"""Our mod_wsgi frontend to autoplot generation"""

import json
import os
import sys
import syslog
import tempfile
import traceback
from datetime import timezone
from io import BytesIO
from zoneinfo import ZoneInfo

import matplotlib as mpl
import numpy as np
import pandas as pd
import rasterio
from pandas.api.types import is_datetime64_any_dtype as isdt
from PIL import Image
from pyiem.exceptions import (
    BadWebRequest,
    IncompleteWebRequest,
    NoDataFound,
    UnknownStationException,
)
from pyiem.reference import ISO8601
from pyiem.util import get_autoplot_context, utc
from pyiem.webutil import TELEMETRY, iemapp, write_telemetry
from pymemcache.client import Client
from six import string_types

from iemweb import error_log
from iemweb.autoplot import import_script

# Attempt to stop hangs within mod_wsgi and numpy
np.seterr(all="ignore")


HTTP200 = "200 OK"
HTTP400 = "400 Bad Request"
HTTP422 = "422 Unprocessable Entity"
HTTP500 = "500 Internal Server Error"


def format_geojson_response(gdf: pd.DataFrame, defaultcol: str) -> str:
    """Convert geodataframe into GeoJson."""
    # Avert your eyes children
    jdict = json.loads(gdf.to_json(), parse_float=lambda x: round(float(x), 2))
    jdict["meta"] = {}
    jdict["meta"]["propdefault"] = defaultcol
    jdict["meta"]["proporder"] = [x for x in gdf.columns if x != "geom"]
    return json.dumps(jdict)


def parser(cgistr: str) -> dict:
    """Convert a CGI string into a dict that gets passed to the plotting
    routine"""
    # want predictable / stable URIs, generally.
    data = {}
    # GIGO
    if cgistr.find("::::") > -1:
        raise IncompleteWebRequest("Too many semicolons")
    for token in cgistr.replace(":::", ": ::").split("::"):
        token2 = token.split(":")
        if len(token2) != 2:
            continue
        if token2[1] == " ":  # Undo hack above
            token2[1] = ""
        if token2[0] in data:
            if isinstance(data[token2[0]], string_types):
                data[token2[0]] = [data[token2[0]]]
            data[token2[0]].append(token2[1])
        else:
            data[token2[0]] = token2[1]
    return data


def get_response_headers(status, fmt):
    """Figure out some headers"""
    extra = None
    if fmt == "png":
        ctype = "image/png"
    elif fmt == "js":
        ctype = "application/javascript"
    elif fmt == "geojson":
        ctype = "application/vnd.geo+json"
    elif fmt == "svg":
        ctype = "image/svg+xml"
    elif fmt == "pdf":
        ctype = "application/pdf"
    elif fmt in ["csv", "txt"]:
        ctype = "text/plain"
    elif fmt == "geotiff":
        # Can't handle writting error into this type
        if status != HTTP200:
            ctype = "text/plain"
        else:
            ctype = "image/tiff"
            extra = [
                ("Content-Disposition", "attachment;Filename=autoplot.geotiff")
            ]
    else:
        if status != HTTP200:
            ctype = "text/plain"
        else:
            ctype = "application/vnd.ms-excel"
            extra = [("Content-Disposition", "attachment;Filename=iem.xlsx")]
    res = [("Content-type", ctype)]
    if extra:
        res.extend(extra)
    return res


def error_image(message, fmt):
    """Create an error image"""
    fig = mpl.figure.Figure(figsize=(8, 6))
    ax = fig.add_subplot(1, 1, 1)
    cleantext = str(message).replace("\t", "")
    msg = f"IEM Autoplot generation resulted in an error\n{cleantext}"
    ax.text(0.5, 0.5, msg, transform=ax.transAxes, ha="center", va="center")
    ax.axis("off")
    ram = BytesIO()
    fig.savefig(ram, format=fmt, dpi=100)
    ram.seek(0)
    fig.clear()
    return ram.read()


def handle_error(exp, fmt, environ: dict):
    """Handle errors"""
    exc_type, exc_value, exc_traceback = sys.exc_info()
    tb = traceback.extract_tb(exc_traceback)[-1]
    if not isinstance(exp, UnknownStationException):
        error_log(
            environ,
            f"URI:{environ['REQUEST_URI']} {exp.__class__.__name__} "
            f"method:{tb[2]} lineno:{tb[1]} {exp}",
        )
    if not isinstance(
        exp,
        IncompleteWebRequest | NoDataFound | UnknownStationException,
    ):
        traceback.print_exc()
    del (exc_type, exc_value, exc_traceback, tb)
    if fmt in ["png", "svg", "pdf"]:
        return error_image(str(exp), fmt)
    if fmt == "js":
        return f"alert('{exp}');"
    return str(exp)


def get_res_by_fmt(p, fmt, fdict):
    """Do the work of actually calling things"""
    mod = import_script(p)

    meta = mod.get_description()
    # When _gallery is set, inspect meta to see if it has something hardcoded
    if fdict.get("_gallery") is not None and meta.get("gallery") is not None:
        fdict.update(meta["gallery"])
    # Allow returning of javascript as a string
    ctx = get_autoplot_context(fdict, mod.get_description())
    if fmt == "js":
        # Need to pass the container name
        ctx["_e"] = fdict.get("_e", "ap_container")
        res = mod.get_highcharts(ctx)
    elif fmt == "geotiff":
        (img, imgaff, crs) = mod.get_raster(ctx)
        ram = BytesIO()
        with rasterio.open(
            ram,
            "w",
            driver="GTiff",
            width=img.shape[1],
            height=img.shape[0],
            count=1,
            dtype=img.dtype,
            crs=crs,
            transform=imgaff,
        ) as dst:
            dst.write(img, 1)
        res = [ram.getvalue(), None, None]
    elif fmt == "geojson":
        res = format_geojson_response(*mod.geojson(ctx))
    else:
        res = mod.plotter(ctx)
    # res should be either a 2 or 3 length tuple, rectify this otherwise
    if not isinstance(res, list | tuple):
        res = [res, None, None]
    if len(res) == 2:
        res = [res[0], res[1], None]
    return res, meta


def plot_metadata(fig, start_time, p):
    """Place timestamp on the image"""
    now = utc().astimezone(ZoneInfo("America/Chicago"))
    fig.text(
        0.01,
        0.005,
        f"Generated at {now:%-d %b %Y %-I:%M %p %Z} in "
        f"{((utc() - start_time).total_seconds()):.2f}s",
        va="bottom",
        ha="left",
        fontsize=8,
    )
    fig.text(
        0.99,
        0.005,
        f"IEM Autoplot App #{p}",
        va="bottom",
        ha="right",
        fontsize=8,
    )


def get_mckey(scriptnum, fdict: dict, fmt: str):
    """Figure out what our memcache key should be."""
    vals = []
    for key in fdict:
        # Internal app controls should not be used on the memcache key
        # except when they should be, sigh
        if not key.startswith("_") or key in ["_r", "_"]:
            vals.append(f"{key}:{fdict[key]}")  # noqa
    mckey = (
        f"/plotting/auto/plot/{scriptnum}/{'::'.join(vals)}.{fmt}"
    ).replace(" ", "")
    # If the key does not decode to ascii, this is likely a naughty request
    try:
        mckey.encode("ascii")
    except UnicodeEncodeError as exp:
        raise BadWebRequest("Memcache key is non-ASCII") from exp

    return mckey


def workflow(mc, environ: dict, fmt: str):
    """we need to return a status and content"""
    # q is the full query string that was rewritten to use by apache
    q = environ.get("q", "")
    fdict = parser(q)
    # p=number is the python backend code called by this framework
    scriptnum = int(environ["p"])
    fdict["dpi"] = max(min([int(float(fdict.get("dpi", 100))), 500]), 50)

    # memcache keys can not have spaces
    mckey = get_mckey(scriptnum, fdict, fmt)
    if len(mckey) < 250:
        # Don't fetch memcache when we have _cb set for an inbound CGI
        res = mc.get(mckey) if fdict.get("_cb") is None else None
        if res:
            return HTTP200, res
    # memcache failed to save us work, so work we do!
    start_time = utc()
    # res should be a 3 length tuple
    try:
        res, meta = get_res_by_fmt(scriptnum, fmt, fdict)
    except (IncompleteWebRequest, NoDataFound, UnknownStationException) as exp:
        return HTTP400, handle_error(exp, fmt, environ)
    except BadWebRequest as exp:
        raise BadWebRequest("") from exp
    except Exception as exp:
        # Log this so that my review scripts see it.
        write_telemetry(
            TELEMETRY(
                (utc() - start_time).total_seconds(),
                500,
                # In testing, perhaps both could be None
                environ.get(
                    "X-Forwarded-For", environ.get("REMOTE_ADDR", "127.0.0.1")
                )
                .split(",")[0]
                .strip(),
                environ.get("SCRIPT_NAME"),
                environ.get("REQUEST_URI"),
                environ.get("HTTP_HOST"),
            )
        )
        # Everything else should be considered fatal
        return HTTP500, handle_error(exp, fmt, environ)

    [mixedobj, df, report] = res
    # Our output content
    content = ""
    if fmt == "js" and isinstance(mixedobj, dict):
        content = f'Highcharts.chart("ap_container", {json.dumps(mixedobj)});'
    elif fmt in ["js", "geojson", "geotiff"]:
        content = mixedobj
    elif fmt in ["svg", "png", "pdf"]:
        if isinstance(mixedobj, mpl.figure.Figure):
            # if our content is a figure, then add some fancy metadata to plot
            if meta.get("plotmetadata", True):
                plot_metadata(mixedobj, start_time, scriptnum)
            ram = BytesIO()
            mixedobj.savefig(ram, format=fmt, dpi=fdict["dpi"])
            mixedobj.clear()
            ram.seek(0)
            content = ram.read()
        elif isinstance(mixedobj, Image.Image):
            ram = BytesIO()
            mixedobj.save(ram, fmt)
            ram.seek(0)
            content = ram.read()

        elif mixedobj is None:
            return (
                HTTP400,
                error_image(
                    ("plot requested but backend does not support plots"), fmt
                ),
            )
    elif fmt == "txt" and report is not None:
        content = report
    elif fmt in ["csv", "txt", "xlsx"] and df is not None:
        # If the index is a datetime object, we need to convert it to a string
        if isdt(df.index):
            dtz = df.index.tz
            # We could have timezone or zoneinfo :/
            if dtz is not None and dtz in [
                ZoneInfo("UTC"),
                timezone.utc,
            ]:
                df.index = df.index.strftime(ISO8601)
            else:
                df.index = df.index.strftime("%Y-%m-%dT%H:%M:%S")
        # Dragons: do timestamp conversion as pandas has many bugs
        for column in df.columns:
            if isdt(df[column]):
                # Careful, only use ISO format when the timezone is UTC
                dtz = df[column].dt.tz
                # We could have timezone or zoneinfo :/
                if dtz is not None and dtz in [
                    ZoneInfo("UTC"),
                    timezone.utc,
                ]:
                    df[column] = df[column].dt.strftime(ISO8601)
                else:
                    df[column] = df[column].dt.strftime("%Y-%m-%dT%H:%M:%S")

        if fmt in ["csv", "txt"]:  # Meh on the txt here
            content = df.to_csv(index=(df.index.name is not None), header=True)
        elif fmt == "xlsx":
            # Can't write to ram buffer yet, unimplmented upstream
            (_, tmpfn) = tempfile.mkstemp()
            df.index.name = None
            # Need to set engine as xlsx/xls can't be inferred
            with pd.ExcelWriter(tmpfn, engine="openpyxl") as writer:
                df.to_excel(writer, sheet_name="Sheet1")
            with open(tmpfn, "rb") as fh:
                content = fh.read()
            os.unlink(tmpfn)
    else:
        error_log(
            environ,
            f"Undefined edge case: fmt: {fmt} "
            f"uri: {environ.get('REQUEST_URI')}",
        )
        return HTTP422, "Undefined edge case encountered"

    dur = int(meta.get("cache", 43200))
    try:
        # we have a 10 MB limit within memcache, so don't write objects bigger
        if len(content) < 9.5 * 1024 * 1024:
            # Default encoding is ascii for text
            mc.set(
                mckey.encode("ascii"),
                (
                    content
                    if isinstance(content, bytes)
                    else content.encode("utf-8")
                ),
                dur,
            )
        else:
            error_log(
                environ,
                f"Memcache object too large: {len(content)} "
                f"uri: {environ.get('REQUEST_URI')}",
            )
    except UnicodeEncodeError as exp:
        raise BadWebRequest("Memcache key is non-ASCII") from exp
    except Exception as exp:
        error_log(environ, f"Exception while writting key: {mckey} {exp}")
    if isinstance(mixedobj, mpl.figure.Figure):
        mixedobj.clear()
    syslog.syslog(
        syslog.LOG_LOCAL1 | syslog.LOG_INFO,
        f"Autoplot[{scriptnum:3.0f}] "
        f"Timing: {(utc() - start_time).total_seconds():.3f}s "
        f"Key: {mckey} Cache: {dur}[s]",
    )
    return HTTP200, content


@iemapp(parse_times=False, allowed_as_list=["ltype"])
def application(environ, start_response):
    """Our Application!"""
    if "p" not in environ:
        raise IncompleteWebRequest("GET parameter p is missing.")
    # Parse the request that was sent our way
    # HACK
    qstr = environ.get("q", "")
    if qstr.find("network:WFO::wfo:PHEB") > -1:
        environ["q"] = qstr.replace("network:WFO", "network:NWS")
    if qstr.find("network:WFO::wfo:NHC") > -1:
        environ["q"] = qstr.replace("network:WFO", "network:NCEP")
    if qstr.find("network:WFO::wfo:PAAQ") > -1:
        environ["q"] = qstr.replace("network:WFO", "network:NWS")
    if qstr.find("network:AWOS") > -1:
        environ["q"] = qstr.replace("network:AWOS", "network:IA_ASOS")
    # Figure out the format that was requested from us, default to png
    fmt = environ.get("fmt", "png")[:7]
    mc = Client("iem-memcached:11211")
    try:
        # do the work!
        status, output = workflow(mc, environ, fmt)
    except BadWebRequest as exp:
        raise BadWebRequest("") from exp
    except Exception as exp:
        status = HTTP500
        output = handle_error(exp, fmt, environ)
    finally:
        mc.close()
    # Special case for when we are returning a javascript alert
    if fmt == "js" and status == HTTP400:
        start_response(HTTP200, get_response_headers(status, fmt))
        return [output.encode("utf-8")]
    # Figure out what our response headers should be
    start_response(status, get_response_headers(status, fmt))
    if isinstance(output, str):
        output = output.encode("UTF-8")
    return [output]
