//! El manifiesto `.swm` (Software Mutación). Ver `docs/06-swm-format.md`.
//!
//! Es la unidad de intercambio: receta de transformación sobre fuente pública + ediciones de
//! config. NUNCA transporta binarios cocidos (salvo `FileDrop` con hash declarado).

use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Swm {
    pub swm_version: u32,
    pub base: Base,
    pub mutations: Vec<Mutation>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub signature: Option<Signature>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Base {
    pub distro_version: String,
    #[serde(default)]
    pub pins: std::collections::BTreeMap<String, String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum Mutation {
    SourcePatch {
        repo: String,
        commit: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        patch: Option<String>,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        patch_url: Option<String>,
        build: SwmBuild,
        target_bin: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        expected_hash: Option<String>,
    },
    ConfigEdit {
        file: String,
        inline_diff: String,
    },
    InitRule {
        action: String,
        service: String,
        command: String,
    },
    FileDrop {
        path: String,
        /// hash BLAKE3 del contenido, declarado para verificación.
        content_hash: String,
        #[serde(default, skip_serializing_if = "Option::is_none")]
        content_url: Option<String>,
    },
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SwmBuild {
    #[serde(default = "default_compiler")]
    pub compiler: String,
    #[serde(default = "default_target")]
    pub target: String,
    #[serde(default = "default_link")]
    pub link: String,
    #[serde(default)]
    pub flags: Vec<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Signature {
    pub by: String,
    pub alg: String,
    pub sig: String,
}

fn default_compiler() -> String {
    "zig-cc".into()
}
fn default_target() -> String {
    "x86_64-linux-musl".into()
}
fn default_link() -> String {
    "static".into()
}

impl Swm {
    pub fn from_yaml(s: &str) -> crate::Result<Swm> {
        serde_yaml::from_str(s).map_err(|e| crate::Error::Serde(e.to_string()))
    }

    pub fn to_yaml(&self) -> crate::Result<String> {
        serde_yaml::to_string(self).map_err(|e| crate::Error::Serde(e.to_string()))
    }
}

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

    #[test]
    fn roundtrip_yaml() {
        let yaml = r#"
swm_version: 1
base:
  distro_version: "2026-06-06"
  pins:
    grep: "a1b2c3d"
mutations:
  - type: config_edit
    file: "/etc/network.conf"
    inline_diff: |
      - DHCP=yes
      + IP=192.168.1.100
"#;
        let swm = Swm::from_yaml(yaml).expect("parse");
        assert_eq!(swm.swm_version, 1);
        assert_eq!(swm.mutations.len(), 1);
        let back = swm.to_yaml().expect("serialize");
        assert!(back.contains("config_edit"));
    }
}