use crate::metric_primitive::MetricPrimitive;
use crate::timestamp::Timestamp;
use serde::{Deserialize, Serialize};
use std::collections::BTreeMap;

/// A single parsed metric primitive extracted from a regex capture group.
#[allow(dead_code)]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RegexToMetricPrimitiveMatcher {
    pub param_name: String,
    pub capture_group: String,
    pub kind: MetricPrimitiveKind,
    /// Ticket 022: whether this param contributes to the bucket's `labels`
    /// (the default) or is the bucket's per-event captured `value` (at most
    /// one `Value`-role param per metric — `declare_metric` rejects more
    /// than one). `#[serde(default)]` so profile files saved before this
    /// field existed still load, with every param defaulting to `Label` —
    /// i.e. unchanged behavior (the fixed occurrence-count-of-1 value).
    #[serde(default)]
    pub role: ParamRole,
}

/// See [`RegexToMetricPrimitiveMatcher::role`].
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
#[serde(rename_all = "lowercase")]
pub enum ParamRole {
    #[default]
    Label,
    Value,
}

/// `rename_all = "lowercase"` matches every other `kind`-style enum exposed
/// over the API/settings JSON (`ColorScheme`, `CssEntryKind`,
/// `ProfileMetricPrimitiveKind`), so `POST /api/params`/`POST /api/metrics`
/// bodies use `"string"`/`"number"`/`"timestamp"`.
#[allow(dead_code)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum MetricPrimitiveKind {
    String,
    Number,
    Timestamp,
    /// Ticket 023: milliseconds. On a metric's `Value`-role param, this
    /// doesn't parse the captured text at all — the value is instead derived
    /// as the elapsed time since the previous counter event with the same
    /// label set (see `crate::engine::apply_metric_to_log`). On any other
    /// param (a `Label`-role metric param, or a standalone `ParamDeclaration`),
    /// it parses the captured text as a literal `i64` millisecond count.
    Duration,
}

/// Value type paired with [`crate::index_key::IndexKey`] in the engine's primary index.
#[allow(dead_code)]
#[derive(Debug, Clone, Serialize)]
pub enum DataValue {
    /// Paired with `IndexKey::IngestedLog`.
    LogLiteral { text: String },
    /// Paired with `IndexKey::ParamDeclaration`.
    ParamDeclaration {
        message_match_regex: String,
        capture_group: String,
        kind: MetricPrimitiveKind,
    },
    /// Paired with `IndexKey::MetricDeclaration`.
    MetricDeclaration {
        message_match_regex: String,
        params: Vec<RegexToMetricPrimitiveMatcher>,
        /// See `crate::engine::DeclareMetricRequest::matched_labels` (ticket 025).
        matched_labels: Option<BTreeMap<String, String>>,
        /// See `crate::engine::DeclareMetricRequest::unmatched_labels` (ticket 025).
        unmatched_labels: Option<BTreeMap<String, String>>,
    },
    /// Paired with `IndexKey::Bucket`.
    BucketValue {
        values: Vec<(u64, Timestamp, MetricPrimitive)>,
    },
    /// Paired with `IndexKey::LastMetricEvent` (ticket 023).
    LastEventTimestamp {
        timestamp: Timestamp,
    },
}