/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

use crate::GenApiError;

use super::{
    interface::{INode, IRegister, IString},
    node_base::{NodeAttributeBase, NodeBase},
    register_base::RegisterBase,
    store::{CacheStore, NodeStore, ValueStore},
    Device, GenApiResult, ValueCtxt,
};

#[derive(Debug, Clone)]
pub struct StringRegNode {
    pub(crate) attr_base: NodeAttributeBase,
    pub(crate) register_base: RegisterBase,
}

impl StringRegNode {
    #[must_use]
    pub fn register_base(&self) -> &RegisterBase {
        &self.register_base
    }
}

impl INode for StringRegNode {
    fn node_base(&self) -> NodeBase {
        let elem_base = &self.register_base.elem_base;
        NodeBase::new(&self.attr_base, elem_base)
    }

    fn streamable(&self) -> bool {
        self.register_base().streamable()
    }
}

impl IString for StringRegNode {
    #[tracing::instrument(skip(self, device, store, cx),
                          level = "trace",
                          fields(node = store.name_by_id(self.node_base().id()).unwrap()))]
    fn value<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<String> {
        let nid = self.node_base().id();
        let reg = self.register_base();
        reg.with_cache_or_read(nid, device, store, cx, |data| {
            let str_end = data.iter().position(|b| *b == 0).unwrap_or(data.len());
            Ok(String::from_utf8_lossy(&data[..str_end]).to_string())
        })
    }

    #[tracing::instrument(skip(self, device, store, cx),
                          level = "trace",
                          fields(node = store.name_by_id(self.node_base().id()).unwrap()))]
    fn set_value<T: ValueStore, U: CacheStore>(
        &self,
        value: String,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<()> {
        let max_length = self.max_length(device, store, cx)? as usize;
        if !value.is_ascii() {
            return Err(GenApiError::invalid_data(
                "the data must be an ascii string".into(),
            ));
        }
        if value.len() > max_length {
            return Err(GenApiError::invalid_data(
                "the data length exceeds the maximum length allowed by the node.".into(),
            ));
        }

        let nid = self.node_base().id();
        cx.invalidate_cache_by(nid);

        let reg = self.register_base();
        let mut bytes = value.into_bytes();
        bytes.resize(max_length, 0);
        reg.write_and_cache(nid, &bytes, device, store, cx)
    }

    #[tracing::instrument(skip(self, device, store, cx),
                          level = "trace",
                          fields(node = store.name_by_id(self.node_base().id()).unwrap()))]
    fn max_length<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<i64> {
        self.length(device, store, cx)
    }

    #[tracing::instrument(skip(self, device, store, cx),
                          level = "trace",
                          fields(node = store.name_by_id(self.node_base().id()).unwrap()))]
    fn is_readable<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<bool> {
        self.register_base().is_readable(device, store, cx)
    }

    #[tracing::instrument(skip(self, device, store, cx),
                          level = "trace",
                          fields(node = store.name_by_id(self.node_base().id()).unwrap()))]
    fn is_writable<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<bool> {
        self.register_base().is_writable(device, store, cx)
    }
}

impl IRegister for StringRegNode {
    fn read<T: ValueStore, U: CacheStore>(
        &self,
        buf: &mut [u8],
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<()> {
        let address = self.address(device, store, cx)?;
        let length = self.length(device, store, cx)?;
        self.register_base().read_and_cache(
            self.node_base().id(),
            address,
            length,
            buf,
            device,
            store,
            cx,
        )
    }

    fn write<T: ValueStore, U: CacheStore>(
        &self,
        buf: &[u8],
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<()> {
        self.register_base()
            .write_and_cache(self.node_base().id(), buf, device, store, cx)
    }

    fn address<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<i64> {
        self.register_base().address(device, store, cx)
    }

    fn length<T: ValueStore, U: CacheStore>(
        &self,
        device: &mut impl Device,
        store: &impl NodeStore,
        cx: &mut ValueCtxt<T, U>,
    ) -> GenApiResult<i64> {
        self.register_base().length(device, store, cx)
    }
}