import { describe, it, expect } from 'vitest'

import { formatCost } from '../src/format.js'
import type { ProjectSummary, SessionSummary } from '../src/types.js'

const EMPTY_CATEGORY_BREAKDOWN = {
  coding: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  debugging: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  feature: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  refactoring: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  testing: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  exploration: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  planning: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  delegation: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  git: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  'build/deploy': { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  conversation: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  brainstorming: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
  general: { turns: 0, costUSD: 0, retries: 0, editTurns: 0, oneShotTurns: 0 },
} satisfies SessionSummary['categoryBreakdown']

function makeSession(id: string, cost: number, timestamp = '2026-04-14T10:00:00Z'): SessionSummary {
  return {
    sessionId: id,
    project: 'test-project',
    firstTimestamp: timestamp,
    lastTimestamp: timestamp,
    totalCostUSD: cost,
    totalInputTokens: 0,
    totalOutputTokens: 0,
    totalCacheReadTokens: 0,
    totalCacheWriteTokens: 0,
    apiCalls: 1,
    turns: [],
    modelBreakdown: {},
    toolBreakdown: {},
    mcpBreakdown: {},
    bashBreakdown: {},
    categoryBreakdown: { ...EMPTY_CATEGORY_BREAKDOWN },
    skillBreakdown: {},
  }
}

function makeProject(name: string, sessions: SessionSummary[]): ProjectSummary {
  return {
    project: name,
    projectPath: name,
    sessions,
    totalCostUSD: sessions.reduce((s, x) => s + x.totalCostUSD, 0),
    totalApiCalls: sessions.reduce((s, x) => s + x.apiCalls, 0),
  }
}

// Logic replicated from TopSessions component
function getTopSessions(projects: ProjectSummary[], n = 5) {
  const all = projects.flatMap(p => p.sessions.map(s => ({ ...s, projectName: p.project })))
  return [...all].sort((a, b) => b.totalCostUSD - a.totalCostUSD).slice(0, n)
}

// Logic replicated from ProjectBreakdown component
function avgCostLabel(project: ProjectSummary): string {
  return project.sessions.length > 0
    ? formatCost(project.totalCostUSD / project.sessions.length)
    : '-'
}

describe('TopSessions - top-5 selection', () => {
  it('returns all sessions when fewer than 5 exist', () => {
    const project = makeProject('proj', [
      makeSession('s1', 1.0),
      makeSession('s2', 2.0),
    ])
    const top = getTopSessions([project])
    expect(top).toHaveLength(2)
    expect(top[0].totalCostUSD).toBe(2.0)
    expect(top[1].totalCostUSD).toBe(1.0)
  })

  it('returns exactly 5 when more than 5 sessions exist', () => {
    const sessions = [0.1, 0.5, 3.0, 1.0, 0.8, 2.0].map((cost, i) =>
      makeSession(`s${i}`, cost)
    )
    const project = makeProject('proj', sessions)
    const top = getTopSessions([project])
    expect(top).toHaveLength(5)
    expect(top[0].totalCostUSD).toBe(3.0)
    expect(top[4].totalCostUSD).toBe(0.5)
  })

  it('is stable on tied costs - preserves input order for equal values', () => {
    const sessions = [
      makeSession('s1', 1.0),
      makeSession('s2', 1.0),
      makeSession('s3', 1.0),
    ]
    const project = makeProject('proj', sessions)
    const top = getTopSessions([project])
    expect(top.map(s => s.sessionId)).toEqual(['s1', 's2', 's3'])
  })
})

describe('avg/s in ProjectBreakdown', () => {
  it('returns dash for a project with no sessions', () => {
    const project = makeProject('proj', [])
    expect(avgCostLabel(project)).toBe('-')
  })

  it('returns formatted average cost across sessions', () => {
    const sessions = [makeSession('s1', 2.0), makeSession('s2', 4.0)]
    const project = makeProject('proj', sessions)
    expect(avgCostLabel(project)).toBe(formatCost(3.0))
  })
})