//! config subcommands: show, path, edit, validate, add.

use super::*;
use crate::cli::ConfigCmd;
use crate::config;
use crate::output::print_json;
use anyhow::{anyhow, Context, Result};
use clap::Parser;
use std::path::{Path, PathBuf};
use std::process::Command;

const USER_CONFIG_TEMPLATE: &str = "# User configuration for agent-manager.
# This file overrides/completes the embedded default catalog.
# Run 'am config show' to see the effective configuration.
version: \"1.0\"

agents: []
";

pub fn run(app: &App, cmd: &ConfigCmd) -> Result<i32> {
    match cmd {
        ConfigCmd::Show => {
            if app.json() {
                print_json(&app.config);
            } else {
                println!("{}", serde_yaml::to_string(&app.config)?);
            }
            Ok(0)
        }
        ConfigCmd::Path => {
            if app.json() {
                print_json(&serde_json::json!({
                    "origin": app.config_origin.as_ref().map(|p| p.display().to_string()),
                    "user_dir": app.paths.config_dir.as_ref().map(|p| p.display().to_string()),
                    "user_file": user_config_path_if_any(app).map(|p| p.display().to_string()),
                    "local_file": PathBuf::from(config::LOCAL_CONFIG_NAME).display().to_string(),
                }));
            } else {
                match &app.config_origin {
                    Some(p) => println!("active config: {}", p.display()),
                    None => println!("no user config found — using the embedded default catalog"),
                }
                if let Some(d) = &app.paths.config_dir {
                    println!("user config directory: {}", d.display());
                    println!(
                        "user config file:      {}",
                        d.join(config::CONFIG_FILE_NAME).display()
                    );
                }
                println!(
                    "local config file:    {} (current directory)",
                    PathBuf::from(config::LOCAL_CONFIG_NAME).display()
                );
            }
            Ok(0)
        }
        ConfigCmd::Validate => {
            let problems = config::validate(&app.config);
            if app.json() {
                print_json(&serde_json::json!({
                    "valid": problems.is_empty(),
                    "problems": problems,
                }));
                return Ok(if problems.is_empty() { 0 } else { 1 });
            }
            if problems.is_empty() {
                app.log
                    .success(&format!("configuration is valid ({} agents)", app.catalog.len()));
                Ok(0)
            } else {
                app.log.error(&format!(
                    "configuration problems:
  - {}",
                    problems.join("
  - ")
                ));
                Ok(1)
            }
        }
        ConfigCmd::Edit => {
            let path = user_config_path(app)?;
            let editor = std::env::var("VISUAL")
                .or_else(|_| std::env::var("EDITOR"))
                .unwrap_or_else(|_| {
                    if cfg!(windows) {
                        "notepad".to_string()
                    } else {
                        "vi".to_string()
                    }
                });
            let status = Command::new(&editor)
                .arg(&path)
                .status()
                .with_context(|| format!("cannot launch editor '{editor}'"))?;
            Ok(status.code().unwrap_or(1))
        }
        ConfigCmd::Add { file } => add_file(app, file),
        ConfigCmd::Set { key, value } => set_value(app, key, value),
    }
}

/// config set: set one dotted key (e.g. settings.default_shell) in the user
/// configuration file, then validate the result.
pub fn set_value(app: &App, key: &str, value: &str) -> Result<i32> {
    let path = user_config_path(app)?;
    write_dotted_key(&path, key, value)?;
    reload_and_validate(&path)?;
    app.log.success(&format!("{key} = {value}"));
    Ok(0)
}

/// Persist one setting into the configuration file that is actually in
/// effect (the loaded origin), creating the user config file when none
/// exists. Used by the REPL 'theme <name>' command so a switched theme
/// survives a restart.
pub fn persist_setting(app: &App, key: &str, value: &str) -> Result<()> {
    let path = match &app.config_origin {
        Some(p) => p.clone(),
        None => user_config_path(app)?,
    };
    write_dotted_key(&path, key, value)?;
    reload_and_validate(&path)
}

/// Set one dotted key (e.g. settings.default_shell) in a YAML config file.
fn write_dotted_key(path: &Path, key: &str, value: &str) -> Result<()> {
    let text = std::fs::read_to_string(path)
        .with_context(|| format!("cannot read {}", path.display()))?;
    let mut root: serde_yaml::Value = serde_yaml::from_str(&text)
        .with_context(|| format!("{} is not valid YAML", path.display()))?;

    let parts: Vec<&str> = key.split('.').collect();
    if parts.is_empty() || parts.iter().any(|p| p.is_empty()) {
        return Err(anyhow!("invalid key '{key}' — expected a dotted path like settings.default_shell"));
    }
    let parsed = parse_scalar(value);
    let mut node = root
        .as_mapping_mut()
        .ok_or_else(|| anyhow!("{} must contain a YAML mapping", path.display()))?;
    for part in &parts[..parts.len() - 1] {
        let entry = node
            .entry(serde_yaml::Value::String(part.to_string()))
            .or_insert_with(|| serde_yaml::Value::Mapping(Default::default()));
        node = entry
            .as_mapping_mut()
            .ok_or_else(|| anyhow!("'{part}' is not a mapping — cannot descend into it"))?;
    }
    node.insert(
        serde_yaml::Value::String(parts.last().unwrap().to_string()),
        parsed,
    );
    std::fs::write(path, serde_yaml::to_string(&root)?)
        .with_context(|| format!("cannot write {}", path.display()))?;
    Ok(())
}

/// Reload a written config file to make sure the change stays valid.
fn reload_and_validate(path: &Path) -> Result<()> {
    let cli = crate::cli::Cli::parse_from(["am", "--config", path.to_str().unwrap_or_default()]);
    config::load(&cli).map_err(|e| {
        anyhow!("the new value makes the configuration invalid: {e:#}")
    })?;
    Ok(())
}

/// Parse a scalar: booleans and integers keep their type, everything else
/// stays a string.
fn parse_scalar(value: &str) -> serde_yaml::Value {
    if let Ok(b) = value.parse::<bool>() {
        return serde_yaml::Value::Bool(b);
    }
    if let Ok(i) = value.parse::<i64>() {
        return serde_yaml::Value::Number(i.into());
    }
    serde_yaml::Value::String(value.to_string())
}

fn user_config_path_if_any(app: &App) -> Option<PathBuf> {
    app.paths
        .config_dir
        .as_ref()
        .map(|d| d.join(config::CONFIG_FILE_NAME))
}

/// Ensure the user config file exists (creating a template when needed).
fn user_config_path(app: &App) -> Result<PathBuf> {
    let dir = app
        .paths
        .config_dir
        .clone()
        .ok_or_else(|| anyhow!("cannot determine the user config directory (no HOME set)"))?;
    std::fs::create_dir_all(&dir)
        .with_context(|| format!("cannot create {}", dir.display()))?;
    let path = dir.join(config::CONFIG_FILE_NAME);
    if !path.exists() {
        std::fs::write(&path, USER_CONFIG_TEMPLATE)
            .with_context(|| format!("cannot create {}", path.display()))?;
    }
    Ok(path)
}

/// config add: copy an agent definition file into the config dir and
/// register it via an include entry in the user config file.
fn add_file(app: &App, file: &Path) -> Result<i32> {
    config::parse_file(file)?;
    let dir = app
        .paths
        .config_dir
        .clone()
        .ok_or_else(|| anyhow!("cannot determine the user config directory (no HOME set)"))?;
    std::fs::create_dir_all(&dir)?;
    let base = file
        .file_name()
        .and_then(|n| n.to_str())
        .unwrap_or("agents.yaml")
        .to_string();
    let dest = dir.join(&base);
    std::fs::copy(file, &dest)
        .with_context(|| format!("cannot copy {} to {}", file.display(), dest.display()))?;
    register_include(app, &base)?;
    app.log.success(&format!(
        "added {} and registered it in {}",
        dest.display(),
        user_config_path(app)?.display()
    ));
    Ok(0)
}

/// Read the `include:` entries of the user config file (they are consumed
/// at load time, so the resolved config no longer lists them).
pub fn user_includes(app: &App) -> Vec<String> {
    let Some(cfg_path) = user_config_path_if_any(app) else {
        return Vec::new();
    };
    let Ok(text) = std::fs::read_to_string(&cfg_path) else {
        return Vec::new();
    };
    let Ok(value) = serde_yaml::from_str::<serde_yaml::Value>(&text) else {
        return Vec::new();
    };
    value
        .get("include")
        .and_then(|i| i.as_sequence())
        .map(|seq| {
            seq.iter()
                .filter_map(|v| v.as_str().map(|s| s.to_string()))
                .collect()
        })
        .unwrap_or_default()
}

/// Add one entry to the `include:` list of the user config file (creating
/// the file with a template when it does not exist). Used by 'config add'
/// (local files) and 'catalog add/update' (remote URLs, issues #60 #67).
pub fn register_include(app: &App, entry: &str) -> Result<()> {
    let cfg_path = user_config_path(app)?;
    let text = std::fs::read_to_string(&cfg_path)?;
    let mut value: serde_yaml::Value = serde_yaml::from_str(&text)
        .unwrap_or_else(|_| serde_yaml::Value::Null);
    match &mut value {
        serde_yaml::Value::Mapping(map) => {
            let key = serde_yaml::Value::String("include".to_string());
            match map.get_mut(&key) {
                Some(serde_yaml::Value::Sequence(seq)) => {
                    let entry = serde_yaml::Value::String(entry.to_string());
                    if !seq.contains(&entry) {
                        seq.push(entry);
                    }
                }
                _ => {
                    map.insert(
                        key,
                        serde_yaml::Value::Sequence(vec![serde_yaml::Value::String(
                            entry.to_string(),
                        )]),
                    );
                }
            }
            std::fs::write(&cfg_path, serde_yaml::to_string(&value)?)
                .with_context(|| format!("cannot write {}", cfg_path.display()))?;
        }
        _ => {
            std::fs::write(
                &cfg_path,
                format!("version: \"1.0\"\ninclude:\n  - {entry}\n"),
            )?;
        }
    }
    Ok(())
}

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

    /// App whose active config is a file inside a leaked TempDir (the same
    /// pattern as profile_cmd's tests: the guard would delete the directory
    /// when the helper returns).
    fn app_with_config(text: &str) -> (App, PathBuf) {
        let guard = tempfile::tempdir().unwrap();
        let dir = guard.path().to_path_buf();
        std::mem::forget(guard);
        let cfg = dir.join("config.yaml");
        std::fs::write(&cfg, text).unwrap();
        let cli = crate::cli::Cli::parse_from(["am", "--config", cfg.to_str().unwrap()]);
        let mut app = App::from_cli(cli).unwrap();
        let mut p = app.paths.clone();
        p.install_dir = dir.join("agents");
        p.bin_dir = dir.join("agents").join("bin");
        p.log_dir = dir.join("logs");
        p.state_file = dir.join("state.json");
        p.probe_cache_file = dir.join("probe-cache.json");
        p.config_dir = Some(dir.join("config"));
        app.paths = p;
        (app, cfg)
    }

    #[test]
    fn persist_setting_writes_into_the_active_config() {
        let (app, cfg) = app_with_config("version: \"1.0\"
settings:
  theme: default
agents: []
");
        persist_setting(&app, "settings.theme", "ocean").unwrap();
        let text = std::fs::read_to_string(&cfg).unwrap();
        let value: serde_yaml::Value = serde_yaml::from_str(&text).unwrap();
        assert_eq!(value["settings"]["theme"], "ocean");
    }

    #[test]
    fn persisted_theme_is_used_on_next_start() {
        let (app, cfg) = app_with_config("version: \"1.0\"
settings:
  theme: default
agents: []
");
        persist_setting(&app, "settings.theme", "ocean").unwrap();
        // A fresh start reads settings.theme from the config file.
        let cli = crate::cli::Cli::parse_from(["am", "--config", cfg.to_str().unwrap()]);
        let reloaded = App::from_cli(cli).unwrap();
        assert_eq!(reloaded.theme().name, "ocean");
    }

    #[test]
    fn persist_setting_creates_the_user_config_when_none_exists() {
        let (mut app, _cfg) = app_with_config("version: \"1.0\"
agents: []
");
        // Simulate a run without any user/local config: no origin.
        app.config_origin = None;
        persist_setting(&app, "settings.theme", "mono").unwrap();
        let user_file = app.paths.config_dir.as_ref().unwrap().join(config::CONFIG_FILE_NAME);
        assert!(user_file.is_file(), "user config was not created");
        let text = std::fs::read_to_string(&user_file).unwrap();
        let value: serde_yaml::Value = serde_yaml::from_str(&text).unwrap();
        assert_eq!(value["settings"]["theme"], "mono");
    }

    #[test]
    fn write_dotted_key_descends_into_nested_mappings() {
        let guard = tempfile::tempdir().unwrap();
        let path = guard.path().join("c.yaml");
        std::fs::write(&path, "version: \"1.0\"
agents: []
").unwrap();
        write_dotted_key(&path, "settings.default_shell", "pwsh").unwrap();
        let value: serde_yaml::Value =
            serde_yaml::from_str(&std::fs::read_to_string(&path).unwrap()).unwrap();
        assert_eq!(value["settings"]["default_shell"], "pwsh");
        assert!(value["agents"].is_sequence());
    }
}