//! The scene document: what the Studio GUI and agents edit (scene.json),
//! and the prefab catalog that describes each object type.

use serde::{Deserialize, Serialize};
use serde_json::{Map, Value};

fn one() -> u32 {
    1
}
fn is_zero(v: &f64) -> bool {
    *v == 0.0
}
fn is_false(v: &bool) -> bool {
    !*v
}

/// A scene document: placed objects plus parameter values.
#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
pub struct Doc {
    #[serde(default = "one")]
    pub version: u32,
    /// Values for the project parameters (override the manifest defaults).
    #[serde(default, skip_serializing_if = "Map::is_empty")]
    pub cfg: Map<String, Value>,
    #[serde(default)]
    pub objects: Vec<Object>,
}

/// One placed object. Its prefab (`kind`) draws it around (x, y, z), turned
/// by `rot` degrees (multiples of 90), in its own coordinates.
#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
pub struct Object {
    pub id: String,
    #[serde(rename = "type")]
    pub kind: String,
    #[serde(default, skip_serializing_if = "String::is_empty")]
    pub name: String,
    #[serde(default)]
    pub x: f64,
    #[serde(default)]
    pub y: f64,
    #[serde(default, skip_serializing_if = "is_zero")]
    pub z: f64,
    #[serde(default, skip_serializing_if = "is_zero")]
    pub rot: f64,
    /// Prefab properties; missing ones take the prefab defaults.
    #[serde(default, skip_serializing_if = "Map::is_empty")]
    pub props: Map<String, Value>,
    /// Tooltip text.
    #[serde(default, skip_serializing_if = "String::is_empty")]
    pub info: String,
    /// Label pinned above the object.
    #[serde(default, skip_serializing_if = "String::is_empty")]
    pub tag: String,
    /// Levels the object shows on (empty: all).
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub levels: Vec<String>,
    /// Outline or path in the object's own coordinates (areas, roads, fences).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub pts: Option<Vec<[f64; 2]>>,
    #[serde(default, skip_serializing_if = "is_false")]
    pub hidden: bool,
    #[serde(default, skip_serializing_if = "is_false")]
    pub locked: bool,
}

/// One editable property of a prefab.
#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
pub struct PropDef {
    pub key: String,
    /// float | int | bool | choice | text | material
    #[serde(rename = "type", default = "default_kind")]
    pub kind: String,
    /// Default value (`def` in Rhai, where `default` is a reserved word).
    #[serde(default, alias = "def")]
    pub default: Value,
    #[serde(default)]
    pub label: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub min: Option<f64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub max: Option<f64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub step: Option<f64>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub choices: Vec<String>,
    #[serde(default, skip_serializing_if = "String::is_empty")]
    pub help: String,
}

fn default_kind() -> String {
    "float".into()
}

/// An object type, read from the prefab's `meta_<type>()` function.
#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
pub struct PrefabMeta {
    #[serde(rename = "type", default)]
    pub kind: String,
    #[serde(default)]
    pub label: String,
    #[serde(default)]
    pub category: String,
    #[serde(default)]
    pub icon: String,
    #[serde(default)]
    pub help: String,
    /// How the Studio places it: "point" (click), "path" (click points).
    #[serde(default = "default_shape")]
    pub shape: String,
    #[serde(default)]
    pub props: Vec<PropDef>,
    /// Module the prefab comes from ("isokit/site", "lib/kiosk.rhai").
    #[serde(default)]
    pub source: String,
}

fn default_shape() -> String {
    "point".into()
}

impl PrefabMeta {
    pub fn prop(&self, key: &str) -> Option<&PropDef> {
        self.props.iter().find(|p| p.key == key)
    }

    /// Object props with the defaults filled in and numbers coerced to the
    /// declared types.
    pub fn resolve(&self, props: &Map<String, Value>) -> Map<String, Value> {
        let mut out = props.clone();
        for d in &self.props {
            let v = out.get(&d.key).cloned().unwrap_or_else(|| d.default.clone());
            let v = match (d.kind.as_str(), &v) {
                ("float", Value::Number(n)) => n.as_f64().map(Value::from).unwrap_or(v),
                ("float", Value::String(s)) => s.parse::<f64>().map(Value::from).unwrap_or(d.default.clone()),
                ("int", Value::Number(n)) => n.as_f64().map(|f| Value::from(f.round() as i64)).unwrap_or(v),
                ("int", Value::String(s)) => s.parse::<f64>().map(|f| Value::from(f.round() as i64)).unwrap_or(d.default.clone()),
                ("bool", Value::String(s)) => Value::Bool(matches!(s.as_str(), "true" | "1" | "yes" | "on")),
                ("bool", Value::Number(n)) => Value::Bool(n.as_f64().unwrap_or(0.0) != 0.0),
                _ => v,
            };
            out.insert(d.key.clone(), v);
        }
        out
    }
}

impl Doc {
    pub fn get(&self, id: &str) -> Option<&Object> {
        self.objects.iter().find(|o| o.id == id)
    }
    pub fn get_mut(&mut self, id: &str) -> Option<&mut Object> {
        self.objects.iter_mut().find(|o| o.id == id)
    }
    /// A free id: `base`, `base-2`, `base-3`, ...
    pub fn free_id(&self, base: &str) -> String {
        let base: String = base
            .chars()
            .map(|c| if c.is_ascii_alphanumeric() || c == '-' || c == '_' { c.to_ascii_lowercase() } else { '-' })
            .collect();
        let base = if base.is_empty() { "obj".to_string() } else { base };
        if self.get(&base).is_none() {
            return base;
        }
        (2..).map(|i| format!("{base}-{i}")).find(|id| self.get(id).is_none()).unwrap()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;

    #[test]
    fn object_round_trips_compactly() {
        let o: Object = serde_json::from_value(json!({"id": "t1", "type": "tree", "x": 3, "y": 4.5})).unwrap();
        assert_eq!(o.kind, "tree");
        let back = serde_json::to_value(&o).unwrap();
        assert_eq!(back, json!({"id": "t1", "type": "tree", "x": 3.0, "y": 4.5}));
    }

    #[test]
    fn defaults_and_coercion() {
        let m = PrefabMeta {
            props: vec![
                PropDef { key: "r".into(), kind: "float".into(), default: json!(1.5), ..Default::default() },
                PropDef { key: "n".into(), kind: "int".into(), default: json!(2), ..Default::default() },
                PropDef { key: "on".into(), kind: "bool".into(), default: json!(false), ..Default::default() },
            ],
            ..Default::default()
        };
        let p = m.resolve(json!({"n": "3.6", "on": "yes"}).as_object().unwrap());
        assert_eq!(p["r"], json!(1.5));
        assert_eq!(p["n"], json!(4));
        assert_eq!(p["on"], json!(true));
    }

    #[test]
    fn free_ids() {
        let mut d = Doc::default();
        assert_eq!(d.free_id("Tree"), "tree");
        d.objects.push(Object { id: "tree".into(), kind: "tree".into(), ..Default::default() });
        d.objects.push(Object { id: "tree-2".into(), kind: "tree".into(), ..Default::default() });
        assert_eq!(d.free_id("tree"), "tree-3");
    }
}