import { getCurrentUser } from "@/lib/auth";
import { prisma } from "@/lib/prisma";
import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";

/**
 * GET /api/exercises/[id]
 * Get exercise with history
 */
export async function GET(
  _request: NextRequest,
  { params }: { params: { id: string } }
) {
  try {
    const user = await getCurrentUser();
    if (!user) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const exercise = await prisma.exercise.findFirst({
      where: {
        id: params.id,
        userId: user.id,
      },
    });

    if (!exercise) {
      return NextResponse.json({ error: "Exercise not found" }, { status: 404 });
    }

    // Get exercise history grouped by workout
    const setLogs = await prisma.setLog.findMany({
      where: {
        exerciseId: params.id,
        workout: {
          userId: user.id,
        },
      },
      include: {
        workout: {
          select: {
            id: true,
            date: true,
            name: true,
          },
        },
      },
      orderBy: [
        { workout: { date: "desc" } },
        { setNumber: "asc" },
      ],
      take: 100,
    });

    // Group by workout
    const workoutMap = new Map<string, { workout: any; sets: any[] }>();
    for (const log of setLogs) {
      const key = log.workoutId;
      if (!workoutMap.has(key)) {
        workoutMap.set(key, { workout: log.workout, sets: [] });
      }
      workoutMap.get(key)!.sets.push(log);
    }

    const history = Array.from(workoutMap.values()).slice(0, 20);

    return NextResponse.json({
      exercise,
      history,
    });
  } catch (error) {
    console.error("GET /api/exercises/[id] error:", error);
    return NextResponse.json(
      { error: "Internal server error" },
      { status: 500 }
    );
  }
}

/**
 * PATCH /api/exercises/[id]
 * Edit exercise details
 */
const updateExerciseSchema = z.object({
  name: z.string().min(1).optional(),
  type: z.string().min(1).optional(),
  muscleGroups: z.array(z.string()).optional(),
  description: z.string().optional(),
  inputFields: z.array(z.string().min(1)).optional(),
  defaultWeightUnit: z.string().nullable().optional(),
});

export async function PATCH(
  request: NextRequest,
  { params }: { params: { id: string } }
) {
  try {
    const user = await getCurrentUser();
    if (!user) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const exercise = await prisma.exercise.findFirst({
      where: {
        id: params.id,
        userId: user.id,
      },
    });

    if (!exercise) {
      return NextResponse.json({ error: "Exercise not found" }, { status: 404 });
    }

    const body = await request.json();
    const validated = updateExerciseSchema.parse(body);

    const data: any = {};
    if (validated.name !== undefined) data.name = validated.name;
    if (validated.type !== undefined) data.type = validated.type;
    if (validated.description !== undefined) data.description = validated.description;
    if (validated.muscleGroups !== undefined)
      data.muscleGroups = JSON.stringify(validated.muscleGroups);
    if (validated.inputFields !== undefined)
      data.inputFields = JSON.stringify(validated.inputFields);
    if (validated.defaultWeightUnit !== undefined)
      data.defaultWeightUnit = validated.defaultWeightUnit;

    const updated = await prisma.exercise.update({
      where: { id: params.id },
      data,
    });

    return NextResponse.json(updated);
  } catch (error) {
    if (error instanceof z.ZodError) {
      return NextResponse.json(
        { error: "Invalid data", details: error.errors },
        { status: 400 }
      );
    }
    console.error("PATCH /api/exercises/[id] error:", error);
    return NextResponse.json(
      { error: "Internal server error" },
      { status: 500 }
    );
  }
}

/**
 * DELETE /api/exercises/[id]
 */
export async function DELETE(
  _request: NextRequest,
  { params }: { params: { id: string } }
) {
  try {
    const user = await getCurrentUser();
    if (!user) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const exercise = await prisma.exercise.findFirst({
      where: {
        id: params.id,
        userId: user.id,
      },
    });

    if (!exercise) {
      return NextResponse.json({ error: "Exercise not found" }, { status: 404 });
    }

    await prisma.setLog.deleteMany({
      where: { exerciseId: params.id },
    });

    await prisma.exercise.delete({
      where: { id: params.id },
    });

    return NextResponse.json({ message: "Exercise deleted successfully" });
  } catch (error) {
    console.error("DELETE /api/exercises/[id] error:", error);
    return NextResponse.json(
      { error: "Internal server error" },
      { status: 500 }
    );
  }
}