"""Public API: history."""

import json

import requests
from wandb_gql import gql
from wandb_gql.client import RetryError

from wandb import util
from wandb.apis.normalize import normalize_exceptions
from wandb.sdk.lib import retry


class HistoryScan:
    QUERY = gql(
        """
        query HistoryPage($entity: String!, $project: String!, $run: String!, $minStep: Int64!, $maxStep: Int64!, $pageSize: Int!) {
            project(name: $project, entityName: $entity) {
                run(name: $run) {
                    history(minStep: $minStep, maxStep: $maxStep, samples: $pageSize)
                }
            }
        }
        """
    )

    def __init__(self, client, run, min_step, max_step, page_size=1000):
        self.client = client
        self.run = run
        self.page_size = page_size
        self.min_step = min_step
        self.max_step = max_step
        self.page_offset = min_step  # minStep for next page
        self.scan_offset = 0  # index within current page of rows
        self.rows = []  # current page of rows

    def __iter__(self):
        self.page_offset = self.min_step
        self.scan_offset = 0
        self.rows = []
        return self

    def __next__(self):
        while True:
            if self.scan_offset < len(self.rows):
                row = self.rows[self.scan_offset]
                self.scan_offset += 1
                return row
            if self.page_offset >= self.max_step:
                raise StopIteration()
            self._load_next()

    next = __next__

    @normalize_exceptions
    @retry.retriable(
        check_retry_fn=util.no_retry_auth,
        retryable_exceptions=(RetryError, requests.RequestException),
    )
    def _load_next(self):
        max_step = self.page_offset + self.page_size
        if max_step > self.max_step:
            max_step = self.max_step
        variables = {
            "entity": self.run.entity,
            "project": self.run.project,
            "run": self.run.id,
            "minStep": int(self.page_offset),
            "maxStep": int(max_step),
            "pageSize": int(self.page_size),
        }

        res = self.client.execute(self.QUERY, variable_values=variables)
        res = res["project"]["run"]["history"]
        self.rows = [json.loads(row) for row in res]
        self.page_offset += self.page_size
        self.scan_offset = 0


class SampledHistoryScan:
    QUERY = gql(
        """
        query SampledHistoryPage($entity: String!, $project: String!, $run: String!, $spec: JSONString!) {
            project(name: $project, entityName: $entity) {
                run(name: $run) {
                    sampledHistory(specs: [$spec])
                }
            }
        }
        """
    )

    def __init__(self, client, run, keys, min_step, max_step, page_size=1000):
        self.client = client
        self.run = run
        self.keys = keys
        self.page_size = page_size
        self.min_step = min_step
        self.max_step = max_step
        self.page_offset = min_step  # minStep for next page
        self.scan_offset = 0  # index within current page of rows
        self.rows = []  # current page of rows

    def __iter__(self):
        self.page_offset = self.min_step
        self.scan_offset = 0
        self.rows = []
        return self

    def __next__(self):
        while True:
            if self.scan_offset < len(self.rows):
                row = self.rows[self.scan_offset]
                self.scan_offset += 1
                return row
            if self.page_offset >= self.max_step:
                raise StopIteration()
            self._load_next()

    next = __next__

    @normalize_exceptions
    @retry.retriable(
        check_retry_fn=util.no_retry_auth,
        retryable_exceptions=(RetryError, requests.RequestException),
    )
    def _load_next(self):
        max_step = self.page_offset + self.page_size
        if max_step > self.max_step:
            max_step = self.max_step
        variables = {
            "entity": self.run.entity,
            "project": self.run.project,
            "run": self.run.id,
            "spec": json.dumps(
                {
                    "keys": self.keys,
                    "minStep": int(self.page_offset),
                    "maxStep": int(max_step),
                    "samples": int(self.page_size),
                }
            ),
        }

        res = self.client.execute(self.QUERY, variable_values=variables)
        res = res["project"]["run"]["sampledHistory"]
        self.rows = res[0]
        self.page_offset += self.page_size
        self.scan_offset = 0