import json
import logging
import os
from datetime import datetime, timezone

import boto3

from shared.dynamo import get_todays_messages, get_unanswered_threads
from shared.gmail import get_authenticated_service, fetch_thread
from shared.secrets import get_config

logger = logging.getLogger(__name__)

_lambda_client = None

TOOLS = [
    {
        "toolSpec": {
            "name": "get_inbox_summary",
            "description": "Get a summary of today's inbox: total emails processed, counts by classification (HIGH, NORMAL, LOW), and a list of the most recent high-priority items.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {
                        "date": {
                            "type": "string",
                            "description": "Date in YYYY-MM-DD format. Defaults to today.",
                        }
                    },
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "get_high_priority_emails",
            "description": "Get all HIGH-priority emails for a given date.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {
                        "date": {
                            "type": "string",
                            "description": "Date in YYYY-MM-DD format. Defaults to today.",
                        }
                    },
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "get_unanswered_threads",
            "description": "Get email threads where Adam hasn't replied in 24+ hours.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {},
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "get_bypassed_work_orders",
            "description": "Get emails sent directly to Adam without CC'ing the work-orders address. These should have gone through the work order system.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {
                        "date": {
                            "type": "string",
                            "description": "Date in YYYY-MM-DD format. Defaults to today.",
                        }
                    },
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "search_emails_by_sender",
            "description": "Search for emails from a specific sender by name or email address. Searches across all classified emails in the database.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {
                        "sender": {
                            "type": "string",
                            "description": "Sender name or email address to search for (case-insensitive partial match).",
                        },
                        "limit": {
                            "type": "integer",
                            "description": "Maximum number of results to return. Defaults to 10.",
                        },
                    },
                    "required": ["sender"],
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "get_email_thread_detail",
            "description": "Get the full message history of a specific email thread from Gmail, including all participants and message snippets.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {
                        "thread_id": {
                            "type": "string",
                            "description": "Gmail thread ID.",
                        }
                    },
                    "required": ["thread_id"],
                }
            },
        }
    },
    {
        "toolSpec": {
            "name": "trigger_daily_digest",
            "description": "Send Adam his daily inbox digest right now, regardless of the scheduled time.",
            "inputSchema": {
                "json": {
                    "type": "object",
                    "properties": {},
                }
            },
        }
    },
]


def _get_lambda_client():
    global _lambda_client
    if _lambda_client is None:
        _lambda_client = boto3.client("lambda")
    return _lambda_client


def _today():
    return datetime.now(timezone.utc).strftime("%Y-%m-%d")


def _format_email(msg):
    return {
        "message_id": msg.get("message_id") or msg.get("pk", "").replace("MSG#", ""),
        "thread_id": msg.get("thread_id", ""),
        "from": msg.get("from_name") or msg.get("from_email", ""),
        "from_email": msg.get("from_email", ""),
        "subject": msg.get("subject", ""),
        "snippet": msg.get("snippet", ""),
        "classification": msg.get("classification", ""),
        "classification_reason": msg.get("classification_reason", ""),
        "internal_date": msg.get("internal_date", 0),
    }


def dispatch_tool(tool_name, tool_input):
    handlers = {
        "get_inbox_summary": _handle_inbox_summary,
        "get_high_priority_emails": _handle_high_priority,
        "get_unanswered_threads": _handle_unanswered,
        "get_bypassed_work_orders": _handle_bypassed,
        "search_emails_by_sender": _handle_search_sender,
        "get_email_thread_detail": _handle_thread_detail,
        "trigger_daily_digest": _handle_trigger_digest,
    }
    handler = handlers.get(tool_name)
    if not handler:
        return {"error": f"Unknown tool: {tool_name}"}
    try:
        return handler(tool_input)
    except Exception:
        logger.exception("Tool %s failed", tool_name)
        return {"error": f"Tool {tool_name} failed"}


def _handle_inbox_summary(inputs):
    date = inputs.get("date") or _today()
    messages = get_todays_messages(date)
    by_class = {}
    for msg in messages:
        c = msg.get("classification", "UNKNOWN")
        by_class[c] = by_class.get(c, 0) + 1

    high = [_format_email(m) for m in messages if m.get("classification") == "HIGH"]
    return {
        "date": date,
        "total": len(messages),
        "by_classification": by_class,
        "high_priority_emails": high[:10],
    }


def _handle_high_priority(inputs):
    date = inputs.get("date") or _today()
    messages = get_todays_messages(date)
    high = [_format_email(m) for m in messages if m.get("classification") == "HIGH"]
    return {"date": date, "count": len(high), "emails": high}


def _handle_unanswered(inputs):
    config = get_config()
    threads = get_unanswered_threads(config["unanswered_threshold_hours"])
    return {
        "count": len(threads),
        "threads": [
            {
                "thread_id": t.get("pk", "").replace("THD#", ""),
                "subject": t.get("subject", ""),
                "last_message_from": t.get("last_message_from", ""),
                "unanswered_since": t.get("unanswered_since", ""),
            }
            for t in threads
        ],
    }


def _handle_bypassed(inputs):
    date = inputs.get("date") or _today()
    messages = get_todays_messages(date)
    bypassed = [_format_email(m) for m in messages if m.get("bypassed_wo")]
    return {"date": date, "count": len(bypassed), "emails": bypassed}


def _handle_search_sender(inputs):
    from shared.dynamo import _get_table

    sender = inputs["sender"].lower()
    limit = inputs.get("limit", 10)

    results = []
    scan_kwargs = {
        "FilterExpression": "sk = :sk AND (contains(from_email, :sender) OR contains(from_name, :sender))",
        "ExpressionAttributeValues": {":sk": "MSG", ":sender": sender},
        "Limit": 500,
    }
    resp = _get_table().scan(**scan_kwargs)
    results.extend(resp.get("Items", []))
    while "LastEvaluatedKey" in resp and len(results) < limit:
        scan_kwargs["ExclusiveStartKey"] = resp["LastEvaluatedKey"]
        resp = _get_table().scan(**scan_kwargs)
        results.extend(resp.get("Items", []))

    results.sort(key=lambda m: int(m.get("internal_date", 0)), reverse=True)
    return {
        "sender_query": inputs["sender"],
        "count": len(results[:limit]),
        "emails": [_format_email(m) for m in results[:limit]],
    }


def _handle_thread_detail(inputs):
    service = get_authenticated_service()
    messages = fetch_thread(service, inputs["thread_id"])
    return {
        "thread_id": inputs["thread_id"],
        "message_count": len(messages),
        "messages": [
            {
                "from": m.get("from_name") or m.get("from_email", ""),
                "from_email": m.get("from_email", ""),
                "subject": m.get("subject", ""),
                "snippet": m.get("snippet", ""),
                "internal_date": m.get("internal_date", 0),
            }
            for m in messages
        ],
    }


def _handle_trigger_digest(inputs):
    _get_lambda_client().invoke(
        FunctionName="exec-aide-daily-digest",
        InvocationType="Event",
    )
    return {"status": "triggered", "message": "Daily digest has been triggered and will arrive shortly."}