"""The Browse page's filter and sort.

Filter: whitespace-separated conditions that must all match, e.g.
    *Beach*  name:*Beach*  ext:png  type:image  size:>=5MB  modified:>=2026-07-01
    Colour:Orange  tag.Rating:>=2  Name:!=?
Text compares case-insensitively with shell wildcards (* ? [..]); numbers,
sizes and dates also take > >= < <= != (= is the default).

Sort: a chain of criteria (Name, Modified, Accessed, Created, FileType,
FileSize, Record, Tag:<name>), the first one deciding most. Files without
a value for a criterion always go last. Directories come before files.
"""

import os
import re
from dataclasses import dataclass, field
from datetime import datetime
from fnmatch import fnmatchcase
from functools import cmp_to_key
from pathlib import Path
from typing import Any

from Books import Book
from Library import FormatValue, TagType, Unset

ImageExtensions = {".png", ".jpg", ".jpeg", ".gif", ".bmp", ".webp"}
VideoExtensions = {".mp4", ".mkv", ".webm", ".mov", ".avi", ".m4v", ".wmv", ".flv", ".mpg", ".mpeg"}
Operators = (">=", "<=", "!=", ">", "<", "=")
SortNames = {
    "Name": "Name", "Modified": "Modified", "Accessed": "Accessed", "Created": "Created (changed)",
    "FileType": "File type", "FileSize": "File size", "Record": "Record",
}


@dataclass
class Entry:
    Path: Path
    IsDirectory: bool
    Stat: os.stat_result | None = None
    Book: Book | None = None
    BookError: str = ""
    RecordName: str = ""  # which Record it's from, when browsing a Library
    Extra: dict[str, Any] = field(default_factory=dict)

    @property
    def Kind(self) -> str:
        if self.IsDirectory:
            return "directory"
        Suffix = self.Path.suffix.lower()
        return "image" if Suffix in ImageExtensions else "video" if Suffix in VideoExtensions else "file"

    def TagValue(self, TagName: str) -> Any:
        """The value, matched case-insensitively, or None if unset."""
        if self.Book is None:
            return None
        Wanted = TagName.casefold()
        for Key, Value in self.Book.Tags.items():
            if Key.casefold() == Wanted:
                return None if Value == Unset else Value
        return None

    def TagDefinition(self, TagName: str) -> dict[str, Any]:
        if self.Book is None:
            return {}
        Wanted = TagName.casefold()
        return next((Definition for Key, Definition in self.Book.Definitions.items() if Key.casefold() == Wanted), {})


def NaturalKey(Text: str) -> tuple:
    return tuple((0, int(Part)) if Part.isdigit() else (1, Part) for Part in re.split(r"(\d+)", Text.casefold()) if Part)


# Filter

def ParseFilter(Text: str) -> list[tuple[str, str, str]]:
    """[(field, operator, value)]. Raises ValueError with a readable message."""
    Conditions = []
    for Token in Text.split():
        FieldName, RawValue = Token.split(":", 1) if ":" in Token else ("name", Token)
        if not FieldName:
            raise ValueError(f"'{Token}' is missing a field name before the colon")
        Operator = next((Candidate for Candidate in Operators if RawValue.startswith(Candidate)), "=")
        Value = RawValue[len(Operator):] if RawValue.startswith(Operator) else RawValue
        if not Value:
            raise ValueError(f"'{Token}' needs a value")
        Conditions.append((FieldName.strip(), Operator, Value.strip()))
    return Conditions


def _CompareText(Actual: str, Operator: str, Expected: str) -> bool:
    Actual, Expected = Actual.casefold(), Expected.casefold()
    if Operator in ("=", "!="):
        return fnmatchcase(Actual, Expected) == (Operator == "=")
    return {">": Actual > Expected, "<": Actual < Expected, ">=": Actual >= Expected, "<=": Actual <= Expected}[Operator]


def _CompareNumbers(Actual: float, Operator: str, Expected: float) -> bool:
    return {"=": Actual == Expected, "!=": Actual != Expected, ">": Actual > Expected, "<": Actual < Expected,
            ">=": Actual >= Expected, "<=": Actual <= Expected}[Operator]


def _ParseSize(Text: str) -> float:
    Text = Text.strip().casefold()
    for Unit, Multiplier in (("tb", 1024 ** 4), ("gb", 1024 ** 3), ("mb", 1024 ** 2), ("kb", 1024), ("b", 1)):
        if Text.endswith(Unit):
            return float(Text[:-len(Unit)].strip()) * Multiplier
    return float(Text)


def _ParseBoolean(Text: str) -> bool | None:
    Text = Text.casefold()
    return True if Text in ("true", "yes", "on", "1") else False if Text in ("false", "no", "off", "0") else None


def Matches(Item: Entry, Conditions: list[tuple[str, str, str]]) -> bool:
    return all(_MatchesOne(Item, *Condition) for Condition in Conditions)


def _MatchesOne(Item: Entry, FieldName: str, Operator: str, Expected: str) -> bool:
    Field = FieldName.casefold()
    if Field in ("name", "filename"):
        return _CompareText(Item.Path.name, Operator, Expected)
    if Field in ("extension", "ext"):
        return _CompareText(Item.Path.suffix.lstrip("."), Operator, Expected.lstrip("."))
    if Field == "type":
        return _CompareText(Item.Kind, Operator, Expected)
    if Field == "record":
        return _CompareText(Item.RecordName, Operator, Expected)
    if Field in ("size", "modified", "accessed", "created"):
        if Item.Stat is None:
            return False
        try:
            if Field == "size":
                return _CompareNumbers(Item.Stat.st_size, Operator, _ParseSize(Expected))
            Times = {"modified": Item.Stat.st_mtime, "accessed": Item.Stat.st_atime, "created": Item.Stat.st_ctime}
            return _CompareNumbers(Times[Field], Operator, datetime.fromisoformat(Expected).timestamp())
        except ValueError:
            return False

    TagName = FieldName[4:] if Field.startswith("tag.") else FieldName
    if Item.Book is None:
        return False
    Raw = next((Value for Key, Value in Item.Book.Tags.items() if Key.casefold() == TagName.casefold()), None)
    if Raw is None:
        return False
    if Raw == Unset or isinstance(Raw, str):
        return _CompareText(str(Raw), Operator, Expected)
    if isinstance(Raw, bool):
        Wanted = _ParseBoolean(Expected)
        return Wanted is not None and Operator in ("=", "!=") and (Raw == Wanted) == (Operator == "=")
    if isinstance(Raw, (int, float)):
        try:
            return _CompareNumbers(float(Raw), Operator, float(Expected))
        except ValueError:
            return _CompareText(str(Raw), Operator, Expected)
    return _CompareText(FormatValue(Raw), Operator, Expected)


# Sort

def CriterionLabel(Criterion: str) -> str:
    return f"Tag: {Criterion[4:]}" if Criterion.startswith("Tag:") else SortNames.get(Criterion, Criterion)


def _CriterionValue(Item: Entry, Criterion: str) -> tuple[bool, Any]:
    """(missing, comparable value)."""
    Stat = Item.Stat
    if Criterion == "Name":
        return False, NaturalKey(Item.Path.name)
    if Criterion in ("Modified", "Accessed", "Created", "FileSize"):
        if Stat is None:
            return True, 0
        return False, {"Modified": Stat.st_mtime, "Accessed": Stat.st_atime, "Created": Stat.st_ctime,
                       "FileSize": Stat.st_size}[Criterion]
    if Criterion == "FileType":
        return False, NaturalKey("" if Item.IsDirectory else Item.Path.suffix.lstrip("."))
    if Criterion == "Record":
        return not Item.RecordName, NaturalKey(Item.RecordName)
    if Criterion.startswith("Tag:"):
        TagName = Criterion[4:]
        Value = Item.TagValue(TagName)
        if Value is None:
            return True, 0
        Definition = Item.TagDefinition(TagName)
        Kind = TagType(Definition)
        if Kind == "Boolean":
            return False, int(bool(Value))
        if Kind in ("Number", "Rating"):
            try:
                return False, float(Value)
            except (TypeError, ValueError):
                return True, 0
        if Kind == "List" and isinstance(Definition.get("Values"), list):
            Values = Definition["Values"]
            return False, Values.index(Value) if Value in Values else len(Values)
        return False, NaturalKey(str(Value))
    return False, NaturalKey(Item.Path.name)


def _Compare(Left: Any, Right: Any) -> int:
    try:
        return (Left > Right) - (Left < Right)
    except TypeError:
        return _Compare(str(Left), str(Right))


def SortEntries(Items: list[Entry], Criteria: list[str], Descending: bool) -> list[Entry]:
    Direction = -1 if Descending else 1

    def Compare(Left: Entry, Right: Entry) -> int:
        for Criterion in Criteria:
            LeftMissing, LeftValue = _CriterionValue(Left, Criterion)
            RightMissing, RightValue = _CriterionValue(Right, Criterion)
            if LeftMissing != RightMissing:
                return 1 if LeftMissing else -1  # missing values last, either direction
            if not LeftMissing and (Result := _Compare(LeftValue, RightValue)):
                return Result * Direction
        return _Compare(NaturalKey(Left.Path.name), NaturalKey(Right.Path.name)) * Direction

    Key = cmp_to_key(Compare)
    return sorted((Item for Item in Items if Item.IsDirectory), key=Key) + sorted((Item for Item in Items if not Item.IsDirectory), key=Key)