//! Shared helpers for the `entropyk-solver` Phase-0 integration tests.
//!
//! Provides the three reference emergent-pressure R134a cycles used as the
//! Phase-0 golden safety net. The construction mirrors `benches/common.rs`
//! so benchmarks and regression tests stay aligned.

use std::sync::Arc;

use entropyk_components::{Condenser, Evaporator, IsenthalpicExpansionValve, IsentropicCompressor};
use entropyk_fluids::{CoolPropBackend, FluidBackend};
use entropyk_solver::system::System;
use entropyk_solver::{ConvergedState, FallbackConfig, FallbackSolver, NewtonConfig, Solver};

fn coolprop_backend() -> Arc<dyn FluidBackend> {
    Arc::new(CoolPropBackend::new())
}

fn build_emergent_cycle(
    cond_sec_temp_k: f64,
    evap_sec_temp_k: f64,
    ua_cond: f64,
    ua_evap: f64,
) -> System {
    use entropyk_components::isentropic_compressor::VolumetricEfficiency;

    let backend = coolprop_backend();
    let fluid = "R134a";

    let comp = Box::new(
        IsentropicCompressor::new(0.70, 318.15, 278.15, 5.0)
            .with_refrigerant(fluid)
            .with_fluid_backend(backend.clone())
            .with_displacement(6.5e-5, 50.0, VolumetricEfficiency::Constant(0.92)),
    );

    let cond = Box::new(
        Condenser::new(ua_cond)
            .with_refrigerant(fluid)
            .with_fluid_backend(backend.clone())
            .with_secondary_stream(cond_sec_temp_k, 1500.0)
            .with_emergent_pressure(5.0),
    );

    let exv = Box::new(
        IsenthalpicExpansionValve::new(278.15)
            .with_refrigerant(fluid)
            .with_fluid_backend(backend.clone())
            .with_emergent_pressure(),
    );

    let evap = Box::new(
        Evaporator::new(ua_evap)
            .with_refrigerant(fluid)
            .with_fluid_backend(backend.clone())
            .with_secondary_stream(evap_sec_temp_k, 2000.0)
            .with_emergent_pressure(),
    );

    let mut system = System::new();
    let n_comp = system.add_component(comp);
    let n_cond = system.add_component(cond);
    let n_exv = system.add_component(exv);
    let n_evap = system.add_component(evap);

    system.add_edge(n_comp, n_cond).unwrap();
    system.add_edge(n_cond, n_exv).unwrap();
    system.add_edge(n_exv, n_evap).unwrap();
    system.add_edge(n_evap, n_comp).unwrap();

    system.finalize().unwrap();
    system
}

pub fn build_reference_cycle_a() -> System {
    build_emergent_cycle(303.15, 285.15, 766.0, 1468.0)
}

pub fn build_reference_cycle_b() -> System {
    build_emergent_cycle(313.15, 283.15, 900.0, 1600.0)
}

pub fn build_reference_cycle_c() -> System {
    build_emergent_cycle(308.15, 291.15, 850.0, 1800.0)
}

fn newton_config_for_reference() -> NewtonConfig {
    let initial_state = vec![
        0.05,   // shared mass flow [kg/s]
        11.6e5, // comp->cond pressure [Pa]
        445e3,  // comp->cond enthalpy [J/kg]
        11.6e5, // cond->exv pressure [Pa]
        262e3,  // cond->exv enthalpy [J/kg]
        3.5e5,  // exv->evap pressure [Pa]
        262e3,  // exv->evap enthalpy [J/kg]
        3.5e5,  // evap->comp pressure [Pa]
        405e3,  // evap->comp enthalpy [J/kg]
    ];
    NewtonConfig {
        max_iterations: 200,
        tolerance: 1e-6,
        initial_state: Some(initial_state),
        ..NewtonConfig::default()
    }
}

/// Solves a reference cycle and returns the converged state vector.
pub fn solve_reference_system_with_state(system: &mut System) -> ConvergedState {
    let newton = newton_config_for_reference();
    let mut solver = FallbackSolver::new(FallbackConfig::default()).with_newton_config(newton);
    solver.solve(system).expect("reference cycle must converge")
}