//! JACS -- JSON AI Communication Standard.
//!
//! Cryptographic signatures for AI agent outputs. Create agent identities,
//! sign documents, verify provenance, and manage trust -- all locally,
//! with no server required.
//!
//! # Getting Started
//!
//! Most users should start with the [`simple`] module, which provides the
//! [`SimpleAgent`](simple::SimpleAgent) facade -- a clean API for the most
//! common operations:
//!
//! ```rust,ignore
//! use jacs::simple::SimpleAgent;
//!
//! let (agent, info) = SimpleAgent::create("my-agent", None, None)?;
//! let signed = agent.sign_message(&serde_json::json!({"hello": "world"}))?;
//! let result = agent.verify(&signed.raw)?;
//! assert!(result.valid);
//! ```
//!
//! # Architecture
//!
//! ```text
//! simple/           Narrow public API (SimpleAgent facade)
//! document/         DocumentService trait -- unified CRUD, versioning, search
//! search/           SearchProvider + EmbeddingProvider traits
//! storage/          Storage backends (filesystem, SQLite, memory, S3)
//! agent/            Agent struct, document traits, security
//! crypt/            Signing, verification, key management
//! schema/           JSON schema validation
//! trust/            Trust store and trust levels
//! dns/              DNS-based key verification
//! ```
//!
//! # Feature Flags
//!
//! | Feature | Default | Description |
//! |---------|---------|-------------|
//! | `sqlite` | Yes | Sync SQLite backend via rusqlite |
//! | `sqlx-sqlite` | No | Async SQLite backend via sqlx + tokio |
//! | `a2a` | No | Agent-to-Agent protocol |
//! | `agreements` | No | Multi-agent agreement signing |
//! | `attestation` | No | Evidence-based attestation |
//! | `otlp-logs` | No | OpenTelemetry log export |
//! | `otlp-metrics` | No | OpenTelemetry metrics export |
//! | `otlp-tracing` | No | OpenTelemetry distributed tracing |

use crate::agent::document::DocumentTraits;
use crate::shared::save_document;
use tracing::error;

use crate::agent::Agent;
use crate::agent::loaders::FileLoader;
use crate::schema::action_crud::create_minimal_action;
use crate::schema::agent_crud::create_minimal_agent;
use crate::schema::service_crud::create_minimal_service;
use crate::schema::task_crud::create_minimal_task;
use serde_json::Value;
use std::path::Path;
use tracing::debug;

#[cfg(feature = "a2a")]
pub mod a2a;
pub mod agent;
pub mod audit;
pub mod config;
pub mod crypt;
pub mod dns;
pub mod document;
pub mod email;
pub mod error;
pub mod health;
pub mod keystore;
pub mod mime;
pub mod observability;
pub mod paths;
pub mod protocol;
pub mod rate_limit;
pub mod replay;
pub mod schema;
pub mod search;
pub mod shared;
pub mod shutdown;
pub mod simple;
pub mod storage;
pub mod testing;
pub mod time_utils;
pub mod trust;
pub mod validation;

#[cfg(feature = "agreements")]
pub mod agreements;

#[cfg(feature = "attestation")]
pub mod attestation;

pub mod cli_utils;
/// The primary error type for all JACS operations.
pub use error::JacsError;

// Re-export health check types for convenience
pub use health::{
    ComponentHealth, HealthCheckResult, HealthStatus, health_check, network_health_check,
};

// Re-export audit types for convenience
pub use audit::{
    AuditOptions, AuditResult, AuditRisk, RiskCategory, RiskSeverity, audit, format_audit_report,
    print_audit_report,
};

// Re-export shutdown types for convenience
pub use shutdown::{ShutdownGuard, install_signal_handler, is_shutdown_requested, shutdown};

// Re-export rate limiting types for convenience
pub use rate_limit::{RateLimitConfig, RateLimiter};

// Re-export observability types for convenience
pub use observability::{
    LogConfig, LogDestination, MetricsConfig, MetricsDestination, ObservabilityConfig,
    ResourceConfig, SamplingConfig, TracingConfig, TracingDestination, init_logging,
    init_observability,
};

// Re-export validation types for convenience
pub use validation::{
    AgentId, are_valid_uuid_parts, format_agent_id, is_valid_agent_id, normalize_agent_id,
    parse_agent_id, require_relative_path_safe, split_agent_id, validate_agent_id,
};

// Re-export time utilities for convenience
pub use time_utils::{
    backup_timestamp_suffix, now_rfc3339, now_timestamp, now_utc, parse_rfc3339,
    parse_rfc3339_to_timestamp, validate_signature_timestamp, validate_timestamp_not_expired,
    validate_timestamp_not_future,
};

/// Initialize observability with a default configuration suitable for most applications.
/// This sets up file-based logging and metrics in the current directory.
pub fn init_default_observability() -> Result<(), JacsError> {
    let config = ObservabilityConfig {
        logs: LogConfig {
            enabled: true,
            level: "info".to_string(),
            destination: LogDestination::File {
                path: "./logs".to_string(),
            },
            headers: None,
        },
        metrics: MetricsConfig {
            enabled: false,
            destination: MetricsDestination::File {
                path: "./metrics.txt".to_string(),
            },
            export_interval_seconds: Some(60),
            headers: None,
        },
        tracing: None,
    };

    init_observability(config).map(|_| ())
}

/// Initialize observability with custom configuration.
/// This is useful when you need specific logging/metrics destinations.
pub fn init_custom_observability(config: ObservabilityConfig) -> Result<(), JacsError> {
    init_observability(config).map(|_| ())
}

/// Creates an empty agent struct with default schema versions.
pub fn get_empty_agent() -> Agent {
    // Use expect as Result handling happens elsewhere or isn't needed here.
    Agent::new(
        config::constants::JACS_AGENT_SCHEMA_VERSION,
        config::constants::JACS_HEADER_SCHEMA_VERSION,
        config::constants::JACS_SIGNATURE_SCHEMA_VERSION,
    )
    .expect("Failed to init Agent in get_empty_agent") // Panic if Agent::new fails
}

fn find_config_for_agent_path(filepath: &str) -> Option<std::path::PathBuf> {
    let mut candidates: Vec<std::path::PathBuf> = Vec::new();

    if let Ok(cwd) = std::env::current_dir() {
        candidates.push(cwd.join("jacs.config.json"));

        let input = Path::new(filepath);
        let absolute_input = if input.is_absolute() {
            input.to_path_buf()
        } else {
            cwd.join(input)
        };

        if let Some(mut dir) = absolute_input.parent().map(|p| p.to_path_buf()) {
            loop {
                candidates.push(dir.join("jacs.config.json"));
                if !dir.pop() {
                    break;
                }
            }
        }
    }

    candidates.into_iter().find(|p| p.exists())
}

fn prepare_agent_for_agent_path(agent: &mut Agent, filepath: &str) {
    let Some(config_path) = find_config_for_agent_path(filepath) else {
        debug!(
            "[load_path_agent] No nearby jacs.config.json found for '{}'; using defaults/env",
            filepath
        );
        return;
    };

    let config_path_str = config_path.to_string_lossy().to_string();
    match crate::config::load_config_12factor_optional(Some(&config_path_str)) {
        Ok(config) => {
            debug!(
                "[load_path_agent] Loaded config context from '{}'",
                config_path.display()
            );
            agent.config = Some(config);
            if let Some(root) = config_path.parent() {
                if let Err(e) = agent.set_storage_root(root.to_path_buf()) {
                    debug!(
                        "[load_path_agent] Failed to re-root storage to '{}': {}",
                        root.display(),
                        e
                    );
                }
            }
        }
        Err(e) => {
            debug!(
                "[load_path_agent] Failed to load config '{}' (continuing with defaults/env): {}",
                config_path.display(),
                e
            );
        }
    }
}

fn default_config_path() -> String {
    std::env::var("JACS_CONFIG")
        .ok()
        .filter(|value| !value.trim().is_empty())
        .unwrap_or_else(|| "./jacs.config.json".to_string())
}

fn apply_dns_policy(
    agent: &mut Agent,
    dns_validate: Option<bool>,
    dns_required: Option<bool>,
    dns_strict: Option<bool>,
) {
    if let Some(validate) = dns_validate {
        agent.set_dns_validate(validate);
    }
    if let Some(required) = dns_required {
        agent.set_dns_required(required);
    }
    if let Some(strict) = dns_strict {
        agent.set_dns_strict(strict);
    }
}

/// Load agent using specific path.
fn load_path_agent(
    filepath: String,
    dns_validate: Option<bool>,
    dns_required: Option<bool>,
    dns_strict: Option<bool>,
) -> Result<Agent, JacsError> {
    debug!("[load_path_agent] Loading from path: {}", filepath);
    let mut agent = get_empty_agent();
    apply_dns_policy(&mut agent, dns_validate, dns_required, dns_strict);
    prepare_agent_for_agent_path(&mut agent, &filepath);

    // Extract filename (e.g., "ID:VERSION.json") from the full path
    let agent_filename = Path::new(&filepath)
        .file_name()
        .and_then(|os_str| os_str.to_str())
        .map(|s| s.to_string())
        .ok_or("Could not extract filename from agent path")?;

    // Strip the .json suffix to get the logical ID
    let agent_id = agent_filename
        .strip_suffix(".json")
        .ok_or("Agent filename does not end with .json")?;

    debug!("[load_path_agent] Extracted agent ID: {}", agent_id);

    // Pass ONLY the logical ID (without .json) to fs_agent_load
    let agent_string = agent
        .fs_agent_load(agent_id) // Pass ID string
        .map_err(|e| format!("Agent file loading failed for ID '{}': {}", agent_id, e))?;

    agent.load(&agent_string)?;
    debug!(
        "[load_path_agent] Agent loaded and validated successfully using ID: {}",
        agent_id
    );
    Ok(agent)
}

/// Load an agent from a file path or default config, with full DNS policy control.
///
/// If `agentfile` is `Some`, loads from the given file path.
/// If `None`, loads from the default config path (`JACS_CONFIG` env var or `./jacs.config.json`).
pub fn load_agent_with_dns_policy(
    agentfile: Option<String>,
    dns_validate: Option<bool>,
    dns_required: Option<bool>,
    dns_strict: Option<bool>,
) -> Result<agent::Agent, JacsError> {
    debug!("load_agent agentfile = {:?}", agentfile);
    if let Some(file) = agentfile {
        load_path_agent(file, dns_validate, dns_required, dns_strict)
    } else {
        let config_path = default_config_path();
        debug!("load_agent defaulting to config path '{}'", config_path);
        let mut agent = get_empty_agent();
        apply_dns_policy(&mut agent, dns_validate, dns_required, dns_strict);
        agent.load_by_config(config_path)?;
        Ok(agent)
    }
}

/// Load an agent from a file path or default config with default DNS policy.
///
/// Convenience wrapper around [`load_agent_with_dns_policy`] with all DNS options set to `None`.
pub fn load_agent(agentfile: Option<String>) -> Result<agent::Agent, JacsError> {
    load_agent_with_dns_policy(agentfile, None, None, None)
}

/// Load an agent from a file path while controlling DNS strictness before validation runs.
pub fn load_agent_with_dns_strict(
    agentfile: String,
    dns_strict: bool,
) -> Result<agent::Agent, JacsError> {
    load_agent_with_dns_policy(Some(agentfile), None, None, Some(dns_strict))
}

/// Creates a minimal agent JSON string with a default service.
/// Optionally accepts descriptions for the default service.
pub fn create_minimal_blank_agent(
    agentype: String,
    service_desc: Option<String>,
    success_desc: Option<String>,
    failure_desc: Option<String>,
) -> Result<String, JacsError> {
    let mut services: Vec<Value> = Vec::new();

    // Use provided descriptions or fall back to defaults.
    let service_description =
        service_desc.unwrap_or_else(|| "Describe a service the agent provides".to_string());
    let success_description = success_desc
        .unwrap_or_else(|| "Describe a success of the service the agent provides".to_string());
    let failure_description = failure_desc.unwrap_or_else(|| {
        "Describe what failure is of the service the agent provides".to_string()
    });

    let service = create_minimal_service(
        &service_description,
        &success_description,
        &failure_description,
        None,
        None,
    )
    .map_err(|e| JacsError::IoError(std::io::Error::new(std::io::ErrorKind::InvalidInput, e)))?;

    services.push(service);

    // Add service
    let agent_value = create_minimal_agent(&agentype, Some(services), None)?;
    Ok(agent_value.to_string())
}

/// Create a signed task document with the given name and description.
///
/// The task is signed by the provided agent and persisted to storage.
/// Returns the validated task JSON string.
pub fn create_task(
    agent: &mut Agent,
    name: String,
    description: String,
) -> Result<String, JacsError> {
    let mut actions: Vec<Value> = Vec::new();
    let action = create_minimal_action(&name, &description, None, None);
    actions.push(action);
    let mut task = create_minimal_task(Some(actions), None, None, None)?;
    task["jacsTaskCustomer"] = agent.signing_procedure(&task, None, "jacsTaskCustomer")?;

    // create document
    let embed = None;
    let docresult = agent
        .create_document_and_load(&task.to_string(), None, embed)
        .map_err(Into::into);

    save_document(agent, docresult, None, None, None, None)?;

    let task_value = agent.get_document(task["id"].as_str().unwrap())?.value;
    let validation_result = agent.schema.taskschema.validate(&task_value);
    match validation_result {
        Ok(_) => Ok(task_value.to_string()),
        Err(err) => {
            let schema_name = task_value
                .get("$schema")
                .and_then(|v| v.as_str())
                .unwrap_or("task.schema.json");
            let error_message = format!(
                "Task creation failed: {}",
                schema::format_schema_validation_error(&err, schema_name, &task_value)
            );
            error!("{}", error_message);
            Err(error_message.into())
        }
    }
}

/// Update a task document (placeholder -- not yet implemented).
pub fn update_task(_: String) -> Result<String, JacsError> {
    // TODO: implement proper task update logic
    Ok("".to_string())
}
