shutil.rmtree(instance_dir, ignore_errors=True)
    return True


def _delete_cards_for_chat(chat_id: str) -> int:
    ensure_card_store_dirs()
    removed = 0
    for instance_dir in CARD_INSTANCES_DIR.iterdir():
        if not instance_dir.is_dir():
            continue
        card = _load_card(instance_dir.name)
        if card is None:
            continue
        if str(card.get("chat_id", "web") or "web") != chat_id:
            continue
        if _delete_card(instance_dir.name):
            removed += 1
    return removed


def _list_templates(limit: int | None = None) -> list[dict[str, Any]]:
    ensure_card_store_dirs()
    templates: list[dict[str, Any]] = []

    for template_dir in CARD_TEMPLATES_DIR.iterdir():
        if not template_dir.is_dir():
            continue
        key = _normalize_template_key(template_dir.name)
        if not key:
            continue

        html_path = _template_html_path(key)
        if not html_path.exists():
            continue
        try:
            content = html_path.read_text(encoding="utf-8")
        except Exception:
            continue

        stat = html_path.stat()
        meta = _read_template_meta(key)
        if bool(meta.get("deprecated")):
            continue
        created_at = str(
            meta.get("created_at")
            or datetime.fromtimestamp(stat.st_ctime, timezone.utc).isoformat()
        )
        updated_at = str(
            meta.get("updated_at")
            or datetime.fromtimestamp(stat.st_mtime, timezone.utc).isoformat()
        )
        templates.append(
            {
                "id": key,
                "key": key,
                "title": str(meta.get("title", "")),
                "content": content,
                "notes": str(meta.get("notes", "")),
                "example_state": meta.get("example_state", {}),
                "created_at": created_at,
                "updated_at": updated_at,
                "file_url": f"/card-templates/{key}/template.html",
            }
        )

    templates.sort(key=lambda item: item["updated_at"], reverse=True)
    if limit is not None:
        return templates[: max(0, limit)]
    return templates


def _render_templates_markdown(rows: list[dict[str, Any]]) -> str:
    lines = [
        "# Card Templates",
        "",
        "These are user-approved template layouts for `mcp_display_render_card` cards.",
        "Each card instance should provide a `template_key` and a `template_state` JSON object.",
        "Use a matching template when the request intent fits.",
        "Do not rewrite the HTML layout when an existing template already fits; fill the template_state instead.",
        "",
    ]
    for row in rows:
        key = str(row.get("key", "")).strip() or "unnamed"
        title = str(row.get("title", "")).strip() or "(untitled)"
        notes = str(row.get("notes", "")).strip() or "(no usage notes)"
        content = str(row.get("content", "")).strip()
        example_state = row.get("example_state", {})
        if len(content) > MAX_TEMPLATE_HTML_CHARS:
            content = content[:MAX_TEMPLATE_HTML_CHARS] + "\n<!-- truncated -->"
        html_lines = [f"    {line}" for line in content.splitlines()] if content else ["    "]
        state_text = (
            json.dumps(example_state, indent=2, ensure_ascii=False)
            if isinstance(example_state, dict)
            else "{}"
        )
        state_lines = [f"    {line}" for line in state_text.splitlines()]
        lines.extend(
            [
                f"## {key}",
                f"- Title: {title}",
                f"- Usage: {notes}",
                "- Example State:",
                *state_lines,
                "- HTML:",
                *html_lines,
                "",
            ]
        )
    return "\n".join(lines).rstrip() + "\n"


def _sync_templates_context_file() -> None:
    try:
        ensure_card_store_dirs()
        rows = _list_templates(limit=MAX_TEMPLATES_IN_PROMPT)
        if not rows:
            TEMPLATES_CONTEXT_PATH.unlink(missing_ok=True)
            return
        TEMPLATES_CONTEXT_PATH.parent.mkdir(parents=True, exist_ok=True)
        TEMPLATES_CONTEXT_PATH.write_text(_render_templates_markdown(rows), encoding="utf-8")
    except Exception:
        return


normalize_template_key = _normalize_template_key
normalize_card_id = _normalize_card_id
parse_iso_datetime = _parse_iso_datetime
coerce_card_record = _coerce_card_record
template_dir = _template_dir
template_html_path = _template_html_path
template_meta_path = _template_meta_path
read_template_meta = _read_template_meta
load_card = _load_card
load_cards = _load_cards
write_card = _write_card
persist_card = _persist_card
delete_card = _delete_card
delete_cards_for_chat = _delete_cards_for_chat
list_templates = _list_templates
sync_templates_context_file = _sync_templates_context_file
json_script_text = _json_script_text

__all__ = [
    "CARD_INSTANCES_DIR",
    "CARD_TEMPLATES_DIR",
    "NANOBOT_WORKSPACE",
    "TEMPLATES_CONTEXT_PATH",
    "coerce_card_record",
    "delete_card",
    "delete_cards_for_chat",
    "ensure_card_store_dirs",
    "json_script_text",
    "list_templates",
    "load_card",
    "load_cards",
    "normalize_card_id",
    "normalize_template_key",
    "parse_iso_datetime",
    "persist_card",
    "read_template_meta",
    "sync_templates_context_file",
    "template_dir",
    "template_html_path",
    "template_meta_path",
    "write_card",
]