//! Profile sharing (Phase B).
//!
//! Implements the X25519 envelope: an owner wraps a profile DEK to a
//! recipient's identity public key via ECDH, storing the opaque wrapped blob
//! keyed by (profileId, recipientUserId). Recipients unwrap with their own
//! identity private key. The server never sees the profile DEK.
//!
//! Also provides `authorize_profile_read` — the share-gate used by the data
//! handlers (medications, appointments, health stats) to admit recipients.

use axum::{
    extract::{Extension, Path, Query, State},
    http::StatusCode,
    Json,
};
use mongodb::bson::{oid::ObjectId, DateTime};
use serde::{Deserialize, Serialize};

use crate::{
    auth::jwt::Claims,
    config::AppState,
    models::profile::ProfileRepository,
    models::profile_share::{ProfileShare, ProfileShareRepository},
};

fn profile_repo(state: &AppState) -> ProfileRepository {
    ProfileRepository::new(state.db.get_database().collection("profiles"))
}

fn share_repo(state: &AppState) -> ProfileShareRepository {
    ProfileShareRepository::new(state.db.get_database().collection("profile_shares"))
}

/// The shared profile as seen by the recipient — the profile's metadata
/// (display name blob, kind, relationship) plus the per-share ECDH-wrapped DEK
/// the recipient unwraps with their identity private key. The server returns
/// the wrapped DEK from the share record verbatim and cannot read it.
#[derive(Debug, Serialize)]
pub struct SharedProfileResponse {
    pub profile_id: String,
    pub owner_account_id: String,
    pub name_data: String,
    pub name_iv: String,
    pub kind: String,
    pub relationship: String,
    /// Per-share ephemeral X25519 public key (base64 raw). The recipient
    /// combines it with their identity private key to derive the wrap key.
    pub ephemeral_public_key: String,
    /// Profile DEK wrapped under the ECDH-derived key (opaque).
    pub wrapped_profile_dek: String,
    pub wrapped_profile_dek_iv: String,
    pub permissions: Vec<String>,
    pub created_at: DateTime,
}

/// A share as listed by the owner (no wrapped DEK on this view — it's only
/// useful to the recipient; the owner already has the profile DEK directly).
#[derive(Debug, Serialize)]
pub struct ShareListingResponse {
    pub profile_id: String,
    pub recipient_user_id: String,
    pub recipient_email: String,
    pub permissions: Vec<String>,
    pub created_at: DateTime,
    pub active: bool,
}

// ---------------------------------------------------------------------------
// Share-gate: resolve the owner userId for a profile the caller may read.
// Used by the data handlers to admit recipients.
// ---------------------------------------------------------------------------

/// If the caller (claims.sub) owns the profile, returns Ok(owner_user_id).
/// Otherwise checks for an active share; if present, returns Ok(owner_user_id)
/// (the profile's owner — recipients read "as the owner" for that profile).
/// Returns Err(404 response) if the caller has no read access.
pub async fn authorize_profile_read(
    state: &AppState,
    claims: &Claims,
    profile_id: &str,
) -> Result<String, (StatusCode, Json<serde_json::Value>)> {
    let profiles = profile_repo(state);
    // Owner path.
    if let Ok(Some(owned)) = profiles
        .find_by_profile_id_owned(profile_id, &claims.sub)
        .await
    {
        return Ok(owned.owner_account_id);
    }
    // Recipient path: an active (unexpired, not-revoked) share for this pair.
    let shares = share_repo(state);
    match shares.find_active(profile_id, &claims.sub).await {
        Ok(Some(share)) => Ok(share.owner_user_id),
        Ok(None) => Err((
            StatusCode::NOT_FOUND,
            Json(serde_json::json!({ "error": "profile not found" })),
        )),
        Err(e) => {
            tracing::error!("Share lookup failed for {}: {}", profile_id, e);
            Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ))
        }
    }
}

// ---------------------------------------------------------------------------
// POST /api/profiles/:id/shares — owner shares a profile to a recipient.
// ---------------------------------------------------------------------------

#[derive(Debug, Deserialize)]
pub struct CreateShareRequest {
    /// The recipient, identified by email.
    pub recipient_email: String,
    /// Ephemeral X25519 public key (base64 raw) generated by the owner's
    /// client for this share.
    pub ephemeral_public_key: String,
    /// Profile DEK wrapped (client-side, via ECDH) to the recipient. Opaque.
    pub wrapped_profile_dek: String,
    pub wrapped_profile_dek_iv: String,
    #[serde(default = "default_read_permissions")]
    pub permissions: Vec<String>,
    /// Optional RFC-3339 expiry; null/absent = never expires.
    pub expires_at: Option<String>,
}

fn default_read_permissions() -> Vec<String> {
    vec!["read".to_string()]
}

pub async fn create_share(
    State(state): State<AppState>,
    Extension(claims): Extension<Claims>,
    Path(profile_id): Path<String>,
    Json(req): Json<CreateShareRequest>,
) -> Result<(StatusCode, Json<ShareListingResponse>), (StatusCode, Json<serde_json::Value>)> {
    // Verify the caller owns the profile.
    let profiles = profile_repo(&state);
    let owner = match profiles
        .find_by_profile_id_owned(&profile_id, &claims.sub)
        .await
    {
        Ok(Some(p)) => p.owner_account_id,
        Ok(None) => {
            return Err((
                StatusCode::NOT_FOUND,
                Json(serde_json::json!({ "error": "profile not found" })),
            ));
        }
        Err(e) => {
            tracing::error!("Profile lookup in create_share failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    };

    // Resolve recipient by email.
    let recipient = match state.db.find_user_by_email(&req.recipient_email).await {
        Ok(Some(u)) => u,
        Ok(None) => {
            return Err((
                StatusCode::NOT_FOUND,
                Json(serde_json::json!({ "error": "recipient not found" })),
            ));
        }
        Err(e) => {
            tracing::error!("Recipient lookup failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    };
    let recipient_id = match recipient.id {
        Some(id) => id.to_string(),
        None => {
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "invalid recipient state" })),
            ));
        }
    };
    // Can't share to an account without an identity public key (pre-A1).
    if recipient
        .identity_public_key
        .as_deref()
        .unwrap_or("")
        .is_empty()
    {
        return Err((
            StatusCode::NOT_FOUND,
            Json(serde_json::json!({
                "error": "recipient has no identity public key (account predates the keypair feature)"
            })),
        ));
    }
    // Don't share to yourself.
    if recipient_id == claims.sub {
        return Err((
            StatusCode::BAD_REQUEST,
            Json(serde_json::json!({ "error": "cannot share a profile with yourself" })),
        ));
    }

    let expires_at = match req.expires_at.as_deref() {
        Some(s) => match DateTime::parse_rfc3339_str(s) {
            Ok(dt) => Some(dt),
            Err(_) => {
                return Err((
                    StatusCode::BAD_REQUEST,
                    Json(serde_json::json!({ "error": "invalid expires_at (expected RFC 3339)" })),
                ));
            }
        },
        None => None,
    };

    let now = DateTime::now();
    let share = ProfileShare {
        id: None,
        profile_id: profile_id.clone(),
        owner_user_id: owner.clone(),
        recipient_user_id: recipient_id.clone(),
        ephemeral_public_key: req.ephemeral_public_key,
        wrapped_profile_dek: req.wrapped_profile_dek,
        wrapped_profile_dek_iv: req.wrapped_profile_dek_iv,
        permissions: req.permissions.clone(),
        expires_at,
        created_at: now,
        active: true,
    };

    let shares = share_repo(&state);
    if let Err(e) = shares.upsert(&share).await {
        tracing::error!("Share create failed: {}", e);
        return Err((
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(serde_json::json!({ "error": "database error" })),
        ));
    }

    Ok((
        StatusCode::CREATED,
        Json(ShareListingResponse {
            profile_id,
            recipient_user_id: recipient_id,
            recipient_email: req.recipient_email,
            permissions: req.permissions,
            created_at: now,
            active: true,
        }),
    ))
}

// ---------------------------------------------------------------------------
// GET /api/profiles/:id/shares — owner lists who they've shared a profile with.
// ---------------------------------------------------------------------------

pub async fn list_shares(
    State(state): State<AppState>,
    Extension(claims): Extension<Claims>,
    Path(profile_id): Path<String>,
) -> Result<Json<Vec<ShareListingResponse>>, (StatusCode, Json<serde_json::Value>)> {
    // Owner-only: confirm ownership.
    let profiles = profile_repo(&state);
    match profiles
        .find_by_profile_id_owned(&profile_id, &claims.sub)
        .await
    {
        Ok(Some(_)) => {}
        Ok(None) => {
            return Err((
                StatusCode::NOT_FOUND,
                Json(serde_json::json!({ "error": "profile not found" })),
            ));
        }
        Err(e) => {
            tracing::error!("Profile lookup in list_shares failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    }

    let shares = share_repo(&state);
    let rows = match shares.find_for_profile(&profile_id).await {
        Ok(rows) => rows,
        Err(e) => {
            tracing::error!("Share list failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    };

    // Resolve each recipient's email for display.
    let mut out = Vec::with_capacity(rows.len());
    for s in rows {
        let email = match ObjectId::parse_str(&s.recipient_user_id) {
            Ok(oid) => match state.db.find_user_by_id(&oid).await {
                Ok(Some(u)) => u.email,
                _ => String::new(),
            },
            Err(_) => String::new(),
        };
        out.push(ShareListingResponse {
            profile_id: s.profile_id,
            recipient_user_id: s.recipient_user_id,
            recipient_email: email,
            permissions: s.permissions,
            created_at: s.created_at,
            active: s.active,
        });
    }
    Ok(Json(out))
}

// ---------------------------------------------------------------------------
// DELETE /api/profiles/:id/shares/:recipient — soft revoke (hard delete).
// ---------------------------------------------------------------------------

pub async fn delete_share(
    State(state): State<AppState>,
    Extension(claims): Extension<Claims>,
    Path((profile_id, recipient_user_id)): Path<(String, String)>,
) -> Result<StatusCode, (StatusCode, Json<serde_json::Value>)> {
    // Owner-only: confirm ownership.
    let profiles = profile_repo(&state);
    match profiles
        .find_by_profile_id_owned(&profile_id, &claims.sub)
        .await
    {
        Ok(Some(_)) => {}
        Ok(None) => {
            return Err((
                StatusCode::NOT_FOUND,
                Json(serde_json::json!({ "error": "profile not found" })),
            ));
        }
        Err(e) => {
            tracing::error!("Profile lookup in delete_share failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    }

    let shares = share_repo(&state);
    match shares.delete(&profile_id, &recipient_user_id).await {
        Ok(true) => Ok(StatusCode::NO_CONTENT),
        Ok(false) => Err((
            StatusCode::NOT_FOUND,
            Json(serde_json::json!({ "error": "share not found" })),
        )),
        Err(e) => {
            tracing::error!("Share delete failed: {}", e);
            Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ))
        }
    }
}

// ---------------------------------------------------------------------------
// GET /api/profiles/shared-with-me — recipient lists profiles shared with them.
// ---------------------------------------------------------------------------

pub async fn list_shared_with_me(
    State(state): State<AppState>,
    Extension(claims): Extension<Claims>,
) -> Result<Json<Vec<SharedProfileResponse>>, (StatusCode, Json<serde_json::Value>)> {
    let shares = share_repo(&state);
    let my_shares = match shares.find_for_recipient(&claims.sub).await {
        Ok(rows) => rows,
        Err(e) => {
            tracing::error!("shared-with-me list failed: {}", e);
            return Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ));
        }
    };

    // Join each share with its profile's metadata. Only return shares for
    // profiles that still exist and are still active/unexpired (find_active
    // semantics, re-checked here to avoid listing a just-expired share).
    let profiles = profile_repo(&state);
    let mut out = Vec::with_capacity(my_shares.len());
    for s in my_shares {
        // Skip expired/inactive — find_for_recipient returns all rows; filter
        // to currently-usable ones for the recipient's view.
        if !s.active {
            continue;
        }
        if let Some(exp) = s.expires_at {
            if exp <= DateTime::now() {
                continue;
            }
        }
        let profile = match profiles.find_by_profile_id(&s.profile_id).await {
            Ok(Some(p)) => p,
            _ => continue, // profile deleted; skip silently
        };
        out.push(SharedProfileResponse {
            profile_id: profile.profile_id,
            owner_account_id: profile.owner_account_id,
            name_data: profile.name,
            name_iv: profile.name_iv,
            kind: profile.kind,
            relationship: profile.relationship,
            ephemeral_public_key: s.ephemeral_public_key,
            wrapped_profile_dek: s.wrapped_profile_dek,
            wrapped_profile_dek_iv: s.wrapped_profile_dek_iv,
            permissions: s.permissions,
            created_at: s.created_at,
        });
    }
    Ok(Json(out))
}

// ---------------------------------------------------------------------------
// GET /api/profiles/:id — extend the existing profile GET to admit recipients.
// This stands in for "the recipient can fetch one shared profile's metadata".
// Implemented here so the share-aware logic lives with the share code.
// ---------------------------------------------------------------------------

/// Fetch a single profile's metadata, admitting both owner and share-recipient.
/// Returns the owner's-view `ProfileResponse` shape (the wrapped profile DEK
/// there is account-wrapped — recipients ignore it and use the share's
/// ECDH-wrapped DEK from /profiles/shared-with-me instead).
pub async fn get_profile_shared_aware(
    State(state): State<AppState>,
    Extension(claims): Extension<Claims>,
    Path(profile_id): Path<String>,
) -> Result<Json<ProfileResponse>, (StatusCode, Json<serde_json::Value>)> {
    // authorize_profile_read admits owner or active-share recipient.
    let _owner = authorize_profile_read(&state, &claims, &profile_id).await?;
    let profiles = profile_repo(&state);
    match profiles.find_by_profile_id(&profile_id).await {
        Ok(Some(p)) => Ok(Json(ProfileResponse::from(p))),
        Ok(None) => Err((
            StatusCode::NOT_FOUND,
            Json(serde_json::json!({ "error": "profile not found" })),
        )),
        Err(e) => {
            tracing::error!("Profile fetch failed: {}", e);
            Err((
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(serde_json::json!({ "error": "database error" })),
            ))
        }
    }
}

// Re-export ProfileResponse from the profile handlers for the shared-aware GET.
pub use crate::handlers::profile::ProfileResponse;

// ---------------------------------------------------------------------------
// GET /api/users/public-key — look up a recipient's identity public key.
// Public (no auth) — public keys are not secret.
// ---------------------------------------------------------------------------

#[derive(Debug, Deserialize)]
pub struct PublicKeyQuery {
    pub email: String,
}

#[derive(Debug, Serialize)]
pub struct PublicKeyResponse {
    pub user_id: String,
    pub identity_public_key: String,
}

pub async fn get_public_key(
    State(state): State<AppState>,
    Query(q): Query<PublicKeyQuery>,
) -> Result<Json<PublicKeyResponse>, (StatusCode, Json<serde_json::Value>)> {
    let user = match state.db.find_user_by_email(&q.email).await {
        Ok(Some(u)) => u,
        Ok(None) | Err(_) => {
            // Don't leak whether the email exists.
            return Err((
                StatusCode::NOT_FOUND,
                Json(serde_json::json!({ "error": "no public key for this address" })),
            ));
        }
    };
    let user_id = user
        .id
        .ok_or((
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(serde_json::json!({ "error": "invalid user state" })),
        ))?
        .to_string();
    let pk = user.identity_public_key.unwrap_or_default();
    if pk.is_empty() {
        return Err((
            StatusCode::NOT_FOUND,
            Json(serde_json::json!({ "error": "no public key for this address" })),
        ));
    }
    Ok(Json(PublicKeyResponse {
        user_id,
        identity_public_key: pk,
    }))
}