import { Decision, effectiveStatus, sortDecisions } from './decisions';
import { DecisionAttachment, DiagramSummary, RegistryElement } from './format';
import { ModelIndex } from './service';

/** A decision as the lists show it. */
export interface DecisionRow {
  id: string;
  title?: string;
  /** Status shown: superseded when another decision supersedes it. */
  status: string;
  supersededBy?: string;
  date?: string;
  file: string;
}

/** A diagram an element is used in, as the pages show it. */
export interface UsedIn {
  path: string;
  title?: string;
  kind?: string;
}

/** A registry element as the model page and the registry page show it. */
export interface ElementCard {
  id: string;
  label?: string;
  sublabel?: string;
  type?: string;
  brand?: string;
  description?: string;
  /** Diagram that explains the element, relative to the model root. */
  diagram?: string;
  /** Registry file (relative to the model root) and 0-based line of the element. */
  file: string;
  line: number;
  usedIn: UsedIn[];
  /** Decisions about this element, from the decision files and from diagram attachments. */
  decisions: DecisionRow[];
}

/** What the model page shows; serialised into the webview. */
export interface ModelPanel {
  meta: { id?: string; name?: string; description?: string };
  /** True when main.archify also carries a diagram, shown between metadata and the list. */
  hasDiagram: boolean;
  groups: { group: string; diagrams: { path: string; title?: string; kind?: string; parseError?: string }[] }[];
  registry: ElementCard[];
  decisions: DecisionRow[];
  problems: string[];
  nested: string[];
}

/** What the decision page (one .archify-decision file) shows. */
export interface DecisionPanel {
  file: string;
  inModel: boolean;
  model?: { id?: string; name?: string };
  decision?: DecisionRow & { context?: string; decision?: string; consequences?: string; supersedes: DecisionRow[] };
  /** Decisions that supersede this one. */
  supersededBy: DecisionRow[];
  elements: ElementCard[];
  /** Diagrams the decision names. */
  diagrams: UsedIn[];
  /** Diagrams that point at the decision, with where. */
  referencedBy: { path: string; title?: string; kind?: string; attachedTo: DecisionAttachment }[];
  problems: string[];
}

/** What the registry page (one .archify-registry file) shows. */
export interface RegistryPanel {
  /** The registry file, relative to the model root (or its base name outside a model). */
  file: string;
  inModel: boolean;
  model?: { id?: string; name?: string };
  elements: ElementCard[];
  problems: string[];
}

function usedIn(id: string, usage: Map<string, string[]>, diagrams: DiagramSummary[]): UsedIn[] {
  return (usage.get(id) ?? []).map((path) => {
    const summary = diagrams.find((d) => d.relativePath === path);
    return { path, title: summary?.title, kind: summary?.kind };
  });
}

export function decisionRow(d: Decision, all: Map<string, Decision>): DecisionRow {
  const { status, supersededBy } = effectiveStatus(d, all);
  return { id: d.id, title: d.title, status, supersededBy, date: d.date, file: d.file };
}

/** Decisions about an element: named by the decision, or attached to its node in some diagram. */
function decisionsOfElement(id: string, index: Pick<ModelIndex, 'decisions' | 'decisionUsage'> | undefined): DecisionRow[] {
  if (!index) return [];
  const all = index.decisions.decisions;
  const ids = new Set<string>();
  for (const d of all.values()) if (d.elements.includes(id)) ids.add(d.id);
  for (const [decisionId, uses] of index.decisionUsage) if (uses.some((u) => u.attachedTo.kind === 'node' && u.attachedTo.id === id) && all.has(decisionId)) ids.add(decisionId);
  return sortDecisions([...ids].map((x) => all.get(x)!), all).map((d) => decisionRow(d, all));
}

export function elementCard(e: RegistryElement, usage: Map<string, string[]>, diagrams: DiagramSummary[], index?: Pick<ModelIndex, 'decisions' | 'decisionUsage'>): ElementCard {
  return {
    id: e.id,
    label: e.label,
    sublabel: e.sublabel,
    type: e.type,
    brand: e.brand,
    description: e.description,
    diagram: e.diagram,
    file: e.file,
    line: e.line,
    usedIn: usedIn(e.id, usage, diagrams),
    decisions: decisionsOfElement(e.id, index),
  };
}

const byId = (a: { id: string }, b: { id: string }) => a.id.localeCompare(b.id);

export function panelFromIndex(index: ModelIndex): ModelPanel {
  const registry = [...index.registry.elements.values()].sort(byId).map((e) => elementCard(e, index.usage, index.diagrams, index));
  const all = index.decisions.decisions;
  return {
    meta: index.meta,
    decisions: sortDecisions([...all.values()], all).map((d) => decisionRow(d, all)),
    hasDiagram: index.mainHasDiagram,
    groups: index.groups.map((g) => ({
      group: g.group,
      diagrams: g.diagrams.map((d) => ({ path: d.relativePath, title: d.title, kind: d.kind, parseError: d.parseError })),
    })),
    registry,
    problems: [...index.registry.problems, ...index.decisions.problems].map((p) => (p.file ? `${p.file}: ${p.message}` : p.message)),
    nested: index.nested,
  };
}

/** The registry page of one file inside a model: its elements, in file order, with usage. */
export function registryPanelFromIndex(index: ModelIndex, file: string): RegistryPanel {
  const elements = [...index.registry.elements.values()]
    .filter((e) => e.file === file)
    .sort((a, b) => a.line - b.line)
    .map((e) => elementCard(e, index.usage, index.diagrams, index));
  return {
    file,
    inModel: true,
    model: { id: index.meta.id, name: index.meta.name },
    elements,
    problems: index.registry.problems.filter((p) => p.file === file).map((p) => p.message),
  };
}

/** The registry page of a file outside a model: elements only, nothing is used anywhere. */
export function registryPanelStandalone(file: string, parsed: { elements: RegistryElement[]; problems: { message: string }[] }): RegistryPanel {
  return {
    file,
    inModel: false,
    elements: parsed.elements.map((e) => elementCard(e, new Map(), [])),
    problems: parsed.problems.map((p) => p.message),
  };
}

/** The decision page of one file inside a model. */
export function decisionPanelFromIndex(index: ModelIndex, file: string): DecisionPanel {
  const all = index.decisions.decisions;
  const d = [...all.values()].find((x) => x.file === file);
  const problems = index.decisions.problems.filter((p) => p.file === file).map((p) => p.message);
  const base = { file, inModel: true, model: { id: index.meta.id, name: index.meta.name }, problems };
  if (!d) return { ...base, supersededBy: [], elements: [], diagrams: [], referencedBy: [] };
  const rows = (ids: string[]) => ids.filter((id) => all.has(id)).map((id) => decisionRow(all.get(id)!, all));
  const elements = d.elements.filter((id) => index.registry.elements.has(id)).map((id) => elementCard(index.registry.elements.get(id)!, index.usage, index.diagrams, index));
  const summary = (path: string) => index.diagrams.find((x) => x.relativePath === path);
  return {
    ...base,
    decision: { ...decisionRow(d, all), context: d.context, decision: d.decision, consequences: d.consequences, supersedes: rows(d.supersedes) },
    supersededBy: [...all.values()].filter((x) => x.supersedes.includes(d.id)).map((x) => decisionRow(x, all)),
    elements,
    diagrams: d.diagrams.map((path) => ({ path, title: summary(path)?.title, kind: summary(path)?.kind })),
    referencedBy: (index.decisionUsage.get(d.id) ?? []).map((u) => ({ path: u.path, title: summary(u.path)?.title, kind: summary(u.path)?.kind, attachedTo: u.attachedTo })),
  };
}

/** The decision page of a file outside a model: the text only, and a note that it has lost its model. */
export function decisionPanelStandalone(file: string, parsed: { decision?: Decision; problems: { message: string }[] }): DecisionPanel {
  const d = parsed.decision;
  return {
    file,
    inModel: false,
    decision: d ? { id: d.id, title: d.title, status: d.status ?? 'proposed', date: d.date, file, context: d.context, decision: d.decision, consequences: d.consequences, supersedes: d.supersedes.map((id) => ({ id, status: 'unknown', file: '' })) } : undefined,
    supersededBy: [],
    elements: [],
    diagrams: d ? d.diagrams.map((path) => ({ path })) : [],
    referencedBy: [],
    problems: parsed.problems.map((p) => p.message),
  };
}