import time
import logging
from piecrust.pipelines.base import (
    PipelineManager, PipelineJobRunContext,
    get_pipeline_name_for_source)
from piecrust.pipelines.records import (
    MultiRecordHistory, MultiRecord, load_records)
from piecrust.workerpool import IWorker


logger = logging.getLogger(__name__)


class BakeWorkerContext(object):
    def __init__(self, appfactory, out_dir, *,
                 force=False, previous_records_path=None,
                 allowed_pipelines=None, forbidden_pipelines=None):
        self.appfactory = appfactory
        self.out_dir = out_dir
        self.force = force
        self.previous_records_path = previous_records_path
        self.allowed_pipelines = allowed_pipelines
        self.forbidden_pipelines = forbidden_pipelines


class BakeWorker(IWorker):
    def __init__(self, ctx):
        self.ctx = ctx
        self.app = None
        self.stats = None
        self.previous_records = None
        self._work_start_time = time.perf_counter()
        self._sources = {}
        self._ppctx = None

    def initialize(self):
        # Create the app local to this worker.
        app = self.ctx.appfactory.create()
        app.config.set('baker/is_baking', True)
        app.config.set('baker/worker_id', self.wid)
        app.config.set('site/asset_url_format', '%page_uri%/%filename%')

        app.env.fs_cache_only_for_main_page = True

        stats = app.env.stats
        stats.registerTimer("BakeWorker_%d_Total" % self.wid)
        stats.registerTimer("BakeWorkerInit")

        self.app = app
        self.stats = stats

        # Load previous record
        if self.ctx.previous_records_path:
            previous_records = load_records(self.ctx.previous_records_path)
        else:
            previous_records = MultiRecord()
        self.previous_records = previous_records

        # Create the pipelines.
        self.ppmngr = PipelineManager(
            app, self.ctx.out_dir,
            worker_id=self.wid, force=self.ctx.force)
        ok_pp = self.ctx.allowed_pipelines
        nok_pp = self.ctx.forbidden_pipelines
        for src in app.sources:
            pname = get_pipeline_name_for_source(src)
            if ok_pp is not None and pname not in ok_pp:
                continue
            if nok_pp is not None and pname in nok_pp:
                continue

            self.ppmngr.createPipeline(src)

            stats.registerTimer("PipelineJobs_%s" % pname,
                                raise_if_registered=False)

        stats.stepTimerSince("BakeWorkerInit", self._work_start_time)

    def process(self, job):
        source_name, item_spec = job['job_spec']
        logger.debug("Received job: %s@%s" % (source_name, item_spec))

        # Check for special jobs.
        if source_name == '__special__':
            if item_spec == 'populate_template_cache':
                for eng in self.app.plugin_loader.getTemplateEngines():
                    eng.populateCache()
            else:
                raise Exception("Unknown special job: %s" % item_spec)
            return {}

        # Run the job!
        job_start = time.perf_counter()
        pp = self.ppmngr.getPipeline(source_name)
        runctx = PipelineJobRunContext(job, pp.record_name,
                                       self.previous_records)
        ppres = {
            'item_spec': item_spec
        }
        pp.run(job, runctx, ppres)

        # Log time spent in this pipeline.
        self.stats.stepTimerSince("PipelineJobs_%s" % pp.PIPELINE_NAME,
                                  job_start)

        return ppres

    def getStats(self):
        stats = self.app.env.stats
        stats.stepTimerSince("BakeWorker_%d_Total" % self.wid,
                             self._work_start_time)
        return stats

    def shutdown(self):
        for src, pp in self._sources.values():
            pp.shutdown(self._ppctx)