//! AI runtime profile and its context-injection strategy.
//!
//! A profile is *declarative configuration* (see CONTEXT.md §9): adding an AI
//! means adding data, not code (Open/Closed). The [`crate::ports::AgentRuntime`]
//! port is parameterised by an [`AgentProfile`].

use serde::{Deserialize, Serialize};

use crate::error::DomainError;
use crate::ids::ProfileId;

/// Strategy for injecting an agent's `.md` context into the launched CLI.
///
/// Invariants:
/// - `ConventionFile.target` is a relative file name without `..` and not absolute,
/// - `Env.var` is a valid environment-variable identifier,
/// - `Flag.flag` is non-empty.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase", tag = "strategy")]
pub enum ContextInjection {
    /// Write/symlink the `.md` to a conventional file (e.g. `CLAUDE.md`).
    ConventionFile {
        /// Relative target file name.
        target: String,
    },
    /// Pass the context file path through a CLI flag.
    Flag {
        /// The flag template (e.g. `--context-file {path}` or `-f`).
        flag: String,
    },
    /// Pipe the Markdown content on stdin.
    Stdin,
    /// Pass the context via an environment variable.
    Env {
        /// Environment variable name.
        var: String,
    },
}

impl ContextInjection {
    /// Validated `ConventionFile` constructor.
    ///
    /// # Errors
    /// Returns [`DomainError::PathNotRelativeSafe`] if `target` is absolute or
    /// contains `..`.
    pub fn convention_file(target: impl Into<String>) -> Result<Self, DomainError> {
        let target = target.into();
        crate::validation::relative_safe(&target)?;
        Ok(Self::ConventionFile { target })
    }

    /// Validated `Flag` constructor.
    ///
    /// # Errors
    /// Returns [`DomainError::EmptyField`] if `flag` is empty.
    pub fn flag(flag: impl Into<String>) -> Result<Self, DomainError> {
        let flag = flag.into();
        crate::validation::non_empty(&flag, "contextInjection.flag")?;
        Ok(Self::Flag { flag })
    }

    /// `Stdin` constructor (no validation needed).
    #[must_use]
    pub const fn stdin() -> Self {
        Self::Stdin
    }

    /// Validated `Env` constructor.
    ///
    /// # Errors
    /// Returns [`DomainError::InvalidEnvVar`] if `var` is not a valid identifier.
    pub fn env(var: impl Into<String>) -> Result<Self, DomainError> {
        let var = var.into();
        crate::validation::valid_env_var(&var)?;
        Ok(Self::Env { var })
    }
}

/// Declares how IdeA assigns and resumes a CLI conversation, without parsing
/// the model's output (universal, declarative — see CONTEXT.md §9).
///
/// Optional on a profile: a profile without a `session` block behaves as today
/// (no resume).
///
/// Invariants:
/// - `resume_flag` is non-empty,
/// - if `assign_flag` is `Some`, it is non-empty.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct SessionStrategy {
    /// Flag passed on the FIRST launch with a UUID generated by IdeA
    /// (e.g. `"--session-id"`). `None` => degraded mode (resume without id).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub assign_flag: Option<String>,
    /// Resume flag (e.g. `"--resume"` or `"--continue"`).
    pub resume_flag: String,
}

impl SessionStrategy {
    /// Builds a validated session strategy.
    ///
    /// # Errors
    /// Returns [`DomainError::EmptyField`] if `resume_flag` is empty, or if
    /// `assign_flag` is `Some` but empty.
    pub fn new(
        assign_flag: Option<String>,
        resume_flag: impl Into<String>,
    ) -> Result<Self, DomainError> {
        let resume_flag = resume_flag.into();
        crate::validation::non_empty(&resume_flag, "session.resumeFlag")?;
        if let Some(flag) = &assign_flag {
            crate::validation::non_empty(flag, "session.assignFlag")?;
        }
        Ok(Self {
            assign_flag,
            resume_flag,
        })
    }
}

/// Declarative runtime configuration for one AI CLI.
///
/// Invariants:
/// - `name` and `command` non-empty,
/// - `context_injection` is itself valid (guaranteed by its constructors),
/// - `session` is itself valid (guaranteed by its constructor).
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct AgentProfile {
    /// Stable identifier.
    pub id: ProfileId,
    /// Display name.
    pub name: String,
    /// Launch command (e.g. `claude`, `codex`, `gemini`, `aider`).
    pub command: String,
    /// Static arguments.
    pub args: Vec<String>,
    /// Context-injection strategy.
    pub context_injection: ContextInjection,
    /// Optional detection command (e.g. `claude --version`).
    pub detect: Option<String>,
    /// Working-directory template. Always `"{agentRunDir}"` (ARCHITECTURE §14.1):
    /// an agent's PTY cwd is its isolated `.ideai/run/<agent-id>/` directory,
    /// **never** the project root, so that N agents of the same profile never
    /// collide on a single conventional file (`CLAUDE.md`, …) at the root.
    pub cwd_template: String,
    /// Optional conversation assign/resume strategy. Absent (legacy / no resume)
    /// keeps today's behaviour.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub session: Option<SessionStrategy>,
}

/// Embedding strategy of an [`EmbedderProfile`] (LOT C, étage 2 vectoriel).
///
/// Declarative, Open/Closed: a new engine family is a new variant *only* if it
/// changes the adapter's dispatch; otherwise it is pure data on the profile
/// (`model`, `endpoint`, …). The default product posture is [`None`](Self::None):
/// no embedding ⇒ no heavy dependency, recall stays the naïve étage 1.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum EmbedderStrategy {
    /// A local ONNX model run in-process (real integration is a follow-up).
    LocalOnnx,
    /// A local embedding server reached over HTTP (real integration is a follow-up).
    LocalServer,
    /// A remote embedding API (real integration is a follow-up).
    Api,
    /// No embedding engine: recall stays the dependency-free naïve étage 1.
    None,
}

/// Declarative configuration for one embedding engine (LOT C, étage 2).
///
/// Stored in the global IDE store as `embedder.json`, mirroring `profiles.json`
/// for [`AgentProfile`]s: adding an engine is **data, not code** (Open/Closed).
///
/// Invariants:
/// - `id` and `name` non-empty,
/// - `dimension` is non-zero (an embedder always produces fixed-length vectors).
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct EmbedderProfile {
    /// Stable identifier (e.g. `"local-onnx-minilm"`).
    pub id: String,
    /// Display name.
    pub name: String,
    /// Embedding strategy driving which concrete adapter is used.
    pub strategy: EmbedderStrategy,
    /// Model identifier (e.g. an ONNX model name), when the strategy needs one.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub model: Option<String>,
    /// Endpoint URL for a server/API strategy.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub endpoint: Option<String>,
    /// Name of the environment variable carrying the API key (never the key
    /// itself), for an `api` strategy.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub api_key_env: Option<String>,
    /// Length of the vectors this engine produces.
    pub dimension: usize,
}

impl EmbedderProfile {
    /// Builds a validated embedder profile.
    ///
    /// # Errors
    /// - [`DomainError::EmptyField`] if `id` or `name` is empty,
    /// - [`DomainError::EmptyField`] (`"embedder.dimension"`) if `dimension` is `0`.
    pub fn new(
        id: impl Into<String>,
        name: impl Into<String>,
        strategy: EmbedderStrategy,
        model: Option<String>,
        endpoint: Option<String>,
        api_key_env: Option<String>,
        dimension: usize,
    ) -> Result<Self, DomainError> {
        let id = id.into();
        let name = name.into();
        crate::validation::non_empty(&id, "embedder.id")?;
        crate::validation::non_empty(&name, "embedder.name")?;
        if dimension == 0 {
            return Err(DomainError::EmptyField {
                field: "embedder.dimension",
            });
        }
        Ok(Self {
            id,
            name,
            strategy,
            model,
            endpoint,
            api_key_env,
            dimension,
        })
    }

    /// A dependency-free default profile: strategy [`EmbedderStrategy::None`].
    /// Recall stays the naïve étage 1 — nothing is imposed.
    #[must_use]
    pub fn none() -> Self {
        Self {
            id: "none".to_owned(),
            name: "None".to_owned(),
            strategy: EmbedderStrategy::None,
            model: None,
            endpoint: None,
            api_key_env: None,
            dimension: 1,
        }
    }
}

impl AgentProfile {
    /// Builds a validated profile.
    ///
    /// # Errors
    /// Returns [`DomainError::EmptyField`] if `name` or `command` is empty.
    #[allow(clippy::too_many_arguments)]
    pub fn new(
        id: ProfileId,
        name: impl Into<String>,
        command: impl Into<String>,
        args: Vec<String>,
        context_injection: ContextInjection,
        detect: Option<String>,
        cwd_template: impl Into<String>,
        session: Option<SessionStrategy>,
    ) -> Result<Self, DomainError> {
        let name = name.into();
        let command = command.into();
        let cwd_template = cwd_template.into();
        crate::validation::non_empty(&name, "profile.name")?;
        crate::validation::non_empty(&command, "profile.command")?;
        Ok(Self {
            id,
            name,
            command,
            args,
            context_injection,
            detect,
            cwd_template,
            session,
        })
    }
}