"""ClickUp REST API client for the runner.

Adapted from cheddahbot/clickup.py -- stripped to what the runner needs,
with additions for checkbox, stage dropdown, and attachment operations.
"""

from __future__ import annotations

import logging
import time
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any

import httpx

log = logging.getLogger(__name__)

BASE_URL = "https://api.clickup.com/api/v2"


@dataclass
class ClickUpTask:
    """Lightweight representation of a ClickUp task."""

    id: str
    name: str
    status: str
    description: str = ""
    task_type: str = ""  # Work Category value
    url: str = ""
    due_date: str = ""  # Unix-ms timestamp string, or ""
    custom_fields: dict[str, Any] = field(default_factory=dict)
    custom_fields_raw: list[dict] = field(default_factory=list)
    list_id: str = ""
    list_name: str = ""
    folder_name: str = ""
    tags: list[str] = field(default_factory=list)
    attachments: list[dict] = field(default_factory=list)

    @classmethod
    def from_api(
        cls, data: dict, task_type_field_name: str = "Work Category"
    ) -> ClickUpTask:
        """Parse a task from the ClickUp API response."""
        custom_fields: dict[str, Any] = {}
        custom_fields_raw = data.get("custom_fields", [])
        task_type = ""

        for cf in custom_fields_raw:
            cf_name = cf.get("name", "")
            cf_value = cf.get("value")

            # Resolve dropdown type_config to label
            if cf.get("type") == "drop_down" and cf_value is not None:
                options = cf.get("type_config", {}).get("options", [])
                order_index = cf_value if isinstance(cf_value, int) else None
                for opt in options:
                    if (
                        order_index is not None
                        and opt.get("orderindex") == order_index
                    ) or opt.get("id") == cf_value:
                        cf_value = opt.get("name", cf_value)
                        break

            custom_fields[cf_name] = cf_value
            if cf_name == task_type_field_name:
                task_type = str(cf_value) if cf_value else ""

        status_name = data.get("status", {}).get("status", "unknown")
        raw_due = data.get("due_date")
        due_date = str(raw_due) if raw_due else ""
        tags = [tag["name"] for tag in data.get("tags", [])]

        # Folder name from list -> folder if available
        folder_data = data.get("folder", {})
        folder_name = folder_data.get("name", "") if folder_data else ""

        return cls(
            id=data["id"],
            name=data.get("name", ""),
            status=status_name.lower(),
            description=data.get("description", "") or "",
            task_type=task_type,
            url=data.get("url", ""),
            due_date=due_date,
            custom_fields=custom_fields,
            custom_fields_raw=custom_fields_raw,
            list_id=data.get("list", {}).get("id", ""),
            list_name=data.get("list", {}).get("name", ""),
            folder_name=folder_name,
            tags=tags,
        )

    def get_field_value(self, field_name: str) -> Any:
        """Get a custom field value by name."""
        return self.custom_fields.get(field_name)

    def has_xlsx_attachment(self) -> bool:
        """Check if this task has an .xlsx attachment."""
        return any(
            a.get("title", "").lower().endswith(".xlsx")
            or a.get("url", "").lower().endswith(".xlsx")
            for a in self.attachments
        )


class ClickUpClient:
    """ClickUp REST API v2 client for the runner."""

    def __init__(self, api_token: str, task_type_field_name: str = "Work Category"):
        self._token = api_token
        self._task_type_field_name = task_type_field_name
        self._client = httpx.Client(
            base_url=BASE_URL,
            headers={
                "Authorization": api_token,
                "Content-Type": "application/json",
            },
            timeout=30.0,
        )
        # Cache: field_name -> {field_id, options} per list_id
        self._field_cache: dict[str, dict[str, Any]] = {}

    def close(self):
        self._client.close()

    # ── Retry helper ──

    @staticmethod
    def _retry(fn, max_attempts: int = 3, backoff: float = 2.0):
        """Retry on 5xx / transport errors with exponential backoff."""
        last_exc: Exception | None = None
        for attempt in range(1, max_attempts + 1):
            try:
                return fn()
            except (httpx.TransportError, httpx.HTTPStatusError) as e:
                if (
                    isinstance(e, httpx.HTTPStatusError)
                    and e.response.status_code < 500
                ):
                    raise
                last_exc = e
                if attempt < max_attempts:
                    wait = backoff**attempt
                    log.warning(
                        "Retry %d/%d after %.1fs: %s",
                        attempt,
                        max_attempts,
                        wait,
                        e,
                    )
                    time.sleep(wait)
        raise last_exc  # type: ignore[misc]

    # ── Read ──

    def get_tasks(
        self,
        list_id: str,
        statuses: list[str] | None = None,
        due_date_lt: int | None = None,
        due_date_gt: int | None = None,
        include_closed: bool = False,
    ) -> list[ClickUpTask]:
        """Fetch tasks from a list with optional filters."""
        params: dict[str, Any] = {
            "include_closed": "true" if include_closed else "false",
            "subtasks": "true",
        }
        if statuses:
            for s in statuses:
                params.setdefault("statuses[]", [])
                if isinstance(params["statuses[]"], list):
                    params["statuses[]"].append(s)
        if due_date_lt is not None:
            params["due_date_lt"] = str(due_date_lt)
        if due_date_gt is not None:
            params["due_date_gt"] = str(due_date_gt)

        # httpx needs repeated params as list of tuples
        param_list = []
        for k, v in params.items():
            if isinstance(v, list):
                for item in v:
                    param_list.append((k, item))
            else:
                param_list.append((k, v))

        resp = self._client.get(f"/list/{list_id}/task", params=param_list)
        resp.raise_for_status()
        tasks_data = resp.json().get("tasks", [])
        return [
            ClickUpTask.from_api(t, self._task_type_field_name) for t in tasks_data
        ]

    def get_task(self, task_id: str) -> ClickUpTask:
        """Fetch a single task by ID."""
        resp = self._client.get(f"/task/{task_id}")
        resp.raise_for_status()
        return ClickUpTask.from_api(resp.json(), self._task_type_field_name)

    def get_folders(self, space_id: str) -> list[dict]:
        """Return folders in a space with their lists."""
        resp = self._client.get(f"/space/{space_id}/folder")
        resp.raise_for_status()
        folders = []
        for f in resp.json().get("folders", []):
            lists = [
                {"id": lst["id"], "name": lst["name"]} for lst in f.get("lists", [])
            ]
            folders.append({"id": f["id"], "name": f["name"], "lists": lists})
        return folders

    def get_tasks_from_overall_lists(
        self,
        space_id: str,
        due_date_lt: int | None = None,
    ) -> list[ClickUpTask]:
        """Fetch tasks from all 'Overall' lists in each folder.

        Does NOT filter by status -- we need all tasks so we can check
        the Delegate to Claude checkbox ourselves.
        """
        all_tasks: list[ClickUpTask] = []
        overall_ids: list[str] = []

        try:
            folders = self.get_folders(space_id)
            for folder in folders:
                for lst in folder["lists"]:
                    if lst["name"].lower() == "overall":
                        overall_ids.append(lst["id"])
        except httpx.HTTPStatusError as e:
            log.warning("Failed to fetch folders for space %s: %s", space_id, e)
            return []

        for list_id in overall_ids:
            try:
                tasks = self.get_tasks(
                    list_id, due_date_lt=due_date_lt
                )
                all_tasks.extend(tasks)
            except httpx.HTTPStatusError as e:
                log.warning("Failed to fetch tasks from list %s: %s", list_id, e)

        log.info(
            "Found %d tasks across %d Overall lists",
            len(all_tasks),
            len(overall_ids),
        )
        return all_tasks

    def get_task_attachments(self, task_id: str) -> list[dict]:
        """Get attachments for a task.

        Returns list of dicts with keys: id, title, url, date, etc.
        NOTE: Requires ClickUp Business plan or higher.
        """
        try:
            resp = self._client.get(f"/task/{task_id}/attachment")
            resp.raise_for_status()
            return resp.json().get("attachments", [])
        except httpx.HTTPStatusError as e:
            if e.response.status_code == 401:
                log.warning(
                    "Attachment listing not available (may require Business plan)"
                )
            else:
                log.warning(
                    "Failed to get attachments for task %s: %s", task_id, e
                )
            return []

    def download_attachment(self, url: str, dest: Path) -> bool:
        """Download a ClickUp attachment to a local file.

        ClickUp attachment URLs are pre-signed S3 URLs that don't need
        auth headers, so we use a plain httpx request (not the API client).

        Returns True on success, False on failure.
        """
        try:
            with httpx.stream("GET", url, follow_redirects=True, timeout=60.0) as resp:
                resp.raise_for_status()
                with open(dest, "wb") as f:
                    for chunk in resp.iter_bytes(chunk_size=8192):
                        f.write(chunk)
            log.info("Downloaded attachment to %s", dest)
            return True
        except Exception as e:
            log.warning("Failed to download attachment from %s: %s", url, e)
            return False

    def get_custom_fields(self, list_id: str) -> list[dict]:
        """Get custom field definitions for a list."""
        try:
            resp = self._client.get(f"/list/{list_id}/field")
            resp.raise_for_status()
            return resp.json().get("fields", [])
        except httpx.HTTPStatusError as e:
            log.error("Failed to get custom fields for list %s: %s", list_id, e)
            return []

    # ── Write ──

    def update_task_status(self, task_id: str, status: str) -> bool:
        """Update a task's status."""
        try:

            def _call():
                resp = self._client.put(
                    f"/task/{task_id}", json={"status": status}
                )
                resp.raise_for_status()
                return resp

            self._retry(_call)
            log.info("Updated task %s status to '%s'", task_id, status)
            return True
        except (httpx.TransportError, httpx.HTTPStatusError) as e:
            log.error("Failed to update task %s status: %s", task_id, e)
            return False

    def add_comment(self, task_id: str, text: str) -> bool:
        """Add a comment to a task."""
        try:

            def _call():
                resp = self._client.post(
                    f"/task/{task_id}/comment",
                    json={"comment_text": text},
                )
                resp.raise_for_status()
                return resp

            self._retry(_call)
            log.info("Added comment to task %s", task_id)
            return True
        except (httpx.TransportError, httpx.HTTPStatusError) as e:
            log.error("Failed to add comment to task %s: %s", task_id, e)
            return False

    def upload_attachment(self, task_id: str, file_path: str | Path) -> bool:
        """Upload a file attachment to a task.

        Uses module-level httpx.post() because the shared client sets
        Content-Type: application/json which conflicts with multipart.
        """
        fp = Path(file_path)
        if not fp.exists():
            log.warning("Attachment file not found: %s", fp)
            return False
        try:

            def _call():
                with open(fp, "rb") as f:
                    resp = httpx.post(
                        f"{BASE_URL}/task/{task_id}/attachment",
                        headers={"Authorization": self._token},
                        files={
                            "attachment": (
                                fp.name,
                                f,
                                "application/octet-stream",
                            )
                        },
                        timeout=60.0,
                    )
                resp.raise_for_status()
                return resp

            self._retry(_call)
            log.info("Uploaded attachment %s to task %s", fp.name, task_id)
            return True
        except (httpx.TransportError, httpx.HTTPStatusError) as e:
            log.warning("Failed to upload attachment to task %s: %s", task_id, e)
            return False

    def set_custom_field_value(
        self, task_id: str, field_id: str, value: Any
    ) -> bool:
        """Set a custom field value by field ID."""
        try:

            def _call():
                resp = self._client.post(
                    f"/task/{task_id}/field/{field_id}",
                    json={"value": value},
                )
                resp.raise_for_status()
                return resp

            self._retry(_call)
            log.info("Set field %s on task %s", field_id, task_id)
            return True
        except (httpx.TransportError, httpx.HTTPStatusError) as e:
            log.error(
                "Failed to set field %s on task %s: %s", field_id, task_id, e
            )
            return False

    def _resolve_field(
        self, list_id: str, field_name: str
    ) -> dict[str, Any] | None:
        """Look up a custom field's ID and options by name.

        Returns {"field_id": "...", "type": "...", "options": {...}} or None.
        Caches per list_id:field_name.
        """
        cache_key = f"{list_id}:{field_name}"
        if cache_key in self._field_cache:
            return self._field_cache[cache_key]

        fields = self.get_custom_fields(list_id)
        for f in fields:
            if f.get("name") == field_name:
                options: dict[str, str] = {}
                if f.get("type") == "drop_down":
                    for opt in f.get("type_config", {}).get("options", []):
                        opt_name = opt.get("name", "")
                        opt_id = opt.get("id", "")
                        if opt_name and opt_id:
                            options[opt_name] = opt_id
                result = {
                    "field_id": f["id"],
                    "type": f.get("type", ""),
                    "options": options,
                }
                self._field_cache[cache_key] = result
                return result

        log.warning("Field '%s' not found in list %s", field_name, list_id)
        return None

    def set_field_by_name(
        self, task_id: str, list_id: str, field_name: str, value: Any
    ) -> bool:
        """Set a custom field by name, auto-resolving dropdown UUIDs.

        For dropdowns, value is matched against option names (case-insensitive).
        For checkboxes, value should be True/False (sent as "true"/"false").
        """
        info = self._resolve_field(list_id, field_name)
        if not info:
            return False

        resolved = value

        if info["type"] == "drop_down" and isinstance(value, str):
            for opt_name, opt_id in info["options"].items():
                if opt_name.lower() == value.lower():
                    resolved = opt_id
                    break
            else:
                log.warning(
                    "Dropdown option '%s' not found for field '%s'",
                    value,
                    field_name,
                )
                return False

        return self.set_custom_field_value(task_id, info["field_id"], resolved)

    # ── Convenience: checkbox operations ──

    def set_checkbox(
        self, task_id: str, list_id: str, field_name: str, checked: bool
    ) -> bool:
        """Set a checkbox custom field to checked (True) or unchecked (False)."""
        info = self._resolve_field(list_id, field_name)
        if not info:
            return False
        # ClickUp checkbox API expects "true" or "false" string
        return self.set_custom_field_value(
            task_id, info["field_id"], "true" if checked else "false"
        )

    def is_checkbox_checked(self, task: ClickUpTask, field_name: str) -> bool:
        """Check if a checkbox field is checked on a task.

        ClickUp checkbox values come back as True/False or "true"/"false".
        """
        val = task.custom_fields.get(field_name)
        if val is None:
            return False
        if isinstance(val, bool):
            return val
        if isinstance(val, str):
            return val.lower() == "true"
        return bool(val)

    # ── Convenience: stage operations ──

    def get_stage(self, task: ClickUpTask, field_name: str = "Stage") -> str:
        """Get the current stage value from a task."""
        val = task.custom_fields.get(field_name)
        return str(val).lower().strip() if val else ""

    def set_stage(
        self,
        task_id: str,
        list_id: str,
        stage_value: str,
        field_name: str = "Stage",
    ) -> bool:
        """Set the Stage dropdown on a task."""
        return self.set_field_by_name(task_id, list_id, field_name, stage_value)