use std::{fmt, path::PathBuf};

use serde::{Deserialize, Serialize};

use crate::{path_serializer, project::ProjectNode};

/// Rojo-specific metadata that can be associated with an instance or a snapshot
/// of an instance.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct InstanceMetadata {
    /// Whether instances not present in the source should be ignored when
    /// live-syncing. This is useful when there are instances that Rojo does not
    /// manage.
    pub ignore_unknown_instances: bool,

    /// If a change occurs to this instance, the instigating source is what
    /// should be run through the snapshot functions to regenerate it.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub instigating_source: Option<InstigatingSource>,

    /// The paths that, when changed, could cause the function that generated
    /// this snapshot to generate a different snapshot. Paths should be included
    /// even if they don't exist, since the presence of a file can change the
    /// outcome of a snapshot function.
    ///
    /// For example, a file named foo.lua might have these relevant paths:
    /// - foo.lua
    /// - foo.meta.json (even if this file doesn't exist!)
    ///
    /// A directory named bar/ might have these:
    /// - bar/
    /// - bar/init.meta.json
    /// - bar/init.lua
    /// - bar/init.server.lua
    /// - bar/init.client.lua
    /// - bar/default.project.json
    ///
    /// This path is used to make sure that file changes update all instances
    /// that may need updates.
    // TODO: Change this to be a SmallVec for performance in common cases?
    #[serde(serialize_with = "path_serializer::serialize_vec_absolute")]
    pub relevant_paths: Vec<PathBuf>,
}

impl Default for InstanceMetadata {
    fn default() -> Self {
        InstanceMetadata {
            ignore_unknown_instances: false,
            instigating_source: None,
            relevant_paths: Vec::new(),
        }
    }
}

#[derive(Clone, PartialEq, Serialize, Deserialize)]
pub enum InstigatingSource {
    Path(#[serde(serialize_with = "path_serializer::serialize_absolute")] PathBuf),
    ProjectNode(String, ProjectNode),
}

impl fmt::Debug for InstigatingSource {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            InstigatingSource::Path(path) => write!(formatter, "Path({})", path.display()),
            InstigatingSource::ProjectNode(name, node) => {
                write!(formatter, "ProjectNode({}: {:?}", name, node)
            }
        }
    }
}

impl From<PathBuf> for InstigatingSource {
    fn from(path: PathBuf) -> Self {
        InstigatingSource::Path(path)
    }
}