use super::harness::*;
use std::collections::HashMap;

fn parse_params(output: &str) -> HashMap<String, f64> {
    let mut params = HashMap::new();
    let parts: Vec<&str> = output.trim_start_matches('/').split('/').collect();
    let mut i = 0;
    while i + 1 < parts.len() {
        if let Ok(v) = parts[i + 1].parse::<f64>() {
            params.insert(parts[i].to_string(), v);
        }
        i += 2;
    }
    params
}

fn get_deltas(outputs: &[String]) -> Vec<f64> {
    outputs
        .iter()
        .map(|o| parse_params(o).get("delta").copied().unwrap_or(0.0))
        .collect()
}

fn get_durs(outputs: &[String]) -> Vec<f64> {
    outputs
        .iter()
        .map(|o| parse_params(o).get("dur").copied().unwrap_or(0.0))
        .collect()
}

fn get_sounds(outputs: &[String]) -> Vec<String> {
    outputs
        .iter()
        .map(|o| {
            let parts: Vec<&str> = o.trim_start_matches('/').split('/').collect();
            if parts.len() >= 2 && parts[0] == "sound" {
                parts[1].to_string()
            } else {
                String::new()
            }
        })
        .collect()
}

const EPSILON: f64 = 1e-9;

fn approx_eq(a: f64, b: f64) -> bool {
    (a - b).abs() < EPSILON
}

#[test]
fn stepdur_baseline() {
    let f = run("stepdur");
    assert!(approx_eq(stack_float(&f), 0.125));
}

#[test]
fn single_emit() {
    let outputs = expect_outputs(r#""kick" s ."#, 1);
    let deltas = get_deltas(&outputs);
    assert!(approx_eq(deltas[0], 0.0), "single emit at start should have delta 0");
}

#[test]
fn multiple_emits_all_at_zero() {
    let outputs = expect_outputs(r#""kick" s . . . ."#, 4);
    let deltas = get_deltas(&outputs);
    for (i, delta) in deltas.iter().enumerate() {
        assert!(approx_eq(*delta, 0.0), "emit {}: expected delta 0, got {}", i, delta);
    }
}

#[test]
fn sound_persists() {
    let outputs = expect_outputs(r#""kick" s . . "hat" s . ."#, 4);
    let sounds = get_sounds(&outputs);
    assert_eq!(sounds[0], "kick");
    assert_eq!(sounds[1], "kick");
    assert_eq!(sounds[2], "hat");
    assert_eq!(sounds[3], "hat");
}

#[test]
fn alternating_sounds() {
    let outputs = expect_outputs(r#""kick" s . "snare" s . "kick" s . "snare" s ."#, 4);
    let sounds = get_sounds(&outputs);
    assert_eq!(sounds, vec!["kick", "snare", "kick", "snare"]);
}

#[test]
fn dur_is_step_duration() {
    let outputs = expect_outputs(r#""kick" s ."#, 1);
    let durs = get_durs(&outputs);
    assert!(approx_eq(durs[0], 0.125), "dur should be step_duration (0.125), got {}", durs[0]);
}

#[test]
fn cycle_picks_by_step() {
    for runs in 0..4 {
        let ctx = ctx_with(|c| c.runs = runs);
        let f = forth();
        let outputs = f.evaluate(r#""kick" s < . _ >"#, &ctx).unwrap();
        if runs % 2 == 0 {
            assert_eq!(outputs.len(), 1, "runs={}: . should be picked", runs);
        } else {
            assert_eq!(outputs.len(), 0, "runs={}: _ should be picked", runs);
        }
    }
}

#[test]
fn pcycle_picks_by_pattern() {
    for iter in 0..4 {
        let ctx = ctx_with(|c| c.iter = iter);
        let f = forth();
        let outputs = f.evaluate(r#""kick" s << . _ >>"#, &ctx).unwrap();
        if iter % 2 == 0 {
            assert_eq!(outputs.len(), 1, "iter={}: . should be picked", iter);
        } else {
            assert_eq!(outputs.len(), 0, "iter={}: _ should be picked", iter);
        }
    }
}

#[test]
fn cycle_with_sounds() {
    for runs in 0..3 {
        let ctx = ctx_with(|c| c.runs = runs);
        let f = forth();
        let outputs = f.evaluate(r#"< { "kick" s . } { "hat" s . } { "snare" s . } >"#, &ctx).unwrap();
        assert_eq!(outputs.len(), 1, "runs={}: expected 1 output", runs);
        let sounds = get_sounds(&outputs);
        let expected = ["kick", "hat", "snare"][runs % 3];
        assert_eq!(sounds[0], expected, "runs={}: expected {}", runs, expected);
    }
}

#[test]
fn emit_n_basic() {
    let outputs = expect_outputs(r#""kick" s 4 .!"#, 4);
    let sounds = get_sounds(&outputs);
    assert_eq!(sounds, vec!["kick", "kick", "kick", "kick"]);
}

#[test]
fn emit_n_zero() {
    let outputs = expect_outputs(r#""kick" s 0 .!"#, 0);
    assert!(outputs.is_empty());
}

#[test]
fn emit_n_negative_error() {
    let f = forth();
    let result = f.evaluate(r#""kick" s -1 .!"#, &default_ctx());
    assert!(result.is_err());
}