import { Inject, Injectable, NotFoundException } from "@nestjs/common";
import { eq, and, desc, isNull } from "drizzle-orm";
import { schema, type Database } from "@courtmitra/db";
import {
  computeConsentHash,
  canonicalizeConsentPreview,
  canExecute,
  checkDefamation,
} from "@courtmitra/domain";
import { getCapabilities } from "@courtmitra/adapters";
import { STATE_RANK } from "@courtmitra/contracts";
import type {
  ConsentPreview,
  Action,
  RoutePlanStepDto,
  ActionPreviewDto,
  ActionPreviewResponse,
  ConsentGrantResponse,
  ExecuteActionResponse,
  ActionDetailDto,
  ActionAttemptDto,
  SubmissionDto,
  ActionExecutionRefused,
  CreateActionPreviewInput,
} from "@courtmitra/contracts";
import { DB } from "../db/db.module.js";
import { WorkflowService } from "../workflow/inngest.module.js";

function proofStateAfterForAction(actionType: string): ActionPreviewResponse["proofStateAfter"] {
  switch (actionType) {
    case "send_email":
    case "takedown":
      return "sent_by_email";
    case "generate_packet":
    case "prepare_portal":
      return "ready_for_user_submission";
    case "post_social":
      return "posted_to_social";
    default:
      return "draft_only";
  }
}

function actionAlreadyExecuted(action: Pick<Action, "status" | "proofState">): boolean {
  return action.status === "succeeded" || [
    "sent_by_email",
    "sent_via_channel",
    "posted_to_social",
    "user_confirmed_external_submission",
    "receipt_verified",
  ].includes(action.proofState ?? "");
}

@Injectable()
export class ActionsService {
  constructor(
    @Inject(DB) private readonly db: Database,
    @Inject(WorkflowService) private readonly workflow: WorkflowService,
  ) {}

  async previewAction(
    missionId: string,
    input: CreateActionPreviewInput,
    idempotencyKey?: string,
  ): Promise<ActionPreviewDto> {
    const [missionRow] = await this.db
      .select({ id: schema.missions.id, userId: schema.missions.userId })
      .from(schema.missions)
      .where(eq(schema.missions.id, missionId))
      .limit(1);
    if (!missionRow) throw new NotFoundException(`Mission not found: ${missionId}`);

    const [planRow] = await this.db
      .select()
      .from(schema.routePlans)
      .where(
        and(
          eq(schema.routePlans.id, input.routePlanId),
          eq(schema.routePlans.missionId, missionId),
          isNull(schema.routePlans.supersededAt),
        ),
      )
      .limit(1);
    if (!planRow) throw new NotFoundException(`Route plan not found for mission: ${missionId}`);

    const steps = planRow.steps as unknown as RoutePlanStepDto[];
    const step = steps.find((s) => s.stepNo === input.stepNo);
    if (!step) throw new NotFoundException(`Step ${input.stepNo} not found in route plan`);

    const defamationCheck = checkDefamation(input.body);
    const safeBody = defamationCheck.redactedBody;

    const preview: ConsentPreview = {
      actionType: step.actionType,
      destination: input.destination,
      public: false,
      body: safeBody,
      attachments: input.attachments,
      piiDisclosed: input.piiDisclosed,
      risks: input.risks,
    };

    const hash = computeConsentHash(preview);

    const canonicalized = canonicalizeConsentPreview(preview);
    const inputPayload: Record<string, unknown> = { ...canonicalized };
    if (input.subject) {
      inputPayload["subject"] = input.subject;
    }

    const [actionRow] = await this.db
      .insert(schema.actions)
      .values({
        missionId,
        routePlanId: input.routePlanId,
        actionType: step.actionType,
        title: step.title,
        description: step.description,
        inputPayload,
        canonicalPayloadHash: hash,
        consentRequired: true,
        status: "preview_ready",
        riskLevel: step.riskLevel,
        createdBy: "user",
        idempotencyKey: idempotencyKey ?? null,
      })
      .returning();

    // Only create snapshot if it does not regress state
    const [latestSnap] = await this.db
      .select({ state: schema.missionStatusSnapshots.state })
      .from(schema.missionStatusSnapshots)
      .where(eq(schema.missionStatusSnapshots.missionId, missionId))
      .orderBy(desc(schema.missionStatusSnapshots.createdAt))
      .limit(1);
    const currentRank = STATE_RANK[latestSnap?.state ?? ""] ?? -1;
    const newRank = STATE_RANK["actions_preview_ready"] ?? 0;
    if (newRank >= currentRank) {
      await this.db.insert(schema.missionStatusSnapshots).values({
        missionId,
        state: "actions_preview_ready",
        substate: null,
        headline: `Action preview ready: ${step.title}`,
        blockedReason: null,
        nextUserAction: "Review and approve the action to proceed.",
        nextSystemAction: "Wait for user consent before execution.",
        primaryButton: "Approve & send",
        danger: false,
        confidence: null,
      });
    }

    const previewResponse: ActionPreviewResponse = {
      actionId: actionRow!.id,
      actionType: step.actionType,
      destination: input.destination,
      public: false,
      bodyPreview: safeBody.slice(0, 500),
      attachments: input.attachments,
      piiDisclosed: input.piiDisclosed,
      risks: input.risks,
      actionPreviewHash: hash,
      proofStateAfter: proofStateAfterForAction(step.actionType),
    };

    const action: Action = {
      id: actionRow!.id,
      missionId: actionRow!.missionId,
      routePlanId: actionRow!.routePlanId,
      actionType: actionRow!.actionType as Action["actionType"],
      title: actionRow!.title,
      description: actionRow!.description,
      target: actionRow!.target as Record<string, unknown> | null,
      inputPayload: actionRow!.inputPayload as Record<string, unknown> | null,
      canonicalPayloadHash: actionRow!.canonicalPayloadHash,
      consentRequired: actionRow!.consentRequired,
      consentGrantId: actionRow!.consentGrantId,
      status: actionRow!.status as Action["status"],
      proofState: actionRow!.proofState as Action["proofState"],
      proofRef: actionRow!.proofRef as Record<string, unknown> | null,
      idempotencyKey: actionRow!.idempotencyKey,
      riskLevel: actionRow!.riskLevel as Action["riskLevel"],
      createdBy: actionRow!.createdBy as Action["createdBy"],
      createdAt: actionRow!.createdAt.toISOString(),
      updatedAt: actionRow!.updatedAt.toISOString(),
    };

    return {
      action,
      canonicalPayloadHash: hash,
      preview: previewResponse,
    };
  }

  async grantConsent(actionId: string): Promise<ConsentGrantResponse> {
    const [actionRow] = await this.db
      .select()
      .from(schema.actions)
      .where(eq(schema.actions.id, actionId))
      .limit(1);
    if (!actionRow) throw new NotFoundException(`Action not found: ${actionId}`);

    const [missionRow] = await this.db
      .select({ id: schema.missions.id, userId: schema.missions.userId })
      .from(schema.missions)
      .where(eq(schema.missions.id, actionRow.missionId))
      .limit(1);
    if (!missionRow) throw new NotFoundException(`Mission not found: ${actionRow.missionId}`);

    const [existingGrant] = await this.db
      .select()
      .from(schema.consentGrants)
      .where(
        and(
          eq(schema.consentGrants.missionId, actionRow.missionId),
          eq(schema.consentGrants.actionPreviewHash, actionRow.canonicalPayloadHash ?? ""),
          isNull(schema.consentGrants.revokedAt),
        ),
      )
      .orderBy(desc(schema.consentGrants.grantedAt))
      .limit(1);

    if (existingGrant) {
      // Link the existing consent to this action (it was created for a sibling action with the same hash).
      await this.db
        .update(schema.actions)
        .set({ consentGrantId: existingGrant.id, status: "approved", updatedAt: new Date() })
        .where(eq(schema.actions.id, actionId));

      return {
        id: existingGrant.id,
        actionId: actionRow.id,
        actionPreviewHash: existingGrant.actionPreviewHash,
        grantedAt: existingGrant.grantedAt?.toISOString() ?? new Date().toISOString(),
      };
    }

    const now = new Date();
    const [grant] = await this.db
      .insert(schema.consentGrants)
      .values({
        missionId: actionRow.missionId,
        userId: missionRow.userId,
        actionType: actionRow.actionType,
        actionPreviewHash: actionRow.canonicalPayloadHash ?? "",
        consentText: "I approve this action",
        channel: "web",
        grantedAt: now,
      })
      .returning();

    await this.db
      .update(schema.actions)
      .set({
        consentGrantId: grant!.id,
        status: "approved",
        updatedAt: new Date(),
      })
      .where(eq(schema.actions.id, actionId));

    return {
      id: grant!.id,
      actionId: actionRow.id,
      actionPreviewHash: grant!.actionPreviewHash,
      grantedAt: grant!.grantedAt?.toISOString() ?? now.toISOString(),
    };
  }

  async executeAction(
    actionId: string,
  ): Promise<ExecuteActionResponse | ActionExecutionRefused> {
    const [actionRow] = await this.db
      .select()
      .from(schema.actions)
      .where(eq(schema.actions.id, actionId))
      .limit(1);
    if (!actionRow) throw new NotFoundException(`Action not found: ${actionId}`);

    if (actionAlreadyExecuted({
      status: actionRow.status as Action["status"],
      proofState: actionRow.proofState as Action["proofState"],
    })) {
      return {
        refused: true,
        reason: "This action has already been executed.",
        code: "idempotency_key_used",
      };
    }

    let consentGrant: { actionPreviewHash: string } | null = null;
    if (actionRow.consentGrantId) {
      const [grantRow] = await this.db
        .select({ actionPreviewHash: schema.consentGrants.actionPreviewHash })
        .from(schema.consentGrants)
        .where(eq(schema.consentGrants.id, actionRow.consentGrantId))
        .limit(1);
      if (grantRow) {
        consentGrant = grantRow;
      }
    }

    const capabilities = getCapabilities();
    const action: Action = {
      id: actionRow.id,
      missionId: actionRow.missionId,
      routePlanId: actionRow.routePlanId,
      actionType: actionRow.actionType as Action["actionType"],
      title: actionRow.title,
      description: actionRow.description,
      target: null,
      inputPayload: actionRow.inputPayload as Record<string, unknown> | null,
      canonicalPayloadHash: actionRow.canonicalPayloadHash,
      consentRequired: actionRow.consentRequired,
      consentGrantId: actionRow.consentGrantId,
      status: actionRow.status as Action["status"],
      proofState: actionRow.proofState as Action["proofState"],
      proofRef: null,
      idempotencyKey: actionRow.idempotencyKey,
      riskLevel: actionRow.riskLevel as Action["riskLevel"],
      createdBy: actionRow.createdBy as Action["createdBy"],
      createdAt: actionRow.createdAt.toISOString(),
      updatedAt: actionRow.updatedAt.toISOString(),
    };

    const outgoingPreview: ConsentPreview = {
      actionType: actionRow.actionType,
      destination: (actionRow.inputPayload as Record<string, unknown>)?.["destination"] as string ?? "",
      public: false,
      body: (actionRow.inputPayload as Record<string, unknown>)?.["body"] as string ?? "",
      attachments: (actionRow.inputPayload as Record<string, unknown>)?.["attachments"] as ConsentPreview["attachments"] ?? [],
      piiDisclosed: (actionRow.inputPayload as Record<string, unknown>)?.["piiDisclosed"] as string[] ?? [],
      risks: (actionRow.inputPayload as Record<string, unknown>)?.["risks"] as string[] ?? [],
    };

    const gateResult = canExecute(action, consentGrant, outgoingPreview, capabilities);
    if (gateResult.refused) {
      return gateResult;
    }

    // Delegate execution to the Inngest worker. We DO NOT change status here —
    // the worker's executor sets it to "executing" inside its own transaction,
    // and canExecute allows "executing" so retries work.
    await this.workflow.send("action.execute_requested", {
      actionId: actionRow.id,
      missionId: actionRow.missionId,
    });

    return {
      actionId: actionRow.id,
      proofState: "draft_only",
      status: "approved",
      attempt: null,
    };
  }

  async getActionsForMission(missionId: string): Promise<ActionDetailDto[]> {
    const actionRows = await this.db
      .select()
      .from(schema.actions)
      .where(eq(schema.actions.missionId, missionId))
      .orderBy(desc(schema.actions.createdAt));

    return Promise.all(
      actionRows.map(async (actionRow) => {
        const [latestAttempt] = await this.db
          .select()
          .from(schema.actionAttempts)
          .where(eq(schema.actionAttempts.actionId, actionRow.id))
          .orderBy(desc(schema.actionAttempts.attemptNo))
          .limit(1);

        const submissionRows = await this.db
          .select()
          .from(schema.submissions)
          .where(eq(schema.submissions.actionId, actionRow.id))
          .orderBy(desc(schema.submissions.createdAt));

        const action: Action = {
          id: actionRow.id,
          missionId: actionRow.missionId,
          routePlanId: actionRow.routePlanId,
          actionType: actionRow.actionType as Action["actionType"],
          title: actionRow.title,
          description: actionRow.description,
          target: actionRow.target as Record<string, unknown> | null,
          inputPayload: actionRow.inputPayload as Record<string, unknown> | null,
          canonicalPayloadHash: actionRow.canonicalPayloadHash,
          consentRequired: actionRow.consentRequired,
          consentGrantId: actionRow.consentGrantId,
          status: actionRow.status as Action["status"],
          proofState: actionRow.proofState as Action["proofState"],
          proofRef: actionRow.proofRef as Record<string, unknown> | null,
          idempotencyKey: actionRow.idempotencyKey,
          riskLevel: actionRow.riskLevel as Action["riskLevel"],
          createdBy: actionRow.createdBy as Action["createdBy"],
          createdAt: actionRow.createdAt.toISOString(),
          updatedAt: actionRow.updatedAt.toISOString(),
        };

        const latestAttemptDto: ActionAttemptDto | null = latestAttempt
          ? {
              id: latestAttempt.id,
              adapterName: latestAttempt.adapterName,
              attemptNo: latestAttempt.attemptNo,
              status: latestAttempt.status,
              errorCode: latestAttempt.errorCode,
              errorMessage: latestAttempt.errorMessage,
              startedAt: latestAttempt.startedAt?.toISOString() ?? null,
              finishedAt: latestAttempt.finishedAt?.toISOString() ?? null,
            }
          : null;

        const submissionDtos: SubmissionDto[] = submissionRows.map((s) => ({
          id: s.id,
          proofState: s.proofState as SubmissionDto["proofState"],
          externalReference: s.externalReference,
          sentAt: s.sentAt?.toISOString() ?? null,
        }));

        return {
          action,
          latestAttempt: latestAttemptDto,
          submissions: submissionDtos,
        };
      }),
    );
  }

  async getAction(actionId: string): Promise<ActionDetailDto> {
    const [actionRow] = await this.db
      .select()
      .from(schema.actions)
      .where(eq(schema.actions.id, actionId))
      .limit(1);
    if (!actionRow) throw new NotFoundException(`Action not found: ${actionId}`);

    const [latestAttempt] = await this.db
      .select()
      .from(schema.actionAttempts)
      .where(eq(schema.actionAttempts.actionId, actionId))
      .orderBy(desc(schema.actionAttempts.attemptNo))
      .limit(1);

    const submissionRows = await this.db
      .select()
      .from(schema.submissions)
      .where(eq(schema.submissions.actionId, actionId))
      .orderBy(desc(schema.submissions.createdAt));

    const action: Action = {
      id: actionRow.id,
      missionId: actionRow.missionId,
      routePlanId: actionRow.routePlanId,
      actionType: actionRow.actionType as Action["actionType"],
      title: actionRow.title,
      description: actionRow.description,
      target: actionRow.target as Record<string, unknown> | null,
      inputPayload: actionRow.inputPayload as Record<string, unknown> | null,
      canonicalPayloadHash: actionRow.canonicalPayloadHash,
      consentRequired: actionRow.consentRequired,
      consentGrantId: actionRow.consentGrantId,
      status: actionRow.status as Action["status"],
      proofState: actionRow.proofState as Action["proofState"],
      proofRef: actionRow.proofRef as Record<string, unknown> | null,
      idempotencyKey: actionRow.idempotencyKey,
      riskLevel: actionRow.riskLevel as Action["riskLevel"],
      createdBy: actionRow.createdBy as Action["createdBy"],
      createdAt: actionRow.createdAt.toISOString(),
      updatedAt: actionRow.updatedAt.toISOString(),
    };

    const latestAttemptDto: ActionAttemptDto | null = latestAttempt
      ? {
          id: latestAttempt.id,
          adapterName: latestAttempt.adapterName,
          attemptNo: latestAttempt.attemptNo,
          status: latestAttempt.status,
          errorCode: latestAttempt.errorCode,
          errorMessage: latestAttempt.errorMessage,
          startedAt: latestAttempt.startedAt?.toISOString() ?? null,
          finishedAt: latestAttempt.finishedAt?.toISOString() ?? null,
        }
      : null;

    const submissions: SubmissionDto[] = submissionRows.map((s) => ({
      id: s.id,
      proofState: s.proofState as SubmissionDto["proofState"],
      externalReference: s.externalReference,
      sentAt: s.sentAt?.toISOString() ?? null,
    }));

    return {
      action,
      latestAttempt: latestAttemptDto,
      submissions,
    };
  }

  async confirmExternalSubmission(actionId: string, platform: string, externalUrl?: string) {
    const [actionRow] = await this.db
      .select()
      .from(schema.actions)
      .where(eq(schema.actions.id, actionId))
      .limit(1);
    if (!actionRow) throw new NotFoundException(`Action not found: ${actionId}`);

    // Determine the correct headline based on action type
    const actionType = actionRow.actionType;
    const isSocialPost = platform === "x" || platform === "threads" || platform === "instagram";
    let headline: string;
    let nextUserAction: string;
    let primaryButton: string | null;

    if (isSocialPost) {
      headline = `Social post published on ${platform} — waiting for public response.`;
      nextUserAction = "Monitor replies on your post and report any response here.";
      primaryButton = "View post";
    } else if (actionType === "send_email") {
      headline = "Email sent to authority — waiting for response.";
      nextUserAction = "Check for replies from the authority and report back.";
      primaryButton = null;
    } else {
      headline = `Action "${actionRow.title}" confirmed — waiting for response.`;
      nextUserAction = "Wait for the authority to respond. You can also escalate on social media below.";
      primaryButton = null;
    }

    await this.db.transaction(async (tx) => {
      await tx
        .update(schema.actions)
        .set({
          proofState: "user_confirmed_external_submission",
          status: "succeeded",
          updatedAt: new Date(),
        })
        .where(eq(schema.actions.id, actionId));

      await tx.insert(schema.submissions).values({
        missionId: actionRow.missionId,
        actionId,
        adapterName: isSocialPost ? "social_publisher" : "web",
        status: "sent",
        proofState: "user_confirmed_external_submission",
        externalReference: externalUrl ?? null,
        payloadHash: actionRow.canonicalPayloadHash,
        sentAt: new Date(),
      });

      await tx.insert(schema.missionEvents).values({
        missionId: actionRow.missionId,
        eventType: "action_executed",
        actorType: "user",
        payload: {
          actionId,
          proofState: "user_confirmed_external_submission",
          platform,
          externalUrl,
          message: `User confirmed external submission on ${platform}`,
        },
      });

      const [latestSnapshot] = await tx
        .select({ state: schema.missionStatusSnapshots.state })
        .from(schema.missionStatusSnapshots)
        .where(eq(schema.missionStatusSnapshots.missionId, actionRow.missionId))
        .orderBy(desc(schema.missionStatusSnapshots.createdAt))
        .limit(1);

      const newState = "waiting_for_response";
      const newRank = STATE_RANK[newState] ?? 0;
      const currentRank = STATE_RANK[latestSnapshot?.state ?? ""] ?? -1;

      if (newRank >= currentRank) {
        await tx.insert(schema.missionStatusSnapshots).values({
          missionId: actionRow.missionId,
          state: newState,
          headline,
          nextUserAction,
          nextSystemAction: "Follow up if no response within 7 days.",
          primaryButton,
        });
      }
    });

    return {
      actionId,
      proofState: "user_confirmed_external_submission" as const,
      platform,
      externalUrl: externalUrl ?? null,
    };
  }
}