use std::path::Path as FsPath;

use uuid::Uuid;

use crate::error::{AppError, AppResult};
use crate::models::{Document, DocumentAsset, DocumentAssetObject, DocumentVersion};
use crate::state::AppState;
use crate::utils::time::to_iso;

use super::{
    DocumentAssetDetailResponse, DocumentAssetObjectResponse, DocumentAssetResponse,
    DocumentVersionResponse,
};

pub fn build_download_path(
    state: &AppState,
    document: &Document,
    user_id: Uuid,
) -> AppResult<String> {
    state
        .jwt
        .generate_download_token(document.id, user_id, document.tenant_id)
        .map(|token| format!("/download/{token}"))
        .map_err(|err| AppError::internal(format!("failed to generate download token: {err}")))
}

pub fn to_version_response(
    version: DocumentVersion,
    include_operations_summary: bool,
) -> DocumentVersionResponse {
    DocumentVersionResponse {
        id: version.id,
        version_number: version.version_number,
        s3_key: version.s3_key,
        size_bytes: version.size_bytes,
        checksum: version.checksum,
        created_at: to_iso(version.created_at),
        metadata: version.metadata,
        operations_summary: if include_operations_summary {
            Some(version.operations_summary)
        } else {
            None
        },
    }
}

pub fn to_asset_summary(asset: DocumentAsset) -> DocumentAssetResponse {
    DocumentAssetResponse {
        id: asset.id,
        asset_type: asset.asset_type,
        mime_type: asset.mime_type,
        metadata: asset.metadata,
        cardinality: asset.cardinality,
    }
}

pub fn to_asset_detail_response(
    asset: DocumentAsset,
    objects: Vec<DocumentAssetObjectResponse>,
) -> DocumentAssetDetailResponse {
    DocumentAssetDetailResponse {
        id: asset.id,
        asset_type: asset.asset_type,
        mime_type: asset.mime_type,
        metadata: asset.metadata,
        created_at: to_iso(asset.created_at),
        cardinality: asset.cardinality,
        objects,
    }
}

pub fn to_asset_object_response(
    object: DocumentAssetObject,
    url: Option<String>,
    expires_at: Option<i64>,
) -> DocumentAssetObjectResponse {
    DocumentAssetObjectResponse {
        id: object.id,
        ordinal: object.ordinal,
        metadata: object.metadata,
        url,
        expires_at,
    }
}

pub fn derive_document_title(original: &str) -> String {
    let trimmed = original.trim();
    if trimmed.is_empty() {
        return "Document".to_string();
    }

    let stem = FsPath::new(trimmed)
        .file_stem()
        .and_then(|s| s.to_str())
        .map(|s| s.trim())
        .filter(|s| !s.is_empty())
        .map(|s| s.to_string());

    stem.unwrap_or_else(|| trimmed.to_string())
}

pub fn filename_with_retained_extension(title: &str, current_filename: &str) -> String {
    let extension = FsPath::new(current_filename)
        .extension()
        .and_then(|ext| ext.to_str());

    if let Some(ext) = extension {
        if title
            .rsplit_once('.')
            .map(|(_, existing_ext)| existing_ext.eq_ignore_ascii_case(ext))
            .unwrap_or(false)
        {
            title.to_string()
        } else {
            format!("{title}.{ext}")
        }
    } else {
        title.to_string()
    }
}