import pandas as pd
import re
import unicodedata

# --- helper normalization ---
def norm_txt(x: str) -> str:
    if x is None:
        return ""
    x = unicodedata.normalize("NFKC", str(x))
    x = x.lower()
    x = re.sub(r"\s+", " ", x).strip()
    x = re.sub(r"[-‐–—]", " ", x)
    return x

class VocabularyAnalyser:
    def __init__(self, glossary_file: str):
        # Load glossary CSV (first column = base + variants, comma-separated)
        raw = pd.read_csv(glossary_file)

        gloss_list = []
        for idx, row in raw.iterrows():
            forms = []
            for cell in row:
                if pd.isna(cell):
                    continue
                for chunk in str(cell).split(","):
                    token = norm_txt(chunk)
                    if token:
                        forms.append(token)

            if not forms:
                continue

            base = forms[0]
            for form in forms:
                gloss_list.append({
                    "row": idx + 1,
                    "base": base,
                    "form": form,
                    "len": len(form),
                    "words": len(form.split())
                })

        self.gloss_forms = (
            pd.DataFrame(gloss_list)
            .drop_duplicates(["base", "form"])
            .sort_values(["words", "len"], ascending=[False, False])
        )

    def match_one_utterance(self, text: str):
        """Return list of matched base terms for a given utterance text."""
        s = norm_txt(text)
        if not s:
            return []

        locs = []
        for fm, bs, wd in zip(self.gloss_forms["form"],
                              self.gloss_forms["base"],
                              self.gloss_forms["words"]):
            if not fm:
                continue
            fm_escaped = re.escape(fm)
            pattern = r"\b" + fm_escaped + r"\b"
            for m in re.finditer(pattern, s):
                locs.append({
                    "start": m.start(),
                    "end": m.end(),
                    "form": fm,
                    "base": bs,
                    "words": wd,
                    "len": m.end() - m.start()
                })

        if not locs:
            return []

        # prioritize: more tokens > longer span > earlier start
        locs_df = pd.DataFrame(locs).sort_values(
            ["words", "len", "start"], ascending=[False, False, True]
        )

        used = [False] * len(s)
        keep_bases = []
        for _, row in locs_df.iterrows():
            rng = range(row["start"], row["end"])
            if not any(used[i] for i in rng):
                keep_bases.append(row["base"])
                for i in rng:
                    used[i] = True

        return sorted(set(keep_bases))

    def run_analysis(self, transcript):
        """Mutate transcript utterances by adding vocabulary_terms list."""
        for utt in transcript.utterances:
            matches = self.match_one_utterance(utt.text)
            utt.vocabulary_terms = matches
        return transcript