//! am ai — langage naturel → action shell (issues #96 #97).
//!
//! Conversational mode (no `--exec`) spawns AIChat with the prompt and the
//! context files (default: the current directory). Exec mode generates the
//! shell command through aichat (`--code` — never executed by aichat),
//! classifies it, applies the safety policy (settings.shell_ai, dry-run by
//! default) and only executes after confirmation when required.

use crate::app::App;
use crate::cli::AiArgs;
use crate::commands::{require_agent, resolve_exec};
use crate::events::{Event, EventKind};
use crate::shell_ai::{Decision, SafetyMode};
use anyhow::{bail, Context, Result};
use std::process::Command;

pub fn run(app: &App, args: &AiArgs) -> Result<i32> {
    // Onboarding hint (v1.1.0 F1) — non-blocking: the AI commands propose
    // `am setup` when no provider is configured, then continue anyway.
    if crate::setup::needs_setup(app) {
        app.log.info(crate::i18n::tr_in(
            app.lang(),
            "am n'est pas configuré — lancez am setup (provider + token)",
        ));
    }

    // F2 (v1.1.0): aichat must be INSTALLED (not only in the catalog) to
    // power am ai. Offer the installation when missing.
    if !aichat_installed(app) {
        let ask_install = !app.cli.yes
            && app.confirm(crate::i18n::tr_in(
                app.lang(),
                "aichat est manquant. Installer ?",
            ))?;
        if app.cli.yes || ask_install {
            app.log.info(crate::i18n::tr_in(app.lang(), "Installation d'aichat…"));
            crate::commands::install_cmd::run(app, "aichat", None, false, None, None, false)?;
        } else {
            bail!(crate::i18n::tr_in(
                app.lang(),
                "installez aichat: am install aichat — puis réessayez"
            ));
        }
    }

    let prompt = args.prompt.join(" ");
    // Context files: explicit --files wins, else the current directory
    // (issue #96: `aichat -f . "<prompt>"`). The default directory is
    // walked by am to skip noise/vendored/binary files — aichat itself
    // filters nothing and fails on non-UTF-8 content (e.g. .git/index).
    let files: Vec<String> = if args.files.is_empty() {
        context_files(std::path::Path::new("."))
    } else {
        args.files
            .iter()
            .map(|p| p.display().to_string())
            .collect()
    };

    // REPL per-line flags combine with the CLI globals.
    let yes = app.cli.yes || args.yes;
    let dry_run = app.cli.dry_run || args.dry_run;

    let agent = require_agent(app, "aichat")?;

    if !args.exec {
        return chat_mode(app, agent, &prompt, &files, args, dry_run);
    }
    exec_mode(app, &prompt, &files, args, yes, dry_run)
}

/// True when the aichat binary is available (installed or on PATH).
/// Uses a direct PATH lookup — the probe cache would mask a shim added
/// mid-test and is meant for agent inventories, not runtime checks.
fn aichat_installed(app: &App) -> bool {
    app.state.get("aichat").ok().flatten().is_some()
        || which::which("aichat").is_ok()
}

/// Walk `dir` and collect text files usable as aichat context (the
/// default `--files` when the flag is absent). aichat filters nothing
/// and fails on non-UTF-8 content (e.g. `.git/index`), so am pre-filters:
/// - skipped directories: `.git`, vendored/build noise (`target`,
///   `node_modules`, `dist`, `build`, `__pycache__`, `vendor`…);
/// - skipped files: `.env*` (secrets), > 64 KiB, invalid UTF-8.
/// Then the survivors are sorted and taken while a total budget of
/// ~128 KiB holds (≈32K tokens — fits common 64K-token models), capped
/// at 40 files. Empty when nothing qualifies (aichat is called without
/// `-f`).
fn context_files(dir: &std::path::Path) -> Vec<String> {
    const MAX_FILES: usize = 40;
    const MAX_SIZE: u64 = 64 * 1024;
    const TOTAL_BUDGET: u64 = 128 * 1024;
    const SKIP_DIRS: &[&str] = &[
        ".git", "target", "node_modules", "dist", "build", "__pycache__", ".venv", "venv",
        ".idea", ".vscode", ".next", ".cache", "vendor", ".terraform", "coverage", ".gradle",
        ".cargo", "obj", "out", ".svn", ".hg",
    ];
    fn walk(dir: &std::path::Path, out: &mut Vec<(String, u64)>) {
        let Ok(rd) = std::fs::read_dir(dir) else { return };
        for entry in rd.flatten() {
            let path = entry.path();
            let name = entry.file_name();
            let name = name.to_string_lossy();
            if path.is_dir() {
                if SKIP_DIRS.contains(&name.as_ref()) {
                    continue;
                }
                walk(&path, out);
            } else {
                if name.starts_with(".env") {
                    continue;
                }
                let Ok(meta) = entry.metadata() else { continue };
                if meta.len() > MAX_SIZE {
                    continue;
                }
                // UTF-8 sniff on the first bytes — aichat rejects binaries.
                let Ok(mut f) = std::fs::File::open(&path) else { continue };
                use std::io::Read;
                let mut head = Vec::new();
                if f.take(8192).read_to_end(&mut head).is_err()
                    || std::str::from_utf8(&head).is_err()
                {
                    continue;
                }
                out.push((path.display().to_string(), meta.len()));
            }
        }
    }
    let mut found = Vec::new();
    walk(dir, &mut found);
    found.sort();
    let mut files = Vec::new();
    let mut total: u64 = 0;
    for (p, len) in found {
        if files.len() >= MAX_FILES || total + len > TOTAL_BUDGET {
            break;
        }
        total += len;
        files.push(p);
    }
    files
}

/// Build the aichat `--agent` arguments for the requested role. Without a
/// `--role` flag the am-copilot role is used by default (v1.1.2): when its
/// definition is missing the roles are regenerated on the fly, and a
/// generation failure degrades gracefully (no role). An explicit unknown
/// role is an error.
fn role_args(app: &App, role: Option<&str>) -> Result<Vec<String>> {
    let role = role.unwrap_or("am-copilot");
    // aichat >= 0.30 reads functions/agents/<name>/index.yaml; the legacy
    // agents/<name>.md covers aichat <= 0.29 (roles.rs writes both).
    let def = crate::roles::aichat_agent_def_dir(role).join("index.yaml");
    let legacy = crate::roles::aichat_agents_dir().join(format!("{role}.md"));
    let present = || def.exists() || legacy.exists();
    if present() {
        return Ok(vec!["--agent".to_string(), role.to_string()]);
    }
    if role == "am-copilot" {
        if let Err(e) = crate::roles::generate_all(app) {
            app.log.verbose(&format!("roles generation skipped: {e:#}"));
        }
        if present() {
            return Ok(vec!["--agent".to_string(), role.to_string()]);
        }
        app.log.warn(crate::i18n::tr_in(
            app.lang(),
            "rôle 'am-copilot' introuvable — lancez am setup --roles",
        ));
        return Ok(Vec::new());
    }
    bail!(crate::i18n::tr_in(
        app.lang(),
        "rôle '{}' inconnu — générez les rôles avec: am setup --roles (am-copilot, am-operator, am-dev, am-do, am-analyst, am-orchestrator)"
    )
    .replace("{}", role));
}

/// Conversational mode: aichat -f <ctx> "<prompt>" in the foreground, with
/// the provider/model environment applied when requested.
fn chat_mode(
    app: &App,
    agent: &crate::config::AgentDef,
    prompt: &str,
    files: &[String],
    args: &AiArgs,
    dry_run: bool,
) -> Result<i32> {
    let mut extra: Vec<String> = Vec::new();
    extra.extend(role_args(app, args.role.as_deref())?);
    for f in files {
        extra.push("-f".to_string());
        extra.push(f.clone());
    }
    extra.push(prompt.to_string());
    let (p_args, p_env) =
        crate::shell_ai::provider_env(app, args.provider.as_deref(), args.model.as_deref())?;
    extra.extend(p_args);
    if dry_run {
        app.log.dry(&format!(
            "would run aichat {} (conversationnel)",
            extra.join(" ")
        ));
        return Ok(0);
    }
    let exec = resolve_exec(app, agent, &extra, &p_env)?;
    app.log.verbose(&format!(
        "shell-ai: {} {}",
        exec.program,
        exec.args.join(" ")
    ));
    let (prog, prefix) = crate::runner::resolve_program(&exec.program);
    let mut full_args = prefix;
    full_args.extend(exec.args.iter().cloned());
    let status = Command::new(&prog)
        .args(&full_args)
        .envs(&exec.env)
        .status()
        .with_context(|| format!("failed to run {}", exec.program))?;
    app.emit(
        &Event::now(EventKind::ShellAi)
            .with_agent("aichat".to_string())
            .with_args(vec!["mode=chat".to_string(), "executed=true".to_string()]),
    );
    Ok(status.code().unwrap_or(1))
}

/// Exec mode: generate the command (aichat --dry-run), classify it, apply
/// the safety policy, then execute through the shell when allowed.
fn exec_mode(
    app: &App,
    prompt: &str,
    files: &[String],
    args: &AiArgs,
    yes: bool,
    dry_run: bool,
) -> Result<i32> {
    if dry_run {
        app.log.dry(&format!(
            "would generate & classify via aichat (exec) — commande non exécutée"
        ));
    }
    // Exec mode asks for the raw command: default to the am-do role
    // ("Réponds UNIQUEMENT par la commande") unless --role is explicit.
    let role = role_args(app, args.role.as_deref().or(Some("am-do")))?;
    let cmd = crate::shell_ai::generate(
        app,
        prompt,
        files,
        args.provider.as_deref(),
        args.model.as_deref(),
        &role,
    )?;
    let settings = app
        .config
        .settings
        .shell_ai
        .clone()
        .unwrap_or_default();
    let risk = crate::shell_ai::classify(&cmd, &settings.risky_patterns);
    let certainty = crate::shell_ai::estimate_certainty(&cmd, risk);
    let mode = settings.safety_mode();

    // Show the generated command and its classification (issue #97 UX).
    println!("🔒 Commande générée : {}", cmd);
    println!("   Risk     : {}", risk.as_str());
    println!("   Certainty: {}%", certainty);
    println!(
        "   Safety   : {} (settings.shell_ai.default_safety; --yes pour exécuter)",
        mode.as_str()
    );

    let decision = crate::shell_ai::decide(mode, risk, dry_run, yes);
    let lang = app.lang();
    let mut executed = false;
    match decision {
        Decision::Abort => {
            let msg = if dry_run {
                crate::i18n::tr_in(lang, "dry-run : commande non exécutée")
            } else {
                crate::i18n::tr_in(
                    lang,
                    "politique de sécurité (dry-run par défaut) : commande non exécutée — utilisez --yes",
                )
            };
            app.log.info(msg);
        }
        Decision::Ask => {
            let ok = app.confirm(crate::i18n::tr_in(lang, "Exécuter ?"))?;
            if ok {
                executed = true;
            } else {
                app.log.info(crate::i18n::tr_in(lang, "annulé"));
            }
        }
        Decision::Execute => {
            executed = true;
        }
    }
    let code = if executed {
        app.log.info(&format!("exécution: {}", cmd));
        let code = crate::shell_ai::execute(app, &cmd)?;
        code
    } else {
        0
    };
    app.emit(
        &Event::now(EventKind::ShellAi)
            .with_agent("aichat".to_string())
            .with_args(vec![
                "mode=exec".to_string(),
                format!("risk={}", risk.as_str()),
                format!("certainty={certainty}"),
                format!("executed={executed}"),
            ]),
    );
    Ok(code)
}

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

    #[test]
    fn decision_dry_run_is_the_default_policy() {
        // The embedded config does not set shell_ai -> dry-run default.
        let s = crate::config::ShellAiSettings::default();
        assert_eq!(s.safety_mode(), SafetyMode::DryRun);
    }

    #[test]
    fn context_files_skips_binary_noise_and_secrets() {
        let base = std::env::temp_dir().join(format!("am-ai-ctx-{}", std::process::id()));
        let _ = std::fs::remove_dir_all(&base);
        std::fs::create_dir_all(base.join(".git")).unwrap();
        std::fs::create_dir_all(base.join("target")).unwrap();
        std::fs::create_dir_all(base.join("src")).unwrap();
        std::fs::write(base.join("src/a.txt"), "hello").unwrap();
        std::fs::write(base.join("src/b.md"), "# titre").unwrap();
        std::fs::write(base.join(".env"), "TOKEN=secret").unwrap();
        std::fs::write(base.join("bin.dat"), [0u8, 159, 146, 150]).unwrap();
        std::fs::write(base.join(".git/index"), "binary-ish").unwrap();
        std::fs::write(base.join("target/x.rs"), "fn main(){}").unwrap();
        let files = context_files(&base);
        let names: Vec<String> = files
            .iter()
            .map(|p| std::path::Path::new(p).file_name().unwrap().to_string_lossy().to_string())
            .collect();
        assert_eq!(names, vec!["a.txt", "b.md"], "{files:?}");
        let _ = std::fs::remove_dir_all(&base);
    }
}