gitlab-tracker-core 0.4.1

use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Typed error returned by [`TrackerProvider`] operations.
///
/// Using `thiserror` instead of `Result<(), String>` gives callers a proper
/// type to match on, enables `?` propagation, and keeps error messages
/// consistent across all provider implementations.
#[derive(Debug, thiserror::Error)]
pub enum TrackerError {
    /// A network or HTTP-level failure occurred.
    #[error("Network error: {0}")]
    Network(String),
    /// The API token is missing, expired, or rejected.
    #[error("Authentication failed: {0}")]
    Auth(String),
    /// The requested ticket does not exist on the tracker.
    #[error("Ticket not found: {0}")]
    NotFound(String),
    /// The operation is not supported by this provider implementation.
    #[error("Not supported by this tracker: {0}")]
    Unsupported(String),
    /// Any other provider-specific error not covered by the variants above.
    #[error("{0}")]
    Other(String),
}

/// A lightweight reference to an external tracker ticket linked to a MR.
///
/// This struct is the only data type exchanged between the orchestrator
/// (`gitlab-tracker`) and any tracker plugin (Redmine, Jira, Trello, …).
/// It is intentionally flat and display-oriented — the orchestrator does not
/// need to know anything about the internal data model of the tracker.
/// Current schema version for [`LinkedTicket`].
///
/// Increment this constant whenever fields are added to or removed from `LinkedTicket`.
/// Any cached ticket whose `schema_version` is lower than this value will be invalidated
/// and re-fetched from the tracker on the next startup, ensuring stale caches never
/// silently hide newly added fields.
pub const LINKED_TICKET_SCHEMA_VERSION: u32 = 2;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LinkedTicket {
    /// Schema version — used to detect stale cached tickets after a struct upgrade.
    /// Defaults to `0` when absent (pre-versioning cache entries), which guarantees
    /// they are always invalidated on first run after this field was introduced.
    #[serde(default)]
    pub schema_version: u32,
    /// Numeric or alphanumeric identifier as shown in the tracker UI (e.g. "1234", "PROJ-42").
    pub id: String,
    /// Short title / subject of the ticket.
    pub subject: String,
    /// Human-readable status label (e.g. "In Progress", "Resolved").
    pub status: String,
    /// Direct URL to open the ticket in a browser.
    pub url: String,
    /// Original creator of the ticket (display name).
    /// `None` when not provided by the tracker.
    #[serde(default)]
    pub author: Option<String>,
    /// User currently assigned to the ticket (display name).
    /// `None` when unassigned or not supported by the tracker.
    #[serde(default)]
    pub assignee: Option<String>,
    /// Estimated time to complete the ticket, in seconds (e.g. from Redmine `/estimate`).
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub time_estimate: Option<u32>,
    /// Time already spent on the ticket, in seconds (e.g. from Redmine time entries).
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub time_spent: Option<u32>,
    /// Remaining time (ETC) in seconds as reported by the tracker.
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub time_remaining: Option<u32>,
    /// Type / category of the ticket as defined by the tracker (e.g. "Bug", "Evolution").
    /// The label is tracker-specific and may be in any language — do not hardcode colour logic
    /// on its value; use `label_colors` in `redmine.yaml` instead.
    /// `None` when not provided by the tracker.
    #[serde(default)]
    pub tracker_type: Option<String>,
    /// Priority label of the ticket as defined by the tracker (e.g. "High", "Low").
    /// Same caveat as `tracker_type` — colour mapping is user-configurable.
    /// `None` when not provided by the tracker.
    #[serde(default)]
    pub priority: Option<String>,
    /// Target version / sprint / release the ticket is assigned to (e.g. "v1.2.3", "Sprint 42").
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub version: Option<String>,
    /// Start date of the ticket in `YYYY-MM-DD` format.
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub start_date: Option<String>,
    /// Completion percentage as reported by the tracker (0–100).
    /// `None` when not set or not supported by the tracker.
    #[serde(default)]
    pub done_ratio: Option<u32>,
}

/// A time-tracking activity category as defined in the tracker (e.g. Redmine enumerations).
///
/// Activities are fetched once at startup and cached in `App` to populate
/// the Log Time popup selector without a network round-trip per keypress.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct Activity {
    /// Numeric identifier used when submitting a time entry via the API.
    pub id: u32,
    /// Human-readable label shown in the popup selector (e.g. "Development", "Design").
    pub name: String,
}

/// A single time entry recorded on a tracker ticket.
///
/// Returned by `fetch_time_entries` and displayed in the Inspector's TimeLog view.
#[derive(Debug, Clone)]
pub struct TimeEntry {
    /// Internal tracker identifier for this entry.
    pub id: u64,
    /// Duration in hours as stored by the tracker.
    pub hours: f32,
    /// Activity category associated with this entry.
    pub activity: Activity,
    /// Free-text comment left by the user when logging time.
    pub comment: String,
    /// Display name of the user who logged the time.
    pub user: String,
    /// Date on which the time was spent, in `YYYY-MM-DD` format.
    pub spent_on: String,
}

/// Payload sent to `log_time` when the user confirms the Log Time popup.
///
/// All fields are required — the popup enforces them before submission.
#[derive(Debug, Clone)]
pub struct TimeEntryRequest {
    /// Duration in hours (e.g. `1.5` for 1h30).
    pub hours: f32,
    /// Identifier of the selected activity category.
    pub activity_id: u32,
    /// Optional free-text comment. May be empty.
    pub comment: String,
    /// Date on which the time was spent, in `YYYY-MM-DD` format (defaults to today).
    pub spent_on: String,
}

/// Represents a single field change detected between two versions of a [`LinkedTicket`].
///
/// # Design
/// This enum is the **only** place in the codebase where "which fields are trackable"
/// is declared. Adding a new tracked field (e.g. `Sprint`, `DoneRatio`) only requires:
///   1. Adding a variant here.
///   2. Adding a match arm in `LinkedTicket::diff`.
///   3. Handling the new variant in the orchestrator's notification dispatch.
///
/// The orchestrator (`gitlab-tracker`) and notification plugin (`gitlab-tracker-notify`)
/// never need to know about field names directly — they only receive `TicketChange` values.
/// This satisfies OCP: providers (Redmine, Jira, …) and consumers (app, notify) are
/// decoupled from the field enumeration.
#[derive(Debug, Clone, PartialEq)]
pub enum TicketChange {
    /// The priority label changed (e.g. "Normal" → "High").
    Priority { old: String, new: String },
    /// The status label changed (e.g. "In Progress" → "Resolved").
    Status { old: String, new: String },
    /// The assignee changed (e.g. "Alice" → "Bob", or "Unassigned" when empty).
    Assignee { old: String, new: String },
    /// The target version/release changed (e.g. "v1.2" → "v1.3", or "None" when unset).
    Version { old: String, new: String },
    /// The completion percentage changed (0–100). Fires on both increase and decrease.
    /// `old` and `new` are formatted as "N%" strings for display consistency.
    DoneRatio { old: String, new: String },
}

impl TicketChange {
    /// Returns a human-readable label for the changed field, suitable for notification summaries.
    pub fn field_label(&self) -> &'static str {
        match self {
            TicketChange::Priority { .. } => "priority",
            TicketChange::Status { .. } => "status",
            TicketChange::Assignee { .. } => "assignee",
            TicketChange::Version { .. } => "version",
            TicketChange::DoneRatio { .. } => "progress",
        }
    }

    /// Returns the before/after values as `(&str, &str)` for display purposes.
    pub fn before_after(&self) -> (&str, &str) {
        match self {
            TicketChange::Priority { old, new }
            | TicketChange::Status { old, new }
            | TicketChange::Assignee { old, new }
            | TicketChange::Version { old, new }
            | TicketChange::DoneRatio { old, new } => (old.as_str(), new.as_str()),
        }
    }
}

impl LinkedTicket {
    /// Computes the list of tracked field changes between `self` (old) and `new`.
    ///
    /// Returns an empty `Vec` when nothing changed. The caller (orchestrator) should
    /// iterate over the result and dispatch notifications for each entry.
    ///
    /// # Design
    /// This is a **pure function** — no side effects, no I/O. Adding a new tracked field
    /// only requires adding a comparison block here and a variant to [`TicketChange`].
    /// The orchestrator and notification plugin remain unchanged for existing fields.
    pub fn diff(&self, new: &LinkedTicket) -> Vec<TicketChange> {
        let mut changes = Vec::new();

        // Helper: normalise an Option<&str> to a display string for comparison.
        let opt_str =
            |v: Option<&str>, fallback: &str| -> String { v.unwrap_or(fallback).to_string() };

        // Priority
        let old_priority = opt_str(self.priority.as_deref(), "None");
        let new_priority = opt_str(new.priority.as_deref(), "None");
        if old_priority != new_priority {
            changes.push(TicketChange::Priority {
                old: old_priority,
                new: new_priority,
            });
        }

        // Status
        if self.status != new.status {
            changes.push(TicketChange::Status {
                old: self.status.clone(),
                new: new.status.clone(),
            });
        }

        // Assignee
        let old_assignee = opt_str(self.assignee.as_deref(), "Unassigned");
        let new_assignee = opt_str(new.assignee.as_deref(), "Unassigned");
        if old_assignee != new_assignee {
            changes.push(TicketChange::Assignee {
                old: old_assignee,
                new: new_assignee,
            });
        }

        // Version / release
        let old_version = opt_str(self.version.as_deref(), "None");
        let new_version = opt_str(new.version.as_deref(), "None");
        if old_version != new_version {
            changes.push(TicketChange::Version {
                old: old_version,
                new: new_version,
            });
        }

        // Completion percentage — fires on both increase and decrease.
        // Formatted as "N%" so the notification body is immediately readable.
        let old_ratio = self.done_ratio.unwrap_or(0);
        let new_ratio = new.done_ratio.unwrap_or(0);
        if old_ratio != new_ratio {
            changes.push(TicketChange::DoneRatio {
                old: format!("{}%", old_ratio),
                new: format!("{}%", new_ratio),
            });
        }

        changes
    }
}

/// Raw colour maps for badge labels, expressed as plain `(bg, fg)` string pairs.
///
/// Strings use the same vocabulary as `AppConfig::parse_color` in `gitlab-tracker`:
/// named colours (`"red"`, `"cyan"`, `"dark_gray"`, …) or 6-digit hex (`"#ff6600"`).
///
/// This type lives in `core` so every provider can return it without depending on
/// `ratatui`. The orchestrator (`gitlab-tracker`) is responsible for converting the
/// strings to `ratatui::Color` values via its own `parse_color` function.
#[derive(Debug, Clone, Default)]
pub struct LabelColorMaps {
    /// Colour map for tracker-type labels (e.g. "Bug", "Evolution").
    /// Keys are matched case-insensitively by the renderer; `"*"` is a catch-all fallback.
    pub tracker_type: HashMap<String, (String, String)>,
    /// Colour map for priority labels (e.g. "Normal", "High").
    /// Keys are matched case-insensitively by the renderer; `"*"` is a catch-all fallback.
    pub priority: HashMap<String, (String, String)>,
}

/// Contract that every external tracker integration must implement.
///
/// # Design
/// - The orchestrator holds a `Box<dyn TrackerProvider + Send + Sync>` and
///   calls `detect_ticket_id` + `fetch_ticket` without knowing the concrete type.
/// - Each implementation lives in its own crate (e.g. `gitlab-tracker-redmine`).
/// - Adding a new tracker (Jira, Trello, Linear …) only requires a new crate
///   that implements this trait — no change to the orchestrator logic.
///
/// # Thread safety
/// `Send + Sync` is required because the provider is shared across async tasks.
#[async_trait]
pub trait TrackerProvider: Send + Sync {
    /// Human-readable name of the tracker (e.g. "Redmine", "Jira").
    /// Used for logging and UI labels.
    fn name(&self) -> &'static str;

    /// Attempts to extract a ticket identifier from the MR title and/or description.
    ///
    /// Returns the raw ticket id string (e.g. "1234") when found, `None` otherwise.
    /// Implementations should prefer the title over the description when both match.
    fn detect_ticket_id(&self, title: &str, description: &str) -> Option<String>;

    /// Fetches the full ticket details for the given raw ticket id.
    ///
    /// Returns `None` on network error, authentication failure, or when the
    /// ticket does not exist. The caller is responsible for caching results.
    async fn fetch_ticket(&self, ticket_id: &str) -> Option<LinkedTicket>;

    /// Builds the direct URL to the ticket from its id.
    ///
    /// This is a pure helper that may be called without a network round-trip
    /// (e.g. to open the browser immediately on keypress while the fetch is pending).
    fn ticket_url(&self, ticket_id: &str) -> String;

    /// Returns the badge colour maps for tracker-type and priority labels.
    ///
    /// The returned strings are colour names or hex codes understood by the
    /// orchestrator's `parse_color` function (`"red"`, `"#ff6600"`, …).
    ///
    /// Default implementation returns empty maps — the renderer then falls back
    /// to its hard-coded default (dark_gray background, white text).
    /// Override this in your provider to expose your config file's colour settings.
    fn label_colors(&self) -> LabelColorMaps {
        LabelColorMaps::default()
    }

    /// Fetches the list of time-tracking activity categories available in the tracker.
    ///
    /// Called once at startup (or on first popup open) and cached in `App`.
    /// Default implementation returns an empty list (opt-in capability).
    async fn fetch_activities(&self) -> Vec<Activity> {
        vec![]
    }

    /// Fetches all time entries recorded on the given ticket.
    ///
    /// Displayed in the Inspector's TimeLog view. Default returns empty (opt-in).
    async fn fetch_time_entries(&self, _ticket_id: &str) -> Vec<TimeEntry> {
        vec![]
    }

    /// Submits a new time entry on the given ticket.
    ///
    /// Returns `Ok(())` on success, or a [`TrackerError`] describing the failure.
    /// Default returns `TrackerError::Unsupported` — opt-in capability.
    async fn log_time(
        &self,
        _ticket_id: &str,
        _entry: TimeEntryRequest,
    ) -> Result<(), TrackerError> {
        Err(TrackerError::Unsupported(
            "Time logging not supported by this tracker".into(),
        ))
    }
}