use axum::{
    Extension, Json,
    extract::{Path, State},
    http::StatusCode,
};
use crank_core::{
    AuditActor, AuditEvent, AuditEventId, AuditTarget, AuditTargetKind, PolicyAction,
    PolicyDecision, PolicyScope, SessionActor,
};
use serde::Deserialize;
use serde_json::{Value, json};
use time::OffsetDateTime;
use uuid::Uuid;

use crate::{
    auth::AuthenticatedSession,
    error::ApiError,
    service::{InvitationPayload, UpdateMembershipPayload},
    state::AppState,
};

#[derive(Deserialize)]
pub struct WorkspacePath {
    pub workspace_id: String,
}

#[derive(Deserialize)]
pub struct WorkspaceInvitationPath {
    pub workspace_id: String,
    pub invitation_id: String,
}

#[derive(Deserialize)]
pub struct WorkspaceMembershipPath {
    pub workspace_id: String,
    pub user_id: String,
}

pub async fn list_memberships(
    Path(path): Path<WorkspacePath>,
    State(state): State<AppState>,
) -> Result<Json<Value>, ApiError> {
    let items = state
        .service
        .list_memberships(&path.workspace_id.as_str().into())
        .await?;
    Ok(Json(json!({ "items": items })))
}

pub async fn update_membership(
    Path(path): Path<WorkspaceMembershipPath>,
    State(state): State<AppState>,
    Extension(session): Extension<AuthenticatedSession>,
    Json(payload): Json<UpdateMembershipPayload>,
) -> Result<Json<Value>, ApiError> {
    let workspace_id: crank_core::WorkspaceId = path.workspace_id.as_str().into();
    enforce_workspace_policy(
        &state,
        &session,
        &workspace_id,
        PolicyAction::WriteWorkspaceAccess,
    )?;
    let items = state
        .service
        .update_membership_role(
            &workspace_id,
            &session.user.id,
            &path.user_id.as_str().into(),
            payload,
        )
        .await?;
    record_access_audit(
        &state,
        &session,
        &workspace_id,
        "membership.role_updated",
        AuditTargetKind::Membership,
        path.user_id.clone(),
        json!({ "user_id": path.user_id }),
    )
    .await?;
    Ok(Json(json!({ "items": items })))
}

pub async fn delete_membership(
    Path(path): Path<WorkspaceMembershipPath>,
    State(state): State<AppState>,
    Extension(session): Extension<AuthenticatedSession>,
) -> Result<StatusCode, ApiError> {
    let workspace_id: crank_core::WorkspaceId = path.workspace_id.as_str().into();
    enforce_workspace_policy(
        &state,
        &session,
        &workspace_id,
        PolicyAction::WriteWorkspaceAccess,
    )?;
    state
        .service
        .remove_membership(
            &workspace_id,
            &session.user.id,
            &path.user_id.as_str().into(),
        )
        .await?;
    record_access_audit(
        &state,
        &session,
        &workspace_id,
        "membership.removed",
        AuditTargetKind::Membership,
        path.user_id.clone(),
        json!({ "user_id": path.user_id }),
    )
    .await?;
    Ok(StatusCode::NO_CONTENT)
}

pub async fn list_invitations(
    Path(path): Path<WorkspacePath>,
    State(state): State<AppState>,
) -> Result<Json<Value>, ApiError> {
    let items = state
        .service
        .list_invitations(&path.workspace_id.as_str().into())
        .await?;
    Ok(Json(json!({ "items": items })))
}

pub async fn create_invitation(
    Path(path): Path<WorkspacePath>,
    State(state): State<AppState>,
    Extension(session): Extension<AuthenticatedSession>,
    Json(payload): Json<InvitationPayload>,
) -> Result<Json<Value>, ApiError> {
    let workspace_id: crank_core::WorkspaceId = path.workspace_id.as_str().into();
    enforce_workspace_policy(
        &state,
        &session,
        &workspace_id,
        PolicyAction::WriteWorkspaceAccess,
    )?;
    let created = state
        .service
        .create_invitation(&workspace_id, payload)
        .await?;
    record_access_audit(
        &state,
        &session,
        &workspace_id,
        "invitation.created",
        AuditTargetKind::Invitation,
        created.invitation.invitation.id.as_str().to_owned(),
        json!({ "invitation_id": created.invitation.invitation.id.as_str() }),
    )
    .await?;
    Ok(Json(json!(created)))
}

pub async fn delete_invitation(
    Path(path): Path<WorkspaceInvitationPath>,
    State(state): State<AppState>,
    Extension(session): Extension<AuthenticatedSession>,
) -> Result<StatusCode, ApiError> {
    let workspace_id: crank_core::WorkspaceId = path.workspace_id.as_str().into();
    enforce_workspace_policy(
        &state,
        &session,
        &workspace_id,
        PolicyAction::WriteWorkspaceAccess,
    )?;
    state
        .service
        .delete_invitation(&workspace_id, &path.invitation_id.as_str().into())
        .await?;
    record_access_audit(
        &state,
        &session,
        &workspace_id,
        "invitation.deleted",
        AuditTargetKind::Invitation,
        path.invitation_id.clone(),
        json!({ "invitation_id": path.invitation_id }),
    )
    .await?;
    Ok(StatusCode::NO_CONTENT)
}

pub async fn export_workspace(
    Path(path): Path<WorkspacePath>,
    State(state): State<AppState>,
) -> Result<Json<Value>, ApiError> {
    let exported = state
        .service
        .export_workspace(&path.workspace_id.as_str().into())
        .await?;
    Ok(Json(json!(exported)))
}

pub async fn delete_workspace(
    Path(path): Path<WorkspacePath>,
    State(state): State<AppState>,
    Extension(session): Extension<AuthenticatedSession>,
) -> Result<StatusCode, ApiError> {
    let workspace_id: crank_core::WorkspaceId = path.workspace_id.as_str().into();
    enforce_workspace_policy(
        &state,
        &session,
        &workspace_id,
        PolicyAction::WriteWorkspace,
    )?;
    state
        .service
        .delete_workspace(&workspace_id, &session.user.id)
        .await?;
    record_access_audit(
        &state,
        &session,
        &workspace_id,
        "workspace.deleted",
        AuditTargetKind::Workspace,
        workspace_id.as_str().to_owned(),
        json!({ "workspace_id": workspace_id.as_str() }),
    )
    .await?;
    Ok(StatusCode::NO_CONTENT)
}

fn enforce_workspace_policy(
    state: &AppState,
    session: &AuthenticatedSession,
    workspace_id: &crank_core::WorkspaceId,
    action: PolicyAction,
) -> Result<(), ApiError> {
    let membership = session
        .memberships
        .iter()
        .find(|membership| membership.workspace.id == *workspace_id)
        .ok_or_else(|| ApiError::forbidden("workspace access denied"))?;
    let actor = SessionActor {
        user_id: session.user.id.clone(),
        workspace_id: workspace_id.clone(),
        role: membership.role,
    };

    match state.service.policy_engine().check(
        &actor,
        action,
        PolicyScope::Workspace(workspace_id.clone()),
    ) {
        PolicyDecision::Allow => Ok(()),
        PolicyDecision::Deny { reason } => Err(ApiError::forbidden(reason)),
    }
}

async fn record_access_audit(
    state: &AppState,
    session: &AuthenticatedSession,
    workspace_id: &crank_core::WorkspaceId,
    action: &str,
    target_kind: AuditTargetKind,
    target_id: String,
    payload: Value,
) -> Result<(), ApiError> {
    state
        .service
        .audit_sink()
        .record(AuditEvent {
            id: AuditEventId::new(format!("audit_{}", Uuid::now_v7().simple())),
            occurred_at: OffsetDateTime::now_utc(),
            actor: AuditActor {
                user_id: session.user.id.clone(),
                email: session.user.email.clone(),
                session_id: Some(session.session_id.clone()),
            },
            action: action.to_owned(),
            target: AuditTarget {
                workspace_id: workspace_id.clone(),
                kind: target_kind,
                id: target_id,
            },
            payload,
            source_ip: None,
            user_agent: None,
        })
        .await
        .map_err(|error| ApiError::internal(format!("failed to record audit event: {error}")))
}