import pdfplumber
import os
import re
import unicodedata


def _sin_tildes(texto: str) -> str:
    """Quita tildes/diacríticos para comparaciones tolerantes a variaciones de formato."""
    return "".join(c for c in unicodedata.normalize("NFKD", texto) if not unicodedata.combining(c))


TIPO_MAP = {
    "FACTURA": "01",
    "BOLETA": "03",
    "GUIA DE REMISION": "09",
    "GUIA DE REMISION TRANSPORTISTA": "31",
}


# ============================================================================
# HELPERS INTERNOS (desde leer_pdf.py)
# ============================================================================

def _extract_name_ruc(text_input: str) -> tuple[str | None, str | None]:
    if not text_input: return None, None
    full_s = " ".join(text_input.split()).strip()
    name, ruc = full_s, None
    if " - " in full_s:
        name = full_s.split(" - ")[0].strip()
        r_match = re.search(r"(\d{11})", full_s)
        if r_match:
            ruc = r_match.group(1)
    return name, ruc

# ============================================================================

def _extract_base_data(text: str, pdf_path: str) -> dict:
    basename = os.path.basename(pdf_path)
    data = {
        "archivo": basename,
        "ruc_emisor": None,
        "tipo_documento": None,
        "serie_numero": None,
        "fecha_emision": None,
        "ruc_receptor": None,
        "nombre_receptor": None,
        "monto_total": None,
    }
    ruc_match = re.search(r"R\.U\.C\.?\s*(\d{11})", text, re.IGNORECASE)
    if ruc_match:
        data["ruc_emisor"] = ruc_match.group(1)
    else:
        if "-" in basename:
            parts = basename.split('-')
            if len(parts[0]) == 11 and parts[0].isdigit():
                data["ruc_emisor"] = parts[0]
        if not data["ruc_emisor"]:
            standalone_ruc = re.search(r"(\d{11})", text)
            if standalone_ruc:
                data["ruc_emisor"] = standalone_ruc.group(1)

    text_norm = _sin_tildes(text.upper())
    if "FACTURA ELECTRONICA" in text_norm:
        data["tipo_documento"] = "FACTURA"
    elif "BOLETA DE VENTA" in text_norm:
        data["tipo_documento"] = "BOLETA"
    elif "TRANSPORTISTA" in text_norm and "GUIA DE REMISION" in text_norm:
        data["tipo_documento"] = "GUIA DE REMISION TRANSPORTISTA"
    elif "GUIA DE REMISION" in text_norm or "GRRE:" in text_norm:
        data["tipo_documento"] = "GUIA DE REMISION"

    serie_numero_match = re.search(r"(?:N°\s*)?([A-Z0-9]{4})\s*-\s*(\d+)", text)
    if serie_numero_match:
        data["serie_numero"] = f"{serie_numero_match.group(1)}-{serie_numero_match.group(2)}"
    elif "GRRE:" in text:
        grre_match = re.search(r"GRRE:\s*([A-Z0-9-]{4,})", text)
        if grre_match:
            data["serie_numero"] = grre_match.group(1)

    date_match = re.search(r"(\d{2})\s*[/-]\s*(\d{2})\s*[/-]\s*(\d{4})", text)
    if date_match:
        data["fecha_emision"] = f"{date_match.group(1)}/{date_match.group(2)}/{date_match.group(3)}"

    ruc_label_match = re.search(r"(?:Ruc|REGISTRO ÚNICO DE CONTRIBUYENTES N°)\s*:?\s*(\d{11})", text, re.IGNORECASE)
    if ruc_label_match and ruc_label_match.group(1) != data["ruc_emisor"]:
        data["ruc_receptor"] = ruc_label_match.group(1)
    else:
        all_rucs = re.findall(r"(?<!\d)(\d{11})(?!\d)", text)
        for r in all_rucs:
            if r != data["ruc_emisor"]:
                data["ruc_receptor"] = r
                break

    lines = text.split('\n')
    for line in lines:
        match = re.search(r"\b(?:SEÑOR\(ES\)|CLIENTE|RAZÓ?N SOCIAL|ADQUIRIENTE|DATOS DEL DESTINATARIO)\s*:?\s*(.+)", line, re.IGNORECASE)
        if match:
            name = match.group(1)
            name = re.split(r"FECHA", name, flags=re.IGNORECASE)[0]
            name = name.split("-")[0].strip()
            if len(name) > 2:
                data["nombre_receptor"] = name
                break
    return data

# ============================================================================

def _extract_factura_details(text: str, data: dict) -> None:
    amount_regex = r"((?:\d{1,3}(?:,\d{3})*|\d+)\.\d{2})"
    total_patterns = [
        rf"TOTAL\s*(?:S/|S/\.)?[:\s]*{amount_regex}",
        rf"IMPORTE TOTAL\s*(?:S/|S/\.)?[:\s]*{amount_regex}",
        rf"NETO A PAGAR\s*(?:S/|S/\.)?[:\s]*{amount_regex}",
    ]
    total_found = False
    for pattern in total_patterns:
        match = re.search(pattern, text, re.IGNORECASE)
        if match:
            data["monto_total"] = match.group(1).replace(",", "")
            total_found = True
            break
    if not total_found:
        amounts = re.findall(amount_regex, text)
        if amounts:
            data["monto_total"] = amounts[-1].replace(",", "")

    data.update({
        "items": [],
        "detraccion": {"tiene": False, "porcentaje": None, "monto": None},
    })

    lines = text.split('\n')
    table_start_index = -1
    for i, line in enumerate(lines):
        line_up = line.upper()
        headers_found = sum(1 for h in ["CANT", "DESCRIP", "PRECIO", "TOTAL", "UNIT", "VALOR", "CÓDIGO", "ITEM"] if h in line_up)
        if headers_found >= 3:
            table_start_index = i
            break

    if table_start_index != -1:
        items_lines = lines[table_start_index + 1:]
        current_item = None
        pre_item_buffer = []
        for line in items_lines:
            line = line.strip()
            if not line: continue
            if re.search(r"^(?:SUB|TOTAL|IGV|SON:|OP\.|RES|CUO|DET|BANCO|Representación|Podrá|Autorizado|FORMA|CUOTA|GRAVADO|I\.G\.V\.|DESEMBOLSO|OBSERVACION)", line, re.IGNORECASE):
                break
            amounts = re.findall(r"(?<![A-Z0-9-])(\d+(?:,\d{3})*(?:\.\d{2,}))(?:(?=\s)|(?=$)|(?=[A-Z][a-z]))", line)
            if len(amounts) >= 2:
                if current_item: data["items"].append(current_item)
                qty = amounts[0]
                p_unit = amounts[-2].replace(",", "")
                total = amounts[-1].replace(",", "")
                desc_line = line
                seen = set()
                for amt in amounts:
                    if amt not in seen:
                        desc_line = desc_line.replace(amt, "", 1)
                        seen.add(amt)
                desc_parts = [p.strip() for p in desc_line.split() if p.strip()]
                cod = None
                for j in range(min(3, len(desc_parts))):
                    if re.search(r"[A-Z].*\d|\d.*[A-Z]|[A-Z]{2,}-\d+", desc_parts[j]):
                        cod = desc_parts[j]
                        desc_parts.pop(j)
                        break
                if desc_parts and desc_parts[0].isdigit() and len(desc_parts[0]) <= 2:
                    desc_parts.pop(0)
                descripcion = " ".join(desc_parts)
                current_item = {
                    "codigo": cod,
                    "cantidad": qty,
                    "descripcion": descripcion,
                    "precio_unitario": p_unit,
                    "total": total,
                    "guias_remision": [],
                    "guia_transportista": None,
                    "bolsas": None,
                    "peso": None,
                    "unidad_peso": None,
                }
                if pre_item_buffer:
                    current_item["descripcion"] = " ".join(pre_item_buffer) + " " + descripcion
                    pre_item_buffer = []
            elif current_item and len(line) > 5:
                current_item["descripcion"] += " " + line
            elif not current_item and len(line) > 5:
                pre_item_buffer.append(line)
        if current_item: data["items"].append(current_item)

    # Extraer guías de cada ítem usando los mismos patrones que sunat_schema
    GUIAS_PDF_PATTERNS = [
        (r"(?:GRE\s+REMITENTE|GRR|G\.R\.R)\s*[:.]?\s*([TVE][A-Z0-9]{3,4})\s*-?\s*(\d+)", "09"),
        (r"\b(?:GRT|G\.R\.T)\s*[:.]?\s*([TVE][A-Z0-9]{3,4})\s*-?\s*(\d+)", "31"),
    ]
    for item in data["items"]:
        desc = item["descripcion"]
        for patron, tipo in GUIAS_PDF_PATTERNS:
            for m in re.finditer(patron, desc, re.IGNORECASE):
                numero = m.group(2).lstrip("0") or "0"
                if tipo == "09":
                    item["guias_remision"].append(f"{m.group(1).upper()}-{numero}")
                else:
                    item["guia_transportista"] = f"{m.group(1).upper()}-{numero}"
        bolsas_match = re.search(r"(\d+)\s*(?:BOLSAS|BLS|BOLS|SACOS)\b", desc, re.IGNORECASE)
        if bolsas_match:
            item["bolsas"] = bolsas_match.group(1)
        peso_match = re.search(r"(?:PESO(?: TOTAL)?|CARGA)\s*(?:(TN|KG|KILOS?))?\.?\s*[:\s]\s*([\d,.]+)\s*(TN|KG|KILOS?)?", desc, re.IGNORECASE)
        if peso_match:
            item["peso"] = peso_match.group(2).strip()
            item["unidad_peso"] = (peso_match.group(1) or peso_match.group(3) or "").upper()

    det = data["detraccion"]
    if re.search(r"\bDETRACC(?:I[OÓ]N|\.)", text, re.IGNORECASE):
        det["tiene"] = True
        pct_match = re.search(r"PORCENTAJE\s*[:/]\s*([\d.]+)\s*%", text, re.IGNORECASE)
        if not pct_match:
            pct_match = re.search(r"DETRACC[^\n]*?([\d]+(?:\.\d+)?)\s*%", text, re.IGNORECASE)
        if pct_match:
            det["porcentaje"] = pct_match.group(1)
        monto_match = re.search(
            r"(?:MONTO\s*(?:DETRACC\.?|DE\s*DETRACCI[OÓ]N)|Monto\s*Detracc\.?)\s*[:/]?\s*S/\.?\s*([\d,.]+)",
            text, re.IGNORECASE,
        )
        if not monto_match:
            monto_match = re.search(r"MONTO\s*DETRACC\w*[:\s]+S?/?\.?\s*([\d,.]+)", text, re.IGNORECASE)
        if not monto_match:
            monto_match = re.search(r"DETRACCION\s+\d+%\s+([\d.]+)", text, re.IGNORECASE)
        if monto_match:
            raw = monto_match.group(1).replace(",", "")
            try:
                det["monto"] = f"{float(raw):.2f}"
            except ValueError:
                det["monto"] = raw

# ============================================================================

def _extract_guia_remision_details(text: str, data: dict) -> None:
    data.update({
        "peso_total": None, "punto_partida": None, "punto_llegada": None, "placa": None,
        "marca": None, "chofer": None, "brevete": None, "configuracion_vehicular": None, "items": [],
    })
    peso_match = re.search(r"Peso Total (?:TN|KG)?:\s*([\d,.]+)", text, re.IGNORECASE)
    if not peso_match:
        peso_match = re.search(r"Peso Total:\s*([\d,.]+)", text, re.IGNORECASE)
    if peso_match:
        data["peso_total"] = peso_match.group(1)
    conf = re.search(r"(?:Configuración vehicular|C\. Vehc\.?):\s*([A-Z0-9/]+)", text, re.IGNORECASE)
    if conf: data["configuracion_vehicular"] = conf.group(1).strip()
    for field, pattern in {
        "placa": r"Placa:\s*([A-Z0-9\s/]+?)(?=\s*(?:C\.|Marca|Peso|$))",
        "marca": r"Marca:\s*([A-Z0-9\s-]+?)(?=\s*(?:Placa|Chofer|Peso|$))",
        "chofer": r"Chofer:\s*([A-Z\s.-]+?)(?=\s*(?:Brevete|Placa|Peso|$))",
        "brevete": r"Brevete:\s*([A-Z0-9]+)",
    }.items():
        match = re.search(pattern, text, re.IGNORECASE)
        if match: data[field] = match.group(1).strip()
    p_match = re.search(r"Punto de Partida:\s*(.*?)\s*Punto de Llegada:", text, re.DOTALL | re.IGNORECASE)
    if p_match: data["punto_partida"] = " ".join(p_match.group(1).split()).strip()
    l_match = re.search(r"Punto de Llegada:\s*(.*?)\s*(?:Fecha de inicio|T[0-9]{3}-|$)", text, re.DOTALL | re.IGNORECASE)
    if l_match: data["punto_llegada"] = " ".join(l_match.group(1).split()).strip()
    header = re.search(r"(?:CANT|CANTIDAD)\s+(?:UN|UNIDAD)\s+(?:DESCRIPCIÓN|DESCRIPCION|DETALLE)", text, re.IGNORECASE)
    if header:
        items_text = text[header.end():].split("Peso Aprox")[0]
        current_item = None
        for line in items_text.split('\n'):
            line = line.strip()
            if not line or re.search(r"^(?:Peso Aprox|Punto de|Fecha de|Representación|Placa|Chofer|C\. Vehc)", line, re.IGNORECASE):
                continue
            match = re.match(r"^(\d+(?:\.\d+)?)\s+([A-Z]{2,3})\s+(.+)", line)
            if match:
                if current_item: data["items"].append(current_item)
                current_item = {"cantidad": match.group(1), "unidad": match.group(2), "descripcion": match.group(3).strip()}
            elif current_item:
                current_item["descripcion"] += " " + line
        if current_item: data["items"].append(current_item)

# ============================================================================

def _extract_guia_transportista_details(text: str, data: dict) -> None:
    data.update({
        "punto_partida": None, "punto_llegada": None, "nombre_remitente": None, "ruc_remitente": None,
        "nombre_destinatario": None, "ruc_destinatario": None, "documentos_relacionados": [],
        "unidad_medida_peso_bruto": None, "peso_bruto_total_carga": None, "indicador_pagador_flete": None,
        "nombre_pagador": None, "ruc_pagador": None, "datos_vehiculos": [], "datos_conductores": [], "observaciones": None,
    })
    p_match = re.search(r"Punto de Partida:\s*(.*?)\s*Punto de llegada:", text, re.DOTALL | re.IGNORECASE)
    if p_match: data["punto_partida"] = " ".join(p_match.group(1).split()).strip()
    l_match = re.search(r"Punto de llegada:\s*(.*?)\s*Datos del remitente:", text, re.DOTALL | re.IGNORECASE)
    if l_match: data["punto_llegada"] = " ".join(l_match.group(1).split()).strip()
    rem_match = re.search(r"Datos del remitente:\s*(.*?)\s*Datos del destinatario:", text, re.DOTALL | re.IGNORECASE)
    if rem_match: data["nombre_remitente"], data["ruc_remitente"] = _extract_name_ruc(rem_match.group(1))
    dest_match = re.search(r"Datos del destinatario:\s*(.*?)\s*Documentos Relacionados:", text, re.DOTALL | re.IGNORECASE)
    if dest_match: data["nombre_destinatario"], data["ruc_destinatario"] = _extract_name_ruc(dest_match.group(1))
    pag_match = re.search(r"Datos de pagador de flete:\s*(.*?)\s*(?:Observaciones|Esta es|$)", text, re.DOTALL | re.IGNORECASE)
    if pag_match: data["nombre_pagador"], data["ruc_pagador"] = _extract_name_ruc(pag_match.group(1))
    rel_match = re.search(r"Documentos Relacionados:\s*(.*?)\s*(?:Bienes por Transportar|Datos de|$)", text, re.DOTALL | re.IGNORECASE)
    if rel_match:
        for line in rel_match.group(1).split('\n'):
            line = line.strip()
            if not line: continue
            doc = re.search(r"(?:N°\s*)([A-Z0-9\s-]+)- RUC N°\s*(\d{11})", line, re.IGNORECASE)
            data["documentos_relacionados"].append({"documento": doc.group(1).strip(), "ruc_relacionado": doc.group(2)} if doc else line)
    u_match = re.search(r"Unidad de Medida del Peso Bruto:\s*(\w+)", text, re.IGNORECASE)
    if u_match: data["unidad_medida_peso_bruto"] = u_match.group(1)
    p_match = re.search(r"Peso Bruto total de la carga:\s*([\d,.]+)", text, re.IGNORECASE)
    if p_match: data["peso_bruto_total_carga"] = p_match.group(1)
    ind_match = re.search(r"Indicador del pagador del flete:\s*(\w+)", text, re.IGNORECASE)
    if ind_match: data["indicador_pagador_flete"] = ind_match.group(1)
    v_match = re.search(r"Datos de los vehículos:\s*(.*?)\s*Datos de los conductores:", text, re.DOTALL | re.IGNORECASE)
    if v_match: data["datos_vehiculos"] = [{"placa": p} for p in re.findall(r"Número de placa:\s*([A-Z0-9]+)", v_match.group(1), re.IGNORECASE)]
    c_match = re.search(r"Datos de los conductores:\s*(.*?)\s*(?:Datos de pagador|Observaciones|$)", text, re.DOTALL | re.IGNORECASE)
    if c_match:
        c_text = c_match.group(1)
        data["datos_conductores"] = [{"nombre": n.strip()} for n in re.findall(r"Principal:\s*([A-Z\s-]+)(?:\s*-|$)", c_text, re.IGNORECASE)]
        for i, b in enumerate(re.findall(r"Número de lincencia de conducir:\s*([A-Z0-9]+)", c_text, re.IGNORECASE)):
            if i < len(data["datos_conductores"]): data["datos_conductores"][i]["brevete"] = b
    obs = re.search(r"Observaciones\s*:\s*(.*?)(?=\s*(?:Esta es|$))", text, re.IGNORECASE | re.DOTALL)
    if obs: data["observaciones"] = obs.group(1).strip()

# ============================================================================

def _extract_detraccion_spatial(pdf, data: dict) -> None:
    det = data.get("detraccion", {})
    if not det.get("tiene"):
        return
    if det.get("porcentaje") and det.get("monto"):
        return
    for page in pdf.pages:
        words = page.extract_words()
        if not words:
            continue
        det_words = [w for w in words if re.search(r"Detrac", w["text"], re.IGNORECASE)]
        if not det_words:
            continue
        region_text = None
        for rect in (page.rects or []):
            for dw in det_words:
                if (rect["x0"] <= dw["x0"] <= rect["x1"] and
                        rect["top"] <= dw["top"] <= rect["bottom"]):
                    cropped = page.crop((rect["x0"], rect["top"], rect["x1"], rect["bottom"]))
                    region_text = cropped.extract_text() or ""
                    break
            if region_text:
                break
        if not region_text and det_words:
            dw = det_words[0]
            cropped = page.crop((0, max(0, dw["top"] - 30), page.width, min(page.height, dw["bottom"] + 80)))
            region_text = cropped.extract_text() or ""
        if not region_text:
            continue
        if not det.get("porcentaje"):
            pct = re.search(r"(\d+(?:\.\d+)?)\s*%\s*Detrac", region_text, re.IGNORECASE)
            if not pct:
                pct = re.search(r"PORCENTAJE\s*[:/]\s*(\d+(?:\.\d+)?)\s*%", region_text, re.IGNORECASE)
            if pct:
                try:
                    det["porcentaje"] = f"{float(pct.group(1)):.2f}"
                except ValueError:
                    det["porcentaje"] = pct.group(1)
        if not det.get("monto"):
            monto = re.search(r"Detrac[^:]*:\s*([\d,.]+)", region_text, re.IGNORECASE)
            if not monto:
                monto = re.search(r"MONTO[^:]*:\s*S?/?\.?\s*([\d,.]+)", region_text, re.IGNORECASE)
            if monto:
                raw = monto.group(1).replace(",", "")
                try:
                    det["monto"] = f"{float(raw):.2f}"
                except ValueError:
                    det["monto"] = raw
        break


# ============================================================================
# FUNCIONES PÚBLICAS
# ============================================================================

def extraer_datos_pdf(pdf_path: str) -> dict:
    try:
        with pdfplumber.open(pdf_path) as pdf:
            text = "".join(page.extract_text() or "" for page in pdf.pages)
            data = _extract_base_data(text, pdf_path)
            if data["tipo_documento"] == "FACTURA":
                _extract_factura_details(text, data)
                _extract_detraccion_spatial(pdf, data)
            elif data["tipo_documento"] == "GUIA DE REMISION":
                _extract_guia_remision_details(text, data)
            elif data["tipo_documento"] == "GUIA DE REMISION TRANSPORTISTA":
                _extract_guia_transportista_details(text, data)
            return data
    except Exception as e:
        return {"archivo": os.path.basename(pdf_path), "error": str(e)}

# ============================================================================

def generar_nombre_pdf(data: dict) -> str | None:
    ruc = data.get("ruc_emisor")
    tipo_doc = data.get("tipo_documento")
    serie_numero = data.get("serie_numero")
    if not ruc or not tipo_doc or not serie_numero:
        return None
    abrev = TIPO_MAP.get(tipo_doc.upper())
    if not abrev:
        return None
    if "-" in serie_numero:
        serie, numero = serie_numero.split("-", 1)
        numero = numero.lstrip("0") or "0"
    else:
        serie = serie_numero
        numero = ""
    return f"{ruc}-{abrev}-{serie}-{numero}.pdf"

# ============================================================================

def renombrar_pdf(pdf_path: str, data: dict) -> str:
    dirname = os.path.dirname(pdf_path)
    nuevo_nombre = generar_nombre_pdf(data)
    if not nuevo_nombre:
        return pdf_path
    nuevo_path = os.path.join(dirname, nuevo_nombre)
    if pdf_path == nuevo_path:
        return pdf_path
    try:
        os.rename(pdf_path, nuevo_path)
        return nuevo_path
    except OSError:
        return pdf_path

# ============================================================================

def _extraer_serie_numero(texto: str) -> tuple[str, str] | None:
    m = re.search(r'\b([TVE][A-Z0-9]{3})\s*-\s*(\d+)\b', texto)
    if m:
        return m.group(1).upper(), m.group(2)
    return None


def extraer_referencias(items: list) -> list:
    referencias = []
    vistos = set()
    for item in items:
        for gr_str in item.get("guias_remision", []):
            parsed = _extraer_serie_numero(gr_str)
            if not parsed:
                partes = gr_str.split("-", 1)
                if len(partes) == 2:
                    parsed = (partes[0].strip(), partes[1].strip())
                else:
                    continue
            serie, numero = parsed
            clave = f"09|{serie}|{numero}"
            if clave not in vistos:
                vistos.add(clave)
                referencias.append({"tipo": "09", "serie": serie, "numero": numero})
        gt_str = item.get("guia_transportista")
        if gt_str:
            parsed = _extraer_serie_numero(gt_str)
            if not parsed:
                partes = gt_str.split("-", 1)
                if len(partes) == 2:
                    parsed = (partes[0].strip(), partes[1].strip())
                else:
                    continue
            serie, numero = parsed
            clave = f"31|{serie}|{numero}"
            if clave not in vistos:
                vistos.add(clave)
                referencias.append({"tipo": "31", "serie": serie, "numero": numero})
    return referencias