"use client"

import { useState } from "react"
import { useRouter } from "next/navigation"

interface Player {
  id: number
  name: string
  currentElo: number
}

interface Team {
  id: number
  teamName: string | null
  player1: Player
  player2: Player
}

interface TeamsSectionProps {
  tournamentId: number
  participants: Player[]
  teamDurability: string
  partnerRotation: string
  allowByes: boolean
}

type TeamDurabilityOption = 'permanent' | 'variable' | 'per_round'
type PartnerRotationOption = 'none' | 'minimize_repeat' | 'maximize_even' | 'elo_based'

export default function TeamsSection({
  tournamentId,
  participants,
  teamDurability: initialTeamDurability,
  partnerRotation: initialPartnerRotation,
  allowByes: initialAllowByes,
}: TeamsSectionProps) {
  const router = useRouter()
  const [teams, setTeams] = useState<Team[]>([])
  const [teamDurability, setTeamDurability] = useState<TeamDurabilityOption>(initialTeamDurability as TeamDurabilityOption)
  const [partnerRotation, setPartnerRotation] = useState<PartnerRotationOption>(initialPartnerRotation as PartnerRotationOption)
  const [allowByes, setAllowByes] = useState(initialAllowByes)
  const [isGenerating, setIsGenerating] = useState(false)
  const [error, setError] = useState("")
  const [success, setSuccess] = useState("")
  
  // Manual team entry state
  const [manualTeamMode, setManualTeamMode] = useState(false)
  const [selectedPlayer1, setSelectedPlayer1] = useState<number | null>(null)
  const [selectedPlayer2, setSelectedPlayer2] = useState<number | null>(null)
  const [newTeamName, setNewTeamName] = useState("")

  const handleSaveConfig = async () => {
    setError("")
    setSuccess("")
    setIsGenerating(true)

    try {
      const response = await fetch(`/api/tournaments/${tournamentId}`, {
        method: "PUT",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          teamDurability,
          partnerRotation,
          allowByes,
        }),
      })

      if (!response.ok) {
        try {
          const errorData = await response.json()
          setError(errorData.error || "Failed to save configuration")
        } catch {
          setError(`Failed to save configuration: ${response.status} ${response.statusText}`)
        }
        return
      }

      setSuccess("Configuration saved successfully!")
      router.refresh()
    } catch (err) {
      if (err instanceof Error) {
        setError(err.message)
      } else {
        setError("An unknown error occurred")
      }
    } finally {
      setIsGenerating(false)
    }
  }

  const handleGenerateSchedule = async () => {
    if (participants.length < 2) {
      setError("At least 2 participants are required to generate a schedule")
      return
    }

    if (participants.length % 2 !== 0 && !allowByes) {
      setError("Odd number of participants. Enable 'Allow Byes' to proceed.")
      return
    }

    setError("")
    setSuccess("")
    setIsGenerating(true)

    try {
      const response = await fetch(`/api/tournaments/${tournamentId}/schedule`, {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
      })

      if (!response.ok) {
        try {
          const errorData = await response.json()
          setError(errorData.error || "Failed to generate schedule")
        } catch {
          setError(`Failed to generate schedule: ${response.status} ${response.statusText}`)
        }
        setIsGenerating(false)
        return
      }

      const data = await response.json()
      // Update teams from the generated schedule
      // Extract teams from round matchups
      const generatedTeams: Team[] = []
      for (const round of data.rounds) {
        for (const matchup of round.bracketMatchups) {
          // Create unique keys based on player IDs
          const team1Key = `${matchup.player1P1.id}-${matchup.player1P2.id}`
          const team2Key = `${matchup.player2P1.id}-${matchup.player2P2.id}`
          
          // Add unique teams
          const team1 = {
            id: matchup.player1P1.id * 10000 + matchup.player1P2.id,
            teamName: `${matchup.player1P1.name} & ${matchup.player1P2.name}`,
            player1: matchup.player1P1,
            player2: matchup.player1P2,
          }
          const team2 = {
            id: matchup.player2P1.id * 10000 + matchup.player2P2.id,
            teamName: `${matchup.player2P1.name} & ${matchup.player2P2.name}`,
            player1: matchup.player2P1,
            player2: matchup.player2P2,
          }
          
          // Check if team already exists
          const existingTeam1 = generatedTeams.find(
            t => t.player1.id === team1.player1.id && t.player2.id === team1.player2.id
          )
          if (!existingTeam1) generatedTeams.push(team1)
          
          const existingTeam2 = generatedTeams.find(
            t => t.player1.id === team2.player1.id && t.player2.id === team2.player2.id
          )
          if (!existingTeam2) generatedTeams.push(team2)
        }
      }
      setTeams(generatedTeams)
      setSuccess(`Successfully generated ${data.roundsCreated} rounds with ${data.matchupsCreated} matchups!`)
      router.refresh()
    } catch (err) {
      if (err instanceof Error) {
        setError(err.message)
      } else {
        setError("An unknown error occurred")
      }
    } finally {
      setIsGenerating(false)
    }
  }

  const handleDeleteTeams = async () => {
    if (!confirm("Are you sure you want to delete the schedule? This will remove all rounds and matchups.")) {
      return
    }

    setError("")
    setSuccess("")
    setIsGenerating(true)

    try {
      // Delete schedule (which includes matchups/rounds)
      const response = await fetch(`/api/tournaments/${tournamentId}/schedule`, {
        method: "DELETE",
      })

      if (!response.ok) {
        try {
          const errorData = await response.json()
          setError(errorData.error || "Failed to delete schedule")
        } catch {
          setError(`Failed to delete schedule: ${response.status} ${response.statusText}`)
        }
        return
      }

      setTeams([])
      setSuccess("Schedule deleted successfully!")
      router.refresh()
    } catch (err) {
      if (err instanceof Error) {
        setError(err.message)
      } else {
        setError("An unknown error occurred")
      }
    } finally {
      setIsGenerating(false)
    }
  }

  // Handle adding a manual team
  const handleAddManualTeam = () => {
    if (!selectedPlayer1 || !selectedPlayer2) {
      setError("Please select two players for the team")
      return
    }
    
    if (selectedPlayer1 === selectedPlayer2) {
      setError("A player cannot be on a team with themselves")
      return
    }
    
    // Check if player is already in a team
    const player1InTeam = teams.some(t => t.player1.id === selectedPlayer1 || t.player2.id === selectedPlayer1)
    const player2InTeam = teams.some(t => t.player1.id === selectedPlayer2 || t.player2.id === selectedPlayer2)
    
    if (player1InTeam || player2InTeam) {
      setError("One or both players are already on a team")
      return
    }
    
    const player1 = participants.find(p => p.id === selectedPlayer1)
    const player2 = participants.find(p => p.id === selectedPlayer2)
    
    if (!player1 || !player2) {
      setError("Invalid player selection")
      return
    }
    
    const newTeam: Team = {
      id: player1.id * 10000 + player2.id,
      teamName: newTeamName || `${player1.name} & ${player2.name}`,
      player1,
      player2,
    }
    
    setTeams([...teams, newTeam])
    setSelectedPlayer1(null)
    setSelectedPlayer2(null)
    setNewTeamName("")
    setError("")
    setSuccess("Team added!")
    
    // Clear success message after 2 seconds
    setTimeout(() => setSuccess(""), 2000)
  }

  // Handle removing a manual team
  const handleRemoveTeam = (teamId: number) => {
    setTeams(teams.filter(t => t.id !== teamId))
    setSuccess("Team removed!")
    setTimeout(() => setSuccess(""), 2000)
  }

  // Handle saving manual teams
  const handleSaveManualTeams = async () => {
    if (teams.length === 0) {
      setError("Please add at least one team")
      return
    }
    
    setError("")
    setSuccess("")
    setIsGenerating(true)
    
    try {
      // For permanent teams with manual entry, we need to save the team list
      // This would require a new API endpoint or extending the tournament update
      const response = await fetch(`/api/tournaments/${tournamentId}`, {
        method: "PUT",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          teamDurability: "permanent",
          manualTeams: teams.map(t => ({
            player1Id: t.player1.id,
            player2Id: t.player2.id,
            teamName: t.teamName,
          })),
        }),
      })
      
      if (!response.ok) {
        const errorData = await response.json()
        throw new Error(errorData.error || "Failed to save teams")
      }
      
      setSuccess("Teams saved successfully!")
      router.refresh()
    } catch (err) {
      if (err instanceof Error) {
        setError(err.message)
      } else {
        setError("An unknown error occurred")
      }
    } finally {
      setIsGenerating(false)
    }
  }

  return (
    <div className="bg-white shadow rounded-lg p-6 mb-6">
      <h2 className="text-lg font-medium text-gray-900 mb-4">
        Matchups {teams.length > 0 && `(${teams.length})`}
      </h2>

      {/* Configuration Panel */}
      <div className="bg-gray-50 rounded-lg p-4 mb-6">
        <h3 className="text-sm font-medium text-gray-700 mb-3">Team Configuration</h3>

        {/* Team Durability */}
        <div className="mb-4">
          <label className="block text-sm font-medium text-gray-600 mb-2">
            Team Durability
          </label>
          <div className="flex gap-4">
            <label className="flex items-center">
              <input
                type="radio"
                name="teamDurability"
                value="permanent"
                checked={teamDurability === 'permanent'}
                onChange={(e) => setTeamDurability(e.target.value as TeamDurabilityOption)}
                className="mr-2"
              />
              <span className="text-sm">Permanent Teams</span>
            </label>
            <label className="flex items-center">
              <input
                type="radio"
                name="teamDurability"
                value="variable"
                checked={teamDurability === 'variable'}
                onChange={(e) => setTeamDurability(e.target.value as TeamDurabilityOption)}
                className="mr-2"
              />
              <span className="text-sm">Pre-Planned Variable</span>
            </label>
            <label className="flex items-center">
              <input
                type="radio"
                name="teamDurability"
                value="per_round"
                checked={teamDurability === 'per_round'}
                onChange={(e) => setTeamDurability(e.target.value as TeamDurabilityOption)}
                className="mr-2"
              />
              <span className="text-sm">Dynamic/Progressive</span>
            </label>
          </div>
          <p className="text-xs text-gray-500 mt-1">
            {teamDurability === 'permanent' 
              ? 'Teams formed once and stay fixed throughout the tournament.'
              : teamDurability === 'variable'
              ? 'Fresh teams each round with partner rotation. Schedule is pre-planned.'
              : 'Teams formed based on results. Schedule progresses as rounds complete.'}
          </p>
        </div>

          {/* Partner Rotation (for variable/per_round teams) */}
          {(teamDurability === 'variable' || teamDurability === 'per_round') && (
            <div className="mb-4">
              <label className="block text-sm font-medium text-gray-600 mb-2">
                Partner Rotation Strategy
              </label>
              <div className="flex gap-4 flex-wrap">
                <label className="flex items-center">
                  <input
                    type="radio"
                    name="partnerRotation"
                    value="none"
                    checked={partnerRotation === 'none'}
                    onChange={(e) => setPartnerRotation(e.target.value as PartnerRotationOption)}
                    className="mr-2"
                  />
                  <span className="text-sm">None (Random)</span>
                </label>
                <label className="flex items-center">
                  <input
                    type="radio"
                    name="partnerRotation"
                    value="minimize_repeat"
                    checked={partnerRotation === 'minimize_repeat'}
                    onChange={(e) => setPartnerRotation(e.target.value as PartnerRotationOption)}
                    className="mr-2"
                  />
                  <span className="text-sm">Minimize Repeat</span>
                </label>
                <label className="flex items-center">
                  <input
                    type="radio"
                    name="partnerRotation"
                    value="maximize_even"
                    checked={partnerRotation === 'maximize_even'}
                    onChange={(e) => setPartnerRotation(e.target.value as PartnerRotationOption)}
                    className="mr-2"
                  />
                  <span className="text-sm">Maximize Even</span>
                </label>
                <label className="flex items-center">
                  <input
                    type="radio"
                    name="partnerRotation"
                    value="elo_based"
                    checked={partnerRotation === 'elo_based'}
                    onChange={(e) => setPartnerRotation(e.target.value as PartnerRotationOption)}
                    className="mr-2"
                  />
                  <span className="text-sm">ELO-Based</span>
                </label>
              </div>
            </div>
          )}

          {/* Manual Team Entry Toggle (for permanent teams) */}
          {teamDurability === 'permanent' && (
            <div className="mb-4">
              <label className="flex items-center">
                <input
                  type="checkbox"
                  checked={manualTeamMode}
                  onChange={(e) => setManualTeamMode(e.target.checked)}
                  className="mr-2"
                />
                <span className="text-sm font-medium text-gray-600">Enter teams manually</span>
              </label>
              <p className="text-xs text-gray-500 mt-1 ml-6">
                Check this to manually create teams instead of auto-generating them.
              </p>
            </div>
          )}

        {/* Allow Byes (for odd participant counts) */}
        <div className="mb-4">
          <label className="flex items-center">
            <input
              type="checkbox"
              checked={allowByes}
              onChange={(e) => setAllowByes(e.target.checked)}
              className="mr-2"
            />
            <span className="text-sm font-medium text-gray-600">Allow Byes (for odd number of participants)</span>
          </label>
          <p className="text-xs text-gray-500 mt-1 ml-6">
            When enabled, one player will have a bye each round if there's an odd number of participants.
          </p>
        </div>

        {/* Action Buttons */}
        <div className="flex gap-3 mt-4">
          <button
            onClick={handleSaveConfig}
            disabled={isGenerating}
            className="px-4 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700 disabled:opacity-50 text-sm"
          >
            {isGenerating ? "Saving..." : "Save Configuration"}
          </button>
        </div>
      </div>

      {/* Error/Success Messages */}
      {error && (
        <div className="rounded-md bg-red-50 p-4 mb-4">
          <div className="text-sm text-red-700">{error}</div>
        </div>
      )}

      {success && (
        <div className="rounded-md bg-green-50 p-4 mb-4">
          <div className="text-sm text-green-700">{success}</div>
        </div>
      )}

      {/* Manual Team Entry Form */}
      {manualTeamMode && teamDurability === 'permanent' && (
        <div className="bg-gray-50 rounded-lg p-4 mb-6 border-2 border-dashed border-gray-300">
          <h3 className="text-sm font-medium text-gray-700 mb-3">Manual Team Entry</h3>
          
          <div className="grid grid-cols-2 gap-4 mb-4">
            <div>
              <label className="block text-sm font-medium text-gray-600 mb-2">
                Player 1
              </label>
              <select
                value={selectedPlayer1 || ""}
                onChange={(e) => setSelectedPlayer1(e.target.value ? parseInt(e.target.value) : null)}
                className="w-full px-3 py-2 border border-gray-300 rounded-md text-sm"
              >
                <option value="">Select player...</option>
                {participants
                  .filter(p => !teams.some(t => t.player1.id === p.id || t.player2.id === p.id))
                  .map(p => (
                    <option key={p.id} value={p.id}>{p.name} (Elo: {p.currentElo})</option>
                  ))}
              </select>
            </div>
            
            <div>
              <label className="block text-sm font-medium text-gray-600 mb-2">
                Player 2
              </label>
              <select
                value={selectedPlayer2 || ""}
                onChange={(e) => setSelectedPlayer2(e.target.value ? parseInt(e.target.value) : null)}
                className="w-full px-3 py-2 border border-gray-300 rounded-md text-sm"
              >
                <option value="">Select player...</option>
                {participants
                  .filter(p => p.id !== selectedPlayer1 && !teams.some(t => t.player1.id === p.id || t.player2.id === p.id))
                  .map(p => (
                    <option key={p.id} value={p.id}>{p.name} (Elo: {p.currentElo})</option>
                  ))}
              </select>
            </div>
          </div>
          
          <div className="mb-4">
            <label className="block text-sm font-medium text-gray-600 mb-2">
              Team Name (optional)
            </label>
            <input
              type="text"
              value={newTeamName}
              onChange={(e) => setNewTeamName(e.target.value)}
              placeholder="e.g., The Aces"
              className="w-full px-3 py-2 border border-gray-300 rounded-md text-sm"
            />
          </div>
          
          <div className="flex gap-3">
            <button
              onClick={handleAddManualTeam}
              disabled={!selectedPlayer1 || !selectedPlayer2}
              className="px-4 py-2 bg-green-600 text-white rounded-md hover:bg-green-700 disabled:opacity-50 text-sm"
            >
              Add Team
            </button>
            <button
              onClick={() => {
                setSelectedPlayer1(null)
                setSelectedPlayer2(null)
                setNewTeamName("")
              }}
              className="px-4 py-2 bg-gray-300 text-gray-700 rounded-md hover:bg-gray-400 text-sm"
            >
              Clear
            </button>
          </div>
        </div>
      )}

      {/* Team Generation Controls */}
      <div className="flex gap-3 mb-4">
        {!manualTeamMode && (
          <>
            <button
              onClick={handleGenerateSchedule}
              disabled={isGenerating || participants.length < 2}
              className="px-4 py-2 bg-green-600 text-white rounded-md hover:bg-green-700 disabled:opacity-50 text-sm"
            >
              {isGenerating ? "Generating..." : `Generate Schedule (${participants.length} participants)`}
            </button>

            {teams.length > 0 && (
              <button
                onClick={handleDeleteTeams}
                disabled={isGenerating}
                className="px-4 py-2 bg-red-600 text-white rounded-md hover:bg-red-700 disabled:opacity-50 text-sm"
              >
                Delete Schedule
              </button>
            )}
          </>
        )}
        
        {manualTeamMode && teams.length > 0 && (
          <button
            onClick={handleSaveManualTeams}
            disabled={isGenerating}
            className="px-4 py-2 bg-green-600 text-white rounded-md hover:bg-green-700 disabled:opacity-50 text-sm"
          >
            {isGenerating ? "Saving..." : `Save ${teams.length} Team(s)`}
          </button>
        )}
      </div>

      {/* Teams Display */}
      {teams.length > 0 ? (
        <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
          {teams.map((team) => (
            <div
              key={`${team.player1.id}-${team.player2.id}`}
              className="bg-gray-50 rounded p-3 flex justify-between items-center"
            >
              <div>
                <p className="font-medium text-gray-900">
                  {team.player1.name} + {team.player2.name}
                </p>
                <p className="text-sm text-gray-500">
                  {team.teamName || `Team ${team.id}`}
                </p>
              </div>
              <div className="flex items-center gap-3">
                <div className="text-right">
                  <p className="text-sm text-gray-500">
                    ELO: {team.player1.currentElo} + {team.player2.currentElo} = {team.player1.currentElo + team.player2.currentElo}
                  </p>
                </div>
                {manualTeamMode && (
                  <button
                    onClick={() => handleRemoveTeam(team.id)}
                    className="text-red-600 hover:text-red-800 text-sm"
                  >
                    Remove
                  </button>
                )}
              </div>
            </div>
          ))}
        </div>
      ) : (
        <p className="text-gray-500">
          {manualTeamMode 
            ? "No teams created yet. Use the form above to add teams manually."
            : "No teams created yet. Configure options above and click Generate Schedule."}
        </p>
      )}

      {/* Participants Summary */}
      <div className="mt-6 pt-4 border-t border-gray-200">
        <h3 className="text-sm font-medium text-gray-700 mb-2">
          Available Participants ({participants.length})
        </h3>
        <div className="grid grid-cols-2 md:grid-cols-4 gap-2">
          {participants.map((player) => (
            <div key={player.id} className="text-sm text-gray-600 bg-gray-100 rounded px-2 py-1">
              {player.name} ({player.currentElo})
            </div>
          ))}
        </div>
      </div>
    </div>
  )
}