"""Code regarding samples"""
import os
import sys
import csv
import uuid
from pathlib import Path
from typing import Iterator

import MySQLdb as mdb
from redis import Redis
from MySQLdb.cursors import DictCursor
from flask import (
    flash,
    request,
    url_for,
    redirect,
    Blueprint,
    render_template,
    current_app as app)

from functional_tools import take

from uploader import jobs
from uploader.files import save_file
from uploader.datautils import order_by_family
from uploader.authorisation import require_login
from uploader.input_validation import is_integer_input
from uploader.db_utils import (
    with_db_connection,
    database_connection,
    with_redis_connection)
from uploader.species.models import (all_species,
                                     species_by_id,
                                     order_species_by_family)
from uploader.population.models import(save_population,
                                       population_by_id,
                                       populations_by_species)

from .models import samples_by_species_and_population

samplesbp = Blueprint("samples", __name__)

@samplesbp.route("/samples", methods=["GET"])
def index():
    """Direct entry-point for uploading/handling the samples."""
    with database_connection(app.config["SQL_URI"]) as conn:
        if not bool(request.args.get("species_id")):
            return render_template(
                "samples/index.html",
                species=order_species_by_family(all_species(conn)),
                activelink="samples")
        species = species_by_id(conn, request.args.get("species_id"))
        if not bool(species):
            flash("No such species!", "alert-danger")
            return redirect(url_for("species.populations.samples.index"))
        return redirect(url_for("species.populations.samples.select_population",
                                species_id=species["SpeciesId"]))


@samplesbp.route("<int:species_id>/samples/select-population", methods=["GET"])
def select_population(species_id: int):
    """Select the population to use for the samples."""
    with database_connection(app.config["SQL_URI"]) as conn:
        species = species_by_id(conn, species_id)
        if not bool(species):
            flash("Invalid species!", "alert-danger")
            return redirect(url_for("species.populations.samples.index"))

        if not bool(request.args.get("population_id")):
            return render_template("samples/select-population.html",
                                   species=species,
                                   populations=order_by_family(
                                       populations_by_species(
                                           conn,
                                           species_id),
                                       order_key="FamilyOrder"),
                                   activelink="samples")

        population = population_by_id(conn, request.args.get("population_id"))
        if not bool(population):
            flash("Population not found!", "alert-danger")
            return redirect(url_for(
                "species.populations.samples.select_population",
                species_id=species_id))

        return redirect(url_for("species.populations.samples.list_samples",
                                species_id=species_id,
                                population_id=population["Id"]))

@samplesbp.route("<int:species_id>/populations/<int:population_id>/samples")
def list_samples(species_id: int, population_id: int):
    """
    List the samples in a particular population and give the ability to upload
    new ones.
    """
    with database_connection(app.config["SQL_URI"]) as conn:
        species = species_by_id(conn, species_id)
        if not bool(species):
            flash("Invalid species!", "alert-danger")
            return redirect(url_for("species.populations.samples.index"))

        population = population_by_id(conn, population_id)
        if not bool(population):
            flash("Population not found!", "alert-danger")
            return redirect(url_for(
                "species.populations.samples.select_population",
                species_id=species_id))

        all_samples = samples_by_species_and_population(
            conn, species_id, population_id)
        total_samples = len(all_samples)
        offset = int(request.args.get("from") or 0)
        if offset < 0:
            offset = 0
        count = int(request.args.get("count") or 10)
        return render_template("samples/list-samples.html",
                               species=species,
                               population=population,
                               samples=all_samples[offset:offset+count],
                               offset=offset,
                               count=count,
                               total_samples=total_samples,
                               activelink="list-samples")


def read_samples_file(filepath, separator: str, firstlineheading: bool, **kwargs) -> Iterator[dict]:
    """Read the samples file."""
    with open(filepath, "r", encoding="utf-8") as inputfile:
        reader = csv.DictReader(
            inputfile,
            fieldnames=(
                None if firstlineheading
                else ("Name", "Name2", "Symbol", "Alias")),
            delimiter=separator,
            quotechar=kwargs.get("quotechar", '"'))
        for row in reader:
            yield row


def save_samples_data(conn: mdb.Connection,
                      speciesid: int,
                      file_data: Iterator[dict]):
    """Save the samples to DB."""
    data = ({**row, "SpeciesId": speciesid} for row in file_data)
    total = 0
    with conn.cursor() as cursor:
        while True:
            batch = take(data, 5000)
            if len(batch) == 0:
                break
            cursor.executemany(
                "INSERT INTO Strain(Name, Name2, SpeciesId, Symbol, Alias) "
                "VALUES("
                "    %(Name)s, %(Name2)s, %(SpeciesId)s, %(Symbol)s, %(Alias)s"
                ") ON DUPLICATE KEY UPDATE Name=Name",
                batch)
            total += len(batch)
            print(f"\tSaved {total} samples total so far.")


def cross_reference_samples(conn: mdb.Connection,
                            species_id: int,
                            population_id: int,
                            strain_names: Iterator[str]):
    """Link samples to their population."""
    with conn.cursor(cursorclass=DictCursor) as cursor:
        cursor.execute(
            "SELECT MAX(OrderId) AS loid FROM StrainXRef WHERE InbredSetId=%s",
            (population_id,))
        last_order_id = (cursor.fetchone()["loid"] or 10)
        total = 0
        while True:
            batch = take(strain_names, 5000)
            if len(batch) == 0:
                break
            params_str = ", ".join(["%s"] * len(batch))
            ## This query is slow -- investigate.
            cursor.execute(
                "SELECT s.Id FROM Strain AS s LEFT JOIN StrainXRef AS sx "
                "ON s.Id = sx.StrainId WHERE s.SpeciesId=%s AND s.Name IN "
                f"({params_str}) AND sx.StrainId IS NULL",
                (species_id,) + tuple(batch))
            strain_ids = (sid["Id"] for sid in cursor.fetchall())
            params = tuple({
                "pop_id": population_id,
                "strain_id": strain_id,
                "order_id": last_order_id + (order_id * 10),
                "mapping": "N",
                "pedigree": None
            } for order_id, strain_id in enumerate(strain_ids, start=1))
            cursor.executemany(
                "INSERT INTO StrainXRef( "
                "  InbredSetId, StrainId, OrderId, Used_for_mapping, PedigreeStatus"
                ")"
                "VALUES ("
                "  %(pop_id)s, %(strain_id)s, %(order_id)s, %(mapping)s, "
                "  %(pedigree)s"
                ")",
                params)
            last_order_id += (len(params) * 10)
            total += len(batch)
            print(f"\t{total} total samples cross-referenced to the population "
                  "so far.")


def build_sample_upload_job(# pylint: disable=[too-many-arguments]
        speciesid: int,
        populationid: int,
        samplesfile: Path,
        separator: str,
        firstlineheading: bool,
        quotechar: str):
    """Define the async command to run the actual samples data upload."""
    return [
        sys.executable, "-m", "scripts.insert_samples", app.config["SQL_URI"],
        str(speciesid), str(populationid), str(samplesfile.absolute()),
        separator, f"--redisuri={app.config['REDIS_URL']}",
        f"--quotechar={quotechar}"
    ] + (["--firstlineheading"] if firstlineheading else [])


@samplesbp.route("/upload/species/<int:species_id>/populations/<int:population_id>/samples",
               methods=["GET", "POST"])
@require_login
def upload_samples(species_id: int, population_id: int):#pylint: disable=[too-many-return-statements]
    """Upload the samples."""
    samples_uploads_page = redirect(url_for("samples.upload_samples",
                                            species_id=species_id,
                                            population_id=population_id))
    if not is_integer_input(species_id):
        flash("You did not provide a valid species. Please select one to "
              "continue.",
              "alert-danger")
        return redirect(url_for("expression-data.samples.select_species"))
    species = with_db_connection(lambda conn: species_by_id(conn, species_id))
    if not bool(species):
        flash("Species with given ID was not found.", "alert-danger")
        return redirect(url_for("expression-data.samples.select_species"))

    if not is_integer_input(population_id):
        flash("You did not provide a valid population. Please select one "
              "to continue.",
              "alert-danger")
        return redirect(url_for("samples.select_population",
                                species_id=species_id),
                        code=307)
    population = with_db_connection(
        lambda conn: population_by_id(conn, int(population_id)))
    if not bool(population):
        flash("Invalid grouping/population!", "alert-error")
        return redirect(url_for("samples.select_population",
                                species_id=species_id),
                        code=307)

    if request.method == "GET" or request.files.get("samples_file") is None:
        return render_template("samples/upload-samples.html",
                               species=species,
                               population=population)

    try:
        samples_file = save_file(request.files["samples_file"],
                                 Path(app.config["UPLOAD_FOLDER"]))
    except AssertionError:
        flash("You need to provide a file with the samples data.",
              "alert-error")
        return samples_uploads_page

    firstlineheading = (request.form.get("first_line_heading") == "on")

    separator = request.form.get("separator", ",")
    if separator == "other":
        separator = request.form.get("other_separator", ",")
    if not bool(separator):
        flash("You need to provide a separator character.", "alert-error")
        return samples_uploads_page

    quotechar = (request.form.get("field_delimiter", '"') or '"')

    redisuri = app.config["REDIS_URL"]
    with Redis.from_url(redisuri, decode_responses=True) as rconn:
        the_job = jobs.launch_job(
            jobs.initialise_job(
                rconn,
                jobs.jobsnamespace(),
                str(uuid.uuid4()),
                build_sample_upload_job(
                    species["SpeciesId"],
                    population["InbredSetId"],
                    samples_file,
                    separator,
                    firstlineheading,
                    quotechar),
                "samples_upload",
                app.config["JOBS_TTL_SECONDS"],
                {"job_name": f"Samples Upload: {samples_file.name}"}),
            redisuri,
            f"{app.config['UPLOAD_FOLDER']}/job_errors")
        return redirect(url_for(
            "samples.upload_status", job_id=the_job["jobid"]))

@samplesbp.route("/upload/status/<uuid:job_id>", methods=["GET"])
def upload_status(job_id: uuid.UUID):
    """Check on the status of a samples upload job."""
    job = with_redis_connection(lambda rconn: jobs.job(
        rconn, jobs.jobsnamespace(), job_id))
    if job:
        status = job["status"]
        if status == "success":
            return render_template("samples/upload-success.html", job=job)

        if status == "error":
            return redirect(url_for("samples.upload_failure", job_id=job_id))

        error_filename = Path(jobs.error_filename(
            job_id, f"{app.config['UPLOAD_FOLDER']}/job_errors"))
        if error_filename.exists():
            stat = os.stat(error_filename)
            if stat.st_size > 0:
                return redirect(url_for(
                    "samples.upload_failure", job_id=job_id))

        return render_template(
            "samples/upload-progress.html",
            job=job) # maybe also handle this?

    return render_template("no_such_job.html", job_id=job_id), 400

@samplesbp.route("/upload/failure/<uuid:job_id>", methods=["GET"])
def upload_failure(job_id: uuid.UUID):
    """Display the errors of the samples upload failure."""
    job = with_redis_connection(lambda rconn: jobs.job(
        rconn, jobs.jobsnamespace(), job_id))
    if not bool(job):
        return render_template("no_such_job.html", job_id=job_id), 400

    error_filename = Path(jobs.error_filename(
        job_id, f"{app.config['UPLOAD_FOLDER']}/job_errors"))
    if error_filename.exists():
        stat = os.stat(error_filename)
        if stat.st_size > 0:
            return render_template("worker_failure.html", job_id=job_id)

    return render_template("samples/upload-failure.html", job=job)