//! Post-install agent configuration (issue #91): the `config:` block of an
//! agent definition wires the resolved provider/model into the agent —
//! the environment variables it expects (env_map) and the config files to
//! write or softly edit (files).
//!
//! Pure functions + per-format tests (probe.rs pattern). Security rule: a
//! token is never written in clear — the api_key slot stays the `@secret`
//! reference (issue #89), resolved from the OS keyring at start/run time.

use crate::app::App;
use crate::config::{AgentDef, Config};
use anyhow::{anyhow, Context, Result};
use std::collections::BTreeMap;
use std::path::Path;

/// The four format families covering ~every agent (spec #91).
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FileFormat {
    Toml,
    Yaml,
    Json,
    KeyValue,
}

impl FileFormat {
    pub fn name(self) -> &'static str {
        match self {
            FileFormat::Toml => "toml",
            FileFormat::Yaml => "yaml",
            FileFormat::Json => "json",
            FileFormat::KeyValue => "key=value",
        }
    }
}

/// Detect the format family from the file extension.
pub fn format_of(path: &Path) -> Option<FileFormat> {
    let ext = path
        .extension()
        .and_then(|e| e.to_str())
        .unwrap_or("")
        .to_ascii_lowercase();
    match ext.as_str() {
        "toml" => Some(FileFormat::Toml),
        "yaml" | "yml" => Some(FileFormat::Yaml),
        "json" => Some(FileFormat::Json),
        "conf" | "ini" | "env" | "properties" | "cfg" => Some(FileFormat::KeyValue),
        _ => None,
    }
}

/// Provider preferred by an agent: `provider:` of the definition, then the
/// `config.provider_default` of its config block (issue #91).
pub fn provider_pref(agent: &AgentDef) -> Option<&str> {
    agent
        .provider
        .as_deref()
        .or(agent.config.as_ref().and_then(|c| c.provider_default.as_deref()))
}

/// Merge the resolved `config.env_map` of an agent into its default env
/// (issue #91): api_key -> `@secret` (resolved by resolve_env_secrets),
/// model/base_url/provider -> values of the resolved provider. Explicit
/// values already present in agent.env are never overwritten.
pub fn apply_env_map(env: &mut BTreeMap<String, String>, agent: &AgentDef, config: &Config) {
    apply_env_map_resolved(env, agent, config, None, None);
}

/// Same as `apply_env_map` but with the provider and model fixed by the
/// caller (issue #92: `am run/start --provider/--model`): the flags win
/// over the agent declaration and the settings default.
pub fn apply_env_map_resolved(
    env: &mut BTreeMap<String, String>,
    agent: &AgentDef,
    config: &Config,
    provider_override: Option<&str>,
    model_override: Option<&str>,
) {
    let Some(cfg) = &agent.config else {
        return;
    };
    if cfg.env_map.is_empty() {
        return;
    }
    let Some(pname) = provider_override
        .filter(|p| !p.is_empty())
        .or_else(|| provider_pref(agent))
        .or_else(|| crate::providers::default_name(config))
    else {
        return;
    };
    let Some(def) = crate::providers::get(config, pname) else {
        return;
    };
    let model = model_override
        .filter(|m| !m.is_empty())
        .or(agent.model.as_deref())
        .or(def.default_model.as_deref());
    for (slot, var) in &cfg.env_map {
        let value = match slot.as_str() {
            "api_key" => "@secret".to_string(),
            "model" => {
                let Some(m) = model else { continue };
                m.to_string()
            }
            "base_url" => def.base_url.clone(),
            "provider" => pname.to_string(),
            _ => continue, // unknown slots are ignored
        };
        env.entry(var.clone()).or_insert(value);
    }
}

/// Write the agent configuration files after a successful install
/// (issue #91). The caller skips this on `--no-config`, on non-configurable
/// agents, and in dry-run (never reached). Never writes a token in clear:
/// the api_key slot is written as the `@secret` reference.
pub fn apply_post_install(
    app: &App,
    agent: &AgentDef,
    resolved: &Option<(String, Option<String>)>,
) -> Result<()> {
    let Some(cfg) = &agent.config else {
        app.log.info(crate::i18n::tr(
            "agent sans adaptateur de config — voir sa doc",
        ));
        return Ok(());
    };
    if cfg.files.is_empty() {
        if cfg.env_map.is_empty() {
            app.log.info(crate::i18n::tr(
                "agent sans adaptateur de config — voir sa doc",
            ));
        } else {
            app.log.info(crate::i18n::tr(
                "config par variables d'env — injectée au démarrage",
            ));
        }
        return Ok(());
    }
    let Some((pname, model)) = resolved else {
        app.log.warn(crate::i18n::tr(
            "aucun provider résolu — fichiers de config non écrits",
        ));
        return Ok(());
    };
    let Some(def) = crate::providers::get(&app.config, pname) else {
        app.log.warn(&crate::tr_fmt!(
            "provider '{}' introuvable — fichiers de config non écrits",
            pname
        ));
        return Ok(());
    };
    for f in &cfg.files {
        let path = crate::config::expand_path(&f.path);
        let Some(fmt) = format_of(&path) else {
            app.log.warn(&crate::tr_fmt!(
                "format inconnu pour {} — adaptateurs: toml, yaml, json, key=value",
                path.display()
            ));
            continue;
        };
        let mut updates: Vec<(String, String)> = Vec::new();
        for key in &f.keys {
            let value = match key.as_str() {
                "api_key" => "@secret".to_string(),
                "model" => model.clone().unwrap_or_default(),
                "base_url" => def.base_url.clone(),
                "provider" => pname.clone(),
                other => {
                    app.log.warn(&crate::tr_fmt!(
                        "clé '{}' inconnue dans config.files de {}",
                        other,
                        agent.name
                    ));
                    continue;
                }
            };
            updates.push((key.clone(), value));
        }
        write_soft(&path, fmt, &updates)?;
        app.log
            .success(&crate::tr_fmt!("config écrite: {}", path.display()));
    }
    Ok(())
}

/// Soft edit of a config file: existing unknown keys are preserved, known
/// keys are updated, missing keys are appended. Creates parent dirs.
pub fn write_soft(path: &Path, format: FileFormat, updates: &[(String, String)]) -> Result<()> {
    if let Some(parent) = path.parent() {
        if !parent.as_os_str().is_empty() {
            std::fs::create_dir_all(parent)
                .with_context(|| format!("cannot create {}", parent.display()))?;
        }
    }
    let text = if path.exists() {
        std::fs::read_to_string(path)
            .with_context(|| format!("cannot read {}", path.display()))?
    } else {
        String::new()
    };
    let out = match format {
        FileFormat::Toml => edit_toml(&text, updates)?,
        FileFormat::Yaml => edit_yaml(&text, updates)?,
        FileFormat::Json => edit_json(&text, updates)?,
        FileFormat::KeyValue => edit_key_value(&text, updates),
    };
    std::fs::write(path, out).with_context(|| format!("cannot write {}", path.display()))?;
    Ok(())
}

/// TOML soft edit. Note: toml::Value does not retain comments on
/// serialization — unknown KEYS are preserved, comments are dropped.
fn edit_toml(text: &str, updates: &[(String, String)]) -> Result<String> {
    let mut root: toml::Value = if text.trim().is_empty() {
        toml::Value::Table(Default::default())
    } else {
        text.parse::<toml::Value>()
            .map_err(|e| anyhow!("invalid TOML: {e}"))?
    };
    let table = root
        .as_table_mut()
        .ok_or_else(|| anyhow!("TOML root is not a table"))?;
    for (k, v) in updates {
        table.insert(k.clone(), toml::Value::String(v.clone()));
    }
    Ok(root.to_string())
}

fn edit_yaml(text: &str, updates: &[(String, String)]) -> Result<String> {
    let mut root: serde_yaml::Value = if text.trim().is_empty() {
        serde_yaml::Value::Mapping(Default::default())
    } else {
        serde_yaml::from_str(text).map_err(|e| anyhow!("invalid YAML: {e}"))?
    };
    let map = root
        .as_mapping_mut()
        .ok_or_else(|| anyhow!("YAML root is not a mapping"))?;
    for (k, v) in updates {
        map.insert(
            serde_yaml::Value::String(k.clone()),
            serde_yaml::Value::String(v.clone()),
        );
    }
    serde_yaml::to_string(&root).map_err(|e| anyhow!("cannot serialize YAML: {e}"))
}

fn edit_json(text: &str, updates: &[(String, String)]) -> Result<String> {
    let mut root: serde_json::Value = if text.trim().is_empty() {
        serde_json::Value::Object(Default::default())
    } else {
        serde_json::from_str(text).map_err(|e| anyhow!("invalid JSON: {e}"))?
    };
    let obj = root
        .as_object_mut()
        .ok_or_else(|| anyhow!("JSON root is not an object"))?;
    for (k, v) in updates {
        obj.insert(k.clone(), serde_json::Value::String(v.clone()));
    }
    serde_json::to_string_pretty(&root).map_err(|e| anyhow!("cannot serialize JSON: {e}"))
}

fn edit_key_value(text: &str, updates: &[(String, String)]) -> String {
    let mut lines: Vec<String> = text.lines().map(String::from).collect();
    let mut seen: BTreeMap<&str, usize> = BTreeMap::new();
    for (i, line) in lines.iter_mut().enumerate() {
        let trimmed = line.trim();
        if trimmed.is_empty()
            || trimmed.starts_with('#')
            || trimmed.starts_with(';')
            || !trimmed.contains('=')
        {
            continue;
        }
        let key = trimmed.split('=').next().unwrap_or("").trim();
        // Case-insensitive match (API_KEY vs api_key in .env files); the
        // existing line keeps its casing.
        if let Some((k, v)) = updates.iter().find(|(k, _)| k.eq_ignore_ascii_case(key)) {
            *line = format!("{key}={v}");
            seen.insert(k, i);
        }
    }
    for (k, v) in updates {
        if !seen.contains_key(k.as_str()) {
            lines.push(format!("{k}={v}"));
        }
    }
    let mut out = lines.join("\n");
    if !out.is_empty() && !out.ends_with('\n') {
        out.push('\n');
    }
    out
}

#[cfg(test)]
mod tests {
    use super::*;
    use clap::Parser;
    use crate::config::{AgentConfig, Config};
    use std::collections::BTreeMap;

    fn updates() -> Vec<(String, String)> {
        vec![
            ("model".to_string(), "gpt-5.2".to_string()),
            ("base_url".to_string(), "https://api.openai.com/v1".to_string()),
            ("api_key".to_string(), "@secret".to_string()),
        ]
    }

    fn tmp(name: &str, content: &str) -> (tempfile::TempDir, std::path::PathBuf) {
        let dir = tempfile::tempdir().unwrap();
        let p = dir.path().join(name);
        if !content.is_empty() {
            std::fs::write(&p, content).unwrap();
        }
        (dir, p)
    }

    #[test]
    fn format_detection_covers_the_four_families() {
        assert_eq!(format_of(Path::new("a.toml")), Some(FileFormat::Toml));
        assert_eq!(format_of(Path::new("a.yaml")), Some(FileFormat::Yaml));
        assert_eq!(format_of(Path::new("a.yml")), Some(FileFormat::Yaml));
        assert_eq!(format_of(Path::new("a.json")), Some(FileFormat::Json));
        assert_eq!(format_of(Path::new("a.conf")), Some(FileFormat::KeyValue));
        assert_eq!(format_of(Path::new("a.env")), Some(FileFormat::KeyValue));
        assert_eq!(format_of(Path::new("a.ini")), Some(FileFormat::KeyValue));
        assert_eq!(format_of(Path::new("a.md")), None);
    }

    #[test]
    fn toml_round_trip_keeps_unknown_keys() {
        let (_d, p) = tmp("c.toml", "# existing\nmodel = \"old\"\ntemperature = 0.7\n");
        write_soft(&p, FileFormat::Toml, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("model = \"gpt-5.2\""), "{out}");
        assert!(
            out.contains("base_url = \"https://api.openai.com/v1\""),
            "{out}"
        );
        assert!(out.contains("api_key = \"@secret\""), "{out}");
        assert!(out.contains("temperature = 0.7"), "unknown key lost: {out}");
    }

    #[test]
    fn toml_creates_the_file_when_missing() {
        let (_d, p) = tmp("new.toml", "");
        write_soft(&p, FileFormat::Toml, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("model = \"gpt-5.2\""), "{out}");
        assert!(out.contains("api_key = \"@secret\""), "{out}");
    }

    #[test]
    fn yaml_round_trip_keeps_unknown_keys() {
        let (_d, p) = tmp("c.yaml", "model: old\nverbose: true\n");
        write_soft(&p, FileFormat::Yaml, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("model: gpt-5.2"), "{out}");
        assert!(out.contains("base_url: https://api.openai.com/v1"), "{out}");
        assert!(out.contains("verbose: true"), "unknown key lost: {out}");
    }

    #[test]
    fn json_round_trip_keeps_unknown_keys() {
        let (_d, p) = tmp("c.json", "{\"model\": \"old\", \"verbose\": true}");
        write_soft(&p, FileFormat::Json, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("\"model\": \"gpt-5.2\""), "{out}");
        assert!(out.contains("\"api_key\": \"@secret\""), "{out}");
        assert!(out.contains("\"verbose\": true"), "unknown key lost: {out}");
    }

    #[test]
    fn key_value_round_trip_keeps_unknown_lines() {
        let (_d, p) = tmp(
            "c.conf",
            "# header\nMODEL=old\nOTHER=keep\n",
        );
        write_soft(&p, FileFormat::KeyValue, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("MODEL=gpt-5.2"), "{out}");
        assert!(out.contains("OTHER=keep"), "unknown line lost: {out}");
        assert!(out.contains("# header"), "comment lost: {out}");
        assert!(out.contains("api_key=@secret"), "{out}");
        // No duplicate MODEL line.
        assert_eq!(out.matches("MODEL=").count(), 1, "{out}");
    }

    #[test]
    fn key_value_appends_missing_keys() {
        let (_d, p) = tmp("empty.env", "");
        write_soft(&p, FileFormat::KeyValue, &updates()).unwrap();
        let out = std::fs::read_to_string(&p).unwrap();
        assert!(out.contains("model=gpt-5.2"), "{out}");
        assert!(out.contains("base_url=https://api.openai.com/v1"), "{out}");
        assert!(out.contains("api_key=@secret"), "{out}");
    }

    fn agent_with_config(config: AgentConfig, provider: Option<String>) -> AgentDef {
        AgentDef {
            name: "x".to_string(),
            display_name: None,
            description: None,
            category: None,
            website: None,
            install: None,
            dependencies: vec![],
            run: Some("x".to_string()),
            detect: None,
            args: vec![],
            env: BTreeMap::new(),
            version: None,
            pin_version: None,
            model_env: None,
            model_arg: None,
            provider,
            model: None,
            config: Some(config),
            sandbox: None,
            tags: vec![],
            installable: false,
            note: None,
            hidden: false,
            platforms: vec![],
            healthcheck: None,
            container: None,
            cost_model: None,
        }
    }

    #[test]
    fn apply_env_map_wires_the_resolved_provider() {
        let mut c: Config = serde_yaml::from_str(
            "version: \"1.0\"\nsettings:\n  default_provider: openai\n  providers:\n    openai:\n      base_url: https://api.openai.com/v1\n      default_model: gpt-5.2\n      models: [gpt-5.2]\n",
        )
        .unwrap();
        let mut env_map = BTreeMap::new();
        env_map.insert("api_key".to_string(), "MY_KEY".to_string());
        env_map.insert("model".to_string(), "MY_MODEL".to_string());
        env_map.insert("base_url".to_string(), "MY_URL".to_string());
        let agent = agent_with_config(
            AgentConfig {
                env_map,
                files: vec![],
                provider_default: None,
            },
            None,
        );
        let mut env = BTreeMap::new();
        apply_env_map(&mut env, &agent, &c);
        assert_eq!(env.get("MY_KEY").unwrap(), "@secret");
        assert_eq!(env.get("MY_MODEL").unwrap(), "gpt-5.2");
        assert_eq!(env.get("MY_URL").unwrap(), "https://api.openai.com/v1");
        // Explicit agent.env values win.
        let mut env2 = BTreeMap::new();
        env2.insert("MY_MODEL".to_string(), "explicit".to_string());
        apply_env_map(&mut env2, &agent, &c);
        assert_eq!(env2.get("MY_MODEL").unwrap(), "explicit");
        // Unset default provider + no provider_default: no-op.
        c.settings.default_provider = None;
        let mut env3 = BTreeMap::new();
        apply_env_map(&mut env3, &agent, &c);
        assert!(env3.is_empty());
    }

    #[test]
    fn apply_post_install_without_config_block_is_a_noop() {
        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,
            "version: \"1.0\"\nsettings:\n  auto_install_deps: false\n  confirm_before_run: false\nagents: []\n",
        )
        .unwrap();
        let cli = crate::cli::Cli::parse_from(["am", "--config", cfg.to_str().unwrap()]);
        let app = crate::app::App::from_cli(cli).unwrap();
        let agent = agent_with_config(
            AgentConfig {
                env_map: BTreeMap::new(),
                files: vec![],
                provider_default: None,
            },
            None,
        );
        // No config block at all → Ok, nothing written.
        let mut bare = agent.clone();
        bare.config = None;
        assert!(apply_post_install(&app, &bare, &None).is_ok());
        // Config block but no files → Ok, nothing written.
        assert!(apply_post_install(&app, &agent, &None).is_ok());
    }

    #[test]
    fn provider_pref_prefers_the_declared_provider() {
        let agent = agent_with_config(
            AgentConfig {
                env_map: BTreeMap::new(),
                files: vec![],
                provider_default: Some("openai".to_string()),
            },
            Some("anthropic".to_string()),
        );
        assert_eq!(provider_pref(&agent), Some("anthropic"));
        let agent2 = agent_with_config(
            AgentConfig {
                env_map: BTreeMap::new(),
                files: vec![],
                provider_default: Some("openai".to_string()),
            },
            None,
        );
        assert_eq!(provider_pref(&agent2), Some("openai"));
    }
}