//! The types that cross into Kotlin.
//!
//! These MIRROR `thoughtsync_core::local::models` rather than reusing it. The core's
//! shapes are serde structs whose field names and optionality are contracted with the
//! shared Vue frontend; hanging uniffi derives on them would couple two very
//! different consumers to one definition and put a `serde_json::Value` (which has no
//! uniffi representation) in the middle of it.
//!
//! The cost of mirroring is drift — an Android client quietly missing a field the
//! desktop gained. Every conversion below therefore DESTRUCTURES the core struct
//! exhaustively instead of reading fields it cares about. Add a field to
//! `core::local::models::Note` and this file stops compiling until Android is told
//! what to do with it. That is the entire reason for the `let Core { .. } = value`
//! style here; please keep it.

use thoughtsync_core::local::models as core_models;
use thoughtsync_core::sync::client as core_client;
use thoughtsync_core::sync::compat as core_compat;
use thoughtsync_core::sync::engine as core_engine;
use thoughtsync_core::sync::pull as core_pull;
use thoughtsync_core::sync::push as core_push;
use thoughtsync_core::sync::state as core_state;

/// A note, with everything needed to render a card or open the editor.
///
/// Timestamps are RFC3339 strings, not a date type: that is what SQLite holds and
/// what the server speaks, and converting here would mean this layer picking a
/// calendar/timezone policy that belongs to the UI.
#[derive(Debug, Clone, uniffi::Record)]
pub struct Note {
    pub id: String,
    /// The note's NAME: its first non-blank body line, else its first checklist item.
    /// Always present. Derived by the core, never stored.
    pub display_title: String,
    pub body: String,
    pub position: i64,
    pub pinned: bool,
    pub archived: bool,
    pub trashed: bool,
    pub deleted_at: Option<String>,
    pub remind_at: Option<String>,
    pub recurrence: Option<String>,
    pub labels: Vec<NoteLabel>,
    pub items: Vec<ChecklistItem>,
    pub attachments: Vec<Attachment>,
    pub previews: Vec<LinkPreview>,
    pub created_at: Option<String>,
    pub updated_at: Option<String>,
}

/// A checklist item as it sits in a note's body.
///
/// Mirrors `derive::DerivedItem`. Carries the LINE because every renderer that walks
/// a body line by line needs the text, the state and the position together — the card
/// to draw a box in the right place, the block editor to know where one block ends.
#[derive(Debug, Clone, uniffi::Record)]
pub struct BodyItem {
    pub line: u32,
    pub text: String,
    pub checked: bool,
}

impl From<thoughtsync_core::local::derive::DerivedItem> for BodyItem {
    fn from(i: thoughtsync_core::local::derive::DerivedItem) -> Self {
        let thoughtsync_core::local::derive::DerivedItem {
            text,
            checked,
            line,
        } = i;
        BodyItem {
            line,
            text,
            checked,
        }
    }
}

/// One `#tag` and where it sits in a note's body.
///
/// Mirrors `derive::DerivedTag`. The card colours the tag where it was typed rather
/// than repeating it as a chip, so it needs the SPAN — and the offsets are UTF-16
/// code units precisely because Kotlin's `AnnotatedString` counts that way.
#[derive(Debug, Clone, uniffi::Record)]
pub struct BodyTag {
    pub line: u32,
    pub start: u32,
    pub end: u32,
    pub name: String,
}

impl From<thoughtsync_core::local::derive::DerivedTag> for BodyTag {
    fn from(t: thoughtsync_core::local::derive::DerivedTag) -> Self {
        let thoughtsync_core::local::derive::DerivedTag {
            line,
            start,
            end,
            name,
        } = t;
        BodyTag {
            line,
            start,
            end,
            name,
        }
    }
}

/// An Android build the linked server is offering, already judged to be newer.
///
/// A mirror rather than a re-export of `client::ClientRelease`, for the same
/// reason every other record here is one: the core's shapes are contracted with
/// other consumers, and `url` in particular is an implementation detail of how
/// the download is fetched — the app never needs it, because it asks the core to
/// do the downloading.
#[derive(Debug, Clone, uniffi::Record)]
pub struct ClientUpdate {
    /// For people to read.
    pub version: String,
    /// For machines to compare.
    pub version_code: i64,
    pub size: i64,
}

impl From<thoughtsync_core::sync::client::ClientRelease> for ClientUpdate {
    fn from(r: thoughtsync_core::sync::client::ClientRelease) -> Self {
        // Destructured exhaustively, like every other conversion in this file: a
        // field added upstream stops this compiling until Android is told what to
        // do with it, which turns silent drift into a build error.
        let thoughtsync_core::sync::client::ClientRelease {
            version,
            version_code,
            size,
            sha256: _,
            url: _,
        } = r;
        ClientUpdate {
            version,
            version_code,
            size,
        }
    }
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct NoteLabel {
    pub id: String,
    pub name: String,
    pub color: String,
    /// True when attached because of a `#tag` in the body, so the UI can show it is
    /// owned by the text and not independently removable.
    pub via_tag: bool,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct ChecklistItem {
    pub id: String,
    pub text: String,
    pub checked: bool,
    pub position: i64,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct Attachment {
    pub id: String,
    pub url: String,
    pub filename: Option<String>,
    pub mime: String,
    pub size: Option<i64>,
    pub sha256: Option<String>,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct LinkPreview {
    pub id: String,
    pub url: String,
    pub title: Option<String>,
    pub description: Option<String>,
    pub image_url: Option<String>,
    pub site_name: Option<String>,
}

impl From<core_models::Note> for Note {
    fn from(value: core_models::Note) -> Self {
        // Exhaustive on purpose — see the module header.
        let core_models::Note {
            id,
            display_title,
            body,
            position,
            pinned,
            archived,
            trashed,
            deleted_at,
            remind_at,
            recurrence,
            labels,
            items,
            attachments,
            previews,
            created_at,
            updated_at,
        } = value;
        Note {
            id,
            display_title,
            body,
            position,
            pinned,
            archived,
            trashed,
            deleted_at,
            remind_at,
            recurrence,
            labels: labels.into_iter().map(NoteLabel::from).collect(),
            items: items.into_iter().map(ChecklistItem::from).collect(),
            attachments: attachments.into_iter().map(Attachment::from).collect(),
            previews: previews.into_iter().map(LinkPreview::from).collect(),
            created_at,
            updated_at,
        }
    }
}

impl From<core_models::NoteLabel> for NoteLabel {
    fn from(value: core_models::NoteLabel) -> Self {
        let core_models::NoteLabel {
            id,
            name,
            color,
            via_tag,
        } = value;
        NoteLabel {
            id,
            name,
            color,
            via_tag,
        }
    }
}

impl From<core_models::ChecklistItem> for ChecklistItem {
    fn from(value: core_models::ChecklistItem) -> Self {
        let core_models::ChecklistItem {
            id,
            text,
            checked,
            position,
        } = value;
        ChecklistItem {
            id,
            text,
            checked,
            position,
        }
    }
}

impl From<core_models::Attachment> for Attachment {
    fn from(value: core_models::Attachment) -> Self {
        let core_models::Attachment {
            id,
            url,
            filename,
            mime,
            size,
            sha256,
        } = value;
        Attachment {
            id,
            url,
            filename,
            mime,
            size,
            sha256,
        }
    }
}

impl From<core_models::LinkPreview> for LinkPreview {
    fn from(value: core_models::LinkPreview) -> Self {
        let core_models::LinkPreview {
            id,
            url,
            title,
            description,
            image_url,
            site_name,
        } = value;
        LinkPreview {
            id,
            url,
            title,
            description,
            image_url,
            site_name,
        }
    }
}

/// A label, as the sidebar lists them.
#[derive(Debug, Clone, uniffi::Record)]
pub struct Label {
    pub id: String,
    pub name: String,
    /// Same colour vocabulary as notes, so one palette serves both.
    pub color: String,
    /// How many notes carry it. Only populated in listings — `None` elsewhere,
    /// matching the REST single-label responses.
    pub count: Option<i64>,
}

impl From<core_models::Label> for Label {
    fn from(value: core_models::Label) -> Self {
        let core_models::Label {
            id,
            name,
            color,
            count,
        } = value;
        Label {
            id,
            name,
            color,
            count,
        }
    }
}

// ─────────────────────────────  queries and edits  ─────────────────────────────

/// What the board is asking for. Mirrors the core's `ListQuery`.
#[derive(Debug, Clone, uniffi::Record)]
pub struct NoteQuery {
    /// "notes" | "archive" | "trash" | "reminders" | "labels" — the core validates.
    pub view: String,
    pub label_id: Option<String>,
    pub sort: Option<String>,
    pub facets: Option<NoteFacets>,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct NoteFacets {
    pub q: Option<String>,
    pub label: Option<Vec<String>>,
    pub has_reminder: Option<bool>,
    pub has_attachment: Option<bool>,
    pub created_after: Option<String>,
    pub created_before: Option<String>,
}

impl From<NoteQuery> for core_models::ListQuery {
    fn from(value: NoteQuery) -> Self {
        let NoteQuery {
            view,
            label_id,
            sort,
            facets,
        } = value;
        core_models::ListQuery {
            view,
            label_id,
            sort,
            facets: facets.map(core_models::Facets::from),
        }
    }
}

impl From<NoteFacets> for core_models::Facets {
    fn from(value: NoteFacets) -> Self {
        let NoteFacets {
            q,
            label,
            has_reminder,
            has_attachment,
            created_after,
            created_before,
        } = value;
        core_models::Facets {
            q,
            label,
            has_reminder,
            has_attachment,
            created_after,
            created_before,
        }
    }
}

/// A new note.
#[derive(Debug, Clone, uniffi::Record)]
pub struct NoteDraft {
    pub body: String,
    /// Checklist lines. A note can carry both a body and items (M13 step 2), so this
    /// is not an alternative to `body` — it is an addition to it.
    pub items: Option<Vec<String>>,
}

impl From<NoteDraft> for core_models::NoteCreateInput {
    fn from(value: NoteDraft) -> Self {
        let NoteDraft { body, items } = value;
        core_models::NoteCreateInput { body, items }
    }
}

/// One field-level change to a note.
///
/// A LIST of these rather than a struct of optional fields, because the core's patch
/// semantics distinguish three states — leave alone, set to a value, and clear to
/// null — and Kotlin has no way to express the third with a nullable field.
/// `remindAt: null` in a data class is indistinguishable from `remindAt` unset, so
/// the editor could never clear a reminder. Explicit `Clear*` variants say it out
/// loud, and Kotlin gets a sealed class it can `when` over exhaustively.
#[derive(Debug, Clone, uniffi::Enum)]
pub enum NoteEdit {
    Body { value: String },
    Pinned { value: bool },
    Archived { value: bool },
    RemindAt { value: String },
    ClearRemindAt,
    Recurrence { value: String },
    ClearRecurrence,
}

impl NoteEdit {
    /// The (key, value) pair this edit contributes to the core's JSON patch.
    ///
    /// The core reads a patch object where a present key means "change this" and a
    /// null value means "clear it" — the shape the REST API and the Tauri commands
    /// both already speak. Translating here keeps that one patch format in one
    /// place instead of teaching a second dialect to the store.
    fn entry(self) -> (&'static str, serde_json::Value) {
        use serde_json::Value;
        match self {
            NoteEdit::Body { value } => ("body", Value::String(value)),
            NoteEdit::Pinned { value } => ("pinned", Value::Bool(value)),
            NoteEdit::Archived { value } => ("archived", Value::Bool(value)),
            NoteEdit::RemindAt { value } => ("remind_at", Value::String(value)),
            NoteEdit::ClearRemindAt => ("remind_at", Value::Null),
            NoteEdit::Recurrence { value } => ("recurrence", Value::String(value)),
            NoteEdit::ClearRecurrence => ("recurrence", Value::Null),
        }
    }
}

/// Fold a list of edits into the single patch object the store applies.
///
/// Later edits win on a repeated key, which is what a caller batching "set a
/// reminder, then clear it" would expect.
pub fn patch_from(edits: Vec<NoteEdit>) -> serde_json::Value {
    let mut map = serde_json::Map::new();
    for edit in edits {
        let (key, value) = edit.entry();
        map.insert(key.to_string(), value);
    }
    serde_json::Value::Object(map)
}

// ─────────────────────────────────  sync  ─────────────────────────────────

/// What the UI may know about the link. Carries no device token, deliberately —
/// the core withholds it from `Status` for the same reason, and a bearer token has
/// no business in UI state.
#[derive(Debug, Clone, uniffi::Record)]
pub struct SyncStatus {
    pub linked: bool,
    pub server_url: Option<String>,
    pub last_cursor: i64,
    pub last_sync_at: Option<String>,
}

impl From<core_state::Status> for SyncStatus {
    fn from(value: core_state::Status) -> Self {
        let core_state::Status {
            linked,
            server_url,
            last_cursor,
            last_sync_at,
        } = value;
        SyncStatus {
            linked,
            server_url,
            last_cursor,
            last_sync_at,
        }
    }
}

/// What a server said about itself, before committing to anything.
#[derive(Debug, Clone, uniffi::Record)]
pub struct ProbeResult {
    /// Normalised by the core — this, not what the user typed, is what gets stored.
    pub base_url: String,
    pub site_name: Option<String>,
    pub version: Option<String>,
    pub trash_retention_days: Option<u32>,
    pub compatibility: Compatibility,
}

/// Whether this client and that server can sync at all.
#[derive(Debug, Clone, uniffi::Enum)]
pub enum Compatibility {
    Ok,
    /// Safe to sync, but these named capabilities are missing. The UI should say so
    /// rather than let a feature silently do nothing.
    Degraded {
        unavailable: Vec<String>,
    },
    /// Do not sync. `client_must_update` says which side can fix it, so the message
    /// can be actionable.
    Incompatible {
        reason: String,
        client_must_update: bool,
    },
}

impl From<core_compat::Compatibility> for Compatibility {
    fn from(value: core_compat::Compatibility) -> Self {
        match value {
            core_compat::Compatibility::Ok => Compatibility::Ok,
            core_compat::Compatibility::Degraded { unavailable } => {
                Compatibility::Degraded { unavailable }
            }
            core_compat::Compatibility::Incompatible {
                reason,
                client_must_update,
            } => Compatibility::Incompatible {
                reason,
                client_must_update,
            },
        }
    }
}

impl From<core_client::ProbeResult> for ProbeResult {
    fn from(value: core_client::ProbeResult) -> Self {
        let core_client::ProbeResult {
            base_url,
            server,
            compatibility,
        } = value;
        let core_compat::ServerInfo {
            site_name,
            version,
            // Protocol numbers are the raw material of the compatibility verdict,
            // which is already carried above in a form the UI can act on. Sending
            // them too would invite a second, worse judgement being made in Kotlin.
            sync_protocol_version: _,
            min_client_protocol_version: _,
            sync_features: _,
            trash_retention_days,
        } = server;
        ProbeResult {
            base_url,
            site_name,
            version,
            trash_retention_days,
            compatibility: compatibility.into(),
        }
    }
}

/// Who the server thinks this device belongs to.
#[derive(Debug, Clone, uniffi::Record)]
pub struct Identity {
    pub id: String,
    pub email: String,
    pub display_name: String,
}

impl From<core_client::Identity> for Identity {
    fn from(value: core_client::Identity) -> Self {
        let core_client::Identity {
            id,
            email,
            display_name,
        } = value;
        Identity {
            id,
            email,
            display_name,
        }
    }
}

/// What became of this device's token on the server during an unlink.
///
/// Separate from the local result because the local half always succeeds and the
/// remote half may not — someone unlinking a machine they are selling deserves to be
/// told plainly that the token is still live.
#[derive(Debug, Clone, uniffi::Enum)]
pub enum RevokeOutcome {
    Revoked,
    /// This server predates the self-revoke route. Only the web app can retire it.
    Unsupported,
    Failed {
        reason: String,
    },
    /// Nothing to revoke; the app wasn't linked.
    Skipped,
}

impl From<core_client::RevokeOutcome> for RevokeOutcome {
    fn from(value: core_client::RevokeOutcome) -> Self {
        match value {
            core_client::RevokeOutcome::Revoked => RevokeOutcome::Revoked,
            core_client::RevokeOutcome::Unsupported => RevokeOutcome::Unsupported,
            core_client::RevokeOutcome::Failed { reason } => RevokeOutcome::Failed { reason },
            core_client::RevokeOutcome::Skipped => RevokeOutcome::Skipped,
        }
    }
}

/// The result of one full push-then-pull cycle.
#[derive(Debug, Clone, uniffi::Record)]
pub struct SyncOutcome {
    pub push: PushSummary,
    pub pull: PullSummary,
    /// The state after the cycle, so the UI refreshes from one call rather than
    /// following every sync with a status query.
    pub status: SyncStatus,
}

/// Counts are `u64` because the core uses `usize`, which has no uniffi
/// representation. Widening is lossless on every target we build for; narrowing to
/// u32 would be a silent truncation waiting for a very large sync.
#[derive(Debug, Clone, uniffi::Record)]
pub struct PushSummary {
    pub batches: u64,
    pub sent: u64,
    pub created: u64,
    pub applied: u64,
    /// The server had a newer edit and kept it. Not a failure — the local row stops
    /// being dirty and the following pull adopts the server's version.
    pub kept: u64,
    pub noop: u64,
    /// Still dirty, and surfaced: these need a human (a duplicate label name is the
    /// realistic case). Silently retrying forever would be the wrong shape.
    pub rejected: u64,
    pub errors: Vec<String>,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct PullSummary {
    pub pages: u64,
    pub notes_applied: u64,
    pub notes_deleted: u64,
    pub labels_applied: u64,
    pub labels_deleted: u64,
    pub cursor: i64,
    /// Rows that still held unpushed local edits when the server's version landed on
    /// top. Should be 0 in a normal cycle, because push runs first; anything higher
    /// means local work was overwritten, which is worth saying out loud.
    pub clobbered_dirty: u64,
    pub blobs_downloaded: u64,
    /// Attachments whose bytes couldn't be fetched or failed verification. Counted
    /// rather than fatal.
    pub blobs_failed: u64,
}

impl From<core_push::PushSummary> for PushSummary {
    fn from(value: core_push::PushSummary) -> Self {
        let core_push::PushSummary {
            batches,
            sent,
            created,
            applied,
            kept,
            noop,
            rejected,
            errors,
        } = value;
        PushSummary {
            batches: batches as u64,
            sent: sent as u64,
            created: created as u64,
            applied: applied as u64,
            kept: kept as u64,
            noop: noop as u64,
            rejected: rejected as u64,
            errors,
        }
    }
}

impl From<core_pull::PullSummary> for PullSummary {
    fn from(value: core_pull::PullSummary) -> Self {
        let core_pull::PullSummary {
            pages,
            notes_applied,
            notes_deleted,
            labels_applied,
            labels_deleted,
            cursor,
            clobbered_dirty,
            blobs_downloaded,
            blobs_failed,
        } = value;
        PullSummary {
            pages: pages as u64,
            notes_applied: notes_applied as u64,
            notes_deleted: notes_deleted as u64,
            labels_applied: labels_applied as u64,
            labels_deleted: labels_deleted as u64,
            cursor,
            clobbered_dirty: clobbered_dirty as u64,
            blobs_downloaded: blobs_downloaded as u64,
            blobs_failed: blobs_failed as u64,
        }
    }
}

impl From<core_engine::SyncOutcome> for SyncOutcome {
    fn from(value: core_engine::SyncOutcome) -> Self {
        let core_engine::SyncOutcome { push, pull, status } = value;
        SyncOutcome {
            push: push.into(),
            pull: pull.into(),
            status: status.into(),
        }
    }
}

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

    #[test]
    fn a_set_and_a_clear_are_different_patch_entries() {
        let set = patch_from(vec![NoteEdit::RemindAt {
            value: "2026-01-01T00:00:00Z".to_string(),
        }]);
        assert_eq!(set["remind_at"], serde_json::json!("2026-01-01T00:00:00Z"));

        let cleared = patch_from(vec![NoteEdit::ClearRemindAt]);
        assert!(
            cleared["remind_at"].is_null(),
            "a clear must reach the store as JSON null — an absent key means \
             'leave alone', which is a different instruction"
        );
    }

    #[test]
    fn an_empty_edit_list_is_an_empty_patch() {
        // Not merely tidy: the core rejects a non-object patch, and a UI that
        // batches edits may well end up sending none.
        assert_eq!(patch_from(vec![]), serde_json::json!({}));
    }

    #[test]
    fn later_edits_win_on_a_repeated_field() {
        let patch = patch_from(vec![
            NoteEdit::RemindAt {
                value: "2026-01-01T00:00:00Z".to_string(),
            },
            NoteEdit::ClearRemindAt,
        ]);
        assert!(patch["remind_at"].is_null());
    }
}