'use server'

import { revalidatePath } from 'next/cache'
import { cookies } from 'next/headers'
import { getIronSession } from 'iron-session'
import { prisma } from '@/lib/prisma'
import { SessionData, sessionOptions } from '@/lib/session'
import { getAccessibleProduct, productAccessFilter } from '@/lib/product-access'
import {
  createSprintSchema,
  updateSprintDatesSchema,
  updateSprintGoalSchema,
} from '@/lib/schemas/sprint'
import { enforceUserRateLimit } from '@/lib/rate-limit'
import { propagateStatusUpwards } from '@/lib/tasks-status-update'
import { createWithCodeRetry, generateNextSprintCode } from '@/lib/code-server'
import { setActiveSprintCookie } from '@/lib/active-sprint'
import { z } from 'zod'

async function getSession() {
  return getIronSession<SessionData>(await cookies(), sessionOptions)
}

function hasDuplicateIds(ids: string[]) {
  return new Set(ids).size !== ids.length
}

type SprintFieldErrors = Record<string, string[]>

export async function createSprintAction(_prevState: unknown, formData: FormData) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd', code: 403 }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus', code: 403 }

  const limited = enforceUserRateLimit('create-sprint', session.userId)
  if (limited) return limited

  const parsed = createSprintSchema.safeParse({
    productId: formData.get('productId'),
    sprint_goal: formData.get('sprint_goal'),
    start_date: formData.get('start_date'),
    end_date: formData.get('end_date'),
    pbi_id: formData.get('pbi_id'),
  })
  if (!parsed.success) {
    return {
      error: 'Validatie mislukt',
      code: 422,
      fieldErrors: parsed.error.flatten().fieldErrors as SprintFieldErrors,
    }
  }

  const product = await getAccessibleProduct(parsed.data.productId, session.userId)
  if (!product) return { error: 'Product niet gevonden', code: 403 }

  const existing = await prisma.sprint.findFirst({
    where: { product_id: parsed.data.productId, status: 'OPEN' },
  })
  if (existing) return { error: 'Er is al een actieve Sprint voor dit product', sprintId: existing.id, code: 422 }

  const sprint = await createWithCodeRetry(
    () => generateNextSprintCode(parsed.data.productId),
    (code) =>
      prisma.sprint.create({
        data: {
          product_id: parsed.data.productId,
          code,
          sprint_goal: parsed.data.sprint_goal,
          status: 'OPEN',
          start_date: parsed.data.start_date,
          end_date: parsed.data.end_date,
        },
      }),
  )

  if (parsed.data.pbi_id) {
    const pbi = await prisma.pbi.findFirst({
      where: { id: parsed.data.pbi_id, product_id: parsed.data.productId },
      select: { id: true },
    })
    if (pbi) {
      const stories = await prisma.story.findMany({
        where: { pbi_id: pbi.id, sprint_id: null },
        orderBy: [{ priority: 'asc' }, { sort_order: 'asc' }],
        select: { id: true },
      })
      if (stories.length > 0) {
        const storyIds = stories.map(s => s.id)
        await prisma.$transaction([
          ...stories.map((s, i) =>
            prisma.story.update({
              where: { id: s.id },
              data: { sprint_id: sprint.id, status: 'IN_SPRINT', sort_order: i + 1 },
            }),
          ),
          prisma.task.updateMany({
            where: { story_id: { in: storyIds }, sprint_id: null },
            data: { sprint_id: sprint.id },
          }),
        ])
      }
    }
  }

  await setActiveSprintCookie(parsed.data.productId, sprint.id)
  revalidatePath(`/products/${parsed.data.productId}`, 'layout')
  return { success: true, sprintId: sprint.id }
}

export async function updateSprintDatesAction(_prevState: unknown, formData: FormData) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd', code: 403 }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus', code: 403 }

  const parsed = updateSprintDatesSchema.safeParse({
    id: formData.get('id'),
    start_date: formData.get('start_date'),
    end_date: formData.get('end_date'),
  })
  if (!parsed.success) {
    return {
      error: 'Validatie mislukt',
      code: 422,
      fieldErrors: parsed.error.flatten().fieldErrors as SprintFieldErrors,
    }
  }

  const sprint = await prisma.sprint.findFirst({
    where: { id: parsed.data.id, product: productAccessFilter(session.userId) },
  })
  if (!sprint) return { error: 'Sprint niet gevonden', code: 403 }

  await prisma.sprint.update({
    where: { id: parsed.data.id },
    data: { start_date: parsed.data.start_date, end_date: parsed.data.end_date },
  })
  revalidatePath(`/products/${sprint.product_id}/sprint`)
  return { success: true }
}

export async function updateSprintGoalAction(_prevState: unknown, formData: FormData) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd', code: 403 }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus', code: 403 }

  const parsed = updateSprintGoalSchema.safeParse({
    id: formData.get('id'),
    sprint_goal: formData.get('sprint_goal'),
  })
  if (!parsed.success) {
    return {
      error: 'Validatie mislukt',
      code: 422,
      fieldErrors: parsed.error.flatten().fieldErrors as SprintFieldErrors,
    }
  }

  const sprint = await prisma.sprint.findFirst({
    where: { id: parsed.data.id, product: productAccessFilter(session.userId) },
  })
  if (!sprint) return { error: 'Sprint niet gevonden', code: 403 }

  await prisma.sprint.update({ where: { id: parsed.data.id }, data: { sprint_goal: parsed.data.sprint_goal } })
  revalidatePath(`/products/${sprint.product_id}/sprint`)
  return { success: true }
}

export async function addStoryToSprintAction(sprintId: string, storyId: string) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd' }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }

  const sprint = await prisma.sprint.findFirst({
    where: { id: sprintId, product: productAccessFilter(session.userId) },
  })
  if (!sprint) return { error: 'Sprint niet gevonden' }

  const story = await prisma.story.findFirst({
    where: { id: storyId, product: productAccessFilter(session.userId) },
  })
  if (!story) return { error: 'Story niet gevonden' }
  if (story.product_id !== sprint.product_id) return { error: 'Story hoort niet bij deze Sprint' }

  const last = await prisma.story.findFirst({
    where: { sprint_id: sprintId },
    orderBy: { sort_order: 'desc' },
  })

  await prisma.story.update({
    where: { id: storyId },
    data: { sprint_id: sprintId, status: 'IN_SPRINT', sort_order: (last?.sort_order ?? 0) + 1.0 },
  })

  revalidatePath(`/products/${sprint.product_id}/sprint`)
  revalidatePath(`/products/${sprint.product_id}`)
  return { success: true }
}

export async function removeStoryFromSprintAction(storyId: string) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd' }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }

  const story = await prisma.story.findFirst({
    where: { id: storyId, product: productAccessFilter(session.userId) },
    include: { sprint: true },
  })
  if (!story) return { error: 'Story niet gevonden' }

  await prisma.story.update({
    where: { id: storyId },
    data: { sprint_id: null, status: 'OPEN' },
  })

  revalidatePath(`/products/${story.product_id}/sprint`)
  revalidatePath(`/products/${story.product_id}`)
  return { success: true }
}

export async function reorderSprintStoriesAction(sprintId: string, orderedIds: string[]) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd' }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
  if (hasDuplicateIds(orderedIds)) return { error: 'Ongeldige Sprint Backlog-volgorde' }

  const sprint = await prisma.sprint.findFirst({
    where: { id: sprintId, product: productAccessFilter(session.userId) },
  })
  if (!sprint) return { error: 'Sprint niet gevonden' }

  const stories = await prisma.story.findMany({
    where: { id: { in: orderedIds }, sprint_id: sprintId, product_id: sprint.product_id },
    select: { id: true },
  })
  if (stories.length !== orderedIds.length) return { error: 'Ongeldige Sprint Backlog-volgorde' }

  await prisma.$transaction(
    orderedIds.map((id, i) =>
      prisma.story.update({ where: { id }, data: { sort_order: i + 1.0 } })
    )
  )

  revalidatePath(`/products/${sprint.product_id}/sprint`)
  return { success: true }
}

export async function completeSprintAction(
  sprintId: string,
  decisions: Record<string, 'DONE' | 'OPEN'>
) {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd' }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }

  const sprint = await prisma.sprint.findFirst({
    where: { id: sprintId, product: productAccessFilter(session.userId) },
  })
  if (!sprint) return { error: 'Sprint niet gevonden' }

  const entries = Object.entries(decisions)
  if (entries.some(([, status]) => status !== 'DONE' && status !== 'OPEN')) {
    return { error: 'Ongeldige Sprint-afronding' }
  }

  const storyIds = entries.map(([storyId]) => storyId)
  if (hasDuplicateIds(storyIds)) return { error: 'Ongeldige Sprint-afronding' }

  const stories = await prisma.story.findMany({
    where: { id: { in: storyIds }, sprint_id: sprintId, product_id: sprint.product_id },
    select: { id: true, pbi_id: true },
  })
  if (stories.length !== storyIds.length) return { error: 'Ongeldige Sprint-afronding' }

  const affectedPbiIds = [...new Set(stories.map((s) => s.pbi_id))]
  const candidatePbis = await prisma.pbi.findMany({
    where: { id: { in: affectedPbiIds }, status: { not: 'DONE' } },
    select: { id: true, stories: { select: { id: true, status: true } } },
  })

  const decisionByStoryId = new Map(entries)
  const pbiIdsToMarkDone = candidatePbis
    .filter(
      (pbi) =>
        pbi.stories.length > 0 &&
        pbi.stories.every((s) => {
          const next = decisionByStoryId.get(s.id) ?? s.status
          return next === 'DONE'
        })
    )
    .map((p) => p.id)

  await prisma.$transaction([
    ...entries.map(([storyId, status]) =>
      prisma.story.update({
        where: { id: storyId },
        data: {
          status,
          sprint_id: status === 'OPEN' ? null : undefined,
        },
      })
    ),
    ...pbiIdsToMarkDone.map((id) =>
      prisma.pbi.update({ where: { id }, data: { status: 'DONE' } })
    ),
    prisma.sprint.update({
      where: { id: sprintId },
      data: { status: 'CLOSED', completed_at: new Date() },
    }),
  ])

  revalidatePath(`/products/${sprint.product_id}`)
  revalidatePath(`/products/${sprint.product_id}/sprint`)
  return { success: true }
}

export async function setAllSprintTasksDoneAction(
  sprintId: string,
): Promise<{ ok: true } | { ok: false; error: string }> {
  const session = await getSession()
  if (!session.userId) return { ok: false, error: 'Niet ingelogd' }
  if (session.isDemo) return { ok: false, error: 'Niet beschikbaar in demo-modus' }

  const sprint = await prisma.sprint.findFirst({
    where: { id: sprintId, product: productAccessFilter(session.userId) },
    select: { id: true, product_id: true },
  })
  if (!sprint) return { ok: false, error: 'Sprint niet gevonden' }

  const tasks = await prisma.task.findMany({
    where: { sprint_id: sprintId, product_id: sprint.product_id },
    select: { id: true },
  })

  await prisma.$transaction(async (tx) => {
    for (const task of tasks) {
      await propagateStatusUpwards(task.id, 'DONE', tx)
    }
  })

  revalidatePath(`/products/${sprint.product_id}/sprint`)
  return { ok: true }
}

const createSprintWithPbisSchema = z.object({
  productId: z.string().min(1),
  sprint_goal: z.string().min(1).max(2000),
  start_date: z.string().nullable().optional(),
  end_date: z.string().nullable().optional(),
  pbi_ids: z.array(z.string().min(1)).min(1),
})

function parseDate(value: string | null | undefined): Date | null {
  if (!value) return null
  const d = new Date(value)
  return Number.isNaN(d.getTime()) ? null : d
}

export async function createSprintWithPbisAction(input: {
  productId: string
  sprint_goal: string
  start_date?: string | null
  end_date?: string | null
  pbi_ids: string[]
}): Promise<{ success: true; sprintId: string } | { error: string; code: number }> {
  const session = await getSession()
  if (!session.userId) return { error: 'Niet ingelogd', code: 403 }
  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus', code: 403 }

  const limited = enforceUserRateLimit('create-sprint', session.userId)
  if (limited) return { error: limited.error, code: limited.code }

  const parsed = createSprintWithPbisSchema.safeParse(input)
  if (!parsed.success) return { error: 'Validatie mislukt', code: 422 }

  const product = await getAccessibleProduct(parsed.data.productId, session.userId)
  if (!product) return { error: 'Product niet gevonden', code: 403 }

  const pbis = await prisma.pbi.findMany({
    where: { id: { in: parsed.data.pbi_ids }, product_id: parsed.data.productId },
    select: { id: true },
  })
  if (pbis.length !== parsed.data.pbi_ids.length) {
    return { error: "Een of meer PBI's behoren niet tot dit product", code: 422 }
  }

  const sprint = await createWithCodeRetry(
    () => generateNextSprintCode(parsed.data.productId),
    (code) =>
      prisma.$transaction(async (tx) => {
        const created = await tx.sprint.create({
          data: {
            product_id: parsed.data.productId,
            code,
            sprint_goal: parsed.data.sprint_goal,
            status: 'OPEN',
            start_date: parseDate(parsed.data.start_date),
            end_date: parseDate(parsed.data.end_date),
          },
        })
        await tx.story.updateMany({
          where: { pbi_id: { in: parsed.data.pbi_ids } },
          data: { sprint_id: created.id, status: 'IN_SPRINT' },
        })
        await tx.task.updateMany({
          where: { story: { pbi_id: { in: parsed.data.pbi_ids } } },
          data: { sprint_id: created.id },
        })
        return created
      }),
  )

  await setActiveSprintCookie(parsed.data.productId, sprint.id)
  revalidatePath(`/products/${parsed.data.productId}`, 'layout')
  return { success: true, sprintId: sprint.id }
}