//! export/import: back up the configuration and installation state.

use super::*;
use crate::config::{Config, Settings};
use crate::state::StateFile;
use crate::output::print_json;
use anyhow::{anyhow, Context, Result};
use serde::{Deserialize, Serialize};
use std::path::Path;

#[derive(Serialize, Deserialize)]
struct ExportFile {
    tool: String,
    version: String,
    generated_at: String,
    config: Config,
    state: StateFile,
}

pub fn export_cmd(app: &App, output: &Path) -> Result<i32> {
    let export = ExportFile {
        tool: "agent-manager".to_string(),
        version: env!("CARGO_PKG_VERSION").to_string(),
        generated_at: crate::installers::now_rfc3339(),
        config: app.config.clone(),
        state: app.state.load()?,
    };
    if app.dry_run() {
        app.log
            .dry(format!("would write {}", output.display()));
        return Ok(0);
    }
    let text = serde_json::to_string_pretty(&export)?;
    std::fs::write(output, text)
        .with_context(|| format!("cannot write {}", output.display()))?;
    app.log
        .success(&format!("exported config + state to {}", output.display()));
    Ok(0)
}

pub fn import_cmd(app: &App, file: &Path) -> Result<i32> {
    let text = std::fs::read_to_string(file)
        .with_context(|| format!("cannot read {}", file.display()))?;
    let export: ExportFile = serde_json::from_str(&text)
        .with_context(|| format!("{} is not a valid agent-manager export", file.display()))?;
    if app.dry_run() {
        app.log
            .dry(format!("would import from {}", file.display()));
        return Ok(0);
    }

    // State: merge entries (existing ones win).
    let mut sf = app.state.load()?;
    let mut imported_state = 0;
    for (name, entry) in export.state.installed {
        if !sf.installed.contains_key(&name) {
            sf.installed.insert(name, entry);
            imported_state += 1;
        }
    }
    app.state.save(&sf)?;

    // Config: write the exported agents to a file and include it.
    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 ts = chrono::Local::now().format("%Y%m%d-%H%M%S");
    let fname = format!("imported-{ts}.yaml");
    let dest = dir.join(&fname);
    let cfg = Config {
        version: "1.0".to_string(),
        settings: Settings::default(),
        aliases: Default::default(),
        groups: Default::default(),
        include: vec![],
        agents: export.config.agents.clone(),
        projects: Default::default(),
        profiles: export.config.profiles.clone(),
    };
    std::fs::write(&dest, serde_yaml::to_string(&cfg)?)
        .with_context(|| format!("cannot write {}", dest.display()))?;

    let cfg_path = dir.join(crate::config::CONFIG_FILE_NAME);
    if !cfg_path.exists() {
        std::fs::write(
            &cfg_path,
            format!("version: \"1.0\"\ninclude:\n  - {fname}\n"),
        )?;
    } else {
        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);
        if let serde_yaml::Value::Mapping(map) = &mut value {
            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(fname.clone());
                    if !seq.contains(&entry) {
                        seq.push(entry);
                    }
                }
                _ => {
                    map.insert(
                        key,
                        serde_yaml::Value::Sequence(vec![serde_yaml::Value::String(
                            fname.clone(),
                        )]),
                    );
                }
            }
            std::fs::write(&cfg_path, serde_yaml::to_string(&value)?)?;
        }
    }

    if app.json() {
        print_json(&serde_json::json!({
            "agents_imported": export.config.agents.len(),
            "state_entries_imported": imported_state,
            "config_file": dest.display().to_string(),
        }));
    } else {
        app.log.success(&format!(
            "imported {} agent definition(s) and {} state entrie(s) from {}",
            export.config.agents.len(),
            imported_state,
            file.display()
        ));
        app.log.info(&format!(
            "definitions written to {}",
            dest.display()
        ));
    }
    Ok(0)
}