/**
 * Project Hierarchy Utilities
 * 
 * Functions for extracting language from ATLAS-ID, detecting content category,
 * calculating hierarchy depth, and generating job IDs.
 */

import type { Project, ContentCategory, HierarchyNode, Episode } from "../types/project";

/**
 * Extracts target language code from ATLAS-ID
 * Format: "1234567-DE" → "DE"
 */
export function extractLanguageFromAtlasId(atlasId: string | undefined): string | null {
  if (!atlasId) return null;
  
  const match = atlasId.match(/-([A-Z]{2})$/i);
  return match ? match[1].toUpperCase() : null;
}

/**
 * Extracts the base ID from ATLAS-ID (without language suffix)
 * Format: "1234567-DE" → "1234567"
 */
export function extractBaseAtlasId(atlasId: string | undefined): string | null {
  if (!atlasId) return null;
  
  const match = atlasId.match(/^(\d+)/);
  return match ? match[1] : null;
}

/**
 * Generates episode job ID from project ATLAS-ID and episode sequence
 * Format: "1234567-DE" + episode 1 → "1234567_1"
 */
export function generateEpisodeJobId(atlasId: string | undefined, episodeNumber: number): string | null {
  const baseId = extractBaseAtlasId(atlasId);
  if (!baseId) return null;
  
  return `${baseId}_${episodeNumber}`;
}

/**
 * Parses episode job ID to extract base ID and sequence number
 * Format: "1234567_1" → { baseId: "1234567", sequence: 1 }
 */
export function parseEpisodeJobId(jobId: string | undefined): { baseId: string; sequence: number } | null {
  if (!jobId) return null;
  
  const match = jobId.match(/^(\d+)_(\d+)$/);
  if (!match) return null;
  
  return {
    baseId: match[1],
    sequence: parseInt(match[2], 10)
  };
}

/**
 * A flexible project type that accepts both the strict Project type
 * and the inferred type from mockProjects
 */
type ProjectLike = {
  content?: string;
  type?: string;
  season?: string | null;
  batch?: string | null;
  episodesList?: unknown[];
  parentGroupId?: string | null;
  projectGroupTitle?: string | null;
  atlasId?: string;
  bcId?: string;
  language?: string;
};

/**
 * Determines content category from project fields
 * Uses 'content' field primarily (Feature, Episode, Trailer, Promo, etc.)
 */
export function getContentCategory(project: ProjectLike): ContentCategory {
  const content = project.content?.toLowerCase() || "";
  const type = project.type?.toLowerCase() || "";
  
  if (content === "feature" || type.includes("film") || type.includes("movie")) {
    return "movie";
  }
  
  if (content === "episode" || type.includes("series")) {
    return "series";
  }
  
  if (content === "trailer") {
    return "trailer";
  }
  
  if (content === "promo" || content === "advertisement") {
    return "promo";
  }
  
  return "other";
}

/**
 * Returns display icon identifier for content category
 */
export function getContentCategoryIcon(category: ContentCategory): string {
  switch (category) {
    case "series": return "tv";
    case "movie": return "film";
    case "trailer": return "clapperboard";
    case "promo": return "megaphone";
    default: return "file";
  }
}

/**
 * Returns human-readable label for content category
 */
export function getContentCategoryLabel(category: ContentCategory): string {
  switch (category) {
    case "series": return "Series";
    case "movie": return "Movie";
    case "trailer": return "Trailer";
    case "promo": return "Promo";
    default: return "Other";
  }
}

/**
 * Calculates hierarchy depth for a project (levels below title)
 * Returns number of levels below title: Season(0-1) + Batch(0-1) + Episodes(0-1)
 * 
 * Note: This counts levels in the PROJECT's internal hierarchy, not including
 * external grouping. Group level is handled separately at the ProjectGroup level.
 * 
 * Examples:
 * - Movie (flat): depth = 0 (no seasons, batches, or episodes list)
 * - Series S01: depth = 1 (season only)
 * - Series S01/B01: depth = 2 (season + batch)
 * - Series S01/B01/EP1-10: depth = 3 (season + batch + episodes)
 */
export function getHierarchyDepth(project: Project): number {
  let depth = 0;
  
  if (project.season) {
    depth += 1;
  }
  
  if (project.batch) {
    depth += 1;
  }
  
  if (project.episodesList && project.episodesList.length > 0) {
    depth += 1;
  }
  
  return depth;
}

/**
 * Determines which hierarchy levels are present for a project
 * 
 * Note: `belongsToGroup` indicates whether this project is part of a ProjectGroup,
 * not a structural hierarchy level within the project itself.
 */
export function getHierarchyLevels(project: ProjectLike): {
  belongsToGroup: boolean;
  hasSeason: boolean;
  hasBatch: boolean;
  hasEpisodes: boolean;
} {
  return {
    belongsToGroup: !!(project.parentGroupId || project.projectGroupTitle),
    hasSeason: !!project.season,
    hasBatch: !!project.batch,
    hasEpisodes: !!(project.episodesList && project.episodesList.length > 0)
  };
}

/**
 * Converts a flat project to a hierarchy tree node with children
 */
export function projectToHierarchyNode(project: Project, parentId?: string): HierarchyNode {
  const atlasId = project.atlasId || project.bcId;
  const language = project.language || extractLanguageFromAtlasId(atlasId) || undefined;
  const contentCategory = getContentCategory(project);
  
  const children: HierarchyNode[] = [];
  let currentDepth = 1;
  
  // Add season level if present
  if (project.season) {
    const seasonNode: HierarchyNode = {
      id: `${project.id}-season-${project.season}`,
      type: "season",
      label: project.season,
      language,
      depth: currentDepth + 1,
      parentId: project.id,
      projectId: project.id,
      children: []
    };
    
    // Add batch level if present
    if (project.batch) {
      const batchNode: HierarchyNode = {
        id: `${project.id}-batch-${project.batch}`,
        type: "batch",
        label: project.batch,
        language,
        depth: currentDepth + 2,
        parentId: seasonNode.id,
        projectId: project.id,
        children: []
      };
      
      // Add episodes under batch
      if (project.episodesList && project.episodesList.length > 0) {
        batchNode.children = project.episodesList.map((ep, idx) => 
          episodeToHierarchyNode(ep, project, batchNode.id, currentDepth + 3)
        );
      }
      
      seasonNode.children = [batchNode];
    } else if (project.episodesList && project.episodesList.length > 0) {
      // Episodes directly under season (no batch)
      seasonNode.children = project.episodesList.map((ep, idx) => 
        episodeToHierarchyNode(ep, project, seasonNode.id, currentDepth + 2)
      );
    }
    
    children.push(seasonNode);
  } else if (project.batch) {
    // Batch without season
    const batchNode: HierarchyNode = {
      id: `${project.id}-batch-${project.batch}`,
      type: "batch",
      label: project.batch,
      language,
      depth: currentDepth + 1,
      parentId: project.id,
      projectId: project.id,
      children: []
    };
    
    if (project.episodesList && project.episodesList.length > 0) {
      batchNode.children = project.episodesList.map((ep, idx) => 
        episodeToHierarchyNode(ep, project, batchNode.id, currentDepth + 2)
      );
    }
    
    children.push(batchNode);
  } else if (project.episodesList && project.episodesList.length > 0) {
    // Episodes directly under title (flat structure)
    children.push(...project.episodesList.map((ep, idx) => 
      episodeToHierarchyNode(ep, project, project.id, currentDepth + 1)
    ));
  }
  
  return {
    id: project.id,
    type: "title",
    label: project.title,
    atlasId,
    language,
    contentCategory,
    status: project.status,
    depth: currentDepth,
    parentId,
    projectId: project.id,
    children: children.length > 0 ? children : undefined
  };
}

/**
 * Converts an episode to a hierarchy node
 */
function episodeToHierarchyNode(
  episode: Episode, 
  project: Project, 
  parentId: string, 
  depth: number
): HierarchyNode {
  const atlasId = project.atlasId || project.bcId;
  const jobId = episode.jobId || generateEpisodeJobId(atlasId, episode.number) || undefined;
  const language = project.language || extractLanguageFromAtlasId(atlasId) || undefined;
  
  return {
    id: `${project.id}-ep-${episode.number}`,
    type: "episode",
    label: `${episode.prefix || "EP"}${episode.number} - ${episode.title}`,
    jobId,
    language,
    status: episode.milestones?.delivery?.status,
    depth,
    parentId,
    projectId: project.id,
    episodeNumber: episode.number
  };
}

/**
 * Groups projects by their ATLAS-ID to identify shared orders
 */
export function groupProjectsByAtlasId(projects: Project[]): Map<string, Project[]> {
  const groups = new Map<string, Project[]>();
  
  for (const project of projects) {
    const baseId = extractBaseAtlasId(project.atlasId || project.bcId);
    if (!baseId) continue;
    
    const existing = groups.get(baseId) || [];
    existing.push(project);
    groups.set(baseId, existing);
  }
  
  return groups;
}

/**
 * Groups projects by their target language
 */
export function groupProjectsByLanguage(projects: Project[]): Map<string, Project[]> {
  const groups = new Map<string, Project[]>();
  
  for (const project of projects) {
    const atlasId = project.atlasId || project.bcId;
    const language = project.language || extractLanguageFromAtlasId(atlasId) || "Unknown";
    
    const existing = groups.get(language) || [];
    existing.push(project);
    groups.set(language, existing);
  }
  
  return groups;
}

/**
 * Gets unique languages from a list of projects
 */
export function getUniqueLanguages(projects: Project[]): string[] {
  const languages = new Set<string>();
  
  for (const project of projects) {
    const atlasId = project.atlasId || project.bcId;
    const language = project.language || extractLanguageFromAtlasId(atlasId);
    if (language) {
      languages.add(language);
    }
  }
  
  return Array.from(languages).sort();
}

/**
 * Filters projects by content category
 * Uses generics to preserve the input array type
 */
export function filterByContentCategory<T extends ProjectLike>(projects: T[], categories: ContentCategory | ContentCategory[]): T[] {
  const categoryArray = Array.isArray(categories) ? categories : [categories];
  if (categoryArray.length === 0) return projects;
  
  return projects.filter(project => {
    const category = getContentCategory(project);
    return categoryArray.includes(category);
  });
}

/**
 * Filters projects by language
 * Uses generics to preserve the input array type
 */
export function filterByLanguage<T extends ProjectLike>(
  projects: T[], 
  languages: string | string[]
): T[] {
  const langArray = Array.isArray(languages) ? languages : [languages];
  if (langArray.length === 0) return projects;
  
  return projects.filter(project => {
    const atlasId = project.atlasId || project.bcId || "";
    const projectLanguage = project.language || extractLanguageFromAtlasId(atlasId);
    return projectLanguage && langArray.includes(projectLanguage);
  });
}

/**
 * Filters projects by hierarchy depth (number of levels: 0-3)
 * Uses generics to preserve the input array type
 */
export function filterByHierarchyDepth<T extends ProjectLike>(
  projects: T[], 
  depth: number | {
    hasSeasons?: boolean;
    hasBatches?: boolean;
    hasEpisodes?: boolean;
    isFlat?: boolean;
    belongsToGroup?: boolean;
  }
): T[] {
  // Simple depth filter
  if (typeof depth === "number") {
    return projects.filter(project => {
      let projectDepth = 0;
      if (project.season) projectDepth += 1;
      if (project.batch) projectDepth += 1;
      if (project.episodesList && project.episodesList.length > 0) projectDepth += 1;
      return projectDepth === depth;
    });
  }
  
  // Options-based filter
  const options = depth;
  return projects.filter(project => {
    const levels = getHierarchyLevels(project);
    
    if (options.hasSeasons !== undefined && levels.hasSeason !== options.hasSeasons) {
      return false;
    }
    
    if (options.hasBatches !== undefined && levels.hasBatch !== options.hasBatches) {
      return false;
    }
    
    if (options.hasEpisodes !== undefined && levels.hasEpisodes !== options.hasEpisodes) {
      return false;
    }
    
    if (options.belongsToGroup !== undefined && levels.belongsToGroup !== options.belongsToGroup) {
      return false;
    }
    
    if (options.isFlat !== undefined) {
      const isFlat = !levels.hasSeason && !levels.hasBatch && !levels.hasEpisodes;
      if (isFlat !== options.isFlat) {
        return false;
      }
    }
    
    return true;
  });
}