'use server'

import { revalidatePath } from 'next/cache'
import { cookies } from 'next/headers'
import { getIronSession } from 'iron-session'
import { z } from 'zod'
import { Prisma } from '@prisma/client'
import { prisma } from '@/lib/prisma'
import { SessionData, sessionOptions } from '@/lib/session'
import { parsePauseContext } from '@/lib/pause-context'
import { getJobConfigSnapshot } from '@/lib/job-config-snapshot'

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

export type PreFlightBlockerType =
  | 'task_no_plan'
  | 'open_question'
  | 'pbi_blocked'
  | 'task_cross_repo'

export interface PreFlightBlocker {
  type: PreFlightBlockerType
  id: string
  label: string
}

const StartSprintRunInput = z.object({ sprint_id: z.string().min(1) })
const ResumeSprintInput = z.object({ sprint_id: z.string().min(1) })
const CancelSprintRunInput = z.object({ sprint_run_id: z.string().min(1) })

interface StartResultOk {
  ok: true
  sprint_run_id: string
  jobs_count: number
}

interface StartResultBlocked {
  ok: false
  error: 'PRE_FLIGHT_BLOCKED'
  blockers: PreFlightBlocker[]
}

interface ErrorResult {
  ok: false
  error: string
  code: number
}

type StartResult = StartResultOk | StartResultBlocked | ErrorResult

// startSprintRunCore is gedeeld tussen startSprintRunAction en resumeSprintAction.
// Voert de pre-flight uit, maakt een SprintRun + ClaudeJobs (in PBI→Story→Task
// volgorde) binnen één transactie. Aanroeper levert sprint_id, user_id en de
// transactionele Prisma-client.
async function startSprintRunCore(
  tx: Prisma.TransactionClient,
  sprint_id: string,
  user_id: string,
): Promise<StartResultOk | StartResultBlocked | ErrorResult> {
  const sprint = await tx.sprint.findUnique({
    where: { id: sprint_id },
    include: { product: true },
  })
  if (!sprint) return { ok: false, error: 'SPRINT_NOT_FOUND', code: 404 }
  if (sprint.status !== 'OPEN')
    return { ok: false, error: 'SPRINT_NOT_ACTIVE', code: 400 }

  const activeRun = await tx.sprintRun.findFirst({
    where: {
      sprint_id,
      status: { in: ['QUEUED', 'RUNNING', 'PAUSED'] },
    },
  })
  if (activeRun)
    return { ok: false, error: 'SPRINT_RUN_ALREADY_ACTIVE', code: 409 }

  const stories = await tx.story.findMany({
    where: { sprint_id, status: { not: 'DONE' } },
    include: {
      pbi: true,
      tasks: {
        // EXCLUDED-taken worden hier impliciet uitgesloten: de filter is strikt
        // TO_DO, dus EXCLUDED/IN_PROGRESS/REVIEW/DONE/FAILED tasks komen niet
        // terecht in pre-flight blockers, jobs of SprintTaskExecution-rijen.
        where: { status: 'TO_DO' },
        orderBy: [{ sort_order: 'asc' }],
      },
    },
    orderBy: [{ sort_order: 'asc' }],
  })

  const blockers: PreFlightBlocker[] = []

  for (const s of stories) {
    for (const t of s.tasks) {
      if (!t.implementation_plan) {
        blockers.push({
          type: 'task_no_plan',
          id: t.id,
          label: `${t.code}: ${t.title}`,
        })
      }
    }
  }

  const openQuestions = await tx.claudeQuestion.findMany({
    where: { story: { sprint_id }, status: 'open' },
    select: { id: true, question: true },
  })
  for (const q of openQuestions) {
    blockers.push({
      type: 'open_question',
      id: q.id,
      label: q.question.slice(0, 80),
    })
  }

  const seenPbi = new Set<string>()
  for (const s of stories) {
    if (seenPbi.has(s.pbi.id)) continue
    seenPbi.add(s.pbi.id)
    if (s.pbi.status === 'BLOCKED' || s.pbi.status === 'FAILED') {
      blockers.push({
        type: 'pbi_blocked',
        id: s.pbi.id,
        label: `${s.pbi.code}: ${s.pbi.title}`,
      })
    }
  }

  // PBI-50: SPRINT_BATCH cross-repo blocker. Eén product-worktree =
  // alle tasks moeten in product.repo_url werken; task.repo_url-override
  // is incompatibel met deze flow.
  if (sprint.product.pr_strategy === 'SPRINT_BATCH') {
    for (const s of stories) {
      for (const t of s.tasks) {
        if (t.repo_url && t.repo_url !== sprint.product.repo_url) {
          blockers.push({
            type: 'task_cross_repo',
            id: t.id,
            label: `${t.code}: ${t.title}`,
          })
        }
      }
    }
  }

  if (blockers.length > 0) {
    return { ok: false, error: 'PRE_FLIGHT_BLOCKED', blockers }
  }

  const sprintRun = await tx.sprintRun.create({
    data: {
      sprint_id,
      started_by_id: user_id,
      status: 'QUEUED',
      pr_strategy: sprint.product.pr_strategy,
      started_at: new Date(),
    },
  })

  const orderedTasks = stories
    .slice()
    .sort(
      (a, b) =>
        a.pbi.priority - b.pbi.priority ||
        a.pbi.sort_order - b.pbi.sort_order ||
        a.sort_order - b.sort_order,
    )
    .flatMap((s) => s.tasks)

  // PBI-50: SPRINT_BATCH levert één SPRINT_IMPLEMENTATION-job die alle
  // tasks in één claude-sessie afhandelt. SprintTaskExecution-rows worden
  // server-side bij claim aangemaakt zodat order/base_sha consistent zijn
  // met de worktree-state op claim-tijd.
  if (sprint.product.pr_strategy === 'SPRINT_BATCH') {
    const sprintSnapshot = await getJobConfigSnapshot({
      kind: 'SPRINT_IMPLEMENTATION',
      productId: sprint.product_id,
    })
    await tx.claudeJob.create({
      data: {
        user_id,
        product_id: sprint.product_id,
        task_id: null,
        idea_id: null,
        sprint_run_id: sprintRun.id,
        kind: 'SPRINT_IMPLEMENTATION',
        status: 'QUEUED',
        ...sprintSnapshot,
      },
    })
    return { ok: true, sprint_run_id: sprintRun.id, jobs_count: 1 }
  }

  // STORY / SPRINT (per-task): bestaand pad. Snapshot per task zodat
  // task.requires_opus de cascade kan overrulen.
  for (const t of orderedTasks) {
    const taskSnapshot = await getJobConfigSnapshot({
      kind: 'TASK_IMPLEMENTATION',
      productId: sprint.product_id,
      taskId: t.id,
    })
    await tx.claudeJob.create({
      data: {
        user_id,
        product_id: sprint.product_id,
        task_id: t.id,
        sprint_run_id: sprintRun.id,
        kind: 'TASK_IMPLEMENTATION',
        status: 'QUEUED',
        ...taskSnapshot,
      },
    })
  }

  return { ok: true, sprint_run_id: sprintRun.id, jobs_count: orderedTasks.length }
}

export async function startSprintRunAction(input: unknown): Promise<StartResult> {
  const session = await getSession()
  if (!session.userId) return { ok: false, error: 'Niet ingelogd', code: 403 }
  if (session.isDemo)
    return { ok: false, error: 'Niet beschikbaar in demo-modus', code: 403 }

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

  const userId = session.userId
  const result = await prisma.$transaction((tx) =>
    startSprintRunCore(tx, parsed.data.sprint_id, userId),
  )

  if (result.ok) {
    revalidatePath(`/sprints/${parsed.data.sprint_id}`)
  }
  return result
}

export async function resumeSprintAction(input: unknown): Promise<StartResult> {
  const session = await getSession()
  if (!session.userId) return { ok: false, error: 'Niet ingelogd', code: 403 }
  if (session.isDemo)
    return { ok: false, error: 'Niet beschikbaar in demo-modus', code: 403 }

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

  const userId = session.userId
  const sprint_id = parsed.data.sprint_id

  const result = await prisma.$transaction(async (tx) => {
    const sprint = await tx.sprint.findUnique({ where: { id: sprint_id } })
    if (!sprint)
      return { ok: false as const, error: 'SPRINT_NOT_FOUND', code: 404 }
    if (sprint.status !== 'FAILED')
      return { ok: false as const, error: 'SPRINT_NOT_FAILED', code: 400 }

    // Sprint terug naar ACTIVE
    await tx.sprint.update({
      where: { id: sprint_id },
      data: { status: 'OPEN', completed_at: null },
    })

    // FAILED stories binnen sprint terug naar IN_SPRINT (DONE blijft)
    await tx.story.updateMany({
      where: { sprint_id, status: 'FAILED' },
      data: { status: 'IN_SPRINT' },
    })

    // PBIs van die stories: FAILED → READY (BLOCKED met rust laten)
    const storyPbiIds = (
      await tx.story.findMany({
        where: { sprint_id },
        select: { pbi_id: true },
        distinct: ['pbi_id'],
      })
    ).map((s) => s.pbi_id)
    await tx.pbi.updateMany({
      where: { id: { in: storyPbiIds }, status: 'FAILED' },
      data: { status: 'READY' },
    })

    // FAILED tasks → TO_DO (DONE blijft)
    await tx.task.updateMany({
      where: { story: { sprint_id }, status: 'FAILED' },
      data: { status: 'TO_DO' },
    })

    return startSprintRunCore(tx, sprint_id, userId)
  })

  if (result.ok) {
    revalidatePath(`/sprints/${sprint_id}`)
  }
  return result
}

const ResumePausedSprintRunInput = z.object({ sprint_run_id: z.string().min(1) })

interface ResumePausedResultOk {
  ok: true
}

type ResumePausedResult = ResumePausedResultOk | ErrorResult

export async function resumePausedSprintRunAction(
  input: unknown,
): Promise<ResumePausedResult> {
  const session = await getSession()
  if (!session.userId) return { ok: false, error: 'Niet ingelogd', code: 403 }
  if (session.isDemo)
    return { ok: false, error: 'Niet beschikbaar in demo-modus', code: 403 }

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

  const sprint_run_id = parsed.data.sprint_run_id

  const userId = session.userId
  const result = await prisma.$transaction(async (tx) => {
    const run = await tx.sprintRun.findUnique({
      where: { id: sprint_run_id },
      select: {
        id: true,
        status: true,
        sprint_id: true,
        pr_strategy: true,
        branch: true,
        pause_context: true,
      },
    })
    if (!run) return { ok: false as const, error: 'SPRINT_RUN_NOT_FOUND', code: 404 }
    if (run.status !== 'PAUSED')
      return { ok: false as const, error: 'SPRINT_RUN_NOT_PAUSED', code: 400 }

    const ctx = parsePauseContext(run.pause_context)
    if (ctx) {
      await tx.claudeQuestion.updateMany({
        where: { id: ctx.claude_question_id, status: 'open' },
        data: { status: 'closed' },
      })
    }

    // PBI-50: SPRINT_BATCH resume-pad — als de SprintRun hangt aan een
    // SPRINT_IMPLEMENTATION-job en er nog onafgemaakte SprintTaskExecution-rows
    // zijn (PENDING/RUNNING), maak NIEUWE SprintRun met previous_run_id +
    // hergebruikte branch + nieuwe SPRINT_IMPLEMENTATION-job. Oude SprintRun
    // gaat naar CANCELLED.
    const sprintJob = await tx.claudeJob.findFirst({
      where: { sprint_run_id, kind: 'SPRINT_IMPLEMENTATION' },
      select: { id: true, product_id: true },
    })
    if (sprintJob) {
      const remaining = await tx.sprintTaskExecution.count({
        where: {
          sprint_job_id: sprintJob.id,
          status: { in: ['PENDING', 'RUNNING'] },
        },
      })
      if (remaining > 0) {
        const newRun = await tx.sprintRun.create({
          data: {
            sprint_id: run.sprint_id,
            started_by_id: userId,
            status: 'QUEUED',
            pr_strategy: run.pr_strategy,
            branch: run.branch,
            previous_run_id: run.id,
            started_at: new Date(),
          },
        })
        const resumeSnapshot = await getJobConfigSnapshot({
          kind: 'SPRINT_IMPLEMENTATION',
          productId: sprintJob.product_id,
        })
        await tx.claudeJob.create({
          data: {
            user_id: userId,
            product_id: sprintJob.product_id,
            task_id: null,
            idea_id: null,
            sprint_run_id: newRun.id,
            kind: 'SPRINT_IMPLEMENTATION',
            status: 'QUEUED',
            ...resumeSnapshot,
          },
        })
        await tx.sprintRun.update({
          where: { id: sprint_run_id },
          data: {
            status: 'CANCELLED',
            pause_context: Prisma.JsonNull,
            finished_at: new Date(),
          },
        })
        return { ok: true as const, sprint_id: run.sprint_id, finalStatus: 'QUEUED' as const }
      }
    }

    const activeClaims = await tx.claudeJob.count({
      where: { sprint_run_id, status: { in: ['CLAIMED', 'RUNNING'] } },
    })
    const queuedJobs = await tx.claudeJob.count({
      where: { sprint_run_id, status: 'QUEUED' },
    })

    // PBI-49 P0: een STORY auto-merge MERGE_CONFLICT komt NA dat alle tasks
    // al DONE zijn. Terug naar QUEUED zou de SprintRun voor altijd laten
    // hangen — geen QUEUED job. Bij volledige scope-completion transitie
    // direct naar DONE; de dev heeft het conflict opgelost, de PR is van hen.
    let nextStatus: 'RUNNING' | 'QUEUED' | 'DONE'
    let finishedAt: Date | undefined
    if (activeClaims === 0 && queuedJobs === 0) {
      nextStatus = 'DONE'
      finishedAt = new Date()
    } else if (activeClaims > 0) {
      nextStatus = 'RUNNING'
    } else {
      nextStatus = 'QUEUED'
    }

    await tx.sprintRun.update({
      where: { id: sprint_run_id },
      data: {
        status: nextStatus,
        pause_context: Prisma.JsonNull,
        ...(finishedAt ? { finished_at: finishedAt } : {}),
      },
    })

    return { ok: true as const, sprint_id: run.sprint_id, finalStatus: nextStatus }
  })

  if (result.ok && 'sprint_id' in result) {
    revalidatePath(`/sprints/${result.sprint_id}`)
    return { ok: true }
  }
  return result
}

interface CancelResultOk {
  ok: true
}

type CancelResult = CancelResultOk | ErrorResult

export async function cancelSprintRunAction(input: unknown): Promise<CancelResult> {
  const session = await getSession()
  if (!session.userId) return { ok: false, error: 'Niet ingelogd', code: 403 }
  if (session.isDemo)
    return { ok: false, error: 'Niet beschikbaar in demo-modus', code: 403 }

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

  const sprint_run_id = parsed.data.sprint_run_id

  const result = await prisma.$transaction(async (tx) => {
    const run = await tx.sprintRun.findUnique({ where: { id: sprint_run_id } })
    if (!run)
      return { ok: false as const, error: 'SPRINT_RUN_NOT_FOUND', code: 404 }
    if (!['QUEUED', 'RUNNING', 'PAUSED'].includes(run.status))
      return { ok: false as const, error: 'SPRINT_RUN_NOT_CANCELLABLE', code: 400 }

    await tx.sprintRun.update({
      where: { id: sprint_run_id },
      data: { status: 'CANCELLED', finished_at: new Date() },
    })

    // Cancel openstaande task-jobs binnen deze run.
    // Tasks/Stories/PBIs/Sprint blijven hun status — cancel ≠ fail.
    await tx.claudeJob.updateMany({
      where: {
        sprint_run_id,
        status: { in: ['QUEUED', 'CLAIMED', 'RUNNING'] },
      },
      data: {
        status: 'CANCELLED',
        finished_at: new Date(),
      },
    })

    return { ok: true as const, sprint_id: run.sprint_id }
  })

  if (result.ok && 'sprint_id' in result) {
    revalidatePath(`/sprints/${result.sprint_id}`)
    return { ok: true }
  }
  return result
}