"""Pydantic models for metric label discovery MCP tools."""

import re
from datetime import datetime
from typing import Optional

from pydantic import BaseModel, Field, field_validator

MAX_LABEL_RESULTS = 100


class ListMetricLabelsRequest(BaseModel):
    """Input model for list_metric_labels requests."""

    cluster_id: str = Field(..., description="Cluster identifier")
    env: str = Field(
        ...,
        description="Environment name used in biz_type resolution (e.g. prod, staging, dev)",
    )
    deploy_type: str = Field(
        ...,
        description=(
            "Cluster deploy type used in biz_type resolution "
            "(dedicated, premium, resource_pool, starter, essential)"
        ),
    )
    match: Optional[str] = Field(
        default=None,
        description=(
            "Optional series selector used as Prometheus match[] filter "
            "(e.g. '{__name__=~\"topsql_.*\"}')."
        ),
    )
    start: Optional[str] = Field(
        default=None,
        description="Optional start timestamp in RFC3339 format.",
    )
    end: Optional[str] = Field(
        default=None,
        description="Optional end timestamp in RFC3339 format.",
    )
    limit: int = Field(
        default=MAX_LABEL_RESULTS,
        ge=1,
        le=MAX_LABEL_RESULTS,
        description=f"Maximum number of labels to return (1–{MAX_LABEL_RESULTS}).",
    )

    @field_validator("match")
    @classmethod
    def normalize_match(cls, v: Optional[str]) -> Optional[str]:
        if v is None or not v.strip():
            return None
        return v.strip()

    @field_validator("start", "end")
    @classmethod
    def validate_timestamp(cls, v: Optional[str]) -> Optional[str]:
        if v is None or not v.strip():
            return None
        value = v.strip()
        try:
            datetime.fromisoformat(value.replace("Z", "+00:00"))
            return value
        except ValueError as e:
            raise ValueError(f"Invalid timestamp format: {value}. Must be RFC3339.") from e

    @field_validator("env", "deploy_type", mode="before")
    @classmethod
    def normalize_scope_text(cls, v: str) -> str:
        return v.strip().lower()

    @field_validator("cluster_id", mode="before")
    @classmethod
    def normalize_cluster_id(cls, v: object) -> str:
        if not isinstance(v, str):
            raise ValueError("cluster_id must be a string. Quote numeric IDs explicitly.")
        return str(v).strip()


class ListMetricLabelValuesRequest(BaseModel):
    """Input model for list_metric_label_values requests."""

    cluster_id: str = Field(..., description="Cluster identifier")
    env: str = Field(
        ...,
        description="Environment name used in biz_type resolution (e.g. prod, staging, dev)",
    )
    deploy_type: str = Field(
        ...,
        description=(
            "Cluster deploy type used in biz_type resolution "
            "(dedicated, premium, resource_pool, starter, essential)"
        ),
    )
    label: str = Field(..., description="Label name (e.g. instance, job, sql_digest)")
    match: Optional[str] = Field(
        default=None,
        description=(
            "Optional series selector used as Prometheus match[] filter (e.g. '{__name__=\"up\"}')."
        ),
    )
    start: Optional[str] = Field(
        default=None,
        description="Optional start timestamp in RFC3339 format.",
    )
    end: Optional[str] = Field(
        default=None,
        description="Optional end timestamp in RFC3339 format.",
    )
    limit: int = Field(
        default=MAX_LABEL_RESULTS,
        ge=1,
        le=MAX_LABEL_RESULTS,
        description=f"Maximum number of values to return (1–{MAX_LABEL_RESULTS}).",
    )

    @field_validator("label")
    @classmethod
    def validate_label(cls, v: str) -> str:
        value = v.strip()
        if not value:
            raise ValueError("label must not be empty")
        if not re.fullmatch(r"[a-zA-Z_][a-zA-Z0-9_]*", value):
            raise ValueError("label must be a valid Prometheus label name")
        return value

    @field_validator("match")
    @classmethod
    def normalize_match(cls, v: Optional[str]) -> Optional[str]:
        if v is None or not v.strip():
            return None
        return v.strip()

    @field_validator("start", "end")
    @classmethod
    def validate_timestamp(cls, v: Optional[str]) -> Optional[str]:
        if v is None or not v.strip():
            return None
        value = v.strip()
        try:
            datetime.fromisoformat(value.replace("Z", "+00:00"))
            return value
        except ValueError as e:
            raise ValueError(f"Invalid timestamp format: {value}. Must be RFC3339.") from e

    @field_validator("env", "deploy_type", mode="before")
    @classmethod
    def normalize_scope_text(cls, v: str) -> str:
        return v.strip().lower()

    @field_validator("cluster_id", mode="before")
    @classmethod
    def normalize_cluster_id(cls, v: object) -> str:
        if not isinstance(v, str):
            raise ValueError("cluster_id must be a string. Quote numeric IDs explicitly.")
        return str(v).strip()