'use server'

import { auth } from '@/auth'
import prisma from '@/lib/prisma'
import { getChatProvider } from '@/lib/ai/factory'
import { getSystemConfig } from '@/lib/config'
import { revalidatePath } from 'next/cache'

export interface OrganizationNote {
  id: string
  title: string
}

export interface OrganizationGroup {
  name: string
  isNew: boolean
  existingId?: string
  notes: OrganizationNote[]
}

export interface OrganizationPlan {
  notebookId: string
  groups: OrganizationGroup[]
}

export interface AnalyzeResult {
  success: boolean
  plan?: OrganizationPlan
  error?: string
}

export interface ExecuteResult {
  success: boolean
  created: number
  moved: number
  error?: string
}

/**
 * Analyze a notebook's notes with AI and suggest a sub-notebook organization plan.
 */
export async function analyzeNotebookForOrganization(notebookId: string): Promise<AnalyzeResult> {
  const session = await auth()
  if (!session?.user?.id) return { success: false, error: 'Non autorisé' }

  try {
    // 1. Fetch the target notebook (ensure ownership)
    const notebook = await prisma.notebook.findFirst({
      where: { id: notebookId, userId: session.user.id, trashedAt: null },
      select: { id: true, name: true },
    })
    if (!notebook) return { success: false, error: 'Carnet introuvable' }

    // 2. Fetch all notes in this notebook
    const notes = await prisma.note.findMany({
      where: {
        notebookId,
        userId: session.user.id,
        trashedAt: null,
        isArchived: false,
      },
      select: { id: true, title: true, content: true, labels: true },
      orderBy: { createdAt: 'asc' },
    })

    if (notes.length < 2) {
      return {
        success: false,
        error: 'Ce carnet contient moins de 2 notes — il n\'y a rien à organiser.',
      }
    }

    // 3. Fetch existing sub-notebooks
    const existingSubs = await prisma.notebook.findMany({
      where: { parentId: notebookId, userId: session.user.id, trashedAt: null },
      select: { id: true, name: true },
    })

    // 4. Build prompt context — truncate content to save tokens
    const notesContext = notes.map((n, i) => {
      const title = n.title || `Note sans titre ${i + 1}`
      const content = (n.content || '').slice(0, 300).replace(/\n+/g, ' ')
      let labelsStr = ''
      if (n.labels) {
        try {
          const parsed = JSON.parse(n.labels as string)
          if (Array.isArray(parsed)) labelsStr = parsed.join(', ')
        } catch {}
      }
      return `[${n.id}] "${title}"${labelsStr ? ` (tags: ${labelsStr})` : ''} — ${content}`
    }).join('\n')

    const existingSubsContext = existingSubs.length > 0
      ? `\nSous-carnets existants:\n${existingSubs.map(s => `- "${s.name}" (id: ${s.id})`).join('\n')}`
      : '\nIl n\'y a pas encore de sous-carnets.'

    const prompt = `Tu es un assistant d'organisation de notes. Analyse les notes suivantes du carnet "${notebook.name}" et regroupe-les par thème en proposant des sous-carnets.
${existingSubsContext}

Notes à organiser:
${notesContext}

RÈGLES IMPORTANTES:
- Regroupe les notes par thème ou sujet similaire.
- Propose entre 2 et 6 groupes maximum.
- Si un sous-carnet existant correspond déjà à un thème, utilise-le (indique son id).
- Les noms de groupe doivent être courts (2-4 mots), clairs et en français.
- N'inclus PAS toutes les notes si certaines sont trop générales ou ne correspondent à aucun groupe clair — laisse-les de côté.
- Réponds UNIQUEMENT avec du JSON valide, sans markdown, sans explication.

Format de réponse JSON attendu:
{
  "groups": [
    {
      "name": "Nom du sous-carnet",
      "existingId": "id-si-sous-carnet-existant-ou-null",
      "noteIds": ["id1", "id2", "id3"]
    }
  ]
}`

    // 5. Call AI using the chat provider (not embeddings provider)
    const config = await getSystemConfig()
    let provider
    try {
      provider = getChatProvider(config)
    } catch (providerErr) {
      console.error('[organize-notebook] Failed to get AI provider:', providerErr)
      return { success: false, error: `Fournisseur IA non configuré : ${(providerErr as Error).message}` }
    }

    let rawResponse: string
    try {
      rawResponse = await provider.generateText(prompt)
    } catch (aiErr) {
      console.error('[organize-notebook] AI generateText failed:', aiErr)
      return { success: false, error: `L'IA n'a pas pu répondre : ${(aiErr as Error).message}` }
    }

    // 6. Parse AI response
    let parsed: { groups: Array<{ name: string; existingId?: string | null; noteIds: string[] }> }
    try {
      // Clean possible markdown code blocks
      const cleaned = rawResponse.trim().replace(/^```json\n?/, '').replace(/\n?```$/, '')
      parsed = JSON.parse(cleaned)
    } catch {
      return { success: false, error: 'L\'IA n\'a pas pu générer un plan valide. Réessayez.' }
    }

    if (!parsed?.groups || !Array.isArray(parsed.groups)) {
      return { success: false, error: 'Réponse IA invalide.' }
    }

    // 7. Build the OrganizationPlan
    const noteMap = new Map(notes.map(n => [n.id, n]))
    const existingSubMap = new Map(existingSubs.map(s => [s.id, s]))

    const groups: OrganizationGroup[] = parsed.groups
      .filter(g => g.name && Array.isArray(g.noteIds) && g.noteIds.length > 0)
      .map(g => {
        const existingId = g.existingId && existingSubMap.has(g.existingId) ? g.existingId : undefined
        const groupNotes = g.noteIds
          .filter(id => noteMap.has(id))
          .map(id => {
            const n = noteMap.get(id)!
            return { id: n.id, title: n.title || 'Note sans titre' }
          })
        return {
          name: g.name,
          isNew: !existingId,
          existingId,
          notes: groupNotes,
        }
      })
      .filter(g => g.notes.length > 0)

    if (groups.length === 0) {
      return { success: false, error: 'L\'IA n\'a pas trouvé de groupes thématiques distincts.' }
    }

    return { success: true, plan: { notebookId, groups } }
  } catch (err) {
    console.error('[organize-notebook] Analysis error:', err)
    return { success: false, error: 'Une erreur s\'est produite lors de l\'analyse.' }
  }
}

/**
 * Execute an approved organization plan:
 * - Creates missing sub-notebooks (always as children of plan.notebookId)
 * - Moves notes to the correct sub-notebook
 */
export async function executeNotebookOrganization(plan: OrganizationPlan): Promise<ExecuteResult> {
  const session = await auth()
  if (!session?.user?.id) return { success: false, created: 0, moved: 0, error: 'Non autorisé' }

  try {
    // Verify notebook ownership
    const notebook = await prisma.notebook.findFirst({
      where: { id: plan.notebookId, userId: session.user.id, trashedAt: null },
      select: { id: true },
    })
    if (!notebook) return { success: false, created: 0, moved: 0, error: 'Carnet introuvable' }

    console.log('[organize-notebook] Executing plan:', JSON.stringify({
      notebookId: plan.notebookId,
      groups: plan.groups.map(g => ({ name: g.name, isNew: g.isNew, existingId: g.existingId, noteCount: g.notes.length }))
    }))

    let created = 0
    let moved = 0

    for (const group of plan.groups) {
      let targetNotebookId: string

      // Validate existingId: must be a real sub-notebook of plan.notebookId (not the parent itself)
      const validExistingId = group.existingId && group.existingId !== plan.notebookId
        ? group.existingId
        : undefined

      if (!group.isNew && validExistingId) {
        // Verify it's actually a child of plan.notebookId
        const verifiedSub = await prisma.notebook.findFirst({
          where: { id: validExistingId, parentId: plan.notebookId, userId: session.user.id, trashedAt: null },
          select: { id: true },
        })
        if (verifiedSub) {
          targetNotebookId = verifiedSub.id
        } else {
          // Fall through to create a new sub-notebook
          group.isNew = true
        }
      }

      if (group.isNew || !targetNotebookId!) {
        // Create new sub-notebook — always as a child of plan.notebookId
        const highestOrder = await prisma.notebook.findFirst({
          where: { parentId: plan.notebookId, userId: session.user.id },
          orderBy: { order: 'desc' },
          select: { order: true },
        })
        const nextOrder = (highestOrder?.order ?? -1) + 1

        const newSub = await prisma.notebook.create({
          data: {
            name: group.name.trim(),
            icon: '📁',
            color: '#A47148',
            order: nextOrder,
            parentId: plan.notebookId,   // always a sub-notebook
            userId: session.user.id,
          },
        })
        console.log(`[organize-notebook] Created sub-notebook "${newSub.name}" (id: ${newSub.id}) under ${plan.notebookId}`)
        targetNotebookId = newSub.id
        created++
      }

      // Move notes — update notebookId to the target sub-notebook
      const noteIds = group.notes.map(n => n.id)
      if (noteIds.length > 0) {
        const result = await prisma.note.updateMany({
          where: {
            id: { in: noteIds },
            userId: session.user.id,
          },
          data: { notebookId: targetNotebookId },
        })
        console.log(`[organize-notebook] Moved ${result.count} notes to "${group.name}"`)
        moved += result.count
      }
    }

    revalidatePath('/home')
    return { success: true, created, moved }
  } catch (err) {
    console.error('[organize-notebook] Execute error:', err)
    return { success: false, created: 0, moved: 0, error: 'Erreur lors de l\'exécution du plan.' }
  }
}