bzr 0.2.0

use std::borrow::Cow;

use serde::Deserialize;

use super::BugzillaClient;
use crate::error::{BzrError, Result};
use crate::types::FieldValue;

/// Known field name aliases mapped to their Bugzilla API internal names.
/// Sorted alphabetically by alias.
///
/// These aliases cannot shadow real Bugzilla field names because Bugzilla
/// requires custom fields to use the `cf_` prefix (e.g. `cf_status`), and
/// the built-in fields have fixed names (e.g. `bug_status`, `priority`).
/// No real field can have a bare name like `status` or `severity`, so eager
/// resolution is always safe.
pub(crate) const FIELD_ALIASES: &[(&str, &str)] = &[
    ("file_loc", "bug_file_loc"),
    ("group", "bug_group"),
    ("id", "bug_id"),
    ("severity", "bug_severity"),
    ("status", "bug_status"),
    ("type", "bug_type"),
];

#[derive(Deserialize)]
struct FieldBugResponse {
    fields: Vec<FieldEntry>,
}

#[derive(Deserialize)]
struct FieldEntry {
    values: Vec<FieldValue>,
}

fn resolve_field_alias(name: &str) -> Cow<'_, str> {
    let lower = name.to_ascii_lowercase();
    for &(alias, api_name) in FIELD_ALIASES {
        if lower == alias {
            return Cow::Borrowed(api_name);
        }
    }
    // Unknown fields pass through unchanged; only known aliases are normalized.
    Cow::Borrowed(name)
}

impl BugzillaClient {
    /// Fetch legal values for a bug field.
    ///
    /// Returns `NotFound` when the server does not recognize the field name
    /// (empty `fields` array). An empty `Vec` means the field exists but has
    /// no legal values.
    pub async fn get_field_values(&self, field_name: &str) -> Result<Vec<FieldValue>> {
        let resolved = resolve_field_alias(field_name);
        let data: FieldBugResponse = self.get_json(&format!("field/bug/{resolved}")).await?;
        let field = data
            .fields
            .into_iter()
            .next()
            .ok_or_else(|| BzrError::NotFound {
                resource: "field",
                id: field_name.to_string(),
            })?;
        Ok(field.values)
    }
}

#[cfg(test)]
#[expect(clippy::unwrap_used)]
mod tests {
    use wiremock::matchers::{method, path};
    use wiremock::{Mock, MockServer, ResponseTemplate};

    use crate::client::test_helpers::test_client;
    use crate::error::BzrError;

    #[test]
    fn resolve_field_alias_maps_status() {
        assert_eq!(super::resolve_field_alias("status").as_ref(), "bug_status");
    }

    #[test]
    fn resolve_field_alias_maps_severity() {
        assert_eq!(
            super::resolve_field_alias("severity").as_ref(),
            "bug_severity"
        );
    }

    #[test]
    fn resolve_field_alias_maps_id() {
        assert_eq!(super::resolve_field_alias("id").as_ref(), "bug_id");
    }

    #[test]
    fn resolve_field_alias_maps_type() {
        assert_eq!(super::resolve_field_alias("type").as_ref(), "bug_type");
    }

    #[test]
    fn resolve_field_alias_maps_group() {
        assert_eq!(super::resolve_field_alias("group").as_ref(), "bug_group");
    }

    #[test]
    fn resolve_field_alias_maps_file_loc() {
        assert_eq!(
            super::resolve_field_alias("file_loc").as_ref(),
            "bug_file_loc"
        );
    }

    #[test]
    fn resolve_field_alias_passes_through_unknown() {
        assert_eq!(super::resolve_field_alias("priority").as_ref(), "priority");
    }

    #[test]
    fn resolve_field_alias_passes_through_already_prefixed() {
        assert_eq!(
            super::resolve_field_alias("bug_status").as_ref(),
            "bug_status"
        );
    }

    #[test]
    fn resolve_field_alias_is_case_insensitive() {
        assert_eq!(super::resolve_field_alias("Status").as_ref(), "bug_status");
        assert_eq!(
            super::resolve_field_alias("SEVERITY").as_ref(),
            "bug_severity"
        );
    }

    #[tokio::test]
    async fn get_field_values_returns_values() {
        let mock = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/rest/field/bug/bug_status"))
            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!({
                "fields": [{
                    "values": [
                        {"name": "NEW", "sort_key": 100, "is_active": true, "can_change_to": [{"name": "ASSIGNED"}, {"name": "RESOLVED"}]},
                        {"name": "RESOLVED", "sort_key": 500, "is_active": true}
                    ]
                }]
            })))
            .mount(&mock)
            .await;

        let client = test_client(&mock.uri());
        let values = client.get_field_values("status").await.unwrap();
        assert_eq!(values.len(), 2);
        assert_eq!(values[0].name, "NEW");
        let transitions = values[0].can_change_to.as_ref().unwrap();
        assert_eq!(transitions.len(), 2);
        assert_eq!(transitions[0].name, "ASSIGNED");
    }

    #[tokio::test]
    async fn get_field_values_resolves_severity_alias() {
        let mock = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/rest/field/bug/bug_severity"))
            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!({
                "fields": [{
                    "values": [
                        {"name": "blocker", "sort_key": 100, "is_active": true},
                        {"name": "normal", "sort_key": 200, "is_active": true}
                    ]
                }]
            })))
            .mount(&mock)
            .await;

        let client = test_client(&mock.uri());
        let values = client.get_field_values("severity").await.unwrap();
        assert_eq!(values.len(), 2);
        assert_eq!(values[0].name, "blocker");
    }

    #[tokio::test]
    async fn get_field_values_unrecognized_field_returns_not_found() {
        let mock = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/rest/field/bug/nonexistent"))
            .respond_with(
                ResponseTemplate::new(200).set_body_json(serde_json::json!({"fields": []})),
            )
            .mount(&mock)
            .await;

        let client = test_client(&mock.uri());
        let err = client.get_field_values("nonexistent").await.unwrap_err();
        assert!(
            matches!(
                err,
                BzrError::NotFound {
                    resource: "field",
                    ..
                }
            ),
            "expected NotFound, got: {err}"
        );
    }
}