import type { AppState, Feature, FeatureColumn, PulseEvent } from '../../store/types'
import { formatDateTime } from '../../utils/format'

const columnLabels: Record<FeatureColumn, string> = {
  now: 'Now',
  next: 'Next',
  later: 'Later',
  done: 'Done',
}

const groupFeatures = (features: Feature[]) => ({
  now: features.filter((feature) => feature.column === 'now'),
  next: features.filter((feature) => feature.column === 'next'),
  later: features.filter((feature) => feature.column === 'later'),
  done: features.filter((feature) => feature.column === 'done'),
})

const getFeatureLabel = (features: Feature[], featureId?: string) => {
  if (!featureId) return '—'
  return features.find((feature) => feature.id === featureId)?.title ?? `${featureId} (missing feature)`
}

const renderFeature = (feature: Feature) => {
  const criteria = feature.acceptance_criteria.length
    ? feature.acceptance_criteria.map((item) => `  - ${item}`).join('\n')
    : '  - None yet'

  return [
    `- **${feature.title}**`,
    `  - Description: ${feature.description || '—'}`,
    `  - Priority: ${feature.priority}`,
    `  - Status: ${feature.status}`,
    '  - Acceptance Criteria:',
    criteria,
    `  - Scope Notes: ${feature.scope_notes || '—'}`,
  ].join('\n')
}

const sortPulsesNewestFirst = (pulses: PulseEvent[]) =>
  [...pulses].sort((a, b) => b.timestamp.localeCompare(a.timestamp))

export const createAgentSessionPrompt = (
  state: AppState,
  options?: {
    featureId?: string
    target?: string
  },
) => {
  const grouped = groupFeatures(state.features)
  const target = options?.target || 'AI coding agent'
  const focusFeature = options?.featureId ? state.features.find((feature) => feature.id === options.featureId) ?? null : grouped.now[0] ?? null
  const relatedPulses = sortPulsesNewestFirst(state.pulses)
    .filter((pulse) => (focusFeature ? pulse.feature_id === focusFeature.id : true))
    .slice(0, 6)

  const renderFeatureBlock = (feature: Feature | null) => {
    if (!feature) return '- No specific feature selected yet. Choose the smallest useful next move.'

    return [
      `- Title: ${feature.title}`,
      `- Description: ${feature.description || '—'}`,
      `- Column: ${columnLabels[feature.column]}`,
      `- Priority: ${feature.priority}`,
      `- Status: ${feature.status}`,
      `- Acceptance criteria: ${feature.acceptance_criteria.length ? feature.acceptance_criteria.join('; ') : 'None yet'}`,
      `- Scope notes: ${feature.scope_notes || '—'}`,
    ].join('\n')
  }

  return [
    `You are the ${target} for ${state.project.name}.`,
    '',
    'Read the project context below and ship the smallest high-quality improvement that satisfies the focus feature without scope creep.',
    '',
    '## Project',
    `- Name: ${state.project.name}`,
    `- Pitch: ${state.project.one_line_pitch || '—'}`,
    `- Current goal: ${state.project.current_goal || '—'}`,
    `- Notes: ${state.project.notes || '—'}`,
    '',
    '## Focus Feature',
    renderFeatureBlock(focusFeature),
    '',
    '## Other Active Features',
    grouped.now.filter((feature) => feature.id !== focusFeature?.id).length
      ? grouped.now
          .filter((feature) => feature.id !== focusFeature?.id)
          .map((feature) => `- ${feature.title} (${feature.status}, ${feature.priority})`)
          .join('\n')
      : '- None beyond the focus feature.',
    '',
    '## Next Up',
    grouped.next.length ? grouped.next.map((feature) => `- ${feature.title} (${feature.status})`).join('\n') : '- Nothing queued yet.',
    '',
    '## Parking Lot / Do Not Implement Yet',
    state.parking_lot.length
      ? state.parking_lot.map((item) => `- ${item.title} — ${item.reason_parked || item.description || 'Parked for later.'}`).join('\n')
      : '- Nothing parked yet.',
    '',
    '## Recent Relevant Pulses',
    relatedPulses.length
      ? relatedPulses.map((pulse) => `- ${formatDateTime(pulse.timestamp)} · ${pulse.pulse_type} · ${pulse.message}`).join('\n')
      : '- No relevant pulse events yet.',
    '',
    '## Rules',
    '- Stay inside the focus feature unless a tiny supporting fix is required.',
    '- Do not implement Parking Lot items.',
    '- Preserve working behavior and avoid needless rewrites.',
    '- Prefer the smallest shippable step with clear evidence.',
    '',
    '## Deliver back',
    '- What changed',
    '- Files touched',
    '- How you verified it',
    '- Any blocker or follow-up you intentionally parked',
  ].join('\n')
}

export const createJsonExport = (state: AppState) =>
  JSON.stringify(
    {
      schema_version: state.schema_version,
      exported_at: new Date().toISOString(),
      project: state.project,
      features: state.features,
      parking_lot: state.parking_lot,
      pulses: state.pulses,
      settings: state.settings,
    },
    null,
    2,
  )

export const createPulseJsonl = (state: AppState) => state.pulses.map((pulse) => JSON.stringify(pulse)).join('\n')

export const createMarkdownPackage = (state: AppState) => {
  const grouped = groupFeatures(state.features)
  const recentPulses = sortPulsesNewestFirst(state.pulses).slice(0, 8)

  const projectSummary = `# Project Summary\n\n## Name\n${state.project.name}\n\n## One-Line Pitch\n${state.project.one_line_pitch || '—'}\n\n## Description\n${state.project.description || '—'}\n\n## Current Goal\n${state.project.current_goal || '—'}\n\n## Notes\n${state.project.notes || '—'}\n`

  const featurePlan = ['# Feature Plan']
  ;(['now', 'next', 'later', 'done'] as FeatureColumn[]).forEach((column) => {
    featurePlan.push(`\n## ${columnLabels[column]}`)
    const features = grouped[column]
    if (!features.length) {
      featurePlan.push('\n_No features in this column yet._')
      return
    }

    featurePlan.push('', ...features.map(renderFeature))
  })

  const parkingLot = [
    '# Parking Lot',
    '',
    ...(state.parking_lot.length
      ? state.parking_lot.map(
          (item) =>
            `- **${item.title}**\n  - Description: ${item.description || '—'}\n  - Reason parked: ${item.reason_parked || '—'}\n  - Possible future placement: ${item.possible_future_placement || '—'}\n  - Risk level: ${item.risk_level}`,
        )
      : ['_No parked ideas yet._']),
  ].join('\n')

  const pulseLog = [
    '# Pulse Log',
    '',
    ...(sortPulsesNewestFirst(state.pulses).length
      ? sortPulsesNewestFirst(state.pulses).map(
          (pulse) =>
            `- **${formatDateTime(pulse.timestamp)}** — ${pulse.pulse_type}\n  - Feature: ${getFeatureLabel(state.features, pulse.feature_id)}\n  - Source/Agent: ${pulse.source} / ${pulse.agent_id}\n  - Message: ${pulse.message}\n  - Confidence: ${pulse.confidence_score}\n  - Evidence: ${pulse.evidence_refs.length ? pulse.evidence_refs.join('; ') : '—'}`,
        )
      : ['_No pulse events yet._']),
  ].join('\n')

  const claudeContext = [
    '# AI Coding Context',
    '',
    '## Project',
    `${state.project.name} — ${state.project.one_line_pitch || '—'}`,
    '',
    '## Current Goal',
    state.project.current_goal || '—',
    '',
    '## Active Features',
    grouped.now.length ? grouped.now.map(renderFeature).join('\n\n') : '_None yet._',
    '',
    '## Next Features',
    grouped.next.length ? grouped.next.map(renderFeature).join('\n\n') : '_None yet._',
    '',
    '## Done Features',
    grouped.done.length ? grouped.done.map(renderFeature).join('\n\n') : '_None yet._',
    '',
    '## Parking Lot / Do Not Implement Yet',
    state.parking_lot.length
      ? state.parking_lot
          .map((item) => `- ${item.title} — ${item.reason_parked || item.description || 'Parked for later.'}`)
          .join('\n')
      : '_No parked ideas yet._',
    '',
    '## Recent Pulse Events',
    recentPulses.length
      ? recentPulses
          .map(
            (pulse) =>
              `- ${formatDateTime(pulse.timestamp)} — ${pulse.pulse_type} — ${pulse.message} (${getFeatureLabel(state.features, pulse.feature_id)})`,
          )
          .join('\n')
      : '_No recent pulse events yet._',
    '',
    '## Instructions for AI Developer',
    '- Only work on the selected feature.',
    '- Do not implement Parking Lot items.',
    '- Preserve working behavior.',
    '- Report changes and test steps.',
  ].join('\n')

  return {
    'PROJECT_SUMMARY.md': projectSummary,
    'FEATURE_PLAN.md': featurePlan.join('\n'),
    'PARKING_LOT.md': parkingLot,
    'PULSE_LOG.md': pulseLog,
    'CLAUDE_CONTEXT.md': claudeContext,
  }
}