//! 4-layer dialogue selection pipeline (D-028) and monologue trigger evaluation.
//!
//! Layer 1: Access tier filter (hard filter)
//! Layer 2: Situation filter (hard filter)
//! Layer 3: Trust level filter (hard filter)
//! Layer 4: Weighted selection by topic + mood match

use crate::types::{DialogueLine, DialoguePool, MonologueLine, MonologuePool};
use rand::prelude::*;
use rand_chacha::ChaCha20Rng;
use std::path::Path;

// --- Dialogue pipeline ---

pub struct DialogueContext {
    pub access: Vec<String>,
    pub trust: String,
    pub situation: Vec<String>,
    pub topic: Vec<String>,
    pub mood: Vec<String>,
    #[allow(dead_code)]
    pub seed: u64,
}

pub struct DialogueResult {
    pub line_id: String,
    pub text: String,
    pub passed: bool,
    pub weight: f64,
    pub access_pass: bool,
    pub trust_pass: bool,
    pub situation_pass: bool,
    pub topic_match: f64,
    pub mood_match: f64,
    pub access_detail: String,
    pub trust_detail: String,
    pub situation_detail: String,
}

pub fn evaluate_dialogue(pool: &DialoguePool, ctx: &DialogueContext) -> Vec<DialogueResult> {
    pool.lines
        .iter()
        .map(|line| evaluate_dialogue_line(line, ctx))
        .collect()
}

fn evaluate_dialogue_line(line: &DialogueLine, ctx: &DialogueContext) -> DialogueResult {
    // Layer 1: Access tier — at least one of the player's access tiers must match
    let access_pass = line.access.iter().any(|a| ctx.access.contains(a));
    let access_detail = if access_pass {
        let matched: Vec<_> = line
            .access
            .iter()
            .filter(|a| ctx.access.contains(a))
            .collect();
        format!(
            "matched: {}",
            matched
                .iter()
                .map(|s| s.as_str())
                .collect::<Vec<_>>()
                .join(", ")
        )
    } else {
        format!(
            "line requires [{}], player has [{}]",
            line.access.join(", "),
            ctx.access.join(", ")
        )
    };

    // Layer 2: Situation — at least one active situation must match
    let situation_pass = if ctx.situation.is_empty() {
        true // no situation filter = all situations match
    } else {
        line.situation.iter().any(|s| ctx.situation.contains(s))
    };
    let situation_detail = if situation_pass {
        if ctx.situation.is_empty() {
            "no filter applied".to_string()
        } else {
            let matched: Vec<_> = line
                .situation
                .iter()
                .filter(|s| ctx.situation.contains(s))
                .collect();
            format!(
                "matched: {}",
                matched
                    .iter()
                    .map(|s| s.as_str())
                    .collect::<Vec<_>>()
                    .join(", ")
            )
        }
    } else {
        format!(
            "line requires [{}], active: [{}]",
            line.situation.join(", "),
            ctx.situation.join(", ")
        )
    };

    // Layer 3: Trust — line's trust level must be <= player's trust level
    let trust_order = trust_rank(&line.trust);
    let player_trust = trust_rank(&ctx.trust);
    let trust_pass = trust_order <= player_trust;
    let trust_detail = if trust_pass {
        format!("line={} <= player={}", line.trust, ctx.trust)
    } else {
        format!(
            "line requires {} but player only has {}",
            line.trust, ctx.trust
        )
    };

    // Layer 4: Weighted selection by topic + mood overlap
    let topic_match = if ctx.topic.is_empty() || line.topic.is_empty() {
        0.5 // neutral weight when no topic filter
    } else {
        let matches = line.topic.iter().filter(|t| ctx.topic.contains(t)).count();
        if matches > 0 {
            0.5 + 0.5 * (matches as f64 / line.topic.len().max(1) as f64)
        } else {
            0.3 // slight penalty for topic mismatch but not exclusion
        }
    };

    let mood_match = if ctx.mood.is_empty() || line.mood.is_empty() {
        0.5
    } else {
        let matches = line.mood.iter().filter(|m| ctx.mood.contains(m)).count();
        if matches > 0 {
            0.5 + 0.5 * (matches as f64 / line.mood.len().max(1) as f64)
        } else {
            0.3
        }
    };

    let passed = access_pass && situation_pass && trust_pass;
    let weight = if passed {
        topic_match * mood_match
    } else {
        0.0
    };

    DialogueResult {
        line_id: line.id.clone(),
        text: line.text.clone(),
        passed,
        weight,
        access_pass,
        trust_pass,
        situation_pass,
        topic_match,
        mood_match,
        access_detail,
        trust_detail,
        situation_detail,
    }
}

fn trust_rank(trust: &str) -> u8 {
    match trust {
        "surface" => 0,
        "real" => 1,
        "secret" => 2,
        _ => 0,
    }
}

pub fn print_dialogue_results(results: &[DialogueResult], verbose: bool, seed: u64) {
    let passing: Vec<_> = results.iter().filter(|r| r.passed).collect();
    let failing: Vec<_> = results.iter().filter(|r| !r.passed).collect();

    println!(
        "Dialogue evaluation: {} total, {} eligible, {} filtered out\n",
        results.len(),
        passing.len(),
        failing.len()
    );

    for r in &passing {
        println!("  [PASS] {}: {:?}", r.line_id, r.text);
        println!(
            "         weight={:.2}  topic={:.2}  mood={:.2}",
            r.weight, r.topic_match, r.mood_match
        );
        if verbose {
            println!("         access: {}", r.access_detail);
            println!("         trust: {}", r.trust_detail);
            println!("         situation: {}", r.situation_detail);
        }
    }

    if verbose && !failing.is_empty() {
        println!("\n  Filtered out:");
        for r in &failing {
            let reasons: Vec<&str> = [
                if !r.access_pass { Some("access") } else { None },
                if !r.trust_pass { Some("trust") } else { None },
                if !r.situation_pass {
                    Some("situation")
                } else {
                    None
                },
            ]
            .iter()
            .filter_map(|x| *x)
            .collect();

            println!(
                "  [FAIL] {}: {:?}  (failed: {})",
                r.line_id,
                r.text,
                reasons.join(", ")
            );
            if !r.access_pass {
                println!("         access: {}", r.access_detail);
            }
            if !r.trust_pass {
                println!("         trust: {}", r.trust_detail);
            }
            if !r.situation_pass {
                println!("         situation: {}", r.situation_detail);
            }
        }
    }

    // Weighted selection
    if !passing.is_empty() {
        let total_weight: f64 = passing.iter().map(|r| r.weight).sum();
        if total_weight > 0.0 {
            let mut rng = ChaCha20Rng::seed_from_u64(seed);
            let roll: f64 = rng.random::<f64>() * total_weight;
            let mut cumulative = 0.0;
            for r in &passing {
                cumulative += r.weight;
                if cumulative >= roll {
                    println!(
                        "\n  Selected: {} (weight={:.2}/{:.2})",
                        r.line_id, r.weight, total_weight
                    );
                    break;
                }
            }
        }
    } else {
        println!("\n  No eligible lines for this context.");
    }
}

// --- Monologue pipeline ---

pub struct MonologueContext {
    pub trigger: String,
    pub known_facts: Vec<String>,
    #[allow(dead_code)]
    pub seed: u64,
}

pub struct MonologueResult {
    pub line_id: String,
    pub text: String,
    pub passed: bool,
    pub trigger_pass: bool,
    pub prereq_pass: bool,
    pub priority: i32,
    pub trigger_detail: String,
    pub prereq_detail: String,
}

pub fn evaluate_monologue(pool: &MonologuePool, ctx: &MonologueContext) -> Vec<MonologueResult> {
    let mut results: Vec<_> = pool
        .lines
        .iter()
        .map(|line| evaluate_monologue_line(line, ctx))
        .collect();

    // Sort by priority (higher first), then by line_id for determinism
    results.sort_by(|a, b| {
        b.priority
            .cmp(&a.priority)
            .then_with(|| a.line_id.cmp(&b.line_id))
    });

    results
}

fn evaluate_monologue_line(line: &MonologueLine, ctx: &MonologueContext) -> MonologueResult {
    // Trigger match
    let trigger_pass = line.trigger == ctx.trigger;
    let trigger_detail = if trigger_pass {
        format!("matched: {}", ctx.trigger)
    } else {
        format!("line={}, context={}", line.trigger, ctx.trigger)
    };

    // Prerequisite evaluation
    let (prereq_pass, prereq_detail) = if let Some(ref prereqs) = line.prerequisites {
        evaluate_prerequisites(prereqs, &ctx.known_facts)
    } else {
        (true, "no prerequisites".to_string())
    };

    let passed = trigger_pass && prereq_pass;
    let priority = line.priority.unwrap_or(5);

    MonologueResult {
        line_id: line.id.clone(),
        text: line.text.clone(),
        passed,
        trigger_pass,
        prereq_pass,
        priority,
        trigger_detail,
        prereq_detail,
    }
}

fn evaluate_prerequisites(
    prereqs: &crate::types::Prerequisites,
    known_facts: &[String],
) -> (bool, String) {
    let mut details = Vec::new();
    let mut all_pass = true;

    for fact_req in &prereqs.facts {
        let has_fact = known_facts.contains(&fact_req.fact_id);
        if has_fact {
            details.push(format!(
                "fact:{} >= {} [PASS]",
                fact_req.fact_id, fact_req.min_confidence
            ));
        } else {
            details.push(format!(
                "fact:{} >= {} [FAIL: not known]",
                fact_req.fact_id, fact_req.min_confidence
            ));
            all_pass = false;
        }
    }

    // Entity attributes and relationships are not yet checkable without full game state
    if !prereqs.entity_attributes.is_empty() {
        details.push(format!(
            "{} entity_attribute prereqs (skipped: no game state)",
            prereqs.entity_attributes.len()
        ));
    }

    if prereqs.relationship.is_some() {
        details.push("relationship prereq (skipped: no game state)".to_string());
    }

    if details.is_empty() {
        (true, "no prerequisites".to_string())
    } else {
        (all_pass, details.join("; "))
    }
}

pub fn print_monologue_results(results: &[MonologueResult], verbose: bool, _seed: u64) {
    let passing: Vec<_> = results.iter().filter(|r| r.passed).collect();
    let failing: Vec<_> = results.iter().filter(|r| !r.passed).collect();

    println!(
        "Monologue evaluation: {} total, {} eligible, {} filtered out\n",
        results.len(),
        passing.len(),
        failing.len()
    );

    for r in &passing {
        println!(
            "  [PASS] {} (priority={}): {:?}",
            r.line_id, r.priority, r.text
        );
        if verbose {
            println!("         trigger: {}", r.trigger_detail);
            println!("         prereqs: {}", r.prereq_detail);
        }
    }

    if verbose && !failing.is_empty() {
        println!("\n  Filtered out:");
        for r in &failing {
            let reasons: Vec<&str> = [
                if !r.trigger_pass {
                    Some("trigger")
                } else {
                    None
                },
                if !r.prereq_pass {
                    Some("prerequisites")
                } else {
                    None
                },
            ]
            .iter()
            .filter_map(|x| *x)
            .collect();

            println!(
                "  [FAIL] {}: {:?}  (failed: {})",
                r.line_id,
                r.text,
                reasons.join(", ")
            );
            if !r.trigger_pass {
                println!("         trigger: {}", r.trigger_detail);
            }
            if !r.prereq_pass {
                println!("         prereqs: {}", r.prereq_detail);
            }
        }
    }

    // Selection: highest priority eligible line
    if let Some(selected) = passing.first() {
        println!(
            "\n  Selected: {} (priority={})",
            selected.line_id, selected.priority
        );
    } else {
        println!("\n  No eligible lines for this trigger.");
    }
}

// --- Coverage report ---

pub fn print_coverage_report(yaml_str: &str, path: &Path) {
    // Try dialogue first, then monologue
    if let Ok(pool) = serde_yaml::from_str::<DialoguePool>(yaml_str) {
        print_dialogue_coverage(&pool, path);
    } else if let Ok(pool) = serde_yaml::from_str::<MonologuePool>(yaml_str) {
        print_monologue_coverage(&pool, path);
    } else {
        eprintln!("Error: file is neither dialogue nor monologue YAML");
        std::process::exit(1);
    }
}

fn print_dialogue_coverage(pool: &DialoguePool, path: &Path) {
    let access_tiers = ["public", "insider", "authority", "peer", "hostile"];
    let trust_levels = ["surface", "real", "secret"];
    let situations = [
        "arrival",
        "shift_start",
        "shift_end",
        "shift_transition",
        "bar_evening",
        "night_shift",
        "investigation",
        "confrontation",
        "social",
        "alone",
        "emergency",
        "routine",
        "observation",
    ];

    println!(
        "Coverage report: {} (role: {}, location: {})\n",
        path.display(),
        pool.role,
        pool.location
    );

    let mut gaps = Vec::new();

    for access in &access_tiers {
        for trust in &trust_levels {
            for situation in &situations {
                let eligible = pool
                    .lines
                    .iter()
                    .filter(|line| {
                        line.access.iter().any(|a| a == access)
                            && trust_rank(&line.trust) <= trust_rank(trust)
                            && line.situation.iter().any(|s| s == situation)
                    })
                    .count();

                if eligible == 0 {
                    gaps.push(format!(
                        "  access={:<10} trust={:<8} situation={:<18} -> 0 lines",
                        access, trust, situation
                    ));
                }
            }
        }
    }

    if gaps.is_empty() {
        println!("  Full coverage! Every access/trust/situation combination has at least one eligible line.");
    } else {
        println!(
            "  {} gaps found (access/trust/situation combos with zero eligible lines):\n",
            gaps.len()
        );
        // Show first 20 gaps
        for gap in gaps.iter().take(20) {
            println!("{gap}");
        }
        if gaps.len() > 20 {
            println!("  ... and {} more", gaps.len() - 20);
        }
    }

    println!(
        "\n  Total lines: {}, Access tiers used: {:?}, Trust levels used: {:?}",
        pool.lines.len(),
        pool.lines
            .iter()
            .flat_map(|l| l.access.iter())
            .collect::<std::collections::BTreeSet<_>>(),
        pool.lines
            .iter()
            .map(|l| l.trust.as_str())
            .collect::<std::collections::BTreeSet<_>>(),
    );
}

fn print_monologue_coverage(pool: &MonologuePool, path: &Path) {
    let triggers = [
        "enter_location",
        "observe_npc",
        "hear_sound",
        "observe_anomaly",
        "post_conversation",
        "discover_evidence",
        "witness_interaction",
        "time_idle",
        "return_visit",
    ];

    println!(
        "Coverage report: {} (character: {}, location: {})\n",
        path.display(),
        pool.character,
        pool.location
    );

    let mut covered = Vec::new();
    let mut uncovered = Vec::new();

    for trigger in &triggers {
        let count = pool
            .lines
            .iter()
            .filter(|line| line.trigger == *trigger)
            .count();
        if count > 0 {
            covered.push(format!("  {:<25} {} lines", trigger, count));
        } else {
            uncovered.push(format!("  {:<25} 0 lines", trigger));
        }
    }

    if !covered.is_empty() {
        println!("  Covered triggers:");
        for line in &covered {
            println!("{line}");
        }
    }

    if !uncovered.is_empty() {
        println!("\n  Uncovered triggers:");
        for line in &uncovered {
            println!("{line}");
        }
    }

    let with_prereqs = pool
        .lines
        .iter()
        .filter(|l| l.prerequisites.is_some())
        .count();
    println!(
        "\n  Total lines: {}, With prerequisites: {}",
        pool.lines.len(),
        with_prereqs
    );
}