"""Durable project calculation queue. Every worker update is generation fenced."""
from uuid import uuid4

from fastapi import HTTPException
from psycopg.types.json import Jsonb


class CalculationJobRepository:
    def __init__(self, connection, project_id):
        self.connection = connection
        self.project_id = str(project_id)

    async def enqueue(self, *, owner_user_id, request_key, tool, parameters, binding, timeout_seconds):
        cursor = await self.connection.execute(
            """INSERT INTO workbench.calculation_jobs
            (job_id,project_id,owner_user_id,request_key,tool,parameters,binding,timeout_seconds)
            VALUES (%s,%s,%s,%s,%s,%s,%s,%s)
            ON CONFLICT(project_id,owner_user_id,request_key) DO NOTHING RETURNING *""",
            (uuid4(), self.project_id, owner_user_id, request_key, tool,
             Jsonb(parameters), Jsonb(binding), timeout_seconds),
        )
        row = await cursor.fetchone()
        if row:
            return dict(row)
        cursor = await self.connection.execute(
            "SELECT * FROM workbench.calculation_jobs WHERE project_id=%s AND owner_user_id=%s AND request_key=%s",
            (self.project_id, owner_user_id, request_key),
        )
        row = dict(await cursor.fetchone())
        if row['tool'] != tool or row['parameters'] != parameters or row['binding'] != binding:
            raise HTTPException(409, 'Calculation request_key was used with different inputs')
        return row

    async def get(self, job_id, owner_user_id=None):
        cursor = await self.connection.execute(
            """SELECT * FROM workbench.calculation_jobs WHERE project_id=%s AND job_id=%s
            AND (%s::uuid IS NULL OR owner_user_id=%s)""",
            (self.project_id, job_id, owner_user_id, owner_user_id),
        )
        row = await cursor.fetchone()
        return dict(row) if row else None

    async def list(self, *, owner_user_id, binding, limit, offset, status=None):
        cursor = await self.connection.execute(
            """SELECT * FROM workbench.calculation_jobs WHERE project_id=%s AND owner_user_id=%s
            AND binding @> %s AND (%s::text IS NULL OR status=%s) ORDER BY created_at DESC,job_id LIMIT %s OFFSET %s""",
            (self.project_id, owner_user_id, Jsonb(binding), status, status, limit, offset),
        )
        return [dict(row) for row in await cursor.fetchall()]

    async def cancel(self, job_id, owner_user_id):
        await self.connection.execute(
            """UPDATE workbench.calculation_jobs SET status=CASE WHEN status='queued' THEN 'cancelled'
            ELSE 'cancel_requested' END,updated_at=clock_timestamp()
            WHERE project_id=%s AND job_id=%s AND owner_user_id=%s AND status IN ('queued','running')""",
            (self.project_id, job_id, owner_user_id),
        )
        return await self.get(job_id, owner_user_id)

    async def recover(self):
        # A crashed write is never automatically replayed.
        await self.connection.execute(
            """UPDATE workbench.calculation_jobs SET status='interrupted',
            error='{"code":"WORKER_INTERRUPTED"}'::jsonb,updated_at=clock_timestamp()
            WHERE project_id=%s AND status IN ('running','cancel_requested')
            AND lease_expires_at < clock_timestamp()""", (self.project_id,),
        )

    async def claim(self, owner, lease_seconds):
        cursor = await self.connection.execute(
            """UPDATE workbench.calculation_jobs j SET status='running',lease_owner=%s,
            lease_generation=j.lease_generation+1,
            lease_expires_at=clock_timestamp()+%s*interval '1 second',updated_at=clock_timestamp()
            WHERE j.job_id=(SELECT job_id FROM workbench.calculation_jobs
              WHERE project_id=%s AND status='queued' ORDER BY created_at,job_id
              FOR UPDATE SKIP LOCKED LIMIT 1) RETURNING j.*""",
            (owner, lease_seconds, self.project_id),
        )
        row = await cursor.fetchone()
        return dict(row) if row else None

    async def heartbeat(self, row, owner, lease_seconds):
        cursor = await self.connection.execute(
            """UPDATE workbench.calculation_jobs SET lease_expires_at=clock_timestamp()+%s*interval '1 second',
            updated_at=clock_timestamp() WHERE project_id=%s AND job_id=%s AND lease_owner=%s
            AND lease_generation=%s AND lease_expires_at>clock_timestamp()
            AND status IN ('running','cancel_requested') RETURNING status""",
            (lease_seconds, self.project_id, row['job_id'], owner, row['lease_generation']),
        )
        result = await cursor.fetchone()
        return result['status'] if result else None

    async def finish(self, row, owner, status, *, result=None, error=None):
        cursor = await self.connection.execute(
            """UPDATE workbench.calculation_jobs SET status=%s,result=%s,error=%s,updated_at=clock_timestamp()
            WHERE project_id=%s AND job_id=%s AND lease_owner=%s AND lease_generation=%s
            AND lease_expires_at>clock_timestamp() AND status IN ('running','cancel_requested')
            AND (status!='cancel_requested' OR %s IN ('cancelled','interrupted')
                 OR (%s='failed' AND %s='CLEANUP_FAILED')) RETURNING job_id""",
            (status, Jsonb(result) if result is not None else None, Jsonb(error) if error else None,
             self.project_id, row['job_id'], owner, row['lease_generation'], status, status, (error or {}).get('code')),
        )
        return await cursor.fetchone() is not None