"""Joplin Data API client for importing notes into Joplin desktop."""

import json
import logging
import os
import re
from pathlib import Path
from typing import Any

import requests

logger = logging.getLogger(__name__)

# HTTP timeout for regular API calls (seconds). Notes can be large Markdown
# files so we allow more time than a typical JSON API call.
# Override with JOPLIN_REQUEST_TIMEOUT env var if you have very large conversations.
_REQUEST_TIMEOUT: int = int(os.getenv("JOPLIN_REQUEST_TIMEOUT", "30"))


class JoplinError(Exception):
    """Raised when the Joplin API returns an error or is unreachable."""


class JoplinClient:
    """HTTP client for the Joplin local REST API (Web Clipper service).

    Requires Joplin desktop to be running with the Web Clipper service enabled.
    Get your API token from: Joplin → Tools → Options → Web Clipper.

    Args:
        base_url: Joplin API base URL (default: http://localhost:41184).
        token: API authorization token from Joplin Web Clipper settings.
    """

    def __init__(self, base_url: str, token: str) -> None:
        self._base_url = base_url.rstrip("/")
        self._token = token
        # In-memory cache: (parent_id | None, title) → folder ID
        self._notebook_cache: dict[tuple[str | None, str], str] = {}
        self._notebooks_loaded = False
        logger.debug("[joplin] Client initialised with base_url=%s", self._base_url)

    # ------------------------------------------------------------------
    # Connectivity
    # ------------------------------------------------------------------

    def ping(self) -> bool:
        """Return True if the Joplin API is reachable and responding.

        Note: /ping does not require authentication. A successful ping only
        confirms Joplin is running — not that the token is valid. Call
        ``validate_token()`` to confirm authentication separately.

        Raises:
            JoplinError: If the API returns an unexpected non-connection error.
        """
        url = f"{self._base_url}/ping"
        logger.debug("[joplin] GET %s", url)
        try:
            resp = requests.get(url, timeout=5)
            resp.raise_for_status()
            ok = "JoplinClipperServer" in resp.text
            logger.debug("[joplin] ping → %s (body: %r)", "OK" if ok else "unexpected response", resp.text[:80])
            return ok
        except requests.exceptions.ConnectionError:
            logger.debug("[joplin] ping → connection refused at %s", url)
            return False
        except requests.exceptions.Timeout:
            logger.debug("[joplin] ping → timed out after 5s at %s", url)
            return False
        except requests.exceptions.RequestException as e:
            raise JoplinError(f"Joplin ping failed: {e}") from e

    def validate_token(self) -> None:
        """Verify the API token is accepted by Joplin.

        Does a minimal authenticated call (GET /folders?limit=1) and raises
        ``JoplinError`` if authentication fails.

        Raises:
            JoplinError: If the token is rejected (401) or Joplin is unreachable.
        """
        logger.debug("[joplin] Validating API token…")
        self._get("/folders", params={"limit": 1, "fields": "id"})
        logger.debug("[joplin] Token validated OK")

    # ------------------------------------------------------------------
    # Notebooks (folders)
    # ------------------------------------------------------------------

    def list_notebooks(self) -> list[dict]:
        """Return all Joplin notebooks (folders), handling pagination.

        Returns:
            List of folder dicts with at least ``id``, ``title``, and ``parent_id`` keys.
        """
        results: list[dict] = []
        page = 1
        while True:
            logger.debug("[joplin] GET /folders page=%d", page)
            resp = self._get("/folders", params={"page": page, "fields": "id,title,parent_id"})
            items = resp.get("items", [])
            results.extend(items)
            logger.debug("[joplin] /folders page=%d → %d items, has_more=%s", page, len(items), resp.get("has_more"))
            if not resp.get("has_more"):
                break
            page += 1
        return results

    def get_or_create_notebook(self, title: str, parent_id: str | None = None) -> str:
        """Return the Joplin folder ID for ``title`` under ``parent_id``, creating if needed.

        Args:
            title: Notebook display name.
            parent_id: ID of the parent folder, or None for a root notebook.

        Returns:
            Joplin folder ID string.
        """
        if not self._notebooks_loaded:
            self._load_notebook_cache()

        key = (parent_id, title)
        if key in self._notebook_cache:
            folder_id = self._notebook_cache[key]
            logger.debug("[joplin] Notebook cache hit: %r (parent=%s) → %s", title, parent_id, folder_id)
            return folder_id

        # Not found — create it
        logger.info("[joplin] Creating notebook: %r (parent=%s)", title, parent_id)
        data: dict = {"title": title}
        if parent_id:
            data["parent_id"] = parent_id
        resp = self._post("/folders", data)
        folder_id = resp["id"]
        self._notebook_cache[key] = folder_id
        logger.debug("[joplin] Notebook created: %r → %s", title, folder_id)
        return folder_id

    def get_or_create_notebook_path(self, path: list[str]) -> str:
        """Ensure a nested notebook path exists and return the leaf folder ID.

        Creates intermediate notebooks as needed.

        Args:
            path: Ordered list of notebook names, e.g. ["AI-ChatGPT", "No Project"].

        Returns:
            Joplin folder ID of the deepest (leaf) notebook.
        """
        parent_id: str | None = None
        for name in path:
            parent_id = self.get_or_create_notebook(name, parent_id)
        assert parent_id is not None
        return parent_id

    # ------------------------------------------------------------------
    # Notes
    # ------------------------------------------------------------------

    def create_note(self, title: str, body: str, parent_id: str) -> str:
        """Create a new note in the specified notebook.

        Args:
            title: Note title.
            body: Note body (Markdown).
            parent_id: Notebook (folder) ID.

        Returns:
            ID of the created note.
        """
        logger.debug(
            "[joplin] Creating note: %r in notebook %s (%d chars)",
            title, parent_id, len(body),
        )
        resp = self._post("/notes", {"title": title, "body": body, "parent_id": parent_id})
        note_id = resp["id"]
        logger.info("[joplin] Note created: %r → %s", title, note_id)
        return note_id

    def update_note(self, note_id: str, title: str, body: str) -> None:
        """Update the title and body of an existing note.

        Args:
            note_id: Joplin note ID.
            title: New note title.
            body: New note body (Markdown).
        """
        logger.debug(
            "[joplin] Updating note %s: %r (%d chars)",
            note_id, title, len(body),
        )
        self._put(f"/notes/{note_id}", {"title": title, "body": body})
        logger.info("[joplin] Note updated: %r (%s)", title, note_id)

    # ------------------------------------------------------------------
    # Resources (embedded media)
    # ------------------------------------------------------------------

    def create_resource(self, file_path: "Path", title: str | None = None) -> str:
        """Upload a local file as a Joplin resource and return its ID.

        Joplin's ``POST /resources`` is multipart: a ``data`` file part plus a
        ``props`` JSON part. The returned ID is referenced from note bodies as
        ``:/<id>``.
        """
        url = f"{self._base_url}/resources"
        props = json.dumps({"title": title or file_path.name})
        logger.debug("[joplin] POST /resources (%s)", file_path.name)
        try:
            with file_path.open("rb") as fh:
                resp = requests.post(
                    url,
                    params={"token": self._token},
                    files={
                        "data": (file_path.name, fh),
                        "props": (None, props),
                    },
                    timeout=_REQUEST_TIMEOUT,
                )
            resp.raise_for_status()
            resource_id = resp.json()["id"]
            logger.info("[joplin] Resource created: %s → %s", file_path.name, resource_id)
            return resource_id
        except requests.exceptions.ConnectionError as e:
            raise JoplinError(
                "Cannot connect to Joplin. Is Joplin desktop running with Web Clipper enabled?"
            ) from e
        except requests.exceptions.Timeout as e:
            raise JoplinError(_timeout_message("POST", "/resources")) from e
        except requests.exceptions.HTTPError as e:
            raise JoplinError(_http_error_message("POST", "/resources", e)) from e
        except (requests.exceptions.RequestException, KeyError, OSError) as e:
            raise JoplinError(f"Joplin resource upload failed for {file_path.name}: {e}") from e

    # ------------------------------------------------------------------
    # HTTP helpers
    # ------------------------------------------------------------------

    def _get(self, path: str, params: dict | None = None) -> dict[str, Any]:
        url = f"{self._base_url}{path}"
        query = {"token": self._token, **(params or {})}
        logger.debug("[joplin] GET %s params=%s", path, {k: v for k, v in (params or {}).items()})
        try:
            resp = requests.get(url, params=query, timeout=_REQUEST_TIMEOUT)
            logger.debug("[joplin] GET %s → HTTP %d", path, resp.status_code)
            resp.raise_for_status()
            return resp.json()
        except requests.exceptions.ConnectionError as e:
            raise JoplinError(
                "Cannot connect to Joplin. Is Joplin desktop running with Web Clipper enabled?"
            ) from e
        except requests.exceptions.Timeout as e:
            raise JoplinError(_timeout_message("GET", path)) from e
        except requests.exceptions.HTTPError as e:
            raise JoplinError(_http_error_message("GET", path, e)) from e
        except requests.exceptions.RequestException as e:
            raise JoplinError(f"Joplin GET {path} failed: {e}") from e

    def _post(self, path: str, data: dict) -> dict[str, Any]:
        url = f"{self._base_url}{path}"
        logger.debug("[joplin] POST %s", path)
        try:
            resp = requests.post(url, params={"token": self._token}, json=data, timeout=_REQUEST_TIMEOUT)
            logger.debug("[joplin] POST %s → HTTP %d", path, resp.status_code)
            resp.raise_for_status()
            return resp.json()
        except requests.exceptions.ConnectionError as e:
            raise JoplinError(
                "Cannot connect to Joplin. Is Joplin desktop running with Web Clipper enabled?"
            ) from e
        except requests.exceptions.Timeout as e:
            raise JoplinError(_timeout_message("POST", path)) from e
        except requests.exceptions.HTTPError as e:
            raise JoplinError(_http_error_message("POST", path, e)) from e
        except requests.exceptions.RequestException as e:
            raise JoplinError(f"Joplin POST {path} failed: {e}") from e

    def _put(self, path: str, data: dict) -> dict[str, Any]:
        url = f"{self._base_url}{path}"
        logger.debug("[joplin] PUT %s", path)
        try:
            resp = requests.put(url, params={"token": self._token}, json=data, timeout=_REQUEST_TIMEOUT)
            logger.debug("[joplin] PUT %s → HTTP %d", path, resp.status_code)
            resp.raise_for_status()
            return resp.json()
        except requests.exceptions.ConnectionError as e:
            raise JoplinError(
                "Cannot connect to Joplin. Is Joplin desktop running with Web Clipper enabled?"
            ) from e
        except requests.exceptions.Timeout as e:
            raise JoplinError(_timeout_message("PUT", path)) from e
        except requests.exceptions.HTTPError as e:
            raise JoplinError(_http_error_message("PUT", path, e)) from e
        except requests.exceptions.RequestException as e:
            raise JoplinError(f"Joplin PUT {path} failed: {e}") from e

    def _load_notebook_cache(self) -> None:
        logger.debug("[joplin] Loading notebook list from Joplin…")
        notebooks = self.list_notebooks()
        self._notebook_cache = {
            (nb.get("parent_id") or None, nb["title"]): nb["id"]
            for nb in notebooks
        }
        self._notebooks_loaded = True
        logger.debug("[joplin] Notebook cache loaded: %d notebooks", len(self._notebook_cache))
        for (parent_id, title), folder_id in self._notebook_cache.items():
            logger.debug("[joplin]   (%s) %r → %s", parent_id or "root", title, folder_id)


# ------------------------------------------------------------------
# Error message helper
# ------------------------------------------------------------------


def _timeout_message(method: str, path: str) -> str:
    """Build a clear timeout error message with actionable suggestions."""
    return (
        f"Joplin {method} {path} timed out after {_REQUEST_TIMEOUT}s. "
        "Possible causes:\n"
        "  • The note body is very large and Joplin is slow to process it.\n"
        "  • Joplin is busy (syncing, indexing, or loading a large library).\n"
        "  • Joplin has frozen — try restarting it.\n"
        f"If this happens repeatedly, increase JOPLIN_REQUEST_TIMEOUT in your .env "
        f"(currently {_REQUEST_TIMEOUT}s)."
    )


def _http_error_message(method: str, path: str, e: requests.exceptions.HTTPError) -> str:
    """Build a human-friendly error message from an HTTP error, with auth hint on 401."""
    resp = e.response
    status = resp.status_code if resp is not None else "?"
    if status == 401:
        return (
            f"Joplin rejected the API token (HTTP 401 on {method} {path}). "
            "Check that JOPLIN_API_TOKEN is correct: "
            "Joplin → Tools → Options → Web Clipper → Authorization token."
        )
    if status == 404:
        return f"Joplin resource not found (HTTP 404 on {method} {path}). The note may have been deleted in Joplin."
    body_snippet = ""
    if resp is not None:
        try:
            body_snippet = f" — {resp.text[:120]}"
        except Exception:
            pass
    return f"Joplin {method} {path} failed: HTTP {status}{body_snippet}"


# ------------------------------------------------------------------
# Embedded-media rewriting
# ------------------------------------------------------------------

# Markdown image/link targets pointing at the local media/ sibling directory,
# e.g. ![alt](media/file_x.png) or [name](media/clip.wav).
_MEDIA_LINK_RE = re.compile(r"(!?\[[^\]]*\])\((media/[^)\s]+)\)")


def upload_media_and_rewrite(
    body: str,
    note_dir: Path,
    client: "JoplinClient",
    resource_map: dict[str, str],
) -> tuple[str, dict[str, str]]:
    """Rewrite local ``media/…`` links to Joplin ``:/resourceId`` references.

    Uploads each referenced file as a Joplin resource (once), rewriting both
    image embeds and file links. ``resource_map`` (relative-path → resource_id)
    is the idempotency record from the cache: known paths are reused, new ones
    are added and returned so the caller can persist them. Missing files are
    left as-is so the link still points at the on-disk copy.
    """
    new_map = dict(resource_map)

    def replace(match: re.Match) -> str:
        label, rel_path = match.group(1), match.group(2)
        resource_id = new_map.get(rel_path)
        if resource_id is None:
            file_path = (note_dir / rel_path).resolve()
            if not file_path.is_file():
                logger.warning("[joplin] Media file missing, leaving link: %s", rel_path)
                return match.group(0)
            resource_id = client.create_resource(file_path)
            new_map[rel_path] = resource_id
        return f"{label}(:/{resource_id})"

    return _MEDIA_LINK_RE.sub(replace, body), new_map


# ------------------------------------------------------------------
# Notebook naming helper
# ------------------------------------------------------------------


_PROVIDER_DISPLAY = {
    "chatgpt": "AI-ChatGPT",
    "claude": "AI-Claude",
    # Decision 2026-06-12: Claude Code coding projects nest under the same
    # AI-Claude parent, alongside Claude web projects.
    "claude-code": "AI-Claude",
}


def notebook_path(provider: str, project: str | None) -> tuple[str, str]:
    """Return (parent_notebook, child_notebook) for the given provider and project.

    The parent is the top-level provider notebook; the child is the project name.

    Examples:
        notebook_path("chatgpt", None)             → ("AI-ChatGPT", "No Project")
        notebook_path("chatgpt", "no-project")     → ("AI-ChatGPT", "No Project")
        notebook_path("claude", "budget-tracker")  → ("AI-Claude", "Budget Tracker")
    """
    parent = _PROVIDER_DISPLAY.get(provider, f"AI-{provider.capitalize()}")
    child = (project or "no-project").replace("-", " ").title()
    return parent, child