use std::path::Path;

use anyhow::Error;
use serde_json::Value;

use proxmox::api::{api, Router, SubdirMap};
use proxmox::list_subdirs_api_method;

use crate::{
    config,
    api2::types::{
        CHANGER_ID_SCHEMA,
        ScsiTapeChanger,
        TapeDeviceInfo,
        MtxStatusEntry,
        MtxEntryKind,
    },
    tape::{
        TAPE_STATUS_DIR,
        ElementStatus,
        OnlineStatusMap,
        Inventory,
        MediaStateDatabase,
        linux_tape_changer_list,
        mtx_status,
        mtx_status_to_online_set,
        mtx_transfer,
    },
};


#[api(
    input: {
        properties: {
            name: {
                schema: CHANGER_ID_SCHEMA,
            },
        },
    },
    returns: {
        description: "A status entry for each drive and slot.",
        type: Array,
        items: {
            type: MtxStatusEntry,
        },
    },
)]
/// Get tape changer status
pub fn get_status(name: String) -> Result<Vec<MtxStatusEntry>, Error> {

    let (config, _digest) = config::drive::config()?;

    let data: ScsiTapeChanger = config.lookup("changer", &name)?;

    let status = mtx_status(&data.path)?;

    let state_path = Path::new(TAPE_STATUS_DIR);
    let inventory = Inventory::load(state_path)?;

    let mut map = OnlineStatusMap::new(&config)?;
    let online_set = mtx_status_to_online_set(&status, &inventory);
    map.update_online_status(&name, online_set)?;

    let mut state_db = MediaStateDatabase::load(state_path)?;
    state_db.update_online_status(&map)?;

    let mut list = Vec::new();

    for (id, drive_status) in status.drives.iter().enumerate() {
        let entry = MtxStatusEntry {
            entry_kind: MtxEntryKind::Drive,
            entry_id: id as u64,
            changer_id: match &drive_status.status {
                ElementStatus::Empty => None,
                ElementStatus::Full => Some(String::new()),
                ElementStatus::VolumeTag(tag) => Some(tag.to_string()),
            },
            loaded_slot: drive_status.loaded_slot,
        };
        list.push(entry);
    }

    for (id, slot_status) in status.slots.iter().enumerate() {
        let entry = MtxStatusEntry {
            entry_kind: MtxEntryKind::Slot,
            entry_id: id as u64 + 1,
            changer_id: match &slot_status {
                ElementStatus::Empty => None,
                ElementStatus::Full => Some(String::new()),
                ElementStatus::VolumeTag(tag) => Some(tag.to_string()),
            },
            loaded_slot: None,
        };
        list.push(entry);
    }

    Ok(list)
}

#[api(
    input: {
        properties: {
            name: {
                schema: CHANGER_ID_SCHEMA,
            },
            from: {
                description: "Source slot number",
                minimum: 1,
            },
            to: {
                description: "Destination slot number",
                minimum: 1,
            },
        },
    },
)]
/// Transfers media from one slot to another
pub fn transfer(
    name: String,
    from: u64,
    to: u64,
) -> Result<(), Error> {

    let (config, _digest) = config::drive::config()?;

    let data: ScsiTapeChanger = config.lookup("changer", &name)?;

    mtx_transfer(&data.path, from, to)?;

    Ok(())
}

#[api(
    input: {
        properties: {},
    },
    returns: {
        description: "The list of autodetected tape changers.",
        type: Array,
        items: {
            type: TapeDeviceInfo,
        },
    },
)]
/// Scan for SCSI tape changers
pub fn scan_changers(_param: Value) -> Result<Vec<TapeDeviceInfo>, Error> {

    let list = linux_tape_changer_list();

    Ok(list)
}

const SUBDIRS: SubdirMap = &[
    (
        "scan",
        &Router::new()
            .get(&API_METHOD_SCAN_CHANGERS)
    ),
];

pub const ROUTER: Router = Router::new()
    .get(&list_subdirs_api_method!(SUBDIRS))
    .subdirs(SUBDIRS);