"""
MCP Server for Evolution Todo - Exposes task operations as AI tools.

Task: T-CHAT-003 to T-CHAT-009
Spec: specs/phase-3-chatbot/spec.md (FR-CHAT-4)
"""
from mcp.server import Server
from mcp.types import Tool, TextContent
from typing import Sequence
from sqlmodel import Session, select
from datetime import datetime
from models import Task
from db import engine

# Initialize MCP Server
mcp_server = Server("evolution-todo-mcp")


@mcp_server.list_tools()
async def list_tools() -> Sequence[Tool]:
    """Return list of available tools for AI agent (11 total)."""
    return [
        # Tool 1: add_task (T-CHAT-004)
        Tool(
            name="add_task",
            description="Create a new task with optional priority, due date, tags, and recurrence",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "title": {"type": "string", "description": "Task title (required)"},
                    "description": {"type": "string", "description": "Task description (optional)"},
                    "priority": {
                        "type": "string",
                        "enum": ["low", "medium", "high", "none"],
                        "default": "none",
                        "description": "Task priority level"
                    },
                    "due_date": {
                        "type": "string",
                        "format": "date-time",
                        "description": "When task is due (ISO 8601 format)"
                    },
                    "tags": {
                        "type": "array",
                        "items": {"type": "string"},
                        "description": "Task tags for categorization"
                    },
                    "recurrence_pattern": {
                        "type": "string",
                        "enum": ["daily", "weekly", "monthly"],
                        "description": "Recurring pattern for repeating tasks"
                    }
                },
                "required": ["user_id", "title"]
            }
        ),

        # Tool 2: list_tasks (T-CHAT-005)
        Tool(
            name="list_tasks",
            description="List all tasks with optional filtering by status, priority, tags, and sorting",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "status": {
                        "type": "string",
                        "enum": ["all", "pending", "completed"],
                        "default": "all",
                        "description": "Filter by completion status"
                    },
                    "priority": {
                        "type": "string",
                        "enum": ["low", "medium", "high", "none"],
                        "description": "Filter by priority level"
                    },
                    "tags": {
                        "type": "string",
                        "description": "Filter by tags (comma-separated)"
                    },
                    "sort_by": {
                        "type": "string",
                        "enum": ["created", "due_date", "priority", "title"],
                        "default": "created",
                        "description": "Sort tasks by field"
                    },
                    "search": {
                        "type": "string",
                        "description": "Search in task titles and descriptions"
                    }
                },
                "required": ["user_id"]
            }
        ),

        # Tool 3: complete_task (T-CHAT-006)
        Tool(
            name="complete_task",
            description="Mark a task as completed or toggle its completion status",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID to complete"}
                },
                "required": ["user_id", "task_id"]
            }
        ),

        # Tool 4: delete_task (T-CHAT-007)
        Tool(
            name="delete_task",
            description="Delete a task permanently",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID to delete"}
                },
                "required": ["user_id", "task_id"]
            }
        ),

        # Tool 5: update_task (T-CHAT-008)
        Tool(
            name="update_task",
            description="Update task details (title, description, priority, due date, tags)",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID to update"},
                    "title": {"type": "string", "description": "New task title"},
                    "description": {"type": "string", "description": "New task description"},
                    "priority": {
                        "type": "string",
                        "enum": ["low", "medium", "high", "none"],
                        "description": "New priority level"
                    },
                    "due_date": {
                        "type": "string",
                        "format": "date-time",
                        "description": "New due date (ISO 8601 format)"
                    },
                    "tags": {
                        "type": "array",
                        "items": {"type": "string"},
                        "description": "New tags list"
                    }
                },
                "required": ["user_id", "task_id"]
            }
        ),

        # Tool 6: search_tasks (T-CHAT-009 - Bonus)
        Tool(
            name="search_tasks",
            description="Search tasks using full-text search across titles and descriptions",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "query": {"type": "string", "description": "Search query"},
                    "priority": {
                        "type": "string",
                        "enum": ["low", "medium", "high", "none"],
                        "description": "Filter results by priority"
                    },
                    "tags": {
                        "type": "string",
                        "description": "Filter results by tags (comma-separated)"
                    }
                },
                "required": ["user_id", "query"]
            }
        ),

        # Tool 7: set_priority (T-CHAT-009 - Bonus)
        Tool(
            name="set_priority",
            description="Change the priority level of a task",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID"},
                    "priority": {
                        "type": "string",
                        "enum": ["low", "medium", "high", "none"],
                        "description": "New priority level"
                    }
                },
                "required": ["user_id", "task_id", "priority"]
            }
        ),

        # Tool 8: add_tags (T-CHAT-009 - Bonus)
        Tool(
            name="add_tags",
            description="Add tags to a task (appends to existing tags)",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID"},
                    "tags": {
                        "type": "array",
                        "items": {"type": "string"},
                        "description": "Tags to add"
                    }
                },
                "required": ["user_id", "task_id", "tags"]
            }
        ),

        # Tool 9: schedule_reminder (T-CHAT-009 - Bonus)
        Tool(
            name="schedule_reminder",
            description="Schedule a reminder notification for a task",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "task_id": {"type": "integer", "description": "Task ID"},
                    "reminder_time": {
                        "type": "string",
                        "format": "date-time",
                        "description": "When to send reminder (ISO 8601 format)"
                    }
                },
                "required": ["user_id", "task_id", "reminder_time"]
            }
        ),

        # Tool 10: get_recurring_tasks (T-CHAT-009 - Bonus)
        Tool(
            name="get_recurring_tasks",
            description="Get all recurring tasks, optionally filtered by pattern",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"},
                    "pattern": {
                        "type": "string",
                        "enum": ["daily", "weekly", "monthly"],
                        "description": "Filter by recurrence pattern"
                    }
                },
                "required": ["user_id"]
            }
        ),

        # Tool 11: analytics_summary (T-CHAT-009 - Bonus)
        Tool(
            name="analytics_summary",
            description="Get task statistics and analytics summary",
            inputSchema={
                "type": "object",
                "properties": {
                    "user_id": {"type": "string", "description": "User ID"}
                },
                "required": ["user_id"]
            }
        )
    ]


@mcp_server.call_tool()
async def call_tool(name: str, arguments: dict) -> Sequence[TextContent]:
    """Execute tool and return result."""
    user_id = arguments.get("user_id")

    try:
        # Tool 1: add_task (T-CHAT-004)
        if name == "add_task":
            with Session(engine) as session:
                task = Task(
                    user_id=user_id,
                    title=arguments["title"],
                    description=arguments.get("description"),
                    priority=arguments.get("priority", "none"),
                    due_date=arguments.get("due_date"),
                    tags=arguments.get("tags", []),
                    recurrence_pattern=arguments.get("recurrence_pattern")
                )
                session.add(task)
                session.commit()
                session.refresh(task)

                message = f"✅ Task created: '{task.title}' (ID: {task.id})"
                if task.due_date:
                    message += f"\n📅 Due: {task.due_date}"
                if task.priority and task.priority != 'none':
                    message += f"\n⚡ Priority: {task.priority}"
                if task.tags:
                    message += f"\n🏷️ Tags: {', '.join(task.tags)}"

                return [TextContent(type="text", text=message)]

        # Tool 2: list_tasks (T-CHAT-005)
        elif name == "list_tasks":
            with Session(engine) as session:
                query = select(Task).where(Task.user_id == user_id)

                # Apply filters
                if arguments.get("status") == "pending":
                    query = query.where(Task.completed == False)
                elif arguments.get("status") == "completed":
                    query = query.where(Task.completed == True)
                if arguments.get("priority"):
                    query = query.where(Task.priority == arguments["priority"])
                if arguments.get("search"):
                    search = f"%{arguments['search']}%"
                    query = query.where(Task.title.like(search))

                # Execute query
                tasks = session.exec(query).all()

                if not tasks:
                    return [TextContent(type="text", text="📋 No tasks found")]

                message = f"📋 Found {len(tasks)} task(s):\n\n"
                for task in tasks:
                    status = "✅" if task.completed else "⬜"
                    message += f"{status} [{task.id}] {task.title}"
                    if task.priority and task.priority != 'none':
                        message += f" ⚡{task.priority}"
                    if task.due_date:
                        message += f" 📅{str(task.due_date)[:10]}"
                    if task.tags:
                        message += f" 🏷️{','.join(task.tags)}"
                    message += "\n"

                return [TextContent(type="text", text=message)]

        # Tool 3: complete_task (T-CHAT-006)
        elif name == "complete_task":
            task_id = arguments["task_id"]
            with Session(engine) as session:
                task = session.get(Task, task_id)
                if not task or task.user_id != user_id:
                    return [TextContent(type="text", text=f"❌ Task {task_id} not found")]

                task.completed = not task.completed
                task.updated_at = datetime.utcnow()
                session.add(task)
                session.commit()

                status = "completed" if task.completed else "uncompleted"
                return [TextContent(
                    type="text",
                    text=f"✅ Task '{task.title}' marked as {status}"
                )]

        # Tool 4: delete_task (T-CHAT-007)
        elif name == "delete_task":
            task_id = arguments["task_id"]
            async with httpx.AsyncClient() as client:
                response = await client.delete(
                    f"{API_BASE}/api/{user_id}/tasks/{task_id}",
                    timeout=10.0
                )
                response.raise_for_status()

                return [TextContent(
                    type="text",
                    text=f"🗑️ Task {task_id} deleted successfully"
                )]

        # Tool 5: update_task (T-CHAT-008)
        elif name == "update_task":
            task_id = arguments["task_id"]
            update_data = {}
            if arguments.get("title"):
                update_data["title"] = arguments["title"]
            if arguments.get("description") is not None:
                update_data["description"] = arguments["description"]
            if arguments.get("priority"):
                update_data["priority"] = arguments["priority"]
            if arguments.get("due_date"):
                update_data["due_date"] = arguments["due_date"]
            if arguments.get("tags"):
                update_data["tags"] = arguments["tags"]

            async with httpx.AsyncClient() as client:
                response = await client.put(
                    f"{API_BASE}/api/{user_id}/tasks/{task_id}",
                    json=update_data,
                    timeout=10.0
                )
                response.raise_for_status()
                result = response.json()

                return [TextContent(
                    type="text",
                    text=f"✏️ Task '{result['title']}' updated successfully"
                )]

        # Tool 6: search_tasks (T-CHAT-009 - Bonus)
        elif name == "search_tasks":
            async with httpx.AsyncClient() as client:
                params = {"q": arguments["query"]}
                if arguments.get("priority"):
                    params["priority"] = arguments["priority"]
                if arguments.get("tags"):
                    params["tags"] = arguments["tags"]

                response = await client.get(
                    f"{API_BASE}/api/{user_id}/tasks/search",
                    params=params,
                    timeout=10.0
                )
                response.raise_for_status()
                tasks = response.json()

                if not tasks:
                    return [TextContent(type="text", text=f"🔍 No tasks found matching '{arguments['query']}'"

)]

                message = f"🔍 Found {len(tasks)} task(s) matching '{arguments['query']}':\n\n"
                for task in tasks:
                    status = "✅" if task['completed'] else "⬜"
                    message += f"{status} [{task['id']}] {task['title']}\n"

                return [TextContent(type="text", text=message)]

        # Tool 7: set_priority (T-CHAT-009 - Bonus)
        elif name == "set_priority":
            task_id = arguments["task_id"]
            priority = arguments["priority"]

            async with httpx.AsyncClient() as client:
                response = await client.put(
                    f"{API_BASE}/api/{user_id}/tasks/{task_id}",
                    json={"priority": priority},
                    timeout=10.0
                )
                response.raise_for_status()
                result = response.json()

                return [TextContent(
                    type="text",
                    text=f"⚡ Task '{result['title']}' priority set to {priority}"
                )]

        # Tool 8: add_tags (T-CHAT-009 - Bonus)
        elif name == "add_tags":
            task_id = arguments["task_id"]
            new_tags = arguments["tags"]

            # First get current task
            async with httpx.AsyncClient() as client:
                get_response = await client.get(
                    f"{API_BASE}/api/{user_id}/tasks/{task_id}",
                    timeout=10.0
                )
                get_response.raise_for_status()
                task = get_response.json()

                # Merge tags
                current_tags = task.get('tags', [])
                merged_tags = list(set(current_tags + new_tags))

                # Update with merged tags
                update_response = await client.put(
                    f"{API_BASE}/api/{user_id}/tasks/{task_id}",
                    json={"tags": merged_tags},
                    timeout=10.0
                )
                update_response.raise_for_status()
                result = update_response.json()

                return [TextContent(
                    type="text",
                    text=f"🏷️ Tags added to '{result['title']}': {', '.join(new_tags)}"
                )]

        # Tool 9: schedule_reminder (T-CHAT-009 - Bonus)
        elif name == "schedule_reminder":
            task_id = arguments["task_id"]
            reminder_time = arguments["reminder_time"]

            async with httpx.AsyncClient() as client:
                response = await client.post(
                    f"{API_BASE}/api/{user_id}/notifications",
                    json={
                        "task_id": task_id,
                        "scheduled_time": reminder_time,
                        "notification_type": "reminder"
                    },
                    timeout=10.0
                )
                response.raise_for_status()
                result = response.json()

                return [TextContent(
                    type="text",
                    text=f"🔔 Reminder scheduled for {reminder_time}"
                )]

        # Tool 10: get_recurring_tasks (T-CHAT-009 - Bonus)
        elif name == "get_recurring_tasks":
            async with httpx.AsyncClient() as client:
                params = {}
                if arguments.get("pattern"):
                    params["pattern"] = arguments["pattern"]

                response = await client.get(
                    f"{API_BASE}/api/{user_id}/tasks/recurrence",
                    params=params,
                    timeout=10.0
                )
                response.raise_for_status()
                tasks = response.json()

                if not tasks:
                    return [TextContent(type="text", text="🔁 No recurring tasks found")]

                message = f"🔁 Found {len(tasks)} recurring task(s):\n\n"
                for task in tasks:
                    pattern = task.get('recurrence_pattern', 'unknown')
                    message += f"🔁 [{task['id']}] {task['title']} - {pattern}\n"

                return [TextContent(type="text", text=message)]

        # Tool 11: analytics_summary (T-CHAT-009 - Bonus)
        elif name == "analytics_summary":
            async with httpx.AsyncClient() as client:
                response = await client.get(
                    f"{API_BASE}/api/{user_id}/stats",
                    timeout=10.0
                )
                response.raise_for_status()
                stats = response.json()

                message = "📊 Task Analytics Summary:\n\n"
                message += f"📋 Total tasks: {stats.get('total_tasks', 0)}\n"
                message += f"✅ Completed: {stats.get('completed_tasks', 0)}\n"
                message += f"⬜ Pending: {stats.get('pending_tasks', 0)}\n"
                message += f"📈 Completion rate: {stats.get('completion_rate', 0)}%\n"

                if stats.get('priority_breakdown'):
                    message += "\n⚡ Priority breakdown:\n"
                    for priority, count in stats['priority_breakdown'].items():
                        message += f"  {priority}: {count}\n"

                if stats.get('overdue_tasks'):
                    message += f"\n⚠️ Overdue tasks: {stats['overdue_tasks']}\n"

                return [TextContent(type="text", text=message)]

        # Unknown tool
        else:
            return [TextContent(
                type="text",
                text=f"❌ Unknown tool: {name}"
            )]

    except httpx.HTTPStatusError as e:
        return [TextContent(
            type="text",
            text=f"❌ API Error ({e.response.status_code}): {e.response.text}"
        )]
    except Exception as e:
        return [TextContent(
            type="text",
            text=f"❌ Error: {str(e)}"
        )]