use crate::discover_external_memory_files;
use crate::memory_import::memory_versions;
use crate::memory_import::projects_needing_import;
use crate::memory_import::resources_root;
use crate::model::ExternalAgentConfigMigrationItem;
use crate::model::ExternalAgentConfigMigrationItemType;
use crate::model::MigrationDetails;
use codex_protocol::MemoryVersion;
use std::collections::BTreeSet;
use std::io;
use std::path::Path;

pub(super) fn detect(
    codex_home: &Path,
    external_agent_home: &Path,
    selection: MemoryVersion,
) -> io::Result<Option<ExternalAgentConfigMigrationItem>> {
    let memory_files = discover_external_memory_files(external_agent_home)?;
    let mut memory = BTreeSet::new();
    for version in memory_versions(codex_home, selection)? {
        memory.extend(projects_needing_import(
            &codex_home.join(version.directory_name()),
            &memory_files,
        )?);
    }
    if memory.is_empty() {
        return Ok(None);
    }

    Ok(Some(ExternalAgentConfigMigrationItem {
        item_type: ExternalAgentConfigMigrationItemType::Memory,
        description: format!(
            "Import memory files from {} to {}",
            external_agent_home.join("projects").display(),
            resources_root(&codex_home.join(MemoryVersion::V2.directory_name())).display()
        ),
        cwd: None,
        details: Some(MigrationDetails {
            memory: memory.into_iter().collect(),
            ..Default::default()
        }),
    }))
}