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

import {
  detectJunkReads,
  detectDuplicateReads,
  detectLowReadEditRatio,
  detectCacheBloat,
  detectBloatedClaudeMd,
  computeHealth,
  computeTrend,
  type ToolCall,
  type ApiCallMeta,
  type WasteFinding,
} from '../src/optimize.js'
import type { ProjectSummary } from '../src/types.js'

function call(name: string, input: Record<string, unknown>, sessionId = 's1', project = 'p1'): ToolCall {
  return { name, input, sessionId, project }
}

function emptyProjects(): ProjectSummary[] {
  return []
}

describe('detectJunkReads', () => {
  it('returns null below minimum threshold', () => {
    const calls = [
      call('Read', { file_path: '/x/node_modules/a.js' }),
      call('Read', { file_path: '/x/node_modules/b.js' }),
    ]
    expect(detectJunkReads(calls)).toBeNull()
  })

  it('flags when threshold is met', () => {
    const calls = [
      call('Read', { file_path: '/x/node_modules/a.js' }),
      call('Read', { file_path: '/x/node_modules/b.js' }),
      call('Read', { file_path: '/x/.git/config' }),
    ]
    const finding = detectJunkReads(calls)
    expect(finding).not.toBeNull()
    expect(finding!.impact).toBe('low')
  })

  it('scales impact with read count', () => {
    const make = (n: number) => Array.from({ length: n }, (_, i) =>
      call('Read', { file_path: `/x/node_modules/file-${i}.js` })
    )
    expect(detectJunkReads(make(25))!.impact).toBe('high')
    expect(detectJunkReads(make(10))!.impact).toBe('medium')
  })

  it('ignores non-junk paths', () => {
    const calls = [
      call('Read', { file_path: '/x/src/a.ts' }),
      call('Read', { file_path: '/x/src/b.ts' }),
      call('Read', { file_path: '/x/README.md' }),
    ]
    expect(detectJunkReads(calls)).toBeNull()
  })

  it('ignores non-read tools', () => {
    const calls = [
      call('Edit', { file_path: '/x/node_modules/a.js' }),
      call('Bash', { command: 'ls node_modules' }),
      call('Grep', { pattern: 'test', path: '/x/node_modules' }),
    ]
    expect(detectJunkReads(calls)).toBeNull()
  })

  it('handles missing file_path gracefully', () => {
    const calls = [
      call('Read', {}),
      call('Read', { file_path: null as unknown as string }),
    ]
    expect(detectJunkReads(calls)).toBeNull()
  })

  it('suggests CLAUDE.md advice listing detected and common junk dirs', () => {
    const calls = Array.from({ length: 5 }, () => call('Read', { file_path: '/x/node_modules/a.js' }))
    const finding = detectJunkReads(calls)!
    expect(finding.fix.type).toBe('paste')
    if (finding.fix.type === 'paste') {
      expect(finding.fix.text).toContain('node_modules')
    }
    expect(finding.fix.label).toContain('CLAUDE.md')
  })
})

describe('detectDuplicateReads', () => {
  it('counts same file read multiple times in same session', () => {
    const calls = [
      ...Array.from({ length: 4 }, () => call('Read', { file_path: '/src/a.ts' }, 's1')),
      ...Array.from({ length: 4 }, () => call('Read', { file_path: '/src/b.ts' }, 's1')),
    ]
    const finding = detectDuplicateReads(calls)
    expect(finding).not.toBeNull()
  })

  it('does not count across sessions', () => {
    const calls = [
      call('Read', { file_path: '/src/a.ts' }, 's1'),
      call('Read', { file_path: '/src/a.ts' }, 's2'),
      call('Read', { file_path: '/src/a.ts' }, 's3'),
    ]
    expect(detectDuplicateReads(calls)).toBeNull()
  })

  it('excludes junk directory reads', () => {
    const calls = Array.from({ length: 10 }, () =>
      call('Read', { file_path: '/x/node_modules/foo.js' }, 's1')
    )
    expect(detectDuplicateReads(calls)).toBeNull()
  })

  it('returns null for single reads', () => {
    const calls = [
      call('Read', { file_path: '/src/a.ts' }, 's1'),
      call('Read', { file_path: '/src/b.ts' }, 's1'),
    ]
    expect(detectDuplicateReads(calls)).toBeNull()
  })
})

describe('detectLowReadEditRatio', () => {
  it('returns null below minimum edit count', () => {
    const calls = [
      call('Edit', {}),
      call('Edit', {}),
      call('Read', {}),
    ]
    expect(detectLowReadEditRatio(calls)).toBeNull()
  })

  it('returns null when ratio is healthy', () => {
    const calls = [
      ...Array.from({ length: 40 }, () => call('Read', {})),
      ...Array.from({ length: 10 }, () => call('Edit', {})),
    ]
    expect(detectLowReadEditRatio(calls)).toBeNull()
  })

  it('flags when edits outpace reads', () => {
    const calls = [
      ...Array.from({ length: 5 }, () => call('Read', {})),
      ...Array.from({ length: 10 }, () => call('Edit', {})),
    ]
    const finding = detectLowReadEditRatio(calls)
    expect(finding).not.toBeNull()
    expect(finding!.impact).toBe('high')
  })

  it('counts Grep and Glob as reads for ratio', () => {
    const calls = [
      ...Array.from({ length: 40 }, () => call('Grep', {})),
      ...Array.from({ length: 10 }, () => call('Edit', {})),
    ]
    expect(detectLowReadEditRatio(calls)).toBeNull()
  })

  it('counts Write as edit', () => {
    const calls = [
      ...Array.from({ length: 15 }, () => call('Read', {})),
      ...Array.from({ length: 10 }, () => call('Write', {})),
    ]
    const finding = detectLowReadEditRatio(calls)
    expect(finding).not.toBeNull()
  })
})

describe('detectCacheBloat', () => {
  it('returns null below minimum api calls', () => {
    const apiCalls: ApiCallMeta[] = [
      { cacheCreationTokens: 80000, version: '2.1.100' },
      { cacheCreationTokens: 80000, version: '2.1.100' },
    ]
    expect(detectCacheBloat(apiCalls, emptyProjects())).toBeNull()
  })

  it('returns null when median is close to baseline', () => {
    const apiCalls: ApiCallMeta[] = Array.from({ length: 20 }, () => ({
      cacheCreationTokens: 50000,
      version: '2.1.98',
    }))
    expect(detectCacheBloat(apiCalls, emptyProjects())).toBeNull()
  })

  it('flags when median exceeds 1.4x baseline', () => {
    const apiCalls: ApiCallMeta[] = Array.from({ length: 20 }, () => ({
      cacheCreationTokens: 80000,
      version: '2.1.100',
    }))
    const finding = detectCacheBloat(apiCalls, emptyProjects())
    expect(finding).not.toBeNull()
  })
})

describe('detectBloatedClaudeMd', () => {
  it('returns null when no projects have CLAUDE.md', () => {
    const result = detectBloatedClaudeMd(new Set(['/nonexistent/path']))
    expect(result).toBeNull()
  })

  it('returns null for empty project set', () => {
    const result = detectBloatedClaudeMd(new Set())
    expect(result).toBeNull()
  })
})

describe('computeHealth', () => {
  it('returns A with 100 for no findings', () => {
    const { score, grade } = computeHealth([])
    expect(score).toBe(100)
    expect(grade).toBe('A')
  })

  function mockFinding(impact: 'high' | 'medium' | 'low'): WasteFinding {
    return {
      title: 't', explanation: 'e', impact, tokensSaved: 1000,
      fix: { type: 'paste', label: 'l', text: 't' },
    }
  }

  it('one low finding stays at A', () => {
    const { score, grade } = computeHealth([mockFinding('low')])
    expect(score).toBe(97)
    expect(grade).toBe('A')
  })

  it('two high findings drop to C', () => {
    const { score, grade } = computeHealth([mockFinding('high'), mockFinding('high')])
    expect(score).toBe(70)
    expect(grade).toBe('C')
  })

  it('caps penalty at 80 to prevent score below 20', () => {
    const findings = Array.from({ length: 20 }, () => mockFinding('high'))
    const { score } = computeHealth(findings)
    expect(score).toBe(20)
  })

  it('progresses grades predictably', () => {
    expect(computeHealth([mockFinding('low')]).grade).toBe('A')
    expect(computeHealth([mockFinding('medium')]).grade).toBe('A')
    expect(computeHealth([mockFinding('medium'), mockFinding('medium')]).grade).toBe('B')
    expect(computeHealth([mockFinding('high'), mockFinding('high'), mockFinding('high')]).grade).toBe('C')
    expect(computeHealth([mockFinding('high'), mockFinding('high'), mockFinding('high'), mockFinding('high'), mockFinding('high')]).grade).toBe('F')
  })
})

describe('computeTrend', () => {
  const window = 48 * 60 * 60 * 1000
  const baselineWindow = 5 * 24 * 60 * 60 * 1000

  it('returns active when no recent activity detected', () => {
    const trend = computeTrend({
      recentCount: 0, recentWindowMs: window,
      baselineCount: 100, baselineWindowMs: baselineWindow,
      hasRecentActivity: false,
    })
    expect(trend).toBe('active')
  })

  it('returns resolved when recent activity exists but zero waste in it', () => {
    const trend = computeTrend({
      recentCount: 0, recentWindowMs: window,
      baselineCount: 100, baselineWindowMs: baselineWindow,
      hasRecentActivity: true,
    })
    expect(trend).toBe('resolved')
  })

  it('returns improving when recent rate is less than half of baseline rate', () => {
    const trend = computeTrend({
      recentCount: 5, recentWindowMs: window,
      baselineCount: 100, baselineWindowMs: baselineWindow,
      hasRecentActivity: true,
    })
    expect(trend).toBe('improving')
  })

  it('returns active when recent rate matches baseline rate', () => {
    const recentRate = 100 / baselineWindow
    const recentCount = Math.ceil(recentRate * window)
    const trend = computeTrend({
      recentCount, recentWindowMs: window,
      baselineCount: 100, baselineWindowMs: baselineWindow,
      hasRecentActivity: true,
    })
    expect(trend).toBe('active')
  })

  it('returns active when baseline is empty (new finding)', () => {
    const trend = computeTrend({
      recentCount: 10, recentWindowMs: window,
      baselineCount: 0, baselineWindowMs: baselineWindow,
      hasRecentActivity: true,
    })
    expect(trend).toBe('active')
  })
})