use miette::{Result, IntoDiagnostic, Context};
use std::fs;
use regex::Regex;
use tracing::{info, debug};

use crate::sal::traits::{PlatformSal, EnvironmentCtx};
use crate::sal::dell_xps_9380::DellXps9380Sal;
use crate::sal::generic_linux::GenericLinuxSal;
use crate::sal::heuristic::schema::HardwareDb;
use crate::sal::heuristic::discovery::{discover_facts, SystemFactSheet};

pub struct HeuristicEngine;

impl HeuristicEngine {
    /// Loads the hardware database, probes the system, and builds the appropriate SAL.
    pub fn detect_and_build(ctx: EnvironmentCtx) -> Result<(Box<dyn PlatformSal>, SystemFactSheet)> {
        // 1. Load Hardware DB
        let db_path = "assets/hardware_db.toml";
        let db_content = fs::read_to_string(db_path)
            .into_diagnostic()
            .with_context(|| format!("Failed to read hardware database at {}", db_path))?;
        let db: HardwareDb = toml::from_str(&db_content)
            .into_diagnostic()
            .context("Failed to parse hardware_db.toml")?;

        // 2. Discover Facts
        let facts = discover_facts(&ctx.sysfs_base, ctx.runner.as_ref(), &db.discovery, &db.conflicts, db.benchmarking.clone());
        info!("System Identity: {} {}", facts.vendor, facts.model);

        // 3. Routing Logic
        
        // --- Special Case: Dell XPS 13 9380 ---
        if is_match(&facts.vendor, "(?i)Dell.*") && is_match(&facts.model, "(?i)XPS.*13.*9380.*") {
            info!("Specialized SAL Match Found: Dell XPS 13 9380");
            let sal = DellXps9380Sal::init(ctx, facts.clone()).map_err(|e| miette::miette!(e))?;
            return Ok((Box::new(sal), facts));
        }

        // --- Fallback: Generic Linux SAL ---
        debug!("No specialized SAL match. Falling back to GenericLinuxSal with DB quirks.");
        
        // Validation: Ensure we found at least a temperature sensor if required
        if facts.temp_path.is_none() {
            return Err(miette::miette!("No temperature sensor discovered. Generic fallback impossible."));
        }
        if facts.rapl_paths.is_empty() {
            return Err(miette::miette!("No RAPL power interface discovered. Generic fallback impossible."));
        }

        Ok((Box::new(GenericLinuxSal::new(ctx, facts.clone(), db)), facts))
    }
}

fn is_match(input: &str, pattern: &str) -> bool {
    if let Ok(re) = Regex::new(pattern) {
        re.is_match(input)
    } else {
        false
    }
}