//! Trait modifier system for unprompted disclosure (#173, D-081).
//!
//! Two-stage filter: Stage 1 (WHAT) modifies the disclosure candidate pool,
//! Stage 2 (HOW) weights line selection via delivery tags.
//!
//! Traits map to filter predicates via content-authorable YAML config —
//! not hard-coded enum dispatch. Content authors define what each trait
//! does to the candidate pool and which delivery tags it prefers.

use std::collections::BTreeMap;

use bevy_ecs::prelude::*;
use serde::Deserialize;

use crate::knowledge::types::{FactKnowledge, KnowledgeConfidence, KnowledgeSource};

// ---------------------------------------------------------------------------
// YAML-authored trait modifier config
// ---------------------------------------------------------------------------

/// Full trait modifier configuration resource. Loaded from YAML.
///
/// Keys are trait names (lowercase, matching `PersonalityTrait` string
/// representation): `"cautious"`, `"gossipy"`, `"loyal"`, `"talkative"`, etc.
///
/// BTreeMap for deterministic iteration (D-010 principle 4).
#[derive(Resource, Debug, Clone, Default, Deserialize)]
pub struct TraitModifierConfig {
    /// Trait name → modifier rules. Trait names are lowercase_snake_case.
    #[serde(default)]
    pub modifiers: BTreeMap<String, TraitModifier>,
}

/// A single trait's filter and scoring rules.
#[derive(Debug, Clone, Default, Deserialize)]
pub struct TraitModifier {
    /// Stage 1: candidate pool filter (WHAT gets disclosed).
    #[serde(default)]
    pub stage1: Stage1Filter,
    /// Stage 2: line pool scoring (HOW it's delivered).
    #[serde(default)]
    pub stage2: Stage2Scoring,
}

/// Stage 1 filter predicates — modify the disclosure candidate pool.
///
/// Applied per-fact during candidate selection in `DisclosureCandidates`
/// (#551). Multiple traits compose additively: if any trait includes a
/// candidate that would otherwise be excluded, it's included.
///
/// Default values (all false/None) produce no modification to the
/// baseline filter, which requires KnowsOf minimum confidence and
/// includes all source types.
#[derive(Debug, Clone, Default, Deserialize)]
pub struct Stage1Filter {
    /// Minimum confidence to enter the disclosure pool.
    /// Parsed at load time: "suspects", "knows_of", "knows_details", "direct".
    /// None = use system default (KnowsOf).
    #[serde(default)]
    pub min_confidence: Option<String>,
    /// If true, exclude facts with `ToldBy` source (won't pass on rumors).
    /// Cautious trait behavior.
    #[serde(default)]
    pub exclude_told_by: bool,
    /// If true, exclude facts linked to entities with trust_level >= Real
    /// in NPC Relationships. Loyal trait behavior.
    #[serde(default)]
    pub exclude_high_trust_entities: bool,
    /// If true, override the witness inhibition gate. Talkative trait behavior.
    #[serde(default)]
    pub override_witness_inhibition: bool,
}

/// Stage 2 scoring — influence line selection weighting.
///
/// Delivery tags in `IndexedDialogueLine.tags` are matched against
/// the NPC's trait-derived preferred tags. Lines with matching tags
/// receive a scoring bonus during Layer 4 selection.
#[derive(Debug, Clone, Default, Deserialize)]
pub struct Stage2Scoring {
    /// Preferred delivery tags for line selection weighting.
    /// Examples: `["cautious_delivery"]`, `["gossip_delivery", "casual_delivery"]`.
    /// Lines with matching tags receive a scoring bonus.
    #[serde(default)]
    pub delivery_tags: Vec<String>,
}

// ---------------------------------------------------------------------------
// Filter predicate evaluation
// ---------------------------------------------------------------------------

impl Stage1Filter {
    /// Parse the min_confidence string into a `KnowledgeConfidence` value.
    /// Returns `None` (use system default) for unparseable or absent values.
    pub fn min_confidence_level(&self) -> Option<KnowledgeConfidence> {
        self.min_confidence.as_deref().and_then(parse_confidence)
    }

    /// Evaluate whether a fact passes this trait's Stage 1 filter.
    ///
    /// Returns `false` if the fact should be excluded by this trait.
    /// The caller (#551) composes multiple trait filters: a fact is
    /// included if it passes the composite filter.
    pub fn allows_fact(&self, fact: &FactKnowledge) -> bool {
        // Check minimum confidence
        if let Some(min) = self.min_confidence_level() {
            if fact.confidence < min {
                return false;
            }
        }

        // Exclude ToldBy-source facts (Cautious behavior)
        if self.exclude_told_by && matches!(fact.source, KnowledgeSource::ToldBy { .. }) {
            return false;
        }

        true
    }
}

impl Stage2Scoring {
    /// Check if a line's tags contain any of this trait's preferred delivery tags.
    /// Returns the number of matching tags (0 = no bonus).
    pub fn tag_match_count(&self, line_tags: &[String]) -> usize {
        self.delivery_tags
            .iter()
            .filter(|dt| line_tags.contains(dt))
            .count()
    }

    /// Check if a line has at least one matching delivery tag.
    pub fn has_matching_tag(&self, line_tags: &[String]) -> bool {
        self.tag_match_count(line_tags) > 0
    }
}

impl TraitModifierConfig {
    /// Look up the modifier for a trait by name.
    pub fn modifier_for(&self, trait_name: &str) -> Option<&TraitModifier> {
        self.modifiers.get(trait_name)
    }

    /// Collect all Stage 2 delivery tags for a set of trait names.
    /// Returns a deduplicated, sorted list for deterministic matching.
    pub fn delivery_tags_for(&self, trait_names: &[String]) -> Vec<String> {
        let mut tags: Vec<String> = trait_names
            .iter()
            .filter_map(|name| self.modifiers.get(name.as_str()))
            .flat_map(|m| m.stage2.delivery_tags.iter().cloned())
            .collect();
        tags.sort();
        tags.dedup();
        tags
    }

    /// Check if any trait in the set overrides witness inhibition.
    pub fn any_overrides_witness_inhibition(&self, trait_names: &[String]) -> bool {
        trait_names.iter().any(|name| {
            self.modifiers
                .get(name.as_str())
                .is_some_and(|m| m.stage1.override_witness_inhibition)
        })
    }

    /// Check if any trait in the set excludes high-trust entity facts.
    pub fn any_excludes_high_trust(&self, trait_names: &[String]) -> bool {
        trait_names.iter().any(|name| {
            self.modifiers
                .get(name.as_str())
                .is_some_and(|m| m.stage1.exclude_high_trust_entities)
        })
    }

    /// Get the most permissive (lowest) min_confidence across all traits.
    /// Returns None if no traits specify a minimum (use system default).
    pub fn lowest_min_confidence(&self, trait_names: &[String]) -> Option<KnowledgeConfidence> {
        trait_names
            .iter()
            .filter_map(|name| self.modifiers.get(name.as_str()))
            .filter_map(|m| m.stage1.min_confidence_level())
            .min()
    }
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

/// Parse a confidence string from YAML config to enum value.
/// Delegates to `KnowledgeConfidence::try_from` (which accepts both
/// camelCase and underscore forms) rather than duplicating the match.
fn parse_confidence(s: &str) -> Option<KnowledgeConfidence> {
    KnowledgeConfidence::try_from(s)
        .map_err(|e| {
            tracing::warn!("Unknown confidence level in trait config: {}", e);
        })
        .ok()
}

/// Convert a `PersonalityTrait` to its lowercase YAML key.
/// Used to look up trait modifiers from the config.
pub fn trait_to_key(trait_val: &super::PersonalityTrait) -> &'static str {
    match trait_val {
        super::PersonalityTrait::Cautious => "cautious",
        super::PersonalityTrait::Bold => "bold",
        super::PersonalityTrait::Honest => "honest",
        super::PersonalityTrait::Deceptive => "deceptive",
        super::PersonalityTrait::Compassionate => "compassionate",
        super::PersonalityTrait::Ruthless => "ruthless",
        super::PersonalityTrait::Curious => "curious",
        super::PersonalityTrait::Incurious => "incurious",
        super::PersonalityTrait::Social => "social",
        super::PersonalityTrait::Reclusive => "reclusive",
    }
}

/// Convert an NPC's personality trait list to YAML config keys.
pub fn traits_to_keys(traits: &[super::PersonalityTrait]) -> Vec<String> {
    traits.iter().map(|t| trait_to_key(t).to_string()).collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    fn make_fact(confidence: KnowledgeConfidence, source: KnowledgeSource) -> FactKnowledge {
        FactKnowledge {
            confidence,
            source,
            state: crate::knowledge::types::KnowledgeState::Active,
            acquired_tick: 100,
            disclosure_blocked: false,
        }
    }

    fn cautious_config() -> TraitModifierConfig {
        let yaml = r#"
modifiers:
  cautious:
    stage1:
      min_confidence: "knows_details"
      exclude_told_by: true
    stage2:
      delivery_tags: ["cautious_delivery"]
  gossipy:
    stage1:
      min_confidence: "suspects"
    stage2:
      delivery_tags: ["gossip_delivery", "casual_delivery"]
  loyal:
    stage1:
      exclude_high_trust_entities: true
    stage2:
      delivery_tags: ["professional_delivery"]
  talkative:
    stage1:
      override_witness_inhibition: true
      min_confidence: "suspects"
    stage2:
      delivery_tags: ["casual_delivery", "gossip_delivery"]
"#;
        serde_yaml::from_str(yaml).expect("valid trait config YAML")
    }

    #[test]
    fn parse_config_from_yaml() {
        let config = cautious_config();
        assert_eq!(config.modifiers.len(), 4);
        assert!(config.modifiers.contains_key("cautious"));
        assert!(config.modifiers.contains_key("gossipy"));
        assert!(config.modifiers.contains_key("loyal"));
        assert!(config.modifiers.contains_key("talkative"));
    }

    #[test]
    fn cautious_excludes_low_confidence() {
        let config = cautious_config();
        let cautious = &config.modifiers["cautious"].stage1;

        let suspects_fact = make_fact(
            KnowledgeConfidence::Suspects,
            KnowledgeSource::DirectObservation { tick: 50 },
        );
        let details_fact = make_fact(
            KnowledgeConfidence::KnowsDetails,
            KnowledgeSource::DirectObservation { tick: 50 },
        );

        assert!(
            !cautious.allows_fact(&suspects_fact),
            "Cautious excludes Suspects"
        );
        assert!(
            cautious.allows_fact(&details_fact),
            "Cautious allows KnowsDetails"
        );
    }

    #[test]
    fn cautious_excludes_told_by() {
        let config = cautious_config();
        let cautious = &config.modifiers["cautious"].stage1;

        let told_fact = make_fact(
            KnowledgeConfidence::KnowsDetails,
            KnowledgeSource::ToldBy {
                source_id: crate::knowledge::types::StableId(42),
                tick: 50,
            },
        );
        assert!(
            !cautious.allows_fact(&told_fact),
            "Cautious excludes ToldBy"
        );
    }

    #[test]
    fn gossipy_includes_suspects() {
        let config = cautious_config();
        let gossipy = &config.modifiers["gossipy"].stage1;

        let suspects_fact = make_fact(
            KnowledgeConfidence::Suspects,
            KnowledgeSource::DirectObservation { tick: 50 },
        );
        assert!(
            gossipy.allows_fact(&suspects_fact),
            "Gossipy includes Suspects"
        );
    }

    #[test]
    fn talkative_overrides_witness_inhibition() {
        let config = cautious_config();
        let traits = vec!["talkative".to_string()];
        assert!(config.any_overrides_witness_inhibition(&traits));

        let traits = vec!["cautious".to_string()];
        assert!(!config.any_overrides_witness_inhibition(&traits));
    }

    #[test]
    fn loyal_excludes_high_trust() {
        let config = cautious_config();
        let traits = vec!["loyal".to_string()];
        assert!(config.any_excludes_high_trust(&traits));

        let traits = vec!["gossipy".to_string()];
        assert!(!config.any_excludes_high_trust(&traits));
    }

    #[test]
    fn lowest_min_confidence_picks_most_permissive() {
        let config = cautious_config();
        // Gossipy (suspects) + Cautious (knows_details) → suspects wins
        let traits = vec!["gossipy".to_string(), "cautious".to_string()];
        assert_eq!(
            config.lowest_min_confidence(&traits),
            Some(KnowledgeConfidence::Suspects)
        );
    }

    #[test]
    fn delivery_tags_deduped_and_sorted() {
        let config = cautious_config();
        // Gossipy + Talkative both have "casual_delivery" and "gossip_delivery"
        let traits = vec!["gossipy".to_string(), "talkative".to_string()];
        let tags = config.delivery_tags_for(&traits);
        assert_eq!(tags, vec!["casual_delivery", "gossip_delivery"]);
    }

    #[test]
    fn stage2_tag_matching() {
        let config = cautious_config();
        let scoring = &config.modifiers["cautious"].stage2;

        let line_tags = vec!["cautious_delivery".to_string(), "observation".to_string()];
        assert!(scoring.has_matching_tag(&line_tags));
        assert_eq!(scoring.tag_match_count(&line_tags), 1);

        let no_match_tags = vec!["gossip_delivery".to_string()];
        assert!(!scoring.has_matching_tag(&no_match_tags));
    }

    #[test]
    fn unknown_trait_returns_none() {
        let config = cautious_config();
        assert!(config.modifier_for("unknown_trait").is_none());
    }

    #[test]
    fn trait_to_key_roundtrip() {
        use super::super::PersonalityTrait;
        assert_eq!(trait_to_key(&PersonalityTrait::Cautious), "cautious");
        assert_eq!(trait_to_key(&PersonalityTrait::Bold), "bold");
        assert_eq!(trait_to_key(&PersonalityTrait::Social), "social");
    }

    #[test]
    fn traits_to_keys_conversion() {
        use super::super::PersonalityTrait;
        let traits = vec![PersonalityTrait::Cautious, PersonalityTrait::Social];
        let keys = traits_to_keys(&traits);
        assert_eq!(keys, vec!["cautious", "social"]);
    }

    #[test]
    fn empty_config_is_no_op() {
        let config = TraitModifierConfig::default();
        let traits = vec!["cautious".to_string()];
        assert!(!config.any_overrides_witness_inhibition(&traits));
        assert!(!config.any_excludes_high_trust(&traits));
        assert_eq!(config.lowest_min_confidence(&traits), None);
        assert!(config.delivery_tags_for(&traits).is_empty());
    }

    #[test]
    fn default_filter_allows_everything() {
        let filter = Stage1Filter::default();
        let fact = make_fact(
            KnowledgeConfidence::Suspects,
            KnowledgeSource::ToldBy {
                source_id: crate::knowledge::types::StableId(1),
                tick: 10,
            },
        );
        assert!(filter.allows_fact(&fact), "Default filter allows all facts");
    }

    #[test]
    fn parse_confidence_values() {
        assert_eq!(
            parse_confidence("suspects"),
            Some(KnowledgeConfidence::Suspects)
        );
        assert_eq!(
            parse_confidence("knows_of"),
            Some(KnowledgeConfidence::KnowsOf)
        );
        assert_eq!(
            parse_confidence("knows_details"),
            Some(KnowledgeConfidence::KnowsDetails)
        );
        assert_eq!(
            parse_confidence("direct"),
            Some(KnowledgeConfidence::Direct)
        );
        assert_eq!(parse_confidence("invalid"), None);
    }

    // --- Coverage gap closure tests ---

    #[test]
    fn cautious_excludes_knows_of_below_threshold() {
        // Cautious min_confidence is "knows_details". KnowsOf < KnowsDetails,
        // so a KnowsOf fact must be excluded (not just Suspects).
        let config = cautious_config();
        let cautious = &config.modifiers["cautious"].stage1;

        let knows_of_fact = make_fact(
            KnowledgeConfidence::KnowsOf,
            KnowledgeSource::DirectObservation { tick: 50 },
        );
        assert!(
            !cautious.allows_fact(&knows_of_fact),
            "Cautious should exclude KnowsOf (below knows_details threshold)"
        );
    }

    #[test]
    fn cautious_allows_direct_confidence() {
        // Direct > KnowsDetails, so Direct passes cautious min_confidence.
        let config = cautious_config();
        let cautious = &config.modifiers["cautious"].stage1;

        let direct_fact = make_fact(
            KnowledgeConfidence::Direct,
            KnowledgeSource::DirectObservation { tick: 50 },
        );
        assert!(
            cautious.allows_fact(&direct_fact),
            "Cautious should allow Direct confidence (above threshold)"
        );
    }

    #[test]
    fn gossipy_allows_all_confidence_levels() {
        // Gossipy min_confidence is "suspects" — all confidence levels pass.
        let config = cautious_config();
        let gossipy = &config.modifiers["gossipy"].stage1;

        for (confidence, label) in [
            (KnowledgeConfidence::Suspects, "Suspects"),
            (KnowledgeConfidence::KnowsOf, "KnowsOf"),
            (KnowledgeConfidence::KnowsDetails, "KnowsDetails"),
            (KnowledgeConfidence::Direct, "Direct"),
        ] {
            let fact = make_fact(confidence, KnowledgeSource::DirectObservation { tick: 50 });
            assert!(
                gossipy.allows_fact(&fact),
                "Gossipy should allow {} confidence",
                label
            );
        }
    }

    #[test]
    fn all_personality_traits_map_to_unique_keys() {
        use super::super::PersonalityTrait;

        let all_traits = vec![
            PersonalityTrait::Cautious,
            PersonalityTrait::Bold,
            PersonalityTrait::Honest,
            PersonalityTrait::Deceptive,
            PersonalityTrait::Compassionate,
            PersonalityTrait::Ruthless,
            PersonalityTrait::Curious,
            PersonalityTrait::Incurious,
            PersonalityTrait::Social,
            PersonalityTrait::Reclusive,
        ];

        let keys: Vec<&str> = all_traits.iter().map(|t| trait_to_key(t)).collect();

        // All 10 traits produce a non-empty key
        for (trait_, key) in all_traits.iter().zip(keys.iter()) {
            assert!(!key.is_empty(), "{:?} must map to a non-empty key", trait_);
        }

        // All keys are unique (no two traits share a key)
        let mut sorted = keys.clone();
        sorted.sort_unstable();
        sorted.dedup();
        assert_eq!(
            sorted.len(),
            all_traits.len(),
            "All personality traits must map to distinct keys"
        );
    }

    #[test]
    fn stage2_multiple_tag_matches_counts_correctly() {
        // When a line has two matching delivery tags, tag_match_count returns 2.
        let config = cautious_config();
        // Talkative has: ["casual_delivery", "gossip_delivery"]
        let talkative_scoring = &config.modifiers["talkative"].stage2;

        let line_tags = vec![
            "casual_delivery".to_string(),
            "gossip_delivery".to_string(),
            "unrelated_tag".to_string(),
        ];
        assert_eq!(
            talkative_scoring.tag_match_count(&line_tags),
            2,
            "Both delivery tags should match"
        );
        assert!(talkative_scoring.has_matching_tag(&line_tags));
    }

    #[test]
    fn gossipy_does_not_exclude_told_by() {
        // Gossipy has no exclude_told_by restriction — it should pass ToldBy facts.
        let config = cautious_config();
        let gossipy = &config.modifiers["gossipy"].stage1;

        let told_fact = make_fact(
            KnowledgeConfidence::Suspects,
            KnowledgeSource::ToldBy {
                source_id: crate::knowledge::types::StableId(5),
                tick: 10,
            },
        );
        assert!(
            gossipy.allows_fact(&told_fact),
            "Gossipy should not exclude ToldBy-source facts"
        );
    }
}