//! Instance and community settings API endpoints.

use axum::{
    extract::{Path, State},
    routing::{get, patch, post},
    Extension,
    Json, Router,
};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use sqlx::PgPool;
use std::sync::Arc;
use uuid::Uuid;

use crate::auth::AuthUser;
use crate::config::Config;
use super::permissions::{require_permission, require_any_permission, perms};
use axum::http::StatusCode;

// ============================================================================
// Types
// ============================================================================

#[derive(Debug, Serialize)]
pub struct SetupStatus {
    pub setup_required: bool,
    pub instance_name: Option<String>,
}

#[derive(Debug, Serialize)]
pub struct PublicInstanceSettings {
    pub setup_completed: bool,
    pub instance_name: String,
    pub platform_mode: String,
    pub registration_enabled: bool,
    pub registration_mode: String,
    pub single_community_slug: Option<String>,
    pub single_community_name: Option<String>,
}

#[derive(Debug, Serialize)]
pub struct InstanceSettings {
    pub id: Uuid,
    pub setup_completed: bool,
    pub instance_name: String,
    pub platform_mode: String,
    pub registration_enabled: bool,
    pub registration_mode: String,
    pub default_community_visibility: String,
    pub allow_private_communities: bool,
    pub default_plugin_policy: String,
    pub default_moderation_mode: String,
}

#[derive(Debug, Deserialize)]
pub struct SetupRequest {
    pub instance_name: String,
    pub platform_mode: String,
    #[serde(default)]
    pub single_community_name: Option<String>,
}

#[derive(Debug, Deserialize)]
pub struct UpdateInstanceRequest {
    #[serde(default)]
    pub instance_name: Option<String>,
    #[serde(default)]
    pub platform_mode: Option<String>,
    #[serde(default)]
    pub registration_enabled: Option<bool>,
    #[serde(default)]
    pub registration_mode: Option<String>,
}

#[derive(Debug, Serialize)]
pub struct CommunitySettings {
    pub community_id: Uuid,
    pub membership_mode: String,
    pub moderation_mode: String,
    pub governance_model: String,
    pub plugin_policy: String,
    pub features_enabled: Value,
}

#[derive(Debug, Deserialize)]
pub struct UpdateCommunitySettingsRequest {
    #[serde(default)]
    pub membership_mode: Option<String>,
    #[serde(default)]
    pub moderation_mode: Option<String>,
    #[serde(default)]
    pub governance_model: Option<String>,
    #[serde(default)]
    pub plugin_policy: Option<String>,
}

// ============================================================================
// Handlers
// ============================================================================

/// Check if setup is required (public endpoint)
async fn get_setup_status(State(pool): State<PgPool>) -> Result<Json<SetupStatus>, String> {
    let row = sqlx::query!(
        "SELECT setup_completed, instance_name FROM instance_settings LIMIT 1"
    )
    .fetch_optional(&pool)
    .await
    .map_err(|e| e.to_string())?;

    match row {
        Some(r) => Ok(Json(SetupStatus {
            setup_required: !r.setup_completed,
            instance_name: Some(r.instance_name),
        })),
        None => Ok(Json(SetupStatus {
            setup_required: true,
            instance_name: None,
        })),
    }
}

/// Public instance settings (no auth)
async fn get_public_settings(State(pool): State<PgPool>) -> Result<Json<PublicInstanceSettings>, String> {
    let row = sqlx::query!(
        r#"SELECT setup_completed, instance_name, platform_mode,
                  registration_enabled, registration_mode,
                  single_community_id
           FROM instance_settings
           LIMIT 1"#
    )
    .fetch_optional(&pool)
    .await
    .map_err(|e| e.to_string())?;

    let Some(r) = row else {
        return Ok(Json(PublicInstanceSettings {
            setup_completed: false,
            instance_name: "Likwid".to_string(),
            platform_mode: "open".to_string(),
            registration_enabled: true,
            registration_mode: "open".to_string(),
            single_community_slug: None,
            single_community_name: None,
        }));
    };

    let mut single_community_slug: Option<String> = None;
    let mut single_community_name: Option<String> = None;

    if let Some(cid) = r.single_community_id {
        let comm = sqlx::query!("SELECT slug, name FROM communities WHERE id = $1", cid)
            .fetch_optional(&pool)
            .await
            .map_err(|e| e.to_string())?;

        if let Some(c) = comm {
            single_community_slug = Some(c.slug);
            single_community_name = Some(c.name);
        }
    }

    Ok(Json(PublicInstanceSettings {
        setup_completed: r.setup_completed,
        instance_name: r.instance_name,
        platform_mode: r.platform_mode,
        registration_enabled: r.registration_enabled,
        registration_mode: r.registration_mode,
        single_community_slug,
        single_community_name,
    }))
}

/// Complete initial setup
async fn complete_setup(
    State(pool): State<PgPool>,
    auth: AuthUser,
    Json(req): Json<SetupRequest>,
) -> Result<Json<InstanceSettings>, (StatusCode, String)> {
    // Check platform admin permission
    require_permission(&pool, auth.user_id, perms::PLATFORM_ADMIN, None).await?;

    // Check if already set up
    let existing = sqlx::query!("SELECT setup_completed FROM instance_settings LIMIT 1")
        .fetch_optional(&pool)
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    if existing.map(|e| e.setup_completed).unwrap_or(false) {
        return Err((StatusCode::BAD_REQUEST, "Setup already completed".to_string()));
    }

    // Handle single_community mode
    let single_community_id: Option<Uuid> = if req.platform_mode == "single_community" {
        let name = req.single_community_name.as_deref().unwrap_or("Main Community");
        let community = sqlx::query!(
            r#"INSERT INTO communities (name, slug, description, is_active, created_by)
               VALUES ($1, $2, $3, true, $4)
               RETURNING id"#,
            name,
            slug::slugify(name),
            format!("The {} community", name),
            auth.user_id
        )
        .fetch_one(&pool)
        .await
        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;
        Some(community.id)
    } else {
        None
    };

    // Update settings
    let settings = sqlx::query!(
        r#"UPDATE instance_settings SET
            setup_completed = true,
            setup_completed_at = NOW(),
            setup_completed_by = $1,
            instance_name = $2,
            platform_mode = $3,
            single_community_id = $4
           RETURNING id, setup_completed, instance_name, platform_mode,
                     registration_enabled, registration_mode,
                     default_community_visibility, allow_private_communities,
                     default_plugin_policy, default_moderation_mode"#,
        auth.user_id,
        req.instance_name,
        req.platform_mode,
        single_community_id
    )
    .fetch_one(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    Ok(Json(InstanceSettings {
        id: settings.id,
        setup_completed: settings.setup_completed,
        instance_name: settings.instance_name,
        platform_mode: settings.platform_mode,
        registration_enabled: settings.registration_enabled,
        registration_mode: settings.registration_mode,
        default_community_visibility: settings.default_community_visibility,
        allow_private_communities: settings.allow_private_communities,
        default_plugin_policy: settings.default_plugin_policy,
        default_moderation_mode: settings.default_moderation_mode,
    }))
}

/// Get instance settings (admin only)
async fn get_instance_settings(
    State(pool): State<PgPool>,
    auth: AuthUser,
) -> Result<Json<InstanceSettings>, (StatusCode, String)> {
    // Check platform settings permission
    require_permission(&pool, auth.user_id, perms::PLATFORM_SETTINGS, None).await?;

    let s = sqlx::query!(
        r#"SELECT id, setup_completed, instance_name, platform_mode,
                  registration_enabled, registration_mode,
                  default_community_visibility, allow_private_communities,
                  default_plugin_policy, default_moderation_mode
           FROM instance_settings LIMIT 1"#
    )
    .fetch_one(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    Ok(Json(InstanceSettings {
        id: s.id,
        setup_completed: s.setup_completed,
        instance_name: s.instance_name,
        platform_mode: s.platform_mode,
        registration_enabled: s.registration_enabled,
        registration_mode: s.registration_mode,
        default_community_visibility: s.default_community_visibility,
        allow_private_communities: s.allow_private_communities,
        default_plugin_policy: s.default_plugin_policy,
        default_moderation_mode: s.default_moderation_mode,
    }))
}

/// Update instance settings (admin only)
async fn update_instance_settings(
    State(pool): State<PgPool>,
    auth: AuthUser,
    Extension(config): Extension<Arc<Config>>,
    Json(req): Json<UpdateInstanceRequest>,
) -> Result<Json<InstanceSettings>, (StatusCode, String)> {
    // Check platform settings permission
    require_permission(&pool, auth.user_id, perms::PLATFORM_SETTINGS, None).await?;

    if config.is_demo() {
        return Err((
            StatusCode::FORBIDDEN,
            "Instance settings cannot be modified in demo mode".to_string(),
        ));
    }

    let s = sqlx::query!(
        r#"UPDATE instance_settings SET
            instance_name = COALESCE($1, instance_name),
            platform_mode = COALESCE($2, platform_mode),
            registration_enabled = COALESCE($3, registration_enabled),
            registration_mode = COALESCE($4, registration_mode)
           RETURNING id, setup_completed, instance_name, platform_mode,
                     registration_enabled, registration_mode,
                     default_community_visibility, allow_private_communities,
                     default_plugin_policy, default_moderation_mode"#,
        req.instance_name,
        req.platform_mode,
        req.registration_enabled,
        req.registration_mode
    )
    .fetch_one(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    Ok(Json(InstanceSettings {
        id: s.id,
        setup_completed: s.setup_completed,
        instance_name: s.instance_name,
        platform_mode: s.platform_mode,
        registration_enabled: s.registration_enabled,
        registration_mode: s.registration_mode,
        default_community_visibility: s.default_community_visibility,
        allow_private_communities: s.allow_private_communities,
        default_plugin_policy: s.default_plugin_policy,
        default_moderation_mode: s.default_moderation_mode,
    }))
}

/// Get community settings
async fn get_community_settings(
    State(pool): State<PgPool>,
    Path(community_id): Path<Uuid>,
) -> Result<Json<CommunitySettings>, (StatusCode, String)> {
    // Ensure settings exist
    sqlx::query!(
        "INSERT INTO community_settings (community_id) VALUES ($1) ON CONFLICT DO NOTHING",
        community_id
    )
    .execute(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let s = sqlx::query!(
        r#"SELECT community_id, membership_mode, moderation_mode,
                  governance_model, plugin_policy, features_enabled
           FROM community_settings WHERE community_id = $1"#,
        community_id
    )
    .fetch_one(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    Ok(Json(CommunitySettings {
        community_id: s.community_id,
        membership_mode: s.membership_mode,
        moderation_mode: s.moderation_mode,
        governance_model: s.governance_model,
        plugin_policy: s.plugin_policy,
        features_enabled: s.features_enabled,
    }))
}

/// Update community settings
async fn update_community_settings(
    State(pool): State<PgPool>,
    auth: AuthUser,
    Path(community_id): Path<Uuid>,
    Json(req): Json<UpdateCommunitySettingsRequest>,
) -> Result<Json<CommunitySettings>, (StatusCode, String)> {
    // Check community settings permission (community admin or platform admin)
    require_any_permission(
        &pool,
        auth.user_id,
        &[perms::COMMUNITY_SETTINGS, perms::PLATFORM_ADMIN],
        Some(community_id),
    ).await?;

    // Ensure settings exist
    sqlx::query!(
        "INSERT INTO community_settings (community_id) VALUES ($1) ON CONFLICT DO NOTHING",
        community_id
    )
    .execute(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    let s = sqlx::query!(
        r#"UPDATE community_settings SET
            membership_mode = COALESCE($2, membership_mode),
            moderation_mode = COALESCE($3, moderation_mode),
            governance_model = COALESCE($4, governance_model),
            plugin_policy = COALESCE($5, plugin_policy)
           WHERE community_id = $1
           RETURNING community_id, membership_mode, moderation_mode,
                     governance_model, plugin_policy, features_enabled"#,
        community_id,
        req.membership_mode,
        req.moderation_mode,
        req.governance_model,
        req.plugin_policy
    )
    .fetch_one(&pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()))?;

    Ok(Json(CommunitySettings {
        community_id: s.community_id,
        membership_mode: s.membership_mode,
        moderation_mode: s.moderation_mode,
        governance_model: s.governance_model,
        plugin_policy: s.plugin_policy,
        features_enabled: s.features_enabled,
    }))
}

// ============================================================================
// Router
// ============================================================================

pub fn router(pool: PgPool) -> Router {
    Router::new()
        .route("/api/settings/public", get(get_public_settings))
        .route("/api/settings/setup/status", get(get_setup_status))
        .route("/api/settings/setup", post(complete_setup))
        .route("/api/settings/instance", get(get_instance_settings))
        .route("/api/settings/instance", patch(update_instance_settings))
        .route("/api/settings/communities/{community_id}", get(get_community_settings))
        .route("/api/settings/communities/{community_id}", patch(update_community_settings))
        .with_state(pool)
}