from datetime import datetime

from sqlalchemy import func, select
from sqlalchemy.orm import Session

from core_domain import (
    AgentRunStatus,
    AgentStatus,
    AgentToolInvocationStatus,
    AgentVersionStatus)
from core_shared import JSONValue

from app.db.models import AgentDefinition, AgentRun, AgentToolInvocation, AgentVersion


class AgentDefinitionRepository:
    def __init__(self, db: Session) -> None:
        self.db = db

    def create(
        self,
        *,
        code: str,
        name: str,
        description: str | None,
        agent_type: str,
        owner_user_id: str | None,
        metadata_json: dict[str, JSONValue] | None) -> AgentDefinition:
        entity = AgentDefinition(
            code=code,
            name=name,
            description=description,
            agent_type=agent_type,
            owner_user_id=owner_user_id,
            metadata_json=metadata_json)
        self.db.add(entity)
        self.db.commit()
        self.db.refresh(entity)
        return entity

    def list_all(self) -> list[AgentDefinition]:
        stmt = (
            select(AgentDefinition)
            .order_by(AgentDefinition.created_time.desc())
        )
        return list(self.db.scalars(stmt))

    def get_by_id(self, *, agent_id: str) -> AgentDefinition | None:
        stmt = (
            select(AgentDefinition)
            .where(AgentDefinition.id == agent_id)
        )
        return self.db.scalar(stmt)

    def update_status(
        self,
        *,
        agent_id: str,
        status: AgentStatus) -> AgentDefinition | None:
        entity = self.get_by_id(agent_id=agent_id)
        if entity is None:
            return None
        entity.status = status
        self.db.commit()
        self.db.refresh(entity)
        return entity


class AgentVersionRepository:
    def __init__(self, db: Session) -> None:
        self.db = db

    def create(
        self,
        *,
        agent_id: str,
        status: AgentVersionStatus,
        role: str,
        goal: str | None,
        system_prompt: str,
        model_config_json: dict[str, JSONValue],
        memory_policy_json: dict[str, JSONValue],
        tool_refs_json: list[dict[str, JSONValue]],
        skill_refs_json: list[dict[str, JSONValue]]) -> AgentVersion:
        version_no = self._next_version_no(agent_id)
        entity = AgentVersion(
            agent_id=agent_id,
            version_no=version_no,
            status=status,
            role=role,
            goal=goal,
            system_prompt=system_prompt,
            model_config_json=model_config_json,
            memory_policy_json=memory_policy_json,
            tool_refs_json=tool_refs_json,
            skill_refs_json=skill_refs_json,
            published_time=datetime.utcnow() if status == "published" else None)
        self.db.add(entity)
        self.db.commit()
        self.db.refresh(entity)
        return entity

    def list_by_agent(self, *, agent_id: str) -> list[AgentVersion]:
        stmt = (
            select(AgentVersion)
            .where(AgentVersion.agent_id == agent_id)
            .order_by(AgentVersion.version_no.desc())
        )
        return list(self.db.scalars(stmt))

    def get_by_id(self, *, agent_version_id: str) -> AgentVersion | None:
        stmt = (
            select(AgentVersion)
            .where(AgentVersion.id == agent_version_id)
        )
        return self.db.scalar(stmt)

    def get_latest_published(self, *, agent_id: str) -> AgentVersion | None:
        stmt = (
            select(AgentVersion)
            .where(AgentVersion.agent_id == agent_id)
            .where(AgentVersion.status == "published")
            .order_by(AgentVersion.version_no.desc())
            .limit(1)
        )
        return self.db.scalar(stmt)

    def _next_version_no(self, agent_id: str) -> int:
        stmt = select(func.max(AgentVersion.version_no)).where(AgentVersion.agent_id == agent_id)
        current_max = self.db.scalar(stmt)
        return (current_max or 0) + 1


class AgentRunRepository:
    def __init__(self, db: Session) -> None:
        self.db = db

    def create(
        self,
        *,
        agent_id: str,
        agent_version_id: str,
        session_id: str | None,
        input_text: str | None,
        input_json: dict[str, JSONValue] | None) -> AgentRun:
        now = datetime.utcnow()
        entity = AgentRun(
            agent_id=agent_id,
            agent_version_id=agent_version_id,
            session_id=session_id,
            input_text=input_text,
            input_json=input_json,
            status="queued",
            queued_time=now)
        self.db.add(entity)
        self.db.commit()
        self.db.refresh(entity)
        return entity

    def list_by_scope(
        self,
        *,
        agent_id: str | None = None,
        session_id: str | None = None) -> list[AgentRun]:
        stmt = select(AgentRun)
        if agent_id is not None:
            stmt = stmt.where(AgentRun.agent_id == agent_id)
        if session_id is not None:
            stmt = stmt.where(AgentRun.session_id == session_id)
        stmt = stmt.order_by(AgentRun.created_time.desc())
        return list(self.db.scalars(stmt))

    def get_by_id(self, *, agent_run_id: str) -> AgentRun | None:
        stmt = (
            select(AgentRun)
            .where(AgentRun.id == agent_run_id)
        )
        return self.db.scalar(stmt)

    def claim_next_queued(
        self,
        *,
        worker_key: str,
        lease_expire_time: datetime) -> AgentRun | None:
        stmt = (
            select(AgentRun)
            .where(AgentRun.status == "queued")
            .order_by(AgentRun.created_time.asc())
            .with_for_update(skip_locked=True)
            .limit(1)
        )
        entity = self.db.scalar(stmt)
        if entity is None:
            return None

        now = datetime.utcnow()
        entity.status = "running"
        entity.worker_key = worker_key
        entity.started_time = entity.started_time or now
        entity.lease_expire_time = lease_expire_time
        self.db.commit()
        self.db.refresh(entity)
        return entity

    def release_expired_leases(self, *, now_time: datetime, max_items: int = 100) -> int:
        stmt = (
            select(AgentRun)
            .where(AgentRun.status == "running")
            .where(AgentRun.lease_expire_time.is_not(None))
            .where(AgentRun.lease_expire_time <= now_time)
            .order_by(AgentRun.lease_expire_time.asc())
            .limit(max_items)
        )
        entities = list(self.db.scalars(stmt))
        for entity in entities:
            entity.status = "queued"
            entity.worker_key = None
            entity.lease_expire_time = None
            entity.queued_time = now_time
            entity.started_time = None
            entity.finished_time = None

        if entities:
            self.db.commit()

        return len(entities)

    def update_status(
        self,
        *,
        agent_run_id: str,
        status: AgentRunStatus,
        worker_key: str | None = None,
        output_text: str | None = None,
        output_json: dict[str, JSONValue] | None = None,
        error_code: str | None = None,
        error_message: str | None = None) -> AgentRun | None:
        entity = self.db.get(AgentRun, agent_run_id)
        if entity is None:
            return None

        now = datetime.utcnow()
        entity.status = status
        entity.worker_key = worker_key
        entity.output_text = output_text
        entity.output_json = output_json
        entity.error_code = error_code
        entity.error_message = error_message
        if status == "running" and entity.started_time is None:
            entity.started_time = now
        if status in {"completed", "failed", "cancelled"}:
            entity.finished_time = now
            entity.lease_expire_time = None

        self.db.commit()
        self.db.refresh(entity)
        return entity


class AgentToolInvocationRepository:
    def __init__(self, db: Session) -> None:
        self.db = db

    def create(
        self,
        *,
        agent_run_id: str,
        agent_id: str,
        agent_version_id: str,
        tool_code: str | None,
        tool_binding_id: str | None,
        status: AgentToolInvocationStatus,
        reason: str | None = None,
        input_json: dict[str, JSONValue] | None = None) -> AgentToolInvocation:
        entity = AgentToolInvocation(
            agent_run_id=agent_run_id,
            agent_id=agent_id,
            agent_version_id=agent_version_id,
            tool_code=tool_code,
            tool_binding_id=tool_binding_id,
            status=status,
            reason=reason,
            input_json=input_json or {})
        self.db.add(entity)
        self.db.commit()
        self.db.refresh(entity)
        return entity

    def list_by_run(
        self,
        *,
        agent_run_id: str) -> list[AgentToolInvocation]:
        stmt = (
            select(AgentToolInvocation)
            .where(AgentToolInvocation.agent_run_id == agent_run_id)
            .order_by(AgentToolInvocation.created_time.asc())
        )
        return list(self.db.scalars(stmt))

    def update_status(
        self,
        *,
        invocation_id: str,
        status: AgentToolInvocationStatus,
        reason: str | None = None,
        output_text: str | None = None,
        output_json: dict[str, JSONValue] | None = None,
        error_message: str | None = None) -> AgentToolInvocation | None:
        entity = self.db.get(AgentToolInvocation, invocation_id)
        if entity is None:
            return None

        now = datetime.utcnow()
        entity.status = status
        entity.reason = reason
        entity.output_text = output_text
        entity.output_json = output_json
        entity.error_message = error_message
        if status == "running" and entity.started_time is None:
            entity.started_time = now
        if status in {"completed", "failed", "skipped"}:
            if entity.started_time is None:
                entity.started_time = now
            entity.finished_time = now
        self.db.commit()
        self.db.refresh(entity)
        return entity