tix-tracker 0.12.0

//! The cycle/team/assignee scope indexes and the one issue snapshot every capacity
//! calculation reads (mission `cycle-capacity-planning-01M3C85C`, WP02).
//!
//! # One pass, one snapshot, one reading of every estimate
//!
//! [`IssueSnapshot::build`] walks the issues **once**. In that single walk it indexes
//! cycle membership, team membership, assignee membership, the shared #183 completion
//! answer, and each issue's estimate — parsed once and converted once per unit the
//! conversion table is resolved for. Every later question (`committed`, `completed`,
//! `remaining`, utilization, a per-scope detail view) is then a lookup, not a scan:
//! re-reading the store or re-parsing an estimate per scope is what NFR-001 exists to
//! forbid, and it is also how two surfaces start disagreeing about one repository.
//!
//! # Cycle membership resolves through the crate's one adapter
//!
//! An issue's `cycles` value is a **name**, and a name may be a hand-written
//! `[cycles.<name>]` cycle or one an issue-181 schedule generated. Both, and a
//! generated cycle's stable `<schedule-id>:<sequence>` id, resolve through
//! [`super::config::resolve_cycle`] — the crate's single cycle-reference resolver — so
//! a capacity scope naming any of the three selects exactly the same issues. The
//! snapshot keys membership on the **identity** that resolver answers with (a generated
//! cycle's id, a legacy cycle's name) and never on the spelling, so two spellings of
//! one cycle are one scope (data-model §2).
//!
//! # Team membership
//!
//! The only link the model offers between an issue and a team is the assignee: a team
//! is `[teams.<label>]` and its members are assignee identities. An issue therefore
//! belongs to a team when its `assignee`, canonicalised through
//! [`crate::assignee::parse_assignee`] (so `ada` and `@ada` are one identity, exactly
//! as [`super::config::validate`] folds them), is one of that team's canonical
//! members. An issue may belong to several teams; it contributes to each once.
//!
//! # References that resolve to nothing are diagnostics, not guesses
//!
//! An issue naming a cycle nothing resolves to is reported
//! ([`ScopeDiagnosticKind::UnknownScope`]) and contributes to **no** cycle scope: a
//! capacity entry can only be validated against a cycle that exists, so an unresolved
//! name could never be selected, and inventing a membership for it would be the silent
//! guess C-003 refuses. Two spellings of one identity inside one issue are reported too
//! ([`ScopeDiagnosticKind::AmbiguousScope`]) and deduplicated — the cycle counts once,
//! never twice.

use std::collections::btree_map::Entry;
use std::collections::{BTreeMap, BTreeSet};

use crate::assignee::parse_assignee;
use crate::config::Config;
use crate::cycle_schedule::identity::{CycleReference, ScheduleIndex};
use crate::error::render_diagnostics;
use crate::model::Issue;
use crate::wip::WipConfig;
use crate::workflow;

use super::config::{CapacityScopeKind, resolve_cycle};
use super::estimate::EstimateValue;

/// What a scope-index finding is about (data-model §5's vocabulary).
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum ScopeDiagnosticKind {
    /// An issue names a cycle that does not resolve to a record.
    UnknownScope,
    /// Two spellings in one issue resolve to one scope.
    AmbiguousScope,
}

impl ScopeDiagnosticKind {
    /// The stable spelling every surface prints.
    #[must_use]
    pub const fn as_str(self) -> &'static str {
        match self {
            Self::UnknownScope => "unknown_scope",
            Self::AmbiguousScope => "ambiguous_scope",
        }
    }
}

/// One scope-index finding: what it is, which scope, and which issue raised it.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ScopeDiagnostic {
    /// What is wrong.
    pub kind: ScopeDiagnosticKind,
    /// Which dimension the reference belongs to.
    pub scope_kind: CapacityScopeKind,
    /// The reference the issue wrote.
    pub reference: String,
    /// The issue that wrote it, when the finding came from an issue.
    pub issue: Option<u32>,
    /// One sentence saying what happened.
    pub message: String,
    /// A second sentence, when the first is not enough.
    pub because: Option<String>,
}

impl ScopeDiagnostic {
    /// A finding with its message.
    #[must_use]
    pub fn new(
        kind: ScopeDiagnosticKind,
        scope_kind: CapacityScopeKind,
        reference: impl Into<String>,
        message: impl Into<String>,
    ) -> Self {
        Self {
            kind,
            scope_kind,
            reference: reference.into(),
            issue: None,
            message: message.into(),
            because: None,
        }
    }

    /// Attach the issue the finding came from.
    #[must_use]
    pub fn for_issue(mut self, number: u32) -> Self {
        self.issue = Some(number);
        self
    }

    /// Add the sentence that says what to do about it.
    #[must_use]
    pub fn because(mut self, because: impl Into<String>) -> Self {
        self.because = Some(because.into());
        self
    }

    /// Render through the crate's one diagnostic renderer.
    #[must_use]
    pub fn render(&self) -> String {
        let mut pairs = vec![(self.kind.as_str(), self.message.as_str())];
        if let Some(because) = self.because.as_deref() {
            pairs.push((self.kind.as_str(), because));
        }
        render_diagnostics("E-tix-capacity", pairs)
    }
}

/// The one indexed issue snapshot capacity calculations read (T011).
///
/// Built by [`IssueSnapshot::build`] and immutable afterwards: every lookup is a map
/// read, so a calculation never touches a file, re-parses an estimate, or walks the
/// issue list again — there is no seam a lookup could parse through, and no interior
/// mutability to cache one in. The tally it exposes
/// ([`issue_visits`](Self::issue_visits),
/// [`estimates_parsed`](Self::estimates_parsed),
/// [`conversions_resolved`](Self::conversions_resolved)) is the pass's own record of the
/// parse and conversion work it performed, so a test can assert how much work the build
/// did instead of only that it was fast. What those counters do **not** observe is stated
/// on each of them.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct IssueSnapshot {
    /// Every issue number, in the order the pass saw them.
    numbers: Vec<u32>,
    /// A cycle identity -> its member issues, in issue order.
    by_cycle: BTreeMap<String, Vec<u32>>,
    /// A cycle identity -> the name it answers to, for a surface that lists scopes.
    cycle_names: BTreeMap<String, String>,
    /// A team label -> its member issues, in issue order.
    by_team: BTreeMap<String, Vec<u32>>,
    /// A canonical assignee identity -> its member issues, in issue order.
    by_assignee: BTreeMap<String, Vec<u32>>,
    /// An issue -> its estimate as stated, with the parse's diagnostics only.
    stated: BTreeMap<u32, EstimateValue>,
    /// An issue -> its estimate per target unit, conversion already applied.
    converted: BTreeMap<u32, BTreeMap<String, EstimateValue>>,
    /// The units every estimate was converted into, in a stable order.
    targets: Vec<String>,
    /// The issues #183's category service calls completed.
    completed: BTreeSet<u32>,
    /// The issues that belong to no cycle, team, or assignee scope.
    unscoped: Vec<u32>,
    /// The membership findings the pass produced, in the order it found them.
    diagnostics: Vec<ScopeDiagnostic>,
    /// How many issue records the pass's estimate seam walked.
    visits: usize,
    /// How many estimates that seam parsed.
    parses: usize,
    /// How many conversions that seam attempted: a readable estimate, per target unit.
    conversions: usize,
}

impl IssueSnapshot {
    /// Index `issues` in **one pass** against the repository's scopes and units.
    ///
    /// `index` is the caller's [`ScheduleIndex`], built from the cycle records
    /// (`crate::capacity::schedule_index`, or [`crate::cycle_schedule::registry::load_index`]
    /// — the same index either way). The units an estimate is converted into are the
    /// board's declared units plus every unit a configured capacity entry names, read
    /// from the config here: the conversion table is resolved **once**, at build time,
    /// so no calculation repeats it (R10).
    ///
    /// Conversions use the **default board**'s registry (`config.default_config()`,
    /// the board the CLI and other single-config surfaces run under, and the same board
    /// [`crate::workflow::resolution`] is built for here). A capacity scope names a
    /// cycle, a team, or an assignee and never a board, so there is no other board the
    /// arithmetic could run under; a unit *that* board does not declare is a
    /// `missing_conversion`/`unknown_unit` diagnostic per issue, never a guess.
    ///
    /// Completion is [`crate::workflow::is_completed`]'s answer (C-002): the snapshot
    /// records what the one status-category service decides and never re-derives it.
    #[must_use]
    #[allow(clippy::too_many_lines)]
    pub fn build(config: &Config, index: &ScheduleIndex, issues: &[Issue]) -> Self {
        let board = config.default_config();
        let resolution = workflow::resolution(config, board, "default");

        let mut targets: BTreeSet<String> = board.wip.units.keys().cloned().collect();
        for (_, entry) in config.capacity.iter() {
            if let Some(unit) = entry
                .unit
                .as_deref()
                .map(str::trim)
                .filter(|unit| !unit.is_empty())
            {
                targets.insert(unit.to_string());
            }
        }
        let targets: Vec<String> = targets.into_iter().collect();

        // Which teams a canonical assignee identity belongs to. Read from the config
        // once, so the issue pass stays a single pass.
        let mut teams_of: BTreeMap<String, Vec<String>> = BTreeMap::new();
        for (label, team) in &config.teams {
            for member in &team.members {
                let Some(handle) = parse_assignee(member) else {
                    continue;
                };
                let teams = teams_of.entry(handle).or_default();
                if !teams.contains(label) {
                    teams.push(label.clone());
                }
            }
        }

        let mut snapshot = Self {
            targets: targets.clone(),
            ..Self::default()
        };
        snapshot.numbers.reserve(issues.len());
        for issue in issues {
            snapshot.numbers.push(issue.number);

            let (stated, per_unit) = snapshot.read_issue(issue, &board.wip, &targets);
            snapshot.converted.insert(issue.number, per_unit);
            snapshot.stated.insert(issue.number, stated);

            if workflow::is_completed(issue, &resolution) {
                snapshot.completed.insert(issue.number);
            }

            // The cycle memberships, keyed on the identity `resolve_cycle` answers
            // with rather than on the spelling the issue used.
            let mut spellings: BTreeMap<String, String> = BTreeMap::new();
            let mut scoped = false;
            for reference in issue.cycles.iter().flatten() {
                let cycle = resolve_cycle(index, reference);
                let member = match &cycle {
                    CycleReference::Generated { name, id, .. } => {
                        Some((format!("cycle-id:{id}"), name.clone()))
                    }
                    CycleReference::Legacy { name } => {
                        Some((format!("cycle-name:{name}"), name.clone()))
                    }
                    CycleReference::Unknown { name } => {
                        snapshot.diagnostics.push(
                            ScopeDiagnostic::new(
                                ScopeDiagnosticKind::UnknownScope,
                                CapacityScopeKind::Cycle,
                                name.clone(),
                                format!(
                                    "issue #{} `cycles` names `{name}`, which does not resolve \
                                     to a cycle record",
                                    issue.number
                                ),
                            )
                            .for_issue(issue.number)
                            .because(
                                "the issue counts in no cycle until that cycle exists; an \
                                 unresolvable name is reported, never guessed (C-003)",
                            ),
                        );
                        None
                    }
                };
                let Some((key, name)) = member else {
                    continue;
                };
                snapshot.cycle_names.entry(key.clone()).or_insert(name);
                scoped = true;
                match spellings.entry(key.clone()) {
                    Entry::Vacant(slot) => {
                        slot.insert(reference.clone());
                        snapshot.by_cycle.entry(key).or_default().push(issue.number);
                    }
                    // A second spelling of one identity is one contribution, and the
                    // ambiguity is worth saying out loud.
                    Entry::Occupied(slot) => {
                        if slot.get() != reference {
                            snapshot.diagnostics.push(
                                ScopeDiagnostic::new(
                                    ScopeDiagnosticKind::AmbiguousScope,
                                    CapacityScopeKind::Cycle,
                                    reference.clone(),
                                    format!(
                                        "issue #{} `cycles` names `{reference}` and `{}`, \
                                         which resolve to one cycle",
                                        issue.number,
                                        slot.get()
                                    ),
                                )
                                .for_issue(issue.number)
                                .because("the cycle counts once, not twice"),
                            );
                        }
                    }
                }
            }

            if let Some(handle) = issue.assignee.as_deref().and_then(parse_assignee) {
                scoped = true;
                snapshot
                    .by_assignee
                    .entry(handle.clone())
                    .or_default()
                    .push(issue.number);
                for label in teams_of.get(&handle).into_iter().flatten() {
                    snapshot
                        .by_team
                        .entry(label.clone())
                        .or_default()
                        .push(issue.number);
                }
            }

            if !scoped {
                snapshot.unscoped.push(issue.number);
            }
        }

        for members in snapshot
            .by_cycle
            .values_mut()
            .chain(snapshot.by_team.values_mut())
            .chain(snapshot.by_assignee.values_mut())
        {
            members.sort_unstable();
            members.dedup();
        }
        snapshot.unscoped.sort_unstable();
        snapshot.unscoped.dedup();
        snapshot
    }

    /// One issue record's worth of the pass: the estimate as the issue stated it, and
    /// its reading in every target unit.
    ///
    /// This is the **one** place the snapshot parses an estimate or asks the registry
    /// for a conversion, and the one place the pass's tally
    /// ([`issue_visits`](Self::issue_visits),
    /// [`estimates_parsed`](Self::estimates_parsed),
    /// [`conversions_resolved`](Self::conversions_resolved)) grows. Keeping the work and
    /// its record in the same method is what lets those counters say something: work
    /// duplicated through this seam is counted twice and breaks the tests that anchor the
    /// tally to the slice. Work that bypasses the seam is not counted — see the
    /// accessors for exactly what the tally does and does not prove.
    fn read_issue(
        &mut self,
        issue: &Issue,
        registry: &WipConfig,
        targets: &[String],
    ) -> (EstimateValue, BTreeMap<String, EstimateValue>) {
        self.visits += 1;
        let stated = match issue.estimate.as_deref() {
            // A blank estimate states nothing, so it is unestimated rather than
            // invalid — the same rule the WIP aggregate follows.
            Some(raw) if !raw.trim().is_empty() => {
                self.parses += 1;
                EstimateValue::parse(issue.number, raw)
            }
            _ => EstimateValue::unestimated(),
        };
        let mut per_unit: BTreeMap<String, EstimateValue> = BTreeMap::new();
        for unit in targets {
            per_unit.insert(
                unit.clone(),
                stated.converted_to(issue.number, registry, unit),
            );
        }
        if stated.is_valid() {
            self.conversions += targets.len();
        }
        (stated, per_unit)
    }

    /// Every issue number, in the order the pass saw them.
    #[must_use]
    pub fn issues(&self) -> &[u32] {
        &self.numbers
    }

    /// How many issues the snapshot indexed.
    #[must_use]
    pub fn len(&self) -> usize {
        self.numbers.len()
    }

    /// Whether the snapshot indexed no issues.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.numbers.is_empty()
    }

    /// The units every estimate was converted into, in a stable order (T007).
    #[must_use]
    pub fn targets(&self) -> &[String] {
        &self.targets
    }

    /// An issue's estimate as stated: the raw text, the parsed unit and value, and the
    /// parse diagnostics. No conversion has been applied.
    #[must_use]
    pub fn estimate(&self, number: u32) -> Option<&EstimateValue> {
        self.stated.get(&number)
    }

    /// An issue's estimate converted into `unit`, conversion included.
    ///
    /// `None` only when the issue is not in the snapshot or `unit` was not in the
    /// conversion table — the units [`targets`](Self::targets) lists. Every issue in the
    /// snapshot otherwise answers, including an unestimated one (which stays
    /// unestimated) and an invalid one (whose diagnostics say why).
    #[must_use]
    pub fn estimate_in(&self, number: u32, unit: &str) -> Option<&EstimateValue> {
        self.converted.get(&number)?.get(unit)
    }

    /// Whether #183's category service calls this issue completed.
    #[must_use]
    pub fn is_completed(&self, number: u32) -> bool {
        self.completed.contains(&number)
    }

    /// The issues #183's category service calls completed, in issue order.
    #[must_use]
    pub fn completed(&self) -> &BTreeSet<u32> {
        &self.completed
    }

    /// The issues whose `cycles` resolve to `reference`'s identity.
    ///
    /// `reference` may be a hand-written cycle's name, a generated cycle's name, or a
    /// generated cycle's stable id: all three go through [`resolve_cycle`], so all
    /// three select the same set (T010). An unknown reference selects nobody.
    #[must_use]
    pub fn cycle_members(&self, index: &ScheduleIndex, reference: &str) -> &[u32] {
        let key = match resolve_cycle(index, reference) {
            CycleReference::Generated { id, .. } => format!("cycle-id:{id}"),
            CycleReference::Legacy { name } => format!("cycle-name:{name}"),
            CycleReference::Unknown { .. } => return &[],
        };
        self.by_cycle.get(&key).map_or(&[], Vec::as_slice)
    }

    /// The issues whose assignee is a member of team `label`.
    #[must_use]
    pub fn team_members(&self, label: &str) -> &[u32] {
        self.by_team.get(label).map_or(&[], Vec::as_slice)
    }

    /// The issues assigned to `reference`, by the model's assignee identity.
    ///
    /// The reference folds the way [`crate::assignee::parse_assignee`] folds it, so
    /// `ada` and `@ada` select the same issues and `Ada Lovelace <ada@example.com>` is
    /// its own identity — the same folding [`super::config::validate`] applies.
    #[must_use]
    pub fn assignee_members(&self, reference: &str) -> &[u32] {
        match parse_assignee(reference) {
            Some(handle) => self.by_assignee.get(&handle).map_or(&[], Vec::as_slice),
            None => &[],
        }
    }

    /// The issues in one scope, whichever dimension it is.
    ///
    /// The one call a calculation needs: it dispatches on the entry's scope kind, so
    /// no surface re-implements the per-kind lookup.
    #[must_use]
    pub fn members(
        &self,
        kind: CapacityScopeKind,
        reference: &str,
        index: &ScheduleIndex,
    ) -> &[u32] {
        match kind {
            CapacityScopeKind::Cycle => self.cycle_members(index, reference),
            CapacityScopeKind::Team => self.team_members(reference),
            CapacityScopeKind::Assignee => self.assignee_members(reference),
        }
    }

    /// The cycles with at least one member, by the name they answer to.
    #[must_use]
    pub fn cycle_scopes(&self) -> Vec<&str> {
        self.by_cycle
            .keys()
            .map(|key| {
                self.cycle_names
                    .get(key)
                    .map_or(key.as_str(), String::as_str)
            })
            .collect()
    }

    /// The teams with at least one member.
    #[must_use]
    pub fn team_scopes(&self) -> Vec<&str> {
        self.by_team.keys().map(String::as_str).collect()
    }

    /// The assignee identities with at least one member.
    #[must_use]
    pub fn assignee_scopes(&self) -> Vec<&str> {
        self.by_assignee.keys().map(String::as_str).collect()
    }

    /// The issues that belong to no cycle, team, or assignee scope, in issue order.
    ///
    /// An issue naming only a cycle that does not resolve is here too: it is in no
    /// scope a capacity entry could select.
    #[must_use]
    pub fn unscoped(&self) -> &[u32] {
        &self.unscoped
    }

    /// The membership findings the pass produced, in the order it found them.
    #[must_use]
    pub fn diagnostics(&self) -> &[ScopeDiagnostic] {
        &self.diagnostics
    }

    /// How many issue records the pass's estimate seam walked — the cursor's record.
    ///
    /// One per issue by construction: the pass walks the slice once and this counts the
    /// walk. It is a **discipline about this pass**, not evidence about code outside it —
    /// a second scan elsewhere in the crate would not appear here, and neither would a
    /// re-parse that bypassed the seam. The counters that can catch duplicated work are
    /// [`estimates_parsed`](Self::estimates_parsed) and
    /// [`conversions_resolved`](Self::conversions_resolved), which are incremented by the
    /// work itself.
    #[must_use]
    pub fn issue_visits(&self) -> usize {
        self.visits
    }

    /// How many estimates the pass parsed: one per issue that stated one.
    ///
    /// Counted where the parse happens, so a second read of the estimates through the
    /// same seam counts twice and is visible; the counters measure the work performed,
    /// not the absence of other code. A lookup adds nothing, because a lookup does not
    /// parse (NFR-001).
    #[must_use]
    pub fn estimates_parsed(&self) -> usize {
        self.parses
    }

    /// How many explicit conversions the pass attempted: one per issue with a readable
    /// estimate, per unit in [`targets`](Self::targets).
    ///
    /// This counts the **attempts** — the conversion seam was consulted exactly that
    /// many times, in this pass and nowhere else. Whether a particular attempt produced
    /// a number is read from the value itself
    /// ([`is_converted`](EstimateValue::is_converted)), because a refusal is a
    /// diagnostic on the value, not the loss of one.
    #[must_use]
    pub fn conversions_resolved(&self) -> usize {
        self.conversions
    }
}