from __future__ import annotations

from datetime import date, datetime, time, timedelta, timezone
import json
from typing import Protocol
from uuid import UUID

from fastapi import HTTPException
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from core.config.settings import config
from models.agent_chat_message import AgentChatMessage, AgentChatMessageRole
from models.agent_chat_session import AgentChatSession
from services.base.supabase import supabase_service


class ToolResultPayloadStorage(Protocol):
    async def read_json(
        self, *, bucket: str, path: str
    ) -> dict[str, object] | None: ...


class AgentRepository:
    def __init__(
        self,
        session: AsyncSession,
        *,
        tool_result_storage: ToolResultPayloadStorage | None = None,
    ) -> None:
        self._session = session
        self._tool_result_storage = tool_result_storage

    async def get_session_owner(self, *, session_id: str) -> str:
        try:
            session_uuid = UUID(session_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid session_id") from exc

        stmt = select(AgentChatSession.user_id).where(
            AgentChatSession.id == session_uuid
        )
        owner_id = (await self._session.execute(stmt)).scalar_one_or_none()
        if owner_id is None:
            raise HTTPException(status_code=404, detail="Session not found")
        return str(owner_id)

    async def create_session_for_user(
        self, *, user_id: str, session_id: str | None = None
    ) -> str:
        try:
            user_uuid = UUID(user_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid user_id") from exc
        session_uuid = None
        if session_id is not None:
            try:
                session_uuid = UUID(session_id)
            except ValueError as exc:
                raise HTTPException(
                    status_code=422, detail="Invalid session_id"
                ) from exc

        session = AgentChatSession(
            id=session_uuid,
            user_id=user_uuid,
        )
        self._session.add(session)
        await self._session.flush()
        await self._session.refresh(session)
        return str(session.id)

    async def commit(self) -> None:
        await self._session.commit()

    async def rollback(self) -> None:
        await self._session.rollback()

    async def delete_session(self, *, session_id: str) -> None:
        try:
            session_uuid = UUID(session_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid session_id") from exc
        session = await self._session.get(AgentChatSession, session_uuid)
        if session is not None:
            await self._session.delete(session)
            await self._session.flush()

    async def persist_user_message(
        self,
        *,
        session_id: str,
        run_id: str,
        content_text: str,
        metadata: dict[str, object] | None,
    ) -> None:
        try:
            session_uuid = UUID(session_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid session_id") from exc

        stmt = (
            select(AgentChatSession)
            .where(AgentChatSession.id == session_uuid)
            .with_for_update()
        )
        session_row = (await self._session.execute(stmt)).scalar_one_or_none()
        if session_row is None:
            raise HTTPException(status_code=404, detail="Session not found")

        next_seq = int(session_row.message_count or 0) + 1
        if not _has_title(session_row.title):
            session_title = _derive_session_title(content_text)
            if session_title is not None:
                session_row.title = session_title
        payload_metadata = dict(metadata or {})
        payload_metadata["run_id"] = run_id
        message = AgentChatMessage(
            session_id=session_uuid,
            seq=next_seq,
            role=AgentChatMessageRole.USER,
            content=content_text,
            metadata_json=payload_metadata,
        )
        self._session.add(message)
        session_row.message_count = next_seq
        session_row.last_activity_at = datetime.now(timezone.utc)
        await self._session.flush()

    async def get_history_day(
        self, *, session_id: str, before: date | None
    ) -> dict[str, object] | None:
        try:
            session_uuid = UUID(session_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid session_id") from exc

        timestamp_stmt = (
            select(AgentChatMessage.created_at)
            .where(AgentChatMessage.session_id == session_uuid)
            .where(AgentChatMessage.deleted_at.is_(None))
            .order_by(AgentChatMessage.created_at.desc())
        )
        rows = (await self._session.execute(timestamp_stmt)).scalars().all()
        unique_days: list[date] = []
        for created_at in rows:
            if created_at is None:
                continue
            day = created_at.astimezone(timezone.utc).date()
            if day not in unique_days:
                unique_days.append(day)

        if not unique_days:
            return None

        target_day: date | None = None
        if before is None:
            target_day = unique_days[0]
        else:
            for day in unique_days:
                if day < before:
                    target_day = day
                    break
        if target_day is None:
            return None

        start = datetime.combine(target_day, time.min, tzinfo=timezone.utc)
        end = start + timedelta(days=1)
        message_stmt = (
            select(AgentChatMessage)
            .where(AgentChatMessage.session_id == session_uuid)
            .where(AgentChatMessage.deleted_at.is_(None))
            .where(AgentChatMessage.created_at >= start)
            .where(AgentChatMessage.created_at < end)
            .order_by(AgentChatMessage.seq.asc())
        )
        messages = (await self._session.execute(message_stmt)).scalars().all()
        has_more = any(day < target_day for day in unique_days)
        snapshot_messages: list[dict[str, object]] = []
        for message in messages:
            snapshot_messages.append(await self._to_snapshot_message(message))
        return {
            "day": target_day.isoformat(),
            "hasMore": has_more,
            "messages": snapshot_messages,
        }

    async def get_latest_session_id_for_user(self, *, user_id: str) -> str | None:
        try:
            user_uuid = UUID(user_id)
        except ValueError as exc:
            raise HTTPException(status_code=422, detail="Invalid user_id") from exc
        stmt = (
            select(AgentChatSession.id)
            .where(AgentChatSession.user_id == user_uuid)
            .where(AgentChatSession.deleted_at.is_(None))
            .order_by(AgentChatSession.last_activity_at.desc())
            .limit(1)
        )
        latest_id = (await self._session.execute(stmt)).scalar_one_or_none()
        if latest_id is None:
            return None
        return str(latest_id)

    async def _to_snapshot_message(
        self, message: AgentChatMessage
    ) -> dict[str, object]:
        role = (
            message.role.value
            if isinstance(message.role, AgentChatMessageRole)
            else str(message.role)
        )
        payload: dict[str, object] = {
            "id": str(message.id),
            "role": role,
            "timestamp": message.created_at.astimezone(timezone.utc).isoformat(),
        }

        if role == AgentChatMessageRole.TOOL.value:
            metadata = message.metadata_json or {}
            tool_call_id = metadata.get("tool_call_id")
            if isinstance(tool_call_id, str) and tool_call_id:
                payload["toolCallId"] = tool_call_id

            parsed_content: dict[str, object] | None = None
            try:
                decoded = json.loads(message.content)
                if isinstance(decoded, dict):
                    parsed_content = decoded
            except (TypeError, ValueError):
                parsed_content = None

            hydrated_content: dict[str, object] | None = None
            if self._tool_result_storage is not None:
                storage_bucket = metadata.get("storage_bucket")
                storage_path = metadata.get("storage_path")
                if isinstance(storage_bucket, str) and isinstance(storage_path, str):
                    expected_bucket = config.storage.bucket
                    message_session_id = getattr(message, "session_id", None)
                    expected_prefix = (
                        f"tool-results/{message_session_id}/"
                        if message_session_id is not None
                        else None
                    )
                    tool_call_id = metadata.get("tool_call_id")
                    is_legacy_path = isinstance(
                        tool_call_id, str
                    ) and storage_path.endswith(f"/{tool_call_id}.json")
                    if (
                        storage_bucket == expected_bucket
                        and _is_safe_storage_path(storage_path)
                        and (
                            (
                                expected_prefix is not None
                                and storage_path.startswith(expected_prefix)
                            )
                            or (
                                storage_path.startswith("tool-results/")
                                and is_legacy_path
                            )
                        )
                    ):
                        try:
                            hydrated_content = (
                                await self._tool_result_storage.read_json(
                                    bucket=storage_bucket,
                                    path=storage_path,
                                )
                            )
                        except Exception:
                            hydrated_content = None

            resolved_content = hydrated_content or parsed_content
            payload["content"] = message.content
            if resolved_content is not None:
                ui = resolved_content.get("ui")
                if not isinstance(ui, dict):
                    ui = resolved_content.get("ui_schema")
                if isinstance(ui, dict):
                    payload["ui"] = ui
                display_content = resolved_content.get("content")
                if not isinstance(display_content, str):
                    nested_result = resolved_content.get("result")
                    if isinstance(nested_result, dict):
                        nested_content = nested_result.get("content")
                        if isinstance(nested_content, str):
                            display_content = nested_content
                if (
                    isinstance(display_content, str)
                    and display_content.strip()
                    and (
                        not payload["content"]
                        or _looks_like_offloaded_placeholder(str(payload["content"]))
                    )
                ):
                    payload["content"] = display_content
        else:
            payload["content"] = message.content

            if role == AgentChatMessageRole.USER.value:
                metadata = message.metadata_json or {}
                user_attachments = metadata.get("user_message_attachments")
                if isinstance(user_attachments, dict):
                    bucket = user_attachments.get("bucket")
                    path = user_attachments.get("path")
                    mime_type = user_attachments.get("mime_type")
                    if (
                        isinstance(bucket, str)
                        and isinstance(path, str)
                        and isinstance(mime_type, str)
                    ):
                        try:
                            signed_url = await supabase_service.create_signed_url(
                                bucket=bucket,
                                path=path,
                                expires_in_seconds=3600,
                            )
                            attachment_block = {
                                "type": "binary",
                                "mimeType": mime_type,
                                "url": signed_url,
                            }
                            existing_content = message.content
                            if (
                                isinstance(existing_content, str)
                                and existing_content.strip()
                            ):
                                content_blocks = [
                                    {"type": "text", "text": existing_content}
                                ]
                                content_blocks.append(attachment_block)
                                payload["content"] = content_blocks
                            else:
                                payload["content"] = [attachment_block]
                        except Exception:  # noqa: BLE001
                            pass

        return payload


def _has_title(title: object) -> bool:
    return isinstance(title, str) and bool(title.strip())


def _derive_session_title(content_text: str) -> str | None:
    normalized = " ".join(content_text.split())
    if not normalized:
        return None
    return normalized[:80]


def _is_safe_storage_path(path: str) -> bool:
    normalized = path.strip()
    if not normalized:
        return False
    if normalized.startswith("/"):
        return False
    if ".." in normalized:
        return False
    return True


def _looks_like_offloaded_placeholder(content: str) -> bool:
    normalized = content.strip().lower()
    return normalized in {'{"offloaded":true}', '{"offloaded": true}'}