fast-mvt 0.6.0

use std::fmt;

use usize_cast::IntoUsize;

use crate::generated::vector_tile::tile as proto_tile;
use crate::{MvtError, MvtResult, MvtValue};

#[derive(Debug, Clone)]
pub struct MvtPropertyIter<'a> {
    keys: &'a [&'a str],
    values: &'a [proto_tile::ValueView<'a>],
    tags: std::slice::Chunks<'a, u32>,
}

impl<'a> MvtPropertyIter<'a> {
    pub(crate) fn new(
        keys: &'a [&'a str],
        values: &'a [proto_tile::ValueView<'a>],
        tags: std::slice::Chunks<'a, u32>,
    ) -> Self {
        Self { keys, values, tags }
    }
}

impl<'a> Iterator for MvtPropertyIter<'a> {
    type Item = MvtResult<(&'a str, MvtValueRef<'a>)>;

    fn next(&mut self) -> Option<Self::Item> {
        let pair = self.tags.next()?;
        let [key_idx, value_idx] = pair else {
            return Some(Err(MvtError::InvalidTagsLength(pair.len())));
        };
        let key = match self.keys.get((*key_idx).into_usize()) {
            Some(key) => *key,
            None => return Some(Err(MvtError::InvalidKeyIndex(*key_idx))),
        };
        let value = match self.values.get((*value_idx).into_usize()) {
            Some(value) => value_ref(value),
            None => return Some(Err(MvtError::InvalidValueIndex(*value_idx))),
        };
        Some(Ok((key, value)))
    }
}

#[derive(Copy, Clone, PartialEq)]
pub enum MvtValueRef<'a> {
    String(&'a str),
    Float(f32),
    Double(f64),
    Int(i64),
    UInt(u64),
    SInt(i64),
    Bool(bool),
    Null,
}

impl MvtValueRef<'_> {
    #[must_use]
    pub fn into_owned(self) -> MvtValue {
        match self {
            Self::String(value) => MvtValue::String(value.to_string()),
            Self::Float(value) => MvtValue::Float(value),
            Self::Double(value) => MvtValue::Double(value),
            Self::Int(value) => MvtValue::Int(value),
            Self::UInt(value) => MvtValue::UInt(value),
            Self::SInt(value) => MvtValue::SInt(value),
            Self::Bool(value) => MvtValue::Bool(value),
            Self::Null => MvtValue::Null,
        }
    }
}

impl fmt::Debug for MvtValueRef<'_> {
    /// Renders the bare textual value (strings quoted)
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match *self {
            MvtValueRef::String(value) => write!(f, "{value:?}"),
            MvtValueRef::Float(value) => write!(f, "{value} (float)"),
            MvtValueRef::Double(value) => write!(f, "{value} (double)"),
            MvtValueRef::Int(value) => write!(f, "{value} (int)"),
            MvtValueRef::SInt(value) => write!(f, "{value} (sint)"),
            MvtValueRef::UInt(value) => write!(f, "{value} (uint)"),
            MvtValueRef::Bool(value) => write!(f, "{value} (bool)"),
            MvtValueRef::Null => f.write_str("null"),
        }
    }
}

pub(crate) fn value_ref<'a>(value: &'a proto_tile::ValueView<'a>) -> MvtValueRef<'a> {
    if let Some(value) = value.string_value {
        MvtValueRef::String(value)
    } else if let Some(value) = value.float_value {
        MvtValueRef::Float(value)
    } else if let Some(value) = value.double_value {
        MvtValueRef::Double(value)
    } else if let Some(value) = value.int_value {
        MvtValueRef::Int(value)
    } else if let Some(value) = value.uint_value {
        MvtValueRef::UInt(value)
    } else if let Some(value) = value.sint_value {
        MvtValueRef::SInt(value)
    } else if let Some(value) = value.bool_value {
        MvtValueRef::Bool(value)
    } else {
        MvtValueRef::Null
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::MvtReaderRef;
    use crate::reader::tests::{encode_layer, first_feature};

    #[test]
    fn value_ref_debug_renders_bare_values() {
        insta::assert_debug_snapshot!(MvtValueRef::String("x"), @r#""x""#);
        insta::assert_debug_snapshot!(MvtValueRef::Float(1.25), @"1.25 (float)");
        insta::assert_debug_snapshot!(MvtValueRef::Double(2.5), @"2.5 (double)");
        insta::assert_debug_snapshot!(MvtValueRef::Int(-3), @"-3 (int)");
        insta::assert_debug_snapshot!(MvtValueRef::UInt(4), @"4 (uint)");
        insta::assert_debug_snapshot!(MvtValueRef::SInt(-5), @"-5 (sint)");
        insta::assert_debug_snapshot!(MvtValueRef::Bool(true), @"true (bool)");
        insta::assert_debug_snapshot!(MvtValueRef::Null, @"null");
    }

    #[test]
    fn value_ref_into_owned_covers_every_variant() {
        assert_eq!(
            MvtValueRef::String("x").into_owned(),
            MvtValue::String("x".into())
        );
        assert_eq!(MvtValueRef::Float(1.25).into_owned(), MvtValue::Float(1.25));
        assert_eq!(MvtValueRef::Double(2.5).into_owned(), MvtValue::Double(2.5));
        assert_eq!(MvtValueRef::Int(-3).into_owned(), MvtValue::Int(-3));
        assert_eq!(MvtValueRef::UInt(4).into_owned(), MvtValue::UInt(4));
        assert_eq!(MvtValueRef::SInt(-5).into_owned(), MvtValue::SInt(-5));
        assert_eq!(MvtValueRef::Bool(true).into_owned(), MvtValue::Bool(true));
        assert_eq!(MvtValueRef::Null.into_owned(), MvtValue::Null);
    }

    #[test]
    fn property_iterator_reports_malformed_tags() {
        let layer = proto_tile::Layer {
            version: 2,
            name: "tags".into(),
            keys: vec!["k".into()],
            values: vec![proto_tile::Value::default()],
            ..Default::default()
        };

        for (tags, expected) in [
            (vec![0], "invalid feature tags length: 1"),
            (vec![1, 0], "invalid key index 1"),
            (vec![0, 1], "invalid value index 1"),
        ] {
            let feature = proto_tile::Feature {
                tags,
                ..Default::default()
            };
            let mut layer = layer.clone();
            layer.features = vec![feature];
            let bytes = encode_layer(layer);
            let reader = MvtReaderRef::new(&bytes).unwrap();
            let err = first_feature(&reader)
                .properties()
                .next()
                .unwrap()
                .unwrap_err();
            assert_eq!(err.to_string(), expected);
        }
    }
}