from __future__ import annotations

from dataclasses import dataclass
from typing import TYPE_CHECKING, Any
from urllib.parse import urlparse

from email_validator import EmailNotValidError, validate_email

if TYPE_CHECKING:
    from cli.core.template.variable_section import VariableSection

DEFAULT_AUTOGENERATED_LENGTH = 32
DEFAULT_AUTOGENERATED_BYTES = 32
TRUE_VALUES = {"true", "1", "yes", "on"}
FALSE_VALUES = {"false", "0", "no", "off"}
SECRET_TYPE = "secret"
SECRET_AUTOGENERATED_KIND_CHARACTERS = "characters"
SECRET_AUTOGENERATED_KIND_BASE64 = "base64"


@dataclass
class SecretAutogeneratedConfig:
    """Structured autogeneration settings for secret variables."""

    kind: str = SECRET_AUTOGENERATED_KIND_CHARACTERS
    length: int | None = None
    characters: list[str] | None = None
    bytes: int | None = None

    def clone(self) -> SecretAutogeneratedConfig:
        return SecretAutogeneratedConfig(
            kind=self.kind,
            length=self.length,
            characters=self.characters.copy() if self.characters else None,
            bytes=self.bytes,
        )

    def length_or_default(self) -> int:
        return self.length if self.length is not None else DEFAULT_AUTOGENERATED_LENGTH

    def bytes_or_default(self) -> int:
        return self.bytes if self.bytes is not None else DEFAULT_AUTOGENERATED_BYTES


@dataclass
class VariableConfig:
    """Type-specific variable configuration."""

    placeholder: str | None = None
    textarea: bool = False
    unit: str | None = None
    options: list[str] | None = None
    slider: bool = False
    min: int | None = None
    max: int | None = None
    step: int | None = None
    autogenerated: SecretAutogeneratedConfig | None = None

    def clone(self) -> VariableConfig:
        return VariableConfig(
            placeholder=self.placeholder,
            textarea=self.textarea,
            unit=self.unit,
            options=self.options.copy() if self.options else None,
            slider=self.slider,
            min=self.min,
            max=self.max,
            step=self.step,
            autogenerated=self.autogenerated.clone() if self.autogenerated else None,
        )

    def is_empty(self) -> bool:
        return (
            not self.placeholder
            and not self.textarea
            and not self.unit
            and not self.options
            and not self.slider
            and self.min is None
            and self.max is None
            and self.step is None
            and self.autogenerated is None
        )


class Variable:
    """Represents a single templating variable with lightweight validation."""

    def __init__(self, data: dict[str, Any]) -> None:
        self._validate_input_data(data)
        self._explicit_fields: set[str] = set(data.keys())

        self.name: str = data["name"]
        self.parent_section: VariableSection | None = data.get("parent_section")
        self.description: str | None = data.get("description") or data.get("display", "")
        self.type: str = data.get("type", "str")
        self.prompt: str | None = data.get("prompt")
        self.value: Any = self._resolve_initial_value(data)
        self.origin: str | None = data.get("origin")
        self.extra: str | None = data.get("extra")
        self.required: bool = data.get("required", False)
        self.original_value: Any | None = data.get("original_value")

        self.config = self._normalize_config(self.name, self.type, data.get("config"))
        self._apply_config_state()
        self._validate_secret_defaults(data)
        self.needs = self._parse_needs(data.get("needs"))
        self._validate_initial_value()

    @staticmethod
    def _validate_input_data(data: dict[str, Any]) -> None:
        if not isinstance(data, dict):
            raise ValueError("Variable data must be a dictionary")
        if "name" not in data:
            raise ValueError("Variable data must contain 'name' key")

    def _resolve_initial_value(self, data: dict[str, Any]) -> Any:
        if "value" in data:
            return data.get("value")
        if "default" in data:
            return data.get("default")
        return False if self.type == "bool" else None

    def _apply_config_state(self) -> None:
        self.options: list[str] | None = self.config.options.copy() if self.config.options else None
        self.autogenerated_config: SecretAutogeneratedConfig | None = (
            self.config.autogenerated.clone() if self.config.autogenerated else None
        )
        self.autogenerated: bool = self.autogenerated_config is not None
        self.autogenerated_length: int = (
            self.autogenerated_config.length_or_default() if self.autogenerated_config else DEFAULT_AUTOGENERATED_LENGTH
        )
        self.autogenerated_base64: bool = bool(
            self.autogenerated_config and self.autogenerated_config.kind == SECRET_AUTOGENERATED_KIND_BASE64
        )

    def _validate_secret_defaults(self, data: dict[str, Any]) -> None:
        if self.type == SECRET_TYPE and self.autogenerated and "default" in data:
            raise ValueError(
                f"Invalid default for variable '{self.name}': autogenerated secrets cannot define defaults"
            )

    def _parse_needs(self, needs_value: Any) -> list[str]:
        if not needs_value:
            return []
        if isinstance(needs_value, str):
            return [need.strip() for need in needs_value.split(";") if need.strip()]
        if isinstance(needs_value, list):
            return needs_value
        raise ValueError(f"Variable '{self.name}' has invalid 'needs' value: must be string or list")

    def _validate_initial_value(self) -> None:
        if self.value is None:
            return
        try:
            self.value = self.convert(self.value)
            if self.type == "int" and self.value is not None and self.config.slider:
                self._validate_slider_value(self.value)
        except ValueError as exc:
            raise ValueError(f"Invalid default for variable '{self.name}': {exc}") from exc

    @staticmethod
    def _normalize_str_list(values: list[Any] | None) -> list[str] | None:
        if not values:
            return None

        normalized: list[str] = []
        seen: set[str] = set()
        for value in values:
            item = str(value).strip()
            if not item or item in seen:
                continue
            seen.add(item)
            normalized.append(item)
        return normalized or None

    @classmethod
    def _parse_secret_autogenerated(
        cls,
        variable_name: str,
        autogenerated_input: Any,
        legacy_length: Any = None,
        legacy_base64: bool = False,
    ) -> SecretAutogeneratedConfig | None:
        if autogenerated_input in (None, False):
            return cls._legacy_secret_autogenerated(legacy_length, legacy_base64)

        if autogenerated_input is True:
            return cls._boolean_secret_autogenerated(variable_name, legacy_length, legacy_base64)

        if not isinstance(autogenerated_input, dict):
            raise ValueError("autogenerated must be a boolean or object")

        config = cls._dict_secret_autogenerated(autogenerated_input, legacy_length, legacy_base64)
        return cls._validate_secret_autogenerated(variable_name, config)

    @staticmethod
    def _legacy_secret_autogenerated(
        legacy_length: Any,
        legacy_base64: bool,
    ) -> SecretAutogeneratedConfig | None:
        if not legacy_base64:
            return None
        return SecretAutogeneratedConfig(
            kind=SECRET_AUTOGENERATED_KIND_BASE64,
            bytes=int(legacy_length) if legacy_length is not None else DEFAULT_AUTOGENERATED_BYTES,
        )

    @classmethod
    def _boolean_secret_autogenerated(
        cls,
        variable_name: str,
        legacy_length: Any,
        legacy_base64: bool,
    ) -> SecretAutogeneratedConfig:
        legacy_config = cls._legacy_secret_autogenerated(legacy_length, legacy_base64)
        if legacy_config is not None:
            return legacy_config
        config = SecretAutogeneratedConfig()
        if legacy_length is not None:
            config.length = int(legacy_length)
        return cls._validate_secret_autogenerated(variable_name, config)

    @classmethod
    def _dict_secret_autogenerated(
        cls,
        autogenerated_input: dict[str, Any],
        legacy_length: Any,
        legacy_base64: bool,
    ) -> SecretAutogeneratedConfig:
        kind = str(
            autogenerated_input.get("kind")
            or (SECRET_AUTOGENERATED_KIND_BASE64 if legacy_base64 else SECRET_AUTOGENERATED_KIND_CHARACTERS)
        ).strip()
        config = SecretAutogeneratedConfig(kind=kind)

        if autogenerated_input.get("length") is not None:
            config.length = int(autogenerated_input["length"])
        elif legacy_length is not None and kind != SECRET_AUTOGENERATED_KIND_BASE64:
            config.length = int(legacy_length)

        if autogenerated_input.get("bytes") is not None:
            config.bytes = int(autogenerated_input["bytes"])
        if autogenerated_input.get("characters") is not None:
            config.characters = cls._normalize_secret_characters(autogenerated_input["characters"])
        return config

    @staticmethod
    def _normalize_secret_characters(characters: Any) -> list[str] | None:
        if not isinstance(characters, list):
            raise ValueError("autogenerated.characters must be a list")

        normalized_characters = []
        seen: set[str] = set()
        for char in characters:
            item = str(char).strip()
            if not item:
                continue
            if len(item) != 1:
                raise ValueError("autogenerated.characters entries must each be exactly one character")
            if item in seen:
                continue
            seen.add(item)
            normalized_characters.append(item)
        return normalized_characters or None

    @staticmethod
    def _validate_secret_autogenerated(
        variable_name: str,
        config: SecretAutogeneratedConfig,
    ) -> SecretAutogeneratedConfig:
        kind = (config.kind or SECRET_AUTOGENERATED_KIND_CHARACTERS).strip()
        if kind not in (SECRET_AUTOGENERATED_KIND_CHARACTERS, SECRET_AUTOGENERATED_KIND_BASE64):
            raise ValueError(
                f"variable '{variable_name}' autogenerated.kind must be one of "
                f"'{SECRET_AUTOGENERATED_KIND_CHARACTERS}' or '{SECRET_AUTOGENERATED_KIND_BASE64}'"
            )
        config.kind = kind

        if kind == SECRET_AUTOGENERATED_KIND_CHARACTERS:
            if config.bytes is not None:
                raise ValueError(f"variable '{variable_name}' character autogenerated secrets cannot define bytes")
            if config.length is not None and config.length <= 0:
                raise ValueError(f"variable '{variable_name}' autogenerated.length must be greater than 0")
            if config.characters is not None and not config.characters:
                raise ValueError(f"variable '{variable_name}' autogenerated.characters must not be empty")
            return config

        if config.length is not None:
            raise ValueError(
                f"variable '{variable_name}' base64 autogenerated secrets must use bytes instead of length"
            )
        if config.characters is not None:
            raise ValueError(f"variable '{variable_name}' base64 autogenerated secrets cannot define characters")
        if config.bytes is not None and config.bytes <= 0:
            raise ValueError(f"variable '{variable_name}' autogenerated.bytes must be greater than 0")
        return config

    @classmethod
    def _normalize_config(
        cls,
        variable_name: str,
        variable_type: str,
        config_input: Any,
    ) -> VariableConfig:
        if config_input is None:
            config_data: dict[str, Any] = {}
        elif isinstance(config_input, dict):
            config_data = config_input.copy()
        else:
            raise ValueError(f"Variable '{variable_name}' config must be a dictionary")

        options = cls._normalize_str_list(config_data.get("options"))

        placeholder = config_data.get("placeholder")
        placeholder = str(placeholder).strip() if placeholder not in (None, "") else None
        textarea = bool(config_data.get("textarea", False))
        unit = config_data.get("unit")
        unit = str(unit).strip() if unit not in (None, "") else None
        slider = bool(config_data.get("slider", False))

        min_value = config_data.get("min")
        max_value = config_data.get("max")
        step_value = config_data.get("step")

        min_int = int(min_value) if min_value is not None else None
        max_int = int(max_value) if max_value is not None else None
        step_int = int(step_value) if step_value is not None else None

        autogenerated_input = config_data.get("autogenerated")
        autogenerated_config = None
        if autogenerated_input not in (None, False) and variable_type != SECRET_TYPE:
            raise ValueError("autogenerated is only supported for secret variables")
        if variable_type == SECRET_TYPE:
            autogenerated_config = cls._parse_secret_autogenerated(
                variable_name,
                autogenerated_input,
            )

        config = VariableConfig(
            placeholder=placeholder,
            textarea=textarea,
            unit=unit,
            options=options,
            slider=slider,
            min=min_int,
            max=max_int,
            step=step_int,
            autogenerated=autogenerated_config,
        )

        if variable_type == "enum" and not config.options:
            raise ValueError("enum variables require non-empty options")

        if variable_type == "int" and config.slider:
            if config.min is None or config.max is None:
                raise ValueError("slider variables require min and max")
            if config.max < config.min:
                raise ValueError("slider variables require max >= min")
            if config.step is not None and config.step <= 0:
                raise ValueError("slider variables require step > 0")

        return config

    def is_secret(self) -> bool:
        return self.type == SECRET_TYPE

    def convert(self, value: Any) -> Any:
        if value is None:
            return None

        if isinstance(value, str) and value.strip() == "":
            return None

        converters = {
            "bool": self._convert_bool,
            "int": self._convert_int,
            "float": self._convert_float,
            "enum": self._convert_enum,
            "url": self._convert_url,
            "email": self._convert_email,
        }

        converter = converters.get(self.type)
        if converter:
            return converter(value)

        return str(value)

    def validate_and_convert(self, value: Any, check_required: bool = True) -> Any:
        converted = self.convert(value)

        if self.autogenerated and (converted is None or (isinstance(converted, str) and converted in {"", "*auto"})):
            return None

        if (
            check_required
            and self.is_required()
            and (converted is None or (isinstance(converted, str) and converted == ""))
        ):
            raise ValueError("This field is required and cannot be empty")

        if self.type == "int" and converted is not None and self.config.slider:
            self._validate_slider_value(converted)

        return converted

    def _convert_bool(self, value: Any) -> bool:
        if isinstance(value, bool):
            return value
        if isinstance(value, str):
            lowered = value.strip().lower()
            if lowered in TRUE_VALUES:
                return True
            if lowered in FALSE_VALUES:
                return False
        raise ValueError("value must be a boolean (true/false)")

    def _convert_int(self, value: Any) -> int | None:
        if isinstance(value, bool):
            raise ValueError("value must be an integer")
        if isinstance(value, int):
            return value
        if isinstance(value, str) and value.strip() == "":
            return None
        try:
            return int(value)
        except (TypeError, ValueError) as exc:
            raise ValueError("value must be an integer") from exc

    def _convert_float(self, value: Any) -> float | None:
        if isinstance(value, bool):
            raise ValueError("value must be a float")
        if isinstance(value, (int, float)):
            return float(value)
        if isinstance(value, str) and value.strip() == "":
            return None
        try:
            return float(value)
        except (TypeError, ValueError) as exc:
            raise ValueError("value must be a float") from exc

    def _convert_enum(self, value: Any) -> str | None:
        if value == "":
            return None
        val = str(value)
        if self.options and val not in self.options:
            raise ValueError(f"value must be one of: {', '.join(self.options)}")
        return val

    def _convert_url(self, value: Any) -> str | None:
        val = str(value).strip()
        if not val:
            return None
        parsed = urlparse(val)
        if not (parsed.scheme and parsed.netloc):
            raise ValueError("value must be a valid URL (include scheme and host)")
        return val

    def _convert_email(self, value: Any) -> str | None:
        val = str(value).strip()
        if not val:
            return None
        try:
            validated = validate_email(val, check_deliverability=False)
            return validated.normalized
        except EmailNotValidError as exc:
            raise ValueError(f"value must be a valid email address: {exc}") from exc

    def _validate_slider_value(self, value: int) -> None:
        if not self.config.slider:
            return

        min_value = self.config.min
        max_value = self.config.max
        if min_value is None or max_value is None:
            return

        if value < min_value:
            raise ValueError(f"value must be at least {min_value}")
        if value > max_value:
            raise ValueError(f"value must be at most {max_value}")

        step = self.config.step if self.config.step is not None else 1
        if step > 0 and (value - min_value) % step != 0:
            raise ValueError(f"value must align with step {step} starting at {min_value}")

    def to_dict(self) -> dict[str, Any]:
        result: dict[str, Any] = {}

        if self.type:
            result["type"] = self.type

        if self.value is not None:
            result["default"] = self.value

        for field in ("description", "prompt", "extra", "origin"):
            if value := getattr(self, field):
                result[field] = value

        if self.required:
            result["required"] = True
        config_dict = self._serialize_config()
        if config_dict:
            result["config"] = config_dict

        if self.needs:
            result["needs"] = self.needs[0] if len(self.needs) == 1 else self.needs

        return result

    def _serialize_config(self) -> dict[str, Any]:
        if not self.config or self.config.is_empty():
            return {}

        config_dict: dict[str, Any] = {}
        value_fields = {
            "placeholder": self.config.placeholder,
            "unit": self.config.unit,
            "options": self.config.options,
        }
        for field_name, field_value in value_fields.items():
            if field_value:
                config_dict[field_name] = field_value

        if self.config.textarea:
            config_dict["textarea"] = True
        if self.config.slider:
            config_dict["slider"] = True

        for field_name in ("min", "max", "step"):
            field_value = getattr(self.config, field_name)
            if field_value is not None:
                config_dict[field_name] = field_value

        autogenerated_dict = self._serialize_autogenerated_config()
        if autogenerated_dict is not None:
            config_dict["autogenerated"] = autogenerated_dict

        return config_dict

    def _serialize_autogenerated_config(self) -> bool | dict[str, Any] | None:
        autogenerated = self.config.autogenerated
        if not autogenerated:
            return None
        if self._is_default_character_autogenerated(autogenerated):
            return True

        autogenerated_dict = {"kind": autogenerated.kind}
        for field_name in ("length", "characters", "bytes"):
            field_value = getattr(autogenerated, field_name)
            if field_value is not None:
                autogenerated_dict[field_name] = field_value
        return autogenerated_dict

    @staticmethod
    def _is_default_character_autogenerated(autogenerated: SecretAutogeneratedConfig) -> bool:
        return (
            autogenerated.kind == SECRET_AUTOGENERATED_KIND_CHARACTERS
            and autogenerated.length is None
            and autogenerated.characters is None
            and autogenerated.bytes is None
        )

    def get_display_value(self, mask_secret: bool = True, max_length: int = 30, show_none: bool = True) -> str:
        if self.value is None or self.value == "":
            if self.autogenerated:
                return "[dim](*auto)[/dim]" if show_none else ""
            return "[dim](none)[/dim]" if show_none else ""

        if self.is_secret() and mask_secret:
            return "********"

        display = str(self.value)
        if max_length > 0 and len(display) > max_length:
            return display[: max_length - 3] + "..."
        return display

    def get_normalized_default(self) -> Any:
        typed = self._coerce_default_value()
        if self.autogenerated and not typed:
            return "*auto"
        normalizers = {
            "enum": self._normalize_enum_default,
            "bool": self._normalize_bool_default,
            "int": lambda value: self._normalize_numeric_default(value, int),
            "float": lambda value: self._normalize_numeric_default(value, float),
        }
        normalizer = normalizers.get(self.type, self._normalize_string_default)
        return normalizer(typed)

    def _coerce_default_value(self) -> Any:
        try:
            return self.convert(self.value)
        except Exception:
            return self.value

    def _normalize_enum_default(self, typed: Any) -> Any:
        if not self.options:
            return typed
        if typed is None or str(typed) not in self.options:
            return self.options[0]
        return str(typed)

    @staticmethod
    def _normalize_bool_default(typed: Any) -> bool | None:
        if isinstance(typed, bool):
            return typed
        if typed is None:
            return None
        return bool(typed)

    @staticmethod
    def _normalize_numeric_default(typed: Any, caster) -> Any:
        try:
            return caster(typed) if typed not in (None, "") else None
        except Exception:
            return None

    @staticmethod
    def _normalize_string_default(typed: Any) -> str | None:
        return None if typed is None else str(typed)

    def get_prompt_text(self) -> str:
        prompt_text = self.prompt or self.description or self.name
        if self.value is not None and self.type in ["email", "url"]:
            prompt_text += f" ({self.type})"
        return prompt_text

    def get_validation_hint(self) -> str | None:
        hints = []

        if self.type == "enum" and self.options:
            hints.append(f"Options: {', '.join(self.options)}")

        if self.type == "int" and self.config.slider and self.config.min is not None and self.config.max is not None:
            slider_hint = f"Range: {self.config.min}..{self.config.max}"
            step = self.config.step if self.config.step is not None else 1
            if step != 1:
                slider_hint += f", step {step}"
            if self.config.unit:
                slider_hint += f" {self.config.unit}"
            hints.append(slider_hint)
        elif self.type == "int" and self.config.unit:
            hints.append(f"Unit: {self.config.unit}")

        if self.autogenerated:
            if self.autogenerated_base64:
                bytes_value = (
                    self.autogenerated_config.bytes_or_default()
                    if self.autogenerated_config
                    else DEFAULT_AUTOGENERATED_BYTES
                )
                hints.append(f"Auto-generated base64 secret ({bytes_value} bytes) if empty")
            else:
                length = (
                    self.autogenerated_config.length_or_default()
                    if self.autogenerated_config
                    else DEFAULT_AUTOGENERATED_LENGTH
                )
                hints.append(f"Auto-generated secret (length {length}) if empty")

        if self.extra:
            hints.append(self.extra)

        return " — ".join(hints) if hints else None

    def is_required(self) -> bool:
        return self.required and not self.autogenerated

    def get_parent(self) -> VariableSection | None:
        return self.parent_section

    def clone(self, update: dict[str, Any] | None = None) -> Variable:
        data = {
            "name": self.name,
            "type": self.type,
            "value": self.value,
            "description": self.description,
            "prompt": self.prompt,
            "origin": self.origin,
            "extra": self.extra,
            "required": self.required,
            "original_value": self.original_value,
            "needs": self.needs.copy() if self.needs else None,
            "parent_section": self.parent_section,
            "config": self.config.clone() if self.config else None,
        }

        if update:
            data.update(update)

        cloned = Variable(data)
        cloned._explicit_fields = self._explicit_fields.copy()
        if update:
            cloned._explicit_fields.update(update.keys())
        return cloned