"""Task agent — full CRUD for tasks and task comments."""

from __future__ import annotations

from datetime import datetime, timezone
import re
from typing import Any

from langchain_core.tools import tool

from app.core.ws_context import execute_on_client

_UUID_RE = re.compile(
    r"^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$"
)


def _is_uuid(value: str) -> bool:
    return bool(_UUID_RE.match(value))

TASK_SYSTEM_PROMPT = (
    "You are a task management assistant for a project workspace.\n"
    "You create, update, list, and track tasks and their comments.\n\n"
    "Rules:\n"
    "  - status must be one of: todo, in_progress, done\n"
    "  - priority must be one of: high, medium, low\n"
    "  - due_date is a Unix timestamp in milliseconds; convert human dates\n"
    "  - assignees is a JSON-encoded array of strings (e.g. '[\"Alice\",\"Bob\"]')\n"
    "  - project_id is optional; link to a project when the user mentions one\n"
    "  - is_ai_suggested: 1 only when proactively proposing a task the user\n"
    "    did not explicitly request; 0 otherwise\n"
    "  - is_ai_suggested: 1 only when proactively proposing a task the user did not explicitly request; 0 otherwise\n"
    "  - Use list_tasks_due_today for 'what's due today' queries\n"
    "  - For update_task, use -1 for integer fields you do not want to change\n"
    "  - Always confirm the action in plain, user-friendly language."
)


# ── Task tools ────────────────────────────────────────────────────────


@tool
async def list_tasks(
    project_id: str = "",
    status: str = "",
    search: str = "",
    order_by: str = "",
) -> str:
    """List tasks, optionally filtered by project_id, status (todo|in_progress|done),
    a search string, or an order_by field name (dueDate|priority|createdAt)."""
    normalized_project_id = project_id if (project_id and _is_uuid(project_id)) else ""
    result = await execute_on_client(
        action="select",
        table="tasks",
        filters={
            "projectId": normalized_project_id or None,
            "status": status or None,
            "search": search or None,
            "orderBy": order_by or None,
        },
    )
    rows = result.get("rows", [])
    if not rows:
        return "No tasks found matching the given filters."
    lines = [
        f"- {r['title']} (status: {r['status']}, priority: {r['priority']}, id: {r['id']})"
        for r in rows
    ]
    return f"Found {len(rows)} task(s):\n" + "\n".join(lines)


@tool
async def create_task(
    title: str,
    description: str = "",
    status: str = "todo",
    priority: str = "medium",
    assignees: str = "[]",
    due_date: int = 0,
    project_id: str = "",
    is_ai_suggested: int = 0,
) -> str:
    """Create a new task.
    title: task title (required)
    description: optional details
    status: todo | in_progress | done  (default: todo)
    priority: high | medium | low  (default: medium)
    assignees: JSON-encoded array of assignee names, e.g. '["Alice"]'
    due_date: Unix timestamp in milliseconds; 0 means no due date
    project_id: optional UUID of the parent project
    is_ai_suggested: 1 if proactively suggested, 0 if user-requested
    """
    result = await execute_on_client(
        action="insert",
        table="tasks",
        data={
            "title": title,
            "description": description or None,
            "status": status,
            "priority": priority,
            "assignee": assignees,
            "dueDate": due_date or None,
            "projectId": project_id or None,
            "isAiSuggested": is_ai_suggested,
        },
    )
    row = result["row"]
    return (
        f"Task created: '{row['title']}' "
        f"(id: {row['id']}, status: {row['status']}, priority: {row['priority']})"
    )


@tool
async def update_task(
    task_id: str,
    title: str = "",
    description: str = "",
    status: str = "",
    priority: str = "",
    assignees: str = "",
    due_date: int = -1,
    project_id: str = "",
) -> str:
    """Update fields on an existing task. Only pass fields you want to change.
    task_id: the task's UUID (required)
    due_date: -1 means unchanged; 0 clears the due date; any positive value sets it
    """
    updates: dict[str, Any] = {}
    if title:
        updates["title"] = title
    if description:
        updates["description"] = description
    if status:
        updates["status"] = status
    if priority:
        updates["priority"] = priority
    if assignees:
        updates["assignee"] = assignees
    if due_date != -1:
        updates["dueDate"] = due_date or None
    if project_id:
        updates["projectId"] = project_id
    result = await execute_on_client(
        action="update",
        table="tasks",
        data={"id": task_id, "updates": updates},
    )
    row = result["row"]
    return f"Task updated: '{row['title']}' (id: {row['id']}, status: {row['status']})"


@tool
async def delete_task(task_id: str) -> str:
    """Delete a task permanently by its UUID."""
    await execute_on_client(action="delete", table="tasks", data={"id": task_id})
    return f"Task {task_id} deleted."


@tool
async def list_tasks_due_today() -> str:
    """List all tasks whose due date falls on today's date."""
    now = datetime.now(tz=timezone.utc)
    start_ms = int(datetime(now.year, now.month, now.day, tzinfo=timezone.utc).timestamp() * 1000)
    end_ms = start_ms + 86_400_000 - 1  # last ms of today
    result = await execute_on_client(
        action="select",
        table="tasks",
        filters={"dueDateFrom": start_ms, "dueDateTo": end_ms},
    )
    rows = result.get("rows", [])
    if not rows:
        return "No tasks are due today."
    lines = [
        f"- {r['title']} (priority: {r['priority']}, status: {r['status']}, id: {r['id']})"
        for r in rows
    ]
    return f"Tasks due today ({len(rows)}):\n" + "\n".join(lines)


# ── Task comment tools ────────────────────────────────────────────────


@tool
async def list_task_comments(task_id: str) -> str:
    """List all comments on a task by its UUID."""
    result = await execute_on_client(
        action="select",
        table="taskComments",
        filters={"taskId": task_id},
    )
    rows = result.get("rows", [])
    if not rows:
        return f"No comments found for task {task_id}."
    lines = [f"- [{r['author']}]: {r['content']} (id: {r['id']})" for r in rows]
    return f"Found {len(rows)} comment(s):\n" + "\n".join(lines)


@tool
async def add_task_comment(task_id: str, author: str, content: str) -> str:
    """Add a comment to a task.
    task_id: UUID of the task to comment on
    author: name or ID of the comment author
    content: comment text
    """
    result = await execute_on_client(
        action="insert",
        table="taskComments",
        data={"taskId": task_id, "author": author, "content": content},
    )
    row = result.get("row", {})
    row_author = row.get("author", author)
    # Electron payloads can vary (taskId vs task_id). Fall back to input task_id.
    row_task_id = row.get("taskId") or row.get("task_id") or task_id
    row_comment_id = row.get("id", "unknown")
    return f"Comment added by {row_author} on task {row_task_id} (comment id: {row_comment_id})."


@tool
async def delete_task_comment(comment_id: str) -> str:
    """Delete a task comment by its UUID."""
    await execute_on_client(action="delete", table="taskComments", data={"id": comment_id})
    return f"Comment {comment_id} deleted."


# ── Agent ─────────────────────────────────────────────────────────────


TASK_TOOLS: list[Any] = [
    list_tasks,
    create_task,
    update_task,
    delete_task,
    list_tasks_due_today,
    list_task_comments,
    add_task_comment,
    delete_task_comment,
]