import type {
  CommitMessageAiSettings,
  CommitMessageAiModelCapability
} from './commit-message-ai-types'
import { LOCAL_COMMIT_MESSAGE_HOST_KEY } from './commit-message-host-key'
import type { TuiAgent } from './tui-agent'
import type {
  RepoSourceControlAiOverrides,
  SourceControlAiModelChoice,
  SourceControlAiOperation,
  SourceControlAiSettings
} from './source-control-ai-types'

export function readSourceControlAiModelChoiceForHost(
  choice: SourceControlAiModelChoice | null | undefined,
  hostKey: string,
  agentId: TuiAgent
): string | undefined {
  return (
    choice?.selectedModelByAgentByHost?.[hostKey]?.[agentId] ??
    (hostKey === LOCAL_COMMIT_MESSAGE_HOST_KEY
      ? choice?.selectedModelByAgent?.[agentId]
      : undefined)
  )
}

export function selectSourceControlAiModelChoiceForHost(
  choice: SourceControlAiModelChoice | undefined,
  hostKey: string,
  agentId: TuiAgent,
  modelId: string
): SourceControlAiModelChoice {
  return {
    ...choice,
    selectedModelByAgent:
      hostKey === LOCAL_COMMIT_MESSAGE_HOST_KEY
        ? { ...choice?.selectedModelByAgent, [agentId]: modelId }
        : choice?.selectedModelByAgent,
    selectedModelByAgentByHost: {
      ...choice?.selectedModelByAgentByHost,
      [hostKey]: {
        ...choice?.selectedModelByAgentByHost?.[hostKey],
        [agentId]: modelId
      }
    }
  }
}

export function clearSourceControlAiModelChoiceForHost(
  choice: SourceControlAiModelChoice | undefined,
  hostKey: string,
  agentId: TuiAgent
): SourceControlAiModelChoice | undefined {
  if (!choice) {
    return undefined
  }
  const selectedModelByAgent = { ...choice.selectedModelByAgent }
  if (hostKey === LOCAL_COMMIT_MESSAGE_HOST_KEY) {
    delete selectedModelByAgent[agentId]
  }
  const selectedModelByAgentByHost = { ...choice.selectedModelByAgentByHost }
  const hostModels = { ...selectedModelByAgentByHost[hostKey] }
  delete hostModels[agentId]
  if (Object.keys(hostModels).length > 0) {
    selectedModelByAgentByHost[hostKey] = hostModels
  } else {
    delete selectedModelByAgentByHost[hostKey]
  }
  const nextChoice: SourceControlAiModelChoice = {}
  if (Object.keys(selectedModelByAgent).length > 0) {
    nextChoice.selectedModelByAgent = selectedModelByAgent
  }
  if (Object.keys(selectedModelByAgentByHost).length > 0) {
    nextChoice.selectedModelByAgentByHost = selectedModelByAgentByHost
  }
  const hasModelSelection =
    nextChoice.selectedModelByAgent !== undefined ||
    nextChoice.selectedModelByAgentByHost !== undefined
  if (hasModelSelection && Object.keys(choice.selectedThinkingByModel ?? {}).length > 0) {
    nextChoice.selectedThinkingByModel = choice.selectedThinkingByModel
  }
  return hasModelSelection ? nextChoice : undefined
}

export function mergeSelectedModelByAgentByHost(
  base: Partial<Record<string, Partial<Record<TuiAgent, string>>>> | undefined,
  override: Partial<Record<string, Partial<Record<TuiAgent, string>>>> | undefined
): Partial<Record<string, Partial<Record<TuiAgent, string>>>> {
  const merged = base === undefined ? {} : structuredClone(base)
  for (const [hostKey, hostModels] of Object.entries(override ?? {})) {
    merged[hostKey] = { ...merged[hostKey], ...hostModels }
  }
  return merged
}

export function getDiscoveredModels(
  source: SourceControlAiSettings,
  legacy: CommitMessageAiSettings | null | undefined,
  hostKey: string,
  agentId: TuiAgent
): CommitMessageAiModelCapability[] {
  return (
    source.discoveredModelsByAgentByHost?.[hostKey]?.[agentId] ??
    (hostKey === LOCAL_COMMIT_MESSAGE_HOST_KEY
      ? (source.discoveredModelsByAgent?.[agentId] ??
        legacy?.discoveredModelsByAgentByHost?.[hostKey]?.[agentId] ??
        legacy?.discoveredModelsByAgent?.[agentId] ??
        [])
      : (legacy?.discoveredModelsByAgentByHost?.[hostKey]?.[agentId] ?? []))
  )
}

export function selectPersistedModelId(args: {
  source: SourceControlAiSettings
  legacy: CommitMessageAiSettings | null | undefined
  repoOverrides: RepoSourceControlAiOverrides | null | undefined
  operation: SourceControlAiOperation
  hostKey: string
  agentId: TuiAgent
  defaultModelId: string
}): string {
  const { source, legacy, repoOverrides, operation, hostKey, agentId, defaultModelId } = args
  return (
    readSourceControlAiModelChoiceForHost(
      repoOverrides?.modelOverridesByOperation?.[operation],
      hostKey,
      agentId
    ) ??
    readSourceControlAiModelChoiceForHost(
      source.modelOverridesByOperation?.[operation],
      hostKey,
      agentId
    ) ??
    readSourceControlAiModelChoiceForHost(
      {
        selectedModelByAgent: source.selectedModelByAgent,
        selectedModelByAgentByHost: source.selectedModelByAgentByHost
      },
      hostKey,
      agentId
    ) ??
    legacy?.selectedModelByAgentByHost?.[hostKey]?.[agentId] ??
    (hostKey === LOCAL_COMMIT_MESSAGE_HOST_KEY
      ? legacy?.selectedModelByAgent?.[agentId]
      : undefined) ??
    defaultModelId
  )
}

export function resolveThinkingLevel(args: {
  model: CommitMessageAiModelCapability
  source: SourceControlAiSettings
  legacy: CommitMessageAiSettings | null | undefined
  repoOverrides: RepoSourceControlAiOverrides | null | undefined
  operation: SourceControlAiOperation
}): string | undefined {
  if (!args.model.thinkingLevels?.length) {
    return undefined
  }
  const persisted =
    args.repoOverrides?.modelOverridesByOperation?.[args.operation]?.selectedThinkingByModel?.[
      args.model.id
    ] ??
    args.source.modelOverridesByOperation?.[args.operation]?.selectedThinkingByModel?.[
      args.model.id
    ] ??
    args.source.selectedThinkingByModel[args.model.id] ??
    args.legacy?.selectedThinkingByModel?.[args.model.id]
  return args.model.thinkingLevels.some((level) => level.id === persisted)
    ? persisted
    : args.model.defaultThinkingLevel
}