# processors/checks.py

import os
import re

from core.constants import IMAGE_EXTENSIONS, TRASH_FILES
from core.result import StepResult


def check_trash(work_dir: str) -> StepResult:
    """Detecta ficheros y directorios de basura presentes en el archivo."""
    found = []
    for root, dirs, files in os.walk(work_dir):
        for name in files:
            if name.lower() in TRASH_FILES:
                found.append(os.path.relpath(os.path.join(root, name), work_dir))
        for name in dirs:
            if name.lower() in TRASH_FILES:
                found.append(os.path.relpath(os.path.join(root, name), work_dir) + "/")

    warnings = [f"Basura detectada: {f}" for f in found]
    return StepResult(step="check_trash", changed=False, warnings=warnings)


def _natural_sort_key(name: str):
    parts = re.split(r"(\d+)", name)
    return [int(p) if p.isdigit() else p.lower() for p in parts]


def check_page_numbering(work_dir: str) -> StepResult:
    """Detecta páginas mal numeradas: sin zero-padding, padding inconsistente, saltos."""
    images = []
    for root, _, files in os.walk(work_dir):
        for f in files:
            if os.path.splitext(f)[1].lower() in IMAGE_EXTENSIONS:
                images.append(f)

    images.sort(key=lambda f: _natural_sort_key(os.path.splitext(f)[0]))
    total = len(images)
    if total == 0:
        return StepResult(step="check_page_numbering", changed=False)

    warnings = []

    # Extraer primer bloque numérico del stem de cada imagen
    numeric_values = []
    numeric_widths = []
    for img in images:
        stem = os.path.splitext(img)[0]
        m = re.search(r"(\d+)", stem)
        if m:
            numeric_values.append(int(m.group(1)))
            numeric_widths.append(len(m.group(1)))
        else:
            numeric_values.append(None)
            numeric_widths.append(None)

    has_numbers = [v for v in numeric_values if v is not None]
    if not has_numbers:
        return StepResult(step="check_page_numbering", changed=False)

    # Comprobar zero-padding si hay >= 10 imágenes
    if total >= 10:
        required_width = len(str(total))
        widths_set = set(w for w in numeric_widths if w is not None)
        if len(widths_set) > 1:
            warnings.append("Padding inconsistente entre páginas")
        elif widths_set and min(widths_set) < required_width:
            warnings.append(
                f"Páginas no zero-padded: se necesita ancho {required_width}, "
                f"encontrado {min(widths_set)}"
            )

    # Comprobar secuencia continua
    sorted_values = sorted(v for v in numeric_values if v is not None)
    if sorted_values:
        first = sorted_values[0]
        expected = list(range(first, first + len(sorted_values)))
        if sorted_values != expected:
            warnings.append("Páginas no secuenciales: hay saltos en la numeración")

    return StepResult(step="check_page_numbering", changed=False, warnings=warnings)


def check_image_extensions(work_dir: str) -> StepResult:
    """Detecta mezcla de formatos de imagen en el archivo."""
    ext_set = set()
    for root, _, files in os.walk(work_dir):
        for f in files:
            ext = os.path.splitext(f)[1].lower()
            if ext in IMAGE_EXTENSIONS:
                # Normalizar .jpeg → .jpg
                normalized = ".jpg" if ext == ".jpeg" else ext
                ext_set.add(normalized)

    warnings = []
    if len(ext_set) > 1:
        exts_str = ", ".join(sorted(ext_set))
        warnings.append(f"Extensiones de imagen mezcladas: {exts_str}")

    return StepResult(step="check_image_extensions", changed=False, warnings=warnings)


def check_comicinfo(work_dir: str) -> StepResult:
    """Detecta ausencia de ComicInfo.xml."""
    warnings = []
    found = False
    for root, _, files in os.walk(work_dir):
        for f in files:
            if f.lower() == "comicinfo.xml":
                found = True
                break
        if found:
            break

    if not found:
        warnings.append("Falta ComicInfo.xml")

    return StepResult(step="check_comicinfo", changed=False, warnings=warnings)