import json
import random
import re
import shutil
from pathlib import Path

from openpyxl import load_workbook
from openpyxl.worksheet.worksheet import Worksheet

from legex.config import settings
from legex.models.base import Case
from legex.scrapers import SCRAPERS


def raw_path(cc: str) -> Path:
    return settings.raw_dir / f"{cc}.jsonl"


def filtered_path(cc: str) -> Path:
    return settings.processed_dir / f"{cc}_filtered.jsonl"


def sampled_path(cc: str) -> Path:
    return settings.processed_dir / f"{cc}_sampled.jsonl"


# Names like:
#   Goldenset_Australia.xlsx
#   Goldenset_Hong_Kong_final.xlsx
#   Goldenset_Brazil_final (datalocation_...).xlsx
#   Georgia_Goldenset_final.xlsx
_GOLDENSET_NAME_PATTERNS = (
    re.compile(r"^Goldenset_(.+?)(?:_final.*)?\.xlsx$"),
    re.compile(r"^(.+?)_Goldenset(?:_final.*)?\.xlsx$"),
)


def _country_from_goldenset_filename(name: str) -> str | None:
    for pat in _GOLDENSET_NAME_PATTERNS:
        m = pat.match(name)
        if m:
            return m.group(1).strip()
    return None


def _existing_goldenset_files(cc: str) -> list[Path]:
    d = settings.data_dir / cc
    if not d.is_dir():
        return []
    return sorted(d.glob("*Goldenset*.xlsx"))


def _preferred_goldenset_file(cc: str) -> Path | None:
    files = _existing_goldenset_files(cc)
    finals = [f for f in files if "final" in f.stem.lower()]
    return (finals or files or [None])[0]


def _country_for(cc: str) -> str:
    """Country name used in Goldenset filenames.

    Prefers the name extracted from the same Goldenset xlsx that
    `goldenset_path` would pick, then the scraper's `country` attr, then cc.
    """
    f = _preferred_goldenset_file(cc)
    if f is not None:
        name = _country_from_goldenset_filename(f.name)
        if name:
            return name
    scraper = SCRAPERS.get(cc)
    if scraper is not None:
        return getattr(scraper, "country", cc)
    return cc


def countries_with_goldenset() -> list[str]:
    """Country codes that have a Goldenset xlsx under data/<cc>/."""
    if not settings.data_dir.is_dir():
        return []
    return sorted(
        d.name for d in settings.data_dir.iterdir() if d.is_dir() and _existing_goldenset_files(d.name)
    )


# Round-2 submission layout: JSONL gold + inference_<system>.csv per jurisdiction.
EXCLUDED_FOR_EVAL: frozenset[str] = frozenset(
    {"tw", "br", "hk", "in", "rs", "np", "be"}
)


def goldenset_jsonl_path(cc: str) -> Path:
    """Submission-style gold path: data/<cc>/goldenset_<cc>.jsonl."""
    return settings.data_dir / cc / f"goldenset_{cc}.jsonl"


def inference_csv_path(cc: str, system: str) -> Path:
    """Submission-style prediction path: data/<cc>/inference_<system>.csv.

    `system` is one of `harvey`, `gemini`, `gpt`.
    """
    return settings.data_dir / cc / f"inference_{system}.csv"


def countries_with_goldenset_jsonl() -> list[str]:
    """Country codes that have a submission-style goldenset_<cc>.jsonl on disk."""
    if not settings.data_dir.is_dir():
        return []
    return sorted(
        d.name for d in settings.data_dir.iterdir()
        if d.is_dir() and goldenset_jsonl_path(d.name).exists()
    )


def evaluable_countries() -> list[str]:
    """countries_with_goldenset_jsonl() minus the round-2 exclusion set."""
    return [cc for cc in countries_with_goldenset_jsonl() if cc not in EXCLUDED_FOR_EVAL]


def goldenset_path(cc: str) -> Path:
    f = _preferred_goldenset_file(cc)
    if f is not None:
        return f
    return settings.data_dir / cc / f"Goldenset_{_country_for(cc)}.xlsx"


def goldenset_sheet(wb) -> Worksheet:
    """Return the GOLDENSET worksheet, tolerating names like 'GOLDENSET (2)'."""
    if "GOLDENSET" in wb.sheetnames:
        return wb["GOLDENSET"]
    for name in wb.sheetnames:
        if name.upper().startswith("GOLDENSET"):
            return wb[name]
    raise ValueError(f"workbook has no GOLDENSET sheet, found {wb.sheetnames}")


def full_text_jsonl_path(cc: str) -> Path:
    """Optional per-case full_text source at data/<cc>/full_text.jsonl.

    Used as a fallback when the GOLDENSET xlsx full_text column is missing
    or empty (e.g. for jurisdictions where the text is too large for Excel
    or only available via scraping).
    """
    return settings.data_dir / cc / "full_text.jsonl"


_CASE_ID_SEP_RE = re.compile(r"[\s/\\\-._;]+")


def norm_case_id(s: str) -> str:
    """Loose case_id key for matching across sources.

    Different sources use different separators (spaces, slashes, dots, dashes,
    underscores) for the same id — e.g. xlsx `G.R. No. 266431` vs jsonl PDF
    stem `G.R._No._266431`. Collapse all of those to a single underscore and
    lowercase so the two compare equal.
    """
    return _CASE_ID_SEP_RE.sub("_", s.strip()).strip("_").lower()


def read_full_text_jsonl(cc: str) -> dict[str, str]:
    """case_id -> full_text from data/<cc>/full_text.jsonl, or {} if absent.

    Both the original case_id and its [[norm_case_id]] form are inserted as
    keys so callers can look up by either. Normalized keys never overwrite
    raw keys.
    """
    path = full_text_jsonl_path(cc)
    if not path.exists():
        return {}
    out: dict[str, str] = {}
    norm_extras: dict[str, str] = {}
    with open(path, encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            if not line:
                continue
            d = json.loads(line)
            cid = d.get("case_id")
            text = d.get("full_text")
            if cid is None or not text:
                continue
            cid_s = str(cid)
            out[cid_s] = str(text)
            norm_extras.setdefault(norm_case_id(cid_s), str(text))
    for k, v in norm_extras.items():
        out.setdefault(k, v)
    return out


def model_filename_slug(model: str) -> str:
    """litellm model id → safe filename segment (e.g. gemini/gemini-3.1-flash-lite)."""
    return model.replace("/", "_").replace("\\", "_").replace(":", "_")


def classified_csv_path(cc: str, prompt_version: str, source: str, model: str) -> Path:
    """Per-country LLM output path. `source` ∈ {"full_text", "pdf"}."""
    country = _country_for(cc)
    slug = model_filename_slug(model)
    return settings.data_dir / cc / f"Goldenset_{country}_{prompt_version}_{source}_{slug}.csv"


def pdf_paths(cc: str) -> list[Path]:
    """PDFs the README places at data/<cc>/*.pdf."""
    return sorted((settings.data_dir / cc).glob("*.pdf"))


def write_jsonl(cases: list[Case], path: Path) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    with open(path, "w", encoding="utf-8") as f:
        for c in cases:
            f.write(c.model_dump_json() + "\n")


def read_jsonl(path: Path) -> list[Case]:
    with open(path, encoding="utf-8") as f:
        return [Case.model_validate_json(line) for line in f if line.strip()]


def random_sample(cases: list[Case], n: int, seed: int = 0) -> list[Case]:
    if n >= len(cases):
        return list(cases)
    return random.Random(seed).sample(cases, n)


def write_goldenset_xlsx(cases: list[Case], template: Path, output: Path) -> None:
    output.parent.mkdir(parents=True, exist_ok=True)
    shutil.copyfile(template, output)
    wb = load_workbook(output)
    if "GOLDENSET" not in wb.sheetnames:
        raise ValueError(f"Template has no GOLDENSET sheet, found {wb.sheetnames}")
    ws = wb["GOLDENSET"]
    for i, case in enumerate(cases[:130]):
        ws.cell(row=i + 2, column=1, value=case.case_id)
        ws.cell(row=i + 2, column=2, value=case.link)
        # Column C is called full_text. Excel cell limit 32767 chars, thus we have to cut of for the labeling.
        if case.full_text:
            ws.cell(row=i + 2, column=3, value=case.full_text[:32000])
    wb.save(output)


def load_coding_rules(template: Path) -> list[tuple[str, str]]:
    wb = load_workbook(template, read_only=True, data_only=True)
    if "Variables_Coding_Rules" not in wb.sheetnames:
        raise ValueError(
            f"{template} has no Variables_Coding_Rules sheet, found {wb.sheetnames}"
        )
    ws = wb["Variables_Coding_Rules"]
    rules: list[tuple[str, str]] = []
    for row in ws.iter_rows(min_row=2, max_col=2, values_only=True):
        variable, explanation = row
        if not variable:
            continue
        rules.append((str(variable), str(explanation or "")))
    return rules


def load_goldenset_columns(template: Path) -> list[str]:
    """Header row of the GOLDENSET sheet — defines the column order."""
    wb = load_workbook(template, read_only=True, data_only=True)
    if "GOLDENSET" not in wb.sheetnames:
        raise ValueError(f"{template} has no GOLDENSET sheet, found {wb.sheetnames}")
    ws = wb["GOLDENSET"]
    header = next(ws.iter_rows(min_row=1, max_row=1, values_only=True))
    return [str(c) for c in header if c]


def load_isic_categories(template: Path) -> list[tuple[str, str, str]]:
    wb = load_workbook(template, read_only=True, data_only=True)
    if "ISIC_Level1_Categories" not in wb.sheetnames:
        raise ValueError(
            f"{template} has no ISIC_Level1_Categories sheet, found {wb.sheetnames}"
        )
    ws = wb["ISIC_Level1_Categories"]
    rows = list(ws.iter_rows(min_row=1, max_col=4, values_only=True))
    categories: list[tuple[str, str, str]] = []
    for row in rows:
        _isic_code, coded_value, category, description = row
        if not coded_value or coded_value == "Coded Value":
            continue
        categories.append((str(coded_value), str(category or ""), str(description or "")))
    return categories