import csv
import sys
import re
import subprocess as sp
from datetime import datetime
from pathlib import Path
from typing import NamedTuple


class CsvRow(NamedTuple):
    year: int
    species: str
    unit: str
    average_lower: float
    average_upper: float
    min_lower: float
    min_upper: float
    max_lower: float
    max_upper: float
    limit: float


def fmt_float(x: str) -> float:
    if x == "n/d" or x == "n.d":
        return 0
    else:
        # spaces sometimes show up if there is a superscript
        return float(x.split(" ")[0])


def fmt_lt(x: str) -> tuple[float, float]:
    if "<" == x[0]:
        return (0, fmt_float(x.removeprefix("<")))
    else:
        return (y := fmt_float(x), y)


def parse_chemical(year, line: list[str]) -> CsvRow:
    try:
        limit = float(re.match("\d+(\.\d+)?", line[5])[0])
    except (TypeError, ValueError, IndexError):
        limit = -1
    a = fmt_lt(line[2])
    mx = fmt_lt(line[3])
    mi = fmt_lt(line[4])
    return CsvRow(
        year=year,
        species=line[0],
        unit=line[1].replace("µ", "u"),
        average_lower=a[0],
        average_upper=a[1],
        min_lower=mi[0],
        min_upper=mi[1],
        max_lower=mx[0],
        max_upper=mx[1],
        limit=limit,
    )


def parse_pdf(year: int, ipath: Path) -> list[CsvRow]:
    res = sp.run(
        ["pdftotext", "-f", "1", "-l", "4", "-r", "1000", "-layout", ipath, "-"],
        capture_output=True,
    )
    if res.returncode == 0:
        lns = [
            l.strip()
            for l in res.stdout.decode().splitlines()
            if "/L" in l and not " of " in l and not " sample" in l
        ]
        chemicals = [
            s
            for x in lns
            if len(s := re.split("\s\s+", x)) > 2 and "Total Organic Carbon" not in s[0]
        ]
        return [parse_chemical(year, c) for c in chemicals]
    else:
        assert False, res.stderr


def main(year: int, ipath: str, opath: str) -> None:
    rows = parse_pdf(year, ipath)
    with open(opath, "w") as f:
        w = csv.writer(f, delimiter="\t")
        for r in rows:
            w.writerow(r)


main(snakemake.wildcards["year"], snakemake.input[0], snakemake.output[0])